Biopesticide effect of green compost against fusarium wilt on melon plants

AIMS: The biopesticide effect of four green composts against fusarium wilt in melon plants and the effect of soil quality in soils amended with composts were assayed. METHODS AND RESULTS: The composts consisted of pruning wastes, with or without addition of coffee wastes (3/1 and 4/1, dry wt/dry wt) or urea (1000/1, dry wt/dry wt). In vitro experiments suggested the biopesticide effect of the composts against Fusarium oxysporum, while only the compost of pine bark and urea (1000/1dry wt/dry wt) had an abiotic effect. Melon plant growth with composts and F. oxysporum was one to four times greater than in the non-amended soil, although there was no significant decrease in the level of the F. oxysporum in the soil. The addition of composts to the soil also improved its biological quality, as assessed by microbiological and biochemical parameters: ATP and hydrolases involved in the P (phosphatase), C (beta-glucosidase) and N (urease) cycles. CONCLUSIONS: Green composts had greater beneficial characteristics, improved plant growth and controlled fusarium wilt in melon plants. These composts improve the soil quality of semi-arid agricultural soils. SIGNIFICANCE AND IMPACT OF THE STUDY: Biotic and abiotic factors from composts have been tested as responsible of their biopesticide activity against fusarium wilt.     

High density of long dinucleotide microsatellites in Drosophila subobscura

We isolated 96 dinucleotide repeats with five or more tandemly repeated units from a subgenomic Drosophila subobscura library. The mean repeat unit length of microsatellite clones in D. subobscura is 15, higher than that observed in other Drosophila species. Population variation was assayed in 32-40 chromosomes from Barcelona, Spain, using 18 randomly chosen microsatellite loci. Positive correlation between measures of variation and perfect repeat length measures (mean size, most common, and longest allele) is consistent with a higher mutation rate in loci with longer repeat units. Levels of microsatellite variation measured as variance in repeat number and heterozygosity in D. subobscura were similar to those of Drosophila pseudoobscura and higher than those of Drosophila melanogaster and Drosophila simulans. Our data suggest that higher levels of microsatellite variation, and possibly density, in D. subobscura compared with D. melanogaster are due to both a higher average effective population and a higher intrinsic slippage rate in the former species.     

Low-dose tolerance is mediated by the microfold cell ligand, reovirus protein sigma1

Mucosal tolerance induction generally requires multiple or large Ag doses. Because microfold (M) cells have been implicated as being important for mucosal tolerance induction and because reovirus attachment protein sigma1 (psigma1) is capable of binding M cells, we postulated that targeting a model Ag to M cells via psigma1 could induce a state of unresponsiveness. Accordingly, a genetic fusion between OVA and the M cell ligand, reovirus psigma1, termed OVA-psigma1, was developed to enhance tolerogen uptake. When applied nasally, not parenterally, as little as a single dose of OVA-psigma1 failed to induce OVA-specific Abs even in the presence of adjuvant. Moreover, the mice remained unresponsive to peripheral OVA challenge, unlike mice given multiple nasal OVA doses that rendered them responsive to OVA. The observed unresponsiveness to OVA-psigma1 could be adoptively transferred using cervical lymph node CD4(+) T cells, which failed to undergo proliferative or delayed-type hypersensitivity responses in recipients. To discern the cytokines responsible as a mechanism for this unresponsiveness, restimulation assays revealed increased production of regulatory cytokines, IL-4, IL-10, and TGF-beta1, with greatly reduced IL-17 and IFN-gamma. The induced IL-10 was derived predominantly from FoxP3(+)CD25(+)CD4(+) T cells. No FoxP3(+)CD25(+)CD4(+) T cells were induced in OVA-psigma1-dosed IL-10-deficient (IL-10(-/-)) mice, and despite showing increased TGF-beta1 synthesis, these mice were responsive to OVA. These data demonstrate the feasibility of using psigma1 as a mucosal delivery platform specifically for low-dose tolerance induction.     

On the use of the quenching of luminol luminescence to evaluate sod activity

Addition of horseradish peroxidase to a luminol solution (pH = 9.4) produces a burst of light followed by a steady luminescence that lasts for several minutes. This steady-state luminescence is readily quenched by SOD, with a concentration (the additive concentration needed to decrease by one-half the emitted luminescence intensity) of c.a. 4 ng/ml (14 mU/ml). The luminescence intensity decrease can then be employed to evaluate SOD activity in SOD-containing samples. However, the light intensity can also be quenched by additives, such as Trolox, that are able to trap luminol-derived intermediates. It is proposed that double quenching experiments must be performed in order to be able to relate the observed effect of an additive to its SOD-like activity.     

