Sexual agglutination factor from Chlamydomonas eugametos

Planta ◽  
1981 ◽  
Vol 153 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Alan Musgrave ◽  
Ed van Eijk ◽  
Ruud te Welscher ◽  
Rob Broekman ◽  
Peter Lens
Keyword(s):  
Sexual Agglutination ◽  
Chlamydomonas Eugametos

scholarly journals Sexual Agglutination in the Unicellular Green Alga Chlamydomonas eugametos

1985 ◽  
Vol 79 (3) ◽  
pp. 740-745 ◽  
Author(s):  
Frans M. Klis ◽  
Marieke R. Samson ◽  
Egbert Touw ◽  
Alan Musgrave ◽  
Herman van den Ende
Keyword(s):  
Green Alga ◽  
Sexual Agglutination ◽  
Chlamydomonas Eugametos ◽  
Unicellular Green Alga

Sexual agglutination in Chlamydomonas eugametos before and after cell fusion

Planta ◽  
1985 ◽  
Vol 166 (2) ◽  
pp. 234-243 ◽  
Author(s):  
A. Musgrave ◽  
P. de Wildt ◽  
F. Schuring ◽  
K. Crabbendam ◽  
H. van den Ende
Keyword(s):  
Cell Fusion ◽  
Sexual Agglutination ◽  
Chlamydomonas Eugametos ◽  
Before And After

scholarly journals Monoclonal antibodies directed against the sexual binding site of Chlamydomonas eugametos gametes.

1988 ◽  
Vol 107 (1) ◽  
pp. 177-189 ◽  
Author(s):  
W Homan ◽  
A Musgrave ◽  
H de Nobel ◽  
R Wagter ◽  
D de Wit ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Immunofluorescence Test ◽  
Sexual Agglutination ◽  
Class A ◽  
Fab Fragments ◽  
Chlamydomonas Eugametos ◽  
Low Concentrations ◽  
Class B ◽  
Positive Class ◽  
High Concentrations

Monoclonal antibodies were raised against the mt- sexual agglutinin of Chlamydomonas eugametos gametes. Those that blocked the agglutination site were selected. They were divided into two classes dependent upon whether they gave a weak (class A) or clear positive (class B) reaction with mt- flagellar membranes in an ELISA and an indirect immunofluorescence test using glutaraldehyde-fixed mt- gametes. Class A antibodies were shown to be specific for the agglutinin in an extract of mt- gametes, based on results from immunoblotting, immunoprecipitation, affinity chromatography, and the absence of a reaction with nonagglutinable cells. Surprisingly, class A mAbs also recognized two mt+ glycoproteins, one of which is the mt+ agglutinin. Class B antibodies were shown to bind to several glycoproteins in both mt- and mt+ gametes, including the mt- agglutinin. Fab fragments from class A mAbs blocked the sexual agglutination process, but those from class B did not, even though the parent antibody did. We conclude that the class A epitope lies in or close to the agglutination site of the mt- agglutinin, whereas the class B epitope lies elsewhere on the molecule. We also conclude that the mt- agglutinin is the only component on the mt- flagellar surface directly involved in agglutination. Class A mAbs were found to elicit several reactions displayed by the mt+ agglutinin. They bound to the mt- agglutinin on gamete flagella and induced most of the reactions typical of sexual agglutination, with the exception of flagellar tip activation. None of these reactions was induced by Fab fragments. High concentrations of class A mAbs completely repressed the sexual competence of live mt- gametes, but low concentrations stimulated cell fusion.

The Role of Temperature and Heterotrophism in Determining Crude Oil Toxicity

1975 ◽  
Vol 10 (1) ◽  
pp. 73-83
Author(s):  
J.E.S. Graham ◽  
T.C. Hutchinson
Keyword(s):  
Crude Oil ◽  
Aqueous Extract ◽  
Chlorella Vulgaris ◽  
Nutrient Medium ◽  
General Pattern ◽  
Growth Stimulation ◽  
Aqueous Extracts ◽  
Chlamydomonas Eugametos ◽  
Wide Range ◽  
Oil Toxicity

