Subcellular Localization of the GABA-Shunt Enzymes in Euglena gracilis Strain Z

SYNOPSIS. Glutamate decarboxylase, γ-aminobutyrate-α-ketoglutarate aminotransferase and NAD-linked and NADP-linked succinic semialdehyde dehydrogenase, all constituting the GABA (γ-aminobutyrate)-shunt pathway of glutamate metabolism are localized in the mitochondrial matrix in a streptomycin-bleached mutant of Euglena gracilis strain Z. Glutamate dehydrogenase, requiring NADP as the cofactor, was distributed in the cytoplasm. An improved version of the controlled digestion method for preparing Euglena mitochondria, which involves use of trypsin and a trypsin inhibitor and removal of broken cells before mechanical disruption of cells, is also described.     

The Fine Structure of Plastids in Various Tissues in the Leaf Blade of Rice

Ultrastructural variations of plastids in a leaf blade of riceare examined by electron microscopy. Plastids are identifiedby their starch-accumulating activity in detached leaves illuminatedfor 48 h. Plastids are observed in all the tissues that containcytoplasm. The structure of plastids varies among differenttissues but is rather uniform within a tissue. Among varioustypes of plastids other than chloroplasts in chloren-chyma,plastids of guard cells, sieve elements, and companion cellsare characteristic of the respective tissues. Ultrastructuralfeatures of vascular bundles and stomata of the leaf blade ofrice are also described.     

Light and Electron Microscope Studies on Synergistic Interaction between Gibbereffic Acid and 4-Ethoxy-1-(p-tolyl)-s-triazine-2,6 (1H, 3H)-dione in Growth of Rice Leaf Sheaths

4-Ethoxy-1-(p-tolyl)-s-triazine-2,6(1H,3H)-dione (TA) dramaticallyand synergistically promoted gibberellic acid-induced elongationof rice second leaf sheaths. The elongation from 84 to 132 hafter sowing occurred only at the region 0–2 mm from thebase in control samples, at the 0–4 mm region in TA- orGA-treated samples, and at the 0–12 mm region in TA plusGA-treated samples. The increase in elongation rate inducedby TA and/or GA was greatest in the 0–2 mm region anddecreased gradually toward the ligule. The longitudinal growthinduced by TA and/or GA was due to the increase in cell numbersby cell division, as well as to increase in length of cells.Electron microscopic examinations revealed that TA and/or GAsuppressed the development of plastids which caused the leafcolour to be pale. Irrespective of TA and/or GA treatment(s),microtubules were observed to be exclusively oriented perpendicularto the longitudinal axis of the cell in actively elongatingzones, and in fully elongated zones they were randomly oriented.     

INHIBITION OF LAMINA INCLINATION BY CYTOKININ IN EXCISED RICE LEAVES

Effects of kinetin and other purine and pyrimidine derivativeson lamina inclination in excised rice leaves have been examinedin this work. Kinetin inhibited the lamina inclination both in the presenceand in the absence of added IAA, and was effective even at 10^–7M. The decreasing order of inhibitory activities of kinetinand its analogs was as follows; 6-benzylaminopurine, kinetin,2-amino-6-furfurylaminopurine (2-aminokinetin), 2-amino-6-benzylaminopurine,kinetin-9-glucoside, 6-benzylaminopurine-9-glucoside. Otherpurine derivatives, 8-azaadenine, 2, 6-diaminopurine and 8-azaguanine,and colchicine also inhibited the lamina inclination. The inhibitiveaction of kinetin was not reversed by the addition of adenine,hypoxanthine, uracil and thymine. (Received May 20, 1965; )     

Ganglioside Expression in Melanomas From Japanese Individuals: Unusual Pattern in Two Patients With Metastatic Lesions of Acral Lentiginous Melanomas

Melanoma among Japanese is rare, and differs in its clinical and histological characteristics from that found in Caucasians. In this study, the ganglioside expression of melanoma specimens obtained from Japanese was determined and compared with previously published data on Caucasians. The ganglioside composition of 25 biopsy melanoma specimens, including 13 primary and 12 metastatic lesions, was studied using thin layer chromatography. Four gangliosides (G_M3, G_D3, G_M2, G_D2) were most commonly expressed in melanomas in Japanese. The expression of gangliosides was quite variable in both primary and metastatic melanomas as seen in previous reports. No significant differences were observed between gangliosides from primary and metastatic sites. A new type of ganglioside expression, in which G_M3 was nearly the only ganglioside (>95%), was found in metastatic tumors from two Japanese patients with acral lentiginous melanoma (ALM), which is the most common clinical and histopathological type of melanoma among Japanese but is very unusual among Caucasians. The patterns of expression were similar to those in Caucasians except for the detection of a “new” pattern.