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The expression in females of ornaments thought to be the target of sexual selection in males is a long-standing puzzle. Two main hypotheses are proposed to account for the existence of conspicuous ornaments in both sexes (mutual ornamentation): genetic correlation between the sexes and sexual selection on females as well as males. We examined the pattern of ornament gains and losses in 240 species of dragon lizards (Agamidae) in order to elucidate the relative contribution of these two factors in the evolution of mutual ornamentation. In addition, we tested whether the type of shelter used by lizards to avoid predators predicts the evolutionary loss or constraint of ornament expression. We found evidence that the origin of female ornaments is broadly consistent with the predictions of the genetic correlation hypothesis. Ornaments appear congruently in both sexes with some lineages subsequently evolving male biased sexual dimorphism, apparently through the process of natural selection for reduced ornamentation in females. Nevertheless, ornaments have also frequently evolved in both sexes independently. This suggests that genetic correlations are potentially weak for several lineages and sexual selection on females is responsible for at least some evolutionary change in this group. Unexpectedly, we found that the evolutionary loss of some ornaments is concentrated more in males than females and this trend cannot be fully explained by our measures of natural selection.

ObjectiveTo assess the relative escape force of human epididymal sperm using a laser generated optical trap and compare it with that of human ejaculated sperm.DesignEvaluation of the relative force generated by epididymal and ejaculated sperm using an 800-nm laser-generated optical trap system (titanium-sapphire, model 899-01; Coherent Innova, Palo Alto, CA).SettingUniversity-based facility at the Beckman Laser Institute and Medical Clinic and Center for Reproductive Health, University of California, Irvine.InterventionsA total of 2,720 sperm from 28 samples were randomly analyzed. Fifteen were ejaculated samples (1,650 sperm) obtained from men with proven fertilization, and 13 were epididymal samples (1,070 sperm) aspirated microsurgically from patients with obstructive azoospermia. An optical trap equipped with the 100x Neofluar objective was used to analyze an average of 100 sperm per patient.Main outcome measuresDetermination of mean relative escape force values in milliwatts for epididymal and ejaculated sperm samples.ResultsThe mean relative escape force for epididymal sperm was 32.4 mW, significantly lower than ejaculated sperm, which was 85.1 mW. By correlating epididymal sperm relative force with fertilization in vitro at an arbitrary cutoff value of 30 mW, it was found that no fertilization occurred if a sample had < 13% of sperm at that value.Conclusions[1] The average relative escape force of the epididymal sperm was found to be 60% weaker than that of ejaculated sperm. [2] It is demonstrated that the noncontact laser optical trap is a sensitive tool that can evaluate single sperm force as a new physiological parameter.

The development of the single beam gradient force optical trap has made it possible to manipulate cells solely by laser light. A continuous wave Nd:YAG (1.06 microns) laser beam was directed into a conventional microscope and focused onto the viewing plane by the objective lens. The laser beam power at which human sperm were released from the trap was measured and correlated to the sperm's linear velocity before trapping. The mean trapping power readings for slow, medium, and fast motile sperm were 57, 73, and 84 mW, respectively. The analysis of measurements over the total population demonstrated that zig-zag motile sperm had significantly higher mean power readings when compared with straight motile sperm with similar mean linear velocities. In two cases, specimens required significantly less trapping power when the measurements were repeated 24 hours later.

The force generated by the radiation pressure of a low power laser beam induces an optical trap which may be used to manipulate sperm. We studied the effect of the optical trap on sperm motility. A Nd:YAG laser beam was coupled to a conventional microscope and focused into the viewing plane by the objective lens. Sperm were caught in the trap and manipulated by a joy stick controlled motorized stage. After different exposure periods, the velocity and patterns were analysed by a computerized image processor. There were minor changes in sperm velocity when exposed to the trap for 30 seconds or less. A gradual decrease in the mean linear velocity was observed after 45 seconds of exposure. This optical micromanipulator may also be useful for studying the force generated by a single spermatozoa and evaluating the influence of drugs on motility.

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Academy of Finland Sigrid Jusélius Foundation Adipose tissue influences the physiological and pathological processes in our body by regulating lipid storage and metabolic homeostasis. Extracellular matrix (ECM) is a dynamic and complex assemblage consisting of polysaccharides, proteogylcans and signalling proteins. Though both adipocytes and non- adipose cells of the stromal fraction contribute to ECM maintenance, role of adipose tissue ECM in the disease remains poorly characterised. High fat diet (HFD) and obesity represent major risk factors for atherosclerosis. Our overall aim in this study was to understand HFD induced changes in the adipose tissue during atherosclerosis progression using single cell RNA sequencing (scRNA-seq), to identify the ligands responsible for changes in the expression of ECM components and to characterise the role of ECM protein fibrillin in disease associated tissue changes. We performed scRNA-seq in the adipose tissue of control mice and atherosclerotic LDLR-/- / ApoB100/100 subjected to 1 (early disease) or 3 months (advanced disease) of HFD. This allowed us to identify 13 different cell types in the adipose tissue of the diseased mice. Among them, we identified mesenchymal cells (MSC) undergoing changes from putatively adipogenic to fibrogenic cells. The differentially expressed genes in the MSC population exhibited functions related to ECM development, maintenance and signalling. We identified Fibrillin-1 (Fbn1) as one of the most prominent up regulated genes and studied the effect of Fbn1 knockout in ApoE-/- Fbn1C1039G+/- mice. The Fbn1 knockout mice model suited our experimental design to study the adipose tissue during atherosclerosis as the mice developed significantly large and unstable plaques characterised by large necrotic core. Our results demonstrated that adipose tissue expresses a new subtype with HFD in Fbn1 knockout mice, which could be associated with insulin resistance and fat accumulation. Fbn1 knockout led to an altered phenotype of MSCs (or adipocytes) in adipose tissue. Altogether, our analysis provides the first steps toward understanding the role of MSCs in ECM-related changes during atherosclerosis and HFD stimulation. [ABSTRACT FROM AUTHOR]