3-Hydroxypropionic Acid as an Antibacterial Agent from Endophytic Fungi Diaporthe phaseolorum

Endophytic fungi are considered a rich source of active compounds resulting from their secondary metabolism. Fungi from marine environment grow in a habitat with unique conditions that can contribute to the activation of metabolic pathways of synthesis of different unknown molecules. The production of these compounds may support the adaptation and survival of the fungi in the marine ecosystem. Mangroves are ecosystems situated between land and sea. They are frequently found in tropical and subtropical areas and enclose approximately 18.1 million hectares of the planet. The great biodiversity found in these ecosystems shows the importance of researching them, including studies regarding new compounds derived from the endophytic fungi that inhabit these ecosystems. 3-hydroxypropionic acid (3-HPA) has been isolated from the mangrove endophytic fungus Diaporthe phaseolorum, which was obtained from branches of Laguncularia racemosa. The structure of this compound was elucidated by spectroscopic methods, mainly 1D and 2D NMR. In bioassays, 3-HPA showed antimicrobial activities against both Staphylococcus aureus and Salmonella typhi. The structure of this antibiotic was modified by the chemical reaction of Fischer-Speier esterification to evaluate the biologic activity of its chemical analog. The esterified product, 3-hydroxypropanoic ethyl ester, did not exhibit antibiotic activity, suggesting that the free carboxylic acid group is important to the pharmacological activity. The antibiotic-producing strain was identified with internal transcribed spacer sequence data. To the best of our knowledge, this is the first report of antibacterial activity by 3-HPA against the growth of medically important pathogens.

Carboxymethyl lignin as stabilizing agent in aqueous ceramic suspensions

Identifying new uses for residues of industries that process large quantities of biomass, as in bioethanol production, is essential for a sustainable development with reduced impact on the environment, which is the reason why many efforts have been devoted to find noble uses for lignins. in this study, a lignin obtained from sugarcane bagasse in a bioethanol producing plant was carboxymethylated to yield the water-soluble carboxymethyl lignin (CML), which was then used as stabilizing agent in aqueous alumina (Al2O3) suspensions. CML had a degree of substitution 0.46 +/- 0.01, in relation to the C9 unit of lignin, and behaved as a polyelectrolyte in a large pH range owing to the dissociation of carboxylic groups. The action of CML as stabilizing agent of alumina aqueous suspensions was investigated using viscometry, zeta potential, and photon correlation spectroscopy (PCS) measurements, mainly as a function of pH and time. Overall, the results showed that CML had a good performance as a deflocculating agent, because it led to dispersions with low viscosity and small change in particle size as a function of time. The positive effect from the addition of CML was confirmed in the morphological features of the material obtained from the alumina suspensions after elimination of water, as indicated by scanning electron microscopy. The stabilization of alumina suspensions afforded by CML opens the way for similar applications of modified lignins, whose electrical and structural properties may be tuned for specific uses in various industries, including the ceramic industry. (C) 2011 Elsevier B.V. All rights reserved.

Dillapiole as Antileishmanial Agent: Discovery, Cytotoxic Activity and Preliminary SAR Studies of Dillapiole Analogues

In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structureactivity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC50?=?69.3 mu M) and Leishmania brasiliensis (IC50?=?59.4 mu M) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC50?=?99.9 mu M for L. amazonensis and IC50?=?90.5 mu M for L. braziliensis) and 3 (IC50?=?122.9 mu M for L. amazonensis and IC50?=?109.8 mu M for L. brasiliensis) were less active than dillapiole (1). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues.

Searching for resonances in the unbound Be-6 nucleus by using a radioactive Be-7 beam

Knowledge of the He-3(He-3,2p)He-4 reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low-energy resonance in the He-3 + He-3 (Be-6) system or electron screening. In the Be-6 nucleus, however, no excited states have been observed above the first 2(+) state at E (x) = 1.67 MeV up to 23 MeV, even though several are expected. The H-2(Be-7,H-3)Be-6 reaction has been studied for the first time to search for resonances in the Be-6 nucleus that may affect our understanding of the He-3(He-3,2p)He-4 reaction. A 100-MeV radioactive Be-7 beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD2 targets, and tritons were detected by using the silicon detector array (SIDAR). A combination of reaction mechanisms appears to be necessary to explain the observed triton energy spectrum.

