[In silico analysis of Cit s 2: A highly conserved profilin]. / Análisis in silico de cit s 2: una profilina altamente conservada.

OBJECTIVE: Analyze phylogenetic relationships and molecular mimicry of Cit s 2 and other plant profilins. METHODS: Online bioinformatics tools including Basic Local Alignment Search Tool (BLASTP), PRALINE and MEGA were used for multiple alignments and phylogenetic analysis. A 3D-homology model of Cit s 2 was predicted. Models were calculated with MODELLER. The best model was selected with the model scoring option of MAESTRO. Conserved regions between Cit s 2 and other profilins were located on the 3D model and antigenic regions were predicted by ElliPro server (3-5). RESULTS: Cit s 2 amino acid sequence (Uniprot code:P84177) was compared with other 30 profilins from different allergenic sources. The identity between Cit s 2 and other profilins ranged between 82 and 99%. The highest identity was observed with Cucumis melo (99%) followed by Prunus persica (98%) and Malus domestica (92%). High conserved antigenic regions were observed on the 3D predicted model. Seven lineal and six discontinuous epitopes were found in Cit s 2. CONCLUSION: High conserved antigenic regions were observed on the 3D predicted model of Cit s 2, which might involve potential cross-reactivity between Cit s 2 and other profilins. Future studies are needed to further analyze these results.

OBJETIVO: Analizar las relaciones filogenéticas y el mimetismo molecular de Cit s 2 y otras profilinas vegetales. MÉTODOS: Se utilizaron herramientas bioinformáticas en línea, incluida la de búsqueda de alineación local básica (BLASTP), PRALINE y MEGA, para alineamientos múltiples y análisis filogenético. Se predijo un modelo de homología 3D de Cit s 2. Los modelos se calcularon con MODELLER. El mejor modelo fue seleccionado con la opción de puntuación de modelo de Maestro. Las regiones conservadas entre Cit s 2 y otras profilinas se ubicaron en el modelo 3D y las regiones antigénicas fueron predichas por el servidor ElliPro (3-5). RESULTADOS: La secuencia de aminoácidos de Cit s 2 (código Uniprot: P84177), se comparó con otras 30 profilinas de diferentes fuentes alergénicas. La mayor identidad se observó con Cucumis melo (99%) seguida de Prunus persica (98%) y Malus domestica (92%). Se observaron regiones antigénicas altamente conservadas en el modelo predicho en 3D. Se encontraron siete epítopes lineales, y seis epítopes discontinuos en Cit s 2. CONCLUSIÓN: Se observaron regiones antigénicas altamente conservadas en el modelo 3D predicho de Cit s 2, lo que podría implicar una posible reactividad cruzada entre Cit s 2 y otras profilinas. Se necesitan estudios futuros para analizar más a fondo estos resultados.

Molecular docking and anti-ulcerative potential of Cucumis (L. Inodorous) on ibuprofen induced gastric ulceration in male wistar animals.

BACKGROUND: The use of NSAIDs have caused stomach injury by inhibiting endogenous mucosal prostaglandin production. Cucumis melo is reported to possess antiulcer potential. This study investigates the mechanism underlying the antiulcer potentials of Cucumis melo (CUM). METHODS: Thirty-five male Wistar rat were randomly assigned to each of seven groups; A(control given water and rat pellets), B(gastric ulcer induced with ibuprofen 400 mg/kg), C (Misoprotol 200 µg/kg), D to G (pretreated with different variation of CUM extract; 25 %, 50 %, 75 % and 100 % at a dose of 1 ml/kg for 3 weeks prior to gastric ulcer induction). Ulcer score, ulcer index and percentage inhibition, total gastric acidity was measured. Antioxidant activities, Malondialdehyde, H+/K+ ATPase, PGE2, TNF-α was done by spectrophotometry. Molecular docking investigation of Cucumis melo compounds against Prostaglandin E2 was carried out. Level of significance was tested at P ≤ 0.05 using Tukey post hoc. RESULT: Total gastric acidity, ulcer score, ulcer index, MDA, TNF-α significantly decreased after CUM treatment when compared to group B. The percentage inhibition, antioxidant activities, PGE2 concentration was significantly increased in all treatment groups compared to group B. Interactions of selected compounds of CUM with Prostaglandin E2 at various docking pockets showed folic acid has highest binding affinity followed by delta7-avenasterol and codisterol to PGE2 receptor. this study shows that one of the mechanisms by which CUM exhibits its antiulcer potential by enhancing Prostaglandin synthesis and antioxidant capacity. Therefore, Cucumis melo can therefore be explored as novel antiulcer agents.

