EosFP is a fluorescent protein from the coral Lobophyllia hemprichii that changes its fluorescence emission from green to red upon irradiation with near-UV light. Here we present the spectroscopic properties of wild-type EosFP and a variety of monomeric and dimeric mutants and provide a structural interpretation of its oligomerization and photoconversion, which is based on X-ray structure analysis of the green and red species that we reported recently. Because functional expression of the monomeric EosFP variant is limited to temperatures of 30 degrees C, we have developed a tandem dimer. This construct, in which two EosFP subunits are connected by a flexible 12 amino acid linker, expresses well after fusion with the androgen and endothelin A receptors at 37 degrees C. A variety of applications in cellular imaging, developmental biology and automated high-content screening applications are presented, which demonstrate that EosFP is a powerful tool for in vivo monitoring of cellular processes.

Background-Recent studies have suggested that testosterone has a protective effect in the arterial vascular system. However, little is known about the molecular aspects of the mechanism(s) involved in these processes. The aim of the present study was to investigate the effect of testosterone on neointimal plaque development and on the expression of the vascular androgen receptor. Methods and Results-Neointimal plaque formation was induced by endothelial denudation in the aortas of male New Zealand White rabbits. Aortic ring segments were cultured for 21 days after endothelial denudation. Testosterone was applied to the culture medium in different doses. Compared with the non-hormone-treated control group, a significant inhibition of neointimal plaque development (expressed as the intima/media ratio) was found at testosterone concentrations of 10 ng/mL (Pϭ0.037) and 100 ng/mL (Pϭ0.012; intima/media ratios: median of controls, 0.25; median of 10 ng/mL testosterone group, 0.15; median of 100 ng/mL testosterone group, 0.16). Associated with this inhibitory effect on plaque size was a 50% increase of the amount of androgen receptor mRNA in the arterial segments treated with testosterone. Conclusion-The beneficial effects of testosterone on postinjury plaque development underlines, at least in males, the important role of androgens in the vascular system. As our data suggest, the vascular androgen receptor is probably involved in these processes. Further studies are required to characterize the androgen receptor-dependent pathways in the vascular system. Key Words: testosterone Ⅲ receptors, androgen Ⅲ atherosclerosis T he role of androgens in atherogenesis is controversial 1 ; however, in recent years, several authors have found a number of beneficial effects of testosterone, at least in men. Animal studies have documented an inhibitory effect on plaque development in the cholesterol-fed rabbit model, 2,3 whereas in recent clinical investigations, acute hemodynamic effects of testosterone on coronary vasomotion and stress-test induced ischemia were observed. 4,5 Thus far, only limited information is available regarding the possible involvement of arterial androgen receptors in these processes. Thus, the aim of the present study was to investigate, in an experimental model, (1) the dose-dependent effects of testosterone on plaque development, (2) the expression of the androgen receptor in arteries, and (3) possible dose-dependent changes of androgen receptor expression induced by testosterone. Methods Organ Culture SystemTwelve-week-old male New Zealand White rabbits were used for the present study. The rabbits received standard chow without cholesterol (Altromin Inc) and were housed individually (no female rabbits were present). After sacrifice, the abdomen was opened under sterile conditions, and the connective tissue was removed from the aorta. A 3F-Fogarty catheter (Baxter Inc) was inserted below the iliac bifurcation, and endothelial denudation was performed once with the inflated catheter. The aorta was then comp...

This paper describes the macroflora and macrofauna associated with two bull kelp species, Laminaria hyperborea and L. digitata, at the island of Helgoland, North Sea. During a study period of seven months (March-September 1987), 29 macroflora species and 125 macrofauna species were found. The dominant taxonomic groups were Polychaeta (25 species), Bryozoa (17), Amphipoda (14), Hydrozoa (10) and Ascidiae (8). The species maximum was in July. In general, L.hyperborea was preferred as a substrate for settlement to L. digitata. Compositio n of the communities associated with kelp changed.during the season accordim:j to exposure to wave action, and according to location on the kelp thallus. The rhizoid community of both kelps bore more species at exposed locations. Wave-exposed L. digitata lacked obvious faunal settlement on both phylloid and cauloid. Phylloid and cauloid of L. hyperborea were chosen as an attractive substrate at both sheltered and wave-exposed locations, showing an association of encrusting bryozoan and hydrozoan colonies.

Chronic inflammation increases the risk of cancer and many cancers, including prostate cancer, arise at sites of chronic inflammation. Inducible nitric oxide synthase (iNOS) is an enzyme dominantly expressed during inflammatory reactions. Although synthesis of high amounts of nitric oxide (NO) by iNOS has been demonstrated in pathophysiological processes, such as acute or chronic inflammation, autoimmune diseases or tumorigenesis, the role of iNOS activity in most of these diseases is poorly understood. Analysing prostate cancer biopsies by immunohistochemistry we found iNOS protein expression in tumor cells strongly paralleled by nitrotyrosine suggesting that iNOS is fully active. In vitro, NO inhibits androgen receptor-dependent promoter activity and prostate specific antigen production as well as DNAbinding activity of the androgen receptor (AR) in a concentration-dependent manner. Inhibition of the activity of androgen receptor-dependent reporter constructs is neither owing to diminished AR protein levels nor owing to an inhibition of its nuclear import. In addition, NO inhibits the proliferation of androgen receptor-positive prostate cancer cells significantly more efficiently than proliferation of androgen receptor-negative prostate cancer cells. In summary, our findings suggest that intratumoral iNOS activity favors development of prostate cancer cells that are able to proliferate androgen receptor-independently, thereby promoting prostate tumor progression.

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