Characteristics of urine spraying and scraping the ground with hind paws as scent-marking of captive cheetahs (Acinonyx jubatus)

Olfactory communication is common in felids. We observed two scent-markings, urine spraying and scraping the ground with hind paws during excretion, of 25 captive cheetahs. We analyzed the association of sniffing with the timing of urine spraying and scraping, and differences in these behaviors based on sex, age, and captive environment to understand the olfactory communication among cheetahs. Both scent-markings were strongly associated with sniffing, especially scraping, and the presence or absence of scent was thought to be a trigger. Both behaviors were observed only in adults; scraping was observed only in males. To our knowledge, this study was first to confirm the discharge of secretions from the anal glands during scraping. The frequencies of both behaviors were significantly higher in males kept in shared enclosures containing other individuals than in males kept in monopolized enclosures, while there was no difference in the frequencies among females. Female cheetahs are solitary and have non-exclusive home range, whereas male cheetahs are either solitary or live in coalition groups and there are territorial and non-territorial males. Our results could be attributed to the differences in sociality between the sexes and effect of the living environment

Effect of Cavity Size of Mesoporous Silica on Short DNA Duplex Stability

We studied the stabilities of short (4- and 3-bp) DNA duplexes within silica mesopores modified with a positively charged trimethyl aminopropyl (TMAP) monolayer (BJH pore diameter 1.6–7.4 nm). The DNA fragments with fluorescent dye were introduced into the pores, and their fluorescence resonance energy transfer (FRET) response was measured to estimate the structuring energies of the short DNA duplexes under cryogenic conditions (temperature 233–323 K). The results confirmed the enthalpic stability gain of the duplex within size-matched pores (1.6 and 2.3 nm). The hybridization equilibrium constants found for the size-matched pores were 2 orders of magnitude larger than those for large pores (≥3.5 nm), and this size-matching effect for the enhanced duplex stability was explained by a tight electrostatic interaction between the duplex and the surface TMAP groups. These results indicate the requirement of the precise regulation of mesopore size to ensure the stabilization of hydrogen-bonded supramolecular assemblies