Plantar zygodactylous triradii and corresponding patterns

Taking into consideration the methods of Cummins and Sicomo ('23), Cummins and Midlo ('43) and Penrose and Loesch ('69) a new classification scheme of plantar zygodactylous triradii has been introduced, differentiating three expression types, i.e., strong, medium and weak. On the basis of plantar prints of 500 ♂ Viennese the frequencies of these expression types were established. Furthermore their relations to the pattern types located proximally were studied. It resulted that certain pattern types are always and others never associated with a zygodactylous triradius. Therefore it is possible to predict the existence of a zygodactylous triradius non visible on the print if the corresponding pattern type is known.     

Phospholipid transfer protein interacts with and stabilizes ATP-binding cassette transporter A1 and enhances cholesterol efflux from cells

Phospholipid lipid transfer protein (PLTP) is ubiquitously expressed in animal tissues and plays multiple roles in lipoprotein metabolism, but the function of peripheral PLTP is still poorly understood. Here we show that one of its possible functions is to transport cholesterol and phospholipids from cells to lipoprotein particles by a process involving PLTP interactions with cellular ATP-binding cassette transporter A1 (ABCA1). When ABCA1 was induced in murine macrophages or ABCA1-transfected baby hamster kidney cells, PLTP gained the ability to promote cholesterol and phospholipid efflux from cells. Although PLTP alone had lipid efflux activity, its maximum activity was observed in the presence of high density lipoprotein particles. Pulsechase studies showed that the interaction of PLTP with ABCA1-expressing cells played a role in promoting lipid efflux. Overexpression of ABCA1 dramatically increased binding of both PLTP and apoA-I to common sites on the cell surface. Both PLTP and apoA-I were covalently cross-linked to ABCA1, each protein blocked cross-linking of the other, and both PLTP and apoA-I stabilized ABCA1 protein. These results are consistent with PLTP and apoA-I binding to ABCA1 at the same or closely related sites. Thus, PLTP mimics apolipoproteins in removing cellular lipids by the ABCA1 pathway, except that PLTP acts more as an intermediary in the transfer of cellular lipids to lipoprotein particles.     

Competition of spontaneous protein folding and mitochondrial import causes dual subcellular location of major adenylate kinase

Sorting of cytoplasmically synthesized proteins to their target compartments usually is highly efficient so that cytoplasmic precursor pools are negligible and a particular gene product occurs at one subcellular location only. Yeast major adenylate kinase (Adk1p/Aky2p) is one prominent exception to this rule. In contrast to most mitochondrial proteins, only a minor fraction (6-8%) is taken up into the mitochondrial intermembrane space, whereas the bulk of the protein remains in the cytosol in sequence-identical form. We demonstrate that Adk1p/Aky2p uses a novel mechanism for subcellular partitioning between cytoplasm and mitochondria, which is based on competition between spontaneous protein folding and mitochondrial targeting and import. Folding is spontaneous and rapid and can dispense with molecular chaperons. After denaturation, enzymatic activity of Adk1p/Aky2p returns within a few minutes and, once folded, the protein is thermally and proteolytically very stable. In an uncoupled cell-free organellar import system, uptake of Adk1p/Aky2p is negligible, but can be improved by previous chaotropic denaturation. Import ensues independently of Hsp70 or membrane potential. Thus, nascent Adk1p/Aky2p has two options: either it is synthesized to completion and folds into an enzymatically active import-incompetent conformation that remains in the cytosol; or, during synthesis and before commencement of significant tertiary structure formation, it reaches a mitochondrial surface receptor and is internalized.     

Behavioral experiments on the visual processing of color stimuli inPieris brassicae L. (Lepidoptera)