Experimental infection of the tick Amblyomma cajennense, Cayenne tick, with Rickettsia rickettsii, the agent of Rocky Mountain spotted fever

In the laboratory, Amblyomma cajennense (Acari: Ixodidae) (Fabricius) larvae, nymphs and adults were exposed to Rickettsia rickettsii by feeding on needle-inoculated animals, and thereafter reared on uninfected guinea pigs or rabbits. Regardless of the tick stage that acquired the infection, subsequent tick stages were shown to be infected (confirming transstadial and transovarial transmissions) and were able to transmit R. rickettsii to uninfected animals, as demonstrated by serological and molecular analyses. However, the larval, nymphal and adult stages of A. cajennense were shown to be partially refractory to R. rickettsii infection, as in all cases, only part of the ticks became infected by this agent, after being exposed to rickettsemic animals. In addition, less than 50% of the infected engorged females transmitted rickettsiae transovarially, and when they did so, only part of the offspring became infected, indicating that vertical transmission alone is not enough to maintain R. rickettsii in A. cajennense for multiple generations. Finally, the R. rickettsii-infected tick groups had lower reproductive performance than the uninfected control group. Our results indicate that A. cajennense have a low efficiency to maintain R. rickettsii for successive generations, as R. rickettsii-infection rates should decline drastically throughout the successive tick generations.

Improving the performance of a glucose biosensor using an ionic liquid for enzyme immobilization. On the chemical interaction between the biomolecule, the ionic liquid and the cross-linking agent

The effect of the room temperature ionic liquid (1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BMMI][BF4])) on the immobilization of glucose oxidase (GOx) was studied. The electrochemical performance of biosensors prepared following different protocols indicated a beneficial effect of the ionic liquid on the analytical parameters. The chemical interaction between GOx, [BMMI][BF4] and glutaraldehyde was investigated using UV-visible spectroscopy (UV-vis) and circular dichroism (CD). Structural changes of the biomolecule were observed to depend on the method used for the immobilization. (C) 2011 Elsevier Ltd. All rights reserved.

Chemical mechanism of controlled nitric oxide release from trans-[RuCl([15]aneN(4))NO](PF6)(2) as a vasorelaxant agent

The nitrosyl ruthenium complex, trans-[RuCl([15]aneN(4))NO](PF6)(2), ([15]aneN(4) = 1,4,8,12-tetraazacyclopentadecane), exhibits vasorelaxation characteristics attributed to its nitric oxide release properties. The observed in vitro and in vivo vasodilation is dependent on noradrenaline concentration. We report here the chemical mechanism of the reaction between noradrenaline and trans-[RuCl([15]aneN(4))NO](PF6)(2) in aqueous phosphate buffer solution at pH 7.40. NO measurement by NO-sensor electrode, cyclic voltammetry, (PNMR)-P-31 and HPLC analysis were used to investigate the reduction process as the fundamental step for NO release characteristic of trans-[RuCl([15]aneN(4))NO](PF6)(2). A supramolecular species containing HPO4 (2-) as a bridging group between noradrenaline and trans-[RuCl([15]aneN(4))NO](PF6)(2) is suggested as an intermediate prior to the reduction of the nitrosyl ruthenium complex.

Metacontingencies, Experimentation and Nonhumans: Searching for Conceptual and Methodological Advances

Metacontingency has been described as the functional relation between interlocking behavioral contingencies, plus their direct and immediate effect, called aggregated product, and a selecting event dependent of such effect, called cultural consequence. The metacontingencies analysis enables the discussion of human behavior complexity in social systems. In the present study, we aimed to review and discuss: (a) the importance of basic behavioral processes analysis for the comprehension of social human phenomena; (b) the necessity of constructing and improving metacontingencies experimental models; (c) the current state of metacontingencies experimental investigations in humans; (d) the use of animal models as a way to control the effects of verbal behavior, among other variables, over cultural selection; (e) a concrete and illustrative proposal of an animal model of metacontingencies.

