Learning by doing: a participatory methodology for systematization of experiments with agroforestry systems, with an example of its application

Participatory research methods have helped scientists to understand how farmers experiment and to seek partnerships with farmers in developing technologies with enhanced relevance and adoption. This paper reports on the development of a participatory methodology to systematize long-term experimentation with agroforestry systems carried out in a hotspot of biodiversity by non-governmental organizations and local farmers. A methodological guide for systematization and techniques used for Participatory Rural Appraisal formed the basis of our work. We propose an analytical framework that recognizes systems of reflexive and learning interactions, in order to make the learned lessons explicit. At the process level, the main lessons and recommendations are as follows. It is important to establish partnerships to conduct innovative and complex experimentation with agroforest. Participatory systematization allows us to improve the methodological aspects of design, implementation and management of on-farm participatory experimentation. It also serves to synthesize the main findings and to extract lessons from agroforestry systems experiments. It fosters the technical improvement of agroforestry systems. It creates possibilities for reflection on agroforestry systems by farmers, extensionists and researchers, as well as their learning with respect to management of such systems. The findings are placed in the context of current theory on participatory experimentation in agriculture. Extractive and interactive approaches help to produce rich insights of mutual interest through collaboration by identifying local, regional and global convergences, complementarities, and conflicts of interest; which affect the advance of new eco-friendly technologies, to both improve the livelihoods and to reverse biodiversity loss and environmental degradation.     

Subolesin/akirin orthologs from Ornithodoros spp. soft ticks: cloning, RNAi gene silencing and protective effect of the recombinant proteins

Subolesin/akirin is a well characterized protective antigen highly conserved across vector species and thus potentially useful for the development of a broad-spectrum vaccine for the control of arthropod infestations including hard ticks, mosquitoes, sand flies and the poultry red mite Dermanyssus gallinae. Soft ticks could be also targeted by this vaccine if proved that the soft tick subolesin orthologs are conserved and induce protective immune responses too. However, to date no soft tick subolesin orthologs have been fully characterized nor tested as recombinant antigens in vaccination trials. The objectives of the present work were to clone and characterize the subolesin orthologs from two important vector species of soft ticks as Ornithodoros erraticus and O. moubata, to evaluate the effect of subolesin gene silencing by RNAi, and to test the protective value of the recombinant antigens in vaccination trials. The obtained results demonstrate that both soft tick subolesins are highly conserved showing more than 69% and 74% identity with those of hard ticks in their nucleotide and amino acid sequences, respectively. Additionally, we demonstrate that both soft ticks possess fully operative RNAi machinery, and that subolesin gene silencing by dsRNA injection inhibits oviposition indicating the involvement of subolesin in tick reproduction. Finally, vaccination with the recombinant soft tick subolesins induced a partial protective effect resulting in the reduction of the oviposition rate. These preliminary results encourage further studies on the use of recombinant subolesins as vaccines for the control of soft tick infestations, either alone or in combination with other specific molecules.     

Dual-label time-resolved fluoroimmunoassay for simultaneous quantification of haptoglobin and C-reactive protein in meat juice from pigs

A new method was developed to simultaneously measure 2 acute-phase proteins (APPs) by time-resolved immunofluorometry. The assay, based on double-label quantification of haptoglobin (Hp) and C-reactive protein (CRP) in meat juice samples from pigs, was constructed by use of a combination of europium and samarium chelate lanthanides as labels. Meat juice samples from 154 pigs were used for analytic and clinical validation of the assay through determination of precision, accuracy, limit of detection, and quantification. The analytic performance of the assay was satisfactory, with good intra-assay and interassay precision and accuracy. The levels of Hp and CRP were increased in the meat juice samples of diseased animals compared with healthy ones. According to the results, higher sensitivity could be achieved if the cut-off values of both proteins were taken into account for clinical relevance rather than used individually. Since the dual assay saved both time and sample, it could be used as a rapid and sensitive screening test in porcine production.     

Sertoli cell tumors associated with feminizing syndrome and spermatic cord torsion in two cryptorchid dogs

The association of cryptorchidism, functional Sertoli cell tumors, and spermatic cord torsion has been rarely reported in the literature. Two dogs were admitted for bilateral skin alopecia and weight loss. Both animals were cryptorchid and displayed a pendulous preputial sheath, prostate hypertrophy, and increased levels of circulating oestrogen. Transabdominal palpation and ultrasonography revealed the presence of neoplastic retained gonads. During surgery, spermatic cord torsion was also detected in the enlarged neoplastic testes of both dogs. Histologic examination confirmed the presence of Sertoli cell tumors that were primarily responsible for the feminizing syndrome. Complete remission of all symptoms occurred within 3 months after orchiectomy.     

Ectomycorrhizal inoculation with Pisolithus tinctorius increases the performance of Quercus suber L. (cork oak) nursery and field seedlings

Mediterranean ecosystems are characterized by large arid areas where the patchy distribution of trees offers little protection against harsh climate conditions for seedling establishment. Climate change is predicted to result in an increase in these arid regions, with pronounced effects on vegetation. Production of seedlings with developed ectomycorrhizas is a promising strategy for minimizing the initial transplant shock, thereby increasing plant survival and growth during the first, most critical years of a plantation. One important species in the Mediterranean basin is Quercus suber (cork oak), which occurs, together with other evergreen oak species, in an agro-silvo-pastoral system that represents an example of sustainable land use in Europe. In this study, a Pisolithus tinctorius isolate was used for ectomycorrhizal colonization of cork oak nursery seedlings, and the effects on aboveground plant growth and leaf structural and physiological parameters were investigated. Ectomycorrhizal development resulted in a significant increase in leaf area, dry weight, nitrogen content, and photosynthetic pigments, and mycorrhizal plants showed a higher photosynthetic capacity and water use efficiency. Nursery-inoculated plants established in the field showed increased survival and growth during the first year after transplant. These results indicate a potential for further enhancing the use of mycorrhizal inoculation as a cultivation practice in forest nurseries. Considering the difficulty of soil restoration under limiting environmental conditions, nursery inoculation with ectomycorrhizal fungi can be an important advantage for improving the quality of seedling stock and its performance after out-planting in the field, benefiting the regeneration of arid regions and the reintroduction of inocula of ectomycorrhizal fungi into these areas.     

