Time course of lipolytic activity and lipid peroxidation after whole-body gamma irradiation of rats

The content of fluorescing products of lipid peroxidation (LFP) and hormone-stimulated lipolytic activity were determined in rat epididymal adipose tissue during a 29-day interval after whole-body gamma irradiation. An increase in LFP was accompanied by a decrease in lipolytic activity. It is suggested that these effects are interrelated and that the decrease in lipolysis in irradiated, semi fasting rats is an additional deteriorating factor leading to death in some animals.     

Coenzyme F430 as a possible catalyst for the reductive dehalogenation of chlorinated C1 hydrocarbons in methanogenic bacteria

Corrinoids, such as aquocobalamin, methylcobalamin, and (cyanoaquo)cobinamide, catalyze the reductive dehalogenation of CCl4 with titanium(III) citrate as the electron donor [Krone et al. (1989) Biochemistry 28, 4908-4914]. We report here that this reaction is also effectively mediated by the nickel-containing porphinoid, coenzyme F430, found in methanogenic bacteria. Chloroform, methylene chloride, methyl chloride, and methane were detected as intermediates and products. Ethane was formed in trace amounts, and several as yet unidentified nonvolatile compounds were also generated. The rate of dehalogenation decreased in the series of CCl4, CHCl3, and CH2Cl2. With coenzyme F430 as the catalyst, the reduction of CH3Cl to CH4 proceeded more than 50 times faster than with aquocobalamin. Cell suspensions of Methanosarcina barkeri were found to catalyze the reductive dehalogenation of CCl4 with CO as the electron donor (E'0 = -0.524 V). Methylene chloride was the main end product. The kinetics of CHCl3 and CH2Cl2 formation from CCl4 were similar to those with coenzyme F430 or aquocobalamin as catalysts and titanium(III) citrate as the reductant.     

Individualgeschichte und Gesangsauspr?gung beim Star (Sturnus vulgaris) in einer Kolonie

Zusammenfassung Die Lautäußerungen der Stare können in Gesangsstrophen und Pfeiflaute unterteilt werden. Pfeiflaute sind kurz (bis 2 s) und einfach gebaut, während die Strophen wesentlich länger andauern (meist über 20 s) und sich aus zahlreichen komplex gebauten Untereinheiten zusammensetzen. In einer Kolonie bei Frankfurt am Main, in der die Individuen durch Farbringe gekennzeichnet sind, wurde der individuelle Variationsspielraum der Lautäußerungen analysiert. In den Feinstrukturen der Pfeifthemen glichen sich die Koloniemitglieder weitgehend aneinander an. In den Feinstrukturen der Motivtypen der Gesangsstrophen traten dagegen große individuelle Unterschiede auf. , die während Jahren in der gleichen Kolonie brüteten, sangen nur sehr wenige gemeinsame Motivtypen. Die Repertoiregröße variierte zwischen 17–39 Motivtypen. Im Herbstgesang traten 5 bisher noch nicht beobachtete Motivtypen auf. Es gibt somit deutliche Hinweise darauf, daß auch der adulte Star neue Laute erlernen kann.

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Individual history and song structure of Starlings (Sturnus vulgaris) living in a colony

Summary Starling's song can be divided into warbling and whistles. Whistles have a short and simple structure, whereas warbling is sung in long sequences (most often more than 20 s). In the warbling one can distinguish many different subunits (repetition of motifs). The individual variability of songs was studied in a colony near Frankfurt/Main in West Germany, where starlings were colour banded since 1969. The following results were obtained:Birds from the same colony uttered nearly identical or very similar microstructures in the species-specific whistle themes. Different to the whistle themes very distinct individual differences characterized the warbling. Only a few motif types were common among colony members. The individual repertoire size ranged from 17 to 39 motif types. Comparison of the song of one individual between the breeding season and the following autumn shows that motifs, which were not observed during spring occurred in the autumn. This observation is a hint that starlings are capable to learn new motif types even as adults.

