Thomas D. Brock

Bio: Thomas D. Brock is an academic researcher from University of Wisconsin-Madison. The author has contributed to research in topics: Algae & Photosynthesis. The author has an hindex of 69, co-authored 242 publications receiving 16310 citations. Previous affiliations of Thomas D. Brock include National Institutes of Health & Case Western Reserve University.

Sulfolobus : A new genus of sulfur-oxidizing bacteria living at low pH and high temperature

Abstract: Sulfolobus is a new genus of bacteria characterized as follows: 1. generally spherical cells producing frequent lobes; 2. facultative autotrophy with growth on sulfur or on a variety of simple organic compounds; 3. unusual cell wall structure devoid of peptidoglycan; 4. acidophilic, pH optimum of 2–3 and range from 0.9–5.8; 5. thermophilic with temperature optimum of 70–75°C and range from 55–80°C (one strain grew at 85°C). The DNA base composition of five strains was determined by cesium chloride density gradient centrifugation and found to be 60–68% guanine plus cytosine. Sulfolobus apparently has no close relationship with any previously described bacteria, either heterotrophic or autrotrophic. Techniques are presented for distinguishing Sulfolobus from Thermoplasma, another genus of acidophilic thermophilic spherically shaped organisms. Sulfolobus has been isolated from a variety of natural acidic thermal habitats, both terrestrial and aquatic. Most isolations have been from habitats in Yellowstone National Park, but strains were also isolated from Italy, Dominica and El Salvador. It is suggested that Sulfolobus may be an important geochemical agent in the production of sulfuric acid from sulfur in high temperature hydrothermal systems.

Thermophilic microorganisms and life at high temperatures

Abstract: 1 Introduction.- Extreme Environments.- Environmental Extremes.- Evolutionary Considerations.- References.- 2 The Habitats.- Origins of Thermal Environments.- Constancy of Temperature.- Long-term Constancy.- The Death of Mushroom Spring.- Locations of Hot Springs Studied.- Choosing Springs for Study.- Effect of Temperature on Physical and Chemical Parameters.- Effect of Temperature on Biologically Active Substances.- Chemistry of Hot Springs.- Bimodal pH Distribution of Hot Springs of the World.- Drilling and Subsurface Chemistry.- References.- 3 The Organisms: General Overview.- Temperature and Species Diversity.- Is There an Upper Temperature for Life?.- The Work of Setchell.- Taxonomic Confusion between Blue-green Algae and Nonchlorophyllous Procaryotes (Bacteria).- Well-characterized Thermophilic Procaryotes.- Thermophilic Eucaryotes.- The Upper Temperature Limit for Eucaryotes.- References.- 4 The Genus Thermus.- Isolation Procedures and Habitat.- Morphology of Thermus aquaticus.- Physiological and Nutritional Characteristics.- Thermostable Enzymes of Thermus aquaticus.- Protein Synthesis.- Lipids and Membranes of Thermus aquaticus.- Final Words.- References.- 5 The Genus Thermoplasma.- Characteristics of Thermoplasma.- DNA Base Composition.- Nomenclature.- Habitats of Thermoplasma.- Specific Isolation Procedures for Thermoplasma.- Serological Studies.- Cellular Stability of Thermoplasma.- The Lipids of Thermoplasma.- Membrane Vesicles and Spin Label Studies.- Intracellular pH.- Osmotic Relations of Thermoplasma.- The Nature of the Yeast Extract Requirement.- Nutrition in the Natural Habitat.- Evolution of Thermoplasma.- References.- 6 The Genus Sulfolobus.- Morphology of Sulfolobus.- Nature of the Cell Wall.- Pili and Attachment to Sulfur.- Taxonomy.- Specific Isolation Procedures.- Habitats.- Temperature Relations.- Serology.- Cellular Stability.- Lipids of Sulfolobus.- Sulfur Oxidation.- CO2 Fixation.- Sulfide Oxidation.- Ferrous Iron Oxidation.- Ferric Iron Reduction.- Heterotrophic Nutrition.- Leaching and Oxidation of Sulfide Minerals.- Growth Rates of Sulfolobus in Nature.- Ecology of Sulfolobus in Hot Acid Soils.- Biogeography and Dispersal.- Evolution of Sulfolobus.- References.- 7 The Genus Chloroflexus.- Isolation and Culture of Chloroflexus.- Morphology of Chloroflexus.- Nutritional Studies on Chloroflexus.- Sulfur Metabolism of Chloroflexus.- Pigments of Chloroflexus.- Physiology of CO2 Fixation.- Habitat of Chloroflexus.- Ecology of Chloroflexus in Hot Springs.- Adaptation of Chloroflexus to Various Light Intensities.- Evolutionary Significance of Chloroflexus.- References.- 8 The Thermophilic Blue-green Algae.- Cultivation of Thermophilic Blue-green Algae.- The Genus Mastigocladus.- The Genus Synechococcus.- Light Responses and Adaptation of Thermophilic Blue-green Algae.- The Effect of Wide Temperature Fluctuations on Blue-green Algae.- References.- 9 The Genus Cyanidium.- Culture, Isolation, and Structure of Cyanidium.- Lipids of Cyanidium.- Pigments and Photosynthesis of Cyanidium.- Habitat of Cyanidium.- Temperature Limits of Cyanidium.- Absence of Temperature Strains in Cyanidium.- Growth Rates of Cyanidium in Nature.- Relationship to pH.- Effect of Light Intensity.- Heterotrophy of Cyanidium: Ecological Significance.- Nitrogen Nutrition of Cyanidium.- Biogeography of Cyanidium.- References.- 10 Life in Boiling Water.- Bacterial Growth Rates above 90 C.- Upper Temperature for Life.- Limits of Microbial Existence: Temperature and pH.- The Bacteria of Boulder Spring.- The Bacteria of Octopus Spring.- In Retrospect.- References.- 11 Stromatolites: Yellowstone Analogues.- Siliceous Algal and Bacterial Stromatolites in Hot Springs and Geyser Effluents of Yellowstone National Park.- Controls of Stromatolite Morphogenesis and Lamination Production.- Studies on the Reasons for Node Formation by Phormidium.- Photosynthesis in Intact and Dispersed Nodes.- Bacterial Stromatolites.- References.- 12 A Sour World: Life and Death at Low pH.- Lower pH Limit for Living Organisms.- Lower pH Limit for the Existence of Blue-green Algae.- The Eucaryotic Alga Zygogonium.- Bacteria.- Rate of Sulfuric Acid Production in Yellowstone Solfataras.- References.- 13 The Firehole River.- General Features of the River.- Thermal Regime of the River.- Chemical Alteration of the River.- Biological Effects.- Algal Studies.- Bacterial Studies.- Fish in the Firehole River.- Conclusion.- References.- 14 Some Personal History.- Personnel Involved in Yellowstone Research Project.- Bibliographic Note.- Public Service.- Movies and Television.- The West Yellowstone Laboratory.- The Decision to Quit.

