Male inbreeding status affects female fitness in a seed-feeding beetle.

Inbreeding generally reduces male mating activity such that inbred males are less successful in male-male competition. Inbred males can also have smaller accessory glands, transfer less sperm and produce sperm that are less motile, less viable or have a greater frequency of abnormalities, all of which can reduce the fertilization success and fitness of inbred males relative to outbred males. However, few studies have examined how male inbreeding status affects the fitness of females with whom they mate. In this study, we examine the effect of male inbreeding status (inbreeding coefficient f = 0.25 vs. f = 0) on the fecundity, adult longevity and the fate of eggs produced by outbred females in the seed-feeding beetle, Callosobruchus maculatus. Females mated to inbred males were less likely to lay eggs. Of those that laid eggs, females mated to inbred males laid 6-12% fewer eggs. Females mated to inbred males lived on average 5.4% longer than did females mated to outbred males, but this effect disappeared when lifetime fecundity was used as a covariate in the analysis. There was no effect of male inbreeding status on the proportion of a female's eggs that developed or hatched, and no evidence that inbred males produced smaller nuptial gifts. However, ejaculates of inbred males contained 17-33% fewer sperm, on average, than did ejaculates of outbred males. Our study demonstrates that mating with inbred males has significant direct consequences for the fitness of female C. maculatus, likely mediated by effects of inbreeding status on the number of sperm in male ejaculates. Direct effects of male inbreeding status on female fitness should be more widely considered in theoretical models and empirical studies of mate choice.

IL-6 and its soluble receptor augment aggrecanase-mediated proteoglycan catabolism in articular cartilage.

Elevated concentrations of interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) in the synovial fluids and serum of patients with arthritis have been implicated in the joint tissue destruction associated with these conditions, however studies conducted to date on the role and effects of IL-6 in the process of cartilage proteoglycan (aggrecan) catabolism are disparate. In the present study, bovine articular cartilage explants were maintained in a model organ culture system in the presence or absence of IL-1alpha or TNF-alpha, and under co-stimulation with or without IL-6 and/or sIL-6R. After measuring proteoglycan loss from the explants, the proteolytic activity and expression profiles of aggrecanase(s) was assessed for each culture condition. Stimulation of cartilage explants with IL-6 and/or sIL-6R potentiated aggrecan catabolism and release above that seen in the presence of IL-1alpha or TNF-alpha alone. This catabolism was associated with aggrecanase (but not MMP) activity, with correlative mRNA expression for aggrecanase-2.

n-3 fatty acids specifically modulate catabolic factors involved in articular cartilage degradation.

This study describes specific molecular mechanisms by which supplementation with n-3 fatty acids (i.e. those present in fish oils) can modulate the expression and activity of degradative and inflammatory factors that cause cartilage destruction during arthritis. Our data show that incorporation of n-3 fatty acids (but not other polyunsaturated or saturated fatty acids) into articular cartilage chondrocyte membranes results in a dose-dependent reduction in: (i) the expression and activity of proteoglycan degrading enzymes (aggrecanases) and (ii) the expression of inflammation-inducible cytokines (interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha) and cyclooxygenase (COX-2), but not the constitutively expressed cyclooxygenase COX-1. These findings provide evidence that n-3 fatty acid supplementation can specifically affect regulatory mechanisms involved in chondrocyte gene transcription and thus further advocate a beneficial role for dietary fish oil supplementation in alleviation of several of the physiological parameters that cause and propogate arthritic disease.

Fabrication of conducting polymer interconnects.

A nonmechanical approach to the construction of complex three-dimensional interconnect arrays has been developed with the use of conducting polymer dendrites. Electrically independent connections between pairs of wires in an array were successfully grown through alternating-current electrochemical polymerization of poly(3-methylthiophene), without mechanical or optical masking steps. The electrically active links were insulated by subsequent electropolymerization of 4-vinylpyridine or 2-methylthiophene or by the dip-coating of the connections in a polystyrene solution.

Developmental levels of social cognition in head-injury patients.

Ten adults, who had sustained a closed head injury, were interviewed regarding their self-understanding, concepts of persons, and interpersonal negotiation strategies. Responses were evaluated in terms of developmental levels of social cognition. Levels of interpersonal negotiation strategies were significantly lower than levels of self-understanding, descriptions of psychological characteristics of self were at a significantly higher level than descriptions of active and physical characteristics of self. Within interpersonal conflict situations, proposed solutions were at a significantly lower level than the justifications offered for the solutions. In general, developmental levels of social cognition were comparable to levels exhibited by non-clinical samples of adolescents. The two areas in which the head-injury patients appeared to perform at a significantly higher level than adolescents were their justifications for their proposed solutions to the interpersonal conflict situations and their ability to express the emotional consequences of interpersonal conflict.

Luminescent colloidal silicon suspensions from porous silicon.

A procedure for generating colloidal suspensions of Si that exhibit luminescence, attributed to quantum confinement effects, is described. Samples of n- or p-type Si that have been electrochemically etched to form porous Si can be ultrasonically dispersed into methylene chloride, acetonitrile, methanol, toluene, or water solvents, forming a suspension of fine Si particles that luminesce. Transmission electron microscopy analyses show that the Si particles have irregular shapes, with diameters ranging from many micrometers to nanometers. Luminescent, composite polystyrene/Si films can be made by the addition of polystyrene to a toluene suspension of the Si nanoparticles and casting of the resulting solution onto a glass slide.