Fungicides degradation in an organic biomixture: impact on microbial diversity

Biological systems are being developed all over EU countries to protect water-bodies from pesticide contamination at farm level. A laboratory experiment was carried out to test the efficiency of a mixture of compost and straw in bio-degrading different mixtures of fungicides usually applied in vineyards. At the same time the effects of fungicide applications on microbial community of biomixture were also evaluated. Results showed that the biomixture had a good capability of degrading pesticides. Indeed, at the end of the experiment (112 days), the concentration of most of the pesticides was close to complete degradation. Denaturing gradient gel electrophoresis (DGGE) analysis showed an evident modification of microbial diversity after the addition of fungicides. However, at the end of degradation process, no significant changes in the composition of microbial community were seen. In this specific substrate used in the biomixture, yeast flora and ascomycete filamentous fungi seemed to be involved in the degradation activity.     

Social influences are associated with BMI and weight loss intentions in young adults

Christakis and colleagues have shown that health behaviors cluster in social networks and suggest social norms may account for the clustering. This study examined: (i) whether obesity clusters among young adults and whether social norms do in fact account for the clustering, and (ii) among overweight/obese (OW/OB) young adults, whether number of social contacts trying to lose weight is associated with weight loss intentions and whether social norms for weight loss account for this effect. Normal weight (NW) and OW/OB young adults (N = 288; 66% female; 75% white) completed measures assessing number of OW social contacts and social norms for obesity. OW/OB young adults also indicated number of OW social contacts currently trying to lose weight, social norms for weight loss, and weight loss intentions. Compared to NW, OW/OB young adults were more likely to have OW romantic partners and best friends and had more OW casual friends and family members (Ps < 0.05), but social norms for obesity did not differ between groups, and social norms did not mediate the relationship between OW social contacts and participants' weight status. However, among OW/OB young adults, having more social contacts trying to lose weight was associated with greater intention to lose weight (r = 0.20, P = 0.02) and social norms for weight loss fully mediated this effect (P < 0.01). This study is the first to show that social contacts and normative beliefs influence weight status and intentions for weight control in young adults. Findings underscore the importance of targeting social influence in the treatment and prevention of obesity in this high-risk age group.     

Algebraic and geometric tools in phylogenetics.

In this expository work we describe the main aspects of the so-called Phylogenetic Algebraic Geometry which concerns with the study of algebraic varieties representing statistical models of evolution. In particular, we mainly describe how this field of research can be used to infer phylogenies.     

QSAR study for a novel series of ortho monosubstituted phenoxy analogues of alpha1-adrenoceptor antagonist WB4101

A number of (S)- and (R)-2-[(2-phenoxyethyl)aminomethyl]-1,4-benzodioxanes unsubstituted or ortho monosubstituted at the phenoxy moiety were synthesized and tested in binding assays on the alpha(1a)-AR, alpha(1b)-AR, alpha(1d)-AR and the 5-HT(1A) receptor. The affinity values of the new compounds 1-16 were compared with those of the enantiomers of the 2,6-dimethoxyphenoxy analogue, the well-known alpha(1) antagonist WB4101, finding that the unsubstituted derivative (S)-1 and the o-methyl, the o-t-butyl, the o-fluoro and the o-methoxy derivatives, (S)-2, (S)-4, (S)-8 and (S)-16, respectively, display a significantly specific 5-HT(1A) affinity, very close, with the exception of (S)-4, to the almost nanomolar one of (S)-WB4101. Otherwise, sensible affinity decreases were recorded for the three alpha(1)-AR subtypes. A classical quantitative structure-activity relationship (Hansch) analysis was successfully applied to compounds (S)-1 to (S)-16 and (S)-WB4101 to rationalize such binding data.     

