Effect of drought on biomass, protein content, lipid peroxidation and antioxidant enzymes in two sesame cultivars

The effects of drought on growth, protein content, lipid peroxidation, superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and polyphenol oxidase (PPO) were studied in leaves and roots of Sesamum indicum L. cvs. Darab 14 and Yekta. Four weeks after sowing, plants were grown under soil moisture corresponding to 100, 75, 50 and 25 % field capacity for next four weeks. Fresh and dry masses, and total protein content in leaves and roots decreased obviously under drought. However, several new proteins appeared and content of some proteins was affected. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was lower in Yekta than in Darab 14. Severe stress increased SOD, POX, CAT and PPO activities in leaves and roots, especially in Yekta. According to the present study Yekta is more resistant to drought than Darab 14.     

First step towards the biomolecular characterization of Pompia,an endemic Citrus-like fruit from Sardinia (Italy)

This study is the first molecular and biochemical analysis conducted on Pompia, a plant of unknown origin that is endemic to Sardinia; this plant is thought to belong to the Citrus genus. Here, genes coding for the enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), and polyphenol oxidase (PPO, EC 1.14.18.1) were identified. We detected the aforementioned enzymes in fresh leaf tissue and assessed the catalytic activity of each to support the molecular and biochemical data. This was the first molecular study to define the primary structure of proteins with antioxidant activity in Pompia. The study also contributed to the enrichment of gene databases and created the basis for molecular phylogenetic studies, which is important because this plant currently has no taxonomic or phylogenetic classification.     

Temporal and ontogenetic aspects of protein induction in foliage of the tomato, Lycopersicon esculentum

Damage to foliage of the tomato, Lycopersicon esculentum, causes the induction of proteinase inhibitors and of the oxidative enzymes polyphenol oxidase, peroxidase, and lipoxygenase. The time courses of induction of these proteins by feeding of two caterpillar species (Manduca sexta and Helicoverpa zea) were studied in a series of experiments. In another series of experiments, the effects of plant age on the inducibility of these proteins were studied. In the time course experiments, induction of proteinase inhibitors and oxidative enzymes in the damaged leaflet was rapid, with higher protein activities evident in damaged leaflets within 12–24 h of damage, depending on the enzyme and the species of insect used to damage the plant. Systemic induction of proteinase inhibitors was also rapid, but systemic induction of polyphenol oxidase was delayed relative to systemic induction of proteinase inhibitors, possibly because high constitutive polyphenol oxidase activities obscured expression of systemic induction at earlier time points. Lipoxygenase and peroxidase were not induced systemically. Induction of all proteins persisted for at least 21 days. In the phenology experiments, inducibility of all proteins decreased in magnitude and was less consistent as plants aged. The results of these experiments exemplify the numerous constraints on induction in tomato plants. Knowledge of these physiological constraints is important to an understanding of the ecological role and causal basis of induced resistance.     

Plant growth regulator interactions results enhancement of antioxidant enzymes in Catharanthus roseus

Abstract

The present investigation was carried out with the objectives to understand the effect of paclobutrazol, gibberellic acid and Pseudomonas fluorescens on the enzymatic antioxidants like Ascorbate peroxidase (APX, EC: 1.11.1.11), Superoxide dismutase (SOD, EC: 1.15.1.1), Catalase (CAT, EC: 1.11.1.6), Peroxidase (POX, EC 1.11.1.7) and polyphenol oxidase (PPO, Ec 1.10.3.1) activities of Catharanthus roseus plants under field conditions. 10 mg l^?1 paclobutrazol, 5 µM gibberellic acid and 1 mg P. fluorescens concentrations were used for the treatments, and control plants were irrigated with well water. The treatments were given 38, 53, 68 and 83 days after planting (DAP) by soil drenching. The plants were taken randomly 45, 60, 75 and 90 DAP and separated into root, stem, leaves and flowers and used for estimating the antioxidant enzymes. The results showed that these plant growth regulators have significant effects on antioxidant enzymes of C. roseus.     

Effect of NaCl on biomass, protein and proline contents, and antioxidant enzymes in seedlings and calli of two Trigonella species

The effects of NaCl on growth, contents of proteins and proline, and activities of catalase, peroxidase and polyphenol oxidase were investigated in seedlings and calli of Trigonella foenum-graecum L. and T. aphanoneura Rech. f. Seeds and hypocotyl explants were cultured on Murashige and Skoog medium supplemented with 0, 50, 100, 150 and 200 mM NaCl. Seed germination and the fresh and dry mass of the seedlings decreased significantly under salinity. In both species significant increases in protein content of seedlings over that of control were observed at 150 and 200 mM NaCl. Protein content in calli decreased at 200 mM NaCl over that of control. Protein content was higher in seedlings than in calli at all NaCl concentrations. Conversely, proline content was lower in seedlings than in calli at all the tested NaCl concentrations. NaCl caused changes in the activities of peroxidase, catalase and polyphenol oxidase in seedlings and calli.     

