Many apparently achiral organic molecules on Earth may be chiral because of random substitution of the 1.11% naturally abundant 13C for 12C in an enantiotopic moiety within the structure. However, chirality from this source is experimentally difficult to discern because of the very small difference between 13C and 12C. We have demonstrated that this small difference can be amplified to an easily seen experimental outcome using asymmetric autocatalysis. In the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc, addition of chiral molecules in large enantiomeric excess that are, however, chiral only by virtue of isotope substitution causes a slight enantiomeric excess in the zinc alkoxide of the produced pyrimidyl alkanol. Asymmetric autocatalysis then leads to pyrimidyl alcohol with a large enantiomeric excess. The sense of enantiomeric excess of the product alcohol varies consistently with the sense of the excess enantiomer of the carbon isotopically chiral compound.

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Chiral discrimination of saturated hydrocarbons has been very difficult to establish, or has not been possible at all. The first chiral discrimination of cryptochiral 5-ethyl-5-propylundecane 1, that is, (n-butyl)ethyl(n-hexyl)(n-propyl)methane, a chiral saturated quaternary hydrocarbon, which is known to exhibit practically no detectable value of optical rotation between 280 and 580 nm, has been accomplished by asymmetric autocatalysis of pyrimidyl alkanol. The absolute configuration of 1 has been determined. In the presence of (R)- or (S)-1, the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc affords (S)- and (R)-pyrimidyl alkanol with 91-97% ee, respectively. Thus, asymmetric autocatalysis serves as a powerful tool for the chiral discrimination of saturated hydrocarbons.

In order to examine the involvement of corticotropin-releasing hormone (CRF) receptor in the formation of anxiety, we investigated whether CRF receptor antagonist CP-154,526 suppressed conditioned fear stress. First, rats were individually subjected to 30 min of footshock. Twenty-four hours after footshock, the rats were again placed in the chamber and observed for 5 min without shock. CP-154,526 was administered 30 min before placing the rats in the chamber again. After that, CP-154,526 was once more administered 30 min before applying footshock. Administration of CP-154,526 30 min both before conditioned fear stress (placing the rats inside the cage but not applying footshock) and before actual footshock significantly reduced freezing behavior. These results show that CP-154,526 blocked both the acquisition and expression of conditioned fear, thus suggesting that the CRF receptor might be related to anxiety.

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Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We hypothesized that MS induces expression of osteoclastogenesis-associated chemokines in PDL tissue, resulting in chemotaxis and osteoclastogenesis during occlusal traumatism. We examined the effect of MS on relationships between chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models. In an in vitro model, intermittent stretching-induced MS was shown to up-regulate the expression of CC chemokine ligand (CCL)2, CCL3, and CCL5 in PDL cells. The expression levels of CCL2 in PDL tissues, its receptor CCR2 in pre-osteoclasts, and tartrate-resistant acid-phosphatase-positive cells in alveolar bone were significantly up-regulated 4-7 days after excessive MS during hyperocclusion in in vivo rodent models. Hyperocclusion predominantly induced CCL2 expression in PDL tissues and promoted chemotaxis and osteoclastogenesis, leading to MS-dependent alveolar bone destruction during occlusal traumatism.

Theobroxide is an epoxy cyclohexene compound isolated from the culture filtrate of the fungus Lasiodiplodia theobromae that induces potato microtuber formation in vitro (Nakamori and others 1994). When sprayed on potato (Solanum tuberosum L.) and morning glory (Pharbitis nil) plants, which require short days to induce tubers and flower buds, respectively, potato plants kept in noninducing conditions (long days) produced tubers. Theobroxide spray treatment also produced flower buds in morning glory plants kept under noninducing conditions (long days). Furthermore, under inducing conditions (short days), the number of flowers of seedlings sprayed with theobroxide was about 1.5 times that of controls.

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