Characterization of amniotic fluid of Dohne Merino ewes (Ovis aries) and its possible role in neonatal recognition.

Amniotic fluid (AF) was investigated as a possible source of the neonatal recognition cue that plays a crucial role in ewe-lamb bonding in sheep. A total of 70 of the 133 volatile organic compounds (VOCs), previously identified in the cranial wool of neonatal Dohne Merino lambs, was also identified in AF collected individually from neonatal twins. As in the case of the wool of neonatal lambs, the VOC profiles (GC-MS) of the AF of twins were remarkably similar. However, the VOC profiles of the AF differed from that of the wool VOCs of the same lambs. The VOCs that best represent the total variance in the AF and wool of neonatal lambs were not identified as ligands of the AF proteins. These observations suggest that it is unlikely that the neonatal recognition cue of sheep could be a maternal label derived from the AF in which a lamb is born, and that the neonatal recognition cue is probably produced by the lamb. Taking cognizance of the temporal changes that take place in the quantitative composition of the cranial wool VOCs, we hypothesize that components of the neonatal recognition cue are already produced by the lamb well before its birth and that the quantitative composition in which these volatiles are released into the AF does not correspond to the composition of the recognition cue of the lamb at its birth. When grooming the newborn lamb, its mother removes AF containing incorrect chemical information from her lamb's body and this affords her enough time to learn its personal recognition cue.

Temporal changes in the neonatal recognition cue of Dohne Merino lambs (Ovis aries).

The strong bond that is formed between ewe and lamb after parturition is important for lamb survival. Evidence exists that the ewe mainly employs olfactory recognition cues to distinguish her lamb from other lambs in the flock. We have found that volatile organic compounds in the wool of Merino lambs that presumably constitute the neonatal recognition cue in sheep undergo temporal changes, at least during the first 100 days of their lives. To compensate for changes in the composition of the recognition cue, ewes are compelled to sample the changing effluvia of lambs to refresh their memories of their lambs' odor in order to preserve the exclusive olfactory attachment to their lambs. These changes could be the reason for the well-known regular sniffing of ewes at their lambs. Parallel changes in the effluvia of twin lambs ensure the retention of the previously observed intratwin similarity of the recognition cues of twin lambs. The coherent manner in which these changes take place probably contributes to the cohesion in a flock of sheep.

Characterization of volatiles and aroma-active compounds in honeybush (Cyclopia subternata) by GC-MS and GC-O analysis.

Volatile organic compounds (VOCs) in fermented honeybush, Cyclopia subternata, were sampled by means of a high-capacity headspace sample enrichment probe (SEP) and analyzed by gas chromatography-mass spectrometry (GC-MS). Stereochemistry was determined by means of enantioselective GC-MS with derivatized ß-cyclodextrin columns as chiral selectors. A total of 183 compounds, the majority of which are terpenoids (103; 56%), were identified by comparing their mass spectra and retention indices with those of reference compounds or tentatively identified by comparison with spectral library or literature data. Of these compounds, 37 were determined by gas chromatography-olfactometry (GC-O), using detection frequency (DF) and aroma extract dilution analysis (AEDA), to be odor-active (FD ≥ 2). (E)-ß-Damascenone, (R/S)-linalool, (E)-ß-damascone, geraniol, (E)-ß-ionone, and (7E)-megastigma-5,7,9-trien-4-one were identified with the highest FD factors (≥512). The odors of certain compounds, that is, (6E,8Z)-megastigma-4,6,8-trien-3-one, (6E,8E)-megastigma-4,6,8-trien-3-one, (7E)-megastigma-5,7,9-trien-4-one, 10-epi-γ-eudesmol, epi-α-muurolol, and epi-α-cadinol, were perceived by GC-O assessors as typically honeybush-like.

Olfactory cue mediated neonatal recognition in sheep, Ovis aries.

The strong bond between ewe and lamb formed shortly after parturition is an important factor in lamb survival. Evidence exists that a ewe can distinguish her lamb by its unique smell, but the constituents of such a putative olfactory cue have not yet been identified. We have now identified 133 volatile organic compounds associated with the wool of Döhne Merino lambs that we presume may be involved in neonatal recognition. Quantitative analysis and comparison of odor profiles of the twins of 16 ewes (9.69% sample group) of a flock of 165 twin-bearing ewes revealed that the wool volatiles of twins are qualitatively and quantitatively similar, but differ from those of other twins or non-twin lambs in the flock. The 88 constituents present in at least 20% of the analyzed wool samples were considered as variables for multivariate analysis. A P-value < 0.001 was calculated, indicating that the pairing of twins according to the qualitative and quantitative composition of the wool was significant. Bioassays carried out during the lambing seasons of 2009 and 2010 confirmed the previously established role of lamb odor in ewe-lamb recognition. However, when alien lambs were dressed in jackets sprayed with synthetic mixtures formulated to match the chemical composition of the effluvia of the ewes' own lambs, ewes rejected the aliens. This is possibly because the VOCs were not released in quantitative ratios sufficiently accurate to emulate the odor of the ewes' own lambs.

