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; )     

AN f-TYPE CYTOCHROME FROM CHLORELLA VULGARIS

A method for isolating an f-type cytochrome (Chlorella cytochrome554) from Chlorella vulgaris var. viridis (CHODAT) utilizingN, N-diethylaminoethylcellulose is described. The spectrum ofreduced Chlorella cyt. 554 has absorption maxima at 554 mµ(-band), 524 mµ (ß-band), 417 mµ (SORETband), 352 mµ, 319 mµ and 277 mµ (proteinband). The oxidized form has absorption maxima at 554mµ530 mµ, (ß-band), 412 mµ (SORET band),360mµ 322 mµ and 275 mµ (protein band). Thespectral characteristics resembled other f-type cytochromes,e. g. in the high SORET to -extinction ratio (6.8) and an asymmetric-absorption band (especially at liquid N₂ temperature) ; butcharacteristic differences were present. Mitochondria from whitelupine seedlings and sweet potato roots reduced Chlorella cyt.554. From the effects of antimycin A and 2-heptyl-4-hydroxyquinolineN-oxide it appears that Chlorella cyt. 554 was reduced sequentiallybefore cytochrome a+a₃ and near the level of the cytochromesof the b type. Oxidation was slow using lupine mitochondriaand nil with sweet potato mitochondria. The oxidation-reductionpotential at pH 7.2 and 30? was 0.35 V. Ascorbate, cysteine,glutathione and Na₂S₂O₄ readily reduced Chlorella cyt. 554.The cytochrome was not autoxidizable and was slowly oxidizedby excess potassium ferricyanide. The reduced form did not reactwith CO and was not adsorbed by IRC-50 or Cellex-P cation exchangers. ¹ Temporary address until September 1961: Department of HorticulturalScience, University of California, Los Angeles 24, California,U. S. A. ² Present address: Plant Industry Station, Pioneering ResearchLaboratory, Marketing Quality Research Division, AgriculturalMarketing Service, Beltsville, Maryland, U. S. A. (Received January 16, 1961; )     

A CHLORELLA MUTANT LACKING NITRATE REDUCTASE

Shafer , John , Jr ., James E. Baker and John F. Thompson . (U. S. Plant, Soil and Nutrition Laboratory, U. S. D. A., Ithaca, New York.) A Chlorella mutant lacking nitrate reductase. Amer. Jour. Bot. 48(10): 896–899. 1961.—Following ultraviolet irradiation of Chlorella pyrenoidosa, a mutant was isolated which could not utilize nitrate nitrogen but which could use nitrite, ammonia and some organic nitrogen compounds. This suggested an abnormal nitrate reductase system. Nitrate reductase activity was found in cell-free extracts of wild-type cells but not in similar preparations from the mutant. A test for inhibitor in the mutant extract showed that there was none. Therefore, it was concluded that the mutant lacks an active nitrate reductase.     

EFFECT OF ATRAZINE ON CHLORELLA VULGARIS

Samples of a synchronous culture of Chlorella vulgaris were treated with: (a) atrazine, (b) atrazine + glucose, or (c) glucose. Cultures were sampled 0, 24, 48, and 72 hr, after treatment. Chlorophyll and packed cell volume were determined on each, and electron micrographs were taken. Atrazine prevented normal increase in packed cell volume and chlorophyll; this cessation of growth was counteracted by glucose. Chlorella utilized both the endogenous products of photosynthesis and an exogenous energy source, glucose in this instance, simultaneously. The atrazine-treated cells did not contain starch; control cells, atrazine-glucose- and glucose-treated cells did. Atrazine did not cause any observable abnormalities in cell organelles.     

小球藻病毒的分离

真核藻类作为一类重要的淡水和海洋水生生物与人类和环境有密切关系。在生态学上,藻类作为普通食物链中的原初生产者,在水环境中显得尤为重要,可作为许多水生生物的食物,也可使水域在一定范围内自净。藻类还极有希望成为人类新的食物来源和能源。但藻类的过量繁殖可引起严重的水污染。因此,搞清真核藻类与其寄生物—真核藻类病毒的关系,对维持藻类的生态平衡,控制利用藻类资源意义重大。对真核藻类病毒的深入研究已揭示出这类病毒在自然界的广泛存在。到目前为止,已报道发现的真核藻类病毒或病毒状颗粒(Virus—like particle)至少有44种,但多数仅限于电镜观察。直到病毒裂解性小球藻的发现,才使得对真核藻类病毒的研究提高到一个新水平,也使该领域的研究越来越受到人们的关注,国际上已开展真核藻类病毒研究的国家有美国、日本,德国等,我国在该领域的研究尚属空白。在国内开展真核藻类病毒的研究,首先要深入地调查我国的真核藻类病毒资源,同时可阐明一类新的病毒——寄主关系的分子生物学基础,了解诸如病毒基因组在寄主细胞中的表达调控,为研究高等植物基因的表达调控提供一个适宜的模型。另外,由于已知的真核藻类病毒具有相当大的基因组,可预见其基因…     

