More or less moose: how is the hunting value affected?

In Sweden, management of moose is important due to considerable values as well as costs associated with this game species. An overarching question is how much moose Sweden should have. This short communication is delimited to the question of what the hunting value of moose is and what the hunting value would be given alternative levels of moose population density and allowed harvest. It is based on data from a mail contingent valuation survey that involved randomly selected hunters from a national register. The results showed that moose was the economically most important game species in Swedish hunting. The results also suggested that the hunting value would increase, but at a decreasing rate, if the moose population density and allowed harvest were increased – and vice versa. The findings should be of considerable interest in the context of adaptive moose management.     

Enhanced turbulence and energy dissipation at ocean fronts

The ocean surface boundary layer mediates air-sea exchange. In the classical paradigm and in current climate models, its turbulence is driven by atmospheric forcing. Observations at a 1-kilometer-wide front within the Kuroshio Current indicate that the rate of energy dissipation within the boundary layer is enhanced by one to two orders of magnitude, suggesting that the front, rather than the atmospheric forcing, supplied the energy for the turbulence. The data quantitatively support the hypothesis that winds aligned with the frontal velocity catalyzed a release of energy from the front to the turbulence. The resulting boundary layer is stratified in contrast to the classically well-mixed layer. These effects will be strongest at the intense fronts found in the Kuroshio Current, the Gulf Stream, and the Antarctic Circumpolar Current, all of which are key players in the climate system.     

Concentration effects in myoglobin-catalyzed peroxidation of linoleate

The concentration of the free fatty acid anion linoleate was found to be important for the pro-oxidative activity of metmyoglobin, MbFe(III), and for mixtures of metmyoglobin and hydrogen peroxide, MbFe(III)/H(2)O(2), to yield perferrylmyoglobin, (*)MbFe(IV)=O, whereas for ferrylmyoglobin, MbFe(IV)=O, no concentration effect was noted as studied in linoleate emulsions (pH 7.4 and 25 degrees C). Determination of conjugated dienes using second-derivative absorption spectroscopy, changes in Soret band absorbance, and spin-trapping ESR spectroscopy with alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) as the spin trap were used to evaluate the pro-oxidative activity of myoglobins. At a linoleate (LA)/heme protein (HP) ratio of 100, no MbFe(III)-induced linoleate peroxidation was observed, as MbFe(III) was converted to its non-pro-oxidative low-spin derivative, hemichrome, independently of the presence of H(2)O(2). At higher LA/HP ratios, linoleate peroxidation was initiated by the addition of MbFe(III), both in the presence and in the absence of H(2)O(2). This proceeded with denaturation of MbFe(III), as followed by changes in Soret absorption band, which most probably release or expose the heme group to the environment and thereby permit hematin-induced lipid peroxidation. The obtained results show that the mechanism by which MbFe(IV)=O initiates linoleate peroxidation is different from MbFe(III)- and MbFe(III)/H(2)O(2)-initiated linoleate peroxidation. The shift in mechanism between heme protein cleavage of lipid hydroperoxides and hematin-induced lipid peroxidation is discussed in relation to oxidative progress in biological systems and muscle-based foods.     

Photooxidative degradation of beer bittering principles: a key step on the route to lightstruck flavor formation in beer

Isohumulones, dihydroisohumulones, tetrahydroisohumulones, and humulinones, important hop-derived bittering compounds in beer, were shown to give rise to reactive triacylmethyl radicals on interaction with triplet-excited riboflavin after spin trapping by 5,5-dimethyl-1-pyrroline N-oxide or 2-methyl-2-nitrosopropane, followed by electron paramagentic resonance spectroscopy combined with spectral simulation. Electron abstraction from the ionized beta-tricarbonyl chromophore, which is common to all five-membered ring hop derivatives, is the initial event on photoinduced degradation. Radicaloid decomposition of isohumulones leads to precursors for 3-methylbut-2-ene-1-thiol, the lightstruck constituent in beer. Interaction of reduced derivatives of isohumulones with triplet-excited riboflavin furnished radical precursors of volatile aldehydes, which may lead to the development of unpleasant stale or cardboard flavors.     

Comparison of isolation methods for the determination of important aroma compounds in black currant (Ribes nigrum L.) juice, using nasal impact frequency profiling

The influence of isolation method on the determination of important aroma compounds in black currant juice was investigated by surface of nasal impact frequency (SNIF) gas chromatography-olfactometry (GC-O). The applied methods were solvent extraction, static headspace, and purge and trap using 15 and 60 min of purge time. By the four methods, a total of 59 odors were observed, and, of these, 44 corresponded to compounds that could be identified. For the headspace methods increasing purge volumes resulted in recoveries of additional, less volatile compounds. The main compound groups recovered by the headspace methods were esters and terpenes, whereas compounds recovered by solvent extraction were not as dominated by fruity odors. For most compounds there was agreement between the size of the SNIF value obtained by GC-O and the amount of the measurable compound found by gas chromatography-mass spectrometry.     

