Biological activities of Annona montana Macfad extracts

Annona montana Macfad is a fruit species of the Annonaceae family. In this study, the phytochemical potential of A. montana seeds was investigated. Ethanol and hexane extracts from seeds were evaluated for cytotoxicity and insecticidal activity, phenolic content, and antioxidant capacity. The latter being related to free radical scavenging activity assay (DPPH) and ferric reducing power (FRAP). Exposing Artemia salina to both seed extract types reveled their high toxicity with a median lethal concentration (LC50) of < 10 μg mL-1. Further A. montana seed insecticidal activity was evaluated against Thrips tabaci L., revealing that the most promising treatments were observed for a concentration of 100 mg L-1 in both extracts. The ethanol extract resulted in a mortality of 67.5 % and the hexane extract in a 53.3 % mortality. The ethanolic extract of A. montana seeds showed the highest total phenolic content: 297.38 mg GAE/100 g of dried extract and 192.66 mg TE/100 g, and 385.46 mg TE/100 g for DPPH and FRAP, respectively. The chemical characterization of both extracts by high performance liquid chromatography (HPLC) revealed the presence of acetogenins. The results obtained idicate that the A. montana extracts are a promising source of compounds with insecticidal activity.

Morphological characterization of dermal denticles of the Broadnose Sevengill Shark Notorynchus cepedianus (Elasmobranchii: Hexanchidae)

Shark skin is covered by small structures called dermal denticles whose functions are diverse, such as protection, bioluminescence, hydrodynamics, among other functions. These structures have a great variety of shapes and sizes, which can be a useful approach for specimen identification as diagnostic characters between species. The present study aims to describe the dermal denticles morphology of the broadnose seven-gill shark Notorynchus cepedianus, evaluating differences among life-stage (neonate, juvenile and adult), sex and body region (dorsal and ventral). For achieving it, 39 specimens were collected at six landing points along the Peruvian coast. The dermal denticles from two body regions(dorsal and ventral) were photographed, measured (length, width, angle and density), and described using a stereoscope. Dermal denticles measures showed significant morphological differences between body regions as well as stages of development, but not between sexes. The differences are: (1) Crown shape: as the individual grows, it can be seen that the cross shape is losing, (2) Crown cusps: cusps length varied according to the stage of each individual, it was also observed that the lateral cusps are larger in dorsal than ventral region, and (3) Union peduncle - crown: adult specimens and both body regions, the observed union was very dimly and it did not have a defined shape. On the whole, these reported variations in measured traits could be useful as diagnostic characters to identify the stage of development at which the landed and marketed specimens are found.

Zooplankton distribution in Mesophotic Corals at Bajo Frijol seamount, Colombian Caribbean

Mesophotic coral ecosystems shelter unique communities, but have not been studied enough due to the high cost for the available technologies. The zooplankton have become the primary food resource of the polyps at these environments, due to the low photosynthesis rate of its zooxanthellae, . Therefore, the purpose of this work was to study the zooplankton community associated to the MCEs in Bajo Frijol, in the Corales de Profundidad National Natural Park, and compare its composition with the zooplankton community from shallower parts of the water column. Three samples were taken, filtering 24 L of seawater (45 µm mesh size) at each station with a device designed to collect zooplankton right on top of the reef substrate. The taxonomic composition, density and relative abundance were obtained. A resemblance analysis was performed, complemented with a cluster, an MDS and a modified Kandoorp test. The analysis showed clear differences between the water column samples from those taken close to the reef. It also showed the separation of the community at the seamount into two large groups: north and center-south, both with exclusive species.

Molecular techniques for the assessment of Cr (VI) reduction by Bacillus thuringiensis

Effluent pollution with Cr (VI) is a worldwide environmental problem. In the Pasto River (southeastern, Colombia), previous studies reported contamination with this metal at points near tanneries. To establish the role of Bacillus thuringiensis in Cr (VI) reduction in water from Pasto River, experiments were carried out with untreated Pasto River water (treatment 1), sterile Pasto River water inoculated with B. thuringiensis (treatment 2), and unsterilized Pasto River water inoculated with B. thuringiensis (treatment 3). All experiments were conducted in bioreactors with a controlled temperature of 20 °C and constant agitation for 156 h. Samples of 20 mL were taken every 12 h from each treatment to track Cr (VI) reduction levels and to confirm microorganism identity via molecular methods involving denaturing gradient gel electrophoresis (DGGE), restriction enzyme digestion profiles (RFLP), and bioinformatic analysis. Cr (VI) reduction was higher in treatment 3 (99:42 %) as opposed to treatment 2 (76:12 %) and treatment 1 (74:46 %). The molecular identity of B. thuringiensis was determined via sequencing of the 16SrRNA gene, and RFLP assessments in all three treatments revealed B. thuringiensis profiles. Since B. thuringiensis was present in all three treatments trough time, Cr (VI) reduction can be attributed to this bacterium.

Coupling effects of structure, oxygen availability and temperature on microbial growth in a pastry filling

The structure of real food is a key factor to be considered in order to control microbial growth. A pastry filling has been employed as model food to study the growth of Staphylococcus under different conditions. Additionally, the structure of the food system has been characterised by means of rheological measurements. Frequency sweeps showed that, in all cases, the elastic component determines the rheological behaviour of model pastry filling (G' > G''). Values obtained for the coordination number (z) and the proportional coefficient (A) indicated that the model food exhibits more aggregate structures and stronger links at lower temperatures. According to the maximum specific growth rates, the Staphylococcus growth in the model pastry filling was clearly conditioned by oxygen diffusion, which is limited by the food matrix, and also by the incubation temperature. In addition, the analysis of Staphylococcus growth at different temperatures suggested the influence of the pastry filling structure on microorganism behaviour.

