A study on in vitro glycation processes by matrix-assisted laser desorption ionization mass spectrometry

The number of glucose molecules condensed on glycated bovine serum albumin have been easily determined by means of matrix-assisted laser desorption/ionization mass spectrometry. Measurements were carried out on samples from incubation of the proteins with glucose at different concentrations (0.02 M, 0.2 M, 2 M and 5 M). A clear increase in molecular mass of BSA with respect to incubation time is detected. In contrast to what is observed with fluorescence, the plots of molecular mass increase vs. incubation time show tha occurrence of a steady state, corresponding to the complete saturation of all the protein sites against glucose. Comparison of fluorescence and molecular mass data reveals that some further reactions, different from condensation, must take place, which could be in principle either intramolecular or originated by reactivity of modified condensed gluocse moieties vs. free glucose.     

New Approach to Develop Optimized Sunscreens that Enable Cutaneous Vitamin D Formation with Minimal Erythema Risk

Sunscreens protect the skin against erythemal radiation (E_er). But at the same time they reduce the effective radiation dose (E_VD) responsible for the formation of previtamin D in the skin. The paper describes a calculation method for optimizing the ratio E_VD/E_er behind sunscreens e.g. with SPF 5, 15 and 30 respectively. Taking into account that a majority of people in industrialized countries suffer from a shortage in vitamin D even in summer time, the ratio E_vd/E_er is a new and important criterion for the quality of sunscreens. Furthermore the exposure time t_vd needed per day for forming the equivalent of the recommended amount of 2000 IU of vitamin D per day for skin type 2 is estimated when sunscreens with different filter compositions are used. In vitro experiments show a significant increase of the conversion of 7-dehydrocholesterol (7-DHC) to previtamin D when exposed to artificial solar radiation behind an experimental sunscreen optimized for previtamin D production compared to a commercial sunscreen having the same SPF.     

Gender Differentiated Preferences for a Community-Based Conservation Initiative

Community-based conservation (CBC) aims to benefit local people as well as to achieve conservation goals, but has been criticised for taking a simplistic view of “community” and failing to recognise differences in the preferences and motivations of community members. We explore this heterogeneity in the context of Kenya’s conservancies, focussing on the livelihood preferences of men and women living adjacent to the Maasai Mara National Reserve. Using a discrete choice experiment we quantify the preferences of local community members for key components of their livelihoods and conservancy design, differentiating between men and women and existing conservancy members and non-members. While Maasai preference for pastoralism remains strong, non-livestock-based livelihood activities are also highly valued and there was substantial differentiation in preferences between individuals. Involvement with conservancies was generally perceived to be positive, but only if households were able to retain some land for other purposes. Women placed greater value on conservancy membership, but substantially less value on wage income, while existing conservancy members valued both conservancy membership and livestock more highly than did non-members. Our findings suggest that conservancies can make a positive contribution to livelihoods, but care must be taken to ensure that they do not unintentionally disadvantage any groups. We argue that conservation should pay greater attention to individual-level differences in preferences when designing interventions in order to achieve fairer and more sustainable outcomes for members of local communities.     

The role of the carbohydrate moiety in the biologic properties of fibrinogen

The carbohydrate moiety of some glycoproteins influences their secretion and functional properties. We have examined the importance of the oligosaccharide chains of fibrinogen in this regard. Fibrinogen was labeled de novo by the addition to rabbit hepatocyte monolayer cultures of either 3H-amino-acids or [2-3H] mannose, in the presence or absence of tunicamycin, a potent inhibitor of glycosylation. Inhibition of glycosylation, which ranged from 75 to 80%, was determined by incorporation of [2-3H]mannose as quantitated by gel filtration. Synthesis and secretion of fibrinogen were quantitated by 3H-amino-acid incorporation, using anti-fibrinogen immunoaffinity column chromatography of medium and cell homogenates. Tunicamycin did not appreciably inhibit fibrinogen synthesis, as compared to a 30-40% inhibition of overall protein synthesis, determined by incorporation of 3H-amino-acids into trichloroacetic acid-precipitable material. There was no evidence that secretion of fibrinogen was impaired. Fibrinogen from medium was copurified by adding cold plasma fibrinogen as carrier. Nonglycosylated fibrinogen was found to be functional as demonstrated by incorporation of radioactivity into clots of the copurified material at a rate identical to that of glycosylated fibrinogen. When clotted in the presence of Ca2+ and Factor XIII, cross-linking of glycosylated and nonglycosylated fibrin was demonstrable on fluorography of sodium dodecyl sulfate-polyacrylamide gels, showing disappearance of gamma-chain and appearance of gamma-gamma-dimers.     

An independent validation study of loci associated with nematode resistance in sheep

Gastrointestinal nematode infection is a constraint on sheep production worldwide. Selective breeding programmes to enhance resistance to nematode infection are currently being implemented in a number of countries. Identification of loci associated with resistance to infection or causative mutations for resistance would enable more effective selection. Loci associated with indicator traits for nematode resistance has been identified in previous studies. In this study, Scottish Blackface, Texel and Suffolk lambs were used to validate the effects at eight genomic regions previously associated with nematode resistance (OAR3, 4, 5, 7, 12, 13, 14, 21). No SNP was significantly associated with nematode resistance at the region‐wide level but seven SNPs in three of the regions (OAR4, 12, 14) were nominally associated with trichostrongyle egg count in this study and six of these were also significant when fitted as single SNP effects. Nematodirus egg count was nominally associated with SNPs on OAR3, 4, 7 and 12.     

Declining old‐forest species as a legacy of large trees lost

Aim

Global declines in large old trees from selective logging have degraded old‐forest ecosystems, which could lead to delayed declines or losses of old‐forest‐associated wildlife populations (i.e., extinction debt). We applied the declining population paradigm and explored potential evidence for extinction debt in an old‐forest dependent species across landscapes with different histories of large tree logging.

Location

Montane forests of the Sierra Nevada, California, USA.

Methods

We tested hypotheses about the influence of forest structure on territory extinction dynamics of the spotted owl (Strix occidentalis) using detection/non‐detection data from 1993 to 2011 across two land tenures: national forests, which experienced extensive large tree logging over the past century, and national parks, which did not.

Results

Large tree/high canopy cover forest was the best predictor of extinction rates and explained 26%–77% of model deviance. Owl territories with more large tree/high canopy cover forest had lower extinction rates, and this forest type was ~4 times more prevalent within owl territories in national parks ( = 19% of territory) than national forests ( = 4% of territory). As such, predicted extinction probability for an average owl territory was ~2.5 times greater in national forests than national parks, where occupancy was declining () and stable (), respectively. Large tree/high canopy cover forest remained consistently low, but did not decline, during the study period on national forests while owl declines were ongoing—an observation consistent with an extinction debt.

Main conclusions

In identifying a linkage between large trees and spotted owl dynamics at a regional scale, we provide evidence suggesting past logging of large old trees may have contributed to contemporary declines in an old‐forest species. Strengthening protections for remaining large old trees and promoting their recruitment in the future will be critical for biodiversity conservation in the world's forests.