Modulation of beta-oxidation and proton conductance pathway of brown adipose tissue in hypo- and hyperinsulinemic states

The metabolic capacity of interscapular brown adipose tissue of hypoinsulinemic (diabetic) rats is decreased and a reduced beta-oxidative capacity contributes to this metabolic alteration. It was thus of interest to compare, in diabetic and in chronically (8 days) insulin-infused rats, the beta-oxidative capacity and indices of the thermogenic state (GDP-binding and 32 000 Mr protein) in this tissue. Mitochondrial GDP-binding and 32 000 Mr protein were both decreased in diabetic rats compared to appropriate controls and markedly increased as was also the beta-oxidative capacity in hyperinsulinemic rats.     

Ultrastructural immunocytochemical evidence for peptidergic neurotransmission in the pond snail Lymnaea stagnalis

Summary Three neuronal systems of the pond snail Lymnaea stagnalis were immunocytochemically investigated at the ultrastructural level with the unlabeled peroxidase-antiperoxidase technique. Preliminary electrophysiological and cell-filling investigations have shown that a cluster of neurons which reacts positively with an antiserum against the molluscan cardio-active peptide FMRFamide, sends axons to the penis retractor muscle. In this muscle anti-FMRF-amide (aFM) positive axons form neuro-muscular synapses with (smooth) muscle fibers. The morphological observations suggest the aFM immunoreactive system to be involved in peptidergic neurotransmission. In the right parietal ganglion a large neuron (LYAC) is penetrated by aFM positive axons which form synapse-like structures (SLS) with the LYAC. The assumption that the SLS represent the morphological basis for peptidergic transmission is sustained by the observation that iontophoretical application of synthetic FMRFamide depolarizes the LYAC. The axons of a group of pedal anti-vasopressin (aVP) positive cells run in close vicinity to the cerebral ovulation (neuro-)-hormone producing cell system (CDC system) Synapses or SLS between the two systems were not observed. The fact that (bath) application of arg-vasopressin induces bursting in the CDC, may indicate that the vasopressin-like substance of the aVP cells is released non-synaptically.     

Distribution of myosin and the glial fibrillary acidic protein (GFA Protein) in rat spinal cord and in the human frontal cortex as revealed by immunofluorescence microscopy

Summary The glial fibrillary acidic (GFA) protein and myosin were localized in rat spinal cord and human frontal cortex using specific antibodies against GFA protein from human spinal cord and highly purified smooth myosin from chicken gizzard by means of an indirect immunofluorescence microscopical approach. A strong GFA protein and myosin immunoreactivity was found in astrocytes of the white and grey matter and in the external glial limitans membrane. The very fine branches of astrocytic processes stained with antiGFA protein, but not with anti-myosin. Similar results were obtained with the human frontal cortex, where myosin antibodies failed to reveal the very fine branches of protoplasmic astrocytes.As a whole, staining with the GFA protein antiserum was more crisp than with the myosin antibody.Thanks are due to Professor J.R. Wolff, Max-Planck Institute for Biophysical Chemistry, Göttingen, for stimulating discussions, to Ursula König, Christa Mahlmeister and Renate Steffens for skilful technical assistance, and to Heidi Waluk for the photographic workSupported by grants from Deutsche Forschungsgemeinschaft (Br 634/1, Dr 91/1, Un 34/4, Ste 105/19)Dedicated to Prof. Dr. med. H. Leonhardt on the occasion of his 60. birthday     

Theoretical studies on animal orientation. I. Methodological appraisal of classifications

Research on animal orientation shows a persistent lack of integration. Theories entertained in different “schools” are couched in incommensurable terms. The underlying definitions mostly do not satisfy elementary canons of methodology, and this results in a confusion of empirical and conceptual problems. Application of basic methodology shows that current classifications of orientation patterns are logically incomplete.Moreover, allegedly distinct kinds of orientation wrongly show logical dependencies resulting from poor definitions. Reference to physiological mechanisms, beyond stimuli and responses, must be omitted from definitions for orientation patterns. Likewise, orientation must not be made functional (adaptive) by definition. Vagueness is to some extent unavoidable in general theories.     

