Time-place learning in individually reared angelfish, but not in pearl cichlid

Time-place learning based on food association was investigated in the cichlids angelfish (Pterophyllum scalare) and pearl cichlid (Geophagus brasiliensis) reared in isolation, therefore eliminating social influence on foraging. During a 30-day period, food was placed in one side of the aquarium (containing three compartments) in the morning and in the opposite side in the afternoon. Learning was inferred by the number of correct side choices of all fish in each day of test (15th and 30th). During the test day fish were not fed. The angelfish learned to switch sides at the correct day period in order to get food, suggesting this species has time-place learning ability when individually reared. On the other hand, the same was not observed for pearl cichlid.     

Hypotensive activity of terpenes found in essential oils

The cardiovascular activity of essential oils has been reported. Some studies showed that the main chemical components of these oils contribute to their pharmacological activity. Therefore, the cardiovascular activity of four monoterpenes and one sesquiterpene was evaluated in the present work. In non-anaesthetized normotensive rats, (+)-alpha-pinene, (-)-beta-pinene, (+/-)-citronellol and (+/-)-linalool (1, 5, 10, and 20 mg/kg, i.v.) induced hypotension [maximal effect: (-35 +/- 3)%, (-46 +/- 4)%, (-48 +/- 2)% and (-40 +/- 2)%, respectively; n=6] and tachycardia [maximal effect: (13 +/- 4)%, (16 +/- 7)%, (21 +/- 1)% and (19 +/- 3)%, respectively; n=6] while (-)-a-bisabolol (1, 5, 10, and 20 mg/kg, i.v.) induced hypotension [maximal effect: (-47 +/- 8)%, n=6] and bradycardia [maximal effect: (-57 +/- 3)%]. In conclusion, these results demonstrated that all terpenes tested had hypotensive activity in rats and that the pharmacological effect of the terpene alcohols was more effective than that of the terpene hydrocarbons.     

Search for a platelet-activating factor receptor in the Trypanosoma cruzi proteome: a potential target for Chagas disease chemotherapy

Chagas disease (CD) causes the highest burden of parasitic diseases in the Western Hemisphere and is therefore a priority for drug research and development. Platelet-activating factor (PAF) causes the CD parasite Trypanosoma cruzi to differentiate, which suggests that the parasite may express PAF receptors. Here, we explored the T. cruzi proteome for PAF receptor-like proteins. From a total of 23,000 protein sequences, we identified 29 hypothetical proteins that are predicted to have seven transmembrane domains (TMDs), which is the main characteristic of the G protein-coupled receptors (GPCRs), including the PAF receptor. The TMDs of these sequences were independently aligned with domains from 25 animal PAF receptors and the sequences were analysed for conserved residues. The conservation score mean values for the TMDs of the hypothetical proteins ranged from 31.7-44.1%, which suggests that if the putative T. cruzi PAF receptor is among the sequences identified, the TMDs are not highly conserved. These results suggest that T. cruzi contains several GPCR-like proteins and that one of these GPCRs may be a PAF receptor. Future studies may further validate the PAF receptor as a target for CD chemotherapy.     

Synthesis, characterization and coordination chemistry of dibenzofuran derivatives of 1,4,7,10-tetraazacyclododecane

A 1,4-disubstituted dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane (cyclen), L1, has been prepared by the direct reaction of cyclen and chloroacetyldibenzofuran and the mono-substituted derivative, L2, by reaction of chloroacetyldibenzofuran and 1,4,7-tris(t-butoxycarbonyl)-1,4,7,10-tetraazacyclododecane followed by deprotection with trifluoroacetic acid. The ligands were characterized by ¹H and ¹³C NMR spectroscopy, IR spectroscopy and mass spectrometry. The reaction of the 1,4-disubstituted dibenzofuran cyclen, L1, with Cu(ClO₄)₂·6H₂O in methanol yielded crystals of [CuL1](ClO₄)₂·MeOH·1/2H₂O that were suitable for single crystal structural analysis. The X-ray structure confirmed that the 1,4-disubstituted dibenzofuran cyclen had been formed. The copper(II) coordination sphere in the complex cation, [CuL1]²⁺, is occupied by four nitrogen atoms from the macrocycle and an amide oxygen donor from one dibenzofuran pendant group. As is typical for copper(II)-cyclen complexes, the Cu(II) centre sits above the plane of the macrocycle nitrogen towards the oxygen donor, in this case by 0.5 Å. Fluorescence emission studies indicate that coordination of the macrocycle to either copper(II) or zinc(II) results in a decrease in emission with respect to the emission of the pure ligand.     

