No description available.

Many experiments have been performed with the Warburg apparatus, or variations of this manometric technique, since Warburg's experiments (52, 53) where the effects of cyanides upon dark reactions and of urethanes upon light reactions of photosynthesis were demonstrated. The same basic techniques were utilized in this research in attempting to determine the effects of some coordination complexes upon the apparent photosynthetic rate of Chlorella pyrenoidosa. A second goal of the present paper was to investigate the potential of the Warburg apparatus as a tool for screening algicidal compounds.

Immunocytochemical analyses have demonstrated that the Calvin cycle enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is predominantly localized in the pyrenoid region of chloroplasts of evolutionarily diverse algae. That Rubisco remains pyrenoid-localized at photosynthetically-saturating irradiance in the green alga Chlorella pyrenoidosa indicates a catalytic, rather than storage function for pyrenoid-localized Rubisco. This is further supported by the immunolocalization of Rubisco activase to the pyrenoids of two species of green algae. The exclusion of phosphoribulokinase from the pyrenoids of a red and a green alga indicates that pyrenoids do not possess the full complement of Calvin cycle enzymes. / Thylakoid lamellae traverse the pyrenoids of many algae. The absence of light-harvesting phycoerythrin and of photosystem (PS) II activity, but not PSI activity, from the intrapyrenoid thylakoids of the red alga Porphyridium cruentum indicates a structural and functional heterogeneity between these lamellae and those located in the chloroplast stroma. In contrast, the intrapyrenoid thylakoids of cryptomonads, algae whose chloroplast is thought to have evolved from red algae, possess both PSI and PSII protein complexes. These results are discussed with reference to Rubisco being mainly pyrenoid-localized in these algae.

Many contaminants, such as industrial chemicals, fertilizers, herbicides, pharmaceuticals and heavy metals are released to e environment. 3,4-dichloroaniline（3,4-DCA） originated from degradation of some herbicides such as diuron, propanil and linuron, is toxic to aquatic organisms and affects human being immune system. Triclosan, widely used as antimicrobial agent in pharmaceuticals and personal care products (PPCPs), has been detected as contaminat in various aquatic environments. In this work, green algae were isolated from local environment, then applied for the removal and biodegradation of 3,4-DCA and triclosan. Two axenic pure algae were isolated using the solid agar method. One of the algae was identified morphologically as Desmodesmus sp. based on the experimental results. The other one was identified morphologically as Chlorella pyrenoidosa by accredited authority. At the same time, alga S. obliqnus was obtained commercially. All the three green algae were cultured in tris-acetate-phosphate (TAP) medium. Firstly, the alga C. pyrenoidosa was applied to remove and biodegrade 3,4-DCA with a concentration of 4.6 μg/mL for 7 d. A removal percentage of 78.4% was obtained over a 7-d period. Two major metabolites with less toxicity were identified as 3,4-dichloroformanilide and 3,4-dichloroacetanilide using HPLC-ESI-ion trap-MS. iii Secondly, all the three green microalgae species including C. pyrenoidosa, Desmodesmus sp., and S. obliqnus, were compared in the removal and biodegradation of triclosan in aqueous medium. When triclosan with concentration of 400 ng/mL was cultured with the three algal species separately, triclosan was quickly eliminated from medium in the 1 d cultivation by algae with removal percentages of 62.4%, 92.9% and 99.7% for C. pyrenoidosa, Desmodesmus sp. and S. obliqnus, respectively. The dominant mechanism for the removal of triclosan by C. pyrenoidosa was determined as cellular uptake. Biotransfromation of triclosan involved hydroxylation and methylation, glucose conjugation was determined as the predominant mechanisms for the removal of triclosan by algae Desmodesmus sp. and S. obliqnus. The intermediates from hydroxylation, reductive dechlorination, or ether bond cleavage were immediately subjected to glucosylation and/or methylation via the hydroxyl group of triclosan or introduced, which served as detoxification mechanisms of the chlorinated aromatic chemicals. In order to find the intermediates in the metabolic pathway of triclosan by algae, Desmodesmus sp. was exposed to 400 ng/mL triclosan. 2,4-DCP was detected during the cultivation period 3-12 h using ultra performance liquid performance (UPLC)-ESI-MS/MS. The metabolites from multi metabolic reaction like the glucose conjugate of hydroxylated triclosan were detected in the first 30 min after exposure. The metabolites as products from glucosylation and consecutive hydroxylation and methylation of triclosan or 2,4-DCP were detected after 3 h iv cultivation. To provide more information about the reductive capability of C. pyrenoidosa, the reaction between C. pyrenoidosa and triclosan was investigated. When C. pyrenoidosa was exposed to triclosan with concentration from 100 to 800 ng/mL, more than 50% of triclosan was eliminated by algal uptake from the culture medium during the first 1 h exposure. In the biodegradation experiments, a major metabolite from the reductive dechlorination of triclosan was identified by using liquid chromatography (LC)-ESI-MS. The ability of reductive dechlorination of C. pyrenoidosa might potential application for bioremediation of polychlorinated biphenyls (PCBs) that with similar chemical structure to triclosan, but belonging to the catagory of persistent organic pollutants (POPs). Through the TEM observation, it was found that the triclan treatment resulted in the disruption of the chloroplast of algal cells, which indicated that triclosan may affect membrane metabolism.