Global Profiling of lncRNAs Expression Responsive to Allopolyploidization in Cucumis.

Long non-coding RNAs (lncRNAs) play critical regulatory roles in various biological processes. However, the presence of lncRNAs and how they function in plant polyploidy are still largely unknown. Hence, we examined the profile of lncRNAs in a nascent allotetraploid Cucumis hytivus (S14), its diploid parents, and the F1 hybrid, to reveal the function of lncRNAs in plant-interspecific hybridization and whole genome duplication. Results showed that 2206 lncRNAs evenly transcribed from all 19 chromosomes were identified in C. hytivus, 44.6% of which were from intergenic regions. Based on the expression trend in allopolyploidization, we found that a high proportion of lncRNAs (94.6%) showed up-regulated expression to varying degrees following hybridization. However, few lncRNAs (33, 2.1%) were non-additively expressed after genome duplication, suggesting the significant effect of hybridization on lncRNAs, rather than genome duplication. Furthermore, 253 cis-regulated target genes were predicted for these differentially expressed lncRNAs in S14, which mainly participated in chloroplast biological regulation (e.g., chlorophyll synthesis and light harvesting system). Overall, this study provides new insight into the function of lncRNAs during the processes of hybridization and polyploidization in plant evolution.

Nitrogen Fertilization Increases the Nutritional Quality of Aphis gossypii (Hemiptera: Aphididae) as Prey for Hippodamia variegata (Coleoptera: Coccinellidae) and Alters Predator Foraging Behavior.

Nitrogen (N) fertilization is a common agricultural practice, which, by increasing the quality of plants, also enhances their nutritional suitability for insect herbivores, creating the possibility of a cascade of N across trophic levels, from plant to herbivore to predator. We manipulated the quality of cucumber plants by fertilizing them with three different N rates (110, 160, and 210 ppm), which represented low, medium, and high N levels, respectively. Colonies of Aphis gossypii Glover (Hemiptera: Aphididae) were then reared on these plants and used as prey for adult Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) in experiments that characterized the predator's foraging behavior and functional response to different aphid densities. The nutritional content of plants and aphids was also measured. As N fertilization increased, so did the nutrient content (total energy) of aphids and this resulted in declining rates of aphid consumption by beetles at higher aphid densities. Females in the 110 N treatment, and males in all treatments, responded to aphids with a type II functional response (decelerating consumption at higher densities), but females in the 160 and 210 ppm N treatments exhibited a type III response (consuming a declining proportion of available aphids at high densities). Beetles fed aphids from the 110 N treatment consumed more prey in both assays than did those fed aphids from the 210 N treatment. Beetle searching time, handling time, and duration of digestive pauses all increased at high levels of N fertilization, especially for females. The results indicate that heavy N fertilization can increase prey nutritional quality to the point where it alters predator foraging and feeding behavior, resulting in slower rates of prey consumption and longer prey handling times.

Effect of silver nanoparticles on phenolic compounds production and biological activities in hairy root cultures of Cucumis anguria.

