Showing papers by "University of Wisconsin-Madison published in 1969"
TL;DR: A simple internal calibration technique was used to construct accurate molecular weight-mobility profiles on polyacrylamide gels with well characterized proteins, and the existence of a "critical point" was observed for small polypeptides, in accord with a model in which the protein somehow organizes the sodium dodecyl sulfate anions into a micellar complex of definite size.
891 citations
690 citations
TL;DR: In the early 1900s, it was known that motile bacteria are attracted to a variety of small organic molecules as mentioned in this paper, but few scientists were interested in bacterial chemotaxis, probably because they were unwilling to believe that these lowly organisms possessed any capability for information processing or could exhibit even simple forms of behavior.
Abstract: For a hundred years it was known that motile bacteria are attracted to a variety of small organic molecules. However, few scientists were interested in bacterial chemotaxis, probably because they were unwilling to believe that these lowly organisms possessed any capability for information processing or could exhibit even simple forms of behavior. Despite evidence to the contrary, it was generally assumed that chemotaxis and metabolism were hopelessly entwined. Bacteria simply congregated where the food was; after all, that was where growth rates were fastest. Julius Adler broke this prejudice. Undaunted by peer pressure, Adler set out to uncover the molecular basis for bacterial chemotaxis and, in particular, to test rigorously the perceived connection between this phenomenon and metabolism. First he modified a method developed by Pfeffer in the 1880s to permit a quantitative analysis of chemotaxis with Escherichia coli, an experimentally tractable organism. Basically this method involves inserting a capillary containing an attractant solution into a suspension of bacteria and then counting the cells that swim into the tube after a defined incubation period. Legend has it that he searched the sewers of Madison, Wis., to find an intelligent strain of E. coli. Domesticated strains, which are used to a life of luxury, had become either stupid or paralyzed. The paper is written in a beautifully clear, Socratic style; questions are posed and answers are provided. With this quantitative assay, Adler presented five lines of evidence demonstrating that bacteria have chemoreceptors for attractants: (i) some metabolites fail to attract, (ii) some attractants cannot be metabolized, (iii) attractants can be detected even when cells are flooded with metabolites, (iv) competition is observed with structurally related attractants, and (v) mutants defective in chemotaxis can still metabolize the molecule in question. Moreover, using attractant competition and mutant analysis, he went on to identify at least five different chemoreceptors. Appropriately enough, the paper ends with a section entitled “Implications for neurobiology and behavioral biology.” Adler's elegantly simple experiments demonstrated that bacteria such as E. coli can sense and process environmental information with surprising sophistication. Now many scientists were “attracted” to chemotaxis, and the field grew exponentially. What is remarkable is the diversity of these scientific converts. They include mathematicians and physicists, biochemists and structural biologists, geneticists and molecular biologists, and neurobiologists. Despite the fact that the components of E. coli's “brain” have been identified and analyzed in great detail, important questions remain, including the basis for the large range of ligand sensitivity and the mechanisms of signal amplification and adaptation. Because these questions are fundamental to any sensory system, it is likely that bacterial chemotaxis will remain at the forefront of this important research field. Julius Adler spawned an enormously productive enterprise. THOMAS J. SILHAVY
615 citations
TL;DR: The study of political influence in the West has for the most part focused on the process by which interest groups affect the content of legislation; hence, the input process has occupied the center of attention as mentioned in this paper.
Abstract: The study of political influence in the West has for the most part focused on the process by which interest groups affect the content of legislation; hence, the input process has occupied the center of attention.Students of politics in the new states of Africa and Asia who have adopted this perspective, however, have been struck by the relative weakness both of interest structures to organize demands and of institutionalized channels through which such demands, once organized, might be communicated to decisionmakers. The open clash of organized interests is often conspicuously absent during the formulation of legislation in these nations. To conclude from this, however, that the public has little or no effect on the eventual “output” of government would be completely unwarranted. Between the passage of legislation and its actual implementation lies an entirely different political arena that, in spite of its informality and particularism, has a great effect on the execution of policy.Much of the expression of political interests in the new states has been disregarded because Western scholars, accustomed to their own politics, have been looking in the wrong place. A large portion of individual demands, and even group demands, in developing nations reach the political system, not before laws are passed, but rather at the enforcement stage.
468 citations
TL;DR: In this paper, the authors developed methods for the measurement of real capital input based on perpetual inventory estimates of capital stock and corresponding estimates of service prices, which are adjusted for relative utilization of capital.
