Relationship between mood change, odour and its physiological effects in humans while inhaling the fragrances of essential oils as well as linalool and its enantiomers.

Humans can detect and discriminate a vast number of odours. The number perceived as distinguishable is estimated to be more than ten thousand. Humans are capable of distinguishing even slight alterations in the structure of an odorous molecule. A pair of enantiomers of an odorant, which possess the same molecular structures except for the chiral position, can trigger profoundly different odour perceptions. How precisely can humans and their olfactory system detect and discriminate such a great variety of odours and such subtle differences in the molecular structures? In a series of studies, we have attempted to examine the relationship between mood change, odour and its physiological effects, by focusing on the possible verbal and non-verbal changes in humans induced by smelling the fragrances of essential oils as well as linalool and its enantiometric isomers. In this article, we provide an overview of our recent verbal and non-verbal studies. We then discuss how our findings may contribute to the assessment of psychophysiological responses of essential oils as well as how our research can contribute to the study of human chemoreception science, by shedding light on the sophistication of the olfactory system in its ability to detect and discriminate odors.

Identification and characterization of antimicrobial peptides from the skin of the endangered frog Odorrana ishikawae.

The endangered anuran species, Odorrana ishikawae, is endemic to only two small Japanese Islands, Amami and Okinawa. To assess the innate immune system in this frog, we investigated antimicrobial peptides in the skin using artificially bred animals. Nine novel antimicrobial peptides containing the C-terminal cyclic heptapeptide domain were isolated on the basis of antimicrobial activity against Escherichia coli. The peptides were members of the esculentin-1 (two peptides), esculentin-2 (one peptide), palustrin-2 (one peptide), brevinin-2 (three peptides) and nigrocin-2 (two peptides) antimicrobial peptide families. They were named esculentin-1ISa, esculentin-1ISb, esculentin-2ISa, palustrin-2ISa, brevinin-2ISa, brevinin-2ISb, brevinin-2ISc, nigrocin-2ISa and nigrocin-2ISb. Peptide primary structures suggest a close relationship with the Asian odorous frogs, Odorrana grahami and Odorrana hosii. These antimicrobial peptides possessed a broad-spectrum of growth inhibition against five microorganisms (E. coli, Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis and Candida albicans). Nine different cDNAs encoding the precursor proteins were also cloned and showed that the precursor proteins exhibited a signal peptide, an N-terminal acidic spacer domain, a Lys-Arg processing site and an antimicrobial peptide at the C-terminus.

Molecular biosensing mechanisms in the spleen for the removal of aged and damaged red cells from the blood circulation.

Heinz bodies are intraerythrocytic inclusions of hemichrome formed as a result of hemoglobin (Hb) oxidation. They typically develop in aged red cells. Based on the hypothesis that hemichrome formation is an innate characteristic of physiologically normal Hb molecules, we present an overview of our previous findings regarding the molecular instability of Hb and the formation of hemichrome, as well as recent findings on Heinz body formation within normal human erythrocytes. Human adult Hb (HbO(2) A) prepared from healthy donors showed a tendency to produce hemichrome, even at close to physiological temperature and pH. Recent studies found that the number of Heinz bodies formed in red cells increased with increasing temperature when freshly drawn venous blood from healthy donors was subjected to mild heating above 37 °C. These findings suggest that Hb molecules control the removal of non-functional erythrocytes from the circulation via hemichrome formation and subsequent Heinz body clustering. In this review, we discuss the molecular biosensing mechanisms in the spleen, where hemichrome formation and subsequent Heinz body clustering within erythrocytes play a key role in the removal of aged and damaged red cells from the blood circulation.

Use of human senses as sensors.

This paper is an overview of our recent findings obtained by the use of human senses as sensors, suggesting that human senses might be indispensable sensors, not only for practical uses but also for gaining a deeper understanding of humans. From this point of view, two kinds of studies, both based on semantic responses of participants, deserve emphasis. One study assessed the efficacy of the photocatalytic elimination of stains or bio-aerosols from an air environment using TiO(2) as well as the photocatalytic deodorizing efficacy of a TiO(2)-type deodorizer; the other study evaluated the changes in perception of a given aroma while inhaling the fragrance of essential oils. In the latter study, we employed a sensory test for evaluating changes in perception of a given aroma. Sensory tests were conducted twice, when participants were undergoing the Kraepelin mental performance test (mental arithmetic) or an auditory task (listening to environmental natural sounds), once before the task (pre-task) and once after the task (post-task). The perception of fragrance was assessed by 13 contrasting pairs of adjectives as a function of the task assigned to participants. The obtained findings illustrate subtle nuances regarding how essential oils manifest their potency and how olfactory discrimination and responses occur in humans.

cDNA cloning of a mannose-binding lectin-associated serine protease (MASP) gene from hagfish (Eptatretus burgeri).