Freeze-fracturing in ultrahigh vacuum at -196 degrees C

Conventional freeze-etching is carried out in a vacuum of approximately 10(-6) torr and at a specimen temperature of -100 degrees C. The relatively poor topographic resolution of most freeze-etch replicas, and the lack of complementarity of morphological details in double replicas have been thought to be caused by structural distortions during fracturing, and radiation damage during replication. Both phenomena can be reduced by lowering the specimen temperature. To prevent condensation of residual gases (especially H2O) on the fracture faces at lower specimen temperature, an improved vacuum is required. Therefore, an ultrahigh vacuum freeze-fracture apparatus has been developed which allows fracturing and Pt/C-shadowing of specimens at -196 degrees C while maintaining a vacuum of 10(-9) torr. It consists of a modified Balzers BA 350 ultrahigh vacuum (UHV) unit, equipped with an airlock which enables the input of nonhoar-frosted specimens directly into the evacuated bell jar. A comparison of the paracrystalline plasmalemma structure in yeast cells portrayed by the conventional technique and by UHV-freeze-fracturing at -196 degrees C shows the improved topographic resolution which has been achieved with the new technique. The improvement is explained by less structural distortions during fracturing at lower temperatures. The particles of the paracrystalline regions on the P face are more regularly arranged and exhibit a craterlike substructure which corresponds with a ringlike depression in the E face. The optical diffraction patterns of these paracrystalline regions demonstrate the improvement of the structural record by showing well-defined third- and fourth-order spots.     

Transparent Golgi Impregnations: A Way to Examine Both Details of Cellular Processes and Components of the Nerve Cell Body

A method is described by which the precipitate that normally fills impregnated cells in Golgi preparations is confined to a thin and transparent scattering of fine particles that defines the somata and cellular processes. The coating is stable enough to withstand counterstaining and thus makes possible direct evaluation of structural features not only of cellular processes but also of cytoplasmic components.     

Molecular variants of human papillomavirus type 16 from four continents suggest ancient pandemic spread of the virus and its coevolution with humankind.

We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval biopsy, 2 penile biopsy, 2 anal biopsy, and 1 vaginal biopsy sample and two cell lines. The specimens were taken from patients in four countries--Singapore, Brazil, Tanzania, and Germany. The sequence of a 364-bp fragment of the long control region of the virus revealed 38 variants, most of which differed by one or several point mutations. Phylogenetic trees were constructed by distance matrix methods and a transformation series approach. The trees based on the long control region were supported by another set based on the complete E5 protein-coding region. Both sets had two main branches. Nearly all of the variants from Tanzania were assigned to one (African) branch, and all of the German and most of the Singaporean variants were assigned to the other (Eurasian) branch. While some German and Singaporean variants were identical, each group also contained variants that formed unique branches. In contrast to the group-internal homogeneity of the Singaporean, German, and Tanzanian variants, the Brazilian variants were clearly divided between the two branches. Exceptions to this were the seven Singaporean isolates with mutational patterns typical of the Tanzanian isolates. The data suggest that HPV-16 evolved separately for a long period in Africa and Eurasia. Representatives of both branches may have been transferred to Brazil via past colonial immigration. The comparable efficiencies of transfer of the African and the Eurasian variants to the New World suggest pandemic spread of HPV-16 in past centuries. Representatives of the African branch were possibly transferred to the Far East along old Arab and Indonesian sailing routes. Our data also support the view that HPV-16 is a well-defined virus type, since the variants show only a maximal genomic divergence of about 5%. The small amount of divergence in any one geographic location and the lack of marked divergence between the Tanzanian and Brazilian African genome variants two centuries after their likely introduction into the New World suggest a very slow rate of viral evolution. The phylogenetic tree therefore probably represents a minimum of several centuries of evolution, if not an age equal to that of the respective human races.     

Hyperostotic fish bones (“Tilly bones”) from presumably Pliocene phosphorites of the Lake Manyara area,northern Tanzania

PalZ - Hyperostotic fish bones from the presumable Pliocene phosphate-bearing deposits along Lake Manyara, Tanzania, are described. In contrast to marine occurrences of this kind, the pathological...     

Effects of L-proline and post-plating temperature treatment on Maize (Zea mays L.) anther culture

Summary Comparison of different post-plating temperature regimes with a control treatment (27° C) revealed that a short-term cold (8/14°C:2/2 days or 14°C:4 days) as well as a heat treatment (30°C:14 days) increased the production of embryro-like-structures (ELS) from cultured maize anthers. The beneficial effects of short-term cold treatments were magnified 2–3 times when L-proline (PROL) was added to the induction medium (125–500 mg/L). In the best treatment (14°C:4 days, 125 mg/L L-proline) one genotype produced 143.5 ELS/100 anthers. Anthers subjected to high temperature (30°C:4 days, 30°C:7 days, 30°C:14 days) generally showed a lower response than did cold treated anthers, although genotypic differences were observed. Regeneration frequency did not appear to be affected by the presence of L-proline in the induction medium.Abbreviations ELS Embryo-like-structures - PROL L-proline