Sexual expression and cognitive function: gender-divergent associations in older adults

Prior research demonstrates a positive association between sexual activity and cognitive function in later life. However, the relationship between the type of sexual activity and cognitive function in older adulthood remains unclear. This study explores the associations between the frequency of engaging in different types of sexual activities (intercourse, masturbation, and kissing/petting/fondling) and cognitive function in older women and men. Using data from Wave 6 of the English Longitudinal Study of Ageing (ELSA), 1915 women and 2195 men (age range 50-89 years; n = 4110) reporting any type of sexual activity over the past 12 months, were included in the study. Multiple regression controlling for age, education, satisfaction with sex life, cohabiting, wealth, general health, physical activity, depression and loneliness, was used to explore the associations between the frequency of engagement in intercourse, masturbation and kissing/petting/fondling, and two measures of cognitive function; word recall and number sequencing. For women, masturbation was linked to better word recall (p = .008), whilst for men, kissing/petting/fondling was associated with better number sequencing (p = .035). In women (p = .016) and men (p = .018), dissatisfaction with sex life was associated with better number sequencing. The results point to gendered links between sexual activity and cognitive function. These gender-related divergences may reflect differences in biological/neurological mechanisms, or in cognitive lifestyle factors that could influence cognitive reserve in later life. This novel study underscores the need to delineate the underlying mechanisms of the association between sex and cognition in men and women

Polymorphism in the lipase genes of Geotrichum candidum strains

The fungus Geotrichum candidum produces extracellular lipases. Purification and characterization of different lipase isoforms from various G. candidum strains is difficult due to the close physical and biochemical properties of the isoforms. Consequently, the characterization of these enzymes and their substrate specificites has been difficult. We have determined the lipase genes present in four strains of G. candidum (ATCC 34614, NRCC 205002, NRRL Y-552 and NRRL Y-553) by molecular cloning and DNA sequencing. Each strain contains two genes similar to the previously identified lipase I and lipase II cDNAs. Our data suggest that no other related lipase genes are present in these strains. Each lipase-gene family shows sequence variation (polymorphism) that is confirmed by Southern-blot analysis. This polymorphism and the sequence differences between lipase I and lipase II have been localized within the previously determined three-dimensional structure of lipase II. Although most of the amino acid substitutions are located on the protein surface, some are present in structural features possibly involved in determining substrate specificity.NRC publication: Ye

Cuticular permeance in relation to wax and cutin development along the growing barley ( Hordeum vulgare ) leaf.

The developing leaf three of barley provides an excellent model system for the direct determination of relationships between amounts of waxes and cutin and cuticular permeance. Permeance of the cuticle was assessed via the time-course of uptake of either toluidine blue or 14C-labelled benzoic acid ([14C] BA) along the length of the developing leaf. Toluidine blue uptake only occurred within the region 0–25 mm from the point of leaf insertion (POLI). Resistance—the inverse of permeance—to uptake of [14C] BA was determined for four leaf regions and was lowest in the region 10–20 mm above POLI. At 20–30 and 50–60 mm above POLI, it increased by factors of 6 and a further 32, respectively. Above the point of emergence of leaf three from the sheath of leaf two, which was 76–80 mm above POLI, resistance was as high as at 50–60 mm above POLI. GC-FID/MS analyses of wax and cutin showed that: (1) the initial seven fold increase in cuticular resistance coincided with increase in cutin coverage and appearance of waxes; (2) the second, larger and final increase in cuticle resistance was accompanied by an increase in wax coverage, whereas cutin coverage remained unchanged; (3) cutin deposition in barley leaf epidermis occurred in parallel with cell elongation, whereas deposition of significant amounts of wax commenced as cells ceased to elongate