Metal-catalyzed oxidation of a structured lipid model emulsion

The effects of temperature, time, metal, citric acid, and tocopherol contents on the oxidation stability of a model oil-in-water emulsion prepared with enzymatically synthesized menhaden oil-caprylic acid structured lipid were evaluated by response surface methodology. The emulsions were stabilized by whey protein isolate. Oxidation was monitored by measuring lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS). Cupric sulfate and ferrous sulfate were used to study the effect of metal concentration and type. A statistical model was developed to determine the relationships between all variables considered. The relationships differed depending on the type of metal catalyst used. For both metal types, the metal concentration had the highest positive effect on peroxide value. Citric acid had the highest negative effect on peroxide value for iron-containing emulsions, while tocopherol had the highest negative effects for copper-containing emulsions. Results from the TBARS test did not vary significantly enough to yield an acceptable model.     

Study of the role of the carbohydrate and protein moieties of soy soluble polysaccharides in their emulsifying properties

The objective of this work was to investigate the role played by the protein fraction of soy soluble polysaccharide (SSPS) during its adsorption at oil/water interfaces. SSPS was separated in a high (HMF; 310 kDa) and low (LMF; 20 kDa) molecular weight fraction by gel filtration. SSPS/HMF consisted of 91.6% carbohydrate and 2.2% protein and showed better emulsifying properties than those of the whole SSPS, whereas SSPS/LMF seemed to affect negatively the adsorption behavior of SSPS. SDS-PAGE of the protein fraction obtained from SSPS/HMF showed a molecular mass of 50 kDa, was composed predominantly of proline (23.1%) and glutamic acid (15.2%), and still contained 8.8% of neutral sugar and 5.3% of uronic acid. Results indicated that not all of the protein material present in SSPS contributes to SSPS functionality but that only the material associated with HMF aids in the adsorption of SSPS onto oil/water interfaces.     

Impact of soil pressure and compaction on tracheids in Norway spruce seedlings

We tested the effect of soil compaction on Norway spruce seedlings in terms of the size and theoretical volume flow rate of the tracheids. The results show that soil pressure limits growth in the diameter of the lumens of tracheids in all parts of seedlings studied. The tracheids of the roots with primary xylem had larger lumens than those of the roots and shoots with secondary xylem in both unloaded and loaded seedlings. This corresponds to the higher cumulative theoretical volume flow rate of the tracheids from roots with primary xylem than those from roots and shoots with secondary xylem. Although the volume flow rate of tracheids, according to the Hagen-Poiseuille law, was directly proportional to the quadratic power of the capillary diameter (tracheid lumen), the cumulative curve of the theoretical hydraulic volume flow rate was higher or relatively comparable in loaded seedlings. An explanation for these findings is that there were higher gradients of water potential values in roots and leaves in loaded seedlings because the lengths of the conductive pathways were 27% shorter than in unloaded seedlings. We hypothesise that trees have adapted to different stresses by shortening their conductive pathways to maintain a transpiration rate similar to that of non-stressed trees. These results concerning the impact of soil compaction on tracheid diameter and volume flow rate improve our understanding of the growth and functioning of different conifer organs and the mechanisms underlying the efficiency of water transport through the root xylem to the shoot.     

Characterisation, Availability, and Risk Assessment of the Metals in Sediment after Aging

The behavior of metals in sediments after their disposal to land has important implications for the environmental management. The sediment from the Carska Bara (Serbia) was polluted with adequate metal salts in order to reach severe contamination based on the pseudo-total metal content of Pb, Cd, Ni, Zn, Cu, and Cr according to the corresponding Dutch standards and Canadian guidelines. The toxicity and fate of the metal in sediment depend on its chemical form, and therefore, quantification of the different forms of a metal is more meaningful than the estimation of its total concentration. In this study, fractionation of metals in sediment has been investigated to determine its speciation and ecotoxic potential, as well as evaluation of metal potential toxicity based on the simultaneously extracted metals (SEMs) and acid volatile sulfides (AVSs) analysis at the beginning of the experiment and after 5?weeks of sediment aging. The investigations suggest that Cd, Pb, and Zn have a tendency to associate with labile fraction, the most mobile and most dangerous fraction for the environment. Risk assessment code revealed their high risk. Copper and chromium showed low to medium risk to the aquatic environment. Nickel showed no risk to the aquatic environment. This was the case at the beginning and after 5?weeks of aging. Aging yielded an increased mobility of all metals based on the increased proportion in mobile fractions. The ??[SEM _i ]/[AVS] ratio was found to be >1 both at the beginning and after 5?weeks of aging, with the ratio showing an increase with time. This ratio indicates the potential availability/toxicity and, according to the US EPA criteria, the samples belong to the group with probable negative effect. If particular metals are considered, only the ??[SEM _i ]/[AVS] ratio for zinc was >1 at the beginning. After 5?weeks, the ratio was >1 for zinc, lead, and copper. Comparison of the results of sequential extraction and the results of SEM and AVS analysis showed good agreement for lead and zinc.     

