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The yellow‐flowered monkshood Aconitum lycoctonum has variable degrees of inbreeding among populations, despite being primarily bee‐pollinated. Here we examined the pollination ecology of A. lycoctonum. We investigated pollinator community and frequency in four populations at two altitudes over two years. We found that flowers were more often visited at low elevation than at high elevation. However, because flowers lived longer at high elevation than at low elevation, and plants at high elevation had more flowers than at low elevation, the overall chance of a plant being visited may be greater at high elevation. Breeding system experiments showed that at least some populations of A. lycoctonum were self‐compatible and also were not completely protandrous. Thus selfing, especially by geitonogamous pollen, will be common if pollinators often visit several flowers within a plant, as we found to be true for the main pollinator (bumblebees) of A. lycoctonum. Although the stereotypical behavior of bees is to move upwards, 17% of the within‐plant movements of the main pollinator (Bombus gerstaeckeri) were downwards, i.e. from a male‐phased to a female‐phased flower because the flowers open from the bottom to the top of the plant. Other pollinators of A. lycoctonum moved less often within plants. We conclude that in addition to differences in self‐compatibility, differences in pollinator abundance and behavior could have led to variation in the realized mating system in different A. lycoctonum populations.

Crucifers (Brassicaceae) in 11 genera are often infected by rust fungi in the Puccinia monoica complex. Infection causes a 'pseudoflower' to form that is important for attracting insect visitors that sexually outcross the fungus. 'Pollinator' attraction is accomplished through visual floral mimicry, the presence of a nectar reward and floral fragrances. Here we used gas chromatography and mass spectrometry to identify and quantify fragrance production by these rust fungi on several Arabis hosts, and by co-occurring true flowers that share insect visitors. Fungal pseudoflowers produced distinctive floral fragrances composed primarily of aromatic alcohols, aldehydes and esters. Pseudoflower fragrances were chemically similar to noctuid-moth-pollinated flowers, such as Cestrum nocturnum and Abelia grandiflora, but were very different from host flowers, host vegetation and the flowers of coblooming, nonhost angiosperms. There was variation in the quantity and composition of fragrance profiles from different fungal species as well as within and among hosts. The evolution of scent chemistry is relatively conservative in these fungi and can be most parsimoniously explained in three steps by combining chemical data with a previously determined rDNA ITS sequence-based phylogeny. Pseudoflower scent does not appear to represent a simple modification of host floral or vegetative emissions, nor does it mimic the scent of coblooming flowers. Instead, we suspect that the unique fragrances, beyond their function as pollinator attractants, may be important in reducing gamete loss by reinforcing constancy among foraging insects.

Objective. The membrane-anchored metalloproteinase disintegrin ADAM15 is up-regulated in osteoarthritis and has been implicated in proteolysis and cell-matrix interactions. To address its role in cartilage metabolism, we performed an analysis of joint morphology in aging mice with a targeted inactivation of the ADAM15 gene (ADAM15 ؊/؊). In addition, a human chondrocyte cell line overexpressing ADAM15 was used to investigate the role of ADAM15 in an in vitro model of chondrocyte-matrix interactions.Methods. Knee joint sections from 3-, 6-, and 12-14-month-old ADAM15 ؊/؊ and wild-type (WT) 129/ SvJ mice were examined for synovial hyperplasia, cartilage degradation, and osteophyte formation. Stable transfection of the human T/C28a4 chondrocyte cell line with full-length human ADAM15 complementary DNA led to the establishment of ADAM15-overexpressing chondrocytes that were further analyzed for their capability to adhere to and to survive on cartilage matrix molecules (fibronectin and types II and VI collagen) under conditions of serum starvation. ADAM15 expression was investigated by reverse transcriptionpolymerase chain reaction and Western blotting. Results. Aging ADAM15؊/؊ mice exhibited accelerated development of osteoarthritic lesions compared with WT mice, and the difference was statistically significant at age 12 months. The osteoarthritic changes preferentially affected male ADAM15 ؊/؊ mice. ADAM15 overexpression in T/C28a4 cells led to the specific reinforcement of chondrocyte adhesion to cartilage types II and VI collagen, and this was associated with enhanced cell viability under conditions of serum starvation.Conclusion. The accelerated development of murine osteoarthritis in ADAM15 deficiency as well as the proadhesive and cell survival-promoting in vitro effect of ADAM15 overexpression suggest a homeostatic rather than a destructive role of ADAM15 in cartilage remodeling.ADAM15 belongs to a family of adamalysin (ADAM) metalloproteinase disintegrins (MDCs) that are membrane-anchored glycoproteins containing modular metalloproteinase, disintegrin, cysteine-rich, and epidermal growth factor-like domains, followed in most cases by a transmembrane region and a cytoplasmic tail (1). ADAMs have been implicated in fertilization, myogenesis, neurogenesis, and protein ectodomain shedding (for recent reviews, see refs. 1 and 2) and are also thought to play roles in cell-cell or cell-matrix adhesion through interactions with integrins (3,4) or syndecans (5,6).For ADAM15, a variety of potential functions have been postulated. Thus, cell-cell interaction studies using its recombinant extracellular domains provide experimental evidence for a role in integrin ligation (␣v␤3, ␣5␤1, ␣9␤1) (3,7,8). The localization to adherens junctions in endothelial cell cultures and an enhancement of cell-cell interactions in ADAM15-overexpressing fibroblasts (9) indicate a role in cell adhesion. In addition, ADAM15 contains a catalytic site consensus sequence for zinc-dependent metalloprotein-