Nucleotide sequence of katG of Salmonella typhimurium LT2 and characterization of its product, hydroperoxidase I

Summary The nucleotide sequence of katG from Salmonella typhimurium was determined revealing an open reading frame of 2181 by that could encode a 727 amino acid protein. The predicted sequence of the encoded hydroperoxidase I (HPI) was found to be 90% similar to HPI from Escherichia coli and was one amino acid longer. The physical and enzymatic properties of HPI from both Salmonella typhimurium and Escherichia coli were found to be virtually identical despite the 10% divergence in sequence.     

Phenolic oxidase activities in glandular trichomes of Solanum berthaultii

Polyphenol oxidase and peroxidase activities were detected in foliar glandular trichomes of the wild, insect-resistant potato species, Solanum berthaultii. These enzyme activities may provide the basis for conversion of clear, viscous trichome exudate into a hard, brown substance which is formed rapidly after insect attack.     

Purification and some properties of polyphenol oxidase from the yam tubers, Dioscorea bulbifera

In a comparison of the polyphenol oxidase activity of various species of yam tubers the greatest enzyme activity was found in D. bulbifera. The enzyme was purified from acetone powder extracts of this plant. Ammonium sulphate fractionation, followed by ion exchange chromatography and gel filtration gave 22-fold purification. The final product gave a single band on polyacrylamide disc gel electrophoresis. The purified enzyme showed activity towards catechol, pyrogallol and dl-β-3,4-dihydroxyphenylalanine (dl-DOPA) and had a MW 115000 ± 2000. It was characterized by response to various inhibitors. β-Mercaptoethanol, dithioerythritol, l-cysteine, sodium metabisulphite and KCN inhibited strongly.     

Influence of Ethephon and 2,5-Norbornadiene on Antioxidative Enzymes and Proline Content in Salt-Stressed Spinach Leaves

The effects of ethephon, an ethylene generating compound, and 2,5-norbornadiene (NBD), an inhibitor of ethylene action, on peroxidase (POD; EC 1.11.1.7), catalase (CAT; EC 1.11.1.6), polyphenol oxidase (PPO; EC 1.14.18.1) activities and proline content in salt-stressed spinach leaves were investigated. POD and PPO activities were increased by NaCl + ethephon + NBD combination and reduced by NBD. Also, ethephon increased the CAT activity while ethephon + NBD reduced CAT activity. NaCl + ethephon increased proline content. The antagonistic effect of ethephon and NBD was seen on POD and PPO activity and proline accumulation, but was not on CAT activity.     

Effects of limonene and essential oil from Citrus aurantium on gastric mucosa: Role of prostaglandins and gastric mucus secretion

Essential oil from Citrus aurantium and the monoterpene limonene are widely used flavoring agents that are found in some common food items. This specie is also used medicinally throughout the world to treat gastritis and gastric disorders. Therefore, biological assays were performed in vivo on essential oil of C. aurantium (OEC) and its majority compound limonene (LIM) to evaluate their effect on gastric mucosa. The OEC (250 mg/kg, p.o.) and LIM (245 mg/kg, p.o.) provided effective (99%) gastroprotection against lesions induced by absolute ethanol and NSAID (non-steroidal anti-inflammatory drug) in rats. OEC and LIM do not interfere with gastric H⁺ secretion, serum gastrin or glutathione (GSH) level in gastric mucosa. But the gastroprotective action of OEC and LIM occurs due to an increase in the gastric mucus production induced by conserving the basal PGE₂ levels after challenge by agents harmful to the gastric mucosa. Given that LIM and OEC are excellent flavoring agents and also present gastroprotective actions, they can be regarded as a promising target for the development of a new drug for the prevention of gastric damage.     

Chloroplasts and mitochondria have multiple heat tolerant isozymes of SOD and APX in leaf and inflorescence in Chenopodium album

Thermal stability of antioxidant defense enzymes superoxide dismutase (SOD, EC 1.15.1.1) and ascorbate peroxidase (APX, EC 1.11.1.11) was studied in chloroplasts and mitochondria of leaf and inflorescence in heat adaptive weed Chenopodium album. Leaf samples were taken in March (31 °C/14 °C) and young inflorescence (INF) was sampled at flowering in April (40 °C/21 °C). Leaf and INF chloroplast and mitochondrial fractions were subjected to elevated temperatures in vitro (5–100 °C) for 30′. SOD and APX showed activity even after boiling treatment in both chloroplast and mitochondria of leaf and INF. SOD was more heat stable than APX in both chloroplasts and mitochondria in both the tissues. Chloroplast contained more heat stable SOD and APX isozymes than mitochondria in both leaf and INF. To the best of our knowledge this is the first report showing presence of thermostable APX isozymes (100 °C for 30′) in chloroplasts and mitochondria in C. album. Heat stable isozymes of SOD and APX in chloroplasts and mitochondria in leaves and inflorescence may contribute to heat tolerance in C. album.     

