摘要:

SUMMARYCytoplasmic connections between cells of a coenobium inGonium pectoralehave been investigated. Light‐microscope observations have been supplemented with stains considered specific for plasmodesmata.Darkfield illumination, polarized light, and phase‐contrast microscopy have also been employed. Comparative studies ofVolvox aureus(with thin cytoplasmic strands) andV. globator(with thick strands) have been made. No plasmodesmata have been demonstrated inG. pectorale;however, the cells are connected to one another by individual, almost transparent cytoplasmic connections, possibly the membrane. In older coenobia the cells become separated; the membrane connections stretch ultimately appearing as fine threads between the ce

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04547.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYGrowth ofAnacystis nidulansin wavelengths of light predominantly absorbed by chlorophyll a causes dramatic lowering of the chlorophyll content with only small changes in phycocyanin and carotenoids. Steady‐state growth under red photographic safe lamps produces cells with 1/4 of the chlorophyll content of cells grown under low intensities of white (tungsten) illumination. Pigment analyses permit resolution of in vivo absorption spectra into spectra of the component pigments and also the fractional absorption vs wavelenth. Even in normally pigmented cells phycocyanin is the major collector of light quanta for photosynthesis. The observed pigment control is viewed as a special case of intensity control which has chromatic character by virtue of the presence of two different pigment systems linked to the two light reactions of photosynthesi

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04548.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYMotility was observed inScenedesmus dimorphus, S. obliquus,andCoelastrum microporumincubated at IS C in a medium lacking a nitrogen source. Flagellated cells of the WH50strain ofS. obliquuscould not be cultured in a variety of organic media. From this and the occasional occurrence of quadriflagellated cells inC. microporum, ifappears possible that the motile cells are gametes.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04549.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYInability of single cells of coccoid blue‐green algae to form visible colonies on an agar medium has long been a puzzle, especially in view of the high growth rates characterizing coccoid blue‐green algae as a group. WithAnacystis nidulansgrowing on a medium containing citrate as chelating agent, single cells never grew unless catalase was added at time of plating. On a very similar medium but containing EDTA as chelator, single cells ofAnacystisproduced visible colonies.With two other coccoids, both marine isolates, on an EDTA medium (ASP‐2), reasonably quantitative colony counts were obtained. The data are interpreted as a lethal peroxide formation by single cells in light and air by an, as yet, unspecified pathway. Detoxification or reversal of the lethality of small amounts of peroxide, cellularly produced, presumably by the EDTA in the medium, suggests a new role for EDTA in algal media. The data present an insight into the reason (s) for the anaerobic or microaerophilic character of blue–green algae so often observed in

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04550.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYChlorella pyrenoidosaChick, van Niel's strain, grown in a chemically defined medium, in which the potassium was replaced with rubidium, attained only20%of the growth rate of algae in media containing K. Addition of sodium to K‐deficient media spared Rb uptake. Neither growth nor uptake of Rb were accelerated when glucose was added to media Cells which had been maintained on K‐free media, did not immediately respond to K, indicating that their metabolism had become adjusted to Rb.Free and combined amino acids, nonketo organic acids, polysaccharides, and chlorophylls were similar in K or Rb media. Fewer porphyrins, and in smaller quantity, were found in the cells grown in Rb media.Cells grown in K‐free media, analyzed by X‐ray fluorescence, showed0.039%of their dry weight to be K contamination. When the K equivalent to the small contamination of the Rb salt was added to a Rb‐free medium, the cells failed to grow. The data indicate that Rb either can replace K entirely in cell metabolism, or that it can spare the K requirement. Substitution of K by Rb does not permit normal growth if rate is the

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04551.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYTrichosarcina polymorphagen. et sp. nov. is newly described as a member of the Ulvales, Schizo‐meridaceae. The life cycle includes a uniseriate, Hormidiuzn‐like phase; a pluriseriate stage, and, finally, a chain of sarcinoidpackets which may dissociate. The cells are uninucleate, with a parietal cbloroplast and single pyrenoid. Quadriflagellate zoospores are produced singly by cells of the pluriseriate and sarcinoid stages. Sexual reproduction was not obser

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04552.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1965.tb04553.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY