Micrococci were commonly isolated from the skins of people living in various regions of the United States. Not all micrococci isolated in this investigation could be identified with the currently recognized species of Micrococcus, viz., M. luteus, M. varians, or M. roseus, and these micrococci therefore became the subject of further taxonomic study. As a result of this study, two new species are proposed: Micrococcus lylae and M. kristinae. The type strains of these species are ATCC 27566 and ATCC 27570, respectively. Numerous strains were isolated that were similar t o M. sedentarius or M. nishinomiyaensis, species that were previously represented by only single strains. (ZoBell's strain 5 4 1 [ ATCC 14392; CCM 3141 is designated herein as the type strain of M. sedentarius.) A few micrococci were left unclassified. A variety of morphological, physiological, biochemical, and genetic characters were examined for their use as taxonomic criteria, and key characters, many of which can be determined by simple laboratory procedures, were selected for species differentiation. The more sophisticated studies of aliphatic hydrocarbons and cell-wall peptidoglycans were also very useful in the taxonomy of the micrococci. The predominant micrococci found on human skin were M. luteus and M. varians.The medical literature has, for many years, made reference to a group of aerobic, saprophytic bacteria known as Sarcina that have been commonly isolated from human skin ( 14, 18,28,29,33). Recent taxonomic studies have indicated that most aerobic strains maintained in various culture collections under the name of Sarcina belong t o the species Micrococcus luteus (Schroeter 1872) Cohn 1872 or Micrococcus varians Migula 1900 (19, 21, 22, 24, 40). In line with this, Marples et al. (30) recently made reference t o the species M. luteus in studies on the aerobic microflora of the human scalp. M. varians has not yet been reported in studies of human skin. However, it was not until 1973 (22) that a comprehensive report on the taxonomic status of this species was made available. Earlier reports were somewhat confusing, and, with the lack of a clearly defined species status, cutaneous isolates may have been simply placed in Baird-Parker's Micrococcus subgroups together with other species (2). The purpose of this investigation was t o classify species of micrococci found on human skin by using the most current taxonomic critieria. We also became involved with evaluating existing taxonomic criteria, exploring new characters, and estimating species variation in cutaneous populations.Some of the preliminary results of this study have been previously reported (W. E. Kloos and K. H. Schleifer, Abst. Annu. Meet. Amer. SOC. Microbiol., 73rd, Miami Beach, p-116, 1973). MATERIALS AND METHODSBacterial straips. Micrococci were isolated from the healthy skins o f two groups of people. One group was composed of 20 people living in Raleigh, N.C., who were sampled once each month for 6-13 months. Samples from people of the Raleigh longitudinal study w...
The lipid profile of seven species of unicellular eukaryotic microalgae grown under controlled conditions was studied with emphasis on the hydrocarbons and the fatty acids as part of a search for oil‐producing algae. Green, slow‐growing colonies of Botryococcus braunii Kutz contained the highest lipid content of 45% based on the organic weight, with an increase to 55% under nitrogen deficiency and with no effect of sodium chloride stress. Ankistrodesmus sp. Thomas, Dunaliella spp., Isochrysis sp., Nannochloris sp. Thomas, and Nitzschia sp. Chapman contained an average of 25% lipids under nitrogen sufficient conditions. Nitrogen deficiency resulted in significant increase in the lipid content in all species but Dunaliella spp., which produced a higher content of carbohydrates. Significant low amounts of acyclic hydrocarbons were detected only in Botryococcus braunii Kutz and not in the other algae. The major hydrocarbon fractions in nitrogen deficient Botryococcus braunii Kutz, Dunaliella salina Thomas, Isochrysis spp. and Nannochloris sp. Thomas were cyclic and branched polyunsaturated components which were identified as various isoprenoid derivatives. The polar lipid composition of glycolipids and phospholipids of all species investigated was fairly typical of photosynthetic eukaryotic algae. Fatty acid composition was species specific, with changes occurring in the relative amounts of individual acids of cells cultivated under different conditions and growth phases. All species synthesized C14:0, C16.0, C18:1, C18:2 and C18:3 fatty acids; C 16:4 in Ankistrodesmus sp. Thomas; C18:4 and C 22.6 in Isochrysis sp.; C16:2, C16:3 and C20:5 in Nannochloris sp. Thomas; C16:2, C16:3 and C20:5 in Nitzschia sp. Chapman. Nitrogen deficiency and salt stress induced accumulation of C18:1 in all treated species and to a lesser extent in Botryococcus braunii Kutz. The low production of hydrocarbons under optimal growth conditions and the high production of hydrocarbons under limited growth conditions cannot support the notion that microalgae can be utilized as biosolar energy converters for the production of liquid fuel, but point to the availability of a variety of neutral and polar lipid products.
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