The Salt-Stress Response of the Transgenic Plum Line J8-1 and Its Interaction with the Salicylic Acid Biosynthetic Pathway from Mandelonitrile.

Salinity is considered as one of the most important abiotic challenges that affect crop productivity. Plant hormones, including salicylic acid (SA), are key factors in the defence signalling output triggered during plant responses against environmental stresses. We have previously reported in peach a new SA biosynthetic pathway from mandelonitrile (MD), the molecule at the hub of the cyanogenic glucoside turnover in Prunus sp. In this work, we have studied whether this new SA biosynthetic pathway is also present in plum and the possible role this pathway plays in plant plasticity under salinity, focusing on the transgenic plum line J8-1, which displays stress tolerance via an enhanced antioxidant capacity. The SA biosynthesis from MD in non-transgenic and J8-1 micropropagated plum shoots was studied by metabolomics. Then the response of J8-1 to salt stress in presence of MD or Phe (MD precursor) was assayed by measuring: chlorophyll content and fluorescence parameters, stress related hormones, levels of non-enzymatic antioxidants, the expression of two genes coding redox-related proteins, and the content of soluble nutrients. The results from in vitro assays suggest that the SA synthesis from the MD pathway demonstrated in peach is not clearly present in plum, at least under the tested conditions. Nevertheless, in J8-1 NaCl-stressed seedlings, an increase in SA was recorded as a result of the MD treatment, suggesting that MD could be involved in the SA biosynthesis under NaCl stress conditions in plum plants. We have also shown that the plum line J8-1 was tolerant to NaCl under greenhouse conditions, and this response was quite similar in MD-treated plants. Nevertheless, the MD treatment produced an increase in SA, jasmonic acid (JA) and reduced ascorbate (ASC) contents, as well as in the coefficient of non-photochemical quenching (qN) and the gene expression of Non-Expressor of Pathogenesis-Related 1 (NPR1) and thioredoxin H (TrxH) under salinity conditions. This response suggested a crosstalk between different signalling pathways (NPR1/Trx and SA/JA) leading to salinity tolerance in the transgenic plum line J8-1.

Feeding inhibition in Corbicula fluminea (O.F. Muller, 1774) as an effect criterion to pollutant exposure: Perspectives for ecotoxicity screening and refinement of chemical control.

Bivalves are commonly used in biomonitoring programs to track pollutants. Several features, including its filter-feeding abilities, cumulatively argue in favour of the use of the Asian clam (Corbicula fluminea) as a biosentinel and an ecotoxicological model. Filtration in bivalves is very sensitive to external stimuli and its control is dictated by regulation of the opening/closure of the valves, which may be used as an avoidance defence against contaminants. Here, we investigate the filter-feeding behaviour of the Asian clam as an endpoint for assessing exposure to pollutants, driven by two complementary goals: (i) to generate relevant and sensitive toxicological information based on the ability of C. fluminea to clear an algal suspension, using the invasive species as a surrogate for native bivalves; (ii) to gain insight on the potential of exploring this integrative response in the refinement of chemical control methods for this pest. Clearance rates and proportion of algae removed were measured using a simple and reproducible protocol. Despite some variation across individuals and size classes, 50-90% of food particles were generally removed within 60-120 min by clams larger than 20 mm. Removal of algae was sensitive to an array of model contaminants with biocide potential, including fertilizers, pesticides, metals and salts: eight out of nine tested substances were detected at the µg l-1 or mg l-1 range and triggered valve closure, decreasing filter-feeding in a concentration-dependent manner. For most toxicants, a good agreement between mortality (96 h - LC50 within the range 0.4-5500 mg l-1) and feeding (2 h - IC50 within the range 0.005-2317 mg l-1) was observed, demonstrating that a 120-min assay can be used as a protective surrogate of acute toxicity. However, copper sulphate was very strongly avoided by the clams (IC50 = 5.3 µg l-1); on the contrary, dichlorvos (an organophosphate insecticide) did not cause feeding depression, either by being undetected by the clams' chemosensors and/or by interfering with the valve closure mechanism. Such an assay has a large potential as a simple screening tool for industry, environmental agencies and managers. The ability of dichlorvos to bypass the Asian clam's avoidance strategy puts it in the spotlight as a potential agent to be used alone or combined with others in eradication programs of this biofouler in closed or semi-closed industrial settings.