Summary In spontaneous-choice experiments on the butterflyPieris brassicae L. (Pieridae), spectral-effectiveness and spectral-sensitivity functions were obtained for various behaviors.Pilot experiments with colored PVC films, for which the relative number of reflected quanta with regard to the given illumination had been calculated, showed that the feeding response is distinctly intensity-dependent (Fig. 4). The animals are also capable of color discrimination independent of this intensity discrimination;P. brassicae prefers blue to other colors (e.g., orange, red and purple) with higher relative quantum numbers (Fig. 3) and distinguishes golden yellow and red from gray shades as well as from black and white (Fig. 5a, b).The results of subsequent spontaneous-choice experiments, using as stimuli monochromatic lights with known quantum flux, indicate that the various visually controlled functional categories of behavior can be assigned to the following spectral regions (Figs. 6, 8): 1. The open-space reaction corresponds to the UV and violet region, ca. 320–420 nm; 2. The feeding reaction corresponds to the blue region, ca. 420–500 nm, and the orange-red region, ca. 590–610 nm; 3. Egg-laying and drumming correspond to the green-yellow region, ca. 520–580 or 590 nm, respectively. The intensity dependence of the individual responses is again apparent in these experiments with monochromatic light stimuli (Figs. 7, 11, 12a).Even at very high intensities and when the content of the relevant wavelength is high, white light is practically ineffective for the feeding reaction (Fig. 9), drumming and egg-laying (cf. Results), regardless of its UV content. The open-space reaction, however, can be elicited by white light according to its UV content (Fig. 12 b).P. brassicae cannot be trained to give a feeding response to monochromatic light stimuli (Fig. 10).Experiments with mixtures of wavelengths have shown that the combination of the two maxima in the spectral sensitivity curve for the feeding reaction (=600 plus 447 nm) is just as effective as =447 nm alone (Fig. 13, left). Moreover, the mixture producing the hypothetical Pieris purple (=600 plus 370 nm) is no more or less effective in eliciting the feeding and open-space reactions than the more effective component for each of these reactions when presented alone (Fig. 13, right). With the mixture of =600 plus 558 nm, both the feeding reaction and drumming are distinctly reduced (Fig. 13, middle). This mixed color, unlike the other two mixtures tested, has a color quality different from that of the component colors.That the behavior ofP. brassicae is exclusively wavelength-specific can thus be ruled out. There are indications that wavelength-specific behavior and color vision are both present.Abbreviation RNQ relative number of quanta This publication is dedicated to Professor Dr. Dr.h.c. H. Autrum on the occasion of his 80th birthday     

Light-dependent dynamics of gap junctions between horizontal cells in the retina of the crucian carp

Summary The dynamics of gap junctions between outer horizontal cells or their axon terminals in the retina of the crucian carp were investigated during light and dark adaptation by use of ultrathin-section and freeze-fracture electron microscopy. Light adaptation was induced by red light, while dark adaptation took place under ambient dark conditions. The two principal findings were: (1) The density of connexons within an observed gap junction is high in dark-adapted retina, and low in light-adapted retina. This, respectively, may reflect the coupled and uncoupled state of the gap junction. (2) The size of individual gap junctions is larger in light-than in dark-adapted retinae. Whereas the overall area occupied by gap junctions is reduced with dark adaptation, the percentage of small and very small gap junctions increases dramatically. A lateral shift of connexons in the gap junctional membrane is strongly suggested by these reversible processes of densification and dispersion. Two additional possibilities of gap junction modulation are discussed: (1) the de novo formation of very small gap junctions outside the large ones in the first few minutes of dark adaptation, and (2) the rearrangement of a portion of the very large gap junctions. The idea that the cytoskeleton is involved in such modulatory processes is corroborated by thin-section observations.Dedicated to Professor J. Peiffer on the occasion of his 65th birthday     

C4 allotyping distinguishes HLA-1314.1 and B14.2 subgroups

Complement allotyping (C4, C2, and BF) was performed in 60 unrelated individuals and 15 families characterized for the subtypes (14.1 and 14.2) within HLA-B14. Eighty-seven percent of B14.2 individuals typed positive for the rare C4A2 variant. In contrast, less than 7% of B14.1 individuals were positive for this C4 allotype which is in keeping with a control background frequency. Family studies revealed that three distinct complotypes (complement haplotypes) are characteristic for the two HLA-1314 subgroups. The SC22 and FC31 complotypes characterize the B14.2 subtype, whereas SC31 appears to define B14.1.     

Biosynthesis of vitamin B12: Timing of the methylation steps between uro'gen III and cobyrinic acid

The sequence of methylation between uro'gen III and cobyrinic acid has been defined by applying ¹³C pulse-labeling methods to a cell-free system from Propionibacterium shermanii. Feeding experiments using unenriched S-adenosyl methionine (¹²CH₃-SAM) followed by ¹³C-enriched SAM (¹³CH₃-SAM) (or vice versa) at various intervals caused differentiation in the ¹³C NMR signals of the SAM-derived methyl groups in cobyrinic acid (isolated as cobester). Unenriched uro'gen III and sirohydrochlorin as substrates led to cobyrinic acid containing seven and five enriched methyl groups, respectively, which on NMR analysis gave as a sequence of methylation C-2 > C-7 > C-20 > C-17 > C-12α > C-1 > C-5 C-15.     

Life in hot springs and hydrothermal vents

Hot springs and hydrothermal systems occurring within volcanic areas are inhabited by hyperthermophilic microorganisms, some of which grow at temperatures up to 110 °C. Hyperthermophiles grow anaerobically or aerobically by diverse metabolic types. Within the high temperature ecocystems, primary production is independent from solar energy.Presented at the Session Water in the Solar System and Its Role in Exobiology during the 26th General Assembly of the European Geophysical Society, 22–26 april 1991 in Wiesbaden, Germany.