Adaptation and Validation of a Methodology for the Measurement of Calcium Fractions in Fruits

Calcium (Ca) content of fruit is related to fruit quality. However, total content alone is insufficient to judge fruit quality; calcium partitioning and chemical form are also important. There are multiple validated methods for determining total calcium content. However, methodologies to measure calcium fractions are not widely known and tend to be complex, affecting their accuracy. Here, based on previous work, we aim to adapt and validate a method for the extraction of the various forms of calcium in fruits. The main modification was freezing samples to minimize the loss of sample material in the procedure, reducing the centrifugation time and speed, and the addition of nitric acid (HNO₃) to improve digestion and eliminate interference from the matrix. An experiment with table grape berries cv. Thompson seedless in harvest and Postharvest (35 days) was carried out. The results of the total calcium were compared with the conventional methodology of calcination and inductively coupled plasma (ICP) measurement. We detected no and no significant differences between the two tested methods. Electron Microscope - Energy-dispersive X-ray spectroscopy analysis (SEM-EDS) and the presence of calcium oxalates were verified.     

Influence of practitioner expertise during early pregnancy diagnosis on pregnancy loss rate: A controlled,blinded trial

A controlled field trial was conducted to assess the potential influence of practitioner inexperience during early pregnancy diagnosis with ultrasound (PD‐US) on the risk of pregnancy loss. A veterinarian with more than 10 years’ experience in PD‐US (Vet‐A) and a veterinarian with fewer than 12 months’ experience at the start of the study (Vet‐B) visited the same dairy farm once a week for 33 and 26 weeks, respectively. The two veterinarians did not interact with each other at any time during the study, nor did they know that their data would later be used in this study. Using the same farm scanner, they performed PD‐US at 28–34 day after breeding, together diagnosing 915 pregnancies. All cows were re‐checked at 49–56 day after artificial insemination, and cows no longer pregnant were recorded as having suffered pregnancy loss. Although Vet‐A and Vet‐B diagnosed a similar proportion of pregnancies (58.44 ± 16% vs 56.96 ± 18%, p > .05), the rate of pregnancy loss was significantly higher among cows diagnosed by Vet‐B (10.41 ± 11.2% vs 4.87 ± 9.0, p = .029). In addition, among cows diagnosed by Vet‐B, the rate of pregnancy loss was significantly higher among cows diagnosed, while he had fewer than 12 months’ PD‐US experience (11.17 ± 12.14%) than among cows that he diagnosed later (7.14 ± 11.01%, p = .038); in fact, this latter loss rate was comparable to that among cows diagnosed by Vet‐A during the same period (3.51 ± 9.83%, p = .620). These results suggest that inexperience with PD‐US during the late embryonic period can increase risk of early pregnancy loss, supporting the need for proper training.     

An Improved Gravimetric Method to Determine Total Petroleum Hydrocarbons in Contaminated Soils

A gravimetric method to determine heavy fractions of total petroleum hydrocarbons (TPH) in soils is reported. The method was adapted and calibrated by modifying previous standard methods published, incorporating energy and cost savings where possible. Artificially contaminated soils with different organic matter content, and aged in stationary mode for a period of 8 months were used for calibration. Insufficient solvent evaporation was identified as the most prevalent and largest positive interference in the gravimetric detection. To overcome this, while minimizing the need for heating, a combination of three 10-min rotary evaporator steps and 30 min of vacuum in a desiccator were applied, for a total solvent volume of 60 ml. Hexane was chosen as the extraction solvent and a 40–60 min treatment in an ultrasound bath of 260 W was found suitable to extract 80–95% of TPH extracted by the Soxhlet method. Finally, the use of silica gel for cleanup of co-extracted natural organic matter was found unnecessary, because of the low amounts co-extracted for soils with up to 5% organic carbon, and because the chemical nature of the co-extracted organic matter prevents its selective adsorption to silica.     

Th1 and Th2 indices of the immune response in pigs vaccinated against Taenia solium cysticercosis suggest various host immune strategies against the parasite

Kinetics of the production of serum antibody levels and Th1 (IL-2, IFN-gamma) and Th2 (IL-4, IL-10) cytokines was studied in five pigs vaccinated with a synthetic tri-peptide vaccine (S3Pvac) against Taenia solium, a vaccine that has been shown protects pigs against naturally acquired infection. Healthy pigs of mixed genetic background, similar to those bred in rural villages of Mexico, were vaccinated with S3Pvac or with adjuvant alone, kept in sanitary conditions and bled at different times after vaccination to study the development of their specific immune response. Peripheral blood mononuclear cells (PBMCs) of vaccinated pigs showed a significant increment in the production of Th1 cytokines (IL-2 and IFN-gamma) but not of Th2 cytokines (IL-4 and IL-10) after specific PBLs stimulation with all the individual peptides. A Th1-inclined cytokine profile leading to an exacerbated local inflammation at the early installation stage of the cysticercus may possibly interfere with their successful establishment in the serum antibodies against total cysticercus antigens and against each of the three different peptides comprising S3Pvac were detected 7-51 days after vaccination. Antibodies against GK-1 interfered with the cysticerci development into intestinal tapeworms in prednisolone-treated hamsters. The sub-lethal crippling effect of anti-GK-1 antibodies upon cysticerci indicates to a therapeutic application of S3Pvac in infected pigs having potential epidemiological consequences, as it could aid in decreasing the number of tapeworms expected to develop from the few cysticerci that survive in the vaccinated pigs.     

Nutritional evaluation of waste date fruit as partial substitute for soybean meal in practical diets of juvenile Nile tilapia, Oreochromis niloticus L.

