Pnoepyga immaculata n. sp., eine neue bodenbewohnende Timalie aus dem Nepal-Himalaya

Zusammenfassung Pnoepyga immaculata n. sp. lebt im Areal der beiden anderenPnoepyga-Artenalbiventer (Hodgson 1837) undpusilla Hodgson 1845 und wurde durch ihren markant abweichenden Territorialgesang entdeckt. Sie besitzt eine kurze silberhelle Strophe aus kurzen, in gleichmäßigen Abständen gereihten Pfiff-Elementen, die in der Frequenz leicht abfällt. Neben der Stimme liegen die wesentlichen diagnostischen Merkmale nach jetzigem Kenntnisstand gegenüber sympatrischenalbiventer in wenig größerem Schnabel, der Fleckenlosigkeit von Oberseite, Kopf und Flügeldecken, gegenüberpusilla in den größeren Körperabmessungen, gegenüber sympatrischenalbiventer undpusilla im schwachen grünlichen Schimmer der Oberseite und in der länglichen Schuppung der Unterseite. Es bestehen keine Proportionsunterschiede zwischenimmaculata undalbiventer/pusilla einerseits wie auch nicht zwischen diesen beiden andererseits. Bis jetzt wurden 4 Belegstücke (SammlungenKoelz, Diesselhorst, Martens) und eine durch Bandaufnahme gesicherte Beobachtung zwischen Dhaulagiri in Mittelwest-Nepal bis nahe der Ost-Grenze Nepals bekannt.P. immaculata lebt zur Brutzeit in enger Nachbarschaft mitP. albiventer undP. pusilla, ist jedoch vonalbiventer vertikal getrennt bei nachgewiesenem Kontakt, vonpusilla durch Bevorzugung trockeneren Waldunterwuchses abseits von Bächen. Schon jetzt mußimmaculata als gefährdete Art eingestuft werden, da Waldvegetation in der zur Brutzeit bevorzugten Höhenstufe zwischen 2100 und 3100 m in Nepal weitgehend vernichtet worden ist.

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Pnoepyga immaculata n. sp., a new ground living wren-babbler from the Nepal Himalayas (Timaliidae)

Summary P. immaculata n. sp. was discovered by its voice which strongly differs from the two other sympatric species,albiventer (Hodgson 1837) andpusilla Hodgson 1845. As a territorial song, it displays a silvery strophe arranged of short, more or less regularly spaced whistling notes (fig. 7a–d), slightly descending in pitch. The strophe is about 2 s long. Besides the distinct voice, the essential diagnostic characters in comparison toP. albiventer are the slightly larger bill, plain head, upper side and wing coverts (fig. 1a–d, 2, 4a–d), in comparison topusilla the larger body size (fig. 1i–m), in comparison to sympatricalbiventer andpusilla the slightly olive tinge of the upper side (against warm dark brown in both others, fig. 1e–m), and the more longish scaly feathers of the lower side (against stout scaly appearance in both others, fig. 1 a–d). These characters hold true at least in Central and Eastern Himalayan populations of the respective species. There do not exist proportional differences in the relations of any part of the body betweenimmaculata andpusilla and not between the latter ones as well. Heretofore, 4 museum specimens are known (Koelz Coll.,Diesselhorst Coll.,Martens Coll.) from West-central (Thakkhola, type locality) and East Nepal (Ting Sang La), 3 of them from the presumed breeding grounds (2100–3100 m), one from the winter quarters in the Terai lowlands. A field observation close to the Darjeeling border in far East Nepal is verified by a tape-recording.P. immaculata embarasses the biologist and systematist because it lives in close neighbourhood of the similar speciesalbiventer andpusilla. It must have been overlooked by its apparent scarcity and overall similarity to both other species of the genus. Slight ecological differences rather correspond to the vertical distribution ofalbiventer, which populates a higher forest belt. But both have already been found on territory at close range.P. pusilla inhabits different microbiotopes, especially the close proximity of running water in the same altitudinal belt asimmaculata. When discovered,P. immaculata is to be classified already as an endangered species. Forest vegetation of its preferred altitude is already greatly reduced in the Central and Eastern Nepal Himalayas. To get a more detailed information on its general distribution and biology in order to quickly arrange protected areas and thus to guarantee the survival ofP. immaculata, should be the urgent next step.

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Results of the Himalaya Expeditions ofJ. Martens, No. 163. — For No. 162 see: Stuttgarter Beitr. Naturkde. (A) 453: 1–46, 1990.     

Enantiospecific quantification of hexobarbital and its metabolites in biological fluids by gas chromatography/electron capture negative ion chemical ionization mass spectrometry.