Enhanced susceptibility of staggerer (RORalphasg/sg) mice to lipopolysaccharide-induced lung inflammation

The retinoid-related orphan receptor alpha (RORalpha), a member of the ROR subfamily of nuclear receptors, has been implicated in the control of a number of physiological processes, including the regulation of several immune functions. To study the potential role of RORalpha in the regulation of innate immune responses in vivo, we analyzed the induction of airway inflammation in response to lipopolysaccharide (LPS) challenge in wild-type and staggerer (RORalpha(sg/sg)) mice, a natural mutant strain lacking RORalpha expression. Examination of hematoxylin and eosin-stained lung sections showed that RORalpha(sg/sg) mice displayed a higher degree of LPS-induced inflammation than wild-type mice. Bronchoalveolar lavage (BAL) was performed at 3, 16, and 24 h after LPS exposure to monitor the increase in inflammatory cells and the level of several cytokines/chemokines. The increased susceptibility of RORalpha(sg/sg) mice to LPS-induced airway inflammation correlated with a higher number of total cells and neutrophils in BAL fluids from LPS-treated RORalpha(sg/sg) mice compared with those from LPS-treated wild-type mice. In addition, IL-1beta, IL-6, and macrophage inflammatory protein-2 were appreciably more elevated in BAL fluids from LPS-treated RORalpha(sg/sg) mice compared with those from LPS-treated wild-type mice. The enhanced susceptibility of RORalpha(sg/sg) mice appeared not to be due to a repression of IkappaBalpha expression. Our observations indicate that RORalpha(sg/sg) mice are more susceptible to LPS-induced airway inflammation and are in agreement with the hypothesis that RORalpha functions as a negative regulator of LPS-induced inflammatory responses.     

Circadian rhythms in mouse blood coagulation

The circadian clock, influencing many biological processes, has been demonstrated to modulate levels of specific coagulation factors, but its impact on the coagulation efficiency is unknown. In a mouse model, the authors evaluated the temporal variations in the initial rate of activated factor X (FXa) and thrombin generation. Upon coagulation activation through the FVIIa-TF pathway (extrinsic activation), both parameters showed rhythmic variations with a significant peak at ZT 12, the light-to-dark transition. In mice subjected to a 6-h delayed light-dark cycle, the peak was shifted as expected. These cyclic oscillations were also observed in constant darkness, thus demonstrating, for the first time, the existence of strong circadian rhythms of the initial rate of either FXa or thrombin generation activity levels. These circadian variations overlapped with those that have been recently described in factor VII (FVII) activity. The peak of FXa generation activity was simulated by the addition of purified human FVII, thus indicating that circadian variations in FVII activity are important determinants of the circadian rhythm of the procoagulant cascade efficiency. These findings help to elucidate the complex control on the coagulation process and might contribute in explaining the temporal variations in the frequency of cardiovascular events observed in humans.     

Enhanced biodegradation of transformer oil in soils with cyclodextrin – from the laboratory to the field

The use cyclodextrins for the intensification of bioremediation by improving the mobility and bioavailability of contaminants has recently been studied. In this work, the role of randomly methylated -cyclodextrin in the bioremediation of soils contaminated with transformer oil was studied both in bench scale bioreactors and through field experiments. The aims of this research were to (a) establish the scientific background of a cyclodextrin-based soil bioremediation technology, (b) demonstrate its feasibility and effectiveness in the field, and (c) develop an integrated methodology, consisting of a combination of physical, chemical, biological and ecotoxicological analytical methods, for efficiently monitoring the technology performances. The stepwise increasing scale of the experiments and the application of the integrated analytical methodology supported the development of a scientifically established new technology and the identification of the advantages and the limitations of its application in the field. At each phase of the study, randomly methylated -cyclodextrin was found to significantly enhance the bioremediation and detoxification of the transformer oil-contaminated soils employed by increasing the bioavailability of the pollutants and the activity of indigenous microorganisms.     