The present study describes the elicitor effect of silver ion (Ag+) and biologically synthesized silver nanoparticles (AgNPs) to enhance the biomass accumulation and phenolic compound production as well as biological activities (antioxidant, antimicrobial and anticancer) in genetically transformed root (hairy root) cultures of Cucumis anguria. The biomass of hairy root cultures was significantly increased by AgNPs whereas decreased in Ag+ elicitation at 1 and 2 mg/L. AgNPs-elicited hairy roots produced a significantly higher amount of individual phenolic compounds (flavonols, hydroxycinnamic and hydroxybenzoic acids), total phenolic and flavonoid contents than Ag+-elicited hairy roots. Moreover, antioxidant, antimicrobial and anticancer activities were significantly higher following AgNPs-elicitation compared with that in Ag+-elicited hairy roots. We suggest that AgNPs could be an efficient elicitor in hairy root cultures to increase the phytochemical production.

Allopolyploidization in Cucumis contributes to delayed leaf maturation with repression of redundant homoeologous genes.

The important role of polyploidy in plant evolution is widely recognized. However, many questions remain to be explored to address how polyploidy affects the phenotype of the plant. To shed light on the phenotypic and molecular impacts of allopolyploidy, we investigated the leaf development of a synthesized allotetraploid (Cucumis × hytivus), with an emphasis on chlorophyll development. Delayed leaf maturation was identified in C. × hytivus, based on delayed leaf expansion, initial chlorophyll deficiency in the leaves and disordered sink-source transition. Anatomical observations also revealed disturbed chloroplast development in C. ×hytivus. The determination of chlorophyll biosynthesis intermediates suggested that the chlorophyll biosynthesis pathway of C. × hytivus is blocked at the site at which uroporphyrinogen III is catalysed to coproporphyrinogen III. Three chlorophyll biosynthesis-related genes, HEMA1, HEME2 and POR, were significantly repressed in C. × hytivus. Sequence alignment showed both synonymous and non-synonymous substitutions in the HEMA1, HEME2 and POR genes of the parents. Cloning of the chlorophyll biosynthetic genes suggested the retention of homoeologs. In addition, a chimeric clone of the HEMA1 gene that consisted of homologous genes from the parents was identified in C. × hytivus. Overall, our results showed that allopolyploidization in Cucumis has resulted in disturbed chloroplast development and reduced chlorophyll biosynthesis caused by the repressed expression of duplicated homologous genes, which further led to delayed leaf maturation in the allotetraploid, C. × hytivus. The preferential retention/loss of certain types of genes and non-reciprocal homoeologous recombination were also supported in the present study, which provides new insights into the impact of allopolyploidy.

Histopathology combined with transcriptome analyses reveals the mechanism of resistance to Meloidogyne incognita in Cucumis metuliferus.

Root-knot nematodes (Meloidogyne spp.) cause serious threat to cucumber production. Cucumis metuliferus, a relative of cucumber, is reported to be resistant to Meloidogyne incognita, yet the underlying resistance mechanism remains unclear. In this study, the response of resistant C. metuliferus accession PI482443 following nematode infection was studied in comparison with susceptible C. sativus cv. Jinlv No.3. Roots of selected Cucumis seedings were analysed using histological and biochemical techniques. Transcriptome changes of the resistance reaction were investigated by RNA-seq. The results showed that penetration and development of the nematode in resistant plants were reduced when compared to susceptible plants. Infection of a resistant genotype with M. incognita resulted in a hypersensitive reaction. The induction of phenylalanine ammonia lyase and peroxidase activities after infection was greater in resistant than susceptible roots. Several of the most relevant genes for phenylpropanoid biosynthesis, plant hormone signal transduction, and the plant-pathogen interaction pathway that are involved in resistance to the nematode were significantly altered. The resistance in C. metuliferus PI482443 to M. incognita was associated with reduced nematode penetration, retardation of nematode development, and hypersensitive necrosis. The expression of genes resulting in the deposition of lignin, toxic compounds synthesis, cell wall reinforcement, suppression of nematode feeding and resistance protein accumulation, and activation of several transcription factors might all contribute to the resistance response to the pest. These results may lead to a better understanding of the resistance mechanism and aid in the identification of potential targets resistant to pests for cucumber improvement.

