Aldehyde-induced xanthine oxidase activity in raw milk

In the present study, the aldehyde-induced pro-oxidative activity of xanthine oxidase was followed in an accelerated raw milk system using spin-trap electron spin resonance (ESR) spectroscopy. The aldehydes acetaldehyde, propanal, hexanal, trans-2-hexenal, trans-2-heptenal, trans-2-nonenal, and 3-methyl-2-butenal were all found to initiate radical reactions when added to milk. Formation of superoxide through aldehyde-induced xanthine oxidase activity is suggested as the initial reaction, as all tested aldehydes were shown to trigger superoxide formation in an ultrahigh temperature (UHT) milk model system with added xanthine oxidase. It was found that addition of aldehydes to milk initially increased the ascorbyl radical concentration with a subsequent decay due to ascorbate depletion, which renders the formation of superoxide in milk with added aldehyde. The present study shows for the first time potential acceleration of oxidative events in milk through aldehyde-induced xanthine oxidase activity.     

A comparative study of three different methods for assessing fish communities in a small eutrophic lake

Sound decisions on the management of fish stocks depend on knowledge about the species composition, number, biomass and size structure of existing populations. Accordingly, the ability to make solid population estimates is essential. In this study, a 2.15 ha lake was completely drained and the total number of fish was recorded and amounted to 180,915 individuals divided into seven species having a total weight of 1,395 kg. Before the draining, three commonly used methods in fish surveys were applied: multi‐mesh gillnets, point abundance sampling by electrofishing (PASE) and mark–recapture. Following the determination of the actual number and size distribution of each species, we evaluated the efficiency of the methods and found that gillnets caught a relatively high number of species (five out of seven) and thus proved to be the best tool for mapping species richness. However, gillnets were size selective towards larger individuals of perch (Perca fluviatilis) and did not catch roach (Rutilus rutilus) <5 cm. In contrast to gillnets, PASE was very effective at catching YOY fish in the shore zone but selected for larger‐sized roach. In sum, gillnetting proved to be the most accurate method for estimating species composition, PASE also being useful. Overall, mark–recapture provided relatively good estimates of population size but small‐sized (<11 cm) roach proved not to be well suited for mark–recapture surveys. We conclude that the best method(s) surveying fish stocks depends on various factors such as target species, size distribution and the purpose of the survey.     

Bats and bees are pollinating Parkia biglobosa in The Gambia

A pollination experiment was conducted with Parkia biglobosa (Fabaceae) in The Gambia. P. biglobosa is integrated in the farming systems and produces fruit pulp and seeds used in cooking. The species is bat-pollinated, and in areas with few bats the main pollinators are assumed to be honey bees. A higher rate of effective pollination will in many instances increase fruit production, and the aim of this study was to investigate pollination efficiency of different pollinators. Access of flower visiting animals to flowers was controlled by nets with differently sized mesh, using five trees as replicates. The pollinators’ identity, efficiency, and relative effect were determined. Bats, honey bees, and stingless bees were able to pollinate the species. Bat-visited capitula produced more pods, but not significantly more than honey bees. Honey bees were more efficient than stingless bees, resulting in significantly less aborted seeds. The treatment which excluded all flower visitors developed no mature pods, indicating that P. biglobosa was not autonomous autogamous, apomictic, or parthenocarpic, while the treatment with confined honey bees showed that geitonogamy is possible. Sugar content of fruit pulp was analysed and a positive correlation between number of seeds per pod and the sugar content was found. Improved pollination success may thus result in sweeter fruits. We conclude it is important to strive against a pollinator-friendly environment in order to attract bats and bees. Furthermore, we suggest beekeeping in the vicinity of P. biglobosa as a way to increase yield.     

Genetic analysis of Trichuris suis and Trichuris trichiura recovered from humans and pigs in a sympatric setting in Uganda

The whipworms Trichuris trichiura and Trichuris suis in humans and pigs, respectively, are believed to be two different species yet closely related. Morphologically, adult worms, eggs and larvae of the two species are indistinguishable. The aim of this study was to examine the genetic variation of Trichuris sp. mainly recovered from natural infected pigs and humans. Worm material isolated from humans and pigs living in the same geographical region in Uganda were analyzed by PCR, cloning and sequencing. Measurements of morphometric characters were also performed. The analysis of the ITS-2 (internal transcribed spacer) region showed a high genetic variation in the human-derived worms with two sequence types, designated type 1 and type 2, differing with up to 45%, the type 2 being identical to the sequence found in pig-derived worms. A single human-derived worm showed exclusively the type 2-genotype (T. suis-type) and three cases of 'heterozygote' worms in humans were identified. However, the analysis showed that sympatric Trichuris primarily assorted with host origin. Sequence analysis of a part of the genetically conserved β-tubulin gene confirmed two separate populations/species but also showed that the 'heterozygote' worms had a T. suis-like β-tubulin gene. A PCR-RFLP on the ITS-2 region was developed, that could distinguish between worms of the pig, human and 'heterozygote' type. The data suggest that Trichuris in pigs and humans belong to two different populations (i.e. are two different species). However, the data presented also suggest that cross-infections of humans with T. suis takes place. Further studies on sympatric Trichuris populations are highly warranted in order to explore transmission dynamics and unravel the zoonotic potential of T. suis.     

