The epiphytic lichen zones in rural Denmark and Schleswig–Holstein

The epiphytic lichen flora of 332 trees standing at roadsides or in churchyards in non–urban areas of Denmark and Schleswig–Holstein, Federal Republic of Germany, was investigated. The condition of the lichen vegetation in each of 107 subareas was evaluated by means of a nine–point scale largely based upon presence, fertility and vitality of Anaptychia ciliaris and Physconia pulverulacea.
A marked depauperation of the lichen communities of the alliance Xanthorion parietinae is demonstrated in Schleswig–Holstein and is attributed to long–range SO₂ air pollution. No significant pattern of adverse effects on the corresponding communities can be seen in Danish rural areas, but the reduction in frequency and size of Ramalina species in recent times is believed to be the result of background air pollution.
A list of 111 recorded taxa is given and selected species are commented on. Candelariella reflexa (Nyl.) Lettau is reported as new to Denmark. The effects of agricultural spraying and the decrease in the numbers of phorophytes in recent decades are discussed.     

Green light for the secretory pathway

Summary Since the advent of green-fluorescent protein (GFP) technology there has been an explosion of interest in applying this molecule to cell biology. This review summarizes new insights in secretory membrane traffic obtained by the use of GFP fusion proteins. Transport steps between the endoplasmic reticulum and the Golgi apparatus, intra-Golgi traffic, and transport from the Golgi to the plasma membrane are discussed. In addition, insights into the dynamics of the Golgi compartment in plant cells and in mitotic mammalian cells have been included. We conclude that membrane traffic in the secretory pathway appears to be much more dynamic and diverse than previously thought and that GFP promises to be a powerful means to unravel these complex processes.     

Differences in apolipoprotein(a) polymorphism in West Greenland Eskimos and Caucasian Danes

Summary Previous studies in Greenland suggest that death rates from ischemic heart disease [IHD] are lower in Eskimos than in Danes and other Caucasian populations. This has been explained by a high intake of n-3 polyunsaturated fatty acids with beneficial effects on blood lipids and hemostasis. In other populations, lipoprotein(a) [Lp(a)] is associated with IHD, plasma concentrations of Lp(a) being genetically determined to a major extent. We have compared Lp(a) concentrations and apo(a) phenotypes in 120 Greenlandic Eskimos with those in 466 Danish men. The median Lp(a) concentration in Eskimos (8.7mg/dl;[95% CI 6.5–10.7]) was not significantly different from that in Danes (6.3mg/dl; [95% CI 5.2–7.0]), whereas the 90th percentile was significantly higher among Danes: 46.36mg/dl; [95% Cl 43.0–54.3] vs. 27.6mg/dl [95% CI 20.7–36.9]. In 20% of the Danes, but in only 8% of the Eskimos (P = 0.009), the concentration of Lp(a) exceeded 30mg/dl. The difference is probably explained by a low frequency of the low molecular weight apo(a) phenotypes among Eskimos, since the apo(a) isoforms F and B were absent, and the S1 and S2 types were present in only 3.3% of Eskimos. In contrast, these apo(a) isoforms were present in 26.6% of the Danes in either single-band or double-band phenotypes. The pattern of apo(a) polymorphism found in this study could provide part of a genetic explanation for the putative low rates of IHD in Eskimo populations.     

The rifampicin-inducible genes srn6 from F and pnd from R483 are regulated by antisense RNAs and mediate plasmid maintenance by kiiling of plasmid-free segregants

The gene systems srnB of plasmid F and pnd of plasmid R483 were discovered because of their induction by rifampicin. Induction caused membrane damage, RNase I influx, degradation of stable RNA and, consequently, cell killing. We show here that the srnB and pnd systems mediate efficient stabilization of a mini-R1 test-plasmid. We also show that the killer genes srnB' and pndA are regulated by antisense RNAs, and that the srnC- and pndB-encoded antisense RNAs, denoted SrnC- and PndB-RNAs, are unstable molecules of approximately 60 nucleotides. The srnB and pndA mRNAs were found to be very stable. The differential decay rates of the inhibitory antisense RNAs and the killer-gene-encoding mRNAs explain the induction of these gene systems by rifampicin. Furthermore, the observed plasmid-stabilization phenotype associated with the srnB and pnd systems is a consequence of this differential RNA decay: the newborn plasmid-free cells inherit the stable mRNAs, which, after decay of the unstable antisense RNAs, are translated into killer proteins, thus leading to selective killing of the plasmid-free segregants. Thus our observations lead us to conclude that the F srnB and R483 pnd systems are phenotypically indistinguishable from the R1 hok/sok system, despite a 50% dissimilarity at the level of DNA sequence.     

Chemosyndromes in the lichen genus Teloschistes (Teloschistaceae, Lecanorales)

The secondary metabolites of 150 specimens belonging to 29 species of Teloschistes were analysed with HPLC. Seven anthraquinones were detected of which parietin dominated with minor proportions of emodin, teloschistin, fallacinal and parietinic acid. The depsidones vicanicin, caloploicin, and isofulgidin occurred together with some compounds of unknown identity in varying proportions in T. flavicans, T. peruensis, T. stellatus, and one unnamed taxon. Nine chemosyndromes were found in the genus. Most species had only one chemosyndrome, but T. flavicans s. lat. had six syndromes. The geographical distribution patterns of these chemosyndromes in T. flavicans are discussed as well as the applicability of chemical characters for species delimitation in Teloschistes.