Determination of lamotrigine in human serum by liquid chromatography

A rapid high-performance liquid chromatographic method was developed using a short silica column (30 mm×4.6 mm) with an aqueous methanol mobile phase consisting of methanol–water–NH₄H₂PO₄ (94:5.96:0.04) adjusted to a final apparent pH of 5.0 and pumped at a flow-rate of 1 ml/min. Ultraviolet detection was carried out at a wavelength of 280 nm, and serum samples were prepared for HPLC analysis by extraction into dichloromethane after basification. Lamotrigine was eluted at 0.96 min. Within-day variation of the method was 4.46% at 0.75 μg/ml and 2.37% at 6.0 μg/ml, and day-to-day variation was 9.10% at 0.75 μg/ml and 7.28% at 6.0 μg/ml.     

Contribution of the NH2 terminus of Kv2.1 to channel activation

Opening and closing of voltage-operated channels requires theinteraction of diverse structural elements. One approach to theidentification of channel domains that participate in gating is tolocate the sites of action of modifiers. Covalent reaction of Kv2.1channels with the neutral, sulfhydryl-specificmethylmethanethiosulfonate (MMTS) caused a slowing of channel gatingwith a predominant effect on the kinetics of activation. These effectswere also obtained after intracellular, but not extracellular,application of a charged MMTS analog. Single channel analysis revealedthat MMTS acted primarily by prolonging the latency to first openingwithout substantially affecting gating transitions after the channelfirst opens and until it inactivates. To localize the channelcysteine(s) with which MMTS reacts, we generatedNH₂- and COOH-terminal deletion mutants and a construct in which all three cysteines in transmembrane regions were substituted. Only theNH₂-terminal deletion construct gave rise to currents that activated slowly and displayedMMTS-insensitive kinetics. These results show that theNH₂-terminal tail of Kv2.1 participates in transitions leading to activation through interactions involving reduced cysteine(s) that can be modulated from thecytoplasmic phase.

     

Effect of sanitized and non-sanitized sewage sludge on soil microbial community and the physiology of pepper plants

A greenhouse experiment was conducted to investigate the impact of sanitized (Autothermal Thermophilic Aerobic Digested, ATAD) and non-sanitized (Anaerobic Mesophile Digested) sewage sludge on the activity and functional diversity of soil microbial community and the physiology of pepper plants (Capsicum annuum L. cv. Piquillo). ATAD and anaerobic mesophile sludges were applied to soils at three rates (3, 6 and 12 g (dry matter) per pot) and unamended soil was included as a control. Results showed that ATAD and mesophile sludge application increased the growth and yield of plants, and accelerated their phenological development as the sludge rate increased. The increased growth was a result of the enhanced capacity of plants to produce more leaves and the greater photosynthetic activity per unit leaf area. Besides nutrient supply, the increased soil microbial activity and biomass in amended soils might have indirectly contributed to the enhanced growth and yield of plants. Sludge application decreased soil functional diversity and caused a shift in the community-level physiological profile. Although ATAD and anaerobic mesophile sludges exerted similar effects on plant development, the type of sludge influenced the activity and functional diversity of soil microbial community. Results are discussed in relation to the environmental benefits associated with the ATAD process for sludge treatment.     

DREAM-Dependent Activation of Astrocytes in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of unknown origin and characterized by a relentless loss of motor neurons that causes a progressive muscle weakness until death. Among the several pathogenic mechanisms that have been related to ALS, a dysregulation of calcium-buffering proteins in motor neurons of the brain and spinal cord can make these neurons more vulnerable to disease progression. Downstream regulatory element antagonist modulator (DREAM) is a neuronal calcium-binding protein that plays multiple roles in the nucleus and cytosol. The main aim of this study was focused on the characterization of DREAM and glial fibrillary acid protein (GFAP) in the brain and spinal cord tissues from transgenic SOD1^G93A mice and ALS patients to unravel its potential role under neurodegenerative conditions. The DREAM and GFAP levels in the spinal cord and different brain areas from transgenic SOD1^G93A mice and ALS patients were analyzed by Western blot and immunohistochemistry. Our findings suggest that the calcium-dependent excitotoxicity progressively enhanced in the CNS in ALS could modulate the multifunctional nature of DREAM, strengthening its apoptotic way of action in both motor neurons and astrocytes, which could act as an additional factor to increase neuronal damage. The direct crosstalk between astrocytes and motor neurons can become vulnerable under neurodegenerative conditions, and DREAM could act as an additional switch to enhance motor neuron loss. Together, these findings could pave the way to further study the molecular targets of DREAM to find novel therapeutic strategies to fight ALS.