Role of glucose in the maillard browning of maltose and glycine: a radiochemical approach

We followed the contribution of released glucose to the formation of melanoidins in the maltose-glycine reaction by adding (14)C glucose to the maltose-glycine mixture, after it already had undergone some reaction. This approach allowed us to confirm the turnover of glucose in this reaction and hence the role of glucose in forming melanoidins. A comparison of the total amount of glucose converted into the melanoidins with the total concentration of melanoidins formed from maltose and glycine showed that the concentration of melanoidins originating from the released glucose was relatively small in comparison to the total melanoidins concentration. Hence, the parallel glucose-glycine reaction is considered to be only a minor pathway in the formation of maltose-glycine melanoidins. The incorporation of glucose into the nondialyzable melanoidins in the maltose-glycine reaction was in excellent agreement with the amount estimated from a kinetic model for the reaction of maltose with glycine. The rate constants were estimated by nonlinear regression, via multiresponse modeling.     

Influence of stage of development in the efficiency of nitrogen fertilization on poplar

Poplar cuttings (Populus x euroamericana) were planted in pots and grown in a greenhouse for four months with drip irrigation. Two nitrogen (N) doses of 60 and 120 kg nitrate (N-NO₃^?) ha^?1 (labeling with ¹⁵N stable isotopes) were applied at one (time I), two (time II) and three months after of the plantation (time III). The aim of this study was to determine the N-fertilizer application method that resulted in optimal N-uptake by a short-rotation of poplar crop during first year of growth. Our data revealed that NUE (N use efficiency) was largest in the last part of the experiment. The larger development of those plants at this stage enabled the improved absorption and assimilation of N. Furthermore, ¹⁵N also revealed that supply of N at three months post-planting generated more biomass and increased the N reserves in the stem; a key factor for ensuring the optimum regrowth during the second year.     

Influence of Degree of Protein Aggregation on Mass Transport Through Wheat Gluten Membranes and Their Digestibility—An In Vitro Study

The influence of the network structure of wheat gluten on the barrier properties against enzymes was investigated in vitro. The changes in the network structure were introduced by different temperature treatments. The modifications were assessed with solubility studies of wheat gluten proteins in sodium dodecyl sulfate (SDS). The physical barrier properties of wheat gluten membranes were investigated with transport studies examining the transfer of a model protein with no enzymatic activity (BSA) through gluten membranes. The protein network was an effective barrier for BSA, although lightly cross‐linked films were mechanically instable. Membrane breaks occurred in function of the cross‐linking density (percentage of SDS‐insoluble proteins) after only 24 hr for lightly cross‐linked films (≈30% SDS‐insoluble proteins), while highly cross‐linked membranes (≈80% SDS‐insoluble protein) were tight up to more than 33 days. The digestion experiments of the gluten films with pepsin showed that the hydrolysis of wheat gluten films with >72% of SDS‐insoluble protein was significantly retarded. In conclusion, technological treatments to increase the cross‐linking density of gluten have the potential to slow the digestion of cereal‐based foodstuff and to reduce the degradation rate of composite biomaterials.     

Comparative study of the composition of melanoidins from glucose and maltose

The composition of melanoidins formed in the reactions of either glucose or maltose with glycine (70 degrees C, pH 5.5, [glucose] = [maltose] = [glycine] = 0.25 M) (MW > 3500) was investigated by microanalysis and the use of (14)C-labeled sugars and amino acid. The most reliable parameter obtained from microanalysis data is the C/N value, as it was calculated with no model assumption. The C/N value (7.6 +/- 0.2 for glucose and 10.5 +/- 0.2 for maltose) does not change with molecular weight (MW > 3500) as the polymers grow in size. A comparison between the radiochemically determined composition and that obtained from microanalysis suggests that the amino ketone, which is one of the products of Strecker degradation reaction, forms part of the of the melanoidin structure, together with the sugar-derived moiety and the Strecker aldehyde. Evidence is presented that glucose is formed at intermediate stages of the maltose-glycine reaction. The melanoidins are the result of the polymerization of glucose and intact, or substantially intact, maltose residues with glycine.     

Variability of phenotypic and morphological characteristics of some Lathyrus sativus L. and Lathyrus cicera L. accessions and nutritional traits of their seeds

The object of the study comprised 54 grass pea (Lathyrus sativus) accessions originating from Czech Republic, Hungary, Slovak Republic, Poland, Ukraine and Russia together with 18 red pea (Lathyrus cicera) accessions from Greece, Spain and Italy. The plants were grown under the same conditions in Poland. Some phenological and morphological traits of plants as well as some seed morphological properties and nutritive value were investigated. Lathyrus sativus seeds contained more protein (average 300?g vs. 255?g?kg^?1 dry matter (DM)), whereas the differences in the average contents of the other basic nutrients between both these species as well as between particular accessions were not substantial. Except for a low level of methionine, the protein of both species showed fairly high concentration of other exogenic amino acids (EAAI around 63–64%). Fat of both L. sativus and L. cicera seeds was found to contain a high level of polyunsaturated fatty acids (66.9 and 58.6%, respectively), mainly linoleic (57.4 and 47.2%, respectively). The researched L. sativus accessions had a quite low level of β-ODAP (733?mg with a range of 0.583–1.340?mg?kg^?1 DM). Slightly higher content of this ANF (1,168?mg with 911–1,349?mg?kg ^?1 DM) in L. cicera seeds was noted. Average tannin concentration in the L. sativus and L. cicera accessions reached 3.3 and 6.4?g?kg^?1 DM, respectively. Average content of this ANF in L. sativus significantly correlated with the colour of both, flowers and seeds; with generally, a darker colour associated with higher levels of tannins.     

