摘要:

SUMMARYMarine Vaucheriae of North Carolina were investigated in the field and in culture for 4 years. Of the 11 species collected, 4 are new records for North Carolina and 2 are previously unreported species. A new section is established, Acrandrae, to containVaucheria acrandrasp. nov. andVaucheria adelasp. nov. The diagnostic character of the new section is the production of androphores directly from the terminal portion of the main filament rather than from a special cell produced laterally on the filament as in the section Androphorae.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02729.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B12concentrations in the media. In batch cultures, the vitamin B12half‐saturation constants and standard errors were 0.39 ± 0.042 μμg/ml forThalassiosira pseudonana(clone 3H), 1.69 ± 0.24 μμg/ml forIsochrysis galbana,and 2.77 ± 1.65 μμg/ml forMonochrysis lutheri.A chemostat was used to growT. pseudonanawith vitamin B12as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 104cells/μμg vitamin B12, was the same as in the batch culture, 126 ± 13 ± 104cells/μμg. The chemostat half‐saturation constant, 0.26 ± 0.068 μμg/ml vitamin B12, and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B12concentration on growth rates may be complicated by low concentrations of other nutrients or the

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02730.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe snow algaTrachelomonas koliiis transferred from the Euglenophyta (Euglenales) to the Chlorophyta (Volvocales) asChlainomonas koliicomb. nov. As a result of critical examination of both living and type material, this species was found to have 4 flagella per vegetative cell, true starch, and 1 axial plastid per cell with several peripheral lobes. Vegetative cells ofTrachelomonas koliiwere described originally as having 1 flagellum, lacking true starch but having paramylum, and as having several parietal plastids per cell. The reticulate markings on the outer envelope of vegetative cells were found to be different from those in the original illustrations.Vegetative cells and resting spores ofChlainomonas koliiandChlainomonas rubraare compared. The similarities of resting spores ofChlainomonas koliiandChlamydomonas nivalisare discussed. These are the first records ofChlainomonas koliifrom snow in Washington State.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02731.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYOchromonas danicaPrings., a chrysomonad alga which demonstrates a high degree of nutritional versatility, is capable of feeding on the toxic blue‐green algaMicrocystis aeruginosaKuetz. In this paper light microscopic, electron microscopic, and cytochemical examinations of endocytosis inO. danicaare reported, with particular emphasis on the vicissitudes of endocytic and lysosomal activities during intra‐cellular digestion. An interpretation of the function of organelles associated with endocytosis is presen

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02732.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYAlthough domination of 1 species in an algal community has often been attributed to toxic effects, nutrient exhaustion can also lead to competitive exclusion among algal species.The bacteria‐associated blue‐green algaeMicrocystis aeruginosa, Nostoc muscorum,andPhormidium foveolarumwere cultivated in Zehnder‐Gorham's medium No. 11 individually and in their combinations. The growth rates ofMicrocystisand ofNostocwere reduced by the presence of Phormidium. This detrimental effect was apparently not due to formation of any toxic or allelopathic matter. It was caused by the reduction of iron and trace metal concentrations in the medium byPhormidiumto levels too low for normal growth ofMicrocystisandNostoc.Work with the axenic forms of the 3 algal species also indicated a lowering of iron and trace element concentrations byPhormidiumto levels not sufficient for sustained growth ofMicrocystis and Nostoc.Thus, bacteria played no significant role in this example of competitive excl

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02733.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYDetails of structure and reproduction, particularly pre‐ and postfertilization development, are given for the first time inPseudogloiophloea halliae.In general, the author's observations agree with what is known for most species of the genus. Some remarks on the identity of 3 species ofPseudogloiophloeain the tropical and subtropical American Atlantic shores are also include