Cerebral state monitoring in Beagle dogs sedated with medetomidine

OBJECTIVE: To provide experience of monitoring the level of hypnosis with the Cerebral State Monitor (CSM), a device extracting a single numerical variable between 0 and 100 from the electroencephalogram in dogs sedated with medetomidine during dental scale removal. STUDY DESIGN: Prospective observational study. Animals Nine female Beagle dogs weighing 13.3 +/- 1.3 kg. METHODS: Cerebral state index (CSI) and burst suppression ratio (BSR) were recorded from sub-dermal needle electrodes in dogs sedated after subcutaneous injection of 114 +/- 11 microg kg(-1) medetomidine. Ten minutes after injection CSI monitoring began, and after 5 minutes, dental scale removal with an ultrasonic probe was started. After approximately 30 minutes, the effects of medetomidine were antagonized with atipamezole. RESULTS: The CSI had a median value of 43 (range 40-56) in undisturbed sedated dogs. During dental scale removal, CSI increased to a median value of 99 (range 92-100). The BSR in undisturbed sedated dogs ranged from 2 to 15, but fell to zero during dental scale removal. CONCLUSIONS: Stimulation during dental scale removal might be expected to reduce the level of sedation and hypnosis in dogs to which medetomidine had been administered. The concurrent increase in CSI and decrease in BSR suggested that a higher CSI was associated with arousal from sedation and a reduction in the depth of hypnosis. More studies are needed to validate CSI in order to better understand the functioning of this monitor. CLINICAL RELEVANCE: The CSM shows promise for monitoring the degree of sedation and hypnosis during anaesthesia, and after adequate validation, could contribute to the refinement of anaesthetic techniques in animals.     

CO/FT regulatory module controls timing of flowering and seasonal growth cessation in trees

Forest trees display a perennial growth behavior characterized by a multiple-year delay in flowering and, in temperate regions, an annual cycling between growth and dormancy. We show here that the CO/FT regulatory module, which controls flowering time in response to variations in daylength in annual plants, controls flowering in aspen trees. Unexpectedly, however, it also controls the short-day-induced growth cessation and bud set occurring in the fall. This regulatory mechanism can explain the ecogenetic variation in a highly adaptive trait: the critical daylength for growth cessation displayed by aspen trees sampled across a latitudinal gradient spanning northern Europe.     

Light-induced oxidation in semihard cheeses. Evaluation of methods used to determine levels of oxidation

Light-induced oxidation in Havarti cheese (38% fat) stored in the dark and exposed to fluorescent light was evaluated by an array of chemical, physical, and spectroscopic methods. Light-induced changes were noticeable already after short exposure times (<12 h). A clear differentiation between samples stored in the dark and samples exposed to 1000 lx fluorescent light was obtained by means of the following methods: color measurements (a values), peroxide value determinations, and evaluations of volatile oxidation products by solid-phase microextraction gas chromatography (SPME-GC). The expected changes in peroxide values in relation to storage time were not evident. Measuring free radicals by electron spin resonance spectrometry could not be done to distinguish between samples, possibly due to the conversion of radicals during sample preparation. However, significant light-exposure effects on secondary oxidation products, detected by SPME-GC, were noted for 1-pentanol, 1-hexanol, nonanal, and benzaldehyde.     

Conservation of epiphytic lichens: Significance of remnant aspen (Populus tremula) trees in clear-cuts

In the boreal forest landscape, aspen has been effectively selected against in favour of conifers. The decrease in aspen is of particular concern since it has more host-specific species associated with it than any other boreal tree species. Recently forest management systems have begun to include green-tree retention in order to maintain structural diversity. We initiated this study in order to investigate whether retained aspen trees provide suitable habitats for epiphytic lichens and, if so, whether this varies according to species characteristics, such as morphology and photobiont. We chose to investigate the abundance and vitality of five species: three foliose cyanobacterial lichens (Collema curtisporum, Collema furfuraceum and Leptogium saturninum) and two crustose green-algal lichens (Biatora epixanthoides and Mycobilimbia carneoalbida). These lichens were examined on aspen within forest stands and on remnant aspen in clear-cuts at eight localities, in northern Sweden. Our results show that the response to exposure following clear-felling differs between species according to their morphology. The two crustose lichens were more abundant in the forest stands compared to the clear-cuts. In the clear-cuts, they mainly occurred on the northern sides of the trunks. Even 24 years after cutting, the three cyanolichens were equally or even more abundant on trees in the clear-cuts than in the forest stands. However, they were mainly found on the northern sides of the remnant aspen. We suggest that remnant aspen trees may function as suitable substrate and as stepping stones for colonisation of new stands, at least for the cyanolichens studied here.     

Gardens benefit bees and enhance pollination in intensively managed farmland

The recent loss of pollinating insects and out-crossing plants in agricultural landscapes has raised concern for the maintenance of ecosystem services. Wild bees have been shown to benefit from garden habitats in urban and suburban areas. We investigated the effects of distance from garden habitats on wild bees and seed set of a native out-crossing plant Campanula persicifolia, in intensively managed agricultural landscapes in Southern Sweden. Bee abundance and species richness, as well as plant seed set, were higher closer to gardens (<15 m) than further away (>140 m). This highlights private gardens as a landscape wide resource for pollinators but also the lack of sufficient pollination of wild plants in contemporary agricultural landscapes.