Basic HTML Version
taste gene variants including those for the ability to taste
propylthiouracil. The addition of sodium gluconate significantly
decreased the bitterness ratings for urea, caffeine, quinine
(p<0.001), marginally reduced ratings for DB (p=0.096) and did
not reduce ratings for propylthiouracil (p=0.59). For
propylthiouracil, the inability of the blocker to reduce bitterness
was not a floor effect among genetically insensitive people
[genotype x blocker; p=0.63]. A survey of the link between the
bitter compounds other than propylthiouracil and genetic variants
besides those within the TAS2R38 gene revealed an association
between the bitter receptor TAS2R60 (rs4595035) and the
bitterness of urea and quinine (p = 0.02), with an equal reduction in
bitter-blocking for all TAS2R60 genotype groups. We conclude that
(1) as previously reported, the effectiveness of sodium gluconate to
reduce bitterness depends on the particular compounds tested, (2)
bitter perception is related to receptor genotype more broadly than
the relationship between propylthiouracil and TAS2R38 variants,
and (3) sodium gluconate can reduce the bitterness of urea and
quinine regardless of TAS2R60 genotype. Acknowledgements:
This project was funded by R01 DC011287 and supported by P30
DC011735 from the National Institute on Deafness and Other
Communication Disorders. The content is solely the responsibility
of the authors and does not necessarily represent the official views
of the NIDCD or the National Institutes of Health.
#P202
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
Quantitative analysis for the masking effects to bitter taste
Takayuki Kawai, Yuko Kusakabe
National Food Research Institute Tsukuba, Japan
On behavior tests for taste evalutaion with mice, lick number to
the test solutions depends on their favorability. So, we analyzed the
favorability of various concentration of denatonium benzoate bitter
solution based on animal behavior. We also analyzed and quantified
the favorability changes when sodium saccharin as sweet
compound, mono-sodium glutamate as umami compound, or
sodium chloride as salty compound was added to the bitter test
solutions. As a result, the addition of 2.5 mM of sodium saccharin,
500 mM of mono-sodium glutamate, and 100 mM of sodium
chloride showed the ability to suppress bitter taste as 44%, 69%,
47%, respectively. These results suggest that the bitter masking
effects could be evaluated objectively by animal behavior, without
having human sensory evaluation by well-trained panelists.
#P203
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
Agonists and Antagonists of the Insect Odorant Receptor
Co-Receptor Subunit
Sisi Chen, Charles W. Luetje
Molecular & Cellular Pharmacology, University of Miami,
Miami, FL, USA
Insect odorant receptors (ORs) are odorant-gated ion channels,
consisting of two essential parts: an odorant binding subunit and a
co-receptor subunit (Orco). VUAA1 (CAS: 525582-84-7) was
recently identified as a novel OR agonist that acts directly on
Orco (Jones et al., 2011, PNAS 108: 8821-5). To identify additional
Orco ligands, we screened 22 compounds (termed Orco Ligand
Candidates, OLCs), some structurally related to VUAA1 (4-Ethyl-
1,2,4-triazol thioacetamide core with alterations to the pyridine and
phenyl rings) and some similar to portions of the VUAA1 structure.
We expressed heteromeric ORs, as well as individual Orcos, from
several species in
Xenopus
oocytes and assayed receptor function
by two-electrode voltage clamp electrophysiology. OLC3 (pyridine
nitrogen moved to the 4 position) and OLC12 (pyridine nitrogen in
the 4 position and a 4- isopropyl moiety on the phenyl ring)
were identified as agonists, able to activate several ORs:
DmelOr35a+DmelOrco, an OR from
Drosophila melanogaster
, as
well as DmelOrco expressed alone; CquiOr10+CquiOrco, an OR
from
Culex quinquefasciatus
(Southern House Mosquito), as well
as CquiOrco expressed alone; OnubOr1+OnubOrco, an OR from
Ostrinia nubilalis
(European Corn Borer), but not OnubOrco
expressed alone. We next identified several antagonists, each able
to inhibit OLC12 activation of DmelOr35a+DmelOrco, DmelOrco,
CquiOr10+CquiOrco and CquiOrco. Of particular interest was
OLC15 (pyridine nitrogen in the 2 position and a 4-butyl moiety on
the phenyl ring). Concentration-inhibition analysis of OLC15
inhibition of DmelOr35a+DmelOrco at different concentrations of
OLC12 demonstrated a competitive interaction. Our identification
of additional Orco agonists and antagonists provides new
experimental tools for the study of insect ORs. Acknowledgements:
NIH RO1DC011091
#P204
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
A systems-level analysis of odor coding in antenna of a
herbivorous insect, the Asian Citrus Psyllid
Iliano V. Coutinho-Abreu, Lisa Forster, Shane McInally,
Robert Luck, Anandasankar Ray
Department of Entomology, University of California
Riverside, CA, USA
The Asian Citrus Psyllid (ACP),
Diaphorina citri
, has a specialized
olfactory system, bearing less than a dozen putative olfactory
sensilla on the antenna, which encourages a systems-level approach
for complete characterization. Here, we present a systematic
characterization of the responses of the main olfactory sensilla, the
four Rhinarial Plate (RPs), to a panel of 120 odors using single-
sensillum electrophysiology and the annotation of the Odorant
Receptor (OR) and Ionotropic Receptor (IR) gene families.
Roughly, half of the odors induced either activation or inhibition of
specific Odorant Receptor Neurons (ORN). Each RP hosts three
ORNs of which the A ORNs respond specifically to amines, acids
and aldehydes, the hallmark of receptors encoded by IRs. The B
and C ORNs respond primarily to aliphatic and aromatic odorants,
with a variety of functional groups, that are hallmarks of receptors
encoded by the OR gene family. We are able to identify two
specific neurons that are broadly tuned to green leaf volatiles, and
another that is narrowly tuned to odors of the citrus flush shoots,
suggesting that these may participate in host-seeking behavior.
On the other hand, we have also identified neurons that are
activated by an ACP repellent. In regards to the annotation of genes
encoding ACP ORs and IRs, sixteen genes have been identified so
far, which is compatible with its limited olfactory system. Taken
together, the electrophysiological responses of 12 ACP OSNs
revealed a possible neuronal code controlling ACP attraction and
repellence, which is being further tested via behavioral studies.
Abstracts | 95
Abstracts are printed as submitted by the author(s)
P O S T E R P R E S E N T AT I O N S