Thermus aquaticus gen. n. and sp. n., a Nonsporulating Extreme Thermophile

Abstract: The isolation of a new thermophilic bacterium, Thermus aquaticus gen. n. and sp. n., is described. Successful enrichment requires incubation at 70 to 75 C, and the use of nutrient media relatively dilute with respect to the organic components. Strains of T. aquaticus have been isolated from a variety of thermal springs in Yellowstone National Park and from a thermal spring in California. The organism has also been isolated from man-made thermal habitats, such as hot tap water, in geographical locations quite distant from thermal springs. Isolates of T. aquaticus are gram-negative nonsporulating nonmotile rods which frequently form long filaments at supraoptimal temperatures or in the stationary phase. All isolates form a yellow cellular pigment, probably a carotenoid. A characteristic structure formed by all isolates is a large sphere, considerably larger than a spheroplast. These large spheres, as well as lysozyme-induced spheroplasts, are resistant to osmotic lysis. Deoxyribonucleic acid base compositions of four strains were determined by CsCl density gradient ultracentrifugation and found to be between 65.4 and 67.4 moles per cent guanine plus cytosine. The growth of all isolates tested is inhibited by fairly low concentrations of cycloserine, streptomycin, penicillin, novobiocin, tetracycline, and chloramphenicol. Nutritional studies on one strain showed that it did not require vitamins or amino acids, although growth was considerably faster in enriched than in synthetic medium. Several sugars and organic acids served as carbon sources, and either NH4+ or glutamate could serve as nitrogen source. The organism is an obligate aerobe and has a pH optimum of 7.5 to 7.8. The optimum temperature for growth is 70 C, the maximum 79 C, and the minimum about 40 C. The generation time at the optimum is about 50 min. The possible relationships of this new genus to the myxobacteria, flexibacteria, and flavobacteria are discussed.

