Insecticidal and Repellent Activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus

This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.     

Evidence for kinetic and immunologic heterogeneity of dihydrofolate reductase in L1210 leukemia cells.

Two species of DHFR were identified in wild-type L1210 murine leukemia cells by analysis of the kinetics of the binding of MTX and dissociation of the MTX-enzyme complex at pH 5.0 and pH 7.2. The two forms of DHFR were also distinguished by immunoinhibition of the binding of MTX and the catalytic reduction of FH2 to FH4 using an antiserum raised to the purified high affinity form of DHFR. The Ka for the binding of MTX by the low affinity form of the enzyme is 4.5 x 10(7) M-1, substantially lower than the reported Ka for the binding of this drug by the high affinity enzyme. The low affinity form of the enzyme catalyzed the reduction of FH2 to FH4 at a rate slower than the high affinity form of DHFR.     

Effect of vitamin D3 on behavioural and biochemical parameters in diabetes type 1‐induced rats

Diabetes is associated with long‐term complications in the brain and reduced cognitive ability. Vitamin D₃ (VD₃) appears to be involved in the amelioration of hyperglycaemia in streptozotocin (STZ)‐induced diabetic rats. Our aim was to analyse the potential of VD₃ in avoiding brain damage through evaluation of acetylcholinesterase (AChE), Na⁺K⁺‐adenosine triphosphatase (ATPase) and delta aminolevulinate dehydratase (δ‐ALA‐D) activities and thiobarbituric acid reactive substance (TBARS) levels from cerebral cortex, as well as memory in STZ‐induced diabetic rats. Animals were divided into eight groups (n = 5): control/saline, control/metformin (Metf), control/VD₃, control/Metf + VD₃, diabetic/saline, diabetic/Metf, diabetic/VD₃ and diabetic/Metf + VD₃. Thirty days after treatment, animals were submitted to contextual fear‐conditioning and open‐field behavioural tests, after which they were sacrificed and the cerebral cortex was dissected. Our results demonstrate a significant memory deficit, an increase in AChE activity and TBARS levels and a decrease in δ‐ALA‐D and Na⁺K⁺‐ATPase activities in diabetic rats when compared with the controls. Treatment of diabetic rats with Metf and VD₃ prevented the increase in AChE activity when compared with the diabetic/saline group. In treated diabetic rats, the decrease in Na⁺K⁺‐ATPase was reverted when compared with non‐treated rats, but the increase in δ‐ALA‐D activity was not. VD₃ prevented diabetes‐induced TBARS level and improved memory. Our results show that VD₃ can avoid cognitive deficit through prevention of changes in important enzymes such as Na⁺K⁺‐ATPase and AChE in cerebral cortex in type 1 diabetic rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Endoparasites observed within invertebrates used as live food items for captive wild birds: Overview and potential risks

To monitor and evaluate potential risks to birds’ health, invertebrate species that have been used as live food items had their body contents searched for endoparasites. The contents of approximately 10,000 invertebrates were analyzed. A principal component analysis was performed to study the relationship between the presence/absence of endoparasites and the characteristics of the invertebrates. In most of them, including the species preferred by birds such as caterpillars, waxworms, mealworms, most grasshoppers, and spiders, no organism was identified. Such findings suggest a low potential for parasite transmission associated with its consumption by birds. Although they had unknown or even unlikely implications for the birds’ health, gregarines, oxyurides Leidynema sp., and digenetic trematodes Monolecithotrema sp. were found in samples from woodlice, cockroaches, and centipedes, respectively. The only avian parasites observed in this study were Heterakis gallinarum in samples from earthworms and Acuaria spiralis from woodlice. Suggestively, soil invertebrates showed a higher prevalence of endoparasites and may represent a higher potential risk in comparison to the other categories of invertebrates sampled herein. Detritivory and collected origin were also explanatory variables related to the presence of endoparasites in the current study.     

Rare earth thiocyanate complexes with tripiperidinophosphine oxide: synthesis and characterization. Crystal structure of Pr(SCN)3(tpppO)3