Natural durability of wood of ten native species from northeastern Mexico

Thorn scrub vegetation in Mexico is distributed over 50 million ha, where native tree species are the source of forage, timber, firewood and charcoal. Research describing wood durability of species from this vegetation type has not been fully determined, nor classified according to international standards. Thus, the aim of this study was to determine and classify the natural durability of ten woody species. Their natural durability was determined according to the European Pre-Norm 807, the loss of dynamic modulus of elasticity (MOEdyn) (MPa) was determined and wood mass loss (g) after being exposed to Trametes versicolor and Coniophora puteana fungi. Wood durability was classified according to the European Norm 350-1. Highly significant differences (p<0.001) were found between the durability of woody species. The more durable species with lower MOEdyn lost were Condalia hookeri (57.5%±0.6%), Havardia pallens (58.2%±0.4%) and Acacia schaffneri (58.9%±6.3%). Species with lower mass loss after exposed to Coniophora puteana were Ebenopsis ebano (6.3%±1.9%), Condalia hookeri (8.6%±2.3%) and Cordia boissieri (11.8%±2.3%). E. ebano (7.1%±2.4%), Condalia hookeri (8.2%±2.5%) and Cordia boissieri (11.5%±3.1%) showed the lower mass lost after exposed to T. versicolor. According to European Norm 350-1, three woody species were classified as very durable and durable species.     

Gastrointestinal parasites in greater rheas (Rhea americana) and lesser rheas (Rhea pennata) from Argentina

Few data exist on the parasites of ratites, especially from regions within their natural range. It is only recently that extensive studies on the parasites of ostriches (Struthio camelus) have been published, mainly from European countries where commercial farming has expanded. Two species of ratites are native in South America: the lesser rhea also known as Darwin's rhea (Rhea pennata) and the greater rhea (Rhea americana). Both species are considered near threatened by the IUCN and are included in the CITES’ Appendices I and II, respectively. Parasitological studies have conservation implications, as they allow us to assess the risk of transmission of pathogens from farmed ratites to wild populations. In this study 92 faecal samples from greater rheas and 55 faecal samples from lesser rheas from different localities in Argentine were analyzed to determine their gastrointestinal parasites. In greater rheas the protozoa (Balantidium coli-like and Entamoeba spp.) and helminths (Fasciola hepatica and Deletrocephalus spp.). The protozoa had not previously been cited as parasites of greater rheas in South America. Cysts and/or trophozoites of B. coli-like were found in 16.3% of the samples, while the prevalence of the remaining parasites was below 10%. Lesser rheas harbored the protozoa B. coli-like, Entamoeba spp. and Chilomastix spp. as well as F. hepatica and nematode eggs and larvae. B. coli-like cysts were found in 20.0% of the samples, while the prevalence of the other parasites remained below 5%. Some of them had not been cited as infecting lesser rheas yet.     

Fatty Acid Profile,Total Carotenoids,and Free Radical-Scavenging from the Lipophilic Fractions of 12 Native Mexican Avocado Accessions

Plant Foods for Human Nutrition - Mexico is the world’s largest producer, exporter, and consumer of avocados. “Hass” avocado is the most commercialized cultivar, while the native...     

Usefulness of rNcGRA7- and rNcSAG4-based ELISA tests for distinguishing primo-infection, recrudescence, and chronic bovine neosporosis

Bovine reproductive failure caused by the parasite Neospora caninum is a major problem and is responsible for severe economic losses worldwide. Currently, appropriate control measures depend on the predominant transmission route in a particular herd. Therefore, the development of diagnostic tools capable of discriminating between primo-infection, recrudescence, re-infection, and chronic infection is a major challenge in the serodiagnosis of bovine neosporosis. Here, two recombinant protein-based ELISAs utilizing the immunodominant NcGRA7 dense granule protein and the NcSAG4 bradyzoite stage-specific protein were developed and showed good diagnostic performances. Their usefulness for discerning between primo-infection, recrudescence, re-infection, and chronic infection was also studied by analyzing an appropriate panel of serum samples belonging to different groups of experimentally and naturally infected bovines. Our results suggest that anti-rNcGRA7 antibody levels may be indicative of acute infection (primo-infection, re-infection, and recrudescence), whereas the presence of anti-rNcSAG4 antibodies may be associated with chronic infection and could be a good indicator of infection establishment (tachyzoite-bradyzoite conversion). Moreover, primo-infection associated with a Neospora-associated epidemic abortion pattern is characterized by the detection of anti-rNcGRA7 antibodies together with the absence or detection of anti-rNcSAG4 antibody levels around the cut-off point. In contrast, the detection of antibody levels directed against both recombinant proteins may be quite indicative of recrudescence or re-infection associated with abortion and/or vertical transmission in herds with a Neospora-associated endemic abortion pattern. In conclusion, both serological tests developed in the present study offer additional information to conventional avidity tests and, consequently, improve the diagnosis of bovine neosporosis with perspectives for control measures.