Phosphate dissolving fungi: Mechanism and application in alleviation of salt stress in wheat.

The present investigation reveals the solubilization efficiency of tri-calcium phosphate (TCP), Udaipur rock phosphate (URP), aluminium phosphate (AP) and ferric phosphate (FP) by Aspergillus niger (ITCC 6719) and Trichoderma harzianum (ITCC 6721) as function of carbon concentrations. Increasing glucose concentration from 1 to 7% in the growth medium, though improved the phosphorus (P) solubilization significantly but each fungal strain preferred different optimum carbon concentrations for mediating solubilization of different P sources. The two fungi employed different mechanisms to reduce medium pH for release of P from TCP, AP and FP. However, URP was solubilized solely through fungal production of citric, succinic, propionic, malic and acetic acid. A linear increase in citric acid production with increasing carbon concentration was recorded during FP solubilization by T. harzianum. The cell free culture filtrate of A. niger detected high phytase and low acid phosphatase activity titre whereas results were vice versa for T. harzianum. Both the fungal strains possessed plant growth promoting attributes such as auxin and sidreophore production and could solubilize Zn. In hydroponic system (with 60mM of sodium chloride concentration), supplementation with culture filtrate from each fungal strain increased the shoot growth of wheat seedlings significantly compared to non culture filtrate control. Use of A.niger as bio-inoculant could be a sustainable approach to improve soil P availability, promote plant growth and alleviate adverse effect of salt stress.

Oral CoQ10 attenuates high salt-induced hypertension by restoring neurotransmitters and cytokines in the hypothalamic paraventricular nucleus.

High salt intake leads to an increase in some proinflammatory cytokines and neurotransmitters involved in the pathogenesis of hypertension. The purpose of this work was to know if oral administration of anti-oxidant and free-radical scavenger CoQ10 may attenuate high salt-induced hypertension via regulating neurotransmitters and cytokines in the hypothalamic paraventricular nucleus (PVN). Adult male Sprague-Dawley (SD) rats were fed with a normal salt diet (NS, 0.3% NaCl) or a high salt diet (HS, 8% NaCl) for 15 weeks to induce hypertension. These rats received CoQ10 (10 mg/kg/day) dissolved in olive oil was given by gavage (10 mg/kg/day) for 15 weeks. HS resulted in higher mean arterial pressure (MAP) and the sympathetic nerve activity (RSNA). These HS rats had higher PVN levels of norepinephrine (NE), tyrosine hydroxylase (TH), interleukin (IL)-1ß, NOX2 and NOX4, lower PVN levels of gamma-aminobutyric acid (GABA), IL-10, copper/zinc superoxide dismutase (Cu/Zn-SOD) and the 67-kDa isoform of glutamate decarboxylase (GAD67), as compared with NS group. CoQ10 supplementation reduced NE, TH, IL-1ß, NOX2 and NOX4 in the PVN, and induced IL-10, Cu/Zn-SOD and GAD67 in the PVN. These findings suggest that CoQ10 supplementation restores neurotransmitters and cytokines in the PVN, thereby attenuating high salt-induced hypertension.

Evaluation of a new battery of toxicity tests for boreal forest soils: assessment of the impact of hydrocarbons and salts.

The ability to assess the toxic potential of soil contamination within boreal regions is currently limited to test species representative of arable lands. This study evaluated the use of six boreal plant species (Pinus banksiana, Picea glauca, Picea mariana, Populus tremuloides, Calamagrostis Canadensis, and Solidago canadensis) and four invertebrate species (Dendrodrilus rubidus, Folsomia nivalis, Proisotoma minuta, and Oppia nitens) and compared their performance to a suite of standard agronomic soil test species using site soils impacted by petroleum hydrocarbon (PHC) and salt contamination. To maintain horizon-specific differences, individual soil horizons were collected from impacted sites and relayered within the test vessels. Use of the boreal species was directly applicable to the assessment of the contaminated forest soils and, in the case of the hydrocarbon-impacted soil, demonstrated greater overall sensitivity (25th percentile of estimated species sensitivity distribution [ESSD25] = 5.6% contamination: 10,600 mg/kg fraction 3 [F3; equivalent hydrocarbon range of >C16 to C34] Of/Oh horizon, and 270 mg/kg F3 Ahg horizon) relative to the standard test species (ESSD25 = 23% contamination: 44,000 mg/kg F3 Of/Oh horizon, and 1,100 mg/kg F3 Ahg horizon). For salinity, there was no difference between boreal and standard species with a combined ESSD25 = 2.3%, equating to 0.24 and 0.25 dS/m for the Ah and Ck horizons. The unequal distribution of soil invertebrates within the layered test vessels can confound test results and the interpretation of the toxic potential of a site. The use of test species relevant to boreal eco-zones strengthens the applicability of the data in support of realistic ecological risk assessments applicable to the boreal regions.

