The characteristic response of domestic cats to plant iridoids allows them to gain chemical defense against mosquitoes

ネコのマタタビ反応の謎を解明 --マタタビ反応はネコが蚊を忌避するための行動だった--. 京都大学プレスリリース. 2021-01-21.Domestic cats and other felids rub their faces and heads against catnip (Nepeta cataria) and silver vine (Actinidia polygama) and roll on the ground as a characteristic response. While this response is well known, its biological function and underlying mechanism remain undetermined. Here, we uncover the neurophysiological mechanism and functional outcome of this feline response. We found that the iridoid nepetalactol is the major component of silver vine that elicits this potent response in cats and other felids. Nepetalactol increased plasma β-endorphin levels in cats, while pharmacological inhibition of μ-opioid receptors suppressed the classic rubbing response. Rubbing behavior transfers nepetalactol onto the faces and heads of respondents where it repels the mosquito, Aedes albopictus. Thus, self-anointing behavior helps to protect cats against mosquito bites. The characteristic response of cats to nepetalactol via the μ-opioid system provides an important example of chemical pest defense using plant metabolites in nonhuman mammals

Asymmetric synthesis of 3-azide-4-fluoro-l-phenylalanine

<div><p>The asymmetric synthesis of <i>N</i>-Fmoc-protected 3-azide-4-fluoro-l-phenylalanine as a photoactive phenylalanine analog has been achieved by Schöllkopf’s alkylation.</p></div

An Improved Synthesis of (−)-5,11-Dideoxytetrodotoxin

We describe an improved synthesis of (−)-5,11-dideoxytetrodotoxin from an enone, which was used for synthesis of tetrodotoxin and its analogues in this laboratory. One of the major modifications was to establish a two-step guanidinylation of trichloroacetamide of a highly functionalized intermediate, which allowed us to prepare ¹⁵N₂-labeled 5,11-dideoxytetrodotoxin for biosynthetic investigations

Domestic cat damage to plant leaves containing iridoids enhances chemical repellency to pests

Catnip (Nepeta cataria) and silver vine (Actinidia polygama) produce iridoids with arthropod-repellent effects. Cats rub and roll against these plants, transferring iridoids to their fur that repels mosquitoes. Cats also lick and chew plant leaves during this response, although the benefit of this additional behavior has remained unknown. Here, we show that feline leaf damage substantially increases iridoid emission from both plants while also diversifying iridoids in silver vine. Cats show an equivalent duration of response to the complex cocktail of iridoids in damaged silver vine and to the much higher level of a single iridoid produced by damaged catnip. The more complex iridoid cocktail produced when silver vine is licked and chewed by cats increases mosquito repellency at low concentration. In conclusion, feline leaf damage contributes by releasing more mosquito-repellent iridoids. Feline olfactory and behavioral sensitivity is fine-tuned to plant-specific iridoid production for maximizing the mosquito repellency gained

Stereocontrolled Synthesis of an Indole Moiety of Sespendole and Stereochemical Assignment of the Side Chain

Two possible diastereomers of the indole moiety of sespendole were synthesized from 3-hydroxy-4-nitrobenzaldehyde in a highly stereoselective manner. Comparison of ¹H and ¹³C NMR spectra of the two synthetic materials with those sespendole leads us to propose that the relative stereochemistry of the epoxyalcohol is <i>syn</i>

Stereocontrolled Synthesis of an Indole Moiety of Sespendole and Stereochemical Assignment of the Side Chain

Two possible diastereomers of the indole moiety of sespendole were synthesized from 3-hydroxy-4-nitrobenzaldehyde in a highly stereoselective manner. Comparison of ¹H and ¹³C NMR spectra of the two synthetic materials with those sespendole leads us to propose that the relative stereochemistry of the epoxyalcohol is <i>syn</i>

First Detection of Tetrodotoxins in the Cotylean Flatworm Prosthiostomum trilineatum

Several polyclad flatworm species are known to contain high levels of tetrodotoxin (TTX), but currently TTX-bearing flatworms seem to be restricted to specific Planocera lineages belonging to the suborder Acotylea. During our ongoing study of flatworm toxins, high concentrations of TTXs were detected for the first time in the flatworm Prosthiostomum trilineatum, suborder Cotylea, from the coastal area of Hayama, Kanagawa, Japan. Toxin levels were investigated by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS), revealing that this species contains comparable concentrations of toxins as seen in planocerid flatworms such as Planocera multitentaculata. This finding indicated that there may be other species with significant levels of TTXs. The distribution of TTXs among other flatworm species is thus of great interest