Leucettamols, Bifunctionalized Marine Sphingoids, Act as Modulators of TRPA1 and TRPM8 Channels

Leucettamols, bifunctionalized sphingoid-like compounds obtained from a marine sponge Leucetta sp., act as non-electrophilic activators of the TRPA1 channel and potent inhibitors of the icilin-mediated activation of the TRPM8 channel, while they are inactive on CB₁, CB₂ and TRPV1 receptors. Leucettamols represent the first compounds of marine origin to target TRPA1 and the first class of natural products to inhibit TRPM8 channels. The preparation of a small series of semi-synthetic derivatives revealed interesting details on the structure-activity relationships within this new chemotype of simple acyclic TRP modulators.     

Sowing time and prediction of flowering of different hemp (Cannabis sativa L.) genotypes in southern Europe

Fibre hemp can be grown under a wide range of agro-ecological conditions, but it requires special attention for several physiological features and crop management. A management strategy in order to reduce inputs and thus achieve acceptable yield could be achieved optimizing sowing time. With this respect, the effects of sowing date on hemp biology and yield was studied, using two monoecious and two dioecious genotypes. Field experiments were carried out in two subsequent years (2003-2004) in South of Italy, using drip irrigation system. Sowing time, in the two year period, ranged between March 10th and July 22nd. Optimal sowing time was observed between the end of April and the first three weeks of May; in that range, the dioecious Fibranova yielded the most in terms of aboveground biomass and stem dry yield, followed by Tiborszallasi, while the two monoecious showed the lowest yield. On the contrary, before and after that period, the shorter day length caused an early floral induction that strongly reduced stem and fibre elongation, and thus aboveground dry biomass and consequently stem yields. Based on this study a simulation model focusing on flowering prediction in Mediterranean environment was developed.     

Nutritional evaluation of “Braquiarão” grass in association with “Aroeira” trees in a silvopastoral system

This study aimed at evaluating the influence of a silvopastoral system (SPS) composed of “Aroeira” trees (Myracrodruon urundeuva) on the nutritional value of Brachiaria brizantha cv. Marandu forage grass over the rainy season. The experiment was conducted in the SPS located in the “Cerrado” biome in Lagoa Santa County, Minas Gerais state, Brazil, in the agricultural year of 2004–2005. It was evaluated the influence of “Aroeira”, whose density in the area was 140 trees/ha, on the following parameters of the B. brizantha cv. Marandu forage grass: forage mass harvest above stubble height, morphogenic attributes, bromatological composition and nutritional value. The effects of “Aroeira” trees on the micro-climatic conditions were also evaluated. The experiment adopted a randomized block design with five blocks (cutting seasons), two treatments (a shaded pasture—B. brizantha cv. Marandu shaded by M. urundeuva—and a pasture in full sun—B. brizantha cv. Marandu in full sun), and three replicates. The tree component, composed of the tree species M. urundeuva in the experimental density adopted, increased dry matter and crude protein of the forage mass harvest above stubble height, without affecting the concentration of neutral detergent fibre or acid detergent fibre, thus causing dry matter and organic matter in vitro degradability as well as effective degradability of the forage grass to remain the same as those obtained in full sun. Therefore, the results of this study show the possibility of using trees and grass to increase both animal production and environmental services.     

Genetic diversity and relatedness estimates for captive barramundi (Lates calcarifer,Bloch) broodstock informs efforts to form a base population for selective breeding

Aquaculture of barramundi or Asian seabass (Lates calcarifer) is growing in both Australia and Southeast Asia and there is substantial interest to improve production efficiency through selective breeding. The establishment of a large and genetically diverse base population is a prerequisite for a sustainable and long‐term productive breeding program. Before selective breeding programs can begin for Australian barramundi it is important to assess the overall genetic diversity of current captive broodstock populations. To address this question, 407 captive barramundi broodstock from eight separate Australian broodstock populations were genotyped using 16 polymorphic microsatellite DNA markers. A Bayesian STRUCTURE analysis indicated that captive Australian broodstock are broadly divided into two genetic stocks. Multivariate analysis between broodstock individuals and pairwise F_ST between broodstock populations also supported the existence of two stocks. Comparisons with data obtained from natural stocks suggested that hatchery individuals were either sourced from the two stocks or represented an admixture between them. Genetic diversity was low within each broodstock population (allelic richness ranged from 2.67 to 3.42 and heterozygosity ranged from 0.453 to 0.537) and relatedness estimates within hatcheries were generally low (average r was equal to 0.141). We recommend sourcing captive individuals according to high levels of neutral genetic diversity and low levels of relatedness for the establishment of a base population. We also make recommendations about including genetically diverse wild individuals.     

Biostimulant activity of two protein hydrolyzates in the growth and nitrogen metabolism of maize seedlings

Two protein hydrolyzate–based fertilizers (PHFs), one from alfalfa (AH) and one from meat flour (MFH), were studied chemically and biologically. AH and MFH revealed a different degree of hydrolysis and a different amino acid composition. The biostimulant activity was investigated using two specific and sensitive bioassays of auxins and gibberellins. Extracts of AH and MFH elicited a gibberellin‐like activity and a weak auxin‐like one. To improve our understanding of the biostimulant activity, AH and MFH were supplied to maize plants and their effect on growth and nitrate metabolism was studied. Both PHFs increased root and leaf growth and induced morphological changes in root architecture. Besides, the treatments increased nitrate reductase (NR) and glutamine synthetase (GS) activities, suggesting a positive role of the two hydrolyzates in the induction of nitrate conversion into organic nitrogen. Moreover, treatments enhanced GS1 and GS2 isoforms in maize leaves. The latter isoform, amounting to 5‐ to 7‐fold the level of the former, appears to be a superior form in the assimilation of ammonia. The high NR and GS activities together with the high induction of GS isoforms indicate a stimulatory effect of the two PHFs on the assimilation of nitrate. In addition, a role of amino acids and small peptides of the two PHFs is suggested in the regulation of the hormone‐like activity and nitrogen pathway.     

