Quinolizidine alkaloids in Ormosia arborea seeds inhibit predation but not hoarding by agoutis (Dasyprocta leporina)

Quinolizidine alkaloids (QAs) are secondary compounds found in seeds of many species of plants, possibly protecting them against pathogens and seed predators. QAs were isolated from Ormosia arborea seeds and bioassayed against red-rumped agoutis (Dasyprocta leporina, Rodentia: Caviomorpha) to verify if they inhibit seed predation and food hoarding (seed dispersal). Three treatments were used: (1) seeds of O. arborea, (2) palatable seeds of Mimusops coriacea (Sapotaceae) treated with MeOH, and (3) seeds of M. coriacea treated with QAs dissolved in MeOH in similar concentration to that present in O. arborea. Palatable seeds were significantly more preyed upon than seeds treated with QAs and Ormosia seeds, but QAs did not influence hoarding behavior. QAs in O. arborea may have a strong effect in avoiding seed predation by rodents, without reducing dispersal.     

Biocompatibility and adsorption properties of hydrogels obtained by graft polymerization of acrylic acid on cellulose from rice hulls

Hydrogels constitute a group of cross-linked polymeric materials with the capability of swelling and retaining large amounts of water without dissolving. In this work, the hydrogels were obtained by grafting the acrylic acid on cellulose from rice hulls and cross-linking it with glycerol, ethylene glycol, and polyethylene glycol (M_w?=?200 and 10,000 g mol^?1). The samples were characterized using IR and Raman spectroscopy, the absence of the bands at 1636 and 1614 cm^?1 (in IR) and at 1659 and 1637 cm^?1 (in Raman), in the spectra of grafted cellulose and assigned to ν(C=C), indicated the polymerization process and the absence of the monomer residual. The cross-linking process was verified by the appearance of bands at 1090 cm^?1 (IR) and 996 cm^?1 (Raman), attributed to ν(C–O–C). Thermogravimetric analysis showed that the cross-linked sample with glycerol presented the lowest thermal stability. The molecular mass of CDClCC-g-AA was 55.56?±?5.21 kDa with an R² of 0.9741 and the CDClCC average particle size of 694 nm. The topography and the average roughness of the samples were obtained by atomic force microscopy and the samples that were cross-linked with the polyethylene glycol presented greater roughness. The degree of swelling was lower in the sample cross-linked with ethylene glycol, which was related to its higher degree of cross-linking. Finally, the biocompatibility of the samples was studied by analyzing the toxic effect of the samples on human embryonic kidney cells, where results showed that samples cross-linked with ethylene glycol were non-toxic.     

Intra-hippocampal administration of cycloheximide attenuates the restraint-induced exploratory deficit of an elevated plus maze

Rats submitted to 2 h of restraint stress show a reduced open arm exploration in the elevated plus maze 24 h later. The stress-induced exploratory deficit is prevented by i.c.v. pre-stress administration of cycloheximide (CHX), a protein synthesis inhibitor. The objective of the present work was to determine if the hippocampus could be involved in this effect. CHX (4 or 8 microg) was injected into the dorsal hippocampus of male Wistar rats (200-250 g), immediately before (n = 9-20 animals/group) a 2 h period of forced restraint. After 24 h the animals were tested in the elevated plus maze. Non-stressed, control groups, received saline (SAL) or cycloheximide (CHX, n = 6-12/group) and were tested 1 or 24 h later in the maze. Pre-stress microinjections of cycloheximide increased exploration of open arms in the elevated plus maze (percentage of entries, SAL = 10.3 +/- 2.7, CHX 4 microg = 24.5 +/- 4.6, CHX 8 microg = 28.2 +/- 4.8, percentage of time spent, SAL = 2.0 +/- 0.6, CHX 4 microg = 8.4 +/- 2.3, CHX 8 microg = 9.6 +/- 2.6, Duncan test, P < 0.05). No drug effect was observed in non stressed animals. These results suggest that blockade of protein synthesis in the dorsal hippocampus during the restraint period may attenuate the behavioural consequences of stress.     

