Effect of elevated manganese on the ultraviolet‐ and blue light‐absorbing compounds of cucumber cotyledon and leaf tissues

The effect of manganese [Mn(II)] on the pigments of cucumber (Cucumis sativus L., cv Poinsett 76) leaf and cotyledon tissues was investigated. Tissue disks (7 mm) were exposed to increasing Mn(II) concentrations from 100 μM to 2.5 mM. Acetone (carotenoid‐rich fraction) and acidified methanol (flavonoid‐rich fraction) extracts were analyzed by high performance liquid chromatography. Although none of the Mn(II)‐treated tissues showed visible damage, Mn(II) at concentrations of 250 μM and above significantly reduced (60%) the ß‐carotene levels of light‐incubated leaf tissues. A major Mn(II)‐induced, UV‐absorbing compound was observed in methanol extracts of cotyledonary tissues exposed to Mn(II) in the dark. In leaf tissues, Mn(II) reduced the levels of certain UV‐absorbing compounds under both light conditions. These results demonstrate that excess leaf Mn(II) can rapidly impair isoprenoid metabolism, altering tissue carotenoid composition. Furthermore, Mn(II) may also modify phenylpropanoid metabolism, changing the tissue flavonoid composition. Both situations could sensitize plant tissues to oxidative stresses, particularly enhanced solar UV‐B radiation, and may reduce the nutritional quality of leafy vegetables.     

Bioavailability of β-cryptoxanthin in the presence of phytosterols: in vitro and in vivo studies

Bioactive compounds are used in the design and development of new food products with potential health benefits, although little is known regarding their bioavailability and interactions. This study assessed the stability, in vitro bioaccessibility, and human bioavailability of β-cryptoxanthin from β-cryptoxanthin-rich drinks with and without added phytosterols developed for this purpose. The developed drinks showed no difference in the content of β-cryptoxanthin, and they were stable over 6 months. In vitro, hydrolysis of β-cryptoxanthin esters and the amount of free β-cryptoxanthin at duodenal and micellar phases were similar regardless of the presence of phytosterols. In the human study, the daily intake provoked significant increments of β-cryptoxanthin in serum regardless of the type of the drink. In conclusion, in vitro and in vivo human studies have shown that the bioavailability of β-cryptoxanthin is not significantly affected by the presence of phytosterols when they are simultaneously supplied in a drink.     

Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef

Because beef food products are generally cooked prior to consumption, the behavior of chemicals in these cooked foods is important in estimating human exposure. The heat stability of the natural estrogen β-estradiol (β-E2) and its metabolites α-estradiol (α-E2), estrone (E1), and several catechol estrogens was examined in heated vegetable oil and aqueous solutions. The chemicals were also incorporated into regular and extra lean ground beef and subjected to cooking. E1 and E2 were stable in aqueous solutions at 100°C, whereas the catechol estrogens exhibited first-order decay curves with half-lives of 2-10 min. Their stability improved to the same level as the other test chemicals when an antioxidant was added to the solution, suggesting that their disappearance was due to oxidation rather than thermal degradation. E1 and E2 were also stable in heated vegetable oil (160-180°C), whereas catechol estrogen decreased 30-50% over the 2 h duration of the experiments. Chemical losses from cooked beef appear to be related to the fat content of the beef, with greater losses occurring in regular ground beef (25-30%), compared to extra lean ground beef (5-20%). This study shows that cooking reduces but does not eliminate the potential for dietary exposure to growth promoters in ground beef.     

Influences of ultra‐violet (UV)‐blue light radiation on the growth of cotton. I. Effect on iron nutrition and iron stress response

Cool white fluorescent (CWF) light reduces Fe³⁺ to Fe²⁺ while low pressure sodium (LPS) light does not. Cotton plants grown under CWF light are green, while those yrown under LPS light develop a chlorosis very similar to the chlorosis that develops when the plants are deficient in iron (Fe). It could be that CWF light (which has ultra violet) makes iron more available for plant use by maintaining more Fe²⁺ in the plant. Two of the factors commonly induced by Fe‐stress in dicotyledonous plants‐‐hydroyen ions and reductants released by the roots‐‐were measured as indicators of the Fe‐deficiency stress response mechanism in M8 cotton.

