Comparative physiology, biochemistry, and the taxonomy ofChlorella (Chlorophyceae)

DNA base modification inChlorella

“…Some of these species, however, still comprise strains with varying DNA G + C contents. The most striking example is C. sorokiniana, a species uniquely characterised within the genus Chlorella by growing at high temperatures of 38-42°C (Kessler, 1976(Kessler, , 1985. Whereas DNA of the type strain 211-8k contains 63 real% G + C, up to 75 real% were found for other strains ( Fig.…”

“…1), represents a natural genus (Kessler, 1976;Huss et al, 1986Huss et al, , 1989a. Alternatively, the broad DNA G + C range might be caused by different amounts of repetitive sequences or by a variable degree of DNA base modification such as methylation of cytidine or adenine residues (Rae & Steele, 1978).…”

Caractéristiques photosynthétiques deChlorella sorokinianaShihira & Krauss, en relation avec l'intensité lumineuse et la température. Corrélation avec le taux de croissance

“…Si dC/dt représente le taux de photosynthèse nette de la population d'algues, il est possible de déduire un taux de croissance (Eppley 1968, Peterson 1978, Capblancq 1982, Dauta 1982 (Kessler 1965(Kessler , 1967(Kessler , 1972(Kessler a et b, 1974(Kessler , 1976(Kessler , 1978(Kessler , 1980(Kessler , 1985(Kessler , 1986, liste non exhaustive). Dans des travaux antérieurs (Belkoura & Dauta 1992) nous avons mis en évidence la spécificité du comportement de la souche marocaine de Chlorella sorokiniana en relation avec les conditions héliother-miques du milieu.…”

Identification of the green alga, Chlorella vulgaris (SDC1) using cyanobacteria derived 16S rDNA primers: targeting the chloroplast

“…Chlorella species have been shown to form intracellular symbioses with aquatic invertebrates and protozoa [1], produce hydrogen, tolerate extremes in acid and salt levels, and produce pharmaceutically important natural products [2]. Previous research has determined that there is a deep evolutionary gap between some of the Chlorella species, with some species possessing niche speci¢c properties, such as containing the hydrogen-activating enzyme hydrogenase [3], the ability to liquefy gelatin [4], reduce nitrate and the ability to degrade and tolerate high concentrations (to at least 1% v/ v) of volatile organic compounds (VOCs) such as isopropanol and acetone [5].…”

“…This facilitates the extrapolation of physiological and biochemical information gained to the environmental strains studied. However, various factors such as misidenti¢cation of strains in culture collections [2], inadequate culture conditions which lead to the malformation or loss of identifying features [6] and growth intricacies [3], make it di¤cult in many cases to apply taxonomic guidelines based on culture strains to environmental isolates. The phylogenetic relatedness of organisms can be deduced in principle from the comparison of their genetic sequences.…”