Morphological variation,management and domestication of ‘maguey alto’ (<Emphasis Type="Italic">Agave inaequidens</Emphasis>) and ‘maguey manso’ (<Emphasis Type="Italic">A. hookeri</Emphasis>) in Michoacán,México

Background

Agave inaequidens and A. hookeri are anciently used species for producing the fermented beverage ‘pulque’, food and fiber in central Mexico. A. inaequidens is wild and cultivated and A. hookeri only cultivated, A. inaequidens being its putative wild relative. We analysed purposes and mechanisms of artificial selection and phenotypic divergences between wild and managed populations of A. inaequidens and between them and A. hookeri, hypothesizing phenotypic divergence between wild and domesticated populations of A. inaequidens in characters associated to domestication, and that A. hookeri would be phenotypically similar to cultivated A. inaequidens.

Methods

We studied five wild and five cultivated populations of A. inaequidens, and three cultivated populations of A. hookeri. We interviewed agave managers documenting mechanisms of artificial selection, and measured 25 morphological characters. Morphological similarity and differentiation among plants and populations were analysed through multivariate methods and ANOVAs.

Results

People recognized 2–8 variants of A. inaequidens; for cultivation they select young plants collected in wild areas recognized as producing the best quality mescal agaves. Also, they collect seeds of the largest and most vigorous plants, sowing seeds in plant beds and then transplanting the most vigorous plantlets into plantations. Multivariate methods classified separately the wild and cultivated populations of A. inaequidens and these from A. hookeri, mainly because of characters related with plant and teeth size. The cultivated plants of A. inaequidens are significantly bigger with larger teeth than wild plants. A. hookeri are also significatly bigger plants with larger leaves but lower teeth density and size than A. inaequidens. Some cultivated plants of A. inaequidens were classified as A. hookeri, and nearly 10% of A. hookeri as cultivated A. inaequidens. Wild and cultivated populations of A. inaequidens differed in 13 characters, whereas A. hookeri differed in 23 characters with wild populations and only in 6 characters with cultivated populations of A. inaequidens.

Conclusions

Divergence between wild and cultivated populations of A. inaequidens reflect artificial selection. A. hookeri is similar to the cultivated A. inaequidens, which supports the hypothesis that A. hookeri could be the extreme of a domestication gradient of a species complex.

     

Phyllostomid Bat Occurrence in Successional Stages of Neotropical Dry Forests

Tropical dry forests (TDFs) are highly endangered tropical ecosystems being replaced by a complex mosaic of patches of different successional stages, agricultural fields and pasturelands. In this context, it is urgent to understand how taxa playing critical ecosystem roles respond to habitat modification. Because Phyllostomid bats provide important ecosystem services (e.g. facilitate gene flow among plant populations and promote forest regeneration), in this study we aimed to identify potential patterns on their response to TDF transformation in sites representing four different successional stages (initial, early, intermediate and late) in three Neotropical regions: México, Venezuela and Brazil. We evaluated bat occurrence at the species, ensemble (abundance) and assemblage level (species richness and composition, guild composition). We also evaluated how bat occurrence was modulated by the marked seasonality of TDFs. In general, we found high seasonal and regional specificities in phyllostomid occurrence, driven by specificities at species and guild levels. For example, highest frugivore abundance occurred in the early stage of the moistest TDF, while highest nectarivore abundance occurred in the same stage of the driest TDF. The high regional specificity of phyllostomid responses could arise from: (1) the distinctive environmental conditions of each region, (2) the specific behavior and ecological requirements of the regional bat species, (3) the composition, structure and phenological patterns of plant assemblages in the different stages, and (4) the regional landscape composition and configuration. We conclude that, in tropical seasonal environments, it is imperative to perform long-term studies considering seasonal variations in environmental conditions and plant phenology, as well as the role of landscape attributes. This approach will allow us to identify potential patterns in bat responses to habitat modification, which constitute an invaluable tool for not only bat biodiversity conservation but also for the conservation of the key ecological processes they provide.     

Community-Based Ecotourism and Primate Watching as a Conservation Tool in the Amazon Rainforest

International Journal of Primatology - Community-based tourism is a participatory approach implemented to support the economic and social development of local communities. Here, we present the...     

Prenatally diagnosed foetal malformations and termination of pregnancy: the case of Lebanon

Termination of pregnancy (TOP) is offered in many countries, for foetuses prenatally diagnosed with congenital malformations that are deemed incompatible with life or that are associated with a high morbidity. In Lebanon, a middle income country where religion plays a focal role, the law prohibits any form of TOP unless it is the only means to save the mother's life. It is the contention of the authors of this article that even if the foetus is a person, if it were medically revealed that there is a substantial risk that the newborn will suffer severe physical abnormalities that will cause it to be seriously handicapped; it is morally acceptable to terminate the pregnancy. Hence, TOP carried out for these indications is justified in the interest of the foetus and the child. Whatever the status of the foetus is, once born, it will become a full-fledged sentient being with all that this entails. When given the option of starting an existence, this person-to-be has the right to a minimum that allows him/her to enjoy a relatively good quality of life. Today, Lebanese obstetricians are confronted with the burden placed on them under the law to refuse TOP, or, when performing them, to forge records or deny having done them. This is why we strongly believe that the Lebanese policy on abortion should be amended.     

