Presence of Alkaloids and Cyanogenic Glycosides in Fruits Consumed by Sympatric Bonobos and the Nkundo People at LuiKotale/Salonga National Park, Democratic Republic of Congo and Its Relationship to Food Choice

The importance of secondary compounds remains poorly studied in wild plants eaten by bonobos (Pan paniscus) and humans. As part of this study, alkaloids and cyanogenic glycosides (cyanide) were investigated in wild fruits consumed by bonobos at LuiKotale in Salonga National Park. In high concentrations, the two components can become toxic. Therefore, we investigated whether the bonobos and the Nkundo people avoid high concentrations of these components in their food. To analyze alkaloids and to detect the presence of cyanogenic glycosides, we used semi-quantitative methods. Of the 75 species of fruit analyzed, 28 species (37%) were revealed to have alkaloids at different proportions and 47 species (63%) were shown to be without alkaloids, 12 species (16%) with low concentrations (+), 14 species (19%) with moderate concentrations (++), and two species (3%) with high concentrations (+++). Of the 75 species, 60 were eaten, of which 46 were consumed only by bonobos, 13 were eaten by both bonobos and the Nkundo people, and one species (Piper guinensis) was eaten only by the Nkundo people. In total, bonobos ate 59 species and the Nkundo people 14 species. Of the 60 species consumed, the majority, i.e., 39 species (65%) did not show the presence of alkaloids, while 11 species (18%) showed a low concentration and 10 species (17%) moderate concentrations. As for cyanogenic glycosides (cyanide), this was detected in only three of the 75 species of fruit analyzed. Two species, Camptostylus mannii and Dasylepsis seretii, belong to the Achariaceae family, with Oncoba welwitschii in the Salicaceae family. The two species of Achariaceae both contain alkaloids and cyanogenic glycosides. No species eaten by the Nkundo contained cyanogenic glycosides. Hence, we infer that bonobos and the Nkundo people both avoid eating fruit species that contain high concentrations of alkaloids and cyanogenic glycosides, and this might have relevance linked to the evolution of seed dispersal

SCI1 Is a Direct Target of AGAMOUS and WUSCHEL and Is Specifically Expressed in the Floral Meristematic Cells

The specified floral meristem will develop a pre-established number of floral organs and, thus, terminate the floral meristematic cells. The floral meristematic pool of cells is controlled, among some others, by WUSCHEL (WUS) and AGAMOUS (AG) transcription factors (TFs). Here, we demonstrate that the SCI1 (Stigma/style cell-cycle inhibitor 1) gene, a cell proliferation regulator, starts to be expressed since the floral meristem specification of Nicotiana tabacum and is expressed in all floral meristematic cells. Its expression is higher in the floral meristem and the organs being specified, and then it decreases from outside to inside whorls when the organs are differentiating. SCI1 is co-expressed with N. tabacum WUSCHEL (NtWUS) in the floral meristem and the whorl primordia at very early developmental stages. Later in development, SCI1 is co-expressed with NAG1 (N. tabacum AG) in the floral meristem and specialized tissues of the pistil. In silico analyses identified cis-regulatory elements for these TFs in the SCI1 genomic sequence. Yeast one-hybrid and electrophoresis mobility shift assay demonstrated that both TFs interact with the SCI1 promoter sequence. Additionally, the luciferase activity assay showed that NAG1 clearly activates SCI1 expression, while NtWUS could not do so. Taken together, our results suggest that during floral development, the spatiotemporal regulation of SCI1 by NtWUS and NAG1 may result in the maintenance or termination of proliferative cells in the floral meristem, respectively

The Bi-Loop, a new general four-stranded DNA motif

The crystal structure of the cyclic octanucleotide d contains two independent molecules that form a novel quadruplex by means of intermolecular Watson-Crick A.T pairs and base stacking. A virtually identical quadruplex composed of G.C pairs was found by earlier x-ray analysis of the linear heptamer d(GCATGCT), when the DNA was looped in the crystal. The close correspondence between these two structures of markedly dissimilar oligonucleotides suggests that they are both examples of a previously unrecognized motif. Their nucleotide sequences have little in common except for two separated 5'-purine-pyrimidine dinucleotides forming the quadruplex, and by implication these so-called 'bi-loops' could occur widely in natural DNA. Such structures provide a mechanism for noncovalent linking of polynucleotides in vivo. Their capacity to associate by base stacking, demonstrated in the crystal structure of d(GCATGCT), creates a compact molecular framework made up of four DNA chains within which strand exchange could take place

Molecular phylogeny and timing of diversification in Alpine Rhithrogena (Ephemeroptera: Heptageniidae).

BACKGROUND: Larvae of the Holarctic mayfly genus Rhithrogena Eaton, 1881 (Ephemeroptera, Heptageniidae) are a diverse and abundant member of stream and river communities and are routinely used as bio-indicators of water quality. Rhithrogena is well diversified in the European Alps, with a number of locally endemic species, and several cryptic species have been recently detected. While several informal species groups are morphologically well defined, a lack of reliable characters for species identification considerably hampers their study. Their relationships, origin, timing of speciation and mechanisms promoting their diversification in the Alps are unknown. RESULTS: Here we present a species-level phylogeny of Rhithrogena in Europe using two mitochondrial and three nuclear gene regions. To improve sampling in a genus with many cryptic species, individuals were selected for analysis according to a recent DNA-based taxonomy rather than traditional nomenclature. A coalescent-based species tree and a reconstruction based on a supermatrix approach supported five of the species groups as monophyletic. A molecular clock, mapped on the most resolved phylogeny and calibrated using published mitochondrial evolution rates for insects, suggested an origin of Alpine Rhithrogena in the Oligocene/Miocene boundary. A diversification analysis that included simulation of missing species indicated a constant speciation rate over time, rather than any pronounced periods of rapid speciation. Ancestral state reconstructions provided evidence for downstream diversification in at least two species groups. CONCLUSIONS: Our species-level analyses of five gene regions provide clearer definitions of species groups within European Rhithrogena. A constant speciation rate over time suggests that the paleoclimatic fluctuations, including the Pleistocene glaciations, did not significantly influence the tempo of diversification of Alpine species. A downstream diversification trend in the hybrida and alpestris species groups supports a previously proposed headwater origin hypothesis for aquatic insects