Estimation of tyrosine-40-DNA distance in the filamentous phage Pf1 by analysis of its intrinsic fluorescence properties

Iodination of the exposed Tyr-25 in the coat protein decreases the fluorescence intensity of the filamentous phage Pf1 to less than 3% of its original fluorescence. If one assumes that the total residual fluorescence originates from the non-iodinated, buried Tyr-40, one can estimate the distance between Tyr-40 and the DNA bases in Pf1 to be less than 7 A, making use of the Foerster law for fluorescence energy transfer. The result is consistent with the idea that Tyr-40-DNA interaction is responsible for the unusually large axial base separation in Pf1-DNA.     

Wingea,a new genus of the Saccharomycetaceae

The yeast species previously described asPichia robertsii v. d. Walt has been transferred to the new genusWingea. The diagnosis for the genus is given.     

Preferential expression of cellular retinoic acid binding protein in a subpopulation of neural cells in the developing mouse embryo

The cellular retinoic acid binding protein is thought to be involved in the retinoic-acid-mediated signal transduction pathway. We have isolated the mouse cellular retinoic acid binding protein cDNA from an embryonal-carcinoma-derived cell line by using differential cDNA cloning strategies. In situ hybridization on sections of mouse embryos of various developmental stages indicated that the cellular retinoic acid binding protein gene, which we localized on mouse chromosome 9, is preferentially expressed in a subpopulation of neurectodermal cells. This restricted expression pattern suggests an important role for cellular retinoic acid binding protein in murine neurogenesis.     

Territorial behaviour in southern impala rams (Aepyceros melampus Lichtenstein)

The role of territoriality was investigated by studying 25 impala rams at a reserve in the Waterberg region of South Africa (23°45′S, 28°23′E). Mean territorial tenure was 67.25 days (range 23–99), with a mean territory size of 21.0 ± 11.27 ha, compared with home ranges of 34.1 ± 9.03 ha for territorial rams and 58.8 ± 33.35 ha for bachelor rams, using the fixed kernel method. Territory boundaries remained constant, whilst the area surrounding important features such as water holes, appears to be neutral in terms of territoriality. The rut, as evidenced from peaks in chasing and roaring, lasted for 2 months from 10 April to 10 June 2001, with intensified behaviour including matings observed from 16 May to 4 June 2001. Territorial rams chase and roar more than bachelors. Flehmen and display behaviours are performed by all rams, whilst fights and other reproductive behaviours are generally rare. Bachelors browse more than territorial rams. Only bachelors spar and allogroom, and orally groom themselves more than territorial rams.