Multi-objective approach for robot motion planning in search tasks

This work addresses the problem of single robot coverage and exploration in an environment with the goal of finding a specific object previously known to the robot. As limited time is a constraint of interest we cannot search from an infinite number of points. Thus, we propose a multi-objective approach for such search tasks in which we first search for a good set of positions to place the robot sensors in order to acquire information from the environment and to locate the desired object. Given the interesting properties of the Generalized Voronoi Diagram, we restrict the candidate search points along this roadmap. We redefine the problem of finding these search points as a multi-objective optimization one. NSGA-II is used as the search engine and ELECTRE I is applied as a decision making tool to decide among the trade-off alternatives. We also solve a Chinese Postman Problem to optimize the path followed by the robot in order to visit the computed search points. Simulation results show a comparison between the solution found by our method and solutions defined by other known approaches. Finally, a real robot experiment indicates the applicability of our method in practical scenarios.     

Brazil’s growing production of scientific articles—how are we doing with review articles and other qualitative indicators?

This article identifies scientific fields in Brazil that have been generating new knowledge, their evolution, tendencies and the relationship between scientific production and the National Postgraduate Program (Programa Nacional de Pós-Graduação—PNPG). It works with review articles and assesses: (a) articles published as reviews by international databases; (b) the growth of Brazilian participation in that context; (c) institutional participation; (d) the predominant fields of knowledge; (e) the most productive authors, and (f) periodicals that published the greatest number of review articles by Brazilian authors. The 5,348 review articles published between 2000 and 2009 were made available in 1,309 scientific publications, and the fields that published the most reviews were Pharmacology, Chemistry, Neurosciences, Biochemistry and Molecular Biology, Psychiatry, Neurology, Endocrinology and Internal Medicine. The reviews were produced by 27,096 authors under the auspices of 20 institutions which, together, answer for 95 % of the Brazilian production, and are public, excepting for the Pontifícia Universidade Católica do Rio Grande do Sul (PUC-RS). In the international scenario, we find that 31 countries are responsible for 90.11 % of the total scientific production and 94.08 % of the review articles. To establish a comparison between Brazil and its closest competitors, these countries can be classified arbitrarily in three groups: (1) countries with a large number of review articles (>3100), an average number of citations above 18, and an h-index greater than 95; (2) countries with a significant production of articles (between 2,000 and 3,000), average number of citations between 12 and 17, and an h-index below 95. Brazil is in the third group, (3) formed by countries with a lower level of production and the two qualitative indicators at opposite poles: the average of citations on a par with the first group (>18) and h-indexes like those of the second group (<95).     

Sheep milk kefir sweetened with different sugars: Sensory acceptance and consumer emotion profiling

The objective of this study was to determine the sensory acceptance and emotional profile of sheep milk kefir sweetened with different sugars (demerara sugar, brown sugar, fructose, coconut sugar, and honey, 100 g/L). Consumers (n = 100) assessed sensory acceptance (appearance, aroma, taste, texture, and overall impression), and expressed their emotions (satisfied, active, loving, calm, comfortable, energetic, happy, healthy, refreshing, disgusted, worried, and upset). The emotions “satisfied,” “active,” “comfortable,” “energetic,” “healthy,” and “refreshing” were found between moderate and very high levels, indicating that they are important emotions for the characterization and sensory acceptance of kefir samples. The use of different sugars had no influence on the intensity of the emotions “calm,” “comfortable,” “happy,” or “disgusted,” and resulted in a greater sense of satisfaction. The use of demerara sugar or fructose did not alter the acceptance of the products or the intensity of emotions. The use of brown sugar decreased acceptance (taste, texture, and overall impression) and the intensity of the emotions “active,” “loving,” “energetic,” “healthy,” and “refreshing.” The use of coconut sugar decreased acceptance (appearance, aroma, and taste) and the intensity of the emotions “refreshing” and “upset.” The use of honey improved acceptance in appearance and aroma but reduced the intensity of the emotions “active,” “loving,” “energetic,” and “healthy.” Based on sensory data, it is recommended to use demerara sugar or fructose as a substitute for sucrose. In conclusion, the study of emotions can be used as an additional tool for obtaining data related to the sensory acceptance of products.     

Toxigenic status of Staphylococcus aureus isolated from bovine raw milk and Minas frescal cheese in Brazil

A group of 291 Staphylococcus aureus isolates from mastitic cow's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the S. aureus isolates bearing SE genes, 17 (13.6%) were from mastitic cow's milk, 41 (41.7%) were from bulk tank milk, and 51 (72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described SE genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical SE genes (sea through see, 15 strains). The SE genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic cow's milk. Macrorestriction analysis of chromosomal DNA from 89 S. aureus isolates positive for SE gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, Apa I, used for some isolates was less discriminating than Sma I. The high genotype diversity of potential toxigenic S. aureus strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety.