Genetic differentiation of Elysia timida (Risso, 1818) populations in the Southwest Mediterranean and Mar Menor coastal lagoon

Genetic variation at 10 enzyme loci was analysed in Elysia timida sacoglossan mollusc samples, originating from both coastal lagoon and marine sites. The observed heterozygosity ranged from 0.390 (Los Urrutias) to 0.277 (Tabarca). Marine and coastal lagoon populations were characterised by exclusive alleles.     

Isolation and PCR detection of <Emphasis Type="Italic">Enterobacter sakazakii</Emphasis> in South African food products,specifically infant formula milks

Enterobacter sakazakii has recently been identified as an opportunistic pathogen. The current culture-dependent detection methods for these bacteria are time-consuming and in this study a PCR method for the detection of E. sakazakii in South African food products, including an internal amplification control (IAC) was developed. DNA was isolated and amplified from the products and they were plated on selective growth media after pre-enrichment and enrichment in Enterobacteriaceae enrichment broth. Four of the 22 products tested positive for the presence of E. sakazakii, confirmed by PCR detection and growth on selective media. The PCR method proved effective in detecting E. sakazakii in South African products after three days and could serve as an alternative for traditional microbiological techniques.     

Application of polyethyleneimine cellulose for the class separation of steroidal carboxylic acids from neutral steroids and pigments in urine

Metabolites of corticosteroids that contain the 21-oic acid moiety are found in human urine. The acids from neutral steroids and urinary pigments have been separated by passing the mixture through a column of polyethyleneimine cellulose. The acids adhering to the column are quantitatively eluted with dilute formic acid. The purified preparation is suitable for derivatization and chromatographic analysis.     

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications.     

Rock selection for nesting inProformica longiseta Collingwood, 1978 (Hymenoptera,Formicidae) in a Mediterranean high mountain

Proformica longiseta, an ant species endemic to certain high mountains, has been studied with regard to its tendency to nest underneath rocks. This behaviour led us to investigate whether a particular type of rock is selected, and, if so, the advantages to this species of the selection. This study was located at 2400 m above sea-level in the Sierra Nevada mountains (Granada, Spain). To determine the range of rock sizes available, in eight control plots the thicknesses were recorded and also the maximum and minimum diameters of all rocks with surface area of more than 6 cm². A total of 1724 rocks were recorded, noting among the rock types available those that were used for nesting. Also as a preliminary estimate of the thermal characteristics of the rocks, we recorded the temperatures of the air, soil surface, soil under a rock covering an ant nest, and soil at 30 cm depth. The results indicate thatP. longiseta selects flat rocks with a surface area/thickness ratio of 2–5, the thickness being not less than 1.5 cm, the surface area being 50–250 cm² and volume less than 1000 cm³. This type of rock offers the nests two beneficial but apparently contradictory effects: (1) protection against high temperatures on hot days, and (2) warmth on colder days by absorbing the diffusing solar heat more effectively than the air or soil around the nest.     

Anti-inflammatory effect of l-cysteine (a semi-essential amino acid) on 5-FU-induced oral mucositis in hamsters

Oral mucositis is an inflammation of the oral mucosa mainly resulting from the cytotoxic effect of 5-fluorouracil (5-FU). The literature shows anti-inflammatory action of l-cysteine (l-cys) involving hydrogen sulfide (H₂S). In view of these properties, we investigate the effect of l-cys in oral mucositis induced by 5-FU in hamsters. The animals were divided into the following groups: saline 0.9%, mechanical trauma, 5-FU 60–40 mg/kg, l-cys 10/40 mg and NaHS 27 µg/kg. 5-FU was administered on days 1st to 2nd; 4th day excoriations were made on the mucosa; 5th–6th received l-cys and NaHS. For data analysis, histological analyses, mast cell count, inflammatory and antioxidants markers, and immunohistochemistry (cyclooxygenase-2(COX-2)/inducible nitric oxide synthase (iNOs)/H₂S) were performed. Results showed that l-cys decreased levels of inflammatory markers, mast cells, levels of COX-2, iNOS and increased levels of antioxidants markers and H₂S when compared to the group 5-FU (p < 0.005). It is suggested that l-cys increases the H₂S production with anti-inflammatory action in the 5-FU lesion.

     

The hypotensive drug 2-hydroxyoleic acid modifies the structural properties of model membranes

We studied the interactions of the hypotensive drug, 2-hydroxyoleic acid (2OHOA), with model membranes using the techniques of DSC, ³¹P NMR and X-ray diffraction. We demonstrate that 2OHOA alters the thermotropic behaviour of 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE), thereby promoting the formation of hexagonal phases (H_II), despite stabilizing the lamellar phase (L_α). The lattice parameters of lamellar and non-lamellar structures were not altered by the presence of 2OHOA. The molecular bases underlying the alterations in membrane structure provoked by 2OHOA were analysed by comparing the effects produced by 2OHOA with the closely related fatty acids (FAs), oleic acid (OA) and elaidic acid (EA). The capacity of C-18 FAs to induce H_II-phase formation followed the order OA>2OHOA>EA. Furthermore, while 2OHOA stabilized the L_α phase, OA destabilized it. The net negative charge of 2OHOA at physiological pH (～7.4) influenced its effect on membrane structure. By analysing the molecular architecture of 2OHOA in DEPE monolayers, interactions between the carboxylate groups of 2OHOA and the amine groups of DEPE were observed, as well as between the 2-hydroxyl group of the FA and the carbonyl oxygen of the phospholipid acyl chain. These structural characteristics provoked an increase in the P-to-N and P-to-P distances of neighbouring phospholipid headgroups in the presence of 2OHOA, with respect to those observed with OA and EA. The higher headgroup area at the lipid–water interface in presence of 2OHOA could account for the differential effect of this drug on the phase behaviour of DEPE membranes.