The evolution of glucose‐6P‐dehydrogenase and 6P‐gluconate‐dehydrogenase activities and the ortho‐diphenolic content of sunflower leaves cultivated under different boron treatments.

Both enzymatic activities increased under B‐deficient and B‐toxic treatments. The ortho‐diphenolic content did not change with B levels.

Our results suggest that the primary B action on the OPP pathway is at the first enzyme (glucose‐6P‐dehydrogenase) level and that the B effect on 6P‐gluconate‐dehydrogenase is secondary to this. The B action on the enzymatic activities seems not to be caused by any direct interaction with substrates, as B infiltration of B‐deficient culture “in vivo”; seems to result in long term effects on cell structures and/or processes not easily r

In this paper the glucose‐6P‐dehydrogenase and 6P‐gluconate ‐ dehydrogenase activities and ortho‐diphenolic content of hydroponically‐cultivated sunflower‐leaves with moderately deficient, normal and toxic B levels were measured. The change in these parameters during time was considered, together with the restoration of enzymatic activities by means of borate infiltration of deficient and normal leaves. The micronutrient content of the leaves was alsversible by B infiltration of leaves. The positive correlation found between the 6P‐gluconate‐dehydrogenase activity and the Zn content in leaves might be interpretable as and indirect B effect on that activity through modification of Zn content.     

Protein quality, antigenicity, and antioxidant activity of soy-based foodstuffs

Commercial soy-based foodstuffs, including beverages ( n = 15), cow's milk supplemented with soy isoflavones ( n = 1), snacks ( n = 1), and biscuits ( n = 2), were analyzed to find any link between alterations in protein quality, safety (antigenicity), functionality (antioxidant activity), and food processing. Protein content was analyzed by the Kjeldhal method and available lysine by OPA assay. Chromatographic (RP-HPLC) and electrophoretic (SDS-PAGE) protein profiles were obtained to monitor modifications in the structure of soy allergens. The antigenicity was estimated by immunoblotting against soy total antibodies. Total phenol content was measured by Folin-Ciocalteu, while peroxyl radical scavenging activity of the sample was determined by ORAC FL assay. Protein content did not differ of those declared by the producers. Lysine availability was higher in liquid soy beverages compared to that in other soy foodstuffs studied here. 7S and 11S soy allergens were detected by RP-HPLC and SDS-PAGE, respectively. Both data indicated changes in soy protein patterns due to processing of instant powdered soymilk, soy snacks, and biscuits. Immunoblotting assay showed modifications in the antigenic response of these foodstuffs based on soy, suggesting that their processing had altered the structure of soy allergens. RP-HPLC, SDS-PAGE, and immunoblotting resulted in adequate analytical approaches for detecting changes in protein structure due to processing and adulteration. Protein quality, antigenicity, and antioxidant activity of soy products can be affected as a function of the intensity of the thermal processing.     

Assessing the protective effect of vertically heterogeneous canopies against radiative frost: The case of quinoa on the Andean Altiplano

Night radiative frost is a highly limiting factor for agriculture in Andean highlands. Nevertheless, a diversity of crop species have been domesticated there, commonly showing high heterogeneity in plant growth at the field level. The possible protective effect of crop canopy heterogeneity against nocturnal radiative frost is examined using a dual approach, combining a field experiment and a simplified energy balance model at the leaf level. Leaf and air temperatures were registered over an entire quinoa crop cycle in the Andean highlands of Bolivia, comparing two cultivars: Blanca de Yanamuyu, a traditional landrace with high plant height heterogeneity, and Surumi, a more homogeneous selected variety. In both cultivars, inverted air density profiles during calm and clear nights result in air temperature changes up to 3 °C over 0.5 m height, with minimum air temperature concentrated at the upper part of the canopy. In these conditions, leaf temperature gradients of up to 2.6 °C m⁻¹ develop within the canopy of the traditional landrace, with minimum leaf temperature significantly higher (P < 0.001) in shaded plants of the landrace than in the selected cultivar. A dynamic model of leaf temperature based on canopy parameters and climatic records at screen level adequately simulates leaf temperature differences in the case of a vertically heterogeneous quinoa canopy. A sensitivity analysis of the model reveals that canopy height, leaf area index, and sky cloudiness have the most important influences on the development of the sheltering effect, while air temperature and air humidity play a minor role under typical radiative frost conditions. As for wind speed, its actual influence remains unclear due to experimental and modelling limitations at low wind speeds. The significance of these results is discussed in terms of the trade-off between stress adaptation and biomass productivity.     