Mutations in the mitochondrial split gene COXI are preferentially located in exons: a mapping study of 170 mutants

We have analysed the precise location of a large number (170) of mutations affecting the structural gene for subunit 1 of the cytochrome c oxidase complex. This gene, COXI, is 12.9 kb long and the major part of the sequence (i.e. 11.3 kb) is composed of introns. Several conclusions can be drawn from this study: (1) A significant proportion (84/170) of the mutations cannot be assigned to a single position within the gene by deletion mapping, in spite of clearly being located in it. These mutations are probably large deletions or multiple mutations. (2) Four mutants carry distant double mutations, which have been individually localized. (3) Eighty-two mutants have lesions that are restricted to very short regions of the gene and we therefore conclude that they are most probably due to single hits; amongst these single mutations, 41 are unambiguously located in exons and 28 in introns. This result implies that, at least in this particular split gene, the probability of selection of a mutant phenotype in an exon is, on the average, 13.3 times greater than in an intron, in spite of the existence, within most of these introns, of open reading frames specifying intronic proteins. The evolutionary significance and biological implications of these results are discussed.     

Cytogenetic analysis of chromosome region 89A of Drosophila melanogaster: isolation of deficiencies and mapping of Po, Aldox-1 and transposon insertions

Summary We have initiated a cytogenetic analysis of chromosome region 89A of Drosophila melanogaster by isolating a set of radiation-induced mutations causing loss of function of P[(w)B]1-1, a transposon bearing the white locus inserted in 89A. Complementation tests and cytological examination of these chromosomes identified four new deficiencies (Df(3R)Po ², Df(3R)Po ³, Df(3R)Po ⁴ and Df(3R)c(3)G ² ). The new deficiencies and three previously identified deficiencies (Df(3R)sbd ²⁶, Df(3R)sbd ⁴⁵ and Df(3R)sbd ¹⁰⁵) were tested for the ability to complement mutations in the enzyme loci Po and Aldox-1, the indirect flight muscle genes Tm2 and act88F, the morphological mutations jvl, sbd ² and Sb, the vital loci srp, pnr and mor, and a newly described vital locus l(3)89Aa. We also used linkage analysis to determine the order and relative positions of P[(w)B]1-1 and an independent transposon insertion, P[w⁺]21, with respect to cv-c, Po, Aldox-1 and sbd ². Cytological examination of the deficiencies and analysis of the transformed lines by in situ hybridization permits the correlation of genetically defined regions with specific polytene chromosome bands. A revised cytogenetic map of the 8817–8913 region is presented.     

Analysis of the Escherichia coli glycogen gene cluster suggests that catabolic enzymes are encoded among the biosynthetic genes

The nucleotide sequences of the Escherichia coli genome between the glycogen biosynthetic genes glgB and glgC, and 1170 bp of DNA which follows glgA have been determined. The region between glgB and glgC contains an open reading frame (ORF) of 1521 bp which we call glgX. This ORF is capable of coding for an M_r 56 684 protein. The deduced amino acid (aa) sequence for the putative product shows significant similarity to the E. coli glycogen branching enzyme, and to several different glucan hydrolases and transferases. The regions of sequence similarity include residues which have been reported to be involved in substrate binding and catalysis by taka-amylase. This suggests that the proposed product may catalyze hydrolysis or glycosyltransferase reactions. The cloned region which follows glgA contains an incomplete ORF (1149 bp), glgY, which appears to encode 383 aa of the N terminus of glycogen phosphorylase, based upon sequence similarity with the enzyme from rabbit muscle (47% identical aa residues) and with maltodextrin phosphorylase from E. coli (37% identical aa residues). Results suggest that neither ORF is required for glycogen biosynthesis. The localization of glycogen biosynthetic and degradative genes together in a cluster may facilitate the regulation of these systems in vivo.     

Essential leaf oil variability in green,variegated and albino foliage of Myrtus communis

Green, variegated and albino leaves of Myrtus communis yield mono- and sesqui-terpenes which show considerable variation in their ratios when compa     

Systematic studies of Pinus balfouriana based on volatile terpenoids from wood and needles and on seed morphology

Essential oil from wood and from needles of Pinus balfouriana, growing in six geographically well-separated locations in California, was analysed by GLC. Several monoterpenoid components, in particular -pinene from needles, were found to be usable for distinguishing between trees from the northern and southern parts of the geographic range. Similarity coefficients were calculated and dendrograms constructed. These demonstrated the distinct separation of the northern from the southern populations, and thus substantiated the proposal by Mastrogiuseppe to regard the southern populations as a subspecies. While the northern populations exhibited a tendency to produce larger seeds with longer wings, the difference was of only moderate diagnostic value.     

A chemotaxonomic study of Brassica oleracea with particular reference to its relationship to Brassica alboglabra

A chemotaxonomic study has been made of Brassica oleracea L., its horticultural varieties and Brassica alboglabra Bailey with reference to seed proteins, certain isoenzymes and isothcioyanates. The results of the investigation do not support separate species status in respect of B. alboglabra.     

A comparative disc electrophoretic study of pollen proteins of Betula populifolia

Pollen proteins of Betula populifolia Marsh. were separated by disc electrophoresis utilizing 7% acid and basic acrylamide gels. Significant variation in amounts of protein available for detection by disc electrophoresis were found. Statistical analysis of our data indicated that: length of storage periods do not affect acid and basic proteins equally; conformational changes in both acid and basic proteins occur with storage; significant migrations of both acid and basic proteins toward the cathode occur after storage.