Single-tube nested real-time PCR as a new highly sensitive approach to trace hazelnut

Hazelnut is one of the most commonly consumed tree nuts, being largely used by the food industry in a wide variety of processed foods. However, it is a source of allergens capable of inducing mild to severe allergic reactions in sensitized individuals. Hence, the development of highly sensitive methodologies for hazelnut traceability is essential. In this work, we developed a novel technique for hazelnut detection based on a single-tube nested real-time PCR system. The system presents high specificity and sensitivity, enabling a relative limit of detection of 50 mg/kg of hazelnut in wheat material and an absolute limit of detection of 0.5 pg of hazelnut DNA (1 DNA copy). Its application to processed food samples was successfully achieved, detecting trace amounts of hazelnut in chocolate down to 60 mg/kg. These results highlight the adequacy of the technique for the specific detection and semiquantitation of hazelnut as potential hidden allergens in foods.     

Water Lettuce Pistia stratiotes L. Response to Lead Toxicity

The effects of one of the most toxic heavy metals, lead (Pb), applied in two different concentrations and combined with chelate application were investigated on the water macrophyte (Pistia stratiotes L.) physiology. The influences were observed by the chlorophyll and free amino acid content determination. Also the lead accumulation in macrophyte biomass was investigated to assess the potential efficiency of this plant for rhizofiltration of highly Pb-polluted water. Na EDTA and Na citrate were used as chelates and Pb(NO₃)₂ as lead supplement. The application of organic chelates simulated conditions of an induced phytoextraction process. Statistical analyses were performed as a one-way ANOVA with a subsequent Tukey HSD test at a level of P < 0.05. Pb contents in both root and leaf tissues gradually increased with increasing Pb concentrations in the nutrient solution. More lead was accumulated in leaves than in roots within all treatments. The total chlorophyll content decreased with increased Pb concentration and with a higher content of chelates. The chelate addition increased the total amino acid content in leaves but decreased the total amino acid content in roots. The addition of lead with chelates decreased the dry biomass weight. However, water macrophyte showed extremely high lead accumulation in biomass in the short term (up to 8 days) and this accumulation potential could be used for relatively fast and effective decrease of high concentration of this risk element in contaminated water or sewage.     

Synchronization of ovulation in brook char (Salvelinus fontinalis, Mitchill 1814) using emulsified d-Arg6Pro9NEt sGnRHa

Effects of physiological saline (PS)-dissolved or Freund′s incomplete adjuvant (FIA)-emulsified sGnRHa on the induction and advancement of ovulation in brook char were assessed. Two-year-old females were randomly divided into 5 groups. Groups A and B received intraperitoneal injection of FIA-emulsified sGnRHa (sGnRHa-FIA) at dosages of 50 and 25 μg kg^?1 body weight (BW), respectively. Females in group C were treated with a double injection (DI) of PS-dissolved sGnRHa (sGnRHa-PS) at 25 μg kg^?1 BW spaced 3 days apart. Fish in group D received a 25 μg kg^?1 BW single injection (SI) of sGnRHa-PS. Group E was established as a control group. After stripping, ovarian plasma pH level was measured, and an egg sample was taken from each female to record egg weight and diameter and survival to the eyed stage. Females in the GnRHa-treated groups ovulated significantly earlier than did females in the control group (P < 0.01). No significant differences were found among GnRHa-treated groups in ovulation dynamics and mean time to ovulation. Ovarian fluid pH was significantly higher in groups A, B, and C compared to control group E (P < 0.05). Significantly lower egg weight was found only in group B (P < 0.01), although all advanced groups tended to have lower egg weight than the control group. Egg diameters paralleled egg weight. Survival to the eyed stage was significantly higher in GnRHa-advanced groups compared to the control. A negative relationship was found between egg weight end eyed eggs percent (R ² = 0.26). No pre-spawning or post-spawning mortality was observed during a 6-month period. Neither sGnRHa-PS nor sGnRHa-FIA are associated with negative influences on the health of females. The sGnRHa-FIA injections proved to exhibit the same efficacy as the DI protocol with sGnRHa-PS. Although no statistical differences were found in ovulation dynamics, we do not recommend the use of SI with sGnRHa-PS in brook char.     

The effect of fish size and stocking density on the weaning success of pond-cultured pikeperch Sander lucioperca L. juveniles