Vascular-mediated signalling involved in early phosphate stress response in plants.

Depletion of finite global rock phosphate (Pi) reserves will impose major limitations on future agricultural productivity and food security. Hence, modern breeding programmes seek to develop Pi-efficient crops with sustainable yields under reduced Pi fertilizer inputs. In this regard, although the long-term responses of plants to Pi stress are well documented, the early signalling events have yet to be elucidated. Here, we show plant tissue-specific responses to early Pi stress at the transcription level and a predominant role of the plant vascular system in this process. Specifically, imposition of Pi stress induces rapid and major changes in the mRNA population in the phloem translocation stream, and grafting studies have revealed that many hundreds of phloem-mobile mRNAs are delivered to specific sink tissues. We propose that the shoot vascular system acts as the site of root-derived Pi stress perception, and the phloem serves to deliver a cascade of signals to various sinks, presumably to coordinate whole-plant Pi homeostasis.

Proteomics and metabolomics analyses reveal the cucurbit sieve tube system as a complex metabolic space.

The plant vascular system, and specifically the phloem, plays a pivotal role in allocation of fixed carbon to developing sink organs. Although the processes involved in loading and unloading of sugars and amino acids are well characterized, little information is available regarding the nature of other metabolites in the sieve tube system (STS) at specific sites along the pathway. Here, we elucidate spatial features of metabolite composition mapped with phloem enzymes along the cucurbit STS. Phloem sap (PS) was collected from the loading (source), unloading (apical sink region) and shoot-root junction regions of cucumber, watermelon and pumpkin. Our PS analyses revealed significant differences in the metabolic and proteomic profiles both along the source-sink pathway and between the STSs of these three cucurbits. In addition, metabolite profiles established for PS and vascular tissue indicated the presence of distinct compositions, consistent with the operation of the STS as a unique symplasmic domain. In this regard, at various locations along the STS we could map metabolites and their related enzymes to specific metabolic pathways. These findings are discussed with regard to the function of the STS as a unique and highly complex metabolic space within the plant vascular system.

Application of γ-aminobutyric acid demonstrates a protective role of polyamine and GABA metabolism in muskmelon seedlings under Ca(NO3)2 stress.

The effects of exogenous γ-aminobutyric acid (GABA) application on growth, polyamine and endogenous GABA metabolism in muskmelon leaves and roots were measured. Plants were treated under control or 80 mM Ca(NO3)2 stress conditions with or without foliar spraying 50 mM GABA. Ca(NO3)2 stress significantly suppressed seedling growth and GABA transaminase activity, and enhanced glutamate decarboxylase (GAD) activity and endogenous GABA levels. Polyamine (PA) biosynthesis and degradation capacity increased in parallel with increasing GAD activity. Exogenous GABA application effectively alleviated the growth inhibition caused by Ca(NO3)2 stress, and significantly enhanced the activities of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), polyamine oxidase (PAO), and diamine oxidase (DAO). Exogenous GABA also significantly reduced the accumulation of free putrescine (Put) and increased the levels of free spermidine (Spd) and spermine (Spm) in leaves, which improved the capacity for polyamine biosynthesis. Application of exogenous GABA under Ca(NO3)2 stress enables the plants to maintain a higher ratio of free Spd and free Spm with respect to free Put. Our data suggest that exogenous GABA has an important role in improving muskmelon seedling tolerance to Ca(NO3)2 stress by improving biosynthesis of PAs and GABA, and by preventing PA degradation. There is a potential positive feedback mechanism that results from higher endogenous GABA content and the combined effects of Ca(NO3)2 stress and exogenous GABA, which coordinately alleviate Ca(NO3)2 stress injury by enhancing PA biosynthesis and converting free Put to an insoluble bound PA form, and reduce PA degradation in muskmelon seedlings.