RNA Interference of Endochitinases in the Sugarcane Endophyte Trichoderma virens 223 Reduces Its Fitness as a Biocontrol Agent of Pineapple Disease

The sugarcane root endophyte Trichoderma virens 223 holds enormous potential as a sustainable alternative to chemical pesticides in the control of sugarcane diseases. Its efficacy as a biocontrol agent is thought to be associated with its production of chitinase enzymes, including N-acetyl-beta-D-glucosaminidases, chitobiosidases and endochitinases. We used targeted gene deletion and RNA-dependent gene silencing strategies to disrupt N-acetyl-beta-D-glucosaminidase and endochitinase activities of the fungus, and to determine their roles in the biocontrol of soil-borne plant pathogens. The loss of N-acetyl-beta-D-glucosaminidase activities was dispensable for biocontrol of the plurivorous damping-off pathogens Rhizoctonia solani and Sclerotinia sclerotiorum, and of the sugarcane pathogen Ceratocystis paradoxa, the causal agent of pineapple disease. Similarly, suppression of endochitinase activities had no effect on R. solani and S. sclerotiorum disease control, but had a pronounced effect on the ability of T. virens 223 to control pineapple disease. Our work demonstrates a critical requirement for T. virens 223 endochitinase activity in the biocontrol of C. paradoxa sugarcane disease, but not for general antagonism of other soil pathogens. This may reflect its lifestyle as a sugarcane root endophyte.

Morphological Homogeneity of Neurons: Searching for Outlier Neuronal Cells

We report a morphology-based approach for the automatic identification of outlier neurons, as well as its application to the NeuroMorpho.org database, with more than 5,000 neurons. Each neuron in a given analysis is represented by a feature vector composed of 20 measurements, which are then projected into a two-dimensional space by applying principal component analysis. Bivariate kernel density estimation is then used to obtain the probability distribution for the group of cells, so that the cells with highest probabilities are understood as archetypes while those with the smallest probabilities are classified as outliers. The potential of the methodology is illustrated in several cases involving uniform cell types as well as cell types for specific animal species. The results provide insights regarding the distribution of cells, yielding single and multi-variate clusters, and they suggest that outlier cells tend to be more planar and tortuous. The proposed methodology can be used in several situations involving one or more categories of cells, as well as for detection of new categories and possible artifacts.

Exploration of the parameter space in an agent-based model of tuberculosis spread: emergence of drug resistance in developing vs developed countries

In this work we present an agent-based model for the spread of tuberculosis where the individuals can be infected with either drug-susceptible or drug-resistant strains and can also receive a treatment. The dynamics of the model and the role of each one of the parameters are explained. The whole set of parameters is explored to check their importance in the numerical simulation results. The model captures the beneficial impact of the adequate treatment on the prevalence of tuberculosis. Nevertheless, depending on the treatment parameters range, it also captures the emergence of drug resistance. Drug resistance emergence is particularly likely to occur for parameter values corresponding to less efficacious treatment, as usually found in developing countries.

How promising is Lasioseius floridensis as a control agent of Polyphagotarsonemus latus?

The blattisociid mite Lasioseius floridensis Berlese was found associated with the broad mite, Polyphagotarsonemus latus (Banks), on gerbera leaves in Mogi das Cruzes, State of Sao Paulo, Brazil. Blattisociid mites are not common on aerial plant parts, except under high air humidity levels. Some Lasioseius species have been mentioned as effective control agents of rice pest mites, but nothing is known about the biology of L. floridensis. The objective of this study was to evaluate whether the observed co-occurrence of L. floridensis and P. latus was just occasional or whether the latter could be important as food source for the former, assumed by laboratory evaluation of the ability of the predator to maintain itself, reproduce and develop on that prey. Biological parameters of L. floridensis were compared when exposed to P. latus and to other items as food. The study showed that mating is a pre-requisite for L. floridensis to oviposit and that oviposition rate was much higher on the soil nematode Rhabditella axei (Cobbold) (Rhabditidae) than on P. latus. Ovipositon on the acarid mite Tyrophagus putrescentiae (Schrank) was about the same as on P. latus, but it was nearly zero when the predator was fed the fungi Aspergillus flavus Link or Penicillium sp., or cattail (Typha sp.) pollen. Survivorship was higher in the presence of pollen and lower in the presence of A. flavus or Penicillium sp. than in the absence of those types of food. Life table parameters indicated that the predator performed much better on R. axei than on P. latus. To evaluate the potential effect of L. floridensis as predator of P. latus, complementary studies are warranted to determine the frequency of migration of L. floridensis to aerial plant parts, when predation on P. latus could occur.