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02734.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYCell division inChlamydomonas moewusiiis described. The cells become immobile with flagellar abscission prior to mitosis. The basal bodies migrate toward the nucleus and become intimately associated with the nuclear membrane which is devoid, of ribosomes where adjacent to the basal bodies. The basal bodies replicate at preprophase. The nucleolus fragments at this stage. By prophase the basal body pairs have migrated, to the nuclear poles. Spindle fibers become prominent in the nucleus. The nuclear membrane does not fragment. The nucleus assumes a crescent‐form by metaphase. Polar fenestrae are absent. Kinetochores appear at anaphase. An interzonal spindle elongates as the chromosomes move to the nuclear poles. Daughter nuclei become abscised by an ingrowth of nuclear membrane, leaving behind a separated, degenerating interzonal spindle. Ribosomes reappear on the outer nuclear membrane at late telophase. Nucleoli reform early in cytokinesis. The cleavage furrow, associated microtubules, and endoplasmic reticulum comprise the phycoplast. Cytokinesis proceeds rapidly after the completion of telophase. The basal body‐nucleus relationship becomes reorganized into the typical interphase condition late in cytokinesis. Specific and predictable organelle rearrangements during mitosis have been described. Cell division inC. moewusiiis compared with other algae, especiallyC. reinha

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02735.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYGlucose and galactose uptake ability inCyclotella cryptica(clone WT‐1‐8) and glucose uptake ability inCoscinodiscussp. develop rapidly in the dark. Induction of sugar uptake ability in the dark does not require the presence of sugar in the medium. The sugars are taken up by carrier‐mediated systems. InC. crypticaglucose and galactose are probably taken up by the same system. The capacity of glucose uptake in this recently isolated clone ofC. crypticais nearly 5 times that of a previously studied clone (0‐3A). Other organic compounds, which by themselves do not support heterotrophic growth, can be taken up and respired by both diatoms at considerable rates compared, to glucose and galactose. Therefore, in nature, these diatoms may be able to utilize a variety of dissolved organic compounds as sources of intermediary metabolites and as respiratory sub

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02736.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYA buffered, chelated, defined medium was developed for isolation and growth of acid‐bog flagellates and for physiological studies of bog chlamydomonads.Hydrogen ion tolerances ofChlamydomonas acidophila, C. sphagnophila121 A,C. sphagnophilaIU293, and,C. reinhardiwere determined. OnlyC. acidophilagrew at pH 2.0. It did not grow at pH 7.0 or 8.0 as did the other chlamydomonads tested. Liver fraction “L” and Fe permitted growth ofC. acidophilaat pH 2.0 equal to control growth at pH 5.0. NeitherC. sphagnopliila121A norC. reinhardigrew at pH 2.0 with these additions. Hydrogen ion seems to be excluded from the cell interior of acid‐tolerant species. They remained green (ie,pheophytinization did not occur) when cultured below pH 5.0.C. acidophilagrew in the dark with glucose as sole source of carbon and energy. Acetate, glycolate, and glyoxylate were assimilated in the dark if glucose was also present.C. sphagnophila121A did not grow in the dark on any of the 51 organic carbon compounds tested.C. acidophilaandC. sphagnophila121A seem promising tools for determining biochemical mechanisms responsible for differences in H+tolerances. Presumably specialized cell walls or membranes are i

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02737.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY

摘要:

SUMMARYPseudendoclonium basilienseandTrichosarcina polymorphaare essentially identical with regard to the fine structural details of cell division even though one was previously classified in the Chaetophorales and the other in the Ulvales. Cell division in the 2 genera is also shown to be like that inUlva,as previously suggested might be the case. The combination of mitotic and cytokinetic characteristics common to the 3 genera is distinctive: (1) precocious development of a thick cleavage furrow, (2) centrioles distinctly lateral to polar fenestrae, (3) collapse of the interzonal spindle at telophase, and. (4) a cleavage furrow not associated with microtubules. It is suggested that features of vegetative cell division presently provide the best, characteristics for defining the Ulvaceae and that the use of growth habit should be abandoned. Despite the fact that a phycoplast is not present, in these algae, it is concluded that their affinities lie with genera that do possess a phycoplast.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1974.tb02738.x

出版商:Blackwell Science Inc    

年代:1974

数据来源: WILEY