Light-induced linear dichroism in photoreversibly photochromic sensor pigments. – VI. Relation between the two pigments of the mycochrome system in Alternaria cichorii

Conidiation in Alternaria cichorii Nattras is reversibly stimulated by near ultraviolet radiation (NUV, ca 313 nm) and inhibited by blue light (ca 450 nm) and seems to be a mycochrome-mediated process. After induction with plane-polarized NUV, blue light polarized perpendicularly to the NUV was more effective in counteracting the induction than was blue light polarized parallel to the NUV. From this the conclusions are drawn that (a) both the blue-absorbing component (presumably a flavo-protein) and the P_NUV of the mycochrome system are membrane-bound and that (b) the transition moment associated with blue light absorption in the presumed flavoprotein forms an angle of at least 53° with the transition moment associated with NUV absorption in P_NUV.     

IL-33 Induces IL-9 Production in Human CD4+ T Cells and Basophils

IL-33, an IL-1 family member and ligand for the IL-1 receptor-related protein ST2, has been associated with induction of Th2 cytokines such as IL-4, IL-5, and IL-13. Here, we report that IL-33 can initiate IL-9 protein secretion in vitro in human CD4+ T cells and basophils isolated from peripheral blood. TGF-β has been described as a critical factor for IL-9 induction in Th2 cells; however, we found that TGF-β also induces co-production of IL-9 in purified, naïve (>99%) CD4⁺CD45RA⁺CD45RO⁻CD25⁻ T cells differentiated towards a Th1 profile. Subsequently, it was demonstrated that TGF-β is important, although not an absolute requirement, for IL-9 production in CD4+ T cells. IL-9 production by purified (>95%) human basophils, cultured for 24 h with IL-3 or IL-33, was found, with a strong synergy between the two, likely to be explained by the IL-3 upregulated ST2 expression. Collectively, these data indicate that barrier functioning cells are important for the regulation of IL-9 production by immune cells in inflamed tissue.     

Breeding latitude leads to different temporal but not spatial organization of the annual cycle in a long‐distance migrant

The temporal and spatial organization of the annual cycle according to local conditions is of crucial importance for individuals’ fitness. Moreover, which sites and when particular sites are used can have profound consequences especially for migratory animals, because the two factors shape interactions within and between populations, as well as between animal and the environment. Here, we compare spatial and temporal patterns of two latitudinally separated breeding populations of a trans‐Equatorial passerine migrant, the collared flycatcher Ficedula albicollis, throughout the annual cycle. We found that migration routes and non‐breeding residency areas of the two populations largely overlapped. Due to climatic constraints, however, the onset of breeding in the northern population was approximately two weeks later than that of the southern population. We demonstrate that this temporal offset between the populations carries‐over from breeding to the entire annual cycle. The northern population was consistently later in timing of all subsequent annual events – autumn migration, non‐breeding residence period, spring migration and the following breeding. Such year‐round spatiotemporal patterns suggest that annual schedules are endogenously controlled with breeding latitude as the decisive element pre‐determining the timing of annual events in our study populations.     

Antifouling activity of synthesized peptide analogs of the sponge metabolite barettin

Barettin (cyclo [(6-bromo-8-en-tryptophan) arginine]), a diketopiperazine isolated from the marine sponge Geodia barretti, is a potent inhibitor of barnacle larvae settlement with an EC50-value of 0.9 microM. In the present study, 14 analogs of barettin and its structural congener dipodazine were synthezised and tested for their ability to inhibit larval settlement. Two of the analogs have an intact barettin skeleton. The remaining analogs have a dipodazine skeleton (a diketopiperazine where arginine is replaced with glycine). Six of the tested synthetic analogs displayed significant settlement inhibition with the most potent inhibitor being benzo[g]dipodazine, which displayed even stronger activity than barettin (EC50-value 0.034 microM). The effect of benzo[g]dipodazine was also shown to be readily reversible, when cyprids were transferred to filtered seawater (FSW).     

Selective assay of monomeric and filamentous actin in cell extracts,using inhibition of deoxyribonuclease I

A simple and selective assay for monomeric and filamentous actin is presented, based on the inhibition of DNAase I by actin. In mixtures of monomeric and filamentous actin, only the monomeric form is measured as DNAase inhibitor. The total amount of actin in a sample can be determined after depolymerization of F actin with guanidine hydrochloride. The assay is rapid enough to detect changes in the polymerization state of actin in vitro over time intervals as short as 3 min. Data characterizing unpolymerized and filamentous actin pools in extracts of human platelets, lymphocytes and HeLa cells are presented.     

Synthesis of mannose oligosaccharides via reversal of the α-mannosidase reaction

Summary Three naturally occurring isomers of the disaccharideO--d-mannosyl-d-mannoside were synthesized by reversing the hydrolytic activity of jack bean -mannosidase at 75°C in a very high concentration of mannose. Higher oligosaccharides were also obtained at the later stages of the reaction. The maximum total yield of disaccharides was 37% (w/w) based on the total amount of saccharides.     

Using Satellite Remote Sensing to Estimate the Colored Dissolved Organic Matter Absorption Coefficient in Lakes

Given the importance of colored dissolved organic matter (CDOM) for the structure and function of lake ecosystems, a method that could estimate the amount of CDOM in lake waters over large geographic areas would be highly desirable. Satellite remote sensing has the potential to resolve this problem. We carried out model simulations to evaluate the suitability of different satellite sensors (Landsat, IKONOS, and the Advanced land Imager [ALI]) to map the amount of CDOM in concentration ranges that occur in boreal lakes of the Nordic countries. The results showed that the 8-bit radiometric resolution of Landsat 7 is not adequate when absorption by CDOM at 420 nm is higher than 3 m⁻¹. On the other hand, the 16-bit radiometric resolution of ALI, a prototype of the next generation of Landsat, is suitable for mapping CDOM in a wider range of concentrations. An ALI image of southern Finland was acquired on 14, July 2002 and in situ measurements were carried out in 15 lakes (18 stations). The results showed that there is a high correlation (R² = 0.84) between the 565 nm/660 nm ALI band ratio and the CDOM absorption coefficient in lakes. Analysis of 245 lakes in the acquired satellite image showed a normal distribution of CDOM concentration among the lakes. However, the size distribution of lakes was highly skewed toward small lakes, resulting in the CDOM concentration per unit lake area being skewed toward high values. We showed that remote sensing enables synoptic monitoring of the CDOM concentration in a large number of lakes and thus enables scaling up to the level of large ecosystems and biomes.