| 1. |
- Arvidsson, Josefin, et al.
(författare)
-
Successful acquisition of an olfactory discrimination test by Asian elephants,Elephas maximus
- 2012
-
Ingår i: Physiology and Behavior. - : Elsevier. - 0031-9384 .- 1873-507X. ; 105:3, s. 809-814
-
Tidskriftsartikel (refereegranskat)abstract
- The present study demonstrates that Asian elephants, Elephas maximus, can successfully be trained to cooperatein an olfactory discrimination test based on a food-rewarded two-alternative instrumental conditioningprocedure. The animals learned the basic principle of the test within only 60 trials and readily mastered intramodalstimulus transfer tasks. Further, they were capable of distinguishing between structurally related odorstimuli and remembered the reward value of previously learned odor stimuli after 2, 4, 8, and 16 weeks ofrecess without any signs of forgetting. The precision and consistency of the elephants' performance in testsof odor discrimination ability and long-term odor memory demonstrate the suitability of this method forassessing olfactory function in this proboscid species. An across-species comparison of several measuresof olfactory learning capabilities such as speed of initial task acquisition and ability to master intramodalstimulus transfer tasks shows that Asian elephants are at least as good in their performance as mice, rats,and dogs, and clearly superior to nonhuman primates and fur seals. The results support the notion thatAsian elephants may use olfactory cues for social communication and food selection and that the sense ofsmell may play an important role in the control of their behavior.
|
|
| 2. |
- Güven, Selcuk Can, et al.
(författare)
-
Olfactory Sensitivity and Odor Structure-Activity Relationships for Aliphatic Carboxylic Acids in CD-1 Mice
- 2012
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3, s. e34301-
-
Tidskriftsartikel (refereegranskat)abstract
- Using a conditioning paradigm, the olfactory sensitivity of CD-1 mice for a homologous series of aliphatic n-carboxylic acids(ethanoic acid to n-octanoic acid) and several of their isomeric forms was investigated. With all 14 odorants, the animalssignificantly discriminated concentrations as low as 0.03 ppm (parts per million) from the solvent, and with four odorantsthe best-scoring animals even detected concentrations as low as 3 ppt (parts per trillion). Analysis of odor structure-activityrelationships showed that the correlation between olfactory detection thresholds of the mice for the unbranched carboxylicacids and carbon chain length can best be described as a U-shaped function with the lowest threshold values at n-butanoicacid. A significant positive correlation between olfactory detection thresholds and carbon chain length of the carboxylicacids with their branching next to the functional carboxyl group was found. In contrast, no such correlation was found forcarboxylic acids with their branching at the distal end of the carbon chain relative to the functional carboxyl group. Finally, asignificant correlation was found between olfactory detection thresholds and the position of the branching of the carboxylicacids. Across-species comparisons suggest that mice are more sensitive for short-chained (C2 to C4) aliphatic n-carboxylicacids than other mammalian species, but not for longer-chained ones (C5 to C8). Further comparisons suggest that odorstructure-activity relationships are both substance class- and species-specific.
|
|
| 3. |
- Karlsson, Anna-Carin, et al.
(författare)
-
Red junglefowl have individual body odors
- 2010
-
Ingår i: JOURNAL OF EXPERIMENTAL BIOLOGY. - : The Company of Biologists Ltd. - 0022-0949 .- 1477-9145. ; 213:10, s. 1619-1624
-
Tidskriftsartikel (refereegranskat)abstract
- Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.
|
|
| 4. |
- Kjeldmand, Luna, et al.
