SYNCHRONOUS MASS-CULTURE OF CHLORELLA

A new culture apparatus was constructed to obtain large quantitiesof synchronized cells of Chlorella ellipsoidea. Two flat culturechambers made of lucid acrylate resin (each 20 liters in capacity)were placed in a water thermostat together with a bank of 17daylight fluorescent lamps, and the culture was run by the methodstarting from a homogeneous population of D_s-cells accordingto TAMIYA et al. It was demonstrated that with this apparatusone can obtain as much as 200–400 mg (dry weight) eachof algal material at 8 or 9 different stages in one cell cycle.Completely synchronized cell cycles could be repeated as manyas 10 times in one series of experiment, indicating that theapparatus can produce 2–4g (dry weight) each of algalcells of different developmental stages. (Received April 2, 1964; )     

Polysome formation in Pinus resinosa at initiation of seed germination

Ribonucleic acid systems present in dormant embryos of red pine(Pinus resinosa Ait.) were studied. Sucrose gradient centrifugationwas used to isolate ribosomes of dormant embryos and embryosimbibed for various times in the light. In dormant embryos,ribosomes existed as monomers. After imbibition, a gradual decreasein the monomers was observed, with subunits and polymers ofribosomes detected within 4 hr. When poly U was added to homogenatesof dormant embryos, formation of polysomes was observed aftera 15-min incubation at 25°C. However, artificial polysomeformation required some factors from heavy particles in thehomogenates. ¹ Contribution from the Missouri Agricultural Experiment Station,Journal Series No. 7079. ² Present address: Government Forest Experiment Station, Meguro,Tokyo, Japan. (Received April 20, 1971; )     

A systematic revision of Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions

IKEDA, H. & OHBA, H., 1993. A systematic revision of Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions . Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions are revised. Potentilla festiva Soják, P. josephiana H. Ikeda & H. Ohba, P. lineata Trev., P. fallens Card, and P. polyphylla Wall, ex Lehm. are recognized. Potentilla josephiana is a new name for P.fulgens Wall, ex Hook. var. intermedia Hook. f. Four varieties are recognized in P. polyphylla: var. polyphylla; var. himalaka H. Ikeda & H. Ohba, var. nov.; var. interrupta (Yü & Li) H. Ikeda & H. Ohba, stat. & comb, nov.; and var. barbata Lehm. A polyploid series is found in this group. Four putative hybrids between the species are also recognized.     

The Effect of Benzyladenine on Changes in Nuclease and Protease Activities in Intact Bean Leaves during Ageing

Primary leaves of intact bean plants (Phaseolus vulgaris L.) were treated with benzyladenine (BA) at different stages during growth. Changes in DNase, RNase, and proteas activities in the leaves were followed. Unlike the case of various excised tissues, cytokinin raised the activities of these hydrolases in intact bean leaves. Because BA elevated the levels of DNA, RNA, and protein in intact leaves, it may stimulate both synthesis and decomposition of these cellular constituents. The hydrolase activities showed differential responses to BA according to the age at which the leaf received the hormone treatment.     

INSTABILITY OF MESSENGER AND RIBOSOMAL RNA IN A GLUE-PROTEIN MUTANT OF Bombyx mori

The mucous glands of Bombyx pupae secrete glue proteins which attach deposited eggs to the mounting sheet. A mutant of a dominant gene, named no glue (Ng) , produces nonadhesive eggs which have a low capacity for glue-protein synthesis. In the present study it was shown that the mucous glands of Ng silkworms showed rapid degradation of mRNA as well as rRNA during development; this may cause the low capacity for glue-protein synthesis in the mutant organ. In contrast, the mucous glands of normal silkworms showed a significant increase in content of RNA's until the maximum rate of glue-protein synthesis was achieved. The degradation of RNA in the Ng mucous gland was inhibited by actinomycin D injected into the body fluid. Thus it is supposed that the Ng gene codes for a presumptive controller RNA, which would be the mediator of RNA instability in the mucous glands of Ng pupae.     

Self or Non--self Recognition in Compound Ascidians

SYNOPSIS. Certain species of compound ascidians have an abilityto distinguish self colonies from non—self colonies withinthe same species. This ability, called colony specificity, ismanifested by the fusibility between colonies. The fusibilityamong colonies of Japanese Botryllus is genetically controlledby a series of multiple alleles at a single locus. The fusibilityis determined by a factor(s) in blood, so that the fusibilitycan be altered by the exchange of blood. It is suggested thatrejection, called "nonfusion" reaction, may occur from the interactionbetween blood cells and blood humoral factor(s).