Advantages of using microbial technology over traditional chemical technology in removal of black crusts from stone surfaces of historical monuments

This study compares two cleaning methods, one involving an ammonium carbonate-EDTA mixture and the other involving the sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, for the removal of black crust (containing gypsum) on marble of the Milan Cathedral (Italy). In contrast to the chemical cleaning method, the biological procedure resulted in more homogeneous removal of the surface deposits and preserved the patina noble under the black crust. Whereas both of the treatments converted gypsum to calcite, allowing consolidation, the chemical treatment also formed undesirable sodium sulfate.     

<Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> AtGpp1 and AtGpp2: two novel low molecular weight phosphatases involved in plant glycerol metabolism

We have isolated two Arabidopsis thaliana genes, AtGpp1 and AtGpp2, showing homology with the yeast low molecular weight phosphatases GPP1 and GPP2, which have a high specificity for dl-glycerol-3-phosphate, and moreover homology with DOG1 and DOG2 that dephosphorylate 2-deoxyglucose-6-phosphate. Using a comparative genomic approach, the corresponding genes were identified as conceptual translated haloacid dehalogenase-like hydrolase proteins. AtGpp1 (gi 18416631) and AtGpp2 (gi 18423981), encode proteins that share 95% identity, with a predicted Mw of 33 and 27 kDa and a pI of 7.8 and 5.6, respectively. Both isoforms have a high specificity for dl-glycerol-3-phosphate, pH optima at 7.0, and K _m in the range of 3.5–5.2 mM. AtGpp1 and AtGpp2 are expressed throughout development in all plant organs, most strongly in siliqua, and expression is not affected by osmotic, ionic or oxidative stress. A putative chloroplast transit peptide cTP-containing sequence is appended to the AtGpp1 N-terminus while AtGpp2, devoid of this tail, is predicted to be in the extraplastidial cytosol; this compartmenting was further confirmed by subcellular fractionation. An immunohystochemical localization study, using anti-AtGpp2 antibodies, indicates that the AtGpp proteins are mainly restricted to the meristem of immature flower and vascular elements of the root, shoot, leave, siliqua and developing embryo. Considerable immunoreaction was observed in the cytoplasm as well as in plastid compartments of distinct cells types from different heterotrophic Arabidopsis tissues, and particularly localised within phloem companion cells. Transgenic Arabidopsis plants, with gain of AtGpp2 function, show altered phosphatase activity rates and improved tolerance to salt, osmotic and oxidative stress.     

Determination of the optimal therapeutic protocols in cancer immunotherapy

Cancer immunotherapy aims at eliciting an immune system response against the tumor. However, it is often characterized by toxic side-effects. Limiting the tumor growth and, concurrently, avoiding the toxicity of a drug, is the problem of protocol design. We formulate this question as an optimization problem and derive an algorithm for its solution. Unlike the standard optimal control approach, the algorithm simulates impulse-like drug administrations. It relies on an exact computation of the gradient of the cost function with respect to any protocol by means of the variational equations, that can be solved in parallel with the system. In comparison with previous versions of this method [F. Castiglione, B. Piccoli, Optimal control in a model of dendritic cell transfection cancer immunotherapy, Bull. Math. Biol. 68 (2006) 255-274; B. Piccoli, F. Castiglione, Optimal vaccine scheduling in cancer immunotherapy, Physica A. 370 (2) (2007) 672-680], we optimize both the timing and the dosage of each administration and introduce a penalty term to avoid clustering of subsequent injections, a requirement consistent with the clinical practice. In addition, we implement the optimization scheme to simulate the case of multi-therapies. The procedure works for any ODE system describing the pharmacokinetics and pharmacodynamics of an arbitrary number of therapeutic agents. In this work, it was tested for a well known model of the tumor-immune system interaction [D. Kirschner, J.C. Panetta, Modeling immunotherapy of tumor-immune interaction, J. Math. Biol. 37 (1998) 235-252]. Exploring three immunotherapeutic scenarios (CTL therapy, IL-2 therapy and combined therapy), we display the stability and efficacy of the optimization method, obtaining protocols that are successful compromises between various clinical requirements.     

Assessment of environmental stress by the micronucleus and comet assays on Limnoperna fortunei exposed to Guaíba hydrographic region samples (Brazil) under laboratory conditions

The Guaíba Basin is a source of drinking water for Porto Alegre (RS, Brazil). The water from this basin receives industrial, urban, and rural waste from many sources. The mussel species Limnoperna fortunei was chosen based on population data, distribution, and sensitivity. Previous tests with comet assay and micronuclei frequency in this freshwater mussel have shown to be successful in biomonitoring studies. The aim of this study was to evaluate the genotoxic contamination of the Guaíba Lake Hydrographic Region, through the determination of damage by the micronuclei and comet assays in L. fortunei (golden mussel). Nine sampling sites were evaluated in three different seasons: five sites in the mouths of the main rivers that flow into Guaíba lake; one site at the mouth of a stream; one major site of sewage discharge; two sites at Guaíba lake, near a sewage discharge; and the control site in a preservation area. DNA damage was detected by the single cell gel assay, as well as the frequency of micronuclei in hemocytes of mussels exposed under laboratory conditions for 7 days to water and sediment samples. Significant results were found in different seasons in almost all sampling sites (P<0.05, ANOVA Dunnet's test). Most of the positive results were found in samples affected mainly by urban effluents. It was possible to observe that there was a weak relation between mutagenic and genotoxic responses and mussels inorganic elements contents. Seasonal variation was observed at different sampling sites, but always indicating a huge contamination near urban sewage discharge. These results are consistent with previous studies, allowing us to infer that urban contamination is the biggest problem in this region. It is also possible to infer that L. fortunei is a good sentinel organism for the Guaíba Basin.     