The plants were grown under LPS and CWF light in nutrient solutions containing either NO₃‐N or NH₄‐N as the source of nitrogen, and also in a fertilized alkaline soil. Leaf chlorophyll concentration varied significantly in plants grown under the two light sources as follows: CWF+Fe > LPS+Fe > CWF‐Fe ≥ LPS‐Fe. The leaf nitrate and root Fe concentrations were significantly greater and leaf Fe was generally lower in plants grown under LPS than CWF light. Hydrogen ions were extruded by Fe‐deficiency stressed roots grown under either LPS or CWF light, but “reductants”; were extruded only by the plants grown under CWF light. In tests demonstrating the ability of light to reduce Fe³⁺ to Fe²⁺ in solutions, enough ultra violet penetrated the chlorotic leaf of LPS yrown plants to reduce some Fe³⁺ in a beaker below, but no reduction was evident through a yreen CWF grown leaf.

The chlorosis that developed in these cotton plants appeared to be induced by a response to the source of liyht and not by the fertilizer added. It seems possible that ultra violet liyht could affect the reduction of Fe³⁺ to Fe²⁺ in leaves and thus control the availability of this iron to biological systems requiring iron in the plant.     

Effect of the substrate concentration and water activity on the yield and rate of the transfer reaction of β-galactosidase from Bacillus circulans

Prebiotic galactosyl oligosaccharides (GOS) are produced from lactose by the enzyme β-galactosidase. It is widely reported that the highest GOS levels are achieved when the initial lactose concentration is as high as possible; however, little evidence has been presented to explain this phenomenon. Using a system composed of the commercial β-galactosidase derived from Bacillus circulans known as Biolacta FN5, lactose and sucrose, the relative contribution of water activity, and substrate availability were assessed. Oligosaccharide levels did not appear to be affected by changes in water activity between 1.0 and 0.77 at a constant lactose concentration. The maximum oligosaccharide concentration increased at higher initial concentrations of lactose and sucrose, while initial reaction rates for transfer increased but remained constant for hydrolysis. This suggests that the high oligosaccharide levels achieved at the raised initial saccharide concentration are due to increases in reactions that form oligosaccharides rather than decreases in concurrent reactions, which degrade oligosaccharides. There were different effects from changing the initial concentration of lactose compared to sucrose, suggesting that the ability of lactose to act as a donor saccharide may be more important for increasing maximum oligosaccharide concentrations than the combined ability of both saccharides to act as galactosyl acceptors.     

Effect of exogenous γ-aminobutyric acid treatment on proline accumulation and chilling injury in peach fruit after long-term cold storage

The effect of exogenous γ-aminobutyric acid (GABA) on chilling injury of peach fruit was investigated. Freshly harvested peaches were treated with 1, 5, or 10 mM GABA at 20 °C for 10 min and then stored at 1 °C for up to 5 weeks. The results showed that all of the GABA treatments could reduce chilling injury of peach fruit with 5 mM being the most effective concentration. GABA treatment significantly enhanced the accumulation of endogenous GABA and proline, which resulted from the increased activities of glutamate decarboxylase, Δ(1)-pyrroline-5-carboxylate synthetase, and ornithine δ-aminotransferase and decreased proline dehydrogenase activity. Our results revealed that GABA treatment may be a useful technique to alleviate chilling injury in cold-stored peach fruit, and the reduction in chilling by GABA may be due to the induction of endogenous GABA and proline accumulation. These data are the first evidence that exogenous GABA induced chilling tolerance in postharvest horticultural products.     

