Copper removal by algae Gelidium, agar extraction algal waste and granulated algal waste: kinetics and equilibrium

Biosorption of copper ions by an industrial algal waste, from agar extraction industry has been studied in a batch system. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction, and the industrial waste immobilized with polyacrylonitrile (composite material). The effects of contact time, pH, ionic strength (IS) and temperature on the biosorption process have been studied. Equilibrium data follow both Langmuir and Langmuir-Freundlich models. The parameters of Langmuir equilibrium model were: q(max)=33.0mgg(-1), K(L)=0.015mgl(-1); q(max)=16.7mgg(-1), K(L)=0.028mgl(-1) and q(max)=10.3mgg(-1), K(L)=0.160mgl(-1) respectively for Gelidium, algal waste and composite material at pH=5.3, T=20 degrees C and IS=0.001M. Increasing the pH, the number of deprotonated active sites increases and so the uptake capacity of copper ions. In the case of high ionic strengths, the contribution of the electrostatic component to the overall binding decreases, and so the uptake capacity. The temperature has little influence on the uptake capacity principally for low equilibrium copper concentrations. Changes in standard enthalpy, Gibbs energy and entropy during biosorption were determined. Kinetic data at different solution pH (3, 4 and 5.3) were fitted to pseudo-first-order and pseudo-second-order models. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model, which successfully predicts Cu(II) concentration profiles.     

Identification of a Potential Lead Structure for Designing New Antimicrobials to Treat Infections Caused by Staphylococcus epidermidis-Resistant Strains

Bacterial infections are a significant cause of morbidity and mortality among critically ill patients. The increase of antibiotic resistance in bacteria from human microbiota—such as Staphylococcus epidermidis, an important nosocomial pathogen that affects immunocompromised patients or those with indwelling devices—increased the desire for new antibiotics. In this study we designed, synthesized, and determined the antimicrobial activity of 27 thieno[2,3-b]pyridines (1, 2, 2a–2m, 3, 3a–3m) derivatives against a drug-resistant clinical S. epidermidis strain. In addition, we performed a structure-activity relationship analysis using a molecular modeling approach, and discuss the drug absorption, distribution, metabolism, excretion, and toxicity profile and Lipinski’s “rule of five,” which are tools to assess the relationship between structures and drug-like properties of active compounds. Our results showed that compound 3b (5-(1H-tetrazol-5-yl)-4-(3`-methylphenylamino)thieno[2,3-b]pyridine) was as active as oxacillin and chloramphenicol but with lower theoretical toxicity risks and a better drug likeness and drug score potential than chloramphenicol. All molecular modeling and biological results reinforced the promising profile of 3b for further experimental investigation and development of new antibacterial drugs. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic susceptibility to obsessive-compulsive hoarding: the contribution of neurotrophic tyrosine kinase receptor type 3 gene

Recent work suggests that neurotrophic factors may contribute to the genetic susceptibility to obsessive-compulsive disorder (OCD). Among other clinical dimensions, the presence of hoarding obsessions and compulsions has been shown to be correlated with a number of clinical and neuroimaging findings, as well as with a different pattern of genetic inheritance. We used a linkage disequilibrium (LD)-mapping approach to investigate whether neurotrophic tyrosine kinase receptor type 3 (NTRK3), the high-affinity receptor of neurotrophin 3 (NT-3), plays a role in increasing susceptibility to hoarding in OCD. We performed an association study of 52 tag single nucleotide polymorphisms (tagSNPs) covering the whole NTRK3 gene in a sample comprising 120 OCD patients and 342 controls. Single nucleotide polymorphism association and haplotype analysis were performed. Thirty-six of our patients (30%) exhibited significant hoarding obsessions and compulsions. A significant association of two SNPs in the 3' downstream region of NTRK3 gene and obsessive-compulsive hoarding was identified: rs1017412 [odds ratio (OR) = 2.16; P = 0.001] and rs7176429 (OR = 2.78; P = 0.0001), although only the latter remained significant after Bonferroni correction. Although the haplotype analysis did not show significant results, a more extended block of LD in the OCD hoarders with respect to the control group was observed, suggesting a lower haplotype diversity in these individuals. Our findings suggest that NTRK3 may contribute to the genetic susceptibility to hoarding in OCD and may constitute an interesting gene to focus on in studies of the genetic basis of obsessive-compulsive hoarding.     

SNP analysis to results (SNPator): a web-based environment oriented to statistical genomics analyses upon SNP data

Single nucleotide polymorphisms (SNPs) are the most widely used marker in studies to assess associations between genetic variants and complex traits or diseases. They are also becoming increasingly important in the study of the evolution and history of humans and other species. The analysis and processing of SNPs obtained thanks to high-throughput technologies imply the time consuming and costly use of different, complex and usually format-incompatible software. SNPator is a user-friendly web-based SNP data analysis suite that integrates, among many other algorithms, the most common steps of a SNP association study. It frees the user from the need to have large computer facilities and an in depth knowledge of genetic software installation and management. Genotype data is directly read from the output files of the usual genotyping platforms. Phenotypic data on the samples can also be easily uploaded. Many different quality control and analysis procedures can be performed either by using built-in SNPator algorithms or by calling standard genetic software. AVAILABILITY: Access is granted from the SNPator webpage http://www.snpator.org.     

