Effect of combination of high-intensity ultrasound treatment and dextran glycosylation on structural and interfacial properties of buckwheat protein isolates

This study investigated the effects of high-intensity ultrasound and glycosylation on the structural and interfacial properties of the Maillard reaction conjugates of buckwheat protein isolate (BPI). The covalent attachment of dextran to BPI was confirmed by examination of the Fourier-transform infrared spectra. Emulsifying properties of the conjugates obtained by ultrasound treatment were improved as compared to those obtained by classical heating. Structural feature analyses suggested that conjugates obtained by ultrasound treatment had less α-helix and more random coil, higher surface hydrophobicity and less compact tertiary structure as compared to those obtained by classical heating. The surface activity measurement revealed that the BPI–dextran conjugates obtained by ultrasound treatment were closely packed and that each molecule occupied a small area of the interface. Combination of ultrasonic treatment and glycosylation was proved to be an efficient way to develop new stabilizers and thickening agents for food in this study.     

Selection analysis on the rapid evolution of a secondary sexual trait

Evolutionary analyses of population translocations (experimental or accidental) have been important in demonstrating speed of evolution because they subject organisms to abrupt environmental changes that create an episode of selection. However, the strength of selection in such studies is rarely measured, limiting our understanding of the evolutionary process. This contrasts with long-term, mark–recapture studies of unmanipulated populations that measure selection directly, yet rarely reveal evolutionary change. Here, we present a study of experimental evolution of male colour in Trinidadian guppies where we tracked both evolutionary change and individual-based measures of selection. Guppies were translocated from a predator-rich to a low-predation environment within the same stream system. We used a combination of common garden experiments and monthly sampling of individuals to measure the phenotypic and genetic divergence of male coloration between ancestral and derived fish. Results show rapid evolutionary increases in orange coloration in both populations (1 year or three generations), replicating the results of previous studies. Unlike previous studies, we linked this evolution to an individual-based analysis of selection. By quantifying individual reproductive success and survival, we show, for the first time, that males with more orange and black pigment have higher reproductive success, but males with more black pigment also have higher risk of mortality. The net effect of selection is thus an advantage of orange but not black coloration, as reflected in the evolutionary response. This highlights the importance of considering all components of fitness when understanding the evolution of sexually selected traits in the wild.     

Effect of cocaine and morphine on neutral endopeptidase activity of human peripheral blood mononuclear cells cultured with lectins

We have tested the effect of alkaloids (cocaine, morphine) and enkephalins on neutral endopeptidase of peripheral blood mononuclear cells activated by lectins. When treated with concanavalin A and cocaine, peripheral blood mononuclear cells showed an enhanced activity (+110 per cent) of the membrane neutral endopeptidase, which was not related to the expression of the common acute lymphoblastic leukemia antigen at the cell surface, although both molecules have the identical amino acid sequence. Phytohemagglutinin-P, morphine and synthetic enkephalins did not induce the activity of neutral endopeptidase nor the expression of common acute lymphoblastic leukemia antigen. Our findings suggested that the drugs of abuse, cocaine and morphine, affected specific membrane constituents without altering proliferation, subcellular localization of membrane enzymes or the surface immune phenotype of peripheral blood mononuclear cells.     

Pollination efficiency and reproductive patterns in relation to local plant density,population size,and floral display in the rewarding Listera ovata (Orchidaceae)

Pollination efficiency and reproductive success vary strongly among populations of most animal‐pollinated plant species, depending on their size and local density, whereas individual plants within populations experience varying levels of reproductive output as a result of differences in floral display. Although most orchid species have been shown to be severely pollination limited, few studies have investigated the impact of the above‐mentioned factors on pollination success and reproduction, especially in rewarding species. In this study, the impact of population size, local density of flowering plants, and floral display on the rates of pollinia export and fruit production was investigated in 13 natural populations of the rewarding terrestrial orchid Listera ovata. In addition, an emasculation experiment was set up to examine how floral display and local density of flowering plants affected the relative importance of cross‐ vs. geitonogamous pollination in determining fruit set. In the studied populations, pollination efficiency, pollen removal, and fruit set increased with increasing population size until a threshold value of 30–40 flowering plants was reached, above which pollination efficiency and reproductive output decreased again. On average, plants with large floral displays showed higher proportional pollinia removal and fruit set compared with smaller plants. Fruit production was also significantly and positively related to local plant density, whereas emasculation did not affect the relationship between local plant density and fruit set, suggesting that geitonogamous pollination did not affect the outcome of female function. The results of this study are discussed in the light of the flowering mechanism of the species and its generalized pollination system. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 713–721.     

Structural principles for the propeller assembly of beta-sheets: the preference for seven-fold symmetry.