Abstract: The purpose of this paper is to develop methods for the measurement of real capital input. These methods are based on perpetual inventory estimates of capital stock and corresponding estimates of capital service prices. Stocks and service prices are adjusted for relative utilization of capital. The resulting estimates represent a separation of income from capital into price and quantity components. Estimates of capital input in current and constant prices are constructed for corporate business, non-corporate business, and households and non-profit institutions in the United States for the period 1929–1967. These estimates are prepared in a form suitable for integration into the U.S. National Income and Product Accounts.
440 citations
TL;DR: The streptomycin locus of E. coli specifies a 30S ribosomal protein which determines the sensitivity of the 30S subunit to strePTomycin and streptomecin induced errors of translation.
Abstract: The streptomycin locus of E. coli specifies a 30S ribosomal protein which determines the sensitivity of the 30S subunit to streptomycin and streptomycin induced errors of translation.
435 citations
TL;DR: Four axon types occur in the lateral geniculate nucleus and two contain vesicles with mainly round profiles and these are distinguished from each other by their size, the appearance of their contents and by the types of contact they make.
Abstract: Four axon types occur in the lateral geniculate nucleus. Two contain vesicles with mainly round profiles and these are distinguished from each other by their size, the appearance of their contents and by the types of contact they make. The larger “RLP” axons are interpreted as retinogeniculate and the smaller “RSD” axons as corticogeniculate fibers. The other two axon types contain many irregular or flattened vesicles and these “F” axons are regarded as two types of intrageniculate fiber. In laminae A and A 1 encapsulated synaptic zones form around grape-like dendritic appendages. These zones contain all axon types, but RSD axons are rare. Interstitial zones lie between the encapsulated zones and contain synapses formed by many RSD axons, some F and few RLP axons. The interstitial zones continue into the central interlaminar nucleus which forms a narrow band containing no encapsulated zones and few RLP axons. Lamina B contains relatively small RLP axons, very many RSD axons and only a few small encapsulated zones. Axosomatic junctions are rare throughout the nucleus. Axo-axonal junctions occur in all laminae but mostly in the encapsulated zones; the postsynaptic element is always an F axon, RLP or RSD axons generally form the presynaptic element.
431 citations
TL;DR: For the general case of jointly distributed random variables x and y, this paper derived the exact variance of the product xy and uv for the special case where y and x are stochastically independent.
Abstract: For the general case of jointly distributed random variables x and y, Goodman [3] derives the exact variance of the product xy. For the special case where x and y are stochastically independent, he provides a simpler expression for the exact variance. We offer a weaker set of assumptions which suffices to yield the simpler expression. We then extend Goodman's analysis to present the exact covariance of two products xy and uv, and sketch several specializations and applications.
426 citations
TL;DR: Electron microscopy of heteroduplex DNA molecules, composed of one strand of Escherichia coli phage λ+ DNA annealed to the complementary DNA strand of a λ deletion or substitution mutant, permits visualization, as well as precise measurements and mapping, of the unpaired single-stranded regions of nonhomology in the otherwise double- Stranded molecules.
Abstract: Electron microscopy of heteroduplex DNA molecules, composed of one strand of Escherichia coli phage λ+ DNA annealed to the complementary DNA strand of a λ deletion or substitution mutant, permits visualization, as well as precise measurements and mapping, of the unpaired single-stranded regions of nonhomology in the otherwise double-stranded molecules. In the λb2 mutant, the central segment (13 percent) of the λ+ DNA molecule is shown to be deleted. In the hybrid phages λi434 and λi21 a segment of the right arm of the λ+ genome (5.5 or 7.6 to 9 percent) is replaced by the corresponding immunity regions of phage 434 (3.3 percent or phage 21 (4 percent) DNA. The b5 region in the λb5 mutant appears to be identical to the i21 segment. From these data it is possible to estimate the size and posiion of those λ genes which are replaced by the i434 and i21 segments. The method permits preparing complete physical maps of viral genomes with a precision heretofore unattainable.
379 citations
TL;DR: These experiments show that when a rat encounters objects which deflect its mobile or stationary vibrissae, a relatively large population of first-order somatic sensory neurons is capable of coding the following aspects of mechanical stimuli: peripheral location, deflection direction, onset, termination, amplituded, velocity, duration, repetition rate, and temporal pattern.
353 citations
TL;DR: In this paper, the authors defined the minimum number s(G) s such that an arbitrary sequence of length s of group elements has a subsequence whose product is 1, for a finite Abelian group G.
TL;DR: In this paper, it is shown that increasing the complexity of requirements for a sequence to be accepted by a finite automaton raises the level in the Borel hierarchy at which definable sets are found.
