Performance and molecular evaluation of an anaerobic system with suspended biomass for treating wastewater with high fat content after enzymatic hydrolysis

The effect of a lipase-rich fungal enzymatic preparation, produced by a Penicillium sp. during solid-state fermentation, was evaluated in an anaerobic digester treating dairy wastewater with 1200 mg of oil and grease/L The oil and grease hydrolysis step was carried out with 0.1% (w/v) of solid enzymatic preparation at 30 degrees C for 24 h, and resulted in a final free acid concentration eight times higher than the initial value. The digester operated in sequential batches of 48 h at 30 degrees C for 245 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. However, when the pre-hydrolysis step was removed, the anaerobic digester performed poorly (with an average COD removal of 32%), as the oil and grease accumulated in the biomass and effluent oil and grease concentration increased throughout the operational period. PCR-DGGE analysis of the Bacteria and Archaea domains revealed remarkable differences in the microbial profiles in trials conducted with and without the pre-hydrolysis step, indicating that differences observed in overall parameters were intrinsically related to the microbial diversity of the anaerobic sludge. (C) 2009 Elsevier Ltd. All rights reserved.

Backside contact effect on the morphological and optical features of porous silicon photonic crystals

The present work reports on the effect of the type of backside contact used in the electrochemical process and their relation with the structural features and optical responses of the one-dimensional photonic crystal (PC) anodized in simple and double electrochemical cell. The PC, obtained in the single cell, showed to have thicker layers than of the PC obtained in double electrochemical cell. Additionally, the PC obtained in double cell showed highest reflectance in the band gap region than of the PCs obtained in single cell. These results suggest that the interface roughness between adjacent layers in the PC devices obtained in double electrochemical cell is minimized. (C) 2008 Elsevier Ltd. All rights reserved.

Isolation and characterization of actinobacteria ectosymbionts from Acromyrmex subterraneus brunneus (Hymenoptera, Formicidae)

The ectosymbiont actinobacterium Pseudonocardia was isolated from the integument of Acromyrmex leaf-cutter ants and seems to play a crucial role in maintaining asepsis of the nest. Currently, there has been an intensive search for Pseudonocardia associated with several attine species, but few studies have indicated that other actinobacteria may be associated with these ants as well. We therefore characterized the culturable actinobacteria community associated with the integument of the fungus-growing ant Acromyrmex subterraneus brunneus Forel, 1893 (Hymenoptera: Formicidae). Ectosymbionts were isolated using four different media and characterized by morphological and molecular (16S rDNA) methods. A total of 20 strains were isolated, of which 17 were characterized as Streptomyces spp., and one isolate each as Pseudonocardia, Kitassatospora and Propionicimonas. Unlike other Acromyrmex species, A. subterraneus brunneus is associated with a diversity of actinobacteria. Even though Pseudonocardia is present on this leaf-cutting ant`s integument, the number and diversity of Streptomyces spp. found differs from those of previous studies with other attine ants and suggest that different culturing approaches are needed to characterize the true diversity of microbes colonizing the integument of attine ants. Moreover, understanding the diversity of the culturable actinobacteria associated with A. subterraneus brunneus should increase our knowledge of the evolutionary relationship of this intricate symbiotic association. (C) 2010 Elsevier GmbH. All rights reserved.

Reproductive Activity and Survivorship of Liriomyza sativae (Diptera: Agromyzidae) at Different Temperatures and Relative Humidity Levels

We studied a population of Liriomyza sativae Blanchard (Diptera: Agromyzidae) identified by morphological and molecular techniques from the semiarid region of the Brazilian northeast. The influence of temperature and relative humidity on the survival and reproductive parameters of L. sativae in cowpeas (Vigna unguiculata L. Walp.) (Fabales: Fabaceae) was evaluated. We used temperatures of 18, 20, 22, 25, 28, 30, and 32 +/- 1 degrees C (50 +/- 10% RH) and relative humidity values of 30,50,70, and 90 +/- 10% (25 +/- 1 degrees C) under a 14 L:10 D photoperiod. Adult longevity decreased as temperature and relative humidity increased and was greater, in general, for females. The preoviposition and oviposition periods also decreased as temperature increased, whereas relative humidity only caused reductions in the oviposition period at higher levels. Fecundity was similar in the range from 18 to 30 degrees C but decreased at 32 degrees C with respect to relative humidity; the best performances of L. sativae occurred at lower levels. The pattern of oviposition rate changed with temperature and relative humidity. Regardless of temperature and relative humidity, L, sativae laid between 75 and 92% of its eggs on the adaxial surface of the cowpea leaves. This information will be highly useful to design a leafminer production system aimed at the multiplication of natural enemies, as well as for pest management in the field.

