The concept of information and expression of organic molecules is proposed. The polymeric chains of proteins may be replaced by steroidal molecules composed of skeletons with both many hydogen bonding groups and exchangeable pendant groups. Such small molecules form characteristic bilayered assemblies. A number of observation give us an idea that the molecules can express their information through the assemblies. The one is that the stacking modes and the hydrogen bonding network are greatly varied. Another is their guest-responsive structural changes which enable us to observe intercalation phenomena in organic crystals. Selective incorporation and reaction of the guest components provide us another important proof.

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Na⁺/glutamate, Na⁺/proline and H⁺/lactose transport systems in Escherichia coli are typical secondary active transport systems. On the basis of the properties of substrate binding to carriers, the ordered binding model for the mechanistic mechanism of the energy coupling was proposed, which was shown to explain well the transport properties of these secondary active transport systems. The specific properties of these transport systems were also summarized and shown to be explained by assuming special conditions within the framework of this general ordered binding model. Since many possible mechanisms for secondary active transport systems seem in general to be ruled out by the ordered binding mechanism, this mechanism probably has some biological significance. Thus, I propose that, for the same reason, other possible energy transducing machineries could also be ruled by this ordered binding mechanism.

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Photoreceptors adapt to light intensities over the range of 6-7 log units and cover extremely wide range of light intensities: usual chemical reactions, for example a Michaelis-Menten-type enzyme reaction, saturate over the range of -3 log units of substrate concentration. Photoreceptor cytoplasmic calcium concentration decreases during light-adaptation and this calcium decrease is at least one of the underlying mechanisms of light-adaptation. Recently researchers found novel proteins that regulate the metabolism of cGMP, the second messenger in the phototransduction mechanism By taking these proteins into consideration, one can explain molecular mechanism of photoreceptor light-adaptation.

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Ca²⁺ dependent and Ca²⁺ independent regulation mechanisms of neurotransmitter release at the synapse were reviewed. A Ca²⁺ -chelator, BAPTA, was loaded into the presynapic nerve terminal of the frog neuromuscular junction. Then, among four components of nerve-stimulation induced increases in transmitter release, the fast facilitation was completely eliminated, while the other three slower components: the slow facilitation, augmentation and potentiation, remained unaffected, The fast facilitation was recovered, when the external Ca²⁺ was introduced into the nerve terminal. This is a strong support for the residual Ca²⁺ hypothesis on the fast facilitation and shows that the three slower components occur independently of internal Ca²⁺ concentration. ATP, TNBS, crotoxin, erithrosin B and hypertonicity were also suggested to modulate the release independently of internal Ca²⁺ concentration. Ca²⁺ independent regulation of transmitter release has also been reported on many other synapses, recently.

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The regular spontaneous firing Onchidium neuron shows various discharge patterns depending on the dc polarizing current: regular beating, regular bursting and irregular bursting dischrges. The one-dimensional map of interspike intervals in irregular discharges indicates that fluctuations in interval are not random but deterministic chaos. These auto-active discharges occur due to steady state negative slope conductance in the subthreshold membrane potential region, and complex discharges patterns result from the interaction between spikes and slow membrane potential oscillations due to slow channels. The modeled neuron of Hodgikin and Huxley type replicates the experimental data very well and suggests a route to chaos through a cascade of period-doubling bifurcations. We also discuss importance of discharge patterns for signal transduction in the nervous system.

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The proteasome is a 20S multi-protease complex and consists of a set of small polypeptides with the same evolutionary origin. The 20S proteasome associates reversibly with multiple protein components to form a 26S dumbbell-shaped complex that catalyzes ATP-dependent, selective breakdown of proteins ligated with ubiquitin, suggesting that the 26S complex is a new type of supramolecular, ATP-requiring protease complex in eukaryotic cells. In this review, we summarize the protein and gene structures of proteasomes and discuss the biological function (s) of proteasomes, such as involvement of the ubiquitin pathway, antigen processing/presentation and indispensable role of cell proliferation.

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The utility of stable isotope measures of bioelements as a tool to understand a variety of ecogeochemical interests is discussed. As an example, environmental changes inferred, based on the analysis of natural isotope abundances, from differences in contributions of C₃ and C₄ fixations to bat guano were given.

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