The effect of initial fish size (small with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g, medium with TL = 56.2 ± 2.7 mm and W = 1.66 ± 0.4 g, and big with TL = 71.0 ± 3.2 mm and W = 2.95 ± 0.65 g) and stocking density of identical fish with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g (1; 2; 4; 8 fish l^?1) on weaning success was evaluated in pond-cultured pikeperch. The trial was divided into weaning (12 days) and post-weaning (16 days) periods. Small juveniles reached significantly higher specific growth rate (SGR = 1.6 ± 0.2 % day^?1) and survival rate (S = 81.7 ± 2.7 %) and lower cannibalism (C = 3.0 ± 0.75 %) compared to medium and large juveniles (SGR = 0.3–0.5 % day^?1, S = 65.3–76.5 %, C = 6.5–7.5 %) during the weaning period. The higher survival rate was found at the two higher densities (S = 72.0–79.1 %) during the weaning period. The lowest survival rate (S = 38.9 ± 2.7) was observed at the lowest fish density. Fish stocking density did not affect growth, condition, or cannibalism rate during the weaning period. Similar trends of growth, survival, and cannibalism of weaned juveniles were observed during the post-weaning period. A mass weaning trial verified experimental results showing small pikeperch juveniles to reach satisfactory growth rate (SGR = 1.4 ± 0.1 and 7.2 ± 0.2 % day^?1), survival (S = 78.7 ± 3.0 % and 97.6 ± 1.0 %), and cannibalism (C = 4.0 ± 1.5 % and 2.5 ± 1.0 %) rates during the weaning and post-weaning periods. No body or fin deformities of weaned juveniles were observed.     

Do biological expansion factors adequately estimate stand-scale aboveground component biomass for Norway spruce?

We developed site specific component (stem, branch, and foliage) biomass functions for two sites in Sweden (64° and 57° North latitude) where four treatments (control, irrigated, fertilized, irrigated plus fertilized) were applied in the existing Norway spruce stands (Picea abies L. Karst.) for 17 years. We tested for site effects in the component biomass equations and compared site specific biomass estimates to those generated using published functions ( 19 and 39). Site effects were significant for all components and indicated it would be unlikely to generate equations that well estimate biomass across the Norway spruce range as implicitly indicated in our efforts to generate species biomass expansion factors. We rejected our hypothesis that the published functions would well estimate component biomass for control plots. The published functions did not compare well with site specific component biomass estimates for the other treatments; both published functions well estimated stem mass up to stem mass of 25 Mg ha⁻¹, beyond which stem mass was overestimated, and both functions over and under estimated foliage and branch mass. Nor did the published functions compare well with each other, with stem, foliage and branch mass estimate differences of 12, 55, −8% and 11, 77, and 59% for the southern and northern sites, respectively, when averaged over all treatments and years. Adding limiting resources through fertilization increased stem, foliage and branch mass 57, 11, 18% and 120, 37, and 69% at the southern and northern sites, respectively, which would increase carbon sequestration and available stemwood and bioenergy materials. We recommend that more effort is spent in process-based modeling to better predict mass at a given site and ultimately provide better estimates of carbon sequestration and bioenergy material production changes.     

Pedigree and mating system analyses in a western larch (Larix occidentalis Nutt.) experimental population

?The mating pattern and gene flow in a western larch (Larix occidentalis Nutt.) experimental population was studied with the aid of microsatellite markers and a combination of paternity-mating system analysis. The commonly difficult to assess, male gametic contribution was determined with 95% confidence and its impact on genetic gain and diversity was determined.

? Male fertility success rate ranged between 0 and 11%. Male reproductive output parental imbalance was observed with 50% of the pollen being produced by the top 5% of males while the lower 39% males only produced 10% of the pollen.

? A significant difference was observed between male effective population size (genetic diversity) estimates from paternity assignment compared to those based on population’s census number (21 vs. 41); however, this difference did not affect estimates of genetic gain.

? A total of 221 full-fib families were identified (sample size range: 1–8) and were nested among the studied 14 seed-donors.

? A combination of paternity-mating system analysis is recommended to provide a better insight into seed orchards’ mating dynamics. While pollen flow tends to inflate mating system’s outcrossing rate, the paternity analysis effectively determined the rate and magnitude of contamination across receptive females.

     

Changes of sperm morphology,volume, density,and motility parameters in northern pike during the spawning period

Sexually mature males (BW?=?1600?±?150 g and TL?=?235?±?30 mm) of northern pike (Esox lucius L.) were randomly selected from a pond to record changes in their sperm quality parameters (spermatozoa morphology, sperm volume, density, and motility parameters) during the spawning season. The morphological and motility parameters changed significantly during the reproductive season with following trends. Only, head width was not changed during the spawning season. The longest spermatozoa and its flagellar length were found at the middle of spawning period (TL?=?38.24?±?0.37 μm and 35.14?±?0.26 μm) and shortest at the beginning of spawning period (TL?=?34.81?±?0.29 μm and 32.53?±?0.18 μm). Other morphological characters were always the lowest at the beginning of spawning period. Sperm volume was changed from 0.33?±?0.3 ml in February, 0.43?±?0.2 ml in March to 0.24?±?0.1 ml in April, and density from 16.2?±?0.2?×?109 spermatozoa ml^?1 in February, 19.4?±?0.2?×?109 spermatozoa ml^?1 in March to 4.8?±?0.2?×?109 spermatozoa ml^?1 in April. Same sperm velocity was observed in all spawning terms at 10 and 20 s after activation. Higher velocity was found at 30 and 40 s after activation in sperm collected at the middle and the end of spawning period. Significantly, higher percentage of motile sperm was observed at 20, 30, and 40 s after activation in sperm sampled at the end of spawning period. This study supports the hypothesis that longer spermatozoa swim faster.