Localization of Pantoea ananatis inside lesions of maize White Spot Disease using transmission electron microscopy and molecular techniques

The etiological agent of maize white spot (MWS) disease has been a subject of controversy and discussion. Initially the disease was described as Phaeosphaeria leaf spot caused by Phaeosphaeria maydis. Other authors have Suggested the existence of different fungal species causing similar symptoms. Recently, a bacterium, Pantoea ananatis, was described as the causal agent of this disease. The purpose of this Study was to offer additional information on the correct etiology of this disease by providing visual evidence of the presence of the bacterium in the interior of the MWS lesions by using transmission electron microscopy (TEM) and molecular techniques. The TEM allowed Visualization of a large amount of bacteria in the intercellular spaces of lesions collected from both artificially and naturally infected plants. Fungal structures were not visualized in young lesions. Bacterial primers for the 16S rRNA and rpoB genes were used in PCR reactions to amplify DNA extracted from water-soaked (young) and necrotic lesions. The universal fungal oligonucleotide ITS4 was also included to identity the possible presence of fungal structures inside lesions. Positive PCR products from water-soaked lesions, both from naturally and artificially inoculated plants, were produced with bacterial primers, whereas no amplification was observed when ITS4 oligonucleotide was used. On the other hand, DNA amplification with ITS4 primer was observed when DNA was isolated from necrotic (old) lesions. These results reinforced previous report of P. ananatis as the primary pathogen and the hypothesis that fungal species may colonize lesions pre-established by P. ananatis.

Histological, physiological and molecular investigations of Fagus sylvatica seedlings infected with Phytophthora citricola

P>The aim of the work was to shed light into histological, physiological and molecular changes of Fagus sylvatica seedlings infected with the root pathogen Phytophthora citricola with the final goal to distinguish between local and systemic responses. Real-time quantitative PCR analysis proved that P. citricola was able to grow from infected roots into hypocotyl and epicotyl tissue of F. sylvatica seedlings. Light microscopy showed many collapsed parenchyma cells of the cortex without being penetrated by the pathogen. Hyphae were mainly growing intracellular in parenchyma and xylem tissue. Transmission electron microscopy displayed disintegration of xylem vessels and of parenchyma cells. Inhibition of water uptake of infected beech seedlings was positively correlated with the concentration of zoospores used in the experiment. In addition, a split root experiment indicated that invertases were possibly involved locally and systemically in the conversion of sucrose of P. citricola infected roots. During the growth of the pathogen in roots, a transient expression of the 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidase gene was quantified in leaves which was detected in parallel with the first peak of a biphasic ethylene outburst. Additionally a systemic upregulation of aquaporin transcripts was mainly detected in leaves of beech seedlings infected with P. citricola.

Host-guest complexation of a nitroheterocyclic compound with cyclodextrins: a spectrofluorimetric and molecular modeling study

Nitroheterocyclic compounds (NC) were candidate drugs proposed for Chagas disease chemotherapy. In this study, we investigated the complexation of hydroxymethylnitrofurazone (NFOH), a potential antichagasic compound, with alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), Hydroxypropyl-beta-cyclodextrin (HP-beta-CD), Dimethyl-beta-cyclodextrin (DM-beta-CD) and gamma-cyclodextrin (gamma-CD) by fluorescence spectroscopy and molecular modeling studies. Hildebrand-Benesi equation was used to calculate the formation constants of NFOH with cyclodextrins based on the fluorescence differences in the CDs solution. The complexing capacity of NFOH with different CDs was compared through the results of association constant according to the following order: DM-beta-CD > beta-CD > alpha-CD > HP-beta-CD > gamma-CD. Molecular modeling studies give support for the experimental assignments, in favor of the formation of an inclusion complex between cyclodextrins with NFOH. This is an important study to investigate the effects of different kinds of cyclodextrins on the inclusion complex formation with NFOH and to better characterize a potential formulations to be used as therapeutic options for the oral treatment of Chagas disease.

