Influence of year and genetic factors on chilling injury susceptibility in peach (<Emphasis Type="Italic">Prunus persica</Emphasis> (L.) Batsch)

Chilling injury (CI) is a major physiological problem limiting consumption and export of peach and nectarine (Prunus persica (L.) Batsch). To clarify the genetic basis for chilling injury, inheritance of the major CI symptoms mealiness, flesh browning, flesh bleeding, and flesh leatheriness were examined over three years in two related peach progenies. In addition, genetic relationships among traits and the year-to-year variation in trait performance in these progenies were tracked. Both populations also segregated for Freestone-Melting flesh (F-M) and yellow flesh. There were significant differences in CI symptoms among years. The major gene endoPG, which controls the F-M locus, provides resistance to mealiness in non-melting flesh fruit. Only fruit with melting flesh can develop mealiness if the tree possesses other genetic susceptibility factors and/or experiences inducing conditions. The F-M locus also greatly influences susceptibility to flesh bleeding, although the physiological mechanism for this disorder is unclear and may be controlled by a different gene closely linked to endoPG. Unlike mealiness, flesh bleeding occurred primarily in non-melting flesh fruit, particularly when the fruit is white-fleshed. Flesh browning incidence was greater in mealy fruit and was not associated with flesh bleeding. Breeding for CI resistance is thus a viable long-term strategy to reduce losses in the fresh and processed peach and nectarine industries. This study is an important first step to understanding genetic control of CI symptoms in peach.     

Early settlement and growth of stocked European glass eels in a fragmented watercourse

One of the actions that has been implemented to support the recovery of the panmictic population of European eel is stocking of waterbodies where natural recruitment is low or null. However, growth conditions of the stocked eels can vary greatly. This circumstance emphasises the importance to determine ideal habitat conditions to contribute to the success of stocking actions and, consequently, to increase the production of silver eels. This study aims to evaluate the early settlement and growth of stocked glass eels in the upper reaches of a fragmented river. Stocking was carried out, in 2014, at three sites of an inland tributary of the Mondego river basin (Central Portugal), and its monitoring was conducted during the following two years, until 2016, along with the collection of environmental and hydromorphological parameters. The results showed a successful dispersion throughout the study area. Growth varied spatially, although environmental parameters have not clearly explained this variation, but overall with high growth rates and a positive allometric growth in this early stage of stocking, suggesting a good condition of the stocked individuals. This study showed that these upper reaches of fragmented watercourses, a shared feature amongst most European rivers that are currently inaccessible for natural recruitment, may be suitable habitats for eel stocking.     

Dietary tryptophan supplementation does not affect growth but increases brain serotonin level and modulates the expression of some liver genes in zebrafish (Danio rerio)

This study aimed at assessing the effects of the dietary tryptophan (Trp) supplementation on growth and feed utilization, brain serotonin content, and expression of selected liver genes (involved in the liver serotonin pathway, protein synthesis degradation, and antioxidant activity) in zebrafish. A growth trial was conducted with zebrafish juveniles fed five experimental isoproteic (40%DM) and isolipidic (8%DM) fishmeal-based diets containing graded levels of Trp: a Trp-non-supplemented diet (diet Trp0, with 0.22% Trp) and four Trp-supplemented diets containing 2–16 times higher Trp content (diets Trp2, Trp4, Trp8, and Trp16 with 0.40, 0.91, 2.02, and 3.34% Trp, respectively). Diets were tested in quadruplicate, with fish being fed twice a day, 6 days a week for 6 weeks to apparent visual satiation. At the end of the trial, growth performance and feed utilization were assessed, and fish from all experimental groups were sampled for whole-body composition analysis. In addition, fish fed low (Trp0), medium (Trp4), and high (Trp16) Trp diets were also sampled for analysis of brain serotonin content and liver gene expression. Tested tryptophan levels did not influence growth performance nor feed intake. However, values of energy and nitrogen retention as well as body energy content indicate a better feed utilization with diets containing around 0.9% and 2.0% DM Trp. Brain serotonin content increased with increasing dietary tryptophan levels. In addition, regarding liver genes, dietary treatment had a modulatory effect on the expression of Htr1aa and Htr2cl1 genes (encoding for serotonin receptors), TPH1a gene (encoding for tryptophan hydroxylase, the rate-limiting enzyme in the synthesis of serotonin from tryptophan), TOR gene (involved in protein synthesis), and Keap1 gene (involved in antioxidant responses).

     

Testing foliar nutritional changes in space and over time in greenhouse tomato

The aim of this trial was to study the spatial and temporal variability of the leaf nutrient concentration in tomato intensive crop under greenhouse, to know the number of sub-samples needed to be taken to obtain a representative sample and the influence by the position in the greenhouses. The experiment consisted on the selection of 20 sample points over the greenhouse with one tomato plant per sample point. One fully expanded leaf by sample point with an interval of a week were taken. Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), sodium (Na), and chloride (Cl) were determined in each sample. According to these results, N, P, K, S, Cl, and Na concentration showed no variation over the time. The spatial variability of N, P, and K could be related with the light intensity and yield. The suggested number of leaf sub-sample ranging from 25 to 126 depending on nutrient.     

