Joseph C. O'Kelley

The effect of atrazine, 2,4-D, methoxychlor, carbaryl and diazinon on the growth of planktonic algae

The effect of various concentrations of atrazine, 2,4-D (butoxy ethanol ester), methoxychlor, carbaryl and diazinon on the growth of 36 isolates of planktonic algae was studied. No genera toxicity of methoxychlor near saturating concentrations (0·01 p.p.m.) was demonstrated. The butoxy ethanol ester of 2,4-D was toxic to some test organisms at a concentration of 4 p.p.m. Atrazine inhibited growth generally at 1 p.p.m. and higher, and diazinon and carbaryl were toxic at concentrations of 10 and 25 p.p.m.

MITOSIS AND CLEAVAGE DURING ZOOSPOROGENESIS IN SEVERAL COCCOID GREEN ALGAE1

The fine structure of mitosis and cleavage in Axilosphaera vegetata Cox & Deason, Chlorococcum echinozygotum Starr, Chlorosarcinopsis eremi Chantanachat & Bold, Nautococcus mammilatus Korshikoff, N. terrestris Archibald, N. soluta Archibald, Neospongiococcum solitarium Deason, and Tetracystis aeria Brown & Bold was observed. All possess a phycoplast, but differences in basal body position during mitosis were observed. Nautococcus mammilatus differs from the others as protoplast rotation occurs in many cells prior to cleavage.

FINE STRUCTURE OF MITOSIS AND CLEAVAGE IN FRIEDMANNIA ISRAELENSIS (CHLOROPHYCEAE: CHLOROSARCINACEAE)1

Observations on the ultrastructure of Friedmannia israelensis Chantanachat & Bold revealed the presence of a phycoplast and zoospores with cruciate rootlets. During mitosis, the nuclear envelope partially disintegrates and the basal bodies remain at the cell surface on either side of the developing cleavage furrow. The events during mitosis and cleavage in Friedmannia resemble those reported in the other green algae, Platymonas and Pleurastrum.

Loss of five pesticides from cultures of twenty-one planktonic algae

In an earlier paper the authors utilized thirtysix isolates of planktonic algae to study the effect of atrazine, carbaryl, methoxychlor, diazinon and 2,4-D (butoxy ethanol ester) on growth (BUTLER et al. 1974). At the end of the growth period the cultures were also analyzed by gas chromatography to collect evidence that certain strains might metabolize the pesticides at a significant rate. The evidence sought in this case was the disappearance of the pesticides from cultures of actively growing algae. This report concerns the loss of the five pesticides from actively growing cultures.

Effect of Strontium Replacement for Calcium on Production of Motile Cells in Protosiphon

Protosiphon botryoides Klebs grows without evident zoosporogenesis in inorganic media in which strontium is substituted for calcium. Growth is 50 to 90 percent of that obtained with calcium; when sodium is substituted for calcium, there is no appreciable growth. Motility was observed at or above CaCl2. 2H2O levels of 5 mg/lit., with or without strontium.

LIGHT INDUCED SYNCHRONIZATION OF ALGAL SPECIES THAT DIVIDE PREFERENTIALLY IN DARKNESS

Abstract— Three algal species (Protosiphon botryoides, Chlorella pyrenoidosa and Chlamy‐domonas gymnogama) which divide preferentially at night during natural or simulated day‐night conditions are shown to have cell division inhibited by light in the blue region of the visible spectrum (400–500 nm) and stimulated by the remainder of this spectrum (500–730 nm). Synchronous division has been established in cultures of these organisms on a circadian or longer period by alternating fluorescent cool‐white light and cool‐white with the blue component removed. This procedure is suggested as potentially superior to other methods for synchronizing cultures of algae that prefer, in nature, to undergo cell division at night. Where this procedure does not work it is recommended that an action spectrum for cell division be obtained, since this may provide information for achieving optimal synchrony through the use of other specific wavelength regimes.

A STUDY OF LIGHT INTENSITY, PERIODICITY, AND WAVELENGTH ON ZOOSPORE PRODUCTION BY PROTOSIPHON BOTRYOIDES KLEBS12

When mature Protosiphon cells were placed in darkness, zoospore production was more extensive and was completed in a shorter time at a temperature of 27 C than at 22 or 15 C. Cool‐white fluorescent (Sylvania) light inhibited the process measurably at a radiation intensity of 0.6±103 ergsjcm2‐sec; inhibition was 96% complete at 14±103 ergs/cm2‐sec. For mature cells previously grown under repeated 12‐12 hr light‐dark cycles, a dark period of approximately 2 hr at 22 C allowed cell division to proceed to a stage such that reillumination did not inhibit continued development of zoospores. Monochromatic light from 402 to approximately ‐494 nm, as compared to darkness, inhibited zoospore formation; maximal inhibition was at 432‐461 nm. In contrast, monochromatic light from 522 to 726 nm stimulated zoospore formation relative to darkness. Synchronous zoospore production was obtained using the following regimes: (A) 12 hr cool‐white alternated with 12 hr yellow, (B) 12 hr cool‐white alternated with 12 hr blue. Under regime A synchronous zoospore release (following synchronous production) occurred near the end of the yellow irradiation period, while under regime B it occurred near the end of the cool‐white irradiation period. The significance of this in terms of photoprocesses and possible photoreceptors is discussed.

ENVIRONMENTAL FACTORS AND SEXUAL EXPRESSION IN CHLOROCOCCUM ECHINOZYGOTUM (CHLOROPHYCEAE)1

Several environmental factors affected total growth and zygospore production in Chlorococcum echinozygotum Starr. The temperature range at which zygospore production occurred was more restricted than the range that supported vegetative growth. Light intensity had little effect upon zygospore formation: gamete production and gamete pairing occurred in darkness. Zygospore production occurred over a wide pH range; bicarbonate had a minor effect upon zygospore formation. Nitrogen concentration was the factor of primary importance. As the level of nitrogen supplied as nitrate, ammonia, urea and asparagine in the medium was increased, zygospore production first increased (over no nitrogen) at low levels and then decreased at high levels. All levels of glutamine supplied reduced zygospore production. A possible way in which nitrogen concentration in the medium and sexual expression are linked is discussed.

OCCURRENCE OF GLYCOLATE DEHYDROGENASE AND GLYCOLATE OXIDASE IN SOME COCCOID, ZOOSPORE-PRODUCING GREEN ALGAE1

Twenty‐seven species of coccoid, zoospore‐producing green algae representing 16 genera in the Chlorococcales and Chlorosarcinales were assayed for glycolate oxidase or glycolate dehydrogenase. Only Planophila terrestris Groover & Bold and Fasciculochloris boldii Trainor, contained glycolate oxidase whereas the others contained glycolate dehydrogenase. Representative algae were grown under varying conditions and assayed to determine any effects on these glycolate enzymes. Although specific rates of enzyme activity often varied widely, the form of glycolate enzyme present was not affected.

FLAVIN AS AN ACTIVE COMPONENT OF THE PHOTOREVERSIBLE PIGMENT SYSTEM OF THE GREEN ALGA PROTOSIPHON BOTRYOIDES KLEBS

Abstract— The photoreversible pigment system from Protosiphon botryoides Klebs can be separated into two fractions, which are individually inactive photobiologically, but can be recombined to form an active system. One fraction contains a component stable to combined heat and dilute acid treatment; this component can be replaced by flavin nucleotides. An essential component in the second fraction is heat labile. A similar pigment system has been isolated from other species of green algae.