Clear-cutting affects the ammonia-oxidising community differently in limed and non-limed coniferous forest soils

The effects of clear-cutting on the ammonia-oxidising bacterial community were studied in the soil of limed and non-limed spruce forest plots located in the central part of southern Sweden. The communities were studied using denaturing gradient gel electrophoresis (DGGE) profiling after polymerase chain reaction (PCR) amplification from total DNA with primers reported to be specific for -subgroup ammonia-oxidising bacteria. The bands on the DGGE were sequenced and each unique sequence was interpreted as representing one ammonia-oxidising population. The relative abundance of each population was determined by measuring the fluorescence of the respective DGGE bands. In both limed and non-limed soil, the same two Nitrosospira populations were found, one belonging to cluster 2 (NScl2) and one to cluster 4 (NScl4). However, while NScl4 first appeared a year after the clear-cutting in the non-limed plot, it was present both before and after the cutting in the limed plot. Irrespective of previous liming, clear-cutting caused a shift in the ammonia-oxidiser community, from dominance by the NScl2 population to a community with approximately equal relative abundance of NScl2 and NScl4. In both plots the total size of the community increased after clear-cutting (based on increased DGGE band intensity), most likely due to increased NH₄⁺ availability, but the growth response was faster in the limed plot. Hence, the prior liming increased the responsiveness of the ammonia-oxidisers to the changes caused by cutting. This is the first study to report the effects of clear-cutting on the ammonia-oxidising community, and the results show a clear correlation between increased potential nitrification and a shift in the ammonia-oxidiser community.     

Reactivity of bovine whey proteins, peptides, and amino acids toward triplet riboflavin as studied by laser flash photolysis

The reaction between the triplet excited state of riboflavin and amino acids, peptides, and bovine whey proteins was investigated in aqueous solution in the pH range from 4 to 9 at 24 degrees C using nanosecond laser flash photolysis. Only tyrosine and tryptophan (and their peptides) were found to compete with oxygen in quenching the triplet state of riboflavin in aqueous solution, with second-order rate constants close to the diffusion limit, 1.75 x 10(9) and 1.40 x 10(9) L mol(-1) s(-1) for tyrosine and tryptophan, respectively, with beta-lactoglobulin and bovine serum albumin having comparable rate constants of 3.62 x 10(8) and 2.25 x 10(8) L mol(-1) s(-1), respectively. Tyrosine, tryptophan, and their peptides react with the photoexcited triplet state of riboflavin by electron transfer from the tyrosine and tryptophan moieties followed by a fast protonation of the resulting riboflavin anion rather than by direct H-atom abstraction, which could be monitored by time-resolved transient absorption spectroscopy as a decay of triplet riboflavin followed by a rise in riboflavin anion radical absorption. For cysteine- and thiol-containing peptides, second-order rate constants depend strongly on pH, for cysteine corresponding to pKaRSH = 8.35. H-atom abstraction seems to operate at low pH, which with rising pH gradually is replaced by electron transfer from the thiol anion. From the pH dependence of the second-order rate constant, the respective values for the H-atom abstraction (k = 1.64 x 10(6) L mol(-1) s(-1)) and for the electron transfer (k = 1.20 x 10(9) L mol(-1) s(-1)) were determined.     

The effect of protein source in late pregnancy feed on the occurrence of agalactia post partum in the sow

The effect of an all vegetable protein diet on the occurrence of agalacatia was studied. The experiment was performed in a commercial one thousand sow unit with an average frequency of agalactia of 50%. The all vegetable diet significantly reduced the rectal temperature 48 h post partum and the number of medical treatments required. The litter size at weaning was larger (p greater than 0.05) in the group on the all vegetable protein diet.     

Amino acid and protein scavenging of radicals generated by iron/hydroperoxide system: an electron spin resonance spin trapping study

Reduction of free radicals generated by Fe(II)/cumene-hydroperoxide (CumOOH) by amino acids (Gly, Cys, Met, His, and Trp) and proteins (bovine serum albumin (BSA), beta-lactoglobulin, and lactoferrin) was followed by electron spin resonance spectroscopy using alpha-phenyl-N-tert-butylnitrone (PBN), 2-methyl-2-nitrosopropane (MNP), and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin traps. The radical species detected were mostly carbon-centered radicals from CumOOH fragmentation (methyl/*H3 and ethyl/*H2CH3), although carbon-centered radicals originated from amino acids could be formed in the presence of Cys, Met, His, or Trp. All proteins and amino acids, except Cys, were effective at inhibiting generation of radicals from the Fe(II)/CumOOH system. Trp was the amino acid with the highest antiradical activity, followed by His > Gly approximately Met. Lactoferrin was the protein showing the most efficient inhibition of radical formation from the Fe(II)/CumOOH system, and BSA and beta-lactoglobulin were not significantly different in their antiradical activities. These results suggest that proteins with higher inhibitory activity on lipid oxidation promoted by transition metal catalytic decomposition of hydroperoxides should be those with elevated metal-chelating and radical-scavenging properties as well as low concentration and accessibility of reducing groups from amino acids capable of activating metals, such as sulfhydryl groups.     

Volatile monoterpenes in black currant (Ribes nigrum L.) juice: effects of heating and enzymatic treatment by beta-glucosidase

Changes of terpenes in black currant juice induced by the action of heat were investigated in the present study. Limonene, alpha-terpinene, linalool, alpha-terpineol, 4-terpineol, and menthol added to either black currant juice or a model system were thermally treated at 90 degrees C for 30 min. Similar heat-induced decreases in the concentration of the terpenes were observed in the two systems. The concentration of a range of terpene hydrocarbons and oxygenated terpenes increased, alpha-terpineol being a main conversion product of most of the examined compounds. In the main, the measured loss of compounds exceeded the detected concentrations of products formed. In addition, determination of glycosidically bound terpenes in the juice was carried out by two methods of enzymatic hydrolysis, namely, addition of beta-glucosidase to an Amberlite XAD-2 isolate or directly to black currant juice. The two methods gave the same patterns of seven released volatile aglyconic terpenes. However, none of the released terpenes are important for the odor of black currant juice.