Genetic variation and population structure of two species of neo-tropical mud-mussels (Mytella spp)

Mytella guyanensis Lamarck (1819) and Mytella charruana d'Orbigny (1846) are widespread euryhaline bivalves that have become commercially important in Brazil. Despite their importance, however, no genetic information that would be useful to orient governmental policies is available for these species. We analyzed, through allozyme electrophoresis, populations of M. guyanensis and M. charruana along 3,500 km of Brazilian coast. Pairwise comparisons among gene frequencies in M. guyanensis resulted in high levels of pairwise gene identity (I = 0.976 to 0.998). Conversely, significant levels of population structure were found in both M. guyanensis (FST = 0.089) and M. charruana (FST = 0.102). Heterozygosity levels for both species were high (H(e) = 0.090 to 0.134 in M. guyanensis and H(e) = 0.191 to 0.228 in M. charruana). The larger population size of M. charruana could explain, at least partially, the higher levels of genetic variability for this species. These levels of genetic variability yield an effective population size estimate of about 300,000 for M. guyanensis, and 540,000 for M. charruana, based on neutralist expectations. Remarkably, these numbers are much smaller than the estimated actual population sizes. This distortion might be explained by unstable population sizes and it suggests that long-term genetic variability studies are crucial to prevent artifactual viability analysis data for these commercially exploited species.     

Mapping contacts between regulatory domains of skeletal muscle TnC and TnI by analyses of single-chain chimeras

The troponin (Tn) complex is formed by TnC, TnI and TnT and is responsible for the calcium-dependent inhibition of muscle contraction. TnC and TnI interact in an antiparallel fashion in which the N domain of TnC binds in a calcium-dependent manner to the C domain of TnI, releasing the inhibitory effect of the latter on the actomyosin interaction. While the crystal structure of the core cardiac muscle troponin complex has been determined, very little high resolution information is available regarding the skeletal muscle TnI-TnC complex. With the aim of obtaining structural information regarding specific contacts between skeletal muscle TnC and TnI regulatory domains, we have constructed two recombinant chimeric proteins composed of the residues 1-91 of TnC linked to residues 98-182 or 98-147 of TnI. The polypeptides were capable of binding to the thin filament in a calcium-dependent manner and to regulate the ATPase reaction of actomyosin. Small angle X-ray scattering results showed that these chimeras fold into compact structures in which the inhibitory plus the C domain of TnI, with the exception of residues 148-182, were in close contact with the N-terminal domain of TnC. CD and fluorescence analysis were consistent with the view that the last residues of TnI (148-182) are not well folded in the complex. MS analysis of fragments produced by limited trypsinolysis showed that the whole TnC N domain was resistant to proteolysis, both in the presence and in the absence of calcium. On the other hand the TnI inhibitory and C-terminal domains were completely digested by trypsin in the absence of calcium while the addition of calcium results in the protection of only residues 114-137.     

pH dependence of tryptophan synthase catalytic mechanism: I. The first stage, the beta-elimination reaction

The pyridoxal 5'-phosphate-dependent beta-subunit of the tryptophan synthase alpha(2)beta(2) complex catalyzes the condensation of L-serine with indole to form L-tryptophan. The first stage of the reaction is a beta-elimination that involves a very fast interconversion of the internal aldimine in a highly fluorescent L-serine external aldimine that decays, via the alpha-carbon proton removal and beta-hydroxyl group release, to the alpha-aminoacrylate Schiff base. This reaction is influenced by protons, monovalent cations, and alpha-subunit ligands that modulate the distribution between open and closed conformations. In order to identify the ionizable residues that might assist catalysis, we have investigated the pH dependence of the rate of the external aldimine decay by rapid scanning UV-visible absorption and single wavelength fluorescence stopped flow. In the pH range 6-9, the reaction was found to be biphasic with the first phase (rate constants k(1)) accounting for more than 70% of the signal change. In the absence of monovalent cations or in the presence of sodium and potassium ions, the pH dependence of k(1) exhibits a bell shaped profile characterized by a pK(a1) of about 6 and a pK(a2) of about 9, whereas in the presence of cesium ions, the pH dependence exhibits a saturation profile characterized by a single pK(a) of 9. The presence of the allosteric effector indole acetylglycine increases the rate of reaction without altering the pH profile and pK(a) values. By combining structural information for the internal aldimine, the external aldimine, and the alpha-aminoacrylate with kinetic data on the wild type enzyme and beta-active site mutants, we have tentatively assigned pK(a1) to betaAsp-305 and pK(a2) to betaLys-87. The loss of pK(a1) in the presence of cesium ions might be due to a shift to lower values, caused by the selective stabilization of a closed form of the beta-subunit.