Cuticular hydrocarbons from ants (Hymenoptera: Formicidae) Odontomachus bauri (Emery) from the tropical forest of Maranguape, Ceará, Brazil

Semiochemicals, 5-methyl-nonacosane, Alkanes, Chromatography.Ants are eusocial organisms with great relative abundance and species richness. Studies on these organisms are scarce, especially in the high altitude humid forest environments of the state of Ceará. In view of this condition, an evaluation of the chemical composition of cuticular hydrocarbons (CHCs) of the species Odontomachus bauri found and recorded for the first time in this study in the tropical forest of Maranguape was carried out, based on the hypothesis that different nests have different compositions of CHCs. For this purpose, collection incursions were carried out in the region to obtain individuals from three different nests. In the laboratory, the extraction of CHCs was performed by immersing the ants in hexane for 30 minutes. After removing the ants, the extracts were subjected to drying to assess the yield of the samples. Then, the extracts were subjected to a silica gel column, before performing an analysis by gas chromatography coupled with mass spectrometry. The chromatograms obtained were analyzed and demonstrated a great similarity, showing long-chain saturated hydrocarbons, mainly represented by alkanes and methyl-alkanes. 5-Methyl-nonacosane was the component with the highest relative abundance. Statistical analysis of similarity and correlation between samples was performed using non-parametric tests. These analyzes provided sufficient statistical evidence to confirm the existence of a strong positive correlation between the samples and also a significant difference in the composition of HCCs in two of the three paired analyzes performed, thus confirming the study hypothesis.

Effects of Thymol and Thymol α-D-Glucopyranoside on Intestinal Function and Microbiota of Weaned Pigs

The present study evaluated gluco-conjugation as a measure to delay thymol absorption and enhance its antimicrobial activity in the gut of weaned piglets. The three dietary treatments consisted of a basal diet without additives (TCON), supplemented with thymol at 3.7 mmol/kg dry matter (TTHY), or with an equimolar amount of thymol α-D-glucopyranoside (TTαG). Each dietary treatment was replicated in 6 pens with 2 piglets per pen (n = 12 for analytical parameters) and was supplemented for 14 days. The total (free plus gluco-conjugated) thymol concentrations in the stomach contents were 14% lower in TTαG as compared to TTHY piglets. Neither of the additives could be detected further down the gut. E.coli counts in the proximal small intestine were significantly lower in TTHY than in TTαG pigs (3.35 vs. 4.29 log10 CFU/g); however, other bacterial counts and their metabolites were unaffected by treatment. A metagenomic bacterial analysis revealed a great relative abundance of Lactobacillus spp. in the distal small intestine (range 88.4–99.9%), irrespective of treatment. The intestinal barrier function was improved by TTHY, but not TTαG, compared to TCON. In conclusion, gluco-conjugation did not result in higher thymol concentrations in the gut, but conversely, it seemed to diminish the biological effects of thymol in vivo.

Quinones and non-quinones from the defensive secretion of Unciger transsilvanicus (Verhoeff, 1899) (Diplopoda, Julida, Julidae), from Serbia

A complex mixture of compounds was identified from the secretion of specimens of Unciger transsilvanicus. Phenol and p-cresol were detected for the first time in the family Julidae, and for the second time in the order Julida. Thirteen quinones were identified, with a great relative abundance of toloquinone and 2-methoxy-3-methyl-1,4-benzoquinone. Hydroquinone was detected for the first time in the order Julida. Besides these compounds, isopentyl hexacosatetraenoate and isopentyl esters of saturated and unsaturated fatty acids with chain lengths from C14 to C20were identified. The most abundant non-quinone compound was isopentyl eicosenoate. The relative abundance of quinone and non-quinone in the defensive fluid of U. transsilvanicus was 77% and 23%, respectively. The phylogenetic importance of the registered compounds is briefly discussed.