(författare)
-
Olfactory sensitivity for sperm-attractant aromatic aldehydes: a comparative study in human subjects and spider monkeys
- 2011
-
Ingår i: Journal of Comparative Physiology A. - : Springer. - 0340-7594 .- 1432-1351. ; 197, s. 15-23
-
Tidskriftsartikel (refereegranskat)abstract
- Using a three-alternative forced-choice ascendingstaircase procedure, we determined olfactory detectionthresholds in 20 human subjects for seven aromatic aldehydesand compared them to those of four spider monkeystested in parallel using an operant conditioning paradigm.With all seven odorants, both species detected concentrations\1 ppm, and with several odorants single individualsof both species even discriminated concentrations\1 ppbfrom the solvent. No generalizable species differences inolfactory sensitivity were found despite marked differencesin neuroanatomical and genetic features. The acrossodorantpatterns of sensitivity correlated significantlybetween humans and spider monkeys, and both specieswere more sensitive to bourgeonal than to lilial, cyclamal,canthoxal, helional, lyral, and 3-phenylpropanal. No significantcorrelation between presence/absence of an oxygen-containing moiety attached to the benzene ring orpresence/absence of an additional alkyl group next to thefunctional aldehyde group, and olfactory sensitivity wasfound in any of the species. However, the presence of atertiary butyl group in para position (relative to the functionalaldehyde group) combined with a lack of an additionalalkyl group next to the functional aldehyde groupmay be responsible for the finding that both species weremost sensitive to bourgeonal.
|
|
| 5. |
- Larsson, Jenny, et al.
(författare)
-
Gustatory responsiveness to the 20 proteinogenic amino acids in the spider monkey (Ateles geoffroyi)
- 2014
-
Ingår i: Physiology and Behavior. - : Elsevier. - 0031-9384 .- 1873-507X. ; 127, s. 20-26
-
Tidskriftsartikel (refereegranskat)abstract
- The gustatory responsiveness of four adult spider monkeys to the 20 proteinogenic amino acids was assessed in two-bottle preference tests of brief duration (1 min). We found that Ateles geoffroyi responded with significant preferences for seven amino acids (glycine, l-proline, l-alanine, l-serine, l-glutamic acid, l-aspartic acid, and l-lysine) when presented at a concentration of 100 mM and/or 200 mM and tested against water. At the same concentrations, the animals significantly rejected five amino acids (l-tryptophan, l-tyrosine, l-valine, l-cysteine, and l-isoleucine) and were indifferent to the remaining tastants. Further, the results show that the spider monkeys discriminated concentrations as low as 0.2 mM l-lysine, 2 mM l-glutamic acid, 10 mM l-proline, 20 mM l-valine, 40 mM glycine, l-serine, and l-aspartic acid, and 80 mM l-alanine from the alternative stimulus, with individual animals even scoring lower threshold values. A comparison between the taste qualities of the proteinogenic amino acids as described by humans and the preferences and aversions observed in the spider monkeys suggests a fairly high degree of agreement in the taste quality perception of these tastants between the two species. A comparison between the taste preference thresholds obtained with the spider monkeys and taste detection thresholds reported in human subjects suggests that the taste sensitivity of A. geoffroyi for the amino acids tested here might match that of Homo sapiens. The results support the assumption that the taste responses of spider monkeys to proteinogenic amino acids might reflect an evolutionary adaptation to their frugivorous and thus protein-poor diet.
|
|
| 6. |
- Larsson, Linda, et al.
(författare)
-
Ultra-high olfactory sensitivity for the human sperm-attractant aromaticaldehyde bourgeonal in CD-1 mice
- 2011
-
Ingår i: Neuroscience research. - : Elsevier Ireland Ltd and the Japan Neuroscience Society. - 0168-0102 .- 1872-8111. ; 71:4, s. 355-360
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies have shown that certain aromatic aldehydes are ligands for olfactory receptors expressedin mammalian sperm cells and induce sperm chemotaxis. Using a conditioning paradigm, the olfactorysensitivity of five CD-1 mice for seven aromatic aldehydes was investigated. With all seven stimuli, themice discriminated concentrations as low as 0.01 ppm (parts per million) from the solvent, and withbourgeonal the animals even detected concentrations as low as 0.1 ppq (parts per quadrillion) whichconstitutes the lowest olfactory detection threshold value reported in this species so far. The presence ofa tertiary butyl group in para-position (relative to the functional aldehyde group) combined with a lack ofan additional alkyl group next to the functional aldehyde group may be responsible for the extraordinarysensitivity of the mice for bourgeonal.
|
|
| 7. |
- Laska, Matthias, et al.
(författare)
-
How big is the gap between olfactory detection and recognition of aliphatic aldehydes?
