Document Type

Dissertation

Date of Award

1976

Keywords

Algae, Effect of poisons on plants

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

First Advisor

George Schumacher

Second Advisor

Jacob Fischthal

Third Advisor

Alan H. Haber

Abstract

Algae of many diverse taxonomic units produce water soluble non-crystalline extracellular heteropolysaccharides. These polymers, or mixtures of polymers, usually have a gelatinous consistency and they may be termed “mucilage,” or “pectic,” “sheath,” “capsule” or “gelatinous” material. It may also be termed “algal slime.” It is the purpose of this work to investigate one possible function of at least one variety of algal slime.

The hypothesis to be investigated is that the slime produced by an algal cell affects the susceptibility of that alga to poisons, particularly metal ions. The rationale for this comes from:

A. The observation that algal slimes from diverse sources have considerable chemical similarity. This is true of slimes from many forms of algae, and it is also true of algae from different divisions. This conservatism suggests that the slimes play some significant role(s) in the life of many algae.

B. Consideration of the structure and chemistry of some algal slimes. The prediction can be made that slimes should interact with metal cations in aqueous solution.

C. It has been suggested that an interaction of this sort should have an effect on the susceptibility of the alga to poisons. This has not heretofore been demonstrated.

D. Studies of metal toxicity yield quite varied results. Some species seem to be far more tolerant than others. It is possible that a correlation exists between this and the amount or type of slime produced. Of course, this is not the only factor involved.

Aside from its strictly academic interest, the hypothesis has significance from several viewpoints:

A. If the slime does affect the ionic traffic into the cell, then the physiologist needs to consider this in studying mechanisms of metabolic control.

B. Algae come in contact with potentially toxic levels of metals either naturally (Whitton 1970), from mining or industrial operations (Sparling 1968), or from the use of metal salts, especially those of copper, to control nuisance algal growths (Gratteau 1970).

C. If there is a slime-metal interaction such that some stable complex is formed, then the fate of this complex may be of significance to the rest of the food cycle.

It would seem reasonable to try to elucidate the relationships between algal slime and metal poisoning. As a starting point, one pair of algal species, and one metal were chosen for this project. The proximate goal was to study the interactions of copper with the extracellular, water-soluble polysaccharides of two species of the Chlorophycean desmid, Mesoteanium, and to determine the physiological significance of the interaction in terms of the survival of the algae. The work was divided into several parts:

Phase 1. Study of the growth characteristics of the experimental species. This was necessary because little cultural work has been done with these particular species.

Phase 2. Study of the chemistry and behavior of copper. The interactions of copper and the growth medium were studied, including pH and autoclaving as factors. A suitable scheme of analysis was acquired.

Phase 3. Isolation and Characterization of algal slime. The extracellular polysaccharide was removed from the cells, freed of interfering substances, and characterized.

Phase 4. Behavior of the slime in vitro. The copper-slime interactions were studied and compared to interactions with other similar carbohydrates.

Phase 5. Copper dosing. The dose-responses of the species were compared. Copper-slime complexes were detected from the dosed cultures, including cultures to which extra slime was added. If the interaction has physiological significance, this manipulation should affect the dose-response of the algae.

This work was carried out at two locations: Early work was conducted at the State University of New York at Binghamton, while later work took place at the New York Ocean Science Laboratory, Montauk, NY.

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