The use of Verticillium dahliae and Diplodia scrobiculata to induce resistance in Pinus halepensis against Diplodia pinea infection

The pathogenic fungi Verticillium alboatrum and Diplodia scrobiculata were assayed for biological control of Diplodia pinea on Aleppo pine (Pinus halepensis) in Catalonia (north-eastern Spain). Young shoots were pre-treated with inoculations of either V. dahliae or D. scrobiculata, by placing colonized agar plugs on wounds made by removing a single needle fascicle. An inoculation with D. pinea was performed 15 days later. Two months after the shoot inoculations, the canker length on the stems was measured and the percentage of shoot dieback calculated. Verticillium dahliae and D. scrobiculata were found to significantly reduce the canker length of D. pinea (P < 0.05) when compared with positive controls. Diplodia pinea was slightly more sensitive to V. dahliae than to D. scrobiculata, but no significant differences (P > 0.05) were observed in the mean canker length between the two treatments. Trees pre-inoculated with V. dahliae resulted in 31.12% shoot dieback, while those pre-inoculated with D. scrobiculata resulted in 32.18% shoot dieback, compared with positive controls (42.85%).     

Studies on the development of a mating disruption system to control the tomato leafminer, Tuta absoluta Povolny (Lepidoptera: Gelechiidae)

BACKGROUND: The tomato leafminer (Tuta absoluta Povolny) has rapidly colonised the whole Mediterranean and South‐Atlantic coasts of Spain, and it has become a key problem in both outdoor and greenhouse crops. New control methods compatible with biological control are required, and mating disruption appears to be a perfect method in current agriculture, as it is an environmentally friendly and residue‐free technique. IPM packages tested have included the use of pheromones to detect populations, but there has not been much previous research on mating disruption of T. absoluta. In this work, pheromone doses varying from 10 to 40 g ha^?1, emitted at a constant rate over 4 months, were tested in greenhouses with different levels of containment in order to evaluate the efficacy of mating disruption on T. absoluta. RESULTS: Trials on containment level revealed that the flight of T. absoluta was satisfactorily disrupted with an initial pheromone dose of 30 g ha^?1, and levels of damage did not significantly differ from those in reference plots with insecticide treatments. Later efficacy trials confirmed previous experiences, and release studies showed that control of damage and flight disruption were taking place when releasing at least 85 mg pheromone per ha per day. CONCLUSION: Effective control using pheromone application against T. absoluta can be achieved, in greenhouses with high containment levels, for 4 months, with initial doses of 30 g ha^?1. Further research must be conducted in order to evaluate the prospect of outdoor application of mating disruption systems. Copyright © 2011 Society of Chemical Industry     

Changes in the herbicide sensitivity and competitive ability of Abutilon theophrasti over 28 years: Implications for hormesis and weed evolution

BACKGROUND

The potential of weed species to respond to selection forces affecting the evolution of weedy traits such as competitive ability is poorly understood. This research characterized evolutionary growth changes in a single Abutilon theophrasti Medik. population comparing multiple generations collected from 1988 to 2016. A competition study was performed to understand changes in competitive ability, and a herbicide dose–response study was carried out to assess changes in sensitivity to acetolactate synthase-inhibiting herbicides and glyphosate over time.

RESULTS

When grown in monoculture, A. theophrasti biomass production per plant increased steadily across year-lines while leaf number decreased. In replacement experiments, A. theophrasti plants from newer year-lines were more competitive and produced more biomass and leaf area than the oldest year-line. No clear differences in sensitivity to imazamox were observed among year-lines. However, starting in 1995, this A. theophrasti population exhibited a progressive increase in growth in response to a sublethal dose of glyphosate (52 g a.e. ha⁻¹), with the 2009 and 2016 year-lines having more than 50% higher biomass than the nontreated control.

CONCLUSION

This study demonstrates that weeds can rapidly evolve increased competitive ability. Furthermore, the results indicate the possibility of changes in glyphosate hormesis over time. These results highlight the importance of the role that rapid (i.e., subdecadal) evolution of growth traits might have on the sustainability of weed management strategies. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Characterization of residues in soybeans grown in soil treated with 1,3-dichloropropene soil fumigant

The metabolism of cis- and trans-1,3-dichloropropene (1,3-D) was studied in soybean plants grown in soil treated 24 days prior to planting with [U-¹⁴C]E- and Z-1,3-dichloropropene at 380 liters ha^?1. Isolation and identification of the ¹⁴C residue from soybean plants at 84 days (forage) and 176 days (mature) after application showed that no 1,3-dichloropropene or its putative metabolites, 3-chloroallyl alcohol and 3-chloroacrylic acid, could be detected in any of the tissues. The components of the ¹⁴C residue included major plant constituents (i.e. fatty acids, protein, pigments, organic acids, sucrose and other carbohydrates, and lignin).