A chitin-like component in Aedes aegypti eggshells, eggs and ovaries

An insoluble white substance was prepared from extracts of eggshells of Aedes aegypti, the yellow fever mosquito and dengue vector. Its infrared and proton NMR spectra were similar to that of standard commercial chitin. This putative chitin-like material, also obtained from ovaries, newly laid and dark eggs, was hydrolyzed in acid and a major product was identified by HPLC to be glucosamine. The eggshell acid hydrolysate was also analyzed by ESI-MS and an ion identical to a glucosamine monoprotonated species was detected. The presence of chitin was also analyzed during different developmental stages of the ovary using a fluorescent microscopy technique and probes specific for chitin. The results showed that a chitin-like material accumulates in oocytes during oogenesis. Streptomyces griseus chitinase pre-treatment of oocytes greatly reduced the chitin-derived fluorescence. Chitinase activity was detected in newborn larvae and eggs prior to hatching. Feeding experiments indicated that the chitin synthesis inhibitor lufenuron inhibited chitin synthesis, either when mosquitoes were allowed to feed directly on lufenuron-treated chickens or when an artificial feeding system was used. Lufenuron inhibited egg hatch, larval development and reduced mosquito viability. These data demonstrate for the first time that (1) a chitin-like material is present in A. aegypti eggs, ovaries and eggshells; (2) a chitin synthesis inhibitor can be used to inhibit mosquito oogenesis; and (3) chitin synthesis inhibitors have potential for controlling mosquito populations.     

Bayes factor for testing between different structures of random genetic groups: A case study using weaning weight in Bruna dels Pirineus beef cattle

The implementation of genetic groups in BLUP evaluations accounts for different expectations of breeding values in base animals. Notwithstanding, many feasible structures of genetic groups exist and there are no analytical tools described to compare them easily. In this sense, the recent development of a simple and stable procedure to calculate the Bayes factor between nested competing models allowed us to develop a new approach of that method focused on compared models with different structures of random genetic groups. The procedure is based on a reparameterization of the model in terms of intraclass correlation of genetic groups. The Bayes factor can be easily calculated from the output of a Markov chain Monte Carlo sampling by averaging conditional densities at the null intraclass correlation. It compares two nested models, a model with a given structure of genetic groups against a model without genetic groups. The calculation of the Bayes factor between different structures of genetic groups can be quickly and easily obtained from the Bayes factor between the nested models. We applied this approach to a weaning weight data set of the Bruna dels Pirineus beef cattle, comparing several structures of genetic groups, and the final results showed that the preferable structure was an only group for unknown dams and different groups for unknown sires for each year of calving.     

The effect of four fruit species on the parasitization rate of Anastrepha fraterculus (Diptera: Tephritidae,Trypetinae) by Diachasmimorpha longicaudata (Hymenoptera: Braconidae,Opiinae) under laboratory rearing conditions

In the laboratory, the effect of host fruit species Citrus paradisi, C. aurantium, Prunus persica, and Psidium guajava on A. fraterculus parasitism by Diachasmimorpha longicaudata was studied. The number of ovipositor-probing events and the probing-time were documented to evaluate the role of fruit chemistry, and epicarp and mesocarp thickness, respectively. The relationship between the parasitization rate and fruit size in particular plant species was analyzed by applying a simple regression. Results showed that guava and peach yielded significantly more parasitoids than both Citrus spp. Probably, the parasitization rate of D. longicaudata on A. fraterculus would be influenced in part by chemical and physical factors from fruit species.     

Identification of sources of microbial pathogens on cantaloupe rinds from pre-harvest to post-harvest operations

Foodborne illness outbreaks involving cantaloupes have increased dramatically in the past 15 years in the United States and other countries. The need for the identification of the microbial sources that contaminate cantaloupe rinds has been raised by various investigators. This study was undertaken to identify the agricultural, industrial and human sources of microbial contamination from the pre- to post-harvest operations of cantaloupes grown at ten different farms in southern Texas. Results indicate that irrigation water contained a wide range of microorganisms that could cause human illness and were able to survive on the rind of cantaloupes before, at, and after harvesting. Fungi, total aerobic bacteria and total coliform bacteria were not completely eliminated by chlorinated water in the disinfection tanks of the six packinghouses under investigation. There were significant (P < 0.05) reductions on rind populations of fungi and total aerobic bacteria as well as drastic reductions in total coliform bacteria on the rinds after the disinfection and rinsing steps in all packing facilities. There was no evidence of the presence of Escherichia coli O157:H7 on packed cantaloupes across packinghouses. Less than a geometric mean of 1 c.f.u. cm⁻² of salmonellae were detected on the surface of packed cantaloupes in two of the packinghouses, and approximately ten times more salmonellae were found on the packed fruit processed in the remaining packinghouses. A similar trend was observed with listeriae. Results suggested that microbial loads originating from river water may survive on the rind or may re-infest cantaloupes after the disinfection and rinsing process at the packinghouses. Disinfection techniques and aseptic handling of cantaloupes at the packing facilities need a closer evaluation to ensure a safe product.     