Design, synthesis, antimicrobial activity and molecular modeling studies of novel benzofuroxan derivatives against Staphylococcus aureus

Molecular modi. cation is a quite promising strategy in the design and development of drug analogs with better bioavailability, higher intrinsic activity and less toxicity. In the search of new leads with potential antimicrobial activity, a new series of 14 4-substituted [N`-(benzofuroxan-5-yl) methylene] benzohydrazides, nifuroxazide derivatives, were synthesized and tested against standard and multidrug-resistant Staphylococcus aureus strains. The selection of the substituent groups was based on physicochemical properties, such as hydrophobicity and electronic effect. These properties were also evaluated through the lipophilic and electrostatic potential maps, respectively, considering the compounds with better biological pro. le. Twelve compounds exhibited similar bacteriostatic activity against standard and multidrug-resistant strains. The most active compound was the 4-CF(3) substituted derivative, which presented a minimum inhibitory concentration (MIC) value of 14.6-13.1 mu g/mL, and a ClogP value of 1.87. The results highlight the benzofuroxan derivatives as potential leads for designing new future antimicrobial drug candidates. (C) 2009 Elsevier Ltd. All rights reserved.

Crystal and molecular structures of dichloro((Z)-2-chloro-2-phenylvinyl)(organo)tellurium(IV) for organo = n-butyl and phenyl

In each of the title compounds, R[Ph(Cl)C=(H)C]TeCl(2), R = nBu (1) and Ph (2), the primary geometry about the Te(IV) atom is a pseudo-trigonal-bipyramidal arrangement, with two Cl atoms in apical positions, and the lone pair of electrons and C atoms in the equatorial plane. As the Te(IV) is involved in two, an intra- and an inter-molecular, Te center dot center dot center dot Cl interactions the coordination geometry might be considered as a Psi-pentagonal bipyramid in each case. In addition, in (2) there is a hint of a Te center dot center dot center dot pi interaction (Te center dot center dot center dot C = 3.911(3) A). The key feature in the crystal structure of both compounds is the formation of supramolecular chains mediated by Te center dot center dot center dot Cl contacts. (1): C(12)H(15)Cl(3)Te, triclinic, P (1) over bar, a = 5.9471 (11), b = 10.7826(22), c = 11.7983(19) angstrom, alpha = 75.416(12), beta = 78.868(13), gamma = 80.902(14)degrees, V = 713.6(2) angstrom(3), Z = 2, R(1) = 0.021; (2): C14HIIC13Te, orthorhombic, Pcab, a=7.7189(10), b=17.415(2), c=21.568(3)angstrom, V = 2899.3(6) angstrom(3), Z = 8, R(1) = 0.027.

Molecular dynamics, density functional, ADMET predictions, virtual screening, and molecular interaction field studies for identification and evaluation of novel potential CDK2 inhibitors in cancer therapy

In this work, we have used molecular dynamics, density functional theory, virtual screening, ADMET predictions, and molecular interaction field studies to design and propose eight novel potential inhibitors of CDK2. The eight molecules proposed showed interesting structural characteristics that are required for inhibiting the CDK2 activity and show potential as drug candidates for the treatment of cancer. The parameters related to the Rule of Five were calculated, and only one of the molecules violated more than one parameter. One of the proposals and one of the drug-like compounds selected by virtual screening indicated to be promising candidates for CDK2-based cancer therapy.

Use of virtual screening, flexible docking, and molecular interaction fields to design novel HMG-CoA reductase inhibitors for the treatment of hypercholesterolemia

Dietary changes associated with drug therapy can reduce high serum cholesterol levels and dramatically decrease the risk of coronary artery disease, stroke, and overall mortality. Statins are hypolipemic drugs that are effective in the reduction of cholesterol serum levels, attenuating cholesterol synthesis in liver by competitive inhibition regarding the substrate or molecular target HMG-CoA reductase. We have herewith used computer-aided molecular design tools, i.e., flexible docking, virtual screening in large data bases, molecular interaction fields to propose novel potential HMG-CoA reductase inhibitors that are promising for the treatment of hypercholesterolemia.