The effects of sewage sludge and sewage sludge biochar on PAHs and potentially toxic element bioaccumulation in Cucumis sativa L.

The presence of contaminants such as polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs), including As, Cd, Cu, Pb and Zn, restricts the application of sewage sludge (SS) to agricultural land. This research established that the conversion of SS to SS biochar (SSBC) significantly (p ≤ 0.01) decreased PAH and available PTE concentrations. Once added to soil both SS and SSBC significantly (p ≤ 0.05) decrease PAH availability. Bioaccumulation of PAHs into Cucumis sativa L. was reduced by both SSBC (44-57%) and (to a lesser extent 20-36%) by SS. Following addition to soil SSBC significantly (p ≤ 0.05) reduced available PTEs (except Cd), while SS significantly (p ≤ 0.05) increased PTE availability. As a consequence SSBC significantly (p ≤ 0.05) reduced PTE bioaccumulation (except Cd and Zn), while SS increased PTE bioaccumulation. These results suggest SSBC to be a candidate for soil amendment that offers advantages over SS in terms of PAH/PTE bioaccumulation mitigation.

Production of human tissue plasminogen activator (tPA) in Cucumis sativus.

Tissue plasminogen activator (tPA) as a serine protease with 72 kD molecular mass and 527 amino acids plays an important role in the fibrinolytic system and the dissolution of fibrin clots in human body. The collective production of this drug in plants such as cucumber, one of the most important vegetables in the world, could reduce its production costs. In this study, after scrutiny of the appropriate regeneration of cucumber plant (Isfahan variety) on MS medium with naphthalene acetic acid hormone (NAA; 0/1 mg L⁻¹) and benzyl amino purine hormone (BAP; 3 mg L⁻¹) hormones, the cloned human tPA gene under the CaMV 35S promoter and NOS terminator into pBI121 plasmid was transferred into cotyledon explants by Agrobacterium tumefaciens strain LBA4404. Subsequent to the regeneration of inoculated explants on the selective medium, the persistence of tPA gene in recombinant plants was confirmed by polymerase chain reaction (PCR) with specific primers. To evaluate the tPA gene expression in transgenic plants, RNA was extracted and the tPA gene transcription was confirmed by reverse-transcription (RT) PCR. Followed the extraction of protein from the leaves of transgenic plants, the presence of tPA protein was confirmed by dot blot and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) analysis in order to survey the production of recombinant tPA protein. The enzyme-linked immunosorbent assay (ELISA) test was used for recombinant tPA protein level in transgenic cucumber plants. It was counted between 0.8 and 1%, and based on this, it was concluded that the presence of three expressions of regulatory factors (CaMV 35S, Kozak, NOS) and KDEL signal in the construct caused the increase of the tPA gene expression in cucumber plants.

Optimal copper supply is required for normal plant iron deficiency responses.

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity.

Enantioselective separation and transformation of metalaxyl and its major metabolite metalaxyl acid in tomato and cucumber.

Many studies have shown the enantioselective transformation of metalaxyl in soil and animals, but little is known about the enantioselective biotransformation of metalaxyl in plants. In this study, a sensitive and convenient chiral liquid chromatography-tandem mass spectrometry method was developed for simultaneous measurement of the enantiomers of metalaxyl and its major metabolite, metalaxyl acid, in tomato and cucumber. Separation was by reversed-phase chromatography on a Chiralcel OD-RH column under isocratic conditions using acetonitrile-water (60/40, v/v) as mobile phase. The proposed method was successfully applied to investigate the possible enantioselective transformation of metalaxyl as well as the formation of metalaxyl acid in tomato and cucumber. In both vegetables, the (-)-R-enantiomer was preferentially degraded, resulting in relative enrichment of the (+)-S-enantiomer. Furthermore, formation of the metalaxyl acid enantiomers was also shown to be enantioselective, with the R-metalaxyl acid formed at a faster rate. This is the first evidence of enantioselective transformation of metalaxyl in vegetables, and the results should be considered in future environmental risk and food safety evaluations.