The potential of waste date meal (WDM; low-quality date palm, Phoenix dactylifera L.) as a carbohydrate source in formulated diets for Nile tilapia was evaluated. Four isocaloric-practical diets (15.7 kJ g⁻¹) were formulated incorporating WDM at 0, 100, 200 and 300 g kg⁻¹ levels as partial substitutes for soybean meal (SBM). These were designated D₀ [284 g crude protein (CP) and 383 g carbohydrate (CHO) kg⁻¹ diet], D₁ (279 g CP and 446 g CHO kg⁻¹ diet), D₂ (207 g CP and 495 g CHO kg⁻¹ diet) and D₃ (175 g CP and 578 g CHO kg⁻¹ diet). Each diet was fed to three replicate groups of 30 fish [20.20 ± 0.09 g (±SE)] for 75 days. No feed-related mortality was observed during the entire experimental period. Final body weight (FBW) and specific growth rate (SGR) in the different treatments were statistically not significantly different ( P  > 0.05). Protein efficiency rate (PER) was lowest in diet D₀ and increased with decrease of SBM content (D₁–D₃). A significant increase in whole body lipid content was recorded in fish fed diets D₂ and D₃. Results showed that WDM could be a substitute for SBM up to 300 g kg⁻¹ in practical Nile tilapia diets without compromising growth.     

Fixed versus variable bulk canopy resistance for reference evapotranspiration estimation using the Penman–Monteith equation under semiarid conditions

In this paper, daily ET₀ estimates at two semiarid locations, Zaragoza and Córdoba, were obtained from the Penman–Monteith equation using either fixed (70 s m⁻¹) or variable r_c values. Variable r_c values were computed with two models, Katerji and Perrier, and Todorovic. Daily ET₀ estimates were computed from 24-h meteorological averages or from the sum of hourly estimates. Daily ET₀ measured values were obtained from a weighing lysimeter (Zaragoza) and an eddy covariance system (Córdoba). There was a good agreement at both locations between estimated and measured ET₀ values using a fixed r_c value and 24-h meteorological averages. Estimates obtained from the sum of hourly estimates were somewhat worse. When 24-h meteorological averages were used, the Katerji and Perrier model for variable r_c slightly improved ET₀ estimates at both locations. But that improvement does not support the effort to locally calibrate that model. When daily ET₀ estimates were obtained from the sum of hourly estimates, the Todorovic model improved the estimation at Zaragoza and, at a lesser degree, at Córdoba. Under the semiarid conditions of the two studied locations, the use of the Todorovic model is recommended to get hourly ET₀ estimates from which daily estimates can be obtained. If 24-h meteorological averages are used, a fixed r_c value as proposed by Allen et al. [Crop evapotranspiration: guidelines for computing crop water requirements, FAO Irrigation and Drainage Paper No. 56, FAO, Rome, 1998] should be enough for accurate ET₀ estimates.     

The In Vitro Secretion of Acetylcholinesterase by Adult Stages of Heligmosomoides polygyrus: the Effects of Broad‐Spectrum Anthelmintics

The secretion of acetylcholinesterase (AChE) by female and male Heligmosomoides polygyrus was studied in different in vitro culture media. AChE secretion was increased in the presence of fetal calf serum or bovine serum albumin (BSA). In the absence of crowding effects, specific AChE activity in excretion/secretion products was higher for male (2.41 ± 0.07 µmol min^?1 l^?1 mg^?1) than for female (0.56 ± 0.04 µmol min^?1 mg^?1) worms but on a per nematode basis both sexes showed comparable rates of secretion. Acetylthiocholine iodide was the favoured substrate of the enzyme. When the nematodes were incubated in vitro with albendazole (ABZ), ricobendazole (RBZ), mebendazole (MBZ), levamisole (LVM), morantel (MRT) or ivermectin (IVM), at concentrations from 1 mM to 10 nM, in RPMI medium for 2 or 6 h and then transferred to a drug‐free medium (RPMI medium supplemented with 0.5 % BSA) for 24 h or continuously exposed to the drugs in supplement‐free medium (24 h), the concentration‐ and time‐dependent inhibitory effects on AChE secretion were observed. The continued exposure to the drugs for all incubation periods (with a single exception for LVM 1 mM) produced the highest levels of inhibition. Under these conditions, the concentrations inhibiting the secretion of AChE by 50 % (IC₅₀) relative to drug‐free controls were estimated. The IC₅₀ values ranged from 0.012 µM (IVM) to 2.96 µM (MRT). The potential of this bioassay for the selective primary evaluation of new compounds with broad‐spectrum anti‐nematodal activity is discussed.     

Social psychology predictors for the adoption of soil conservation measures in Central Chile

With low adoption rates of soil conservation measures (SCM) widespread, we examine determinants of current and potential future adoption in the ‘Secano Costero’ region of Central Chile. Randomly selected farmers (N = 140) spent an equivalent of 48 000 CLP/year (∼79 US$) on SCM. Contingent valuation of a hypothesized soil conservation programme revealed a willingness‐to‐pay of 30 610 CLP/year (∼50·4 US$) for future adoption. Social‐psychology variables from Protection Motivation Theory (PMT; response efficacy, perceived barriers) were used to predict current and potential future adoption. Current spending on SCM is influenced by perceptions of (1) erosion problem severity, (2) response efficacy of SCM, (3) farming problems and (4) barriers (lack of labour and draught animals). In addition, farm size and education were significant predictors. Willingness‐to‐pay for future adoption of SCM is influenced by farmer perception of (1) response efficacy of SCM, and (2) community support to the programme as well as farm size, age and gender. Our results suggest that formal psychometric scale development for social‐psychology predictors for the adoption of SCM, e.g. based on PMT, is a promising avenue for the analysis of soil conservation decisions. Copyright © 2011 John Wiley & Sons, Ltd.