Abstract: In [4], Hartmanis and Stearns investigated properties of sets of infinite sequences which can be defined by finite automata. In this paper we consider various definitions for machines of this type, including ones introduced by Biichi [1] and McNaughton [6]. For each type of finite automaton we classify the complexity of definable sets of sequences. More precisely, let y/o be the set of oJ-sequences on the finite set Y.. Consider the Borel hierarchy with respect to the product topology on E ~'. The complexity of a subset of E °' is given by its position in the Borel hierarchy. It is shown that increasing the complexity of requirements for a sequence to be accepted by a finite automaton raises the level in the Borel hierarchy at which definable sets are found. Furthermore, procedures are given for deciding the complexity of sets defined by a large class of machines. In [4], ~ is taken to be {0, 1} and the usual topology on the real line is considered. We use the product topology because it is more natural when dealing with finite-state machines, in that it avoids the necessity of identifying infinite sequences (e.g., 100.. . equals 011. . . on the real line). Moreover, the product space YY' is, in effect, an infinite tree with paths through the tree corresponding in a one-to-one fashion with points of y o,. We believe that this analogy adds an intuitive flavor to the proofs. The second section contains definitions and an outline of related results. Section 3 gives the hierarchy results. In Section 4 we give algorithms for deciding the complexity of sets defined by arbitrary machines. Relationships between the various machine types are also explored. In the last section we discuss reducibility relationships existing among various undecidable properties of Turing machines which accept infinite sequences.
TL;DR: It is proposed that the membrane surrounding cytoplasmic channels in the dividing nucleus may be involved in the separation of daughter chromosomes, which may resemble prokaryotes in the manner of genophores separation as well as in genophore chemistry and ultrastructure.
Abstract: Dinoflagellates are of interest because their chromosomes resemble the nucleoplasm of prokaryotes both chemically and ultrastructurally. We have studied nuclear division in the dinoflagellate Gyrodinium cohnii (Schiller), using cells obtained from cultures undergoing phasic growth. Electron micrographs of serial sections were used to prepare three-dimensional reconstructions of nuclei and chromosomes at various stages of nuclear division. During division, a complex process of invagination of the intact nuclear envelope takes place at one side of the nucleus and results in the formation of parallel cylindrical cytoplasmic channels through the nucleus. These invaginations contain bundles of microtubules, and each of the bundles comes to lie in the cytoplasm of a cylindrical channel. Nuclear constriction occurs perpendicular to these channels without displacement of the microtubules. There are no associations between chromosomes and the cytoplasmic microtubules. In dividing cells most chromosomes become V-shaped, and the apices of the V's make contact with the membrane surrounding cytoplasmic channels. It is proposed that the membrane surrounding cytoplasmic channels in the dividing nucleus may be involved in the separation of daughter chromosomes. Thus, dinoflagellates may resemble prokaryotes in the manner of genophore separation as well as in genophore chemistry and ultrastructure.
TL;DR: Segments of mature tobacco leaves were fixed in glutaraldehyde, incubated in medium containing 3,3'-diaminobenzidine (DAB) and hydrogen peroxide, and postfixed in osmium tetroxide to suggest that catalase is responsible for the reaction.
Abstract: Segments of mature tobacco leaves were fixed in glutaraldehyde, incubated in medium containing 3,3'-diaminobenzidine (DAB) and hydrogen peroxide, and postfixed in osmium tetroxide. Electron microscopic observation of treated tissues revealed pronounced deposition of a highly electron-opaque material in microbodies but not in other organelles. The coarsely granular reaction product is presumably osmium black formed by reaction of oxidized DAB with osmium tetroxide. Reaction of the microbodies with DAB was completely inhibited by 0.02 M 3-amino-1,2,4-triazole and was considerably reduced by 0.01 M potassium cyanide. These results, when considered in light of recent biochemical studies, strongly suggest that catalase is responsible for the reaction. Sharp localization of this enzyme in microbodies establishes that they are identical to the catalase-rich "peroxisomes" recently isolated from leaf cell homogenates. A browning reaction that occurred in leaves during the incubation step was inhibited by cyanide but not by aminotriazole and therefore could not have been caused by the same enzyme. This reaction and a slight deposition of dense material within primary and secondary walls are ascribed to oxidation of DAB by soluble and wall-localized peroxidases.
TL;DR: The kinetics of this refolding process under the conditions used has been shown to be almost identical to those of reconstitution of 30 s ribosomes from RNA and proteins, representing a structural rearrangement of RI particles which requires high activation energy.
TL;DR: The energy balance and the diffusion porometer measurements indicate that the boundary layer resistances of leaves in the field are substantially less than those predicted from heat transport formulas based on wind flow and leaf size.