Inhibition by a nonmetabolized analogue of L-leucine of protein biosynthesis in tumoral pancreatic islet cells

The effect of L-leucine, its deaminated metabolite 2-ketoisocaproate and its nonmetabolized analogue b(+/-)2-aminobicyclo[2,2,1]-heptane-2-carboxylic acid (BCH) upon protein labelling was examined in tumoral islet cells (RINm5F line) exposed to L-[4-3H]phenylalanine or L-[3-3H]serine. The interpretation of the results, in terms of changes in biosynthetic activity, was obscured by a possible interference of the tested nutrients with the uptake and further metabolism of the tracer tritiated amino acids. Nevertheless, when the cells were preincubated with the nutrient secretagogues and then incubated in the sole presence of L-[3-3H]serine, BCH, but not L-leucine or 2-ketoisocaproate, still inhibited protein labelling, this coinciding with a decrease in the ratio between TCA-precipitable and total radioactivity in the RINm5F cells. The inhibitory action of BCH was antagonized, to a limited extent, by D-glucose. It is proposed that BCH could be used as a tool to interfere with the function and growth of insulinoma cells.     

Immunopositivity for Siglec-15 in gastric cancer and its association with clinical and pathological parameters

The sialic acid-binding immunoglobulin-type lectin Siglec-15 is a promising target for cancer immunotherapy in several tumor types. The present study aimed to investigate Siglec-15 expression in gastric cancer (GC) patient tissues and to evaluate its clinical value. Siglec-15 expression was evaluated by immunohistochemistry in 71 patients. Siglec-15 staining was observed in tumor cells of 53 (74.64%) patients, with significant association with histologic classification and angiolymphatic invasion (p<0.05). Immunohistochemistry analysis also detected Siglec-15 in tumor-associated stroma cells (macrophages/myeloid cells). There was no significant association with outcome parameters. Siglec-15 expression in well differentiated histological GC tissues and in the tumor microenvironment are potential targets to be further investigated as a novel prognostic factor for GC.Key words: Siglec, sialic acid, immunohistochemistry, clinical-pathological analyses     

Dissolving microneedles containing aminolevulinic acid improves protoporphyrin IX distribution

One important limitation of topical photodynamic therapy (PDT) is the limited tissue penetration of precursors. Microneedles (MNs) are minimally invasive devices used to promote intradermal drug delivery. Dissolving MNs contain drug-associated to polymer blends, dissolving after insertion into skin, allowing drug release. This study comprises development and characterization of a pyramidal model of dissolving MNs (500 μm) prepared with 5% wt/wt aminolevulinic acid and 20% wt/wt Gantrez AN-139 in aqueous blend. Protoporphyrin IX formation and distribution were evaluated in tumor mice model by using fluorescence widefield imaging, spectroscopy, and confocal microscopy. MNs demonstrated excellent mechanical resistance penetrating about 250 μm with minor size alteration in vitro, and fluorescence intensity was 5-times higher at 0.5 mm on average compared to cream in vivo (being 10 ± 5 a.u. for MNs and 2.4 ± 0.8 a.u. for cream). Dissolving MNs have overcome topical cream application, being extremely promising especially for thicker skin lesions treatment using PDT.     

Assessing invertebrate herbivory in human‐modified tropical forest canopies

1. Studies on the effects of human‐driven forest disturbance usually focus on either biodiversity or carbon dynamics but much less is known about ecosystem processes that span different trophic levels. Herbivory is a fundamental ecological process for ecosystem functioning, but it remains poorly quantified in human‐modified tropical rainforests.
2. Here, we present the results of the largest study to date on the impacts of human disturbances on herbivory. We quantified the incidence (percentage of leaves affected) and severity (the percentage of leaf area lost) of canopy insect herbivory caused by chewers, miners, and gall makers in leaves from 1,076 trees distributed across 20 undisturbed and human‐modified forest plots in the Amazon.
3. We found that chewers dominated herbivory incidence, yet were not a good predictor of the other forms of herbivory at either the stem or plot level. Chewing severity was higher in both logged and logged‐and‐burned primary forests when compared to undisturbed forests. We found no difference in herbivory severity between undisturbed primary forests and secondary forests. Despite evidence at the stem level, neither plot‐level incidence nor severity of the three forms of herbivory responded to disturbance.
4. Synthesis. Our large‐scale study of canopy herbivory confirms that chewers dominate the herbivory signal in tropical forests, but that their influence on leaf area lost cannot predict the incidence or severity of other forms. We found only limited evidence suggesting that human disturbance affects the severity of leaf herbivory, with higher values in logged and logged‐and‐burned forests than undisturbed and secondary forests. Additionally, we found no effect of human disturbance on the incidence of leaf herbivory.

