Molecular biomonitoring of a population of nurses handling antineoplastic drugs

Many antineoplastic drugs have been found to have carcinogenic, mutagenic and teratogenic activity and so hospital personnel handling these substances are potentially exposed to health risk. Understanding this risk derived from protracted occupational exposure has great relevance even if the workers normally adopt individual and environmental protective measures. To address this question we have studied the presence of DNA and chromosome damage in a population of nurses employed in Italian oncology units and in matched controls. We used the comet assay to evidence the presence of DNA strand breaks, due to both acute and chronic exposure, and the micronucleus (MN) test, which is a measure of clastogenic and aneugenic events. Furthermore, since the individual response to the exogenous insults may be genetically determined, we studied the possible influence of single nucleotide polymorphism in XRCC1 and XRCC3 DNA repair genes on induced genetic damage. We also considered the effects of confounding factors like smoking, age and gender. The results indicated that the exposed subjects had significantly high levels of genetic damage. Age and gender were associated with increased values in MN, both in control and in exposed groups; the smoking habit affects MN frequency in controls, but not in workers. Furthermore we found that exposed subjects bearing at least one XRCC1 variant allele (399Gln) show higher values of MN. The present data provide the evidence to show that occupational exposure to antineoplastic drugs, even if in safety controlled conditions, represents a serious health risk. Furthermore we have shown that the presence of XRCC1 genetic polymorphism could contribute to increase the genetic damage in susceptible individuals who are occupationally exposed to dangerous substances.     

Don't forget to look down – collaborative approaches to predator conservation

Finding effective ways of conserving large carnivores is widely recognised as a priority in conservation. However, there is disagreement about the most effective way to do this, with some favouring top‐down ‘command and control’ approaches and others favouring collaboration. Arguments for coercive top‐down approaches have been presented elsewhere; here we present arguments for collaboration. In many parts of the developed world, flexibility of approach is built into the legislation, so that conservation objectives are balanced with other legitimate goals. In the developing world, limited resources, poverty and weak governance mean that collaborative approaches are likely to play a particularly important part in carnivore conservation. In general, coercive policies may lead to the deterioration of political legitimacy and potentially to non‐compliance issues such as illegal killing, whereas collaborative approaches may lead to psychological ownership, enhanced trust, learning, and better social outcomes. Sustainable hunting/trapping plays a crucial part in the conservation and management of many large carnivores. There are many different models for how to conserve carnivores effectively across the world, research is now required to reduce uncertainty and examine the effectiveness of these approaches in different contexts.     

Mass‐dependent reproductive strategies in wild bighorn ewes: a quantitative genetic approach

In the Ram Mountain bighorn sheep (Ovis canadensis) population, ewes differing by more than 30% in body mass weaned lambs with an average mass difference of only 3%. Variability in adult body mass was partly due to additive genetic effects, but inheritance of weaning mass was weak. Maternal effects could obscure genetic effects in the phenotypic expression of weaning mass, particularly if they reflected strategies of maternal expenditure that varied according to ewe mass. We performed a quantitative genetic analysis to assess genetic and environmental influences on ewe mass and on maternal expenditure. We used the mean daughters/mother regression method and Derivative Free Restricted Maximum Likelihood models to estimate heritability (h²) of ewe mass and indices of maternal expenditure. We found additive genetic effects on phenotypic variation in maternal mass, in lamb mass at weaning (absolute maternal expenditure) and in weaning mass relative to maternal mass at weaning (relative maternal expenditure). Heritability suggests that maternal expenditure has the potential to evolve. The genetic correlation of ewe mass and absolute maternal expenditure was weak, while ewe mass and relative maternal expenditure were strongly negatively correlated. These results suggest additive genetic effects on mass‐dependent reproductive strategies in bighorn ewes. Mass‐dependent reproductive strategies could affect lamb survival and phenotypic variation in adult mass. As population density increased and reproduction became costlier, small females reduced maternal expenditure more than large females. Constraints on reproductive strategy imposed by variations in resource availability are therefore likely to differ according to ewe mass. A general trend for a decrease in maternal expenditure relative to maternal size in mammals suggests that size‐dependent negative maternal effects may be common.     

