Mariculture and Natural Production of the Antitumoural (+)-Discodermolide by the Caribbean Marine Sponge Discodermia dissoluta

Biotechnological research on marine organisms, such as ex situ or in situ aquaculture and in vitro cell culture, is being conducted to produce bioactive metabolites for biomedical and industrial uses. The Caribbean marine sponge Discodermia dissoluta is the source of (+)-discodermolide, a potent antitumoural polyketide that has reached clinical trials. This sponge usually lives at depths greater than 30 m, but at Santa Marta (Colombia) there is a shallower population, which has made it logistically possible to investigate for the first time, on ways to supply discodermolide. We thus performed in situ, 6-month fragment culture trials to assess the performance of this sponge in terms of growth and additional discodermolide production and studied possible factors that influence the variability of discodermolide concentrations in the wild. Sponge fragments cultured in soft mesh bags suspended from horizontal lines showed high survivorship (93 %), moderate growth (28 % increase in volume) and an overall rise (33 %) in the discodermolide concentration, equivalent to average additional production of 8 μg of compound per millilitre of sponge. The concentration of discodermolide in wild sponges ranged from 8 to 40 μg mL^?1. Locality was the only factor related to discodermolide variation in the wild, and there were greater concentrations in peripheral vs. basal portions of the sponge, and in clean vs. fouled individuals. As natural growth and regeneration rates can be higher than culture growth rates, there is room for improving techniques to sustainably produce discodermolide.     

Generalist Species Have a Central Role In a Highly Diverse Plant–Frugivore Network

Analysis of plant–frugivore interactions provides a quantitative framework for integrating community structure and ecosystem function in terms of how the roles and attributes of individual species contribute to network structure and resilience. In this study, we used centrality metrics to rank and detect the most important species in a mutualistic network of fruit‐eating birds and plants in a cloud forest in the Colombian Andes. We identified a central core of ten bird and seven plant species in a network of 135 species that perform dual roles as local hubs and connectors. The birds were mostly large forest frugivores, such as cracids, cotingas, and toucans, which consume fruits of all sizes. The plants were species of intermediate successional stages with small‐ to medium‐sized seeds that persist in mature forest or forest borders (e.g., Miconia, Cecropia, Ficus). We found the resilience of our network depends on super‐generalist species, because their elimination makes the network more prone to disassemble than random extinctions, potentially disrupting seed‐dispersal processes. At our study site, extirpation of large frugivores has already been documented, and if this continues, the network might collapse despite its high diversity. Our results suggest that generalist species play critical roles in ecosystem function and should be incorporated into conservation and monitoring programs.     

Neurological effects of American trypanosomyiasis: clinical aspects

Trypanosoma cruzi, causative agent of Chagas disease, affects not only cardiac and intestinal structures but also neurological structures. A high prevalence of T. cruzi infection occurs in Colombia, prompting the present study. First, a qualitative metaanalysis was undertaken using the PubMed database, the electronic internet engine Altavista, Colombian journals indexed by Colciencias, and three relevant textbooks. The following key words were used: Trypanosoma, Chagas disease, nervous system, spinal cord, central nervous system, peripheral nervous system, neuromuscular junction, autonomic nervous system, muscle, muscle disorders, neuromuscular disease, neuromuscular disorders, synapticopathies and dysautonomia. The documents analyzed numbered 116 and included original papers, reviews, case reports, editorials, brief communications, conferences and book chapters. At minimum, each document included data involving ELISA testing, indirect immunofluorescense, or parasitemia levels in the clinical, serological or histopathological studies. Polymerase chain reaction (PCR) studies were not included because of the recent introduction of PCR as a confirmatory technique for Chagas disease in Colombia. Chagas disease affects the central, the peripheral and the autonomic nervous system in humans, although its effects on the antonomic system is most commonly investigated in Colombia. Neurological lesions must be evaluated carefully, because patients may be misdiagnosed and treated as carriers of 'idiopathic' diseases. Neurological pathologies poses a serious threat in Colombia due to the prevalence of Chagas disease.     

Distribution of flavonoids in the Myristicaceae

During the past two decades the study of the Myristicaceae species has increased, and many flavonoids of different types have been isolated. This review discusses the flavonoids presently known in the Myristicaceae.     

Differential detection of Debaryomyces hansenii isolated from intermediate-moisture foods by PCR-RFLP of the IGS region of rDNA

The amplification by PCR of the Intergenic Spacer region (IGS) of rDNA followed by Restriction Fragment Length Polymorphism (RFLP) analysis was evaluated as a potential method for the identification of Debaryomyces hansenii among other yeast species that frequently contaminate Intermediate-Moisture Foods (IMFs). For a first rapid differentiation at the species level, the determination of the IGS-PCR fragment size was found to be a useful approach. The digestion of this region with the enzymes HhaI, HapII and MboI resulted in specific patterns that permit the identification of D. hansenii among other yeast species. This method also permitted the discrimination between the D. hansenii varieties (var. hansenii and var. fabryi) as well as the differentiation of D. hansenii from other species of the genus, such as Debaryomyces pseudopolymorphus or Debaryomyces polymorphus var. polymorphus. The IGS-PCR RFLP method was assayed for the differential detection of D. hansenii in contaminated or spoiled IMF products and compared with traditional identification procedures, resulting in a 100% detection rate for D. hansenii.