Evaluation of the Experimental Inoculation of Cryptococcus albidus and Cryptococcus laurentii in Normal Mice: Virulence Factors and Molecular Profile Before and After Animal Passage

The genus Cryptococcus includes free-developing species, a few of which are of medical importance. Some, such as C. neoformans and C. gattii, cause infections in man frequently and C. albidus and C. laurentii cause less so. The aims of this study were to evaluate organ colonization after inoculation of C. albidus and C. laurentii isolates in normal BALB/c mice, the virulence factors (growth at 37A degrees C, capsule, melanin, proteinase, and phospholipase production) and the molecular profile (PCR-fingerprinting) of the yeasts before and after infection. The importance of different profiles (virulence and molecular) was considered in relation to the distribution in different organs and to the time intervals of isolation from organs. C. albidus was isolated from animal organs 2 to 10 days after inoculation and C. laurentii from 2 to 120 days. Most isolates of the two species kept the virulence factors showed before inoculation. The high homogeneity of the molecular profile of C. albidus and the high heterogeneity of C. laurentii were kept through the passages in animals. It is concluded that most isolates of both species were recovered from the animal organs after 5 or more days, and phenotypes were not altered by inoculation. No molecular alteration was detected and the virulence factors were not related to the time intervals before isolation from organs.

Molecular dynamics, flexible docking, virtual screening, ADMET predictions, and molecular interaction field studies to design novel potential MAO-B inhibitors

Monoamine oxidase is a flavoenzyme bound to the mitochondrial outer membranes of the cells, which is responsible for the oxidative deamination of neurotransmitter and dietary amines. It has two distinct isozymic forms, designated MAO-A and MAO-B, each displaying different substrate and inhibitor specificities. They are the well-known targets for antidepressant, Parkinson`s disease, and neuroprotective drugs. Elucidation of the x-ray crystallographic structure of MAO-B has opened the way for the molecular modeling studies. In this work we have used molecular modeling, density functional theory with correlation, virtual screening, flexible docking, molecular dynamics, ADMET predictions, and molecular interaction field studies in order to design new molecules with potential higher selectivity and enzymatic inhibitory activity over MAO-B.

Regulation of xylanase in Aspergillus phoenicis: a physiological and molecular approach

Microbial xylanolytic enzymes have a promising biotechnological potential, and are extensively applied in industries. In this study, induction of xylanolytic activity was examined in Aspergillus phoenicis. Xylanase activity induced by xylan, xylose or beta-methylxyloside was predominantly extracellular (93-97%). Addition of 1% glucose to media supplemented with xylan or xylose repressed xylanase production. Glucose repression was alleviated by addition of cAMP or dibutyryl-cAMP. These physiological observations were supported by a Northern analysis using part of the xylanase gene ApXLN as a probe. Gene transcription was shown to be induced by xylan, xylose, and beta-methylxyloside, and was repressed by the addition of 1% glucose. Glucose repression was partially relieved by addition of cAMP or dibutyryl cAMP.

Morphological and morphometric appraisal of the spermatophore of the southern hermit crab Isocheles sawayai Forest and Saint Laurent, 1968 (Anomura: Diogenidae), with comments on gonopores in both sexes

The spermatophore morphology of the hermit crab Isocheles sawayai from Southwestern Atlantic (Brazil) is described. The spermatophores show similarities with those described for other members of the family Diogenidae, especially with the recently described Loxopagurus loxochelis. The spermatophore is composed of three major regions: a sperm filled head or ampulla, a columnar stalk and a foot or pedestal. The spermatophores show specific morphology in having a circular ampulla, and a constriction or neck between the ampulla (100 mu m) and the thin (27 mu m), long stalk (500 mu m). The stalk penetrates less than half way into the spermatophore head. Most spermatophores show one or the small posterior projections on the underside of the ampulla as being bigger than the other, making it asymmetrical. The size of the spermatophore is related to hermit crab size with direct relationships found between spermatophore ampulla width, total length, and peduncle length with shield length of the hermit crab. The morphological characteristics of the spermatophore of L sawayai. are species-specific distinguishing it from other members of the family, and are useful to infer further phylogenetic relationships. (C) 2008 Elsevier GmbH. All rights reserved.