- 2010
-
Ingår i: Attention, Perception, & Psychophysics. - - : The Psychonomic Society, Inc.. - 1943-393X. ; 72:3, s. 806-812
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to determine the magnitude of the difference in concentration between olfactory detection and recognition thresholds of aliphatic aldehydes. To this end, we first determined olfactory detection thresholds for n-butanal, n-pentanal, n-hexanal, n-heptanal, and n-octanal in a group of 16 subjects and then assessed their ability to discriminate between all possible binary pairs of the same odorants presented at different concentrations above their individual detection thresholds. We found that the gap between detection and recognition of aliphatic aldehydes is odorant pair dependent and, at the group level, spans at least a factor of 100. However, single subjects successfully discriminated between certain aldehyde pairs presented at a factor as low as 3 above detection threshold. Our approach to determining olfactory recognition thresholds, using a performance-based measure rather than verbal labeling, not only avoids the problem of semantic ambiguity and arguable criteria, but also is applicable to nonhuman species, allowing for interspecific comparisons of recognition thresholds and of the gap between detection and recognition of odorants. The raw discrimination data from this study are available as a supplement from http://app.psychonomic-journals.org/content/supplemental.
|
|
| 8. |
- Laska, Matthias, et al.
(författare)
-
Olfactory Discrimination of Aliphatic Odorants in South African Fur Seals (Arctocephalus pusillus)
- 2010
-
Ingår i: JOURNAL OF COMPARATIVE PSYCHOLOGY. - : American Psychological Association. - 0735-7036 .- 1939-2087. ; 124:2, s. 187-193
-
Tidskriftsartikel (refereegranskat)abstract
- Using a food-rewarded, two-choice, instrumental conditioning paradigm we assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between members of five chemical classes of aliphatic odorants presumed to differ in their abundance in the marine chemical environment. We found that the fur seals were able to distinguish between 24 of the 25 odor pairs presented and thus have a well-developed ability to discriminate between structurally related odorants, that aliphatic n-acetic esters were significantly more poorly discriminated by the fur seals than aliphatic n-aldehydes and n-carboxylic acids, and a lack of correlations between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length. These results suggest that the sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals. Further, they support the notion that regular connections between the perceived quality of odorants and their molecular structural properties are not a general phenomenon but appear to be odorant class- and species-specific. Our data support the hypothesis that a species chemical environment may affect its olfactory capabilities.
|
|
| 9. |
- Laska, Matthias
(författare)
-
Olfactory Perception of 6 Amino Acids by Human Subject
- 2010
-
Ingår i: Chemical Senses. - - : Oxford University Press. - 0379-864X .- 1464-3553. ; 35:4, s. 279-287
-
Tidskriftsartikel (refereegranskat)abstract
- The olfactory properties of 6 amino acids were assessed in 20 human subjects using psychophysical tests of detectability,discriminability, and chemesthesis. Mean olfactory detection thresholds were found to be 10 lM for D-methionine, 80 lM forL-methionine, 200 lM for L-cysteine, 220 lM for D-cysteine, 75 mM for D-proline, and 100 mM for L-proline. When presentedat clearly detectable and intensity-matched concentrations, the subjects readily discriminated between the odors of the L-formsof cysteine, methionine, and proline, whereas they failed to distinguish between the L- and D-forms of a given amino acid. Thesubjects also failed in localizing the side of monorhinal stimulation with all 6 amino acids when presented at the sameconcentrations as in the discrimination tasks. These results suggest that amino acids may contribute to the flavor of food notonly as taste stimuli but also as olfactory stimuli perceived via ortho- or retronasal smelling. In contrast, it is unlikely that aminoacids contribute to flavor perception via chemesthesis. Given that the odors of 4 of the 6 amino acids tested here weredetected at concentrations lower than their corresponding taste detection thresholds, this may have important implications forthe widespread use of amino acids as food additives as well as for the evaluation of off-flavors caused by amino acids.