Potential phenotypic plasticity within Simulium nigrimanum Macquart, 1838 (Diptera: Simuliidae) larvae

Black fly larvae (Diptera: Simuliidae) are suspension filter-feeders which strongly depend on water velocity for proper feeding. Black fly species feature different microhabitat preferences. Studies of Holarctic black fly larvae revealed their phenotypic plasticity in response to water current velocity variation, but such studies have been rarely undertaken with Neotropical black flies. The current work presents results on the phenotypic plasticity of the black fly species Simulium nigrimanum Macquart. Twelve last instar larvae, sampled from the Brazilian Cerrado, were photographed under a stereoscopic microscope and measured using the CMEIAS Image tool software. Linear regressions with water velocity as the independent variable were performed, indicating that while body size and anal disk diameter correlated positively with water velocity, labral fan length correlated negatively. The observed relationships between water velocity and labral fan length and anal disk diameter were consistent with the literature, while the pattern of body size variation partially corroborated previous studies. The present work results suggest that potential phenotypic plasticity can be observed in black fly larvae within one population distributed in different microhabitats of the same stream section, as opposed toprevious reports implying that such variation is only found among population from different streams.

Synthesis and characterization of four N-acylhydrazones as potential O,N,O donors for Cu2+: An experimental and theoretical study

N-acylhydrazones 2-(4-chlorophenyl)-N0 -(2-hydroxybenzylidene)acetohydrazide, N0 -(2-hydroxybenzylidene)-2-(4-methoxyphenyl)acetohydrazide, 2-(4-chlorophenyl)-N0 -(2,4-dihydroxybenzylidene)-acetohydrazide, and N0 -(2,4-dihydroxybenzylidene)-2-(4-methoxyphenyl)acetohydrazide were successfully synthesized by a multistep procedure. The obtained organic molecules were characterized by spectroscopic techniques (FT-IR, 1D and 2D NMR, UV-Vis) and mass spectrometry. The structure of 2-(4-chlorophenyl)-N0 -(2-hydroxybenzylidene)acetohydrazide was also confirmed by X-ray diffraction. Ab initio computational simulations of the ligand spectra were in good agreement with experimental data and validated the hypothesis about the existence of a conformational mixture of each ligand in solution. Finally, the complexation potential of the synthesized ligands to Cu2+ was assessed by continuous variation experiments and FT-IR spectroscopy.

An investigation on using measurement uncertainty as decision rule for statement of conformity

This research article refers to the application of the evaluated measurement uncertainty for deciding the statement of conformity. It is a proposal to rethink about the classification of measuring devices, taking into account the calculations of uncertainty as a decision rule. It is also a base for complete compatibility and harmonization between ISO 17025:2017 and the other standards. To verify this proposal a case study on compression testing machine classification is used. This proposal aims to review classification criteria for these machines. Since the uncertainty value is equivalent to all parameters that may affect the performance of these machines, it is logical and accurate to use it as the basis for the classification. This approach may be employed for the upcoming version of ISO 7500 standard to use the uncertainty value as a base for machine classification.

Extension of Dasgupta’s Technique for Higher Degree Approximation

In the present paper, rational wedge functions for degree two approximation have been computed over a pentagonal discretization of the domain, by using an analytic approach which is an extension of Dasgupta’s approach for linear approximation. This technique allows to avoid the computation of the exterior intersection points of the elements, which was a key component of the technique initiated by Wachspress. The necessary condition for the existence of the denominator function was established by Wachspress whereas our assertion, induced by the technique of Dasgupta, assures the sufficiency of the existence. Considering the adjoint (denominator) functions for linear approximation obtained by Dasgupta, invariance of the adjoint for degree two approximation is established. In other words, the method proposed by Dasgupta for the construction ofWachspress coordinates for linear approximation is extended to obtain the coordinates for quadratic approximation. The assertions have been supported by considering some illustrative examples.

Assessment of lignocellulosic residues from Northern Patagonian Andes (Argentina) for cultivation of Pleurotus ostreatus

This work evaluated mycelial growth rate (Kr) and fruiting of two Pleurotus ostreatus commercial strains (A01, 129) on formulations composed of lignocellulosic residues from farming and agroindustry of Northern Patagonian Andes, and of woody materials from invasive plants. Rosehip fluffs (RF), rosehip woodchips (RWC), southern beech wood shavings (SBWS), wheat straw (WS), and willow woodchips (WWC) were used as base substrates, and brewing bagasse (BB) as an alternative supplement to wheat bran (WB). Kr was higher in WS-WB and WS-BB for both strains. Experiments in fruiting chambers showed biological efficiencies (BEs) above 40% in WS-BB (both strains) and WS-WB (strain 129). Formulations using RWC or WWC gave BEs under 40%, while those composed of SBWS or RF showed lower Kr and contamination by moulds. Medium-scale fruiting experiments using strain A01 showed the highest BEs in WS-BB and RWC-WB. These results suggest that WS is the best substrate for Pleurotus ostreatus culture, although scarce in Northern Patagonian Andes. Nevertheless, WWC and RWC are suggested as alternative substrates, while BB is cheap and abundant, suitable as an alternative supplement to WB.