Life at high temperatures

Abstract: Water environments with temperatures up to and above boiling are commonly found in association with geothermal activity. At temperatures above 60 degrees C, only bacteria are found. Bacteria with temperature optima over the range 65 degrees to 105 degrees C have been obtained in pure culture and are the object of many research projects. The upper temperature limit for life in liquid water has not yet been defined, but is likely to be somewhere between 110 degrees and 200 degrees C, since amino acids and nucleotides are destroyed at temperatures over 200 degrees C. Because bacteria capable of growth at high temperatures are found in many phylogenetic groups, it is likely that the ability to grow at high temperature had a polyphyletic origin. The macromolecules of these organisms are inherently more stable to heat than those of conventional organisms, but only small changes in sequence can lead to increases in thermostability. Because of their unique properties, thermophilic organisms and their enzymes have many potential biotechnological uses, and extensive research on industrial applications is under way.

Characterization of an acetate-decarboxylating, non-hydrogen-oxidizing methane bacterium.

Abstract: A methanogenic bacterium, commonly seen in digested sludge and referred to as the "fat rod" or Methanobacterium soehngenii, has been enriched to a monoculture and is characterized. Cells are gramnegative, non-motile and appear as straight rods with flat ends. They form filaments which can grow to great lengths. The structure of the outer cell envelop is similar to Methanospirillum hungatii. The organism grows on a mineral salt medium with acetate as the only organic component. Acetate is the energy source, and methane is formed exclusively from the methyl group. Acetate and carbon dioxide act as sole carbon source and are assimilated in a molar ratio of about 1.9:1. The reducing equivalents necessary to build biomass from these two precursors are obtained from the total oxidation of some acetate. Hydrogen is not used for methane formation and is not needed for growth. Formate is cleaved into hydrogen and carbon dioxide. Coenzyme M was found to be present at levels of 0.35 nmol per mg of dry cells and F420 amounted to 0.55 microgram per mg protein. The mean generation time was 9 days at 33 degrees C.

Standard methods for the examination of water and waste water.

Abstract: 1. Discussion Alkalinity of a water is its acid-neutralizing capacity. It is the sum of all the titratable bases. The measured value may vary significantly with the end-point pH used. Alkalinity is a measure of an aggregate property of water and can be interpreted in terms of specific substances only when the chemical composition of the sample is known. Alkalinity is significant in many uses and treatments of natural waters and wastewaters. Because the alkalinity of many surface waters is primarily a function of carbonate, bicarbonate, and hydroxide content, it is taken as an indication of the concentration of these constitutents. The measured values also may include contributions from borates, phosphates, silicates, or other bases if these are present. Alkalinity in excess of alkaline earth metal concentrations is significant in determining the suitability of a water for irrigation. Alkalinity measurements are used in the interpretation and control of water and wastewater treatment processes. Raw domestic wastewater has an alkalinity less than, or only slightly greater than, that of the water supply. Properly operating anaerobic digesters typically have supernatant alkalinities in the range of 2000 to 4000 mg calcium carbonate (CaCO3)/L. 1

Sorting Things Out: Classification and Its Consequences

Abstract: What do a seventeenth-century mortality table (whose causes of death include "fainted in a bath," "frighted," and "itch"); the identification of South Africans during apartheid as European, Asian, colored, or black; and the separation of machine- from hand-washables have in common? All are examples of classification -- the scaffolding of information infrastructures. In Sorting Things Out, Geoffrey C. Bowker and Susan Leigh Star explore the role of categories and standards in shaping the modern world. In a clear and lively style, they investigate a variety of classification systems, including the International Classification of Diseases, the Nursing Interventions Classification, race classification under apartheid in South Africa, and the classification of viruses and of tuberculosis. The authors emphasize the role of invisibility in the process by which classification orders human interaction. They examine how categories are made and kept invisible, and how people can change this invisibility when necessary. They also explore systems of classification as part of the built information environment. Much as an urban historian would review highway permits and zoning decisions to tell a city's story, the authors review archives of classification design to understand how decisions have been made. Sorting Things Out has a moral agenda, for each standard and category valorizes some point of view and silences another. Standards and classifications produce advantage or suffering. Jobs are made and lost; some regions benefit at the expense of others. How these choices are made and how we think about that process are at the moral and political core of this work. The book is an important empirical source for understanding the building of information infrastructures.

Membrane Technology and Applications

Abstract: Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.