Harvest prediction in ‘Algerie’ loquat

Plant phenology is in great measure driven by air temperature. To forecast harvest time for ‘Algerie’ loquat accurately, the growing degree days (GDD) needed from bloom to ripening were determined using data from nine seasons. The methods proposed by Zalom et al. (Zalom FG, Goodell PB, Wilson LT, Barnett WW, Bentley W, Degree-days: the calculation and use of heat units in pest management, leaflet no 21373, Division Agriculture and Natural Resources, University of California 10 pp, 1983) were compared as regards their ability to estimate heat summation based on hourly records. All the methods gave remarkably similar results for our cultivation area, although the double-sine method showed higher performance when temperatures were low. A base temperature of 3°C is proposed for ‘Algerie’ loquat because it provides a coefficient of variation in GDD among seasons of below 5%, and because of its compatibility with loquat growth. Based on these determinations, ‘Algerie’ loquat requires 1,715 GDD from bloom to harvest; under our conditions this heat is accumulated over an average of 159 days. Our procedure permits the ‘Algerie’ harvest date to be estimated with a mean error of 4.4 days (<3% for the bloom-harvest period). GDD summation did not prove superior to the use of the number of calendar days for predicting ‘Algerie’ harvest under non-limiting growing conditions. However, GDD reflects the developmental rate in water-stressed trees better than calendar days. Trees under deficit irrigation during flower development required more time and more heat to ripen their fruits.     

SMAD3 rs17228212 Gene Polymorphism Is Associated with Reduced Risk to Cerebrovascular Accidents and Subclinical Atherosclerosis in Anti-CCP Negative Spanish Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is a complex polygenic inflammatory disease associated with accelerated atherosclerosis and increased risk of cardiovascular (CV) disease. Previous genome-wide association studies have described SMAD3 rs17228212 polymorphism as an important signal associated with CV events. The aim of the present study was to evaluate for the first time the relationship between this gene polymorphism and the susceptibility to CV manifestations and its potential association with the presence of subclinical atherosclerosis assessed by the evaluation of carotid intima-media thickness (cIMT) in patients with RA.

Methods

One thousand eight hundred and ninety-seven patients fulfilling classification criteria for RA were genotyped for SMAD3 rs17228212 gene polymorphism through TaqMan genotyping assay. Also, subclinical atherosclerosis determined by the assessment of cIMT was analyzed in a subgroup of these patients by carotid ultrasonography.

Results

No statistically significant differences were observed when allele frequencies of RA patients with or without CV events were compared. Nevertheless, when RA patients were stratified according to anti-cyclic citrullinated peptide (anti-CCP) status, we found that in RA patients who were negative for anti-CCP antibodies, the presence of C allele of SMAD3 rs17228212 polymorphism conferred a protective effect against the risk of cerebrovascular accident (CVA) after adjustment for demographic and classic CV risk factors (HR [95%CI]=0.36 [0.14–0.94], p=0.038) in a Cox regression model. Additionally, correlation between the presence of C allele of SMAD3 rs17228212 polymorphism and lower values of cIMT was found after adjustment for demographic and classic CV risk factors (p-value=0.0094) in the anti-CCP negative RA patients.

Conclusions

Our results revealed that SMAD3 rs17228212 gene variant is associated with lower risk of CVA and less severe subclinical atherosclerosis in RA patients negative for anti-CCP antibodies. These findings may have importance to establish predictive models of CV disease in RA patients according to anti-CCP status.     

Functional expression of the Erwinia uredovora carotenoid biosynthesis gene crtl in transgenic plants showing an increase of β-carotene biosynthesis activity and resistance to the bleaching herbicide norflurazon

Among the enzymes involved in carotenoid biosynthesis, phytoene desaturase is considered to be a rate-limiting enzyme in this pathway and is also the target of many bleaching herbicides. This enzyme shows diversity concerning its function and amino acid homology among various organisms. The phytoene desaturase gene crtl of Erwinia uredovora was expressed, the 5'-region of which was fused to the sequence for the transit peptide of a pea Rubisco small subunit, in tobacco plants under the control of the CaMV 35S promoter. This chimeric gene product was targeted into chloroplasts and processed in the transgenic plants. The production and processing of the corresponding protein could be demonstrated by Western blotting. Immunogold localization showed that the location of the gene product Crtl was preferentially in the thylakoids. A radioactive labeling study using the leaves demonstrated enhanced activity for the synthesis of β-carotene. In addition, the transgenic tobacco acquired elevated resistance to the bleaching herbicide norflurazon.     

