Assessment of salt tolerance of Nasturtium officinale R. Br. using physiological and biochemical parameters

Nasturtium officinale R. Br. seedlings were treated with a range of NaCl concentrations (0, 50, 100 and 150 mM) for 21 days after seedling emergence. Physiological analysis based on growth and mineral nutrition, showed a substantial decrease in leaf dry matter with 150 mM NaCl treatment. The growth decrease was correlated with nutritional imbalance and a reduction in potassium accumulation and transport to the leaves. At the same time, we noted an increase in leaf sodium and chloride accumulation and transport. Salt tolerance of N. officinale under 100 mM NaCl was associated with osmotic adjustment via Na⁺ and Cl^? and the maintenance of high K⁺/Na⁺ selectivity. Salt decreased carotenoid content more than chlorophylls and also disturbed membrane integrity by increasing malondialdehyde content and electrolyte leakage. At 150 mM NaCl, an increase in antioxidant enzyme-specific activities for superoxide dismutase, catalase and guaiacol peroxidase occurred in concert with a decrease in ascorbic acid, polyphenol, tannin and flavonoid content. These results indicate that N. officinale can maintain growth and natural antioxidant defense compounds such as, vitamin C, carotenoids, and polyphenols, when cultivated in 100 mM NaCl, but not at higher salt levels.     

Synthesis of 3-O-methylgallic acid a powerful antioxidant by electrochemical conversion of syringic acid

Background

A kinetic study of the electrochemical oxidation of syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) by cyclic voltammetry at treated gold disk was combined with results of electrolyses at Ta/PbO₂ anode in order to convert it into potentially high-added-value product.

Methods

The electrochemical oxidation of syringic acid was carried out in order to convert this compound to 3-O-methylgallic acid. This latter was identified by mass spectrophotometry using LC-MS/MS apparatus. The 3-O-methylgallic acid synthesis was controlled by cyclic volammetry, Ortho-diphenolicdeterminations and DPPH radical-scavenging activity.

Results

The proposed mechanism is based on the hypothesis of a bielectronic discharge of syringic acid molecule under free and adsorbed form involving two intermediate cation mesomers. Hydrolysis of the more stable of this last one leads to the formation of the 3,4-dihydroxy-5-methoxybenzoic acid (3-O-methylgallic acid) as a major product. The latter aromatic compound was synthesized by anodic oxidation of syringic acid at PbO2 electrode. The cyclic voltammogram of the electrolysis bath of syringic acid shows that the anodic peak potential of 3-O-methylgallic acid was lower (E_pa = 128 mV) than that of SA (E_pa = 320 mV). And the strongest antiradical activity was detected when the 3-O-methylgallic acid concentration was higher".

Conclusion

The electrochemical oxidation using PbO₂ anode is a rapid, simple and efficient method tool for a conversion of SA into 3-O-methylgallic acid, a potent antioxidant derivative

General Significance

The electrochemical process consists in a simple transformation of the syringic acid into 3-O-methylgallic acid having a better antioxidant capacity. This result has been justified by cyclic voltametry which shows that anodic peak of 3-O-methylgallic acid is reversible. Furthermore, its potential is lower than that of the irreversible anodic peak of syringic acid to 3-O-methylgallic acid.     

Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner–Hanhart Syndrome

Tyrosinemia type II, also designated as oculocutaneous tyrosinemia or Richner–Hanhart syndrome (RHS), is a very rare autosomal recessive disorder. In the present study, we report clinical features and molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in two young patients, both born to consanguineous unions between first-degree cousins. These two unrelated families originated from Northern and Southern Tunisia. The clinical diagnosis was based on the observation of several complications related to Richner–Hanhart syndrome: recurrent eye redness, tearing and burning pain, photophobia, bilateral pseudodendritic keratitis, an erythematous and painful focal palmo-plantar hyperkeratosis and a mild delay of mental development. The diagnosis was confirmed by biochemical analysis. Sequencing of the TAT gene revealed the presence of a previously reported missense mutation (c.452G > A, p.Cys151Tyr) in a Tunisian family, and a novel G duplication (c.869dupG, p.Trp291Leufs*6). Early diagnosis of RHS and protein-restricted diet are crucial to reduce the risk and the severity of long-term complications of hypertyrosinemia such as intellectual disability.     