Effect of entomopathogenic nematodes on the plant-parasitic nematode Nacobbus aberrans

Nacobbus aberrans is a sedentary endoparasite nematode that forms galls in the roots of infected plants and produces important economic losses in some countries of the American continent. It has a wide host range, attacking mainly potato, tomato, sugar beet, and pepper crops. A reduction in the plant-parasitic nematode populations in the presence of entomopathogenic nematodes (EPNs) has been frequently reported. In the present work, the effect of the application of two native EPN isolates (Steinernema rarum and Heterorhabditis bacteriophora) on a N. aberrans population was evaluated in tomato plants under greenhouse conditions. Sixty days after inoculation, the number of galls and egg masses and the reproduction factor (RF) of N. aberrans were calculated. Of the variables analyzed, only the RF was significantly lower in both EPN treatments than in control. N. aberrans reproduction decreased by 57 and 53 % in plants inoculated with S. rarum and H. bacteriophora, respectively. These results showed that EPNs and their bacterial symbionts affected the reproductive potential of the N. aberrans population. This is the first study addressing the use of EPNs in the control of this important plant-parasitic nematode.     

Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain

The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors.In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR = 3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR = 3), the youngest bovines (<2.5 years) and dairy cattle (Friesians).Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5–7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years.It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.     

Mycotoxin accumulation and corresponding ear rot rating in three maturity groups of European maize inoculated by two <Emphasis Type="Italic">Fusarium</Emphasis> species

Fusarium graminearum (FG) and F. verticillioides (FV) produce the mycotoxins deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FUM), respectively, in maize. The EU released limits for these toxins in food. Growing resistant varieties is one alternative to fulfill these limits. Quantification of mycotoxin concentrations is expensive and time consuming. If indirect selection based on cost efficient and fast ear rot rating is feasible, this could increase efficiency of selection. The objective of this study was to analyze correlations between mycotoxin concentrations and ear rot rating by inoculating three maturity groups (early, mid-late, late) each comprising about 50 inbred lines tested in Central and Southern Europe. In the early maturity group flint lines were more susceptible in all instances except ZEA than dent lines. Broad ranges and significant (P < 0.01) genotypic variances were detected, but also genotype × environment interaction variances were significant (P < 0.01). Heritabilities of ear rot rating were similar or higher than those of mycotoxin concentrations (0.61−0.93 and 0.56–0.89, respectively). Although high genotypic correlations between FUM and DON or ZEA were found (0.77; 0.76, respectively), separate testing of FV and FG and corresponding mycotoxins is necessary since genotypes resistant to FV were not necessarily resistant to FG and vice versa. Medium to high heritabilities and high genotypic correlations between ear rot and corresponding mycotoxin concentrations (0.87–0.99) suggest frequent identification of lines with reduced mycotoxin concentrations by ear rot rating. Assuming fixed budgets we conclude that indirect selection by applying cost efficient ear rot rating could increase selection intensity and therefore is more effective than direct selection for reduced mycotoxin concentrations.     

New biologically active compounds from Kenyan propolis

From propolis samples from Kenya, two new arylnaphtalene lignans were isolated, tetrahydrojusticidin B 1 and 6-methoxydiphyllin 2, along with four known phenolic compounds 5–8, found for the first time in propolis. The structures of the compounds were elucidated based on their spectral properties. The geranylstilbenes 7 and 8 demonstrated antibacterial activity against S. aureus, and the geranylflavon macarangin 6 possessed antiradical activity against DPPH radicals.     

Antiviral Activity of Carrageenans and Processing Implications

Carrageenan and carrageenan oligosaccharides are red seaweed sulfated carbohydrates with well-known antiviral properties, mainly through the blocking of the viral attachment stage. They also exhibit other interesting biological properties and can be used to prepare different drug delivery systems for controlled administration. The most active forms are λ-, ι-, and κ-carrageenans, the degree and sulfation position being determined in their properties. They can be obtained from sustainable worldwide available resources and the influence of manufacturing on composition, structure, and antiviral properties should be considered. This review presents a survey of the antiviral properties of carrageenan in relation to the processing conditions, particularly those assisted by intensification technologies during the extraction stage, and discusses the possibility of further chemical modifications.