|
|
| 10. |
- Laska, Matthias
(författare)
-
Olfactory Sensitivity and Odor Structure–Activity Relationships for Aliphatic Ketones in CD-1 Mice
- 2014
-
Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 39:5, s. 415-424
-
Tidskriftsartikel (refereegranskat)abstract
- Using a conditioning paradigm, the olfactory sensitivity of CD-1 mice for a homologous series of aliphatic 2-ketones(2-butanone to 2-nonanone) and several of their isomeric forms was investigated. With all 11 odorants, the animalssignificantly discriminated concentrations as low as 0.01 ppm (parts per million) from the solvent, and with two odorants(2-octanone and 5-nonanone), the best-scoring animals even detected concentrations as low as 3 ppt (parts per trillion).Analysis of odor structure–activity relationships showed that the correlation between olfactory detection thresholds of themice for the 2-ketones and carbon chain length can best be described as a U-shaped function with the lowest thresholdvalues at 2-octanone. Similarly, the correlation between olfactory sensitivity and carbon chain length of symmetricalketones (3-pentanone to 6-undecanone) can best be described as a U-shaped function. In contrast, no significantcorrelation was found between olfactory detection thresholds of the mice and position of the functional carbonyl groupattached to a C7 backbone. A comparison between the olfactory detection thresholds obtained here with those obtainedin earlier studies suggests that mice are significantly more sensitive for 2-ketones than for n-carboxylic acids of the samecarbon chain length. Across-species comparisons suggest that mice are significantly more sensitive for aliphatic ketonesthan squirrel monkeys and pigtail macaques, whereas the ranges of human olfactory detection threshold values overlapwith those of the mice with seven of the 11 ketones tested. Further comparisons suggest that odor structure–activityrelationships are both substance class and species specific.
|
|
| 11. |
- Laska, Matthias
(författare)
-
The Human Sense of Smell - Our Noses are Much Better that We Think!
- 2011
-
Ingår i: Senses and the City. - Wien : Lit Verlag. - 9783643502483 ; , s. 145-153
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The papers collected in this volume discuss the sensory dimension of cityscapes, with focus on touch and smell. Both have been traditionally considered "lower senses" and thus unworthy of being cultivated - objects of social prohibitions and targets of suppressing strategies in modern architecture and city planning. The book brings together approaches from anthropology, aesthetics, the theory of architecture, art and design research, psychophysiology, ethology, analytic chemistry, etc. (Series: Austria: Forschung und Wissenschaft - Interdisziplinar - Vol. 4)
|
|
| 12. |
- Linander, Nellie, et al.
(författare)
-
Olfactory Detectability of L-Amino Acids in the European Honeybee (Apis mellifera)
- 2012
-
Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 37:7, s. 631-638
-
Tidskriftsartikel (refereegranskat)abstract
- The honeybee is one of several insect model systems for the study of olfaction, yet our knowledge regarding the spectrum ofodorants detectable by Apis mellifera is limited. One class of odorants that has never been tested so far are the amino acids,which are important constituents of floral nectar. Using the proboscis extension response paradigm, we assessed whether theodor of amino acids is detectable for honeybees and determined olfactory detection thresholds for those amino acids that weredetectable. We found that honeybees are able to detect the odor of 5 of the 20 proteinogenic amino acids when presented ata concentration of 50 or 100 mM. Median olfactory detection thresholds for these 5 amino acids were 12.5 mM with L-tyrosineand L-cysteine, 50 mM with L-tryptophan and L-asparagine, and 100 mM with L-proline. All detection thresholds were muchhigher than reported concentrations of amino acids in floral nectars. We conclude that in the foraging and feeding context,honeybees are likely to detect amino acids through taste rather than olfaction. Across-species comparisons of the detectabilityof and sensitivity to amino acids suggest that the number of functional genes coding for olfactory receptors may affect botha species’ sensitivity for odorants and the breadth of its spectrum of detectable odorants.
|
|
| 13. |
- Løtvedt, Pia Katrine, et al.