Proteomics reveal cucumber Spd-responses under normal condition and salt stress.

To investigate the effects of exogenous Spd on proteomic changes under normal condition and NaCl stress of 3 days in cucumber seedling leaves, a 2-DE gel electrophoresis and MALDI-TOF/TOF MS was performed. A total of 63 differentially expressed proteins responded to salt stress or exogenous Spd treatments, and they were all successfully identified by MALDI-TOF/TOF MS. Many changes were observed in the levels of proteins involved in energy and metabolic pathways, protein metabolic, stress defense, and other functional proteins. Increased salt tolerance by exogenous Spd would contribute to higher expressions of proteins involved in the SAMs metabolism, protein biosynthesis, and defense mechanisms on antioxidant and detoxification. Meanwhile, the regulation of Calvin cycle, protein folding assembly and the inhibition of protein proteolysis by Spd might play important roles in salt tolerance. This study provides insight that may facilitate a better understanding of the salt resistance by Spd in cucumber seedlings.

The role of abscisic acid in regulating cucumber fruit development and ripening and its transcriptional regulation.

Cucumber (Cucumis sativus L.), a kind of fruit usually harvested at the immature green stage, belongs to non-climacteric fruit. To investigate the contribution of abscisic acid (ABA) to cucumber fruit development and ripening, variation in ABA level was investigated and a peak in ABA level was found in pulp before fruit get fully ripe. To clarify this point further, exogenous ABA was applied to cucumber fruits at two different development stages. Results showed that ABA application at the turning stage promotes cucumber fruit ripening, while application at the immature green stage had inconspicuous effects. In addition, with the purpose of understanding the transcriptional regulation of ABA, two partial cDNAs of CsNCED1 and CsNCED2 encoding 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthetic pathway; one partial cDNA of CsCYP707A1 for 8'-hydroxylase, a key enzyme in the oxidative catabolism of ABA and two partial cDNAs of CsBG1 and CsBG2 for ß-glucosidase (BG) that hydrolyzes ABA glucose ester (ABA-GE) to release active ABA were cloned from cucumber. The DNA and deduced amino acid sequences of these obtained genes respectively showed high similarities to their homologous genes in other plants. Real-time PCR analysis revealed that ABA content may be regulated by its biosynthesis (CsNCEDs), catabolism (CsCYP707A1) and reactivation genes (CsBGs) at the transcriptional level during cucumber fruit development and ripening, in response to ABA application, dehydration and pollination, among which CsNCED1, CsCYP707A1 and CsBG1 were highly expressed in pulp and may play more important roles in regulating ABA metabolism.

Effects of 24-epibrassinolide on nitrogen metabolism in cucumber seedlings under Ca(NO(3))(2) stress.

Ca(NO(3))(2) accumulation is a major factor that limits greenhouse production in China. The present investigation was carried out to study the effect of 24-epibrassinolide (EBL) on nitrogen metabolism (including contents of NO(3)(-), NH(4)(+) and amino acids and related enzymes activities) in cucumber seedlings (Cucumis sativus L. cv. Jinyou No. 4) under 80 mM Ca(NO(3))(2) stress. This study found that exogenous EBL significantly reduced the accumulation of NO(3)(-) and NH(4)(+) by Ca(NO(3))(2), and enhanced the inactivated enzymes activities involved in the nitrogen metabolism. In addition, EBL alleviated the inhibition of photosynthesis nitrogen-use efficiency by Ca(NO(3))(2). Increased total amino acids by EBL under stress increased the precursor of proteins biosynthesis, thus promoting the biosynthesis nitrogen containing compounds. The presence of Ca(NO(3))(2) increased polyamines level, which might result from the increased content of free putrescine that is harmful to plant growth. However, exogenous EBL induced a further increase in total polyamines. The increase is likely caused by the elevated contents of conjugated and bound forms of polyamines. In summary, exogenously EBL compensated for the damage/losses by Ca(NO(3))(2) stress to some extent through the regulation of nitrogen metabolism and metabolites.

