Paternal attractiveness and the effects of differential allocation of parental investment

The differential allocation hypothesis (DAH) predicts that an individual should vary its reproductive investment according to the attractiveness of its mate. A recently revised version of the DAH makes explicit that investment can be positive, i.e. higher for the offspring of attractive males which should be of higher quality, or negative, i.e. higher for offspring of unattractive males, for example compensating for inheriting poor paternal genes. Moreover, investment can be made by the father and the mother. Here, we tested whether experimental manipulation of male attractiveness affected parental investment at different reproductive stages and thus influenced fitness-related traits in offspring. In two aviaries, all male zebra finches, Taeniopygia guttata, were given red leg rings to increase attractiveness and in two aviaries all males received green leg rings to decrease attractiveness. This controlled for assortative mating between treatments. Ring colour was merely an experimental manipulation of male attractiveness, not paternal quality, so we might expect additional investment to elevate offspring quality. Eggs were cross-fostered between and within treatments to allow differentiation of effects of investment in eggs and nestlings. Clutch and brood sizes were standardized. Both positive and negative investment were observed: Eggs from red-ringed fathers had higher yolk to albumen ratios than eggs from green-ringed fathers. Nestlings from eggs laid and incubated by parents in the red-ringed group had higher hatching masses than those in the green-ringed group. Both parents in the green-ringed group fed nestlings more frequently than red-ringed parents. Offspring performance was influenced by the treatment of both foster and biological parents, but combined effects of these different investment patterns on fitness-related traits were ambiguous. Male attractiveness appeared to affect patterns of reproductive investment but not consistently across all forms of reproductive investment suggesting that the costs and benefits of differential allocation vary among individuals and across contexts

Tyrosine Kinase Syk Non-Enzymatic Inhibitors and Potential Anti-Allergic Drug-Like Compounds Discovered by Virtual and In Vitro Screening

In the past decade, the spleen tyrosine kinase (Syk) has shown a high potential for the discovery of new treatments for inflammatory and autoimmune disorders. Pharmacological inhibitors of Syk catalytic site bearing therapeutic potential have been developed, with however limited specificity towards Syk. To address this topic, we opted for the design of drug-like compounds that could impede the interaction of Syk with its cellular partners while maintaining an active kinase protein. To achieve this challenging task, we used the powerful potential of intracellular antibodies for the modulation of cellular functions in vivo, combined to structure-based in silico screening. In our previous studies, we reported the anti-allergic properties of the intracellular antibody G4G11. With the aim of finding functional mimics of G4G11, we developed an Antibody Displacement Assay and we isolated the drug-like compound C-13, with promising in vivo anti-allergic activity. The likely binding cavity of this compound is located at the close vicinity of G4G11 epitope, far away from the catalytic site of Syk. Here we report the virtual screen of a collection of 500,000 molecules against this new cavity, which led to the isolation of 1000 compounds subsequently evaluated for their in vitro inhibitory effects using the Antibody Displacement Assay. Eighty five compounds were selected and evaluated for their ability to inhibit the liberation of allergic mediators from mast cells. Among them, 10 compounds inhibited degranulation with IC50 values ≤10 µM. The most bioactive compounds combine biological activity, significant inhibition of antibody binding and strong affinity for Syk. Moreover, these molecules show a good potential for oral bioavailability and are not kinase catalytic site inhibitors. These bioactive compounds could be used as starting points for the development of new classes of non-enzymatic inhibitors of Syk and for drug discovery endeavour in the field of inflammation related disorders

Maternal effects in the highly communal sociable weaver may exacerbate brood reduction and prepare offspring for a competitive social environment

<p>Maternal effects can influence offspring phenotype with short- and long-term consequences. Yet, how the social environment may influence egg composition is not well understood. Here, we investigate how laying order and social environment predict maternal effects in the sociable weaver, Philetairus socius, a species that lives in massive communal nests which may be occupied by only a few to 100+ individuals in a single nest. This range of social environments is associated with variation in a number of phenotypic and life-history traits. We investigate whether maternal effects are adjusted accordingly. We found no evidence for the prediction that females might benefit from modifying brood hierarchies through an increased deposition of androgens with laying order. Instead, females appear to exacerbate brood reduction by decreasing the costly production of yolk mass and antioxidants with laying order. Additionally, we found that this effect did not depend on colony size. Finally, in accordance with an expected increased intensity of environmental stress with increasing colony size, we found that yolk androgen concentration increased with colony size. This result suggests that females may enhance the competitive ability of offspring raised in larger colonies, possibly preparing the offspring for a competitive social environment.</p>