The synthesis and characterization of rare-earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) thiocyanate adducts with tripiperidinophosphine oxide (tpppO) with general formula (RE)(SCN)₃(tpppO)₃ are reported. Conductance measurements in acetonitrile indicate the non-electrolytic nature of the complexes. Infrared absorption spectra evidence that the SCN⁻ ion coordinates through the nitrogen atom (isothiocyanate form) and that tpppO coordinates through the phosphoryl oxygen. X-ray powder patterns suggest the existence of three different crystal forms: (1) La; (2) an isomorphous series including Ce, Nd and Pr; and (3) another isomorphous series, including Sm, Gd, Eu, Ho, Er, Tb, Lu and Y. The visible spectra of the Nd adduct and the calculated parameters β = 0.98, b^1/2 = 0.072 and δ = 1.06 indicate that the metal-ligand bonds are essentially electrostactic. The emission spectra of the Eu compound showed ⁵D₀ → ⁷F_J bands (J = 0, 1, 2), suggesting a C_3v symmetry for the coordination polyhedron. The lifetime of the ⁵D₀ state is 1.28 ms. The emission spectra of the Tb complex presented ⁵D₄ → ⁷F_J bands (J = 4, 5, 6) and the Dy complex showed the ⁴F_9/2 → ⁶H_13/2 band. The structure of the Pr complex showed that the coordination polyhedron is a trigonal antiprism, with the isothiocyanate anions in one base and three tpppO ligands in the other. Thermal analyses (TG-DTG) were carried out for the Ce, Nd and Gd adducts. Mass losses start between 250 and 334 °C. The final residues at 1300 °C are the corresponding phosphates.     

1H, 13C and 15N resonance assignment of phage T4 endoribonuclease RegB

RegB is involved in the control of the phage T4 life cycle. It inactivates the phage early mRNAs when their translation is no more required. We determined its structure and identified residues involved in substrate binding. For this, all backbone and 90% of side-chain resonance frequencies were assigned.     

Oxygen stable isotope ratios of tree-ring cellulose: the next phase of understanding

Analysis of the oxygen isotope ratio of tree-ring cellulose is a valuable tool that can be used as a paleoclimate proxy. Our ability to use this tool has gone through different phases. The first began in the 1970s with the demonstration of empirical relationships between the oxygen isotope ratio of tree-ring cellulose and climate. These empirical relationships, however, did not provide us with the confidence that they are robust through time, across taxa and across geographical locations. The second phase began with a rudimentary understanding of the physiological and biochemical mechanisms responsible for the oxygen isotope ratios of cellulose, which is necessary to increase the power of this tool. This phase culminated in a mechanistic tree-ring model integrating concepts of physiology and biochemistry in a whole-plant system. This model made several assumptions about leaf water isotopic enrichment and biochemistry which, in the nascent third phase, are now being challenged, with surprising results. These third-phase results suggest that, contrary to the model assumption, leaf temperature across a large latitudinal gradient is remarkably constant and does not follow ambient temperature. Recent findings also indicate that the biochemistry responsible for the incorporation of the cellulose oxygen isotopic signature is not as simple as has been assumed. Interestingly, the results of these challenges have strengthened the tree-ring model. There are several other assumptions that can be investigated which will improve the utility of the tree-ring model.     

An outbreak of dengue virus at Rio de Janeiro--1986

Dengue virus type 1 has been isolated in Aedes albopictus cell strain, from sera of patients living in the Nova Igua?u county, by Rio de Janeiro. The clinical picture was characterized by fever, headache, retrobulbar pain, backache, pains in the muscles and the joints and prostration. Studies in paired sera confirmed the presence of recent infection by dengue virus type 1. The outbreak reached adjacent areas, including Rio de Janeiro city (May, 1986).     

Use of dolphins and caimans as bait for Calophysus macropterus (Lichtenstein, 1819) (Siluriforme: Pimelodidae) in the Amazon

A new fishery has been developing in the Amazon that uses dolphin and caiman species as bait to catch piracatinga (Calophysus macropterus), having thus the potential to cause adverse food‐web impacts; however a lack of basic understanding of this fishery is a limitation to the necessary management action. Interviews with fishers and analyses of fishing records in Brazil were used for the study, including harvest methods, types of baits used, commercialization chains, and the rate of increase of piracatinga yields in recent years. Piracatinga fishers are subsistence fishers who harvest piracatinga as a means to alleviate economic constraints when the catch of other species is not profitable or banned due to (reproductive) closed seasons. Harvesting is done with wooden and nylon crates and cages in which whole or pieces of caimans and dolphins are placed to attract the piracatinga, entrapping them. The piracatinga are then sold to intermediate sellers for resale to a few large fish freezing and processing plants for export to Colombia. Annual piracatinga yields in the study area increased at an average rate of 446.5% per year, from 865 kg in 2003 to 23 176 kg in 2009. Because dolphins and caimans comprise various endangered species, the Brazilian government has recently implemented a ban on this fishery, which can be enforced at fish freezing and processing plants. However, there is a danger that such enforcement will lead to the development of a geographically dispersed chain of commercialization and export, such as currently exists for other species including caimans, which would be impossible to control.