Expression of high- and low-affinity epidermal growth factor receptors in human hepatoma cell lines

Data are presented from a comparative research on expression of epidermal growth factor (EGF) receptors and response to EGF of six independently established cell lines derived from human hepatoma. These lines differ in terms of the degree of differentiation, presence of hepatitis B virus (HBV) DNA copies in integrated form and expression of HBV genes. Our results indicate differential expression of membrane EGF receptors and differential response to EGF under serum- and hormone-free culture conditions. Furthermore, a significant difference in affinity could be detected between EGF receptors of the two highly dedifferentiated cell lines (HA22T/VGH and Li7A) whose replication is inhibited by EGF concentrations capable of stimulating more differentiated phenotypes.     

Sucrose Breakdown in Relation to Fruit Growth of Acid Lime (Citrus aurantifolia)

The physiological capacity for sucrose breakdown in developingjuice sac cells of acid limes was estimated by assaying theactivity of the three enzymes of sucrose catabolism in additionto vacuolar acid hydrolysis. The maximum potential rates ofsucrose breakdown were compared with the observed rates of carbonutilization. Highest potential rates of sucrose breakdown (28.621mmol cm^–3 per hydrated active space d^–1) occurredat the initial stages of fruit development where carbon utilizationwas highest. As the fruit developed, the potential rates ofsucrose breakdown and carbon utilization declined to very lowlevels. At 80% of development, vacuolar acid hydrolysis becamethe only physiological mechanism for sucrose breakdown. Therelatively low amounts of sucrose hydrolysed by acid hydrolysisat this time were just sufficient to account for the measuredcarbon demands. The results suggest that carbon supplied bythis distinct sucrose catabolizing system is able to provideadequate levels of carbon skeletons for the observed levelsof respiration and dry weight deposition early in development,but becomes a limiting factor for growth in the later stages. Key words: Vacuolar acid hydrolysis, Citrus aurantifolia     

A quantitative trait locus analysis of personality in wild bighorn sheep

Personality, the presence of persistent behav105 ioral differences among individuals over time or contexts, potentially has important ecological and evolutionary consequences. However, a lack of knowledge about its genetic architecture limits our ability to understand its origin, evolution, and maintenance. Here, we report on a genome‐wide quantitative trait locus (QTL) analysis for two personality traits, docility and boldness, in free‐living female bighorn sheep from Ram Mountain, Alberta, Canada. Our variance component linkage analysis based on 238 microsatellite loci genotyped in 310 pedigreed individuals identified suggestive docility and boldness QTL on sheep chromosome 2 and 6, respectively. A lack of QTL overlap indicated that genetic covariance between traits was not modulated by pleiotropic effects at a major locus and may instead result from linkage disequilibrium or pleiotropic effects at QTL of small effects. To our knowledge, this study represents the first attempt to dissect the genetic architecture of personality in a free‐living wildlife population, an important step toward understanding the link between molecular genetic variation in personality and fitness and the evolutionary processes maintaining this variation.     

Can phenotypic rescue from harvest refuges buffer wild sheep from selective hunting?

Human harvests can unwittingly drive evolution on morphology and life history, and these selective effects may be detrimental to the management of natural resources. Although theory suggests that harvest refuges, as sources of unselected animals, could buffer the effects of human exploitation on wild populations, few studies have assessed their efficiency. We analyzed records from >7000 trophy bighorn rams (Ovis canadensis) harvested in Alberta, Canada, between 1974 and 2011 to investigate if the movement of rams from refuges toward harvested areas reduced the effects of selective harvesting on horn size through phenotypic rescue. Rams taken near refuges had horns on average about 3% longer than rams shot far from refuges and were slightly older, suggesting migration from refuges into hunted areas. Rams from areas adjacent to and far from harvest refuges, however, showed similar declines in horn length and increases in age at harvest over time, indicating a decreasing rate of horn growth. Our study suggests that the influx of rams from refuges is not sufficient to mitigate the selective effects of sheep trophy harvest. Instead, we suggest that selective hunting of highly mobile animals may affect the genetic structure of populations that spend part of the year inside protected areas.