PF 9601N [N-(2-propynyl)-2-(5-benzyloxy-indolyl) methylamine], a new MAO-B inhibitor,attenuates MPTP-induced depletion of striatal dopamine levels in C57/BL6 mice

Monoamine oxidase isoform B (MAO-B) is involved in Parkinson's disease (PD) induced by the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxin (MPTP) in human and non-human-primate. MAO-B inhibitors, such as L-deprenyl have shown to prevent against MPTP-toxicity in different species, and it has been used in Parkinson therapy, however, the fact that it is metabolized to (-)-methamphetamine and (-)-amphetamine highlights the need to find out new MAO-B inhibitors without a structural amphetaminic moiety. In this context we herein report, for the first time, anywhere a novel non-amphetamine-like MAO-B inhibitor, PF 9601N, N-(2-propynyl)-2-(5-benzyloxy-indolyl) methylamine. This attenuates the MPTP-induced striatal dopamine depletion in young-adult and adult-old C57/BL mice, using different schedules of administration, and which behave "ex vivo" as a slightly more potent and selective MAO-B inhibitor than L-deprenyl, assayed for comparative purposes in the same experimental conditions. The MAO-B ID(50) values were calculated from the total MAO-B activity measured against [14C] phenylethylamine (22 microM) as substrate, at each inhibitor concentration. The MAO-B ID(50) values resulted to be 381 and 577 nmol/kg for PF 9601N and L-deprenyl, respectively. The intraperitoneally (i.p.) co-administration to young-adult C57/BL6 mice of MPTP (30 mg/kg), with different concentrations of PF 9601N or L-deprenyl (29.5-0.357 micromol/kg) showed a dose-dependent protective effect against striatal dopamine depletion, measuring the dopamine contents and its metabolites by HPLC. The ED(50) value proved to be 3.07 micromol/kg without any significant differences between either MAO-B inhibitor. Nevertheless, lower doses of PF 9601N (1.5 micromol/kg) were necessary to get almost total protection, without any change in the DOPAC and HVA content, when administered 2 h before MPTP (30 mg/kg), whereas partial protection (45%) against dopamine depletion was observed in the case of L-deprenyl. In both cases, MAO-B inhibition was a necessary condition in order to observe the protective effect. When adult-old (8-10 months) C57/BL6 mice were used, MPTP (25 mg/kg) administration induced 25 days later, an irreversible dopamine depletion. In these conditions, chronic administration with 0.15 micromol/kg of PF 9601N, before the toxin, every 24 h for 10 days, rendered almost total protection of dopamine depletion, whereas L-deprenyl yielded only 50% protection of the dopamine content, assayed in the same conditions. It is worth remarking, that in both cases MAO-B was not affected. From these results, it can be concluded that PF 9601N attenuates MPTP neurotoxicity "in vivo" better than L-deprenyl through different mechanisms, with special relevance to the protective effect, independent of MAO-B inhibition, observed in the irreversibly MPTP-lesioned adult-old mice. Therefore, this novel non-amphetamine MAO-B inhibitor could be potentially effective in PD therapy.     

Influence of maternal stress on uranium-induced developmental toxicity in rats

It has been demonstrated that uranium is an embryo/fetal toxicant when given orally or subcutaneously to pregnant mice. On the other hand, maternal stress has been shown to enhance the developmental toxicity of a number of metals. In this study, maternal toxicity and developmental effects of a concurrent exposure to uranyl acetate dihydrate (UAD) and restraint stress were evaluated in rats. Four groups of pregnant animals were given subcutaneous injections of UAD at 0.415 and 0.830 mg/kg/day on Days 6 to 15 of gestation. Animals in two of these groups were also subjected to restraint for 2 hr/day during the same gestational days. Control groups included restrained and unrestrained pregnant rats not exposed to UAD. Cesarean sections were performed on gestation Day 20, and the fetuses were weighed and examined for malformations and variations. Maternal toxicity and embryotoxicity were noted at 0.830 mg/kg/day of UAD, while fetotoxicity was evidenced at 0.415 and 0.830 mg/kg/day of UAD by significant reductions in fetal body weight and increases in the total number of skeletally affected fetuses. No teratogenic effects were noted in any group. Maternal restraint enhanced uranium-induced embryo/fetal toxicity only at 0.830 mg/kg/day, a dose that was also significantly toxic to the dams. As in previous studies with other metals, maternal stress enhances uranium-induced developmental toxicity at uranium doses that are highly toxic to the dams; however, at doses that are less acutely toxic the role of maternal stress would not be significant.     