Protective effect of the octadecaneuropeptide on hydrogen peroxide-induced oxidative stress and cell death in cultured rat astrocytes

Oxidative stress, resulting from accumulation of reactive oxygen species (ROS), plays a critical role on astrocyte death associated with neurodegenerative diseases. Astroglial cells produce endozepines, a family of biologically active peptides that have been implicated in cell protection. Thus, the purpose of the present study was to investigate the potential protective effect of one of the endozepines, the octadecaneuropeptide ODN, on hydrogen peroxide (H(2) O(2) )-induced oxidative stress and cell death in rat astrocytes. Incubation of cultured astrocytes with graded concentrations of H(2) O(2) for 1 h provoked a dose-dependent reduction of the number of living cells as evaluated by lactate dehydrogenase assay. The cytotoxic effect of H(2) O(2) was associated with morphological modifications that were characteristic of apoptotic cell death. H(2) O(2) -treated cells exhibited high level of ROS associated with a reduction of both superoxide dismutases (SOD) and catalase activities. Pre-treatment of astrocytes with low concentrations of ODN dose-dependently prevented cell death induced by H(2) O(2) . This effect was accompanied by a marked attenuation of ROS accumulation, reduction of mitochondrial membrane potential and activation of caspase 3 activity. ODN stimulated SOD and catalase activities in a concentration-dependent manner, and blocked H(2) O(2) -evoked inhibition of SOD and catalase activities. Blockers of SOD and catalase suppressed the effect of ODN on cell survival. Taken together, these data demonstrate for the first time that ODN is a potent protective agent that prevents oxidative stress-induced apoptotic cell death.     

Embryotoxicity and fetotoxicity following intraperitoneal administrations of hexavalent chromium to pregnant rats

Heavy metals are omnipresent in the environment, and industrial use has greatly increased their presence in soil, water and air. Their inevitable transfer to the human food chain remains an important environmental issue as many heavy metals cause a range of toxic effects, including developmental toxicity. Administration of chromium VI (1 and 2 mg/kg as potassium dichromate) through intraperitoneal (i.p.) injection during organogenesis (days 6 to 15 of gestation) in rats revealed embryo- and fetotoxic effects. Reduced fetal weight, retarded fetal development, number of fetuses per mother and high incidences of dead fetuses and resorptions in treated mothers were also observed. Gross morphological abnormalities, such as displayed form of edema, facial defect, lack of tail, hypotrophy, severs subdermal haemorrhage patches and hypotrophy of placenta were observed in fetuses after chromium VI-treated mothers. A skeletal development of fetuses presented an incomplete ossification in nasal, cranium, abdominal or caudal bones in rats treated with 1 mg/kg of chromium, whereas rats treated with 2 mg/kg showed ossification and absence of the sacral vertebrae compared with the control. At a higher dose of chromium, histological changes were found in fetuses with atrophy of theirs vital organs. Placental histological observations revealed a pronounced morphological alteration, with atrophy of decidual cells, a degenerated of chorionic villi and hypertrophy of blood lacuna. The present study suggests a risk to the developing embryo when the mother is exposed to a high concentration of chromium VI during organogenesis.     

Ten minutes of dynamic stretching is sufficient to potentiate vertical jump performance characteristics

The current literature recommends dynamic rather than static stretching for the athletic warm-up. Dynamic stretching and various conditioning stimuli are used to induce potentiation in subsequent athletic performance. However, it is unknown as to which type of activity in conjunction with dynamic stretching within a warm-up provides the optimal potentiation of vertical jump performance. It was the objective of the study to examine the possible potentiating effect of various types of conditioning stimuli with dynamic stretching. Twenty athletes participated in 6 protocols. All the experimental protocols included 10 minutes of dynamic stretching. After the dynamic stretching, the subjects performed a (a) concentric (DS/CON): 3 sets of 3 repetition maximum deadlift exercise; (b) isometric (DS/ISOM): 3 sets of 3-second maximum voluntary contraction back squats; (c) plyometric (DS/PLYO): 3 sets of 3 tuck jumps; (d) eccentric (DS/ECC): 3 modified drop jumps; (e) dynamic stretching only (DS), and (f) control protocol (CON). Before the intervention and at recovery periods of 15 seconds, 4, 8, 12, 16, and 20 minutes, the participants performed 1-2 maximal countermovement jumps. The DS and DS/CON protocols generally had a 95-99% likelihood of exceeding the smallest worthwhile change for vertical jump height, peak power, velocity and force. However, the addition of the deadlift to the DS did not augment the potentiating effect. Time-to-peak potentiation was variable between individuals but was most consistent between 3 and 5 minutes. Thus, the volume and the intensity associated with 10 minutes of dynamic stretching were sufficient to provide the potentiation of vertical jump characteristics. Additional conditioning activities may promote fatigue processes, which do not permit further potentiation.     