Effect of Synergism and Antagonism between Metals on Toxicity in Soils

Synergism and antagonism of cadmium(Cd),copper (Cu) and selenium (Se) to biological toxicities in red soil,yellow brown soil and black soil were evaluated by MICROTOX method.The relation between forms of the tested metals in soil and the synergism or antagonism between them was also studied.Results showed that owing to the difference of soil chemical properties,toxicity of these metals in soils was different.In red soil with acid reaction and low in cation exchange capacity,antagonism occurred significantly between metals when they coexisted at high concentrations,while synergism occurred only under low concentrations.It is indicated that in red soil,toxicity of metals affected by synergism or antagonism depends on concentration of the metals present.For yellow brown soil and black soil with larger cation exchange capacity and lower exchangeable aluminium(Al),no toxicity of metals was observed even if metals were added to soil in high concentrations.Synergism and antagonism between Cd,Cu and Se were controlled by the forms of metals present.The amount of water-soluble metals was the most important factor in determining synergism and antagonism. In this paper,comparisons of synergism and antagkonism between metals in soils and in water solutions were made.There occurred the synergism of metal toxicity in water solutions when the concentration of coexisting metals was high.This is just opposite to the case in soils.     

Effect of High‐Molybdenum Compost on Soils and the Growth of Lettuce and Barley

A pot experiment evaluated the growth of lettuce (Lactuca sativa L.) and barley (Hordeum vulgar) and accumulation of molybdenum (Mo) in plants and soils following amendments of Mo compost (1.0 g kg^?1) to a Truro sandy loam. The treatments consisted of 0 (control), 12.5, 25, and 50% Mo compost by volume. The Mo compost did not affect dry‐matter yield (DMY) up to 25% compost, but DMY decreased at the 50% compost treatment. The 50% compost treatments increased the soil pH an average of 0.5 units and increased the nitric acid (HNO₃)–extractable Mo to 150 mg kg^?1 and diethylenetriaminepentaacetic acid (DTPA)–extractable Mo to 100 mg kg^?1 in the growth medium; the same treatment increased tissue Mo concentration to 569 and 478 mg kg^?1 in the lettuce and barley, respectively. Plants grown in the 25% compost produced about 55 mg kg^?1 of total Mo in the growth medium; this resulted in tissue Mo concentration of 348 mg kg^?1 in lettuce and 274 mg kg^?1 in barley without any phytotoxicity. Our results suggested that 55 mg Mo kg^?1 soil would be an appropriate limit for Mo loading of soil developed from compost additions, a value which is presently greater than the Canadian Council for Ministers of the Environment (CCME) Guidelines for the use of type B compost in Canada.     

Effect of nitrate concentration on hydroponially grown primocane‐fruiting red raspberries

Primocane‐fruiting red raspberry plants (Rubus idaeus L.) ‘Redwing’ were grown in six hydroponic solutions containing nitrogen (N) levels of 2.5, 5, 10, 15, 20, and 25 meq N per liter. Plant growth rates and final cane heights were similar in all treatments except for reduced growth in the 2.5 meq per liter treatment. Greatest leaf, stem, and root dry weight accumulation was found in the 10 meq per liter treatment. The greatest numbers of nodes, flowers, and inflorescences per cane were found in the 5, 20, and 10 meq per liter treatments, respectively. Solution N levels had no effect on time of flowering.     

Effect of dicyandiamide on the form and recovery of 15N‐labeled urea in the delayed flood soil system