NEW ARGININE-CONTAINING PEPTIDES ISOLATED FROM CHLORELLA CELLS

Seven kinds of arginine-containing peptides were isolated fromthe cells of Chlorella ellipsoidea, and their structures wereinvestigated. Their amino acid make-ups and quantities presentin randomly grown algal cells were found to be as follows (indecreasing order of contentin moles per dry weight of cells): Arg-Arg, Arg-Arg-Glu, Arg-Arg-Arg, Arg-Glu> Arg-(Arg₂, Glu)-Glu>Arg-(Arg₃,Glu), Arg-(Glu, Asp) Using synchronously mass-cultured algal cells, the quantitiesof these peptides as they changed during the algal life cyclewere followed. It was found that, except in the case of Arg-Arg-Arg,the contents (in moles per dry weight of cells) of the peptides(i) markedly increased during the stages from D_n to L₁, (ii)remained almost constant or more or less appreciably increasedduring the stages from L₁ to L₃, and (iii) decreased sharplyduring the transformation of L₃-cells (via L₄) into D_n-cellsin the dark. The content of Arg-Arg-Arg remained almost constantduring the period from D_n to L₃, and on transference of L₃-cellsin the dark it increased temporarily and then decreased duringthe transformation of L₄-cells into D_n-cells. Significance andpossible roles of these peculiar peptides in the life cycleof Chlorella were discussed. (Received May 10, 1965; )     

TEMPERATURE CHARACTERISTICS FOR THE METABOLISM OF CHLORELLA : III. THE CATALYTIC DECOMPOSITION OF HYDROGEN PEROXIDE BY CHLORELLA PYRENOIDOSA

The decomposition of hydrogen peroxide by intact Chlorella cells follows a first order course at very low temperatures, but at higher temperatures gives falling first order constants. Between 0.6° and 20°C. the value of µ is 10,500 calories.     

CHROMATOGRAPHIC ANALYSES OF ACID-SOLUBLE POLYPHOSPHATES IN CHLORELLA CELLS

Using uniformly ³²P-labeled Chlorella cells as material, compositionof acid-soluble inorganic polyphosphates was studied by paperchromatography and ion-exchange chromatography. 2.By the paper chromatographic analysis it was found that theacid-soluble polyphosphates consisted of highly condensed polyphosphates.Ring-forming tri- and tetrametaphosphates, pyrophosphate andtripolyphosphate were not detected in the acid-soluble fractionof the algal cells. 3.By an ion-exchange chromatography with the use of increasingconcentrations of KCl-solution as eluant, it was found thatthe acid-soluble polyphosphate was a mixture of polyphosphateswith a variety of condensation number (n-values). Polyphosphatesof the n-values between 3 and 15 were only 20% of the totalacid-soluble polyphosphate. The majority of the other polyphospateshad greater n-values which was eluted with 0.5–1.0 M KCl. (Received March 2, 1964; )     

IDENTIFICATION OF CHLORELLA STRAINS BY SEROLOGICAL TECHNIQUES1,2

Three strains of Chlorella were examined, by serological procedures for cellular antigenic differences. Antibodies produced in rabbits against, the 3 different Chlorella strains demonstrated the presence of antigens common to all 3 strains. Adsorbed antisera identified antigens specific for each, strain.     

QUANTITATIVE SEPARATION OF INORGANIC POLYPHOSPHATES IN CHLORELLA CELLS

Using unicellular green alga, Chlorella ellipsoidea, which hadbeen labeled with ³²P-phosphate, re-examination was performedon our routine method for the quantitative separation of inorganicpolyphosphates (poly-Pi). Confirming the previous results, itwas demonstrated that poly-Pi's in Chlorella cells are clearlyseparated from each other by successive extractions with cold8% TCA (poly-Pi "A"), with cold KOH at pH 9 (poly-Pi "B"), andwith 2 N KOH (poly-Pi's "C" and "D"; the former precipitateson neutralization with PCA, leaving the latter in solution).Use of 2N KOH was found to be most suitable for the purposeof fractionation of poly-Pi's "C" and "D." (Received February 25, 1965; )