Fertilizing Methods and Nutrient Balance at the End of Traditional Organic Agriculture in the Mediterranean Bioregion: Catalonia (Spain) in the 1860s

By reconstructing the nutrient balance of a Catalan village circa 1861–65 we examine the sustainability of organic agricultural systems in the northwest Mediterranean bioregion prior to the green revolution and the question of whether the nutrients extracted from the soil were replenished. With a population density of 59 inhabitants per square km, similar to other northern European rural areas at that time, and a lower livestock density per cropland unit, this village experienced a manure shortage. The gap was filled by other labour-intensive ways of transferring nutrients from uncultivated areas into the cropland. Key elements in this agricultural system were vineyards because they have few nutrient requirements, and woodland and scrublands as sources of relevant amounts of nutrients collected in several ways.     

Effect of spent mushroom compost tea on mycelial growth and yield of button mushroom (Agaricus bisporus)

Preliminary studies suggested that the use of compost tea made from spent mushroom substrate (SMS) may be regarded as a potential method for biologically controlling dry bubble disease in button mushroom. The aim of this study was to assess the effect of SMS compost tea on the host, the button mushroom, to ascertain whether the addition of these water extracts has a toxic effect on Agaricus bisporus mycelium growth and on mushroom yield. In vitro experiments showed that the addition of SMS compost tea to the culture medium inoculated with a mushroom spawn grain did not have an inhibitory effect on A. bisporus mycelial growth. The effect of compost teas on the quantitative production parameters of A. bisporus (yield, unitary weight, biological efficiency and earliness) was tested in a cropping trial, applying the compost teas to the casing in three different drench applications. Quantitative production parameters were not significantly affected by the compost tea treatments although there was a slight delay of 0.8-1.4 days in the harvest time of the first flush. These results suggest that compost teas have no fungitoxic effect on A. bisporus so that they can be considered a suitable biocontrol substance for the control of dry bubble disease.     

Genetic diversity in commercial wineries: effects of the farming system and vinification management on wine yeasts

Aims: Analysis of the diversity and distribution of wine yeasts isolated from organically and conventionally grown grapes, and during the subsequent fermentation with or without starter cultures in six different commercial wineries. Methods and Results: PCR‐RFLP screening of isolates revealed the involvement of ten different species. Saccharomyces cerevisiae, scarcely isolated from grapes, was the dominant species during the latter phases of fermentation, identifying 108 different genotypes by means of SSR analysis. Species and strains’ diversity and presence were strongly influenced by the farming system used to grow the grapes and the system of vinification. Conclusions: Organic farming management was more beneficial in terms of diversity and abundance than the conventional one. Induced fermentation generated a great replacement of native yeasts. Although winery‐resident yeasts resulted to be predominant in the process, some noncommercial strains originally in the vineyard were found in final stages of the fermentation, confirming that autochthonous strains of S. cerevisiae are capable to conduct the fermentation process up to its end. Significance and Impact of the Study: The study of natural yeast communities from commercial vineyards and wineries is an important step towards the preservation of native genetic resources. Our results have special relevance because it is the first time that the real situation of the yeast ecology of alcoholic fermentation in commercial wineries belonging to the relevant wine‐producing Appellation of Origin ‘Vinos de Madrid’ is shown.     

Patterns of species co-occurrence and density compensation: a test for interspecific competition in bat ectoparasite infracommunities

Parasites constitute an ideal system with which to investigate patterns and mechanisms of community structure and dynamics. Nevertheless, despite their prevalence in natural systems, parasites have been examined less often than other organisms traditionally used for testing hypotheses of community assembly. In the present study, we investigate possible effects of competitive interactions on patterns of distribution (co‐occurrence) and density among a group of streblid bat flies parasitic on short‐tailed fruit bats, Carollia perspicillata. Using null model analyses of species co‐occurrence, we did not find evidence that competition affects the distribution of bat fly species across hosts. Moreover, when non‐infested hosts were included, analyses showed evidence for interspecific aggregation, rather than for the segregation predicted by competition theory. Partial Pearson correlations among bat fly species densities showed no evidence of negative covariation in two of three cases. In the species pair for which a significant negative correlation was found, a visual analysis of plotted covariation indicated a constraint line, suggesting that competition between these two species might become operational only in some infracommunities when abundances of bat flies approach a maximum set by one or more limiting resources. Moreover, when a community‐wide estimation of the significance of density compensation was calculated, the result was not significant. Overall, we find no evidence that competition influences the distribution of bat flies on their hosts, and mixed support for effects of competition on the densities of species. These results are consistent with the idea that competition plays a role in structuring natural communities, but in many systems its effects are context‐dependent and might not be important relative to other factors. Wider analyses across taxonomic and environmental gradients and a detailed consideration of the different hypothesized effects of competition are necessary to fully understand the importance of competition on natural communities.     