An Internet‐based platform for the estimation of outcrossing potential between cultivated and Chilean vascular plants

A national‐scale study of outcrossing potential within Chilean vascular flora was conducted using an upgraded algorithm, which adds parameters such as pollinator agents, climate, and geographic conditions. Datasets were organized and linked in a Web platform ( www.flujogenico.cl ), in which the development of a total outcrossing potential (TOP) predictor was formulated. The TOP predictor is the engine in the Web platform, which models the effect of a type of agricultural practice on others (coexistence calculation mode) and on the environment (biodiversity calculation mode). The scale for TOP results uses quintiles in order to define outcrossing potential between species as “very low,” “low,” “medium,” “high,” or “very high.” In a coexistence analysis considering 256 species (207 genera), the 10 highest TOP values were for genera Citrus, Prunus, Trifolium, Brassica, Allium, Eucalyptus, Cucurbita, Solanum, Lollium, and Lotus. The highest TOP for species in this analysis fell at “high” potential, 4.9% of the determined values. In biodiversity mode, seven out of 256 cultivated species (2.7%) were native, and 249 (97.3%) corresponded to introduced species. The highest TOP was obtained in the genera Senecio, Calceolaria, Viola, Solanum, Poa, Alstroemeria, Valeriana, Vicia, Atriplex, and Campanula, showing “high” potential in 4.9% of the values. On the other hand, 137 genetically modified species, including the commercial and pre‐commercial developments, were included and represented 100 genera. Among these, 22 genera had relatives (i.e., members of the same genus) in the native/introduced group. The genera with the highest number of native/introduced relatives ranged from one (Ipomea, Limonium, Carica, Potentilla, Lotus, Castanea, and Daucus) to 66 species (Solanum). The highest TOP was obtained when the same species were coincident in both groups, such as for Carica chilensis, Prosopis tamarugo, and Solanum tuberosum. Results are discussed from the perspective of assessing the possible impact of cultivated species on Chilean flora biodiversity. The TOP predictor ( http://epc.agroinformatica.cl/ ) is useful in the context of environmental risk assessment.     

The forest-cerrado transition zone in southern Amazonia: Results of the 1985 Projeto Flora Amazônica expedition to Mato Grosso

An account of the history of collecting in the Mato Grosso is followed by a discussion of the current views on the nature of the vegetation along the transition from Amazonian forest to cerrado. The purpose of the 1985 Projeto Flora Amazônica expedition was to sample the vegetation in the transition region in northern Mato Grosso. In order to characterize the vegetation at the various localities, the identified collections were assigned to one of five broad distributional categories: Planaltine, Transitional, Amazonian, Wide-spread, or Other. In most cases, as expected, the collecting sites in the north and the west were characterized by Amazonian forest species while those in the south and east comprised mainly cerrado elements. Our collections show that the transition zone is a complex mosaic of Amazonian forest and cerrado formations.     

The amino-terminal non-catalytic region of Salmonella typhimurium SigD affects actin organization in yeast and mammalian cells

The internalization of Salmonella into epithelial cells relies on the function of bacterial proteins which are injected into the cell by a specialized type III secretion system. Such bacterial effectors interfere with host cell signalling and induce local cytoskeletal rearrangements. One of such effectors is SigD/SopB, which shares homology with mammalian inositol phosphatases. We made use of the Saccharomyces cerevisiae model for elucidating new aspects of SigD function. Endogenous expression of SigD in yeast caused severe growth inhibition. Surprisingly, sigD alleles mutated in the catalytic site or even deleted for the whole C-terminal phosphatase domain still inhibited yeast growth by inducing loss of actin polarization and precluding the budding process. Accordingly, when expressed in HeLa cells, the same sigD alleles lost the ability of depleting phosphatidylinositol 4,5-bisphosphate from the plasma membrane, but still caused disappearance of actin fibres and loss of adherence. We delineate a region of 25 amino acids (residues 118-142) that is necessary for the effect of SigD on actin in HeLa cells. Our data indicate that SigD exerts a toxic effect linked to its N-terminal region and independent of its phosphatase activity.     

Draft genome sequences of bacteria isolated from the Deschampsia antarctica phyllosphere

Extremophiles - Genome analyses are being used to characterize plant growth-promoting (PGP) bacteria living in different plant compartiments. In this context, we have recently isolated bacteria...     

Viability of starved Pasteurella piscicida in seawater monitored by flow cytometry and the effect of antibiotics on its resuscitation

The viability of starved Pasteurella piscicida cells in seawater was analysed by flow cytometry using two fluorescent dyes that stain only living cells. The fluorescent histograms using rhodamine 123 showed that, during the total experimental period, a considerable proportion of cells were able to incorporate this fluorochrome. In addition, the assays employing propidium iodide as dye, demonstrated that the Past. piscicida cells remained viable, maintaining their cellular integrity. Chloramphenicol or ampicillin totally inhibited the resuscitation of non-culturable cells when they were added 8 and 24 h after the incorporation of fresh medium to the microcosms, but had practically no effect after 48 h when cells were fully resuscitated, indicating that active protein and peptidoglycan synthesis were ongoing during all stages of resuscitation.     

Evaluation of chlorophyll fluorescence as a tool for salt stress detection in roses

The induction kinetic of the chlorophyll (Chl) fluorescence and the F_v/F_m ratio have been tested in order to find out the suitability of this technique to evaluate damage caused by salinity in plants of Rosa hybrida cv. Ilseta grafted on R. manetti growing in a greenhouse under non-saturating irradiance. Under these conditions salinity induced changes in plants morphology, nutrient and Chl contents and in the gas exchange parameters, but not in the F_v/F_m ratio. The Rfd index did not reveal more information. The F_v/F_m ratio as well as the fluorescence induction curves were more affected by salinity when an irradiation stress was added, therefore as an indicator of salt stress in roses, Chl fluorescence is of limited use when the plants are grown without additional stress. This revised version was published online in August 2006 with corrections to the Cover Date.