Linking bioprospecting with sustainable development and conservation: the Panama case

The limited international resources for economic aid and conservation can only mitigate poverty and losses of biodiversity. Hence, developing nations must establish the capacity to resolve their problems. Additionally, policy-makers and donors need to obtain scientific input on issues such as global change and ecosystem services. We propose that for nations rich in biodiversity, ecosystem services derived from bioprospecting, or drug discovery, could contribute to economic development. In the case where unstudied samples are shipped abroad for research, the chances of obtaining royalties are infinitesimally small. Therefore developing nations will only realize benefits from bioprospecting through in-country research on their own biodiversity. Policy-makers and donors have failed to appreciate the value of this approach. In order to provide an example of the inherent links between conservation and sustainable economic development, we initiated a drug discovery effort in Panama that emphasizes local benefit. As much of the drug discovery process as possible is conducted in Panamanian laboratories, providing jobs dependent on intact biodiversity and enhancing local research and training. In short, research, plus the spin-offs from research, provide immediate and long-lasting benefits to Panama. The connection between conservation and development has been highlighted in publicity about the project in Panama’s urban media. This provides a constructive alternative to the perception the among the urban populace that economic development inevitably competes with conservation. In summary, our program uses biodiversity to promote human health as well as to support research capacity, economic development and conservation within Panama. The program provides an example of the widely recognized but little developed concept of bioprospecting research as an ecosystem service.     

Are important bird areas and special protected areas enough for conservation?: the case of Bonelli’s eagle in a Mediterranean area

The Bonelli’s eagle (BE) is considered by the European Union as a high-priority species for conservation in the Valencian Community (East of Spain). However, in 2006 the European Union opened a legal procedure against the Spanish Kingdom, accused of lacking of an adequate network of special protected areas (SPAs) to preserve the BE in the region. Here we evaluate whether important bird areas (IBAs) and SPAs network is enough to preserve this species, on the basis of a thorough analysis of habitat preferences. A GAP analysis is performed to conduct a revision of current SPAs and BirdLife proposed IBAs. Our results suggest that the current network of SPAs becomes insufficient to protect the BE. The IBAs network, although improves the current network of SPAs, increasing the percentage of BE potential habitat included, also results inadequate. We propose a new SPAs network according to the potential suitable habitat for the species. Given the trade-off between financial investment and the conservation of biodiversity, we propose to maximize the surface of potential habitat included in the protected network minimizing the surface of the region that would be necessary to protect, thus avoiding an unnecessary expense and otherwise unrealistic results.     

Synthesis of two carboxylic haptens for raising antibodies to 25-hydroxyvitamin D3 and 1alpha,25-dihydroxyvitamin D3

Hapten derivatives of 25-hydroxyvitamin D(3) and 1alpha,25-dihydroxyvitamin D(3) were synthesized using the Wittig-Horner approach. Both haptens bearing a carboxylic group at the side chain that can be linked to a protein for raising antibodies of potential utility for the determination of 25-hydroxyvitamin D(3), 1alpha,25-dihydroxyvitamin D(3) and 1alpha-hydroxylated vitamin D(3) analogues.     

Modelling habitat use and distribution of golden eagles <Emphasis Type="Italic">Aquila chrysaetos</Emphasis> in a low-density area of the Iberian Peninsula

We analyse the current situation of the Golden eagle (Aquila chrysaetos) in the region of Galicia in NW Spain. At present, the entire Galician population (five pairs) is located within an area of about 2000 km² in the province of Ourense. To identify high-priority areas for golden eagle conservation, we derived predictive models of habitat suitability using logistic regression and a Geographic Information System (GIS). Specifically, to model the distribution of the breeding population we considered topographic features, land use and degree of humanization, using a 10 × 10 km grid. Presence/absence of golden eagle nests was used as the dependent variable; analyses were performed both considering current nesting areas and considering old nesting areas (1960s and 70s). At the spatial scale considered, the best predictors of habitat suitability for breeding were topographical variables indicative of rugged relief. For current nesting areas the most parsimonious model included maximum altitude. We consider that the predictive models obtained may be of use for the monitoring and conservation management of the golden eagle population in this region. Conservation problems associated with habitat constraints such as food supply, availability of nesting sites, changes in land use and human disturbance are discussed.