Abstract: Modifications of the design and calibration procedure of a diffusion porometer permit determinations of stomatal resistance which agree well with results obtained by leaf energy balance. The energy balance and the diffusion porometer measurements indicate that the boundary layer resistances of leaves in the field are substantially less than those predicted from heat transport formulas based on wind flow and leaf size.
01 Jan 1969
TL;DR: The potential of mass spectrometers for the solution of structural problems has been recognized by the organic chemical community in general, and since then rather extensive and sophisticated use has been made of the technique for structural studies on organic compounds as discussed by the authors.
Abstract: Mass spectrometry does not represent a novel physical tool in geochemical research. Petroleum chemists have made use of mass spectrometry for many years in the analysis of the components of crude oil. Such applications were concerned primarily with quantitative analytical problems, with emphasis on the determination of compound types which constitute a given petroleum sample, and the number of papers on this subject is legion. In recent years — and the developments of recent years are primarily the subject of this review — the tremendous potential of mass spectrometry for the solution of structural problems has been recognized by the organic chemical community in general, and since then rather extensive and sophisticated use has been made of the technique for structural studies on organic compounds. The widespread application to problems of organic chemistry has in turn sparked intense interest in mechanistic studies on the fragmentation processes of ionized molecules in the vapor state. Practical applications and fundamental studies combined have thus within a few years produced a substantial body of information on the nature of mass spectra of organic compounds, information which makes feasible a fruitful exploitation of mass spectrometric data for the solution of structural problems. The considerable number of volumes [1–10] addressing themselves wholly or in part to the application of mass spectrometry to problems of organic and natural products chemistry reflects the pace of progress and the scope of this field; it is recommended that these works be consulted for a thorough initiation into all phases of organic mass spectrometric research and its ramifications.
TL;DR: Findings support the concept of the separate existence of cytochromes a and a3, and indicate that cytochrome a and the EPR-undetectable copper are titrated first, at which point ferricy tochrome a3 becomes detectable by EPR.
TL;DR: There is an excellent quantitative correlation between the carcinogenic activities of eight hydrocarbons and the transformation frequencies they produce in this system, and it has been shown that each of such piled‐up colonies gives rise to fibrosarcomas in mice.
Abstract: A quantitative system for producing malignant transformation of adult C3H mouse ventral prostate cells in culture with carcinogenic hydrocarbons has been developed. Aneuploid cell lines derived from mouse prostate are plated at a low density on a feeder layer and treated with various hydrocarbons for different lengths of time; other dishes are treated with 0.5% dimethyl sulfoxide (the solvent for the hydrocarbons) as controls. After 8 days some dishes are fixed and stained and the colonies are counted for total plating efficiency. Two weeks later other dishes are also fixed and stained. In the DMSO controls, the cells remain as a monolayer. In the carcinogen-treated dishes, piled-up multilayered colonies are seen and their frequency is scored. It has been shown that each of such piled-up colonies gives rise to fibrosarcomas in mice, whereas the cells obtained from the monolayer areas of treated dishes do not cause tumors. Thus, these piled-up colonies represent malignant transformation, under conditions where no spontaneous malignant transformation occurs. There is an excellent quantitative correlation between the carcinogenic activities of eight hydrocarbons and the transformation frequencies they produce in this system. Malignant transformation has been produced by treatment with methylcholanthrene for only one day. The acquisition of heat sensitivity is an early consequence of malignant transformation in this system.
TL;DR: In this article, the number of 4, 18 and 26 s RNA cistrons present in purified nuclear and mitochondrial DNA of Saccharomyces cerevisiae has been determined and the significance of these findings to the continuous synthesis of ribosomal RNA during the cell cycle of yeast is discussed.
TL;DR: The specific activities of glucose 6-phosphatase and DPNH-cytochrome c reductase were approximately 50% those found for the same enzymes in the cytoplasmic membrane, which strongly suggests that these activities are associated with only one of the leaflets of the nuclear membrane, presumably the outer.
TL;DR: In this article, a representation for the scattering amplitude that contains Regge behavior, crossing symmetry, and analyticity is discussed, and it is shown that it provides a different ghost-eliminating mechanism (the Mandelstam-Wang one) from that given by Veneziano's proposal.
