Abstract: The isomerization of horse-heart ferricytochrome c caused by varying pH was kinetically studied by using circular dichroism (CD) and optical absorption stopped-flow techniques. In the pH range of 7--13, the existence of the three different forms of ferricytochrome c (pH less than 10, pH 10--12, and pH greater than 12) was indicated from the statistical difference CD spectra. On the basis of analyses of the stopped-flow traces in the near-ultraviolet and Soret wavelength regions, the isomerization of ferricytochrome c from neutral form to the above three alkaline forms was interpreted as follows (1) below pH 10, the replacement of the intrinsic ligand of methionine residue by lysine residue occurs; (2) between pH 10 and 12, the uncoupling of the polypeptide chain from close proximity of the heme group occurs first, followed by the interconversion of the intrinsic ligands; and (3) above pH 12, hydroxide form of ferricytochrome c is formed, though the replacement of the intrinsic ligand by extrinsic ligands may occur via different routes from those below pH 12. The CD changes at 288 nm and in the Soret region caused by the pH-jump (down) from pH 6.0 to 1.6 were compared with the appearance of the 620-nm absorption band ascribed to the formation of the high-spin form of ferricytochrome c. Both CD and absorption changes indicated that the isomerization at pH 1.6 consisted of two processes: one proceeded within the dead-time (about 2 ms) of the stopped-flow apparatus and the other proceeded at a determinable rate with the apparatus. On the basis of these results, the isomerization of ferricytochrome c at pH 1.6 was explained as follows: (1) the transition from the low-spin form to the high-spin forms occurs within about 2 ms, the dead-time of the stopped-flow apparatus; and (2) the polypeptide chain is unfolded after the formation of the high-spin form.

Abstract: The paper examines systematic relationships among primates between brain size (relative to body size) and differences in ecology and social system. Marked differences in relative brain size exist between families. These are correlated with inter-family differences in body size and home range size. Variation in comparative brain size within families is related to diet (folivores have comparatively smaller brains than frugivores), home range size and possibly also to breeding system. The adaptive significance of these relationships is discussed.

Abstract: The behaviour of a free-living group of male red deer (Cervus elaphus L.) on the Isle of Rhum, Scotland, was studied throughout the year to investigate the relations between social dominance and food access. The study is based on the collection of agonistic interactions between members of the study group outside the rutting season. Analysis of these confirmed that dyadic dominance relationships summate to a very clear agonistic hierarchy, while seasonal changes in frequency and type of interactions suggested that rank in the hierarchy may affect access to food through direct feeding interference. This would constitute a selective advantage of the acquisition of high rank. A behaviour pattern in which a stag displaces a subordinate and takes over his feeding-site is proposed as a mechanism of direct feeding interference. It occurs throughout the year, but with a frequency closely related to changes in food availability and quality. The proportion of such interactions that an individual wins is related to his rank, so advantages gained from this behaviour would primarily benefit high-ranking stags. These are likely to consist of improved body condition and winter survival. The importance of high rank in obtaining access to limited food was supported by the results of a simple experiment providing a small area of fertilized grass. Most of the grazing in the area was due to the highest-ranking stag present at any time.