Phylogenetic identification and in situ detection of individual microbial cells without cultivation.

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

Standard methods for the examination of water and waste water.

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.

https://www.reciis.icict.fiocruz.br/index.php/reciis/article/download/794/1436

Sorting Things Out: Classification and Its Consequences

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.

Membrane Technology and Applications

Bacteriocins of gram-positive bacteria.

The effect of water potential on the growth of two strains of Thiobacillus ferroxidans was determined by adding defined amounts of sodium chloride or glycerol to the culture medium. The two strains differed slightly, and the most tolerant strain had a minimum water potential for growth of -15 to -32 bars when sodium chloride was used and -6 bars when glycerol was used. In another approach, the limiting water potential was determined by equilibrating small amounts of culture medium with atmospheres of relative humidities equivalent to specific water potentials, and the ability of the organism to grow and oxidize ferrous iron was determined. Under these conditions, which are analogous to those which might control water potential in a coal refuse pile or copper leaching dump, the lower limit at which iron oxidation occurred was -23 bars. The water potential of some coal refuse materials in which T. ferrooxidans was present were determined, and it was found that the water potentials at which the organism was active in these habitats were similar to those at which it was able to grow in culture. However, marked variation in water potential of coal refuse materials was found, presumably due to differences in clays and organic materials, and some coal refuse materials would probably never have water potentials at which the organism could grow. Some literature on the water potentials in copper leach dumps is reviewed, and it is concluded that control of water potential is essential to maximize the success of leaching operations. Because adequate drainage is necessary in a leach dump to ensure sufficient aeration, in many cases water availability in leach dumps may restrict the development of the bacterium necessary for the process.

Effect of water potential on growth and iron oxidation by Thiobacillus ferrooxidans.

Production of sulfuric acid in vapor-dominated hydrothermal systems is primarily a bacterial process. The rate of production of sulfuric acid was measured in springs in several acid-altered areas in Yellowstone National Park. Most of these springs lack surface water flow, but water enters and leaves these springs at approximately constant rates via underground seepage. The rate of water exchange in these steady-state systems was measured by enriching the springs with sodium chloride and measuring the rate at which the chloride ion was diluted. In all cases, the added chloride was diluted at an exponential rate, and half-times for dilution were calculated. The rate at which sulfuric acid was being produced was calculated from a knowledge of dilution rate and volume of the springs and from measurement of the sulfuric-acid concentrations of the waters. In several small springs, flow rate was measured more directly by draining the springs and measuring the rate at which water returned.

These studies showed that water in acid springs enters as cold acid ground water, which is steam heated within the source pool. It was possible to estimate how much of the sulfuric acid in a given spring could have been produced in situ, and how much entered by underground seepage. In springs with pool volumes of 2,000 1 or less, most of the sulfuric acid was produced outside the spring, probably by bacteria present in the nearby acid-altered soil. In springs with pool volumes around 106 1, most of the sulfuric acid was produced in situ by resident bacterial populations. The techniques used may have wider utility in biogeochemical investigations.

Rate of Sulfuric-Acid Production in Yellowstone National Park

Sulfur dioxide in geothermal waters and gases

Experiments were performed to determine whether the fungal component of the lichen thallus might enable the algal component to function under conditions of moisture stress at which it would be unable to function if free-living. Four lichens were used: Lepraria membranacea Ach., Cladonia submitis Evans, Usnea substerilis Mot. and Letharia vulpina (L.) Hue, collected from diverse geographical locations. Moisture stress was quantified using the water potential concept, and water potential was controlled both osmotically and matrically. The function of the alga was evaluated by measuring photosynthesis with a 14C technique. Photosynthesis of whole and ground lichen thalli was measured at different water potentials. Lowest water potentials permitting photosynthesis by whole lichen thalli ranged from-56 to-307 bar, and lowest potentials for the separated algal component ranged from-7 to-145 bar. In all cases the alga was able to photosynthesize at lower water potentials within the lichen thallus than when liberated. The grinding process did not harm the alga. It is suggested that one function of stored carbohydrate in the lichen fungus may be to increase internal osmotic pressure sufficiently so that the fungus thallus can absorb moisture from atmospheres of reduced humidity. If water secretion then occurred, some of this moisture could be made available to the alga.

The effect of water potential on photosynthesis in whole lichens and in their liberated algal components.

a hydrophobic cell mass. This phenomenon has been developed into a quantitative assay for agglutinability which has made it possible to study the mechanism of this attraction (Brock, J. Bacteriol., 75, 697, 1958). Work to be published elsewhere has shown that the two mating types do not differ in electrostatic charge or degree of hydration. Rather, the agglutination seems to be related to the presence of specific cell components on the two strains which are complementary to each other, and the reaction may be analogous to an antibody-antigen reaction. In the work to be reported here, it will be shown that one of the mating types (strain 21) requires a specific protein for agglutination, whereas the other mating type (strain 5) does not require such a protein. This is the first demonstration of a molecular basis for mating type compatibility in a fungus. The components responsible for agglutination exist on the cell wall. Cell walls isolated by mechanical disintegration with glass beads exhibit strong agglutination, even after extensive washing. However, since this yeast is difficult to disintegrate quantitatively, the work to be reported here is with whole cells prepared as described previously, and killed by heating to 100 C for 5 min. This heating intensifies the agglutination and eliminates autolysis during storage. When cell suspensions containing about 500 mg wet weight per ml were incubated with 1000 ,ug per ml of trypsin in 0.02 M tris(hydroxymethyl)aminomethane (Tris) buffer, a rapid removal of protein from the cell surfaces occurred. After 1 hr at 37 C, the cells were removed by centrifugation, washed, and assayed for agglutinability. The supernatant fluids were assayed for protein with the Folin phenol reagent. The results in table 1 demonstrate that onlv the agglutinability of strain 21 is affected, although almost identical amounts of protein are removed from both strains. Further tests with lower concentrations of trypsin have resulted in essentially the same amount of protein being removed in a longer period of time. Anthrone tests indicate that the trypsin is also removing carbohydrate material. Eddy (J. Inst. Brewing, 64, 19-21, 1958) has shown that trypsin and other proteolytic enzymes are able to remove a protein-mannan complex from the surface of flocculant brewer's yeasts which is apparently necessary for flocculation (agglutination) to occur. The conclusion seems reasonable that trypsin is removing a carbohydrate-protein complex from the surface of cells of H. uingei. Although almost identical amounts of protein are removed from both cell types, only the agglutination of one of these cell types is affected. Thus it is possible to differentiate between the two mating types of this yeast. If a protein is not responsible for the be-

Thomas D. Brock

Papers

Effect of water potential on growth and iron oxidation by Thiobacillus ferrooxidans.

Rate of Sulfuric-Acid Production in Yellowstone National Park

Sulfur dioxide in geothermal waters and gases

The effect of water potential on photosynthesis in whole lichens and in their liberated algal components.

Protein as a specific cell surface component in the mating reaction of Hansenula wingei.