Twisted beta-sheets, packed face to face, may be arranged in circular formation like blades of a propeller or turbine. This beta-propeller fold has been found in three proteins: that in neuraminidase consists of six beta-sheets while those in methylamine dehydrogenase and galactose oxidase are composed of seven beta-sheets. A model for multisheet packing in the beta-propeller fold is proposed. This model gives both geometrical parameters of the beta-propellers composed of different numbers of sheets and patterns of residue packing at their sheet-to-sheet interfaces. All the known beta-propeller structures have been analyzed, and the observed geometries and residue packing are found to be in good agreement with those predicted by models. It is shown that unusual seven-fold symmetry is preferable to six- or eight-fold symmetry for propeller-like multi-sheet assembly. According to the model, a six-beta-sheet propeller has to have predominantly small residues in the beta-strands closed to its six-fold axis, but no strong sequence constraints are necessary for a seven-fold beta-propeller.     

Common Loon Survival Rates and Mercury in New England and Wisconsin

Abstract: Bioaccumulation of toxic environmental mercury may affect the vital rates of piscivores such as the common loon (Gavia immer). Although immediate effects of mercury on early development or reproduction can be determined from short-term field studies or dosing experiments, long-term effects on survival for a long-lived species such as the common loon must be discerned from large, long-term observational data sets. We analyzed band-resight and mercury data for 776 adult loons in Wisconsin and New England, USA, from 1991 to 2001 to 1) estimate annual survival rates and 2) investigate the relation between mercury exposure and survival. The model-averaged estimate of apparent survival was 0.87, whereas the approximate survival rate (accounting for movement) was 0.92. We found no differences in apparent survival by geographic location or sex and no relation between survival and mercury. Power analyses showed that we were only likely to detect differences in survival ≥3%. Small differences in survival (<3%), which may be important to loon population viability, were unlikely to be detected in our dataset. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):665–673; 2008)     

Phylogenetic analyses of primate size evolution: the consequences of sexual selection

We have analysed the relationship between primate mating system, size and size dimorphism by utilizing several phylogenetically based methods. An independent contrast analysis of male and female size (log weight) showed that these are tightly correlated and that size dimorphism is not a simple allometric function of size. We found no relationship between mating system and sexual dimorphism in strepsirhines but a strong relationship in haplorhines. By matched-pairs analysis, where sister groups were matched according to whether the mating system predicted higher or lower intrasexual selection for male size, haplorhine species in more polygynous clades (with a predicted higher sexual selection) were significantly more dimorphic, had larger males, and also, but to a lesser degree, larger females. Both independent contrast and matched-pairs analyses are non-directional and correlational. By using a directional test we investigated how a transition in mating system affects size and dimorphism. Here, each observation is the sum of changes in dimorphism or size in a clade that is defined by a common origin of a mating system. Generally, dimorphism, as well as male and female size, increased after an expected increase in sexual selection, and decreased after an expected decrease in sexual selection. The pattern was, however, not significant for all of the alternative character reconstructions. In clades with an expected increase in sexual selection, male size increased more than female size. This pattern was significant for all character reconstructions. The directional investigation indicates that the magnitude of change in haplorhine dimorphism is larger after an increase in sexual selection than after a decrease, and, for some reconstructions, that the magnitude of size increase is larger than the magnitude of size decrease for both sexes. Possible reasons for these patterns are discussed, as well as their implications as being one possible mechanism behind Cope's rule, i.e. general size increase in many phylogenetic lineages.     

Accounting for female space sharing in St. Kilda Soay sheep (Ovis aries) results in little change in heritability estimates

When estimating heritability in free‐living populations, it is common practice to account for common environment effects, because of their potential to generate phenotypic covariance among relatives thereby biasing heritability estimates. In quantitative genetic studies of natural populations, however, philopatry, which results in relatives being clustered in space, is rarely accounted for. The two studies that have been carried out so far suggest absolute declines in heritability estimates of up to 43% when accounting for space sharing by relatives. However, due to methodological limitations these estimates may not be representative. We used data from the St. Kilda Soay sheep population to estimate heritabilities with and without accounting for space sharing for five traits for which there is evidence for additive genetic variance (birthweight, birth date, lamb August weight, and female post‐mortem jaw and metacarpal length). We accounted for space sharing by related females by separately incorporating spatial autocorrelation, and a home range similarity matrix. Although these terms accounted for up to 18% of the variance in these traits, heritability estimates were only reduced by up to 7%. Our results suggest that the bias caused by not accounting for space sharing may be lower than previously thought. This suggests that philopatry does not inevitably lead to a large bias if space sharing by relatives is not accounted for. We hope our work stimulates researchers to model shared space when relatives in their study population share space, as doing so will enable us to better understand when bias may be of particular concern.