Lizard epidermal gland secretions. II. Chemical characterization of the generation gland secretion of the sungazer, Cordylus giganteus.

In lizards, the epidermal glands of the femoral and precloacal regions are involved in the production of semiochemicals. In addition to its femoral glands, the giant girdled lizard, or sungazer, Cordylus giganteus, which is endemic to South Africa, has generation glands as an additional potential source of semiochemicals. These epidermal glands are described as glandular scales that overlay the femoral glands and are included in the normal epidermal profile located in the femoral (thigh) and anterior antebrachial (fore-leg) regions of the male sungazer. GC-MS analysis of the generation gland secretions and the trimethylsilyl derivatives of some of the steroidal constituents was employed to identify 59 constituents, including alkenes, carboxylic acids, alcohols, ketones, aldehydes, esters, amides, nitriles, and steroids. The quantitative differences of the volatile constituents of the fore- and hind-leg generation glands were compared between individuals. This is the first report on the chemical composition of generation glandular material of lizards.

Lizard epidermal gland secretions I: Chemical characterization of the femoral gland secretion of the sungazer, Cordylus giganteus.

The giant girdled lizard or sungazer, Cordylus giganteus, is endemic to South Africa. It has been suggested that in this species, as in other lizard species, epidermal glands in the femoral, pre-cloacal regions, and cloacal glands are the main sources of semiochemicals and that these secretions could play an important role at different levels of the social biology of the animals. To gain a better understanding of the nature of the femoral gland secretions of the sungazer, characterization of the constituents of the secretions was carried out. By using GC-MS analysis, in conjunction with auxiliary techniques, such as solventless sample introduction and trimethylsilyl derivatization, 53 relatively involatile compounds, including carboxylic acids, alcohols, ketones, esters, and steroids, were identified in the secretions of both sexes. The study showed that the secretions of male and female sungazers contain only semi-volatile chemicals.

Simplified analysis of organic compounds in headspace and aqueous samples by high-capacity sample enrichment probe.

A sample enrichment probe (SEP) consisting of a thin rod of an inert material and provided at one end with a short sleeve of polydimethylsilicone rubber was used for the high-capacity sample enrichment of analytes from gaseous and aqueous samples for analysis by gas chromatography (GC) and its hyphenated techniques. The silicone rubber was exposed to the analytical sample, after which the end of the rod carrying the silicone rubber was introduced into the injector and the analytes thermally desorbed and analysed by GC. This technique is similar to, but differs from, solid-phase microextraction (SPME) in that a much larger volume of the sorptive phase is employed, the sorptive phase is not introduced into the inlet of the GC via a needle and the injector is opened to the atmosphere for the introduction and removal of the SEP. In the determination of volatile and semi-volatile organic compounds in gaseous and aqueous media, the SEP technique gave results comparable with those obtained by the stir-bar-sorptive extraction (SBSE) and high-capacity sorption probe (HCSP) techniques. Implementation of the SEP technique requires only minor adaptations to the gas chromatograph and does not require any auxiliary thermal desorption and cryotrapping equipment.

Characterization of dog repellent factor from cuticular secretion of female yellow dog tick, Haemaphysalis leachi.

During its natural life cycle, the yellow dog tick, Haemaphysalis leachi, has three hosts, and it has to spend enough time on each of them to complete a blood meal. When irritated, the females of this tick species produce a cuticular secretion that contains a dog-repelling allomone. This improves the tick's chances of survival by deterring the dog from biting the tick off its body. Employing response-guided isolation techniques in conjunction with gas chromatography-mass spectrometry, the defensive allomone of H. leachi was found to consist of the six homologous aliphatic aldehydes from hexanal to undecanal. A mixture of synthetic versions of these six aldehydes in quantities corresponding to those secreted by one tick elicited strong aversion reactions in the majority of dogs of various breeds.

Elemental sulfur identified in urine of cheetah, Acinonyx jubatus.

The urine of the cheetah, Acinonyx jubatus, is almost odorless, and probably for this reason, it has not attracted much attention from scientists. Using gas chromatography-mass spectrometry, we identified 27 and 37 constituents in the headspace vapor of the urine of male and female cheetah, respectively. These constituents, composed of hydrocarbons, short-chain ethers, aldehydes, saturated and unsaturated cyclic and acyclic ketones, 2-acetylfuran, dimethyl disulfide, dimethyl sulfone, phenol, myristic acid (tetradecanoic acid), urea, and elemental sulfur, are all present in the headspace vapor in very small quantities; dimethyl disulfide is present in such a low concentration that it cannot be detected by the human nose. This is only the second example of elemental sulfur being secreted or excreted by an animal. It is hypothesized that the conversion of sulfur-containing compounds in the cheetah's diet to elemental sulfur and to practically odorless dimethyl sulfone enables this carnivore to operate as if "invisible" to the olfactory world of its predators as well as its prey, which would increase its chances of survival.