     

PMA-sensitive protein kinase C is not necessary in TRH-stimulated prolactin release from female rat primary pituitary cells.

In GH3 cells and other clonal rat pituitary tumor cells, TRH has been shown to mediate its effects on prolactin release via a rise of cytosolic Ca2+ and activation of protein kinase C. In this study, we examined the role of protein kinase C in TRH-stimulated prolactin release from female rat primary pituitary cell culture. Both TRH and PMA stimulated prolactin release in a dose-dependent manner. When present together at maximal concentrations, TRH and PMA produced an effect which was slightly less than additive. Pretreatment of rat pituitary cells with 10(-6) M PMA for 24 hrs completely down-regulated protein kinase C, since such PMA-pretreated cells did not release prolactin in response to a second dose of PMA. Interestingly, protein kinase C down-regulation had no effect on TRH-induced prolactin release from rat pituitary cells. In contrast, PMA-pretreated GH3 cells did not respond to a subsequent stimulation by either PMA or TRH. Pretreatment of rat pituitary cells with TRH (10(-7) M, 24 hrs) inhibited the subsequent response to TRH, but not PMA. Forskolin, an adenylate cyclase activator, stimulated prolactin release by itself and in a synergistic manner when incubated together with TRH or PMA. The synergistic effects of forskolin on prolactin release was greater in the presence of PMA than TRH. Down-regulation of protein kinase C by PMA pretreatment abolished the synergistic effect produced by PMA and forskolin but had no effect on those generated by TRH and forskolin. sn-1,2-Dioctanylglycerol (DOG) pretreatment attenuated the subsequent response to DOG and PMA but not TRH. The effect of TRH, but not PMA, on prolactin release required the presence of extracellular Ca2+. In conclusion, the mechanism by which TRH causes prolactin release from rat primary pituitary cells is different from that of GH3 cells; the former is a protein kinase C-independent process whereas the latter is at least partially dependent upon the activation of protein kinase C.     

Linking disturbances in neotropical landscapes with ecosystem functional traits: A preliminary assessment using epigaeic and leaf-litter ant communities

1. Environmental stressors and changes in land use have led to rapid and dramatic species losses and a reduction in associated ecosystem services.
2. Functional diversity has increasingly been suggested as an alternative for evaluating anthropogenic disturbances and restoration programs because it reflects different aspects of the relationship between biological diversity, ecosystem functioning and environmental constraints.
3. Ants are important components of terrestrial food webs and a key group associated with diverse interactions and ecosystem processes.
4. Additionally, their sensitiveness and rapid response to environmental changes pave the way for their use as informative metrics for monitoring several processes that threaten biodiversity and ecosystem services.
5. Consequently, ants' functional diversity might be considered leading edge indicators to assess ecosystem changes to ongoing anthropogenic disturbances.
6. The purpose of this study was to gauge the usefulness of epigaeic and leaf-litter ants' functional responses towards measuring ecosystem degradation (and/or restoration) in the Brazilian Amazon.
7. Our results demonstrate that functional traits exhibited sensitivity to ongoing changes, as well as different responses to specific environmental disturbances.
8. Communities supporting ants with specialised functional traits associated with pristine ecosystems suffered high species loss and were correlated with specific anthropogenic stressors.
9. The results obtained pinpoint the importance of pristine ecosystems for conserving unique functional attributes and biodiversity in neotropical forest landscapes.
10. We highlight the significance of further studies in this scope to guide environmental managers and practitioners in applying the best policies for integrated neotropical landscapes conservation, considering the competing interests of farmers, foresters and conservationists, but also the unpredictable effects of local and regional environmental changes.