(författare)
-
Olfactory sensitivity for "green odors" (Aliphatic C6 Alcohols and C6 aldehydes) - A comparative study in male CD-1 mice (Mus musculus) and female spides monkeys (Ateles geoffroyi)
- 2012
-
Ingår i: Pharmacology, Biochemistry and Behavior. - : Elsevier. - 0091-3057 .- 1873-5177. ; 101:3, s. 450-457
-
Tidskriftsartikel (refereegranskat)abstract
- Using a conditioning paradigm, the olfactory sensitivity of six male CD-1 mice for “green odors”, a group of eightstructurally related aliphatic C6 alcohols and aldehydes known to exert anxiolytic and stress-reducing effects,was investigated. With all eight stimuli, the animals discriminated concentrations!0.03 ppm(parts per million)from the solvent, and with three of the eight stimuli the best-scoring animals were even able to detect concen-trations !0.03 ppb (parts per billion). Three female spider monkeys tested in parallel were found to detect thesame eight stimuli at concentrations b1 ppm, and with six of the eight stimuli the best-scoring animals detectedconcentrations !0.1 ppm. Analysis of odor structure–activity relationships showed that in both species the typeof functional group attached to the aliphatic C6 backbone of the odorant molecules systematically affected theirolfactory sensitivity whereas the presence/absence of a double bond did not. In the mice, but not in the spidermonkeys, the position of a double bond and the cis/trans-configuration of the odorant molecules also had a sys-tematic effect on detectability of the “green odors”. A comparison of the detection thresholds between the twospecies tested here and those obtained in human subjects suggests that the number of functional olfactory recep-tor genes is a poor predictor of a species' olfactory sensitivity for “green odors”.
|
|
| 14. |
- Nilsson, Sara, 1981-, et al.
(författare)
-
Behavioral Responses to Mammalian Blood Odor and a Blood Odor Component in Four Species of Large Carnivores
- 2014
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:11
-
Tidskriftsartikel (refereegranskat)abstract
- Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals asthe whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles inmammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical ‘‘metallic, blood-like’’ odor quality in humans. We therefore assessed the behavior of captiveAsian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), andSiberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalianblood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruityodor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayedsignificantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, whenthey were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Mostimportantly, no significant differences were found in the number of interactions with the wooden logs impregnated withmammalian blood and the blood odor component in any of the four species. Only one of the four species, the SouthAmerican bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the fivesessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can beas efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a ‘‘character impact compound’’ of mammalian blood odor. Further, the resultssuggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.
|
|
| 15. |
|
|
| 16. |
- Olsson, Peter, et al.
(författare)
-
Human Male Superiority in Olfactory Sensitivity to the Sperm Attractant Odorant Bourgeonal
- 2010
-
Ingår i: Chemical Senses. - Oxford : Oxford University Press. - 0379-864X .- 1464-3553. ; 35:5, s. 427-432
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies have shown that sperm chemotaxis critically involves the human olfactory receptor OR1D2, which is activated bythe aromatic aldehyde bourgeonal. Given that both natural and sexual selection may act upon the expression of receptors, wehypothesized that human males are more sensitive than human females for bourgeonal. Using a 3-alternative forced-choicetest procedure, olfactory detection thresholds were determined for a total of 500 subjects, 250 males, and 250 femalesbetween 18 and 40 years of age. We found that male subjects detected bourgeonal at significantly lower concentrations(mean value: 13 ppb) compared with female subjects (mean value: 26 ppb), whereas no such gender difference in olfactorysensitivity was found with helional, a structural analog of bourgeonal, and with n-pentyl acetate, an aliphatic ester, which weretested in parallel. Males and females did not differ in their frequency of specific anosmia for any of the 3 odorants. Thefrequency distributions of olfactory detection thresholds were monomodal with all 3 odorants in both genders. Olfactorydetection thresholds did not differ significantly between pre- and postovulatory females with any of the 3 odorants. To the bestof our knowledge, this is the first study ever to find a human male superiority in olfactory sensitivity. Single nucleotidepolymorphisms and/or copy number variations in genes coding for olfactory receptors may be the proximate cause for ourfinding, whereas a gender difference in the behavioral relevance of bourgeonal may be the ultimate cause.
|
|
| 17. |
|
|
| 18. |
- Phillips, Matthew, et al.