A highly sensitive and specific assay based on gas chromatography/electron capture negative ion chemical ionization mass spectrometry has been developed for the analysis of the enantiomers of hexobarbital and its major metabolites in human urine and plasma. S-(+)-(5-2H3)hexobarbital and R-(-)-(5-2H3)hexobarbital were synthesized for clinical studies along with (+/-)-(1,5-2H6)hexobarbital and the deuterated major metabolites for use as internal and reference standards. Hexobarbital enantiomers and their metabolites were analyzed after pentafluorobenzyl and trimethylsilyl derivatization, following solid-phase extraction from plasma and urine. Intense negative ion spectra were observed for all of the derivatives. The base peak in the spectra corresponded to the M-pentafluorobenzyl anion [M-PFB]- except for 1,5-dimethylbarbituric acid, where M-. was the most abundant ion. The applicability of the method was demonstrated by following the plasma concentration-time profiles and urinary excretion in a male extensive metabolizer of mephenytoin who was given a pseudoracemic oral dose of hexobarbital containing equal 50 mg amounts of S-(+)-2(H0)hexobarbital and R-(-)-(2H3)hexobarbital. Marked stereoselective disposition was observed, with the R-(-)-enantiomer being more efficiently metabolized, primarily by alicyclic oxidation and ring cleavage.     

Induction of erythropoietin responsiveness in murine hematopoietic cells by the gag-myb-ets-containing ME26 virus.

ME26 virus, which was generated by inserting the coding region of the acute avian leukemia-inducing virus E26 into a murine retrovirus vector, encodes a 135-kDa gag-myb-ets fusion protein. Amphotropic murine leukemia virus pseudotypes of ME26 virus induce a high incidence of erythroleukemia 2 to 4 months after injection into newborn NFS/N mice. Spleen cells from the majority of these mice proliferate to high levels in the presence of the erythroid hormone erythropoietin (Epo) and can easily be established as permanent Epo-dependent cell lines. The cell lines contain multiple copies of ME26 viral DNA and express viral message and protein. An Epo receptor mRNA of normal size can be detected in these cells, and binding studies reveal a single class of lower-affinity Epo receptor with an affinity for Epo that is in the range of that previously reported for erythroid cells. The ME26 virus-induced Epo-dependent cell lines, however, appear more immature than previously described erythroid cell lines and more closely resemble early hematopoietic precursor cells, suggesting that the virus may be activating the Epo receptor in hematopoietic cells that do not normally express it. Consistent with this idea, we are able to infect an interleukin-3-dependent myeloid cell line, FDC-P2, with ME26 virus and convert it to Epo dependence. The ME26 virus-infected FDC-P2 cells, even before growth on Epo, showed a large increase in the amount of Epo receptor mRNA. However, no ME26 viral integrations can be detected adjacent to the Epo receptor gene, indicating that the virus is not activating the Epo receptor gene by promoter/enhancer insertion. Our results are more consistent with the hypothesis that the gag-myb-ets-encoded viral fusion protein, which is known to bind DNA, is directly or indirectly activating the expression of the Epo receptor gene in these cells.     

Effects of glutathione and of cysteine on intestinal absorption of selenium from selenite

The influence of glutathione (1 mmol/L) (GSH) on in vitro mucosal uptake and in vivo absorption of⁷⁵Se-labeled selenite (10 μmol/L) was investigated in rat jejunum. For comparison, the effect ofl-cysteine (1 mmol/L) on in vivo absorption of⁷⁵Se-labeled selenite was also studied. In the in vitro, uptake experiments, only the mucosal surface was exposed to the incubation medium for 3 min. For the in vivo experiments, a luminal perfusion technique was employed. GSH inhibited in vitro mucosal Se uptake, whereas absorption in vivo was stimulated by GSH.l-Cysteine also stimulated in vivo Se absorption, confirming former in vitro mucosal uptake experiments. Thus, unlikel-cysteine, GSH affected in vitro and in vivo absorption of Se from selenite differently. Enzymatic cleavage of products of the reaction of selenite with GSH occuring more efficiently under in vivo than in vitro conditions may be a prerequisite for the stimulatory effect of GSH on Se absorption. This apparently does not apply to the stimulatory effect of cysteine. Since, GSH occurs in the intestinal lumen under physiological conditions, it may contribute to the high bioavailability of Se from selenite.     

Stimulation of mucosal uptake of selenium from selenite by some thiols at various sites of rat intestine

The influence of several thiols (conc. 1 mmol/L) on mucosal uptake of⁷⁵Se from⁷⁵Se-labeled selenite (conc. 10 μmol/L) across the brush border of rat jejunum and cecum was investigated in vitro using a short-term uptake technique.l-Cysteine (l-Cys) stimulated⁷⁵Se uptake in the mid- and distal jejunum and cecum, but not in the proximal jejunum. The effect was maximal in the distal jejunum.d-Cys was less effective in the jejunum and similarly effective in the cecum.l-Leucine (l-Leu) andl-glutamic acid significantly reduced the stimulatory effect ofl-Cys on Se uptake in the distal jejunum, whereas the respective effect ofd-Cys was not diminished byl-Leu. Cysteamine stimulated mucosal⁷⁵Se uptake at all intestinal sites tested, whereas the effect of mercaptopyruvate was restricted to the distal jejunum. Thioglycolate also enhanced⁷⁵Se uptake in the distal jejunum. The stimulatory effects ofl-Cys, mercaptopyruvate, and thiologlycolate were Na⁺-dependent, whereas the effect of cysteamine also occurred in the absence of Na⁺. Mercaptosuccinate,d-penicillamine, ergothioneine, and thiosulfate did not enhance mucosa⁷⁵Se uptake. It is concluded from these findings that the reaction of some thiols with selenite results in Se compounds that are rapidly absorbed by the intestinal epithelium through various Na⁺-dependent and Na⁺-independent, mechanisms. The high bioavailability of Se from selenite found by others might thus be the result of the presence of thiols in the gastrointestinal tract.     