Abstract

Dicyandiamide (DCD) is a nitrification inhibitor that has been proposed for use in drill‐seeded rice. Immobilization of fertilizer NH₄ ⁺‐N by soil microorganisms under aerobic conditions has been found to be significantly enhanced in the presence of a nitrification inhibitor. The objective of this laboratory study was to determine if DCD significantly delayed nitrification of urea‐derived N, and if this enhanced immobilization of the fertilizer N in the delayed‐flood soil system inherent to dry‐seeded rice culture. Nitrogen‐15‐labeled urea solution, with and without DCD (1: 9 w/w N basis), was applied to a Crowley silt loam (Typic Albaqualf) and the soil was incubated for 10 weeks in the laboratory. The soil was maintained under nonflooded conditions for the first four weeks and then a flood was applied and maintained for the remaining six weeks of incubation. The use of DCD significantly slowed the nitrification of the fertilizer N during the four weeks of nonflooded incubation to cause the (urea + DCD)‐amended soil to have a 2.5 times higher fertilizer‐derived exchangeable NH₄+‐N concentration by the end of the fourth week. However, the higher exchangeable NH₄+‐N concentration had no significant effect on the amount of fertilizer N immobilized during this period. Immobilization of the fertilizer N appeared to level off during the nonflood period about the second week after application. After flooding, immobilization of fertilizer N resumed and was much greater in the (urea + DCD)‐amended soil that had the much higher fertilizer‐derived exchangeable NH₄ ⁺‐N concentration. Immobilization of fertilizer N appeared to obtain a maximum in the urea‐amended soil (18%) about two weeks after flooding and for the (urea + DCD)‐amended soil (28%) about four weeks after flooding.     

Effect of nitrogen and phosphorus on ‘delicious’ apple trees grown in caliche soil in the greenhouse

Abstract

In a greenhouse study, mono‐ammonium phosphate applications to ‘Delicious’ (Oregon spur cv) apple trees, Malus domestica Borkh., improved a low‐vigor condition associated with a caliche soil. The moderate rate of mono‐ammonium phosphate (6 grams per tree) resulted in trees with greater shoot extension, leaf numbers, a higher percent leaf phosphorus, and less purple leaf margins or spots than other soil treatments or the control. By September, trees treated with the highest rate of mono‐ammonia phosphate (12 grams per tree) had the highest level of leaf phosphorus and significantly higher levels of leaf phosphorus than all forms of nitrogen‐only fertilizer (ammonium nitrate, ammonium sulfate, calcium nitrate, and urea). In most cases, applications of the nitrogen‐only fertilizers, reduced leaf phosphorus levels throughout the experiment.     

Effect of Submergence on Iron Transformation and Phosphorus Availability in Calcareous Soils

A thermostatic incubation experiment was carried out to estimate the effects of flooding periods,stalk application and P addition of Fe transformation and P availability in calcareous soils.Submergence increased amorphous Fe,especially in the case of stalk application.The newly formed amorphous Fe with a great surface area played an important role in Psorption;and submergence also stimulated the dissolution of inorganic P,thus increasing the availability of soil P in calcareous soils.Meanwhile,a part of soluble P was absorbed and fixed again on the surface of newly formed amorphous Fe,thus resulting in a decrease of P availability.Soil rapidly available P increased after 150-day incubation.There existed significantly negative correlations between soil amorphous Fe content and soil Fe-P and rapidly available P contents.Submerged conditions promoted the transformation of inorganic P added toward Fe-P in calcareous soils,especially in the case of stalk application.     

Effect of hydroxypropyl-β-cyclodextrin on diuron desorption and mineralisation in soils

Purpose

The herbicide diuron has the unfortunate property of being strongly adsorbed onto soil organic matter particles, and hence, is slowly degraded in the environment because of its reduced bioavailability. The aim of this work was to gain insight into the fate and behaviour of diuron in the soil–water system, and develop and test an environmentally friendly soil decontamination technique that could give rise to an enhancement of diuron mineralisation by sensitive soil endogenous microorganisms, by means of increasing the bioavailability of the pollutant employing cyclodextrin (CD) solutions what would represent an improvement from both economic and environmental standpoints.

Materials and methods

Selected soil colloidal components: montmorillonite, a synthetic humic acid and a synthetic acicular goethite, and two different soils were employed in this study to perform batch adsorption–desorption experiments. Desorption experiments were performed using a 0.01 M Ca(NO₃)₂ solution with and without hydroxypropyl-β-cyclodextrin (HPBCD) 50 mM. Assays to study the mineralisation of ¹⁴C-labelled diuron were performed in respirometers, into which 10 g of soil and 50 mL of mineral salts medium (MMK) were placed, obtaining a final concentration of 50 mg?kg^?1 and a radioactivity of approximately 900 Bq per flask.

Results and discussion

Humic acid could be clearly discerned as the major colloidal component responsible for adsorption. HPBCD was used in diuron desorption experiments from soil, showing a strong extracting power on its removal. The mineralisation of diuron in the presence and absence of HPBCD was tested in a soil managed with diuron for several years, involving therefore the presence of microorganisms that have some specificity for diuron. Natural soil attenuation for diuron was improved when a HPBCD solution was used in the presence of micronutrients as a bioavailability enhancer, obtaining 66 % of mineralisation in comparison to that obtained with only micronutrients addition (44 %).

Conclusions

The use of HPBCD solution at a very low concentration of only 10 times the diuron equimolar concentration in soil, acts as a bioavailability enhancer, accelerating the passage of the diuron-desorbing fraction from the soil particle surface to the soil solution, and hence, improving the accessibility of the microorganisms to the herbicide. Diuron mineralisation rate and the extent of its mineralisation were improved when the HPBCD solution was employed in the presence of micronutrients.     

Effect of isomorphic substitutions on the Mössbauer and magnetic parameters of goethite

The effect of the isomorphic substitutions in the goethite structure on its magnetic and Mössbauer parameters was studied. For this purpose, synthetic samples of Al-substituted goethite with particle sizes of 24–28 nm were obtained and studied by means of Mössbauer spectroscopy, X-ray diffractometry, electron microscopy, and magnetic measurements. It was found that an increase in the number of isomorphic ions in the structure of this iron hydroxide reduces its susceptibility, magnetization, and the effective magnetic field of the nucleus. In addition, the structural substitutions of aluminum for iron ions leads to a significant decrease in the temperature of the magnetic phase transition (the Neel temperature). The way to explain the experimental results on the basis of the Neel theory in the nearest-neighbor approximation was considered. The possibility to use the obtained results for studying the genesis of iron oxides and hydroxides in soils was shown by the example of East African laterites.     

Effect of β-phenylethyl isothiocyanate from cruciferous vegetables on growth inhibition and apoptosis of cervical cancer cells through the induction of death receptors 4 and 5

Cruciferous vegetables have been shown to have the possibility to protect against multistep carcinogenesis. β-Phenylethyl isothiocyanate (PEITC) is one component of these vegetables demonstrated to help fight many types of cancer. The present study examined the apoptotic effects of PEITC and its molecular mechanism in human cervical cancer cell lines (HEp-2 and KB). PEITC induced apoptosis to inhibit cell proliferation. According to the protein chip assay, PEITC increased the expression of the death receptors (DR4 and DR5) and cleaved caspase-3 compared to the DMSO treatment group. PEITC also induced caspase-8 and truncated BID. PEITC down-regulated the phosphorylation of extracellular-related kinase (ERK)1/2, whereas neither phospho-c-Jun NH(2)-terminal kinases (JNK) nor phospho-p38 MAPK was changed. The role of ERK in PEITC-induced apoptosis was also investigated using MEK inhibitor (PD98059). PD98059 increased the expression of DR4 and DR5, activated caspase-3, and cleaved PARP. In addition, PEITC decreased the phosphorylation of MEK. Therefore, the apoptotic mechanism of PEITC in cervical cancer cells involves the induction of DR4 and DR5 through the inactivation of ERK and MEK.     