(författare)
-
Olfactory and Visuospatial Learning and MemoryPerformance in Two Strains of Alzheimer’s DiseaseModel Mice—A Longitudinal Study
- 2011
-
Ingår i: PLoS ONE. - : PLoS ONE. - 1932-6203. ; 6:5, s. e19567-
-
Tidskriftsartikel (refereegranskat)abstract
- Using a longitudinal study design, two strains of Alzheimer’s disease (AD) model mice, one expressing b-amyloid plaquesand one expressing Tau protein-associated neurofibrillary tangles were assessed for olfactory and visuospatial learning andmemory and their performance compared to that of age-matched controls. No significant difference between AD andcontrol mice was found in the initial set of olfactory tasks performed at 6 months of age whereas both strains of AD miceperformed significantly poorer than the controls in visuospatial learning at this age. Subsequent tests performed on thesame individual animals at 7, 8, 9, 11, 13, 15, and 18 months of age also failed to find systematic differences in olfactoryperformance between AD and control mice. In contrast, the AD mice performed consistently poorer than the controls invisuospatial re-learning tests performed at these ages. With most olfactory tasks, both AD and control mice displayed amarked decrease in performance between testing at 15 and 18 months of age. These results show that the two strains of ADmodel mice do not display an olfactory impairment in a time course consistent with human AD, but are impaired invisuospatial capabilities. The marked age-related changes observed with the olfactory tasks in both AD and control micesuggest that the observed lack of an AD-related olfactory impairment is not due to an insensitivity of the tests employed.Rather, they suggest that the olfactory system of the two AD mouse model strains may be surprisingly robust against ADtypicalneuropathologies.
|
|
| 19. |
- Rizvanovic, Alisa, et al.
(författare)
-
Olfactory Discrimination Ability of Asian Elephants (Elephas maximus) forStructurally Related Odorants
- 2013
-
Ingår i: Chemical Senses. - Oxford : Oxford University Press. - 0379-864X .- 1464-3553. ; 38:2, s. 107-118
-
Tidskriftsartikel (refereegranskat)abstract
- Using a food-rewarded two-choice instrumental conditioning paradigm, we assessed the ability of Asian elephants, Elephasmaximus, to discriminate between 2 sets of structurally related odorants. We found that the animals successfully discriminatedbetween all 12 odor pairs involving members of homologous series of aliphatic 1-alcohols, n-aldehydes, 2-ketones,and n-carboxylic acids even when the stimuli differed from each other by only 1 carbon. With all 4 chemical classes, the elephantsdisplayed a positive correlation between discrimination performance and structural similarity of odorants in terms ofdifferences in carbon chain length. The animals also successfully discriminated between all 12 enantiomeric odor pairs tested.An analysis of odor structure–activity relationships suggests that a combination of molecular structural properties rather thana single molecular feature may be responsible for the discriminability of enantiomers. Compared with other species testedpreviously on the same sets of odor pairs (or on subsets thereof), the Asian elephants performed at least as well as miceand clearly better than human subjects, squirrel monkeys, pigtail macaques, South African fur seals, and honeybees. Furthercomparisons suggest that neither the relative nor the absolute size of the olfactory bulbs appear to be reliable predictors ofbetween-species differences in olfactory discrimination capabilities. In contrast, we found a positive correlation between thenumber of functional olfactory receptor genes and the proportion of discriminable enantiomeric odor pairs. Taken together,the results of the present study support the notion that the sense of smell may play an important role in regulating thebehavior of Asian elephants.
|
|
| 20. |
- Sarrafchi, Amir, et al.