Effects of a dairy product fortified with multiple micronutrients and omega-3 fatty acids on birth weight and gestation duration in pregnant Chilean women

OBJECTIVE: To test the hypothesis that maternal food fortification with omega-3 fatty acids and multiple micronutrients increases birth weight and gestation duration, as primary outcomes. DESIGN: Non-blinded, randomised controlled study. SETTING: Pregnant women received powdered milk during their health check-ups at 19 antenatal clinics and delivered at two maternity hospitals in Santiago, Chile. SUBJECT: Pregnant women were assigned to receive regular powdered milk (n = 477) or a milk product fortified with multiple micronutrients and omega-3 fatty acids (n = 495). RESULTS: Intention-to-treat analysis showed that mean birth weight was higher in the intervention group than in controls (65.4 g difference, 95% confidence interval (CI) 5-126 g; P = 0.03) and the incidence of very preterm birth (0.80 just for mean birth weight and birth length in the on-treatment analysis; birth length in that analysis had a difference of 0.57 cm (95% CI 0.19-0.96 cm; P = 0.003). CONCLUSIONS: The new intervention resulted in increased mean birth weight. Associations with gestation duration and most secondary outcomes need a larger sample size for confirmation.     

A COLORIMETRIC METHOD FOR THE MICRO-DETERMINATION OF 2,2, BIS(P-CHLOROPHENYL) 1,1,1 TRICHLORETHANE (DDT)

A colorimetric method for the micro-determination of 2,2 bis(p-chlorophenyl) 1,1,1 trichlorethane (DDT) is presented. The test is based on the discovery that when DDT is heated in an anhydrous pyridine solution containing xanthydrol and solid potassium hydroxide a red color develops, which under proper conditions is proportional to the amount of DDT present. The reaction is sensitive to as little as 10 gammas of DDT. It will detect small differences in concentration within the range of 10 to 200 gammas. The test is relatively simple and can be run in a comparatively short time.     

Feeding of yeast(Candida spp.) improves in vitro ruminal fermentation of fibrous substrates

In vitro gas production technique(IVGPT) was used with the objective of determining the inclusion effect of live cells of two strains of Candida yeast on in vitro ruminal fermentation of two fibrous substrates. In order to achieve this, two experiments were performed: A) using oat straw(Avena sativa) as substrate; B) using alfalfa hay(Medicabo sativa) as substrate, comparing the effect of two different strains of Candida genre, both isolated from the rumen, on the mentioned substrates. Levica 25(Candida tropicalis) yeast belongs to the culture collection of the Institute of Animal Science, Cuba, and Levazoot 15(Candida norvegensis) yeast is part of the collection of the Faculty of Zootechnology and Ecology of the Autonomous University of Chihuahua, Mexico. Both strains demonstrated their potential in activating the ruminal fermentation. They stimulated(P<0.0001) the ruminal fermentation of the substrates under study. However, the Levazoot strain stimulated the dry matter(DM) fermentation of alfalfa in 21.43%, more than Levica 25. It is concluded that there is an influence of yeast strain and diet on the rumen environment and, therefore, it is important to select the appropriate strain in every production condition.     

Effects of butyrate, avilamycin, and a plant extract combination on the intestinal equilibrium of early-weaned pigs