Effects of copper on the decomposition of plant residues,microbial biomass,and β-glucosidase activity in soils

Abstract

Two types of soils (Brown Lowland soil and Ando soil), which were artificially enriched with different amounts of Cu, were incubated with or without pulverized orchard grass for 12 weeks at 25°C. For both soils with and without orchard grass amendment, the amount of CO₂ evolved over the 12-week period of incubation decreased by the enrichment with Cu at a concentration exceeding 1,000 mg kg^?1 soil. The decrease of the mineralization of added orchard grass in the Cu-enriched soil was conspicuous especially during the initial period of incubation. The amount of microbial biomass C at the end of the incubation was significantly reduced by the Cu enrichment regardless of the amendment with orchard grass. The relative decrease of the soil microbial biomass was much greater than that of the soil respiration. The amount of biomass C was negatively correlated with the amount of 0.1 M CaCl₂-extractable Cu as a logarithmic function. On the other hand, the β-glucosidase activity at the end of the incubation was not significantly affected by the presence of Cu in the soils without orchard grass amendment and increased with the increase in the amount of enriched Cu in the orchard grass-amended soils.     

Effect of Salinity and Some Chemical Properties of the Under‐ and Intercanopy Soils on Range Plants in a Dry Region of Southern Iran

Abstract

The present study was conducted in a dry region in southern Iran to evaluate the effects of different Atriplex species on the salinity, soluble ions, and some of the other chemical properties of under‐ and intercanopy soils. The research region was divided into five separate sites with vegetation cover of the range plants Atriplex lentiformis, A. nummularia, and A. halimus (all newly introduced species) and A. leucoclada and Salsola rigida (both native species). Four 1‐kg soil samples (from under‐ and interspaces of the canopy of tested plants, each in two depths of 0–10 and 10–40 cm, were taken from each of the plant sites and analyzed for different determinations. The study was conducted as a factorial experiment in a complete random design with six replicates.

Regardless of distance and depth, different plant species resulted in different salinity (based on the EC values of saturation paste) and soluble cation contents in the tested soils. The results showed that the increase in EC values were associated with decreases in pH values of the tested soils.

The SAR values followed exactly the same pattern as EC values and Na⁺ concentrations. In the case of soluble anions, the Cl^? contents followed exactly the same pattern as the EC values of the tested soils, which indicates that the salts are predominantly chlorides of various cations (especially Na⁺). The OM and total nitrogen (N) contents of the undercanopy were greater than those of the interspace and those of the surface layer were greater than those of the sublayer. Moreover, although the phosphorus (P) and potassium (K) contents of undercanopy and interspace were not significantly different from each other, the P and K contents of the surface layer were greater than those of the subsurface layer. As seen from the results, except for the effect of depth of Mn contents and the interactive effect of distance and depth on Fe contents, neither the single effects (other than plant species) nor the interactive effects were significant on microminerals of the tested soils.

Moreover, copper (Cu) was particularly antagonistic toward iron (Fe), manganese (Mn), and zinc (Zn).     

Influences of ultra‐violet (UV)‐blue light radiation on the growth of cotton. II. Photosynthesis,leaf anatomy,and iron reduction

Cotton (Gossypium hirsutum L.) plants grown under low pressure sodium lamps (LPS) developed chlorosis which was similar in appearance to iron‐stress induced chlorosis, while plants under cool white fluorescent lamps (CWF) at the same level of photosynthetically active radiation (PAR) developed normally. These illumination sources differ in spectral irradiance; CWF lamps emit ultra violet (UV), whereas LPS lamps do not. Ultraviolet radiation is capable of reducing Fe³⁺ to Fe²⁺ through a chlorotic leaf which may be important in establishing an active iron fraction in the leaf. Root reduction of Fe³⁺ to Fe²⁺ was lacking in Fe‐stressed cotton under LPS light, but was present under CWF light. Net photosynthesis, photosynthetic electron transport, and leaf chlorophyll content were lower under LPS than CWF light in most of the growing media studies (soil or solutions with nitrate‐ or ammonium‐nitrogen supplied). Chloroplast ultrastructure and leaf thickness were also altered by LPS irradiance. Electron microscopic studies with plants grown in nutrient solutions for 4 weeks suggested that chioroplastic granal disorganization was more directly associated with diminished iron supplies than with light source. However, plants grown in soil for 6 weeks under LPS light had granal disorganization similar to that found in iron‐stressed plants. These studies suggest an important role for UV radiation in influencing the activity of iron in plants.