Characterization of strains unlike Mesorhizobium loti that nodulate lotus spp. in saline soils of Granada, Spain.

Lotus species are forage legumes with potential as pastures in low-fertility and environmentally constrained soils, owing to their high persistence and yield under those conditions. The aim of this work was the characterization of phenetic and genetic diversity of salt-tolerant bacteria able to establish efficient symbiosis with Lotus spp. A total of 180 isolates able to nodulate Lotus corniculatus and Lotus tenuis from two locations in Granada, Spain, were characterized. Molecular identification of the isolates was performed by repetitive extragenic palindromic PCR (REP-PCR) and 16S rRNA, atpD, and recA gene sequence analyses, showing the presence of bacteria related to different species of the genus Mesorhizobium: Mesorhizobium tarimense/Mesorhizobium tianshanense, Mesorhizobium chacoense/Mesorhizobium albiziae, and the recently described species, Mesorhizobium alhagi. No Mesorhizobium loti-like bacteria were found, although most isolates carried nodC and nifH symbiotic genes closely related to those of M. loti, considered the type species of bacteria nodulating Lotus, and other Lotus rhizobia. A significant portion of the isolates showed both high salt tolerance and good symbiotic performance with L. corniculatus, and many behaved like salt-dependent bacteria, showing faster growth and better symbiotic performance when media were supplemented with Na or Ca salts.

Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater.

Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10 degrees C for up to 5 weeks. Cumulative production of (14)CO(2) was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl >or=1% (w/v) delayed the onset of mineralization of both (14)C-hexadecane and (14)C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0-5% NaCl). For Site B, increasing concentrations of NaCl >or=1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (

Effects of a mixture of vegetable and essential oils and fatty acid potassium salts on Tetranychus urticae and Phytoseiulus persimilis.

Laboratory trials were carried out to evaluate the toxicity and the influence of a commercial mixture of vegetal, essential oils, and potassium salts of fatty acids (Acaridoil 13SL) on the population growth rate (r(i)--instantaneous rate of increase) of two mite species, the phytophagous Tetranychus urticae Koch and the predator Phytoseiulus persimilis Athias-Henriot. A residue of 1.3 mg/cm(2) of pesticide solution was harmless for Ph. persimilis eggs, while a moderate mortality of eggs and of larvae from treated eggs of T. urticae, was observed (53.8%). The pesticide also caused a delay in the postembryonic development of the tetranychid. Moreover, 83.4% mortality was reported for treated females tetranychids and only 24.0% for Ph. persimilis females. The pesticide influenced negatively the population growth of T. urticae which showed a very low rate of increase (r(i)=0.07), compared to that obtained in the control (r(i)=0.68). The pesticide did not affect negatively the reproductive potential of Ph. persimilis (r(i)=0.54 and r(i)=0.57 for test and control, respectively). These results suggest a considerable acaricidal activity of potassium salts of fatty acids and caraway oil on T. urticae and a good selectivity on Ph. persimilis.

Lymphocytic inflammation produced by intracerebral implantation of zinc and other metals.

Sxteen pure metals were implanted as pellets of powder or as wires into the brains of rats. Al, Be, Cr, Fe, Pb, Sn, and W were relatively innocuous. Mg and Mn produced local necrosis. Bi, Cd, Co, Cu and Ni produced more severe local necrosis. Viable tissue adjacent to Co and Ni necrotic lesions had some perivascular lymphocytic infiltrates. Zn implants caused very little necrosis but adjacent areas had prominent perivascular lymphocytic cuffs. The infiltrates persisted for at least 4 weeks but disappeared as soon as the zinc was removed. Some compounds of zinc were also capable of inducing infiltrates. The perivascular infiltrates resembled the lesions of allergic encephalomyelitis, but there was no correlation between the ability of metal powders to induce lymphocytic infiltrates after intracerebral implantation and their adjuvancy after intraperitoneal injection with neural antigen.