Importance deVernonia guineensis Benth. dans l'alimentation de quelques Fourmis de savane

Résumé La ComposéeVernonia guineensis Benth., abondante dans les savanes préforestières de Côte d'Ivoire, fleurit quelques semaines après le passage des feux de brousse. Plusieurs espèces de Fourmis sont récoltées régulièrement sur la plante: ce sont surtoutCamponotus acvapimensis et unCremastogaster du genreAcroclia.Les Fourmis se nourrissent de sécrétions sucrées qui suintent au niveau des bractées des jeunes capitules, mais pratiquent également l'élevage d'Homoptères.Divers types de constructions sont décrits et, en particulier, les loges édifiées parC. acvapimensis pour abriter un Jassidæ:Selenocephalus sp.L'influence de l'environnement végétal sur la faune myrmécologique exploitantV. guineensis est mise en évidence.

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Summary Vernonia guineensis Benth. (Compositæ). common in the forest-savanna mosaic of Ivory Coast, blooms a few weeks after the fires. Several species of Ants are collected then on the forb; especiallyCamponotus acvapimensis and a species ofCremastogaster (Acroclia).These ants feed on seepings from the young flower heads, and search for exsudates of Homopterans.Various buildings are described, particularly shelters made byC. acvapimensis for the leaf—hopperSelenocephalus sp.Influence of botanical environment on the ants exploitingV. guineensis is shown.

     

XX/XO-Mosaik bei einem männlichen Individuum mit Kleinwuchs und Hypospadie

Zusammenfassung Bei einem normal intelligenten, kleinwüchsigen, 219/12 jährigen Mann mit Hypospadie, fraglicher rudimentärer Vagina und hypergonadotropem Hypogonadismus findet man bei der Biopsie des nur 7 ml großen linken Hodens eine gleichförmige tubuläre Atrophie mit Fehlen des Keimepithels und eine diffuse, kleinherdige Leydigzellwucherung. Sex-Chromatin in den Leydigzellen, im Mundabstrich und Drumsticks negativ. Karyotyp in den Lymphocyten und im Knochenmark normal weiblich (46,XX), in den Fibroblasten jedoch 45,XO.Somit weist dieser Patient Testesgewebe auf, das Y-Chromosom ist aber unauffindbar. Zur Klärung dieser Diskrepanz scheint das Vorhandensein einer dritten, zahlenmäßig stark in den Hintergrund tretenden, ein Y enthaltenden Zellpopulation die naheliegendste Hypothese zu sein.Eine Zwillingsschwester kam im Neugeborenenalter ad exitum; die Blutgruppenuntersuchungen beim Patienten und seiner Familie machen aber einen Blutchimärismus sehr unwahrscheinlich.Das klinische Bild unseres Patienten ist vollkommen verschieden von demjenigen, das beim XX/XO-Mosaik üblicherweise beobachtet wird und läßt sich auch vom klassischen Klinefelter-Syndrom deutlich abgrenzen. Es zeigt Ähnlichkeiten mit einigen Fällen von XO/XY-Mosaik.

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Summary In a normally intelligent man of 219/12 years the following main physical findings were present: short stature, hypospadias, possibly a rudimentary vagina, hypergonadotropic hypogonadism, small testis (7 ml) with tubular dystrophy consisting in absence of germinal epithelium and localized proliferation of Leydig's cells. Sex chromatin in buccal mucosa cells was negative; no drumsticks were found in neutrophils. The karyotype in lymphocyte cultures and bone-marrow preparations was 46,XX; in several independent fibroblast cultures 45,XO.The most likely explanation for the presence of testicular tissue seems to be the existence of an undiscovered cell population containing a Y-chromosome.A twin sister of the patient died in early infancy; blood group investigations gave no indications for the presence of blood chimerism.The clinical picture of this patient is entirely different from that of the usual XX/XO mosaics, it also clearly differs from Klinefelter's syndrome but shows some similarities to cases of XO/XY mosaicism.

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Direktor: Prof. Chr. Hedinger     

Die Fertilität polyploiderBeta-Rüben und ihre Beeinflussung durch ernährungsphysiologische Faktoren

Ohne ZusammenfassungMit 4 Abbildungen     

Anatomical Studies of Haustorium Ontogeny and the Remarkable Mode of Penetration of the Haustorium in Nuytsiafloribunda (Labill.) R. Br.