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Stipendium der Alexander-von-Humboldt-Stiftung     

Ultrastructure of the kidney of a South American caecilian,Typhlonectes compressicaudus (Amphibia,Gymnophiona)

Summary The ultrastructure of the distal nephron, the collecting duct and the Wolffian duct was studied in a South American caecilian, Typhlonectes compressicaudus (Amphibia, Gymnophiona) by transmission and scanning electron microscopy (TEM, SEM). The distal tubule (DT) is made up of one type of cell that has a well-developed membrane labyrinth established both by interdigitating processes and by interlocking ramifications. The processes contain large mitochondria, the ramifications do not. The tight junction is shallow and elongated by a meandering course. The connecting tubule (CNT) is composed of CNT cells proper and intercalated cells, both of which are cuboidal in shape. The CNT cells are characterized by many lateral interlocking folds. The intercalated cells have a dark cytoplasm densely filled with mitochondria. Their apical cell membrane is typically amplified by microplicae beneath which a layer of globular particles (studs) is found. The collecting duct (CD) is composed of principal cells and intercalated cells, again both cuboidal in shape. The CD epithelium is characterized by dilated intercellular spaces, which are often filled with lateral microfolds projecting from adjacent principal cells. The apical membrane is covered by a prominent glycocalyx. The intercalated cells in the CD are similar to those in the CNT. The Wolffian duct (WD) has a tall pseudostratified epithelium established by WD cells proper, intercalated cells and basal cells. The WD cells contain irregular-shaped dense granules located beneath the apical cell membrane. The intercalated cells of the WD have a dark cytoplasm with many mitochondria; their nuclei display a dense chromatin pattern.Research fellow of the Alexander von Humboldt Foundation     

Microfibrils are a major component of the mesangial matrix in the glomerulus of the rat kidney

Summary Certain secretory cells in the hypophysial pars tuberalis of the Djungarian hamster display marked circannual structural alterations. The present investigation deals with the immunohistochemical properties of this cell group. A distinct TSH-like immunoreactivity was found in secretory cells of this type in the pars tuberalis of animals exposed to long photoperiods, whereas under short photoperiods the TSH-like immunoreactivity was nearly absent. In the pars distalis, the number and distribution of TSH-positive cells did not differ significantly between animals maintained under long and under short photoperiods. LH-and FSH-positive cells could not be detected in the pars tuberalis, but they are clearly present in the pars distalis of both groups of hamsters. Our immunocytochemical results suggest that photoperiodic stimuli influence the secretory activity of TSH-like immunoreactive cells in the pars tuberalis. A connection with the neuroendrocrine-thyroid axis is discussed.The study was supported by the Deutsche Forschungsgemeinschaft (Wi 558/3-1, Pe 134/2-4)     

Structure-function analysis with tissue-type plasminogen activator. Effect of deletion of NH2-terminal domains on its biochemical and biological properties

Tissue-type plasminogen activator (t-PA) is a mosaic protein containing several distinct structural domains attached to the serine protease catalytic unit present at its COOH terminus. To investigate structure-function relationships in t-PA, we deleted the NH2-terminal domains, finger and epidermal growth factor, by genetic engineering. The genes for the parent and mutant t-PA were expressed in a bovine papilloma virus-dependent mammalian cell system. The secreted proteins were purified to homogeneity. The mutant protein was processed to the expected size of about 60 kDa compared to approximately 68 kDa for the parent t-PA, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fibrin autography. While the mutant t-PA had amidolytic activity comparable to native t-PA, it did not bind appreciably to fibrin. Consequently, fibrin-dependent enzymic activity, i.e. plasminogen activation in the presence of soluble fibrin and fibrinolysis were lower than with native recombinant t-PA. The effect of deletion of NH2-terminal domains on the plasma half-life (t1/2) was investigated by injecting native and mutant t-PA into mice. While the majority of the t-PA disappeared initially with a t1/2 of about 2 min, mutant t-PA cleared at a much slower rate with t1/2 of about 50 min. These findings suggest that the NH2-terminal domains of t-PA not only determine its specificity for binding to fibrin but also mediate its clearance from plasma in vivo. Furthermore, the catalytic unit in t-PA seems to function autonomously.     

