Agar fractions could protect apple shoots cultured in liquid media against hyperhydricity

Apple shoots were grown in a Murashige and Skoog liquid proliferation medium containing 4.4 10 -6 M BA, and supplemented with various fractions of agar. Hydrolysed agar from Difco was able to overcome hyperhydricity when its concentration was increased to 0.7%. Among the fractions isolated from this hydrolysed agar, only oligosaccharides were found to reduce the occurrence of this developmental abnormality. The most anti-hyperhydric fraction had a molecular weight slightly less than 1900 daltons and contained methylated and sulphated galactose derivatives. This revised version was published online in June 2006 with corrections to the Cover Date.     

A protein of Mr 80,000 is associated with the nucleolus organizer of human cell lines

A rabbit serum which had previously been reported to have an immunological affinity for centrosomes of human cell lines was shown also to be specific for the nucleus. Optical and ultrastructural immunolocalization in HeLa cells showed that this specificity is restricted to the fibrillar centre of nucleoli either in untreated or actinomycin D treated interphase cells. In mitotic cells discrete labelling was observed on chromosomes and shown to correspond, on spread metaphase plates, to the short arms of acrocentric chromosomes, i.e. to the nucleolar organizer regions (NORs). Using independent cell fractionation procedures in the human T-lymphoblastic KE 37 cell line and purification of immunoglobulins by affinity to antigens detected by electrophoresis and blotting, a strict correlation between immunoreactive proteins and cytological staining was established. The nucleolar specificity was shown to correspond to a protein with an M_r of 80,000 while the centrosomal specificity corresponded principally to a protein doublet of 60,000–65,000. These antigens share common epitopes as shown by the staining of both NOR and centrosome by immunoglobulins purified by affinity to either type of protein.     

Photostimulation of Hydroxypyruvate Reductase Activity in Peroxisomes of Pharbitis nil Seedlings: I. Action Spectrum

Hydroxypyruvate reductase activity in etiolated cotyledons ofPharbitis nil is highly stimulated by white light. The actionspectrum shows three effective regions: blue, red and far red.The main characteristics of this high irradiance reaction responseis a high blue efficiency and a low red efficiency. Experimentswith herbicide-treated plants demonstrated that chlorophyllis not involved in the regulation but suggest that a specificblue-absorbing pigment is involved, in addition to phytochrome. (Received November 22, 1983; Accepted June 20, 1984)