Comparative Seed Dispersal Effectiveness of Sympatric Alouatta guariba and Brachyteles arachnoides in Southeastern Brazil

Martins, M. M.
2006-01-01

ABSTRACT I compared the effectiveness of sympatric brown howlers (Alouatta guariba) and muriquis (Brachyteles arachnoides) as seed dispersers in terms of quantitative and qualitative attributes. I hypothesized that differences in feeding and behavioral patterns between these large-bodied folivorous/frugivorous primates would lead to dissimilarities in their effectiveness as endozoochoric seed dispersal agents. The study was carried out in a semideciduous forest fragment of Fazenda Barreiro Rico, southeastern Brazil. Through behavioral sampling of frugivory and defecation events as well as analyses of fecal samples, I determined that A. guariba dispersed fewer species and produced a lower proportion of dung with intact seeds than B. arachnoides. There was no difference between the number of...

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Visit of Ambassadors from Latin America, Portugal and Spain to SM18.

Loez, Patrice
2002-06-03

Left to right: Prof. Juan Antonio Rubio, Head of the Education and Technology Transfer Division; H.E. Mr Gustavo Albin, Ambassador, Permanent Representative of Mexico in Geneva; H.E. Mr Joaqun Prez-Villanueva y Tovar, Ambassador, Permanent Representative of Spain in Geneva; H.E. Mr Alvaro de Mendona e Moura, Ambassador, Permanent Representative of Portugal in Geneva, Dr Norbert Siegel, Insertion, Correctors and Protection Group, LHC division; H.E. Mr Juan Enrique Vega, Ambassador, Permanent Representative of Chile in Geneva; Mr Rodrigo Espinosa, Counsellor, Permanent Mission of Chile in Geneva; H.E. Mr Horacio Emilio Solari, Ambassador, Permanent Representative of the Republic of Argentina in Geneva; Dr John Ellis, Adviser for Non-Member State Relations and Mr Enrique Ochoa, Third Secretary, Permanent Mission of Mexico in Geneva.

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Expression of Ghrelin and Its Functional Receptor, the Type 1a Growth Hormone Secretagogue Receptor, in Normal Human Testis and Testicular Tumors

Gaytan, Felice; Barreiro, M. L.; Caminos, Jorge E.; Chopin, Lisa K.; Herington, Adrian C.; Morales, Concepcion
2004-01-01

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has been primarily linked to the central neuroendocrine regulation of GH secretion and food intake, although additional peripheral actions of ghrelin have also been reported. In this context, the expression of ghrelin and its cognate receptor has been recently demonstrated in rat testis, suggesting a role for this molecule in the direct control of male gonadal function. However, whether this signaling system is present in human testis remains largely unexplored. In this study we report the expression and cellular location of ghrelin and its functional receptor, the type 1a GHS-R, in adult human testis. In addition, evaluation of ghrelin and GHS-R1a immunoreactivity in testicular tumors and dysgenetic tissue is presented. The expression of the mRNAs encoding ghrelin and GHS-R1a was demonstrated in human testis specimens by RT-PCR, followed by direct sequencing. In normal testis, ghrelin immunostaining was demonstrated in interstitial Leydig cells and, at lower intensity, in Sertoli cells within the seminiferous tubules. In contrast, ghrelin was not detected in germ cells at any stage of spermatogenesis. The cognate ghrelin receptor showed a wider pattern of cellular distribution, with detectable GHS-R1a protein in germ cells, mainly in pachytene spermatocytes, as well as in somatic Sertoli and Leydig cells. Ghrelin immunoreactivity was absent in poorly differentiated Leydig cell tumor, which retained the expression of GHS-R1a peptide. In contrast, highly differentiated Leydig cell tumors expressed both the ligand and the receptor. The expression of ghrelin and GHS-R1a was also detected in dysgenetic Sertoli cell-only seminiferous tubules, whereas germ cell tumors (seminoma and embryonal carcinoma) were negative for ghrelin and were weakly positive for GHS-R1a. In conclusion, our results demonstrate that ghrelin and the type 1a GHS-R are expressed in adult human testis and testicular tumors. Overall, the expression of ghrelin and its functional receptor in human and rat testis, with roughly similar patterns of cellular distribution, is highly suggestive of a conserved role for this newly discovered molecule in the regulation of mammalian testicular function. Publisher: The Endocrine Society Relation: Gaytan, Felice and Barreiro, M. Luz and Caminos, Jorge Eduardo and Chopin, Lisa K. and Herington, Adrian C. and Morales, Concepcion and Paniagua, Ricardo and Nistal, Manuel and Casanueva, Felipe F. and Aguilar, Enrique and Dieguez, Carlos and Tena-Sempere, Manuel and Pinilla, Leonor (2004) Expression of Ghrelin and Its Functional Receptor, the Type 1a Growth Hormone Secretagogue Receptor, in Normal Human Testis and Testicular Tumors. The Journal of Clinical Endocrinology & Metabolism, 89(1). pp. 400-409. Rights: Copyright 2004 The Endocrine Society

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