Abstract: A representation for the scattering amplitude that contains Regge behavior, crossing symmetry, and analyticity is discussed. It is shown that it provides a different ghost-eliminating mechanism (the Mandelstam-Wang one) from that given by Veneziano's proposal. Furthermore, it does not restrict the external masses, but reduces to Veneziano's formula when $\ensuremath{\alpha}(s)+\ensuremath{\alpha}(t)+\ensuremath{\alpha}(u)$ equals a particular integer that depends on the reaction. Several examples are discussed. The behavior of the Regge residue ${\ensuremath{\beta}}_{\ensuremath{\rho}\ensuremath{\pi}\ensuremath{\pi}}(t)$ at ${\ensuremath{\alpha}}_{\ensuremath{\rho}}(t)=0$ is proposed as a test that distinguishes the two representations.
TL;DR: A question often posed by students of American state politics is: "Do state political systems leave a distinctive imprint on patterns of public policy?" Prior to recent years, the nearly automatic response of political scientists was an unqualified but increasingly confident "no" as mentioned in this paper.
Abstract: A question often posed by students of American state politics is: “Do state political systems leave a distinctive imprint on patterns of public policy?” Prior to recent years the nearly automatic response of political scientists was an unqualified “yes.” More recent research has led to a qualified but increasingly confident “no.”Several recent publications have explored relationships between various indices of state politics, socio-economic characteristics, and public policy. The general conclusion has been that central features of the political system such as electoral and institutional circumstances do not explain much of the variation in policy. There are occasionally high correlations between individual measures of voter turnout, party competitiveness, or the character of state legislatures and some aspects of governmental spending. But these political-policy correlations seem to disappear when the effect of socioeconomic development is controlled.These are disturbing findings. They have not gone unchallenged. But the challenges, rather than reassuring those who have asserted the relevance of parties, voting patterns, and government structures, have demonstrated that the burden of proof now rests on those who hypothesize a politics-policy relationship. The problem has not been resolved.Part of the problem may rest on the conceptualization and measurement of the central variables. Electoral balance or alternation in office is not “inter-party competition,” except in the most mechanical sense. Compare Massachusetts' loose-knit party structure to the centralization of Connecticut's. “Party competition” is not the same as “party organization.” And party competition, voting habits, and patterns of apportionment fall far short of being equivalents of “political systems.”
TL;DR: The data indicate that both phagocytosis and hydrogen peroxide stimulate rat leukocyte hexose monophosphate shunt activity, and similar effects of inhibitors on these two processes suggests that endogenously generated hydrogenperoxide may stimulate the direct oxidation of glucose in phagocrytizing cells.
TL;DR: A maize embryo having the nuclear constitution of a reduced gametophyte cell is produced in 3 percent of the embryo sacs of inbred strain Wisconsin-23 that carry the mutant indeterminate gametape (ig).
Abstract: A maize embryo having the nuclear constitution of a reduced gametophyte cell is produced in 3 percent of the embryo sacs of inbred strain Wisconsin-23 that carry the mutant indeterminate gametophyte (ig). The nucleus of most monoploid sporophytes so derived is paternal. Such androgenetic monoploids may originate from a sperm nucleus acting in conjunction with the cytoplasm of a maternal cell from which the nucleus has been functionally displaced.
TL;DR: Investigation of the metabolism of vitamin D3 to its biologically active form, 25-hydroxycholecalciferol, in perfused rat livers and in rat liver homogenates found significant conversion was observed, supporting earlier data which indicate that the liver is the major, if not the only, site of conversion of vitaminD3 to 25-HCC.
TL;DR: In this article, the authors derived quantum rate equations for semiconductor lasers (SL) in the high-temperature limit for pure and highly doped III-V compound semiconductors.
Abstract: Quantum-mechanical rate equations are derived for semiconductor lasers (SL). Fluctuation operators with shot-noise character describe the quantum nature of the transitions. These equations are treated in the high-temperature limit for pure and highly doped III-V compound semiconductors. Numerical calculations are carried out for GaAs. From the mean rate equations we determine (a) the temperature dependence of the threshold pump rate for pure bulk SL and the threshold current for SL junctions and (b) the temperature and pump dependences of the mean light intensity and of the mean quasi-Fermi-level. By linearizing the fluctuations around the mean values, the noise spectrum for the light intensity is obtained. The general form of the noise spectrum is the same as that obtained by McCumber for a four-level laser system. Above threshold a sharp resonance is found in the GHz region. The temperature and pump dependences of the spectrum and especially of the resonance frequency are calculated in detail. The results from the mean equations and from the noise calculations which are obtained for highly doped GaAs are compared with experimental results for junction lasers, and good agreement is found. For pure SL the present numerical results are in good agreement with former analytical results of Haug and Haken for the mean intensity and for the low-frequency part of the noise spectrum, which have been found for the regions below and above threshold. The results for pure bulk SL are applicable to experiments with optical or electron-beam excitation.