Age and nutrient limitation enhance polyunsaturated aldehyde production in marine diatoms

Skeletonema marinoi produces 2,4-heptadienal, 2,4-octadienal, and 2,4,7-octatrienal, the latter only in traces. In nutrient-replete cultures, the production of potentially defensive polyunsaturated aldehydes (PUA) increases from the exponential to the stationary phase of growth from 1.2 fmol cell(-1) (+/-0.4 fmol cell(-1) SD) to 4.2 fmol cell(-1) (+/-1.0 fmol cell(-1) SD), with 2,4-heptadienal as the dominant aldehyde. The plasticity of PUA production with age of the culture supports the hypothesis of a direct link between toxin production and cell physiological state. N- and P-limited cells in stationary phase produced 1.4 and 1.8 fold higher amounts of PUA than control cultures and 10.7 and 4.6 times higher PUAs when compared to their own exponential growth phase, respectively. The increase in PUA production in the nutrient-limited cultures was not paralleled by an increase in the total amount of precursor fatty acids indicating that physiological stress might trigger an enhanced expression or activity of the enzymes responsible for PUA production, i.e. chemical defense increase in aged and nutrient-stressed diatoms. If this holds true during blooms, grazers feeding at the end of a bloom would be more affected than early-bloom grazers.     

Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria

The isocoumarins (1-50 microM) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin isolated from Paepalanthus bromelioides, were assessed for antioxidant activity using isolated rat liver mitochondria and non-mitochondrial systems, and compared with the flavonoid quercetin. The paepalantine and paepalantine dimers, but not vioxanthin, were effective at scavenging both 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) and superoxide (O(2)(-)) radicals in non-mitochondrial systems, and protected mitochondria from tert-butylhydroperoxide-induced H(2)O(2) accumulation and Fe(2+)-citrate-mediated mitochondrial membrane lipid peroxidation, with almost the same potency as quercetin. These results point towards paepalantine, followed by paepalantine dimer, as being a powerful agent affording protection, apparently via O(2)(-) scavenging, from oxidative stress conditions imposed on mitochondria, the main intracellular source and target of those reactive oxygen species. This strong antioxidant action of paepalantine was reproduced in HepG2 cells exposed to oxidative stress condition induced by H(2)O(2).     

EGCG, a green tea polyphenol, improves endothelial function and insulin sensitivity, reduces blood pressure, and protects against myocardial I/R injury in SHR

Epigallocatechin gallate (EGCG), a bioactive polyphenol in green tea, may augment metabolic and vascular actions of insulin. Therefore, we investigated effects of EGCG treatment to simultaneously improve cardiovascular and metabolic function in spontaneously hypertensive rats (SHR; model of metabolic syndrome with hypertension, insulin resistance, and overweight). In acute studies, EGCG (1-100 microM) elicited dose-dependent vasodilation in mesenteric vascular beds (MVB) isolated from SHR ex vivo that was inhibitable by N(omega)-nitro-L-arginine methyl ester (L-NAME; nitric oxide synthase antagonist) or wortmannin [phosphatidylinositol (PI) 3-kinase inhibitor]. In chronic studies, 9-wk-old SHR were treated by gavage for 3 wk with EGCG (200 mg.kg(-1).day(-1)), enalapril (30 mg.kg(-1).day(-1)), or vehicle. A separate group of SHR receiving L-NAME (80 mg/l in drinking water) was treated for 3 wk with either EGCG or vehicle. Vasodilator actions of insulin were significantly improved in MVB from EGCG- or enalapril-treated SHR (when compared with vehicle-treated SHR). Both EGCG and enalapril therapy significantly lowered systolic blood pressure (SBP) in SHR. EGCG therapy of SHR significantly reduced infarct size and improved cardiac function in Langendorff-perfused hearts exposed to ischemia-reperfusion (I/R) injury. In SHR given L-NAME, beneficial effects of EGCG on SBP and I/R were not observed. Both enalapril and EGCG treatment of SHR improved insulin sensitivity and raised plasma adiponectin levels. We conclude that acute actions of EGCG to stimulate production of nitric oxide from endothelium using PI 3-kinase-dependent pathways may explain, in part, beneficial effects of EGCG therapy to simultaneously improve metabolic and cardiovascular pathophysiology in SHR. These findings may be relevant to understanding potential benefits of green tea consumption in patients with the metabolic syndrome.     

Outdoor cultivation of lutein-rich cells of <Emphasis Type="Italic">Muriellopsis</Emphasis> sp. in open ponds

The growth performance of the chlorophycean microalga Muriellopsis sp. outdoors in open tanks agitated with a paddlewheel and its ability to accumulate carotenoids have been evaluated throughout the year. The cells grown in the open system had free lutein as the main carotenoid, with violaxanthin, β-carotene, and neoxanthin also present. Lutein content of the dry biomass ranged from 0.4 to 0.6%, depending on the growth and environmental conditions. In addition, the biomass of Muriellopsis sp. had a high content in both protein and lipids with about half of the fatty acids being of the polyunsaturated type, with α-linolenic acid accounting for almost 30% of the total fatty acids. The effect of determinant parameters on the performance of the cultures in open tanks was evaluated. Operating conditions that allow the maintenance of productive cultures were established under semicontinuous regime for 9 months throughout the year. Biomass and lutein yields in the open system were not far from those in closed tubular photobioreactors, and reached productivity values of 20 g dry biomass, containing around 100 mg lutein m⁻² day⁻¹ in summer. The outdoor culture of Muriellopsis sp. in open ponds thus represents a real alternative to established systems for the production of lutein.