Hagfish, agnathan cyclostome, is the most primitive extant vertebrate and its complement (C) system seems to be a primordial system in comparison with a well-developed C system in gnathostome vertebrates. From a phylogenic perspective of defense mechanisms, we have isolated complement C3 from the serum of hagfish (Eptatretus burgeri). In this study, we first attempted to identify a hagfish Bf or C2 as a C3 convertase by RT-PCR using degenerative primers designed on the basis of the conserved amino acid stretches among the several kinds of serine proteases. Contrary to our expectation, homology search of cloned RT-PCR product suggested that there was a partial cDNA encoding the homologue of neither Bf nor C2 but a mannose-binding lectin-associated serine protease (MASP). Analyses of a full-length cDNA clone isolated from a hagfish liver cDNA library by using the partial cDNA as a probe indicated that this cDNA encoded hagfish MASP 1. This evidence strongly suggests that the hagfish defends itself against pathogens at least by the complement system composed of lectin pathway.

Effects on humans elicited by inhaling the fragrance of essential oils: sensory test, multi-channel thermometric study and forehead surface potential wave measurement on basil and peppermint.

The effects on humans inhaling the fragrance of essential oils were examined in terms of a sensory test, a multi-channel skin thermometer study and a portable forehead surface electroencephalographic (IBVA-EEG) measurement. The essential oils examined in this study were those of basil and peppermint, because our previous sensory test had indicated an opposite effect of these essential oils when mental work was undertaken; the inhalation of basil produced a more favorable impression after work than before work, whereas peppermint produced an unfavorable impression under these circumstances. For subjects administered basil or peppermint before and after mental work using an inhalator, a series of multi-channel skin thermometer studies and IBVA-EEG measurements were conducted. Using such paired odorants, our results showed that when compared between before and after mental work assigned to subjects: (1) the inhalation of basil, in which a favorable impression was predominant on the whole in terms of the sensory evaluation spectrum, was shown to be associated upward tendency in finger-tip skin temperature; (2) whereas these situations were opposite in the case of peppermint, in which the reversed (unfavorable) feature in sensory profiling was accompanied by a decrease in the magnitude of beta waves and a decrease in the finger-tip skin temperature both based on Welch's method, even at p < 0.01, implying a decreasing propensity of the aroused state and of the arousal response. The elucidation of such sensory and physiological endpoints of paired odorants would be of primary importance for human chemoreception science, because these are only rarely recorded during the same experiments, and this paradigm is highly informative about non-verbal responses to odorants.

The alpha 1 beta 1 contact of human hemoglobin plays a key role in stabilizing the bound dioxygen.

When the alpha and beta chains were separated from human oxyhemoglobin (HbO(2)), each individual chain was oxidized easily to the ferric form, their rates being almost the same with a very strong acid-catalysis. In the HbO(2) tetramer, on the other hand, both chains become considerably resistant to autoxidation over a wide range of pH values (pH 5-11). Moreover, HbA showed a biphasic autoxidation curve containing the two rate constants, i.e. k(f) for the fast oxidation due to the alpha chains, and k(s) for the slow oxidation to the beta chains. The k(f)/k(s) ratio increased from 3.2 at pH 7.5-7.3 at pH 5.8, but became 1 : 1 at pH values higher than 8.5. In the present work, we used the valency hybrid tetramers such as (alpha(3+))2(beta O(2))(2) and (alpha O(2)(2)(beta(3+))(2), and demonstrated that the autoxidation rate of either the alpha or beta chains (when O2- ligated) is independent of the valency state of the corresponding counterpart chains. From these results, we have concluded that the formation of the alpha 1 beta 1 or alpha 2 beta 2 contact suppresses remarkably the autoxidation rate of the beta chain and thus plays a key role in stabilizing the HbO(2) tetramer. Its mechanistic details were also given in terms of a nucleophilic displacement of O(2)(-) from the FeO(2) center, and the emphasis was placed on the proton-catalyzed process performed by the distal histidine residue.