Quinone and pheophytin in the photosynthetic reaction center II from spinach chloroplasts

Prenylquinones and pheophytin a in a preparation of photosynthetic reaction center II from spinach chloroplasts were chemically determined. Each reaction center II had two molecules, each of plastoquinone-9 and pheophytin a, but practically no phylloquinone, α-tocopherylquinone or α-tocopherol.     

Mechanism of activation and spectral shift of the F-695 emission band in chloroplasts as induced by 1,10-phenanthroline

1. Changes in the fluorescence emission spectrum of chloroplast, at 77 °K, induced by chaotropic reagents and 1,10-phenanthroline, were analyzed.2. Fourth-derivative analysis of the emission spectra identified the exact location of a new band (referred to as “F-700”) at 700 nm and showed that the conversion of F-695 into F-700 does not occur by a gradual red-shift of the F-695 band, but by the appearance of a new band at 700 nm at the expense of an intensity decrease in the F-695 emission.3. F-700 shows two distinct fluorescence characteristics, namely the wavelength of its emission maximum and its intensity, but still retains the principal properties of F-695 such as steep temperature dependence at low temperatures, transient phenomena at 77 °K, and an excitation spectrum of the Photosystem II type. Thus F-700 is concluded to be a modified state of F-695.4. In addition to the compounds of the urea-guanidine class, inorganic anions such as SCN^?, I^? and ClO₄^? were active in the transformation. The specificity and theorder of effectiveness of these reagents indicated that their action is that of chaotropic reagents. Transformation was inhibited by the presence of compounds such as sugars, salts, alcohols and dimethylsulfoxide which seem to affect the activity of water.5. 5-Methyl-1,10-phenanthroline partly substituted for the action of 1,10-phenanthroline, while the other six different derivatives of 1,10-phenanthroline and a few other bifunctional ligands were inactive. The structure-activity relations and the effective concentrations in the transformation differed greatly from those of the inhibition of the electron transport chain, suggesting that the action of 1,10-phenanthroline in the transformation is a yet unrecognized action of this reagent on Photosystem II.6. Transformation was generally observed in chloroplast preparations from 11 different higher plants and two species of algae tested. In Lolium sp. the transformation was partly attained by 1,10-phenanthroline alone.7. From these results, the state of F-695 in chloroplast membranes and the mechanism of transformation into F-700 are discussed.     

Cytogenetical survey of black rats,Rattus rattus,in southwest and Central Asia,with special regard to the evolutional relationship between three geographical types

A chromosome survey of the black rat, Rattus rattus, was made from animals collected at different localities in Southwest and Central Asia. Asian type black rats (2 n=42) were distributed in northern India, northern Pakistan, while the Oceanian type rats (2 n=38) were found in southern India, southern Pakistan and Central Asia. A border line of distribution of rats with Asian and Oceanian types can be drawn dividing India and Pakistan into northern and southern parts. A hybrid type between Asian and Oceanian types was found in Karachi, Pakistan. Rats with 40 chromosomes, probably a transient type from Asian to Oceanian type, were found in Sri Lanka (Ceylon). It is suggested that these three geographic variants have developed via sequential events of Robertsonian fusion of acrocentric chromosomes in Asian type black rats. This fusion probably took place somewhere in southern India. The Oceanian type black rats that thus developed in southern India migrated widely to the rest of the world through Central Asia and Europe accompanying the movement of mankind.     

Characterization of a 47-Kilodalton Chlorophyll-Binding Polypeptide (CP-47) Isolated from a Photosystem II Core Complex

The purified photosystem II core complex from spinach with aparticle size of about 480 kDa and containing five constituentpolypeptides was further resolved by octyl-rß-D-glucopyranosidetreatment followed by separation by high-performance liquidchromatography using a gel-permeation column. Of the four clearlyseparated, chlorophyll-containing fractions, one with a particlesize of 170–180 kDa was composed entirely of a single,47-kDa polypeptide. This chlorophyll a-polypeptide containsrß-carotene and pheophytin a, but no plastoquinone.The number of chlorophyll a associated with this polypeptidein situ was estimated to be 6–7 and an oligomeric structureof this polypeptide in vivo was proposed on the basis of itschlorophyll/protein ratio and the isolated particle size. Thecomplex exhibited F-695 emission, but was photochemically inactive.The amino acid composition of the apoprotein was also determined. (Received March 12, 1984; Accepted June 7, 1984)     

Frequency of chromosome polymorphism in Rattus rattus collected in Japan

This paper deals with a population survey of chromosome polymorphism of Rattus rattus collected in Japan and the results of their test crosses. All the animals had diploid 42 chromosomes, but three chromosome pairs, Nos. 1, 9 and 13, were polymorphic in respect to acro- and subtelocentric chromosomes. Frequency of No. 1 chromosome polymorphism in 453 rats collected in 19 localities showed 343 rats (75.5%) with acrocentric homomorphic pair (A/A), 90 (19.9%) with aerocentric and subtelocentric heteromorphic pair (A/S) and the remaining 20 (4.4%) with subtelocentric homomorphic pair (S/S). All animals collected in northern and northwestern Japan showed only the A/A pair, while those collected in southern and southeastern Japan showed A/A, A/S and S/S polymorphism. The latter group was also classified into 3 populations (east, southeast and south) by the different frequency of the subtelocentric chromosome. Progeny tests revealed that segregation of A/A, A/S and S/S types from F₁ hybrids between various chromosome combinations was not significantly different from the theoretical one. However, the number of animals with A/S pair was always slightly higher than the other two types, while those with S/S pair slightly fewer. Local differences of the chromosome polymorphism in Japan were considered due to the result of migration and selection of the rats with S/S chromosome type.Contribution No. 817 from the National Institute of Genetics, Japan. Supported in part by a grant-in-aid from the Ministry of Education of Japan (Scientific Expedition in 1968, and No. 8801 in 1969).