The purpose of this paper is to present data on the nature of mixed cultures of algae and bacteria and to report new evidence of growth inhibition of Chlorella by a bacterial contaminant isolated from a soil environment.

No description available.

The demonstration in algae and bacteria of the presence of a high molecular weight polymer of inorganic phosphate has raised questions concerning the metabolic role of the polymer and the mechanism(s) by which it is synthesized and utilized. The purpose of the research described in this dissertation was to determine the relationship of inorganic polyphosphate to the total metabolism of phosphorus by C. pyranoidosa. / Ph. D.

Algal blooms in our streams, lakes and reservoirs have been known to cause nuisance problems. Water treatment problems include clogging of filtration units, taste and odor, turbidity and green coloration of water. Dense algal blooms reduce the recreational value of water and, recently, have been reported to kill fish. Algal blooms have been attributed to increased nutrients in waterways from wastewater discharges and runoff from agricultural land which contains fertilizers and herbicides. A widely used herbicide, 2,4 dichlorophenoxyacetic acid (2,4D), has been found in waters adjacent to land applications in concentrations known to be stimulatory to many plants. The purpose of this study was to evaluate the effect of 2,4D on the growth of Chlorella pyrenoidosa in batch cultures. Cultures were grown over a 12 day period in 2,4D concentrations of 10⁻⁸ to 2 x 10⁻³ M. The culture medium was inoculated to provide 2.0 x 10⁴ cells/ml and incubated under continuous fluorescent lighting at 140, 200 and 220 foot candles and 20 ± 1.0°C. Cell counts and fluorometric readings were made on even days and analyzed by least squares regression and analysis of variance. The results indicate that 2,4D promoted growth of Chlorella pyrenoidosa. Increased growth was discovered with increases in 2,4D concentration from 10⁻⁸ to 2 x 10⁻³ M 2,4D. A concentration of 2 x 10⁻³ M 2,4D appeared to cause slight inhibition when compared to 10⁻³ M 2,4D. Light intensity had little effect on 2,4D utilization by Chlorella. The results of this study indicate that herbicides used currently for weed control may be correlated to increase algal growth and thereby influence water quality. / Master of Science

The endogenous respiration rate and the intracellular ATP/ADP ratio were determined during synchronous growth of a high temperature strain of Chlorella pyrenoidosa in order to correlate their activities with a proposed mechanism for the control of intracellular levels of inorganic acid-insoluble polyphosphate, (Pi)x, during cellular growth and division. / Master of Science

The purpose of this study was to determine the endogenous levels of indole-3-acetic acid throughout the life cycle of Chlorella pyrenoidosa, and to show a correlation between onset of cell division and IAA levels.