Neospora caninum as causative agent of bovine encephalitis in Brazil

For supporting the Brazilian bovine encephalitis surveillance program this study examined the differential diagnosis of Neospora caninum in central nervous system (CNS) by histological analysis (HE staining), immunohistochemistry (IHC), and nested-PCR using a set of primers from the Nc5 region of the genomic DNA and ITS1 region of the ribosomal DNA. A sample of 302 cattle presenting neurological syndrome and negative for rabies, aged 0 to 18 years, from herds in 10 Brazilian states was evaluated for N caninum from January 2007 to April 2010. All specimens tested negative with IHC and nested-PCR using primers from the ITS I region of ribosomal DNA, while two positive cases (0.66%) were found using primers from the Nc5 region of genomic DNA: a 20 month-old male and a 72 month-old female, both from Sao Paulo State. Only the male presented severe multifocal necrotizing encephalitis associated with mononuclear cell infiltration, a pathognomonic lesion caused by parasites of the family Sarcocystidae, and only this case was associated with N caninum thus representing 0.33% positivity. Future studies should explore the association of IHC and nested-PCR with real-time PCR, a quantitative method that could be standardized for improving the detection of N. caninum in bovine CNS specimens.

Searching for the first stars with the Gaia mission

Aims. We construct a theoretical model to predict the number of orphan afterglows (OA) from gamma-ray bursts (GRBs) triggered by primordial metal-free (Pop III) stars expected to be observed by the Gaia mission. In particular, we consider primordial metal-free stars that were affected by radiation from other stars (Pop III. 2) as a possible target. Methods. We use a semi-analytical approach that includes all relevant feedback effects to construct cosmic star formation history and its connection with the cumulative number of GRBs. The OA events are generated using the Monte Carlo method, and realistic simulations of Gaia's scanning law are performed to derive the observation probability expectation. Results. We show that Gaia can observe up to 2.28 +/- 0.88 off-axis afterglows and 2.78 +/- 1.41 on-axis during the five-year nominal mission. This implies that a nonnegligible percentage of afterglows that may be observed by Gaia (similar to 10%) could have Pop III stars as progenitors.

Diametral tensile strength and film thickness of an experimental dental luting agent derived from castor oil

The need to develop new dental luting agents in order to improve the success of treatments has greatly motivated research. Objective: The aim of this study was to evaluate the diametral tensile strength (DTS) and film thickness (FT) of an experimental dental luting agent derived from castor oil (COP) with or without addition of different quantities of filler (calcium carbonate - CaCO3). Material and Methods: Eighty specimens were manufactured (DTS N=40; FT N=40) and divided into 4 groups: Pure COP; COP 10%; COP 50% and zinc phosphate (control). The cements were mixed according to the manufacturers' recommendations and submitted to the tests. The DTS test was performed in the MTS 810 testing machine (10 KN, 0.5 mm/min). For FT test, the cements were sandwiched between two glass plates (2 cm(2)) and a load of 15 kg was applied vertically on the top of the specimen for 10 min. The data were analyzed by means of one-way ANOVA and Tukey's test (alpha=0.05). Results: The values of DTS (MPa) were: Pure COP- 10.94 +/- 1.30; COP 10%- 30.06 +/- 0.64; COP 50%- 29.87 +/- 0.27; zinc phosphate- 4.88 +/- 0.96. The values of FT (pm) were: Pure COP- 31.09 +/- 3.16; COP 10%- 17.05 +/- 4.83; COP 50%- 13.03 +/- 4.83; Zinc Phosphate- 20.00 +/- 0.12. One-way ANOVA showed statistically significant differences among the groups (DTS - p=1.01E-40; FT - p=2.4E-10). Conclusion: The experimental dental luting agent with 50% of filler showed the best diametral tensile strength and film thickness.