Using pedological knowledge to improve sediment source apportionment in tropical environments

Journal of Soils and Sediments - Soils are important regulators of Critical Zone processes that influence the development of geochemical signals used for sediment fingerprinting. In this study,...     

Acetate and sulphate as regulators of potential methane production in a tropical coastal lagoon

Journal of Soils and Sediments - We evaluated the influence of acetate and sulphate addition on methanogenesis in sediment layers of cores of different carbon and sulphate concentrations from the...     

Electron paramagnetic resonance (EPR) spectroscopy as a tool for the characterization of biochar from guava waste

Journal of Soils and Sediments - The ability of biochars prepared from pyrolysis of guava pulp and seed industrial wastes to form complexes with the ions vanadyl (VO2+), a Pearson hard acid, and...     

Lanthanides and yttrium in the sediments of the lower Minho River (NW Iberian Peninsula): imprint of tributaries

Purpose

Rare earth elements have been used as sediment tracers in river, estuarine and coastal environments but rarely applied as fluvial tributary tracers. Lanthanides (Ln) and yttrium (Y) were quantified in fluvial sediments of the Minho River lower course (NW Iberian Peninsula), where the catchment contains heterogeneous lithologies, to define the characteristic imprints of tributaries and their relevance in the riverine system.

Materials and methods

Surface sediments were sampled at 36 points in the lower Minho riverbed and its nine main tributaries.The <?2-mm fraction was sieved and ground, and ≈?100 mg was completely acid-digested with HF and aqua regia in closed Teflon bombs at 100 °C for 1 h. The residue was evaporated, re-dissolved with HNO₃ and Milli-Q water, heated 20 min at 75 °C and diluted to 50 cm³ with Milli-Q water. Lanthanides and yttrium were determined using a quadrupole ICP-MS equipped with a Peltier impact bead spray chamber and a concentric Meinhard nebuliser. Blanks accounted for less than 1% of the element concentrations in the samples. The precision and accuracy of the analytical procedures were controlled through reference materials AGV-1 and MAG-1.

Results and discussion

Contents ranged from 22 to 153 mg Ln kg^?1 and 1.5–22.9 mg Y kg^?1 and ES-normalised light-heavy Ln fractionation, (L_N/H_N), varied between 0.6 and 2.6. These wide ranges, together with Eu and Ce anomalies and element-by-element Ln, varied with changes in parental rocks of the lower Minho basin. Minho sediments showed negative Ce anomalies (0.81?±?0.29) and positive Eu anomalies (1.23?±?0.18). Sediments received traces of granitic pegmatites and gneissic peralkaline rocks from two tributaries: the Gadanha (22.9 mg Y kg^?1; 83 mg Ln kg^?1; 0.60 L_N/H_N; 0.51 Eu/Eu*; 0.88 Ce/Ce*) and the Louro (15.9 mg Y kg^?1; 110 mg Lnkg^?1; 0.97 L_N/H_N; 0.69 Eu/Eu*; 1.49 Ce/Ce*). The Tamuxe tributary, flowing through a slate and quartzite fault, provided the lowest source (1.6 mg Y kg^?1; 28 mg Ln kg^?1; 2.48 L_N/H_N; 1.01 Eu/Eu*; 0.55 Ce/Ce*).

Conclusions

Lanthanide and Y signatures in sediments may be used to trace land-tributary-river influences. The imprints are observed downstream of fluvial confluences but not in all cases, responding to basin lithological changes, particularly for pegmatites and peralkaline rocks. The general REE trend is described using Y contents only. Tributaries, which are responsible for one-fifth of the Minho water load, provide one-half of their sediments. Non-homogeneous sediment patterns may be magnified in dammed rivers such as the Minho.

     

The prevalence and avidity of Toxoplasma gondii IgG antibodies in pigs from Brazil and Peru

Raw or inadequately cooked pork is an important source of Toxoplasma gondii infection, and the infection rate in animals used as human food, is an important risk predictor. The prevalence of this infection was estimated in 396 sera from 5-month old pigs obtained at abattoirs in S?o Paulo, Brazil (300) and Lima, Peru (96). The seroprevalence was higher in pigs from Peru (32.3%) as compared to Brazil (9.6%), as detected by ELISA and Western blot. Hemagglutination gave poor resolution which was not useful for the diagnosis of T. gondii infection. Specific antibody avidity is correlated with infection time, as shown in experimentally infected piglets. Using an arbitrary cut-off of 50% avidity index, Brazilian pigs were found to be more recently infected than Peruvian pigs. Pork should be considered a significant source of human T. gondii infection both in Brazil and Peru. Avidity assays could help in the detection of the time of T. gondii infection in pigs, allowing preventive management.