Antiangiogenic properties of Koetjapic acid, a natural triterpene isolated from Sandoricum koetjaoe Merr

Background

Angiogenesis, the formation of new blood vessels, has become an important target in cancer therapy. Angiogenesis plays an important role in tumor growth and metastasis. Koetjapic acid (KA) is a seco-A-ring oleanene triterpene isolated from S. koetjape. The solvent extract of this plant species was shown previously to have strong antiangiogenic activity; however the active ingredient(s) that conferred the biological activity and the mode of action was not established. Given the high concentration of KA in S. koetjape, an attempt has been made in this study to investigate the antiangiogenic properties of KA.

Results

Treatment with 10-50 μg/ml KA resulted in dose dependent inhibition of new blood vessels growth in ex vivo rat aortic ring assay. KA was found to be non-cytotoxic against HUVECs with IC₅₀ 40.97 ± 0.37 μg/ml. KA inhibited major angiogenesis process steps, endothelial cell migration and differentiation as well as VEGF expression.

Conclusions

The non-cytotoxic compound, KA, may be a potent antiangiogenic agent; its activity may be attributed to inhibition of endothelial cells migration and differentiation as well VEGF suppression.     

Genetic diversity of root anatomy in wild and cultivated Manihot species

An anatomical study of roots was conducted on two wild Manihot species, namely M. glaziovii and M. fortalezensis, and two cassava varieties, M. esculenta Crantz variety UnB 201 and M. esculenta variety UnB 122, to identify taxonomic differences in primary growth. Anatomical characters of cassava roots have been rarely investigated. Their study may help cassava breeders to identify varieties with economically important characters, such as tolerance to drought. We investigated tap and lateral adventitious roots of two specimens of each clone or species. Free-hand cross-sections of roots were drawn; these had been clarified with 20% sodium hypochlorite solution, stained with 1% safranin-alcian blue ethanolic solution, dehydrated in ethanol series and butyl acetate and mounted in synthetic resin. Anatomical differences among Manihot species and varieties were found in the epidermal and exodermal cell shape and wall thickness, content of cortical parenchyma, and number of xylem poles. Wall thickness of the epidermis and exodermis of tap root were similar in all species, while in the lateral root there were differences in cell shape and wall thickness. Epidermal cells with thick walls were found in the tap root of all species and in lateral roots of cassava varieties. This character is apparently associated with tolerance to drought and disease. The variation in the number of xylem poles of cassava varieties was larger (4-8) than in wild species (4-6), and appears to support the hybrid origin of cassava.     

An Eco-Friendly Synthesis of Some Novel Chromene-Based Heterocyclic Compounds of Biological Interest

Russian Journal of Bioorganic Chemistry - The target chromonylchalcone 3-(3-(4-oxo-4H-chromen-3-yl)-acryloyl)-2H-chromen-2-one was synthesized by reacting 3-acetylcoumarin with 3-formylchromone....     

Structure and Intrinsic Disorder in Protein Autoinhibition

1. Download : Download high-res image (184KB)
2. Download : Download full-size image

Highlights? Autoinhibitory regions in proteins are enriched in intrinsic disorder ? Modulation of intrinsic disorder contributes to the fine-tuning of autoinhibition ? Disordered autoinhibitory regions are more often phosphorylated and change structure ? Intrinsic disorder in inhibitory regions is exploited to fine-tune inhibition     

Apomixis in different ploidy levels of cassava

Two polyploid hybrids between cassava (Manihot esculenta) cultivar 307-2 and its wild relatives M. glaziovii and M. anomala, were studied to examine the relationship between ploidy level and the production of seeds without fertilization. A clearing method was applied to assess ovule sizes as an indication of multiembryony. The diploid cultivar 307-2 had regular 18 bivalents at meiotic metaphase 1 while the polyploid types showed chromosome configurations varying from 3 to 4 quadrivalents and 28 to 30 bivalents. A total of 14% of studied ovules of the polyploid hybrid involving M. glaziovii were multiebryonic, while the percentage of multiembryony was as low as 2% in the polyploid hybrid M. anomala×M. esculenta. Diploid hybrid types did not show any multi embryony. Adventitious embryos were found and documented for the first time in polyploid hybrids M. esculenta×M. glaziovii. The association of multiple embryo formation with ovary size and pollination showed that apomictic embryos form independently from fertilization. Simple iodized carmine stain for measuring pollen viability proved as efficient as the sophisticated Alexander method.