A comparative study on the formation of citric acid and polyols and on morphological changes of three strains of free and immobilized Aspergillus niger

Summary The formation of citric acid, oxalic acid, erythritol and glycerol by three strains of Aspergillus niger immobilized in calcium alginate was investigated and compared with that of free cells when cultivated in shake flasks under phosphate limitation. Morphological changes were followed using an electron microscope. The production of acids and polyols, the consumption of glucose and fructose, and also the morphological changes were strain-dependent. The results also reflected the influence of long storage of a strain on productivity, morphological behaviour and phosphate consumption. Offprint requests to: H.-J. Rehm     

Differences in lipogenesis in tissues of control and gold-thioglucose obese mice after an isocaloric meal

Lipogenesis was measured in 2 and 5 week gold-thioglucose (GTG) obese mice after a single meal of 0.5 g of standard chow. Compared to control mice the rate of lipogenesis in GTG obese mice, was 4-fold higher in liver and 10-fold higher in white adipose tissue (WAT). In brown adipose tissue (BAT) of GTG-injected mice the lipogenic rate was only 50% of that of controls. These results indicate that the increased lipid synthesis observed in GTG-injected mice is not due solely to hyperphagia and that some other stimuli, such as increased basal insulin levels and/or decreased thermogenesis and insulin resistance in BAT, contribute to the high rates of fat synthesis in this animal model of obesity.     

Effects of cell heterogeneity on production of polypeptide growth factors and mesoderm-inducing activity by Xenopus laevis XTC cells

The Xenopus laevis XTC cell line has been analyzed for the production of polypeptide growth factors and mesoderm-inducing activity. By the use of specific biological assays, it is shown that XTC cells produce a growth factor functionally related to the platelet-derived growth factor (PDGF) and two transforming growth factor (TGF)β-like activities. Mesoderm-inducing activity, as measured on X. laevis ectodermal explants from stage 10 embryos, was found to coelute on a Bio-Gel P-100 column with one of the TGFβ-like activities at an apparent molecular weight of 6–10 kDa. Analysis of the DNA content from XTC cells by flow cytometry demonstrated that the cell line is heterogeneous and consists of both tetraploid and diploid cells. Cloning of the XTC cells and selecting single-cell colonies on the basis of their ability to grow in soft agar resulted in the isolation of several homogeneous, morphologically different clonal derivatives. Analysis of conditioned medium from these clonal derivatives showed that only one of them, the only diploid line among six investigated, produced a strong heat- and acid-stable mesoderm-inducing activity that induced notochord and muscle formation in stage 10 X. laevis ectodermal expiants. The relation between this activity and a recently described TGFβ-like mesoderm-inducing factor obtained from XTC-conditioned medium will be discussed. In conclusion, a clonal cell line derived from X. laevis XTC cells which provides a good source for further characterization of mesoderm-inducing factors has been established.     

Biochemistry and ultrastructure of iridescent virus type 29

Physical and chemical parameters of iridescent virus type 29, isolated from the mealworm, Tenebrio molitor, have been analyzed. The icosahedral capsid is 130–135 nm in diameter and is surrounded by a fringe of coarse filaments. The virus has a buoyant density in CsCl of 1.31 g cm^?3 and contains 20 to 25 structural proteins as analyzed by isoelectric focusing and SDS-polyacrylamide gel electrophoresis. The DNA has a buoyant density in CsCl of 1.6874 g cm^?3 indicating a G + C content of approximately 28%. The lipid components of this virus differ from those of the host cell; the virus contains about 80% cardiolipin and 20% phosphatidyl choline.     

Dispersal of Acacia cyclops by birds

Summary In South Africa seedlings of the exotic Acacia cyclops grow in clumps. The seedlings occur beneath tall elements, or in bush clumps, of the surrounding indigenous vegetation. The tall shrubs are used as perches by birds, and the pattern of seedling distribution is a result of dispersal of seeds by birds. Germination of A. cyclops seeds was enhanced as a result of passage through the gut of a bird, or by artificial treatments simulating actions taking place in the gut of a bird. We examine properties of the seed, and the funicle which is attractive to birds, in relation to aspects of the life history of A. cyclops and the species' success as an invasive plant in South Africa.