A phytoplasma representative of a new subgroup, 16SrXIII-E, associated with Papaya apical curl necrosis

Papaya apical curl necrosis (PACN) has frequently been observed in several Brazilian states. Affected plants exhibit foliar chlorosis, curvature of the apex, shortening of the internodes leading to bunching of the crown leaves, necrosis of the young apical parts, leaf drop, and dieback. Naturally infected plants were sampled and subjected to PCR assays, which confirmed that a phytoplasma was associated with the disease. Sequencing of the 16S rRNA gene, conventional and computer-simulated RFLP analyses, and phylogenetic analysis allowed the determination of the PACN phytoplasma as a representative of a new subgroup, designated 16SrXIII-E. The phytoplasmas of various 16Sr groups, including 16SrI, 16SrII, 16SrX, 16SrXII, and 16SrXVII, are known to be involved in anomalies in papaya plants in several countries. However, the present study reports, for the first time, the occurrence of a 16SrXIII phytoplasma in association with a papaya disease.     

Paired-site approach for studying soil organic carbon dynamics in a Mediterranean semiarid environment

This work investigated the effects of land cover and land-use change (LUC) on the ability of a soil to store carbon (C) and reduce carbon dioxide (CO₂) emissions, in a Mediterranean area. Using a paired-site approach, we estimated the effect of land-cover change on the C stock from 1972 to 2008 in a natural reserve (Grotta di Santa Ninfa) in western Sicily. We selected 15 paired sites representative of five LUCs. We studied the effect of land use on soil organic C (SOC) content in bulk soil and in different particle-size fractions (2000-1000 μm, 1000-500 μm, 500-250 μm, 250-63 μm, 63-25 μm, and < 25 μm). Laboratory incubation of the soil samples was conducted to measure CO₂ evolution in bulk soil collected at two different depths from each paired site. We found that the conversion of natural vegetation to orchards (vineyards and olive groves) resulted in SOC decreases ranging from 27% to 50%. The conversion from vineyards to arable land led to a 9% decrease in SOC, whereas the opposite caused a 105% gain. When arable land was replaced by Eucalyptus afforestation, a 40% increase in SOC was observed. SOC decline occurred mainly in coarser soil fractions, whereas the finest fractions were not influenced by land use. We calculated an overall SOC reduction of 63% in the study area, corresponding to a 58 Mg ha^− 1 SOC loss in less than 30 years. Our results indicate that land-use conversion, vegetation type, and management practices that control the biogeochemical and physical properties of soil could help reduce CO₂ emissions and sequester SOC.     

The endothelial nitric oxide synthase/nitric oxide system is involved in the defective quality of bovine oocytes from low mid-antral follicle count ovaries

In a previous survey concerning cows of reproductive age, we demonstrated that oocytes isolated from ovaries with <10 medium antral follicles of 2 to 6 mm in diameter (low ovaries; Lo) show less developmental competence than oocytes collected from ovaries with >10 medium antral follicles (high ovaries; Hi). The aim of the present study was to evaluate whether a defective endothelial nitric oxide synthase/nitric oxide (eNOS/NO) system and vasculature in healthy medium antral follicles is likely to reduce oocyte competence from Lo ovaries. Thus, experiments were conducted to 1) immunolocalize eNOS protein during folliculogenesis; 2) quantify eNOS protein/vasculature in the follicle wall; and 3) verify if NO donor, S-nitroso acetyl penicillamine (SNAP) administration during in vitro maturation affects developmental competence of oocytes isolated from Lo ovaries. Endothelial nitric oxide synthase protein was detected in granulosa and theca cells, as well as in blood vessels from primordial to antral follicles. Quantitative analysis indicated that in medium antral follicles from Lo ovaries, eNOS protein expression and vasculature were reduced (P < 0.05). The addition of SNAP improved blastocyst and hatching rates of oocytes from Lo ovaries, promoting a percentage similar to oocytes from Hi ovaries, and reduced the percentage of apoptotic nuclei in in vitro-produced blastocysts (P < 0.05). Results from our study suggest that in bovine ovaries with small mid antral follicle number, a defective eNOS/NO system is related to a reduced follicle vasculature and may affect oocyte quality, thus inducing a premature decline of fertility.     

Development of an indirect ELISA-NcSRS2 for detection of Neospora caninum antibodies in cattle

Neosporosis is of alarming economic concern in the cattle industry. The effectiveness of diagnostic tests for detecting specific antibodies against Neospora caninum is hampered by potential cross-reaction with other coccidia. Use of a single specific antigen might improve test specificity. An indirect enzyme-linked immunosorbent assay (ELISA) was developed using the truncated protein NcSRS2 expressed in Escherichia coli. The ELISA results were compared with those of the indirect fluorescence antibody test (IFAT). Receiver Operating Characteristic (ROC) and Tests in the Absence of a Gold Standard (TAGS) analysis revealed an assay having 96% specificity and 95% sensitivity when applied to 145 positive and 352 negative sera from two distinct cattle populations. Using OD ≤ 0.095 as the cut-off point, the assay's negative and positive predictive values ranged from 98.8% to 50.8% and from 58.8% to 99.1%, respectively, depending on neosporosis prevalence in a given area. The novel ELISA-NcSRS2 format described in the present report constitutes a specific and sensitive method for detecting N. caninum in cattle.