Possibilities of the use of vinasses in the control of fungi phytopathogens

The purpose of this research was to study the biocide effect of three agroindustrial subproducts, concretely sugar beet, sugar cane and wine vinasse. Results from in vitro testing determined that wine vinasse is what shows a 100% capacity to suppress fungal growth with concentrations between 5% and 7% for Fusarium oxysporum f.sp. melonis race 0 and 1, Sclerotinia sclerotiorum, Pythium aphanidermatum and Phytophthora parasitica and 10-15% for F. oxysporum f.sp. radicis-cucumerinum. On the other hand, sugar cane vinasse produced an increase at high concentrations and sugar beet vinasse showed an approximate 100% suppressor effect on fungal growth for only some of the phytopathogens tested: S. sclerotiorum (15%), P. aphanidermatum (7%), P. parasitica (15%) and F. oxysporum f.sp. radicis-cucumerinum (15%). In the soil samples analyzed none of the three vinasse extracts decreased fusaric microbiota, producing an increase in the three samples tested. This would implicitly convey an improvement in soil quality by producing a potential increase in bacterial and fungal microbiota.     

Surveillance of Arboviruses in Primates and Sloths in the Atlantic Forest,Bahia, Brazil

From 2006 through 2014, we conducted seroepidemiological surveys on non-human primates and sloths to investigate the possible circulation of arboviruses in Bahia Atlantic Forest, Brazil. We collected a total of 196 samples from 103 Leontopithecus chrysomelas, 7 Sapajus xanthosternos, 22 Bradypus torquatus and 7 Bradypus variegatus. Serum samples were tested using neutralization test and hemagglutination inhibition test to detect total antibodies against 26 different arboviruses. The overall prevalence of arboviruses was 36.6% (51/139), with the genus Flavivirus having the highest prevalence (33.1%; 46/139), followed by Phlebovirus (5.0%; 7/139), Orthobunyavirus (4.3%; 6/139) and Alphavirus (0.7%; 1/139). Monotypic reactions suggest that the wild animals were exposed naturally to at least twelve arboviruses. Added results from the neutralization test, animals were exposed to thirteen arboviruses. Most of these viruses are maintained in transmission cycles independent of human hosts, although antibodies against dengue virus serotypes 1, 2 and 3 were found in this study. To our knowledge, this is the first study reporting exposure to arboviruses in L. chrysomelas, S. xanthosternos and B. torquatus. Our results also highlight that the Southern Bahia Atlantic Forest has a variety of vertebrate hosts and potential vectors, which may support the emergence or re-emergence of arboviruses, including those pathogenic to humans.     

Association of the whale shark Rhincodon typus with the cannonball jellyfish Stomolophus meleagris

This study describes the first record of the whale shark Rhincodon typus association with the cannonball jellyfish Stomolophus meleagris in the Gulf of California, Mexico. Whale sharks were observed swimming and feeding among swarms of jellyfish, suggesting competition and predatory behaviour given the overlap in food preferences between both species. This finding is relevant because of the species‐wide distribution and the importance of these interactions, which should be considered in conservation strategies of R. typus and management of cannonball jellyfish fisheries.     

Four functional GnRH receptors in zebrafish: analysis of structure, signaling, synteny and phylogeny

Reproduction in all vertebrates requires the brain hormone gonadotropin-releasing hormone (GnRH) to activate a cascade of events leading to gametogenesis. All vertebrates studied to date have one to three forms of GnRH in specific but different neurons in the brain. In addition, at least one type of GnRH receptor is present in each vertebrate for activation of specific physiological events within a target cell. Humans possess two types of GnRH (GnRH1 and GnRH2) but only one functional GnRH receptor. Zebrafish, Danio rerio, also have two types of GnRH (GnRH2 and GnRH3), although in contrast to humans, zebrafish appear to have four different GnRH receptors in their genome. To characterize the biological significance of multiple GnRH receptors within a single species, we cloned four GnRH receptor cDNAs from zebrafish and compared their structures, expression, and cell physiology. The zebrafish receptors are 7-transmembrane G-protein coupled receptors with amino-acid sequence identities ranging from 45 to 71% among the four receptors. High sequence similarity was observed among the seven helices of zebrafish GnRHRs compared with the human GnRHR, the green monkey type II GnRHR, and the two goldfish GnRHRs. Also, key amino acids for putative ligand binding, disulfide bond formation, N-glycosylation, and G-protein coupling were present in the extracellular and intracellular domains. The four zebrafish receptors were expressed in a variety of tissues including the brain, eye, and gonads. In an inositol phosphate assay, each receptor was functional as shown by its response to physiological doses of native GnRH peptides; two receptors showed selectivity between GnRH2 and GnRH3. Each of the four receptor genes was mapped to distinct chromosomes. Our phylogenetic and syntenic analysis segregated the four zebrafish GnRH receptors into two distinct phylogenetic groups that are separate gene lineages conserved throughout vertebrate evolution. We suggest the maintenance of four functional GnRH receptors in zebrafish compared with only one in humans may depend either on subfunctionalization or neofunctionalization in fish compared with mammalian GnRH receptors. The differences in structure, location, and response to GnRH forms strongly suggests that the four zebrafish GnRH receptors have novel functions in addition to the conventional activation of the pituitary gland in the reproductive axis.