Emotional and behavioral reactions to facially deformed patients before and after craniofacial surgery

The present experiment investigated whether observers' emotional and behavioral reactions to facially deformed patients could be substantially improved by surgical procedures conducted by well-trained specialists in an experienced multidisciplinary team. Also investigated was the hypothesis that emotional states mediate the effects of physical attractiveness and facial deformity on social interaction. Twenty patients between the ages of 3 months and 17 years were randomly selected from over 2000 patients' files of Kenneth E. Salyer of Dallas, Texas. Patient diagnoses included facial clefts, hypertelorism, Treacher Collins syndrome, and craniofacial dysostoses (Crouzon's and Apert's syndromes). Rigorously standardized photographs of patients taken before and after surgery were shown to 22 "naive" raters ranging in age from 18 to 54 years. Raters were asked to predict their emotional and behavioral responses to the patients. These ratings indicated that observers' behavioral reactions to facially deformed children and adolescents would be more positive following craniofacial surgery. Similarly, the ratings indicated that observers' emotional reactions to these patients would be more positive following surgery. The results are discussed in terms of current sociopsychologic theoretical models for the effects of attractiveness on social interaction. A new model is presented that implicates induced emotional states as a mediating process in explaining the effects of attractiveness and facial deformity on the quality of social interactions. Limitations of the current investigation and directions for future research are also discussed.     

Microtubule-associated protein 2 (MAP2)-immunoreactive neurons in the retina of Bufo marinus: colocalisation with tyrosine hydroxylase and serotonin in amacrine cells

Summary Neuron populations in the retina of the toad, Bufo marinus, were labelled with a monoclonal antibody raised against microtubule-associated protein 2 (MAP2). A subpopulation of cones, probably corresponding to the blue-sensitive small single cones, large diameter amacrine cells in the most proximal row of the inner nuclear layer and some large ganglion cells in the ganglion cell layer were labelled. Double labelling experiments were carried out to establish the colocalisation of MAP2 with known putative transmitter substances of the anuran amacrine cells. MAP2 was colocalised in a subpopulation of serotonin-immunoreactive and in all tyrosine hydroxylase-immunoreactive amacrine cells. The results indicate, that the MAP2 content in the neurons of the anuran retina can be correlated with other well-defined neurochemical and/or physiological properties.On leave from Department of Zoology, Attlia József University, Szeged, Hungary     

Rhizome dynamics and resource storage in Phragmites australis

Seasonal changes in rhizome concentrations of total nonstructural carbohydrates (TNC), water soluble carbohydrates (WSC), and mineral nutrients (N, P and K) were monitored in two Phragmites australis stands in southern Sweden. Rhizome biomass, rhizome length per unit ground area, and specific weight (weight/ length ratio) of the rhizomes were monitored in one of the stands.Rhizome biomass decreased during spring, increased during summer and decreased during winter. However, changes in spring and summer were small (< 500 g DW m-2) compared to the mean rhizome biomass (approximately 3000 g DW m^–2). Winter losses were larger, approximately 1000 g DW m-2, and to a substantial extent involved structural biomass, indicating rhizome mortality. Seasonal changes in rhizome length per unit ground area revealed a rhizome mortality of about 30% during the winter period, and also indicated that an intensive period of formation of new rhizomes occurred in June.Rhizome concentrations of TNC and WSC decreased during the spring, when carbohydrates were translocated to support shoot growth. However, rhizome standing stock of TNC remained large (> 1000 g m^–2). Concentrations and standing stocks of mineral nutrients decreased during spring/ early summer and increased during summer/ fall. Only N, however, showed a pattern consistent with a spring depletion caused by translocation to shoots. This pattern indicates sufficient root uptake of P and K to support spring growth, and supports other evidence that N is generally the limiting mineral nutrient for Phragmites.The biomass data, as well as increased rhizome specific weight and TNC concentrations, clearly suggests that reloading of rhizomes with energy reserves starts in June, not towards the end of the growing season as has been suggested previously. This resource allocation strategy of Phragmites has consequences for vegetation management.Our data indicate that carbohydrate reserves are much larger than needed to support spring growth. We propose that large stores are needed to ensure establishment of spring shoots when deep water or stochastic environmental events, such as high rhizome mortality in winter or loss of spring shoots due to late season frost, increase the demand for reserves.