Insights into salicylic acid responses in cucumber (Cucumis sativus L.) cotyledons based on a comparative proteomic analysis.

To investigate the response of cucumber seedlings to exogenous salicylic acid (SA) and gain a better understanding of SA action mechanism, we generated a proteomic profile of cucumber (Cucumis sativus L.) cotyledons treated with exogenous SA. Analysis of 1500 protein spots from each gel revealed 63 differentially expressed proteins, 59 of which were identified successfully. Of the identified proteins, 97% matched cucumber proteins using a whole cucumber protein database based on the newly completed genome established by our laboratory. The identified proteins were involved in various cellular responses and metabolic processes, including antioxidative reactions, cell defense, photosynthesis, carbohydrate metabolism, respiration and energy homeostasis, protein folding and biosynthesis. The two largest functional categories included proteins involved in antioxidative reactions (23.7%) and photosynthesis (18.6%). Furthermore, the SA-responsive protein interaction network revealed 13 key proteins, suggesting that the expression changes of these proteins could be critical for SA-induced resistance. An analysis of these changes suggested that SA-induced resistance and seedling growth might be regulated in part through pathways involving antioxidative reactions and photosynthesis.

Enantioselective residue dissipation of hexaconazole in cucumber (Cucumis sativus L.), head cabbage (Brassica oleracea L. var. caulorapa DC.), and soils.

In this study, the enantioselective dissipation behavior of hexaconazole was investigated in cucumber fruit, head cabbage, and two different types of agricultural soils. The dissipation kinetics was determined by reverse-phase liquid chromatography-tandem mass spectrometry on a cellulose tris (3-chloro-4-methylphenylcarbamate) chiral column. Dissipation rates of hexaconazole enantiomers followed first-order kinetics; the residues of (+)-enantiomer decreased more rapidly than (-)-enantiomer in cucumber and head cabbage, resulting in relative enrichment of the (-)-form, while the two enantiomers showed similar degradation rates in the tested soils. These results indicate substantial enantioselectivity in the residue dissipation of hexaconazole enantiomers in cucumber and head cabbage; however, nonenantioselective dissipation was observed in the tested soils.

Effect of chromium on accumulation and antioxidants in Cucumis utillissimus L.: response under enhanced bioavailability condition.

This study compares the accumulation of Cr(VI) and biochemical changes (total chlorophyll, carotenoid, protein, malondialdehyde (MDA) and cysteine contents) and roles of antioxidant enzymes (superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX)) in tolerance to metal induced stress in Cucumis utillissimus L. grown in Cr contaminated soil (CS) with garden soil (GS). Furthermore, Cr bioavailability was enhanced by ethylene diamine tetra-acetic acid (EDTA) addition to the soil to forecast the plant's accumulation pattern at elevated Cr environment. Accumulation of Cr in the leaves of the plant increased with increase in substrate metals concentration. It further increased with the addition of EDTA by 1437% and 487% in GS and CS, respectively at the highest treatment level. The lipid peroxidation increased proportionately with increase in Cr accumulation in the leaves. All the activity of antioxidant enzymes (SOD, GPX and APX) and the level of cysteine increased with dose dependant manner. SOD and cysteine were observed to be higher in the GS than in CS, but APX and GPX were found to be higher in CS than in GS. The increase in GPX and APX activities with the increase in Cr concentration could be assumed that these two enzymes have a major role in the defense mechanism towards stress induced by Cr in C. utillissimus.