A computational investigation of sulfur-containing heterocyclic components from the anal sac secretions of Mustela species.

A computational investigation of the sulfur-containing heterocyclic components (substituted thietanes and 1,2-dithiolanes) of Mustela anal sac secretions has been carried out. A cluster analysis of the chemical compositions of Mustela anal sac volatiles reveals little similarity with established phylogenetic relationships between members of the genus. Ab initio calculations [MP2/6-311++G(2df,2p)//B3LYP/6-311++G**] show the lowest-energy C5H10S isomeric thietane to be 2,2-dimethylthietane, which is also the most abundant of the Mustela thietanes. Similarly, 3,3-dimethyl-1,2-dithiolane is the lowest-energy C5H10S2 compound. 2-n-Propylthietane is the highest-energy C6H12S compound, but the most abundant Mustela C6H12S compound produced, whereas cis-2-ethyl-4-methylthietane, the lowest-energy C6H12S thietane, has never been observed in Mustela anal sac secretions. A molecular docking analysis of the Mustela sulfur-containing heterocycles into both porcine and bovine odorant binding proteins reveals the interactions of the docked ligands with the proteins to be largely hydrophobic, and have binding energies generally lower than typical odorant molecules such as linalool or eugenol.

Differences among antimicrobial properties of carrion beetle secretions reflect phylogeny and ecology.

Carrion beetles (Coleoptera: Silphidae) consist of two subfamilies in North America. Members of the Silphinae arrive at carcasses during the mid-stage of decay and their larvae feed on developing maggots, while members of the Nicrophorinae bury and tend carcasses upon which their developing larvae feed. The Nicrophorinae maintain the condition of the carcass by applying oral and anal secretions that reduce carcass decay apparently through bacterial inhibition, although quantification has not been made. We hypothesized that enzymes in the oral and anal secretions of the subfamily Nicrophorinae would inhibit bacterial growth, while secretions from the subfamily Silphinae would not. The secretions were assayed for inhibitory effects with a Microtox Analyzer that monitors the decrease in bioluminescence from the bacterium Vibrio fischerii. We found a significant difference of bioluminescence in the control compared to secretions of 8 out of 10 tested Nicrophorinae (with oral secretions being most active), while only anal secretions from Necrodes surinimensis of the Siphinae significantly reduced bacterial survival. These data follow the known phylogenic relationship in which Necrodes is the closest genus to the Nicrophorinae. The two species of Nicrophorinae, which did not show significant reductions in bacterial growth, differ ecologically from the others. Thus, the presence of antimicrobial compounds in most Nicrophorinae secretions, but not in most other Silphinae, represents an adaptation to preserve the buried carcass.

Volatile components in defensive spray of the hooded skunk, Mephitis macroura.

GC-MS analysis of the anal sac secretion from the hooded skunk, Mephitis macroura, showed the following seven major components comprised 99% of the volatiles in this secretion: (E)-2-butene-1-thiol, 3-methyl-1-butanethiol, S-(E)-2-butenyl thioacetate, S-3-methylbutenyl thioacetate, 2-phenylethanethiol, 2-methylquinoline, and 2-quinolinemethanethiol. Minor volatile components identified in this secretion are phenylmethanethiol, S-phenylmethyl thioacetate. S-2-phenylethyl thioacetate, bis[(E)-2-butenyl] disulfide, (E)-2-butenyl 3-methylbutyl disulfide, bis(3-methylbutyl) disulfide, and S-2-quinolinemethyl thioacetate. This secretion is similar to that of the striped skunk, Mephitis mephitis, differing only in that it contains four compounds not reported from the striped skunk: phenylmethanethiol, S-phenylmethyl thioacetate, 2-phenylethanethiol, and S-2-phenylethyl thioacetate.

Cytological and lectin histochemical characterization of secretion production and secretion composition in the tubular glands of the canine anal sacs.

The study reports on secretion production and composition in the tubular glands of the canine anal sacs. For this purpose, light and electron microscopical (TEM, SEM) as well as several histochemical methods for the demonstration of lysosomal acidity, lipofuscin, and complex carbohydrates were used. The glandular tubules exhibited a pseudostratified epithelium with secretory cells of a different shape as related to secretion production activity, and regionally varying amounts of basal cells. Flat, cuboidal or columnar cells with or without apocrine-like protrusions were assembled in one glandular endpiece, although grouping of these cell types often occurred. Active secretory cells were columnar with many cytoplasmic vesicles and a typically merocrine and/or micro-apocrine exocytosis of vesicle contents. Additionally, many lysosomes of different sizes could be found, whereby in aged cells giant secondary lysosomes (autophagolysosomes, about 7 microm in diameter) occupied the major cell part. These giant lysosomes were shed by an apocrine-like process forming a final bottleneck stage of the upper cell part, and consisted of ceroid-type lipofuscin. The general carbohydrate histochemical and the lectin histochemical methods revealed that the secretion produced was composed of strongly concentrated neutral glycoproteins with the following saccharide residues: alpha-D-mannose, beta-D-galactose, beta-N-acetyl-D-glucosamine, alpha-L-fucose and N-acetyl-neuraminic acid (sialic acid); the luminal secretion contained only beta-D-galactose and, especially, N-acetyl-neuraminic acid. This luminal secretion showed a spatially orientated maturation beginning in terminal tubular regions and finishing near the excretory duct, independent of the different secretory cell types. The results obtained demonstrated highly active secretion production, with a regional variation in the glandular tubule, and at least three different modes of secretion by the secretory cells, whereby the shedding of giant lipofuscin granules seems to be very specific. The high amounts of sialic acids in the glycoproteins found may influence the rheological properties of the secretion by their water-binding capacities.