The development and structure of secondary haustoria of Nuytsia floribunda are described and compared with other Santalalean haustoria. After establishing contact with the host root, cortical folds of the haustorium grow around the root in separate directions and fuse forming a ring around it. At an early stage of development, meristematic tissue differentiates in the interior proximal part of the haustorium. Zones of collapsed layers are present in the outer cortical region. Subsequently, in the proximal part, two vascular cores, two lysigenous cavities and extensive masses of sclerenchyma develop prior to penetration of the host root. The sclerenchymatous cells form a characteristic structure, described as the sclerenchyma prong. During penetration the intrusive part of the haustorium reaches not only the host xylem but continues growing downwards until it entirely splits the host root. Comparable to a guillotine, the sclerenchyma prong is directly involved in this remarkable process. The sclerenchyma prong finally lies in the distal part of the haustorium. Following this mechanical slicing of the host root, tube-like cells of the intrusive part actively penetrate the host xylem in an axial direction.     

Modulation of IL-4-induced human IgE production in vitro by IFN-gamma and IL-5: the role of soluble CD23 (s-CD23)

IL-4 specifically induced IgE production by peripheral blood lymphocytes or by tonsil or spleen cells from healthy donors. IL-4-induced IgE synthesis was dependent on CD4+ T cells and monocytes and was blocked by IFN-gamma, IFN-alpha, and prostaglandin E-2 (PGE-2). These substances also inhibited IL-4-induced CD23 expression and subsequent release of soluble CD23 (s-CD23). In addition, IgE production was blocked by F(ab')2 fragments of an mAb against CD23. In contrast, IL-5 enhanced IL-4-induced IgE production, provided IL-4 was added at nonsaturating concentrations. This increase in IgE production correlated quantitatively with an enhanced release of s-CD23. Collectively, these results indicate that there is a correlation between s-CD23 release and IgE production. However, s-CD23 fractionated from supernatants of the lymphoblastoid cell line RPMI-8866 was ineffective in inducing IgE production in the absence of IL-4, but acted synergistically with suboptimal concentrations of IL-4. In addition, it is demonstrated that alloreactive T-cell clones produced varying concentrations of IL-4, IL-2, or IFN-gamma upon stimulation. Only supernatants of 2/4 of these T-cell clones induced a low degree of IgE synthesis, but in the presence of anti-IFN-gamma antibodies, all four supernatants induced a strong induction of IgE production. This IgE synthesis was blocked specifically by anti-IL-4 antibodies, indicating that IL-4 is the sole inducer of IgE synthesis. Our findings demonstrate that IL-4-induced IgE production involves complex interactions of T cells, B cells, and monocytes and is positively modulated by IL-5 and s-CD23 but down-regulated by IFN-gamma, IFN-alpha, and PGE-2, respectively.     

Fragmentation of bovine chromogranin A by plasma kallikrein

Chromogranin A has been reported to be processed in vivo by an as yet undefined proteinase(s) suggesting that it is a precursor of biologically active peptides such as pancreastatin. In this study, plasma kallikrein was used as a model proteinase to identify the cleavage sites exposed in bovine parathyroid chromogranin A. Purified bovine parathyroid chromogranin A was digested with human plasma kallikrein. The proteolytic fragments produced were isolated by HPLC and chemically characterized by amino acid composition and sequence analysis. The combined results indicate that the enzyme has preference for specific single Arg residues, cutting C-terminal to this amino acid, although certain pairs of basic sites were also cleaved. The characterized fragments were released in a selective manner from the whole molecule with rapid production of the fragments covering positions 1-247 and 352-358.     

Melanin concentrating hormone. V. Isolation and characterization of alpha-melanocyte-stimulating hormone from frog pituitary glands

The structure of alpha-melanocyte-stimulating hormone (alpha-MSH) has been determined in the pars intermedia of the frog Rana ridibunda. Pulse-chase labeling of frog neurointermediate lobes with selective amino acids revealed that the composition of frog alpha-MSH is similar to that of alpha-MSH from all mammalian species yet studied. Tryptic mapping of nexly synthetized alpha-MSH generated two fragments with the following amino acid composition: (T1) Trp, Pro, Lys, Gly, Val and (T2) Tyr, Arg, Phe, His, Ser, Glu. Concurrently, alpha-MSH was purified from 100 neurointermediate lobes to apparent homogeneity by reverse-phase HPLC. The sequence of the peptide determined by automated Edman degradation was Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val. The structure of frog alpha-MSH is thus identical to mammalian des-N alpha-acetyl alpha-MSH and differs from the sequence of toad (Xenopus laevis) alpha-MSH only by the first residue (Ser instead of Ala). These results confirm that the sequence of alpha-MSH has been highly preserved during evolution.