Alkaline proteases produced by <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> RP1 grown on shrimp wastes: Application in chitin extraction,chicken feather-degradation and as a dehairing agent

The current increase in the amount of shrimp wastes produced by the shrimp industry has led to the need in finding new methods for shrimp wastes disposal. In this study, Bacillus licheniformis RP1 was shown to produce proteases when grown in media containing shrimp wastes powder as a sole carbon and nitrogen source, indicating that this bacteria could obtain its carbon and nitrogen requirements directly from shrimp wastes. The maximum protease production was obtained when the strain was grown in a medium containing (g/L): shrimp wastes powder 30, KCl 1.5, K₂HPO₄ 0.5, and KH₂PO₄ 0.5. Using casein zymography, the crude protease preparation was found to produce at least seven proteases. The proteases of B. licheniformis RP1 were tested for shrimp waste deproteinization in the preparation of chitin. The percent of protein removal after 3 h hydrolysis at 60°C and at an enzyme/substrate (E/S) ratio of 0.5 and 5 (Unit of enzyme/mg of protein) were about 68 and 81%, respectively. Additionally, B. licheniformis RP1 showed important feather degrading activity. Complete solubilisation of whole feathers was observed after 24 h of incubation at 50°C. More interestingly, the RP1 proteolytic preparation demonstrated powerful dehairing capabilities for hair removal from skin. Collagen, which is the major leather-forming protein, was not significantly degraded. Considering its promising properties, B. licheniformis RP1 enzymatic preparation may be considered a potential candidate for future use in several biotechnological processes.     

The Octadecaneuropeptide ODN Protects Astrocytes against Hydrogen Peroxide-Induced Apoptosis via a PKA/MAPK-Dependent Mechanism

Astrocytes synthesize and release endozepines, a family of regulatory peptides, including the octadecaneuropeptide (ODN) an endogenous ligand of both central-type benzodiazepine (CBR) and metabotropic receptors. We have recently shown that ODN exerts a protective effect against hydrogen peroxide (H(2)O(2))-induced oxidative stress in astrocytes. The purpose of the present study was to determine the type of receptor and the transduction pathways involved in the protective effect of ODN in cultured rat astrocytes. We have first observed a protective activity of ODN at very low concentrations that was abrogated by the metabotropic ODN receptor antagonist cyclo(1-8)[DLeu(5)]OP, but not by the CBR antagonist flumazenil. We have also found that the metabotropic ODN receptor is positively coupled to adenylyl cyclase in astrocytes and that the glioprotective action of ODN upon H(2)O(2)-induced astrocyte death is PKA- and MEK-dependent, but PLC/PKC-independent. Downstream of PKA, ODN induced ERK phosphorylation, which in turn activated the expression of the anti-apoptotic gene Bcl-2 and blocked the stimulation by H(2)O(2) of the pro-apoptotic gene Bax. The effect of ODN on the Bax/Bcl-2 balance contributed to abolish the deleterious action of H(2)O(2) on mitochondrial membrane integrity and caspase-3 activation. Finally, the inhibitory effect of ODN on caspase-3 activity was shown to be PKA and MEK-dependent. In conclusion, the present results demonstrate that the potent glioprotective action of ODN against oxidative stress involves the metabotropic ODN receptor coupled to the PKA/ERK-kinase pathway to inhibit caspase-3 activation.     

Two Tunisian patients with Peters plus syndrome harbouring a novel splice site mutation in the B3GALTL gene that modulates the mRNA secondary structure

Peters plus syndrome is an autosomal recessive rare disorder comprising ocular anterior segment dysgenesis, short stature, hand abnormalities, distinctive facial features, and often other major/minor additional defects. Peters plus syndrome is related to mutations in the B3GALTL gene with only seven recently reported mutations, leading to the inactivation of the B1, 3-glucosyltransferase. In this study, we screened the B3GALTL gene in two unrelated patients with typical Peters plus syndrome. A novel homozygous c.597-2A>G mutation was identified in both patients. Bioinformatic analyses showed that this mutation modulates the pre mRNA secondary structure of the gene, and decreases the score value related to the formation of splicing loops. Moreover, the c.597-2A>G mutation is located in a CpG Island of the B3GALTL gene, suggesting a potential epigenetic role of this position including gene's methylation and regulation. These data confirm an important role of the B3GALTL gene test that provides diagnosis confirmation and improves genetic counseling for the families.     

Effects of hexavalent chromium on reproductive functions of male adult rats

Hexavalent chromium is an environmental contaminant which may be associated with reproductive abnormalities in male rats. In the present study, we examined the effect of hexavalent chromium on male reproductive function of rats. Male Wistar rats received a daily intraperitoneal injection of potassium dichromate (1 or 2 mg/kg body weight) for fifteen consecutive days. A decrease in testis weight and an increase in seminal vesicles and prostate weights were demonstrated after chromium treatment. Moreover, a dose-dependent increase in blood and testis chromium levels as well as an increase in FSH and a decrease in LH and testosterone serum levels were detected in treated rats. Histological analysis revealed pronounced morphological alterations with enlarged intracellular spaces, tissue loosening and dramatic loss of gametes in the lumen of the seminiferous tubules of treated rats. In addition, a decreased sperm motility and number of epididymal spermatozoa together with an increased sperm abnormality rate was found in chromium-treated rats in comparison to controls. In rats receiving the higher chromium dose, histological images presented considerably increased areas filled with seminal vesicle and prostate secretions. The mucosal crypts of seminal vesicles and the typical invaginations of prostate were altered. The results suggest that subacute treatment of potassium dichromate promotes reproductive system toxicity and affects testicular function of adult male rats.