(författare)
-
Olfactory Sensitivity for Six Predator Odorants in CD-1Mice, Human Subjects, and Spider Monkeys
- 2013
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:11, s. e80621-
-
Tidskriftsartikel (refereegranskat)abstract
- Using a conditioning paradigm, we assessed the olfactory sensitivity of six CD-1 mice (Mus musculus) for six sulfurcontainingodorants known to be components of the odors of natural predators of the mouse. With all six odorants, themice discriminated concentrations ,0.1 ppm (parts per million) from the solvent, and with five of the six odorants the bestscoringanimals were even able to detect concentrations ,1 ppt (parts per trillion). Four female spider monkeys (Atelesgeoffroyi) and twelve human subjects (Homo sapiens) tested in parallel were found to detect the same six odorants atconcentrations ,0.01 ppm, and with four of the six odorants the best-scoring animals and subjects even detectedconcentrations ,10 ppt. With all three species, the threshold values obtained here are generally lower than (or in the lowerrange of) those reported for other chemical classes tested previously, suggesting that sulfur-containing odorants may play aspecial role in olfaction. Across-species comparisons showed that the mice were significantly more sensitive than the humansubjects and the spider monkeys with four of the six predator odorants. However, the human subjects were significantlymore sensitive than the mice with the remaining two odorants. Human subjects and spider monkeys significantly differed intheir sensitivity with only two of the six odorants. These comparisons lend further support to the notion that the number offunctional olfactory receptor genes or the relative or absolute size of the olfactory bulbs are poor predictors of a species’olfactory sensitivity. Analysis of odor structure–activity relationships showed that in both mice and human subjects the typeof alkyl rest attached to a thietane and the type of oxygen moiety attached to a thiol significantly affected olfactorysensitivity.
|
|
| 21. |
- Sunghee, Kim, et al.
(författare)
-
Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers
- 2013
-
Ingår i: Journal of Comparative Physiology A. Sensory, neural, and behavioral physiology. - : Springer. - 0340-7594 .- 1432-1351. ; 199:6, s. 535-544
-
Tidskriftsartikel (refereegranskat)abstract
- Using a food-rewarded two-choice instrumentalconditioning paradigm we assessed the ability of SouthAfrican fur seals, Arctocephalus pusillus, to discriminatebetween 12 enantiomeric odor pairs. The results demonstratethat the fur seals as a group were able to discriminatebetween the optical isomers of carvone, dihydrocarvone,dihydrocarveol, menthol, limonene oxide, a-pinene,fenchone (all p\0.01), and b-citronellol (p\0.05),whereas they failed to distinguish between the (?)- and(-)-forms of limonene, isopulegol, rose oxide, and camphor(all p[0.05). An analysis of odor structure–activityrelationships suggests that a combination of molecularstructural properties rather than a single molecular featuremay be responsible for the discriminability of enantiomericodor pairs. A comparison between the discrimination performanceof the fur seals and that of other species testedpreviously on the same set of enantiomers (or subsetsthereof) suggests that the olfactory discrimination capabilitiesof this marine mammal are surprisingly well developedand not generally inferior to that of terrestrial mammalssuch as human subjects and non-human primates. Further,comparisons suggest that neither the relative nor the absolutesize of the olfactory bulbs appear to be reliable predictorsof between-species differences in olfactorydiscrimination capabilities. Taken together, the results ofthe present study support the notion that the sense of smellmay play an important and hitherto underestimated role inregulating the behavior of fur seals.
|
|
| 22. |
- Wallén, Helena, et al.
(författare)
-
Olfactory sensitivity for six amino acids : a copmarative study in CD-1 mice and spider monkeys
- 2012
-
Ingår i: Amino Acids. - : Springer. - 0939-4451 .- 1438-2199. ; 42:4, s. 1475-1485
-
Tidskriftsartikel (refereegranskat)abstract
- Using a conditioning paradigm, the olfactorysensitivity of five CD-1 mice for the L- and D-forms ofcysteine, methionine, and proline was investigated. With allsix stimuli, the animals discriminated concentrationsB0.1 ppm (parts per million) from the odorless solvent, andwith three of the six stimuli the best-scoring animals wereeven able to detect concentrations\0.1 ppb (parts per billion).Three spider monkeys tested in parallel were found todetect the same six stimuli at concentrations\1 ppm, andwith four of the six stimuli the best-scoring animalsdetected concentrations B1 ppb. Both CD-1 mice and spidermonkeys displayed a higher olfactory sensitivity withthe L- and D-forms of cysteine and methionine than with theprolines, suggesting an important role of the sulfur-containingfunctional groups for detectability. Accordingly, theacross-odorant patterns of detection thresholds obtainedwith mice and spider monkeys showed a significant positivecorrelation. A comparison of the detection thresholdsbetween the two species tested here and those obtained inhuman subjects suggests that neither the number of functionalolfactory receptor genes nor the absolute or the relativesize of the olfactory bulbs reliably predicts a species’olfactory sensitivity for amino acids.
|
|
