Recent progress in cryobiology and studies on the physical properties of water in biological systems at low temperatures are reviewed. The response of living cells to ice formation and the mechanism of cellular injuries occurred during both freezing and thawing processes are discussed. The survival of living cells strongly depends upon cooling and warming rates of specimens, water permeability of membranes and thermal behaviors of cell water.
Calorimetric measurements of enthalpy changes of water in microbial cells during freezing and thawing processes are expected to reveal some information about the low temperature characteristics of microbes with special reference to physical states of the cell water.

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The conception of "electrogenic ion pump", actively separating charges across cell membranes, has been recently developed as a concequence of the recognition of the more intimate relationship between the mechanism generating resting membrane potential and the energy metabolism of the cell than formerly supposed. Existence of the resting potential larger than the equilibrium potential of any major permeable ion across cell membrance supports the above view and is regarded as a safety criterion for electrogenic activity. Another criterion, rapidity of the depolarization caused by the application of inhibitory reagents or conditions for energy metabolism, is examined critically taking several experimental results for instances. The investigations towards the energy sources for electrogenic activity and several hypothetical models for electrogenic ion pump are also reviewed. The ion which is transported across membrane by the electhogenic mechanism seems to be H⁺ in most plant cells, though in some cases Cl^- is a possible candidate. The role of H⁺ in plant cells as a substitute of Na⁺ in the case of animal cells is reviewed with special reference to the "co-transport" of organic molecules and also from the view point of origin and evolution of the membrane transport systems.

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In the last decade, SQUID "Superconducting Quantum Interference Device" has been developed in low temperature physics area. The SQUID is a device to which quantum effect in superconductivity is applied, and is used as a high sensitive magnetometer, low level current detector etc.. In this report, basic concepts and applications of this device are reviewed, and then our development on this device for biological measurements is presented. Possibilities of kinetic measurements of some reaction systems are also discussed.

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In an electric and a magnetic field rod-like molecular clusters were formed in liquid crystalline solutions of polypeptides, and oriented in the field directionowing to their permanent and induced dipole moments, respectively. Each molecular cluster had a length of several microns and a diameter of about 0.1 micron, and composed of some 5×10⁵ polymer molecules in a methylene bromide solution of poly-γ-benzyl-L-glutamate of degree of polymerization 650. Polymer molecules oriented parallel to the cluster axis, but their ordering fluctuated statistically. There existed some differences among the systems of the liquid crystalline solutions tested

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