We evaluated the effects of 3 additives, sodium butyrate (AC), avilamycin (AB), and a combination of plant extracts (XT), on the productive performance and the intestinal environment of the early-weaned pig. The XT was a standardized mixture with 5% (wt/wt) carvacrol (from Origanum spp.), 3% cinnamaldehyde (from Cinnamonum spp.), and 2% capsicum oleoresin (from Capsicum annum). Pigs (n = 32) weaned at 18 to 22 d of age with an initial BW of 6.0 +/- 0.10 kg were allocated to 8 pens that, in turn, were allocated to 4 treatments. The treatments included a basal diet (CT) or the basal diet supplemented with 0.3% of AC, 0.04% of AB, or 0.03% of XT. Productive performance was determined during the initial 14 d postweaning. On d 19 and 21 of the experiment, the pigs were killed to allow collection of digesta and intestinal tissue to evaluate variables indicative of aspects of the gastrointestinal environment. Treatments AB and AC improved G:F (P = 0.012 and 0.003, respectively) compared with the CT. Butyrate included in the diet was only detected in the stomach but not in cranial jejunum. When compared with CT, AC produced a lower ileal starch digestibility (P = 0.002) and a lower whole-tract OM and starch digestibility (P = 0.001 and 0.003, respectively), related to a lower VFA concentration in the cranial colon (P = 0.082) and a numerically reduced branched VFA percentage in the rectum. The AB treatment diminished propionate production in caudal colon (P = 0.002) and rectum (P = 0.012) compared with CT. The AC group exhibited deeper crypt depth in the jejunum without variations in villus height compared with CT (P = 0.042). The AC and AB groups also increased goblet cell presence in the colon (P = 0.001 and 0.032, respectively). On the other hand, AB and XT diminished intraepithelial lymphocytes in the jejunum (P = 0.003 and 0.034, respectively). The XT increased lymphocyte presence in the colon (P = 0.003). These results show the important influence of AB and AC on productive performance and on pig gut dynamics. The intestinal modifications observed for AB and AC compared with CT suggest distinct modes of action for each additive.     

Development of a carbon-heat hybrid ethylene scrubber for fresh horticultural produce storage purposes

A scrubber to remove ethylene continuously from stored environments was developed. The device comprised a cartridge heater tightly joined to the activated carbon–1% Pd. The application of heat pulses led to an increase in ethylene oxidation and to auto-regeneration of the activated carbon. The efficacy of ethylene removal was higher with the number of heat pulses. Several combinations of exogenous ethylene concentrations and heater core temperatures (100–325 °C) of the device were assayed to determine their effectiveness in removing ethylene from the storage area. The results indicated that increasing the heater temperature led to enhanced percentages of eliminated ethylene but also increased CO₂ concentrations. This CO₂ could come from the activated carbon due to its breakthrough. Thus, temperatures ranging between 150 and 200 °C eliminated 96–99% of ethylene, with low CO₂ accumulation (0.10–0.18 kPa) and without affecting the temperature of the storage environment. Thus, this device might be a promising tool for scrubbing ethylene from storage areas for fresh horticultural produce in which ethylene can induce detrimental effects.     

In vitro antifungal activity of extracts of Mexican Chihuahuan Desert plants against postharvest fruit fungi

Chemical fungicides have been intensively used in the control of diseases in fruits in postharvest conditions; nevertheless these actions have developed resistance in the phytopathogens, have contaminated the atmosphere, and have affected people's health through residual toxic compounds present in the food for human consumption. The objective of this study was to evaluate the in vitro inhibiting activity of extracts of Lippia graveolens Kunth, Agave lechuguilla Torr. Yucca carnerosana (Trel.) Mc Kelvey and Yucca filifera Chaub., against Rhizopus stolonifer, Colletotricum gloesporoides and Penicillium digitatum the postharvest fungi that causes diseases in fruits of commercial interest. The plants were collected in the neighborhood of the cities of Saltillo and Torreon in the Southern Region of the State of Coahuila in the semi-arid zones of the North of Mexico. The extracts of the plants were obtained with ethanol and hexane as solvents, and the resin was separated of solvent in a rotary evaporator. The fungi were isolated of apple, mango and orange fruits and were then seeded in Potato-Dextrose-Agar medium; the bioassays were inoculated with fungi and developed in Petri dishes. The evaluated variables were: Inhibition of mycelial growth, and Inhibition of the number of spores. For the analysis of the information a completely randomized experimental design in factorial arrangement was used. The results showed that the ethanolic extracts of L. graveolens at 500 μl L⁻¹ presented a fungicide effect of 100% against R. stolonifer, Y. filifera at 4000 μl L⁻¹ inhibited 100% the pathogen. The hexanic extracts of L. graveolens presented an inhibition of 100% at 500 μl L⁻¹. A. lechuguilla inhibited the pathogen in 100% at 3000 μl L⁻¹. The extract of L. graveolens, A. lechugilla, Y. carnerosana and Y. filifera showed its inhibiting activity in different percentages against the development of R. stolonifer, Colletotrichum gloeosporioides, and P. digitatum. This is the first scientific report that shows anti-fungal activity of ethanolic and hexanic extracts of L. graveolens, A. lechuguilla, Y. carnerosana, and Y. filifera against R. stolonifer, C. gloesporoides, and P. digitatum.