Biological and chemical studies on aryl hydrocarbon receptor induction by the p53 inhibitor pifithrin-α and its condensation product pifithrin-β

AimsPifithrin α (PFTα), an inhibitor of the p53 protein, is regarded as a lead compound for cancer and neurodegenerative disease therapy. There is some evidence that this compound activates the aryl hydrocarbon receptor (AhR) in a complete independent way of the p53 inhibition and that it is easily converted to its condensation product pifithrin β (PFTβ). The aim of this study was to explore the ability of PFTα and of PFTβ to induce a variety of AhR mediated processes.Main methodsComputational analysis using quantum chemical calculations and chemical analysis have been used to study the conformation of the compounds as well as the cyclization reaction. The AhR mediated processes of these compounds have been studied in a rainbow trout cell line (RTG-2) and in a rat hepatoma cell line (H4IIE).Key findingsPFTα molecule could not take a planar conformation required for AhR activation whereas PFTβ showed a conformation similar to those of the prototypical AhR ligand β-naphthoflavone. In both cell lines, PFTα and PFTβ provoked different responses related with AhR activation. However, when cyclization of PFTα to PFTβ was hampered by acetylation of the exocyclic nitrogen, all these responses were not observed. These results lead to the conclusion that the activation of the AhR is probably caused by PFTβ instead of PFTα.SignificanceSince PFTα is a promising compound for the development of new pharmaceuticals inhibiting p53, the chemical instability of this compound as well as the capacity of its transformation product should be taken into account.     

Reconstitution and organization of Escherichia coli proto-ring elements (FtsZ and FtsA) inside giant unilamellar vesicles obtained from bacterial inner membranes

We have incorporated, for the first time, FtsZ and FtsA (the soluble proto-ring proteins from Escherichia coli) into bacterial giant unilamellar inner membrane vesicles (GUIMVs). Inside the vesicles, the structural organization and spatial distribution of fluorescently labeled FtsZ and FtsA were determined by confocal microscopy. We found that, in the presence of GDP, FtsZ was homogeneously distributed in the lumen of the vesicle. In the presence of GTP analogs, FtsZ assembled inside the GUIMVs, forming a web of dense spots and fibers. Whereas isolated FtsA was found adsorbed to the inner face of GUIMVs, the addition of FtsZ together with GTP analogs resulted in its dislodgement and its association with the FtsZ fibers in the lumen, suggesting that the FtsA-membrane interaction can be modulated by FtsZ polymers. The use of this novel in vitro system to probe interactions between divisome components will help to determine the biological implications of these findings.     

Testing the suitability of insect orders as indicators for olive farming systems

• 1 A previous study suggested the use of certain insects groups as indicators for detecting organic olive farming in Southern Spain. To validate the use of these groups, insects were collected from olive orchards in Cordoba and Granada, comprising two Andalusian provinces with different surrounding landscapes.
• 2 Canopies were sampled using the branch‐beating technique during pre‐blooming and post‐blooming periods over 3 years in Granada (1999, 2000 and 2003) and 1 year in Cordoba (2003).
• 3 Using a nonparametric linear discriminant analysis method, based on the k‐nearest neighbour algorithm, two discriminant functions were constructed. A first discriminant model took into account interannual variability in Granada Province and the second model focused on environmental heterogeneity between the two provinces. Cross‐validation techniques, such as leave‐one‐out and split‐sample, were applied to the associated discriminant functions for each model to check their performance.
• 4 Even though differences existed with respect to the insect composition of the regions, the second model correctly classified 78.1% of the sampled blocks under the non‐organic and organic farming systems at the same time as taking into account two orders: Coleoptera and Hemiptera [excluding Euphyllura olivina olivina (Psyllidae) and the Heteroptera suborder]. The results suggest that the relative abundance of these groups in the post‐blooming period could constitute a potential bio‐indicator of organic olive farming system.

     

Germination response of Arabian desert species to gibberellic acid and potassium nitrate seed treatment

Abstract

Desert plant species commonly use seed dormancy to prevent germination during unfavorable environmental conditions and thus increase the probability of seedling survival. Seed dormancy presents a challenge for restoration ecology, particularly in desert species for which our knowledge of dormancy regulation is limited. In the present study the effect of gibberellic acid (GA₃) and potassium nitrate (KNO₃) on seed dormancy release was investigated on eight Arabian desert species. Both treatments significantly enhanced the germination of most species tested. GA₃ was more effective than KNO₃ in enhancing germination percentage, reducing mean germination time and synchronizing the germination in most of the studied species. Light requirement during germination was species-specific, but in general the presence of light promoted germination more effectively when combined with KNO₃ and GA₃. The wide variation in dormancy and germination requirements among the tested species is indicative of distinct germination niches, which might assist their co-existence in similar habitat/environmental conditions. Seed pre-treatments that optimize germination in this habitat must therefore be assessed for individual species to improve the outcomes of ecological restoration.     

Skeletons, noise and population growth: the end of an old debate?

Population dynamics models remain largely deterministic, although the presence of random fluctuations in nature is well recognized. This deterministic approach is based on the implicit assumption that systems can be separated into a deterministic part that captures the essential features of the system and a random part that can be neglected. But is it possible, in general, to understand population dynamics without the explicit consideration of random fluctuations? Here, we suggest perhaps not, and argue that the dynamics of many systems are a result of interactions between the deterministic nonlinear skeleton and noise.