Abstract Crude oil spills are increasingly likely to occur from drilling, pumping and transportation activities as oil development proceeds at a rapid pace. These spills may occur over the wide range of climatic conditions which obtain in Canada. Little is known of oil toxicity at different temperatures; consequently, laboratory studies were made of the variability of the toxicity of aqueous extracts of a Norman Wells crude oil to freshwater algae over the temperature range 5°C to 35°C. Two unicellular green algae were studied: Chlamydomonas eugametos and Chlorella vulgaris. Their response (measured by cell numbers) varied with temperature and species. Whereas Chlamydomonas eugametos showed a general pattern of growth inhibition by oil at all temperatures with maximum inhibition at 25°C, Chlorella vulgaris showed general growth stimulation by oil with maximum stimulation at 25°C, this temperature was chosen for all further experimentation. All experiments were done using unialgal cultures and sterile technique. Cells were grown in 50 ml of nutrient medium (BBM) in 125 ml Erlenmeyer flasks. Such flasks allow gas exchange and permit loss of volatile hydrocarbons. Aqueous extracts were made by slowly stirring 5% crude oil with the nutrient medium for six hours using a magnetic mixer. The extract was then allowed to sit for two to four hours before the lower fraction was drawn off for use. Experiments were carried out in controlled environment chambers (±2°C) with a twelve hour light-dark cycle. All further experiments used a similar methodology. (Note: Chlamydomonas eugametos experiments were carried out on a rotary shaker at 125 rpm.) An attempt was made to determine the reason for the remarkable stimulation in growth of Chlorella vulgaris #29 at 25°C. This organism has been described in the literature as heterotrophic. Thus three reasons for stimulation seemed possible: 1. heterotrophic uptake of hydrocarbons directly from solution; 2. heterotrophic uptake of organic compounds formed or released by microbial breakdown of hydrocarbons (the aqueous extract of crude was not sterile); or 3. the use of CO2 released to solution by microbial respiration. The original experiment was repeated in the dark at 20°C to determine if stimulation still occurred. It did not, since cells exposed to the aqueous extract decreased in numbers. However, after two weeks the cells were illuminated and even though experimental flasks started off with depleted populations, they outgrew the control cells within two weeks. This suggested that if stimulation was related to heterotrophism, it must, at least in this case, have been the unusual case of photoheterotrophism. The reasons for this stimulation of growth are currently under investigation. Several methods are being employed to investigate the suspected heterotrophism. Experiments will be done to determine whether light energy is essential to the stimulation. Two varieties of Chlorella vulgaris, i.e. #29 and #260 are heterotrophic and autotrophic respectively, are to be used in experiments. Sterile aqueous extracts made by pressure ultrafiltration will be used. These experiments should determine whether algal growth stimulation is related to heterotrophism or whether microbial degradation of hydrocarbons is the real source of stimulation. Although the toxicity of crude oil may be rapidly ameliorated by physical and/or biological phenomena, one must still be aware of the possibility of a large input of organic carbon causing extensive eutrophication. Thus both toxicity and eutrophication will cause a selection, in terms of survival, in a natural environment. It is evident that although an oil spill may not totally destroy an ecosystem, it will certainly alter its natural composition considerably.

The eyespot of Chlamydomonas eugametos: a freeze-etch study

1973 ◽  
Vol 51 (4) ◽  
pp. 817-819 ◽  
Author(s):  
Kazuo Nakamura ◽  
D. F. Bray ◽  
J. W. Costerton ◽  
E. B. Wagenaar
Keyword(s):  
Cleavage Plane ◽  
Chloroplast Membrane ◽  
Ordered Arrays ◽  
Chlamydomonas Eugametos

The ultrastructure of the eyespot region of Chlamydomonas eugametos was studied with the freeze-etch technique. In the region of the eyespot the outer chloroplast membrane, when fractured medially, showed the presence of bulgings which appeared as either depressions or bumps depending on the cleavage plane. These deformations of the outer chloroplast membrane produced by the granules of the eyespot are about 80 mμ in diameter and form ordered arrays of 800 or more particles.

scholarly journals Sexual agglutination inChlamydomonas eugametosis mediated by a single pair of hydroxyproline-rich glycoproteins

1992 ◽  
Vol 97 (1-2) ◽  
pp. 101-105 ◽  
Author(s):  
Marinus Versluis ◽  
Frans Schuring ◽  
Frans M. Klis ◽  
Piet Egmond ◽  
Herman Ende
Keyword(s):  
Single Pair ◽  
Sexual Agglutination
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