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The uptake of sulphate from a complete nutrient solution labelled with S35 by 12-day-old sunflower plants has been measured. a) During the first few minutes a rapid initial uptake by the roots took place which has been interpreted as diffusion and mass flow into an apparent tree space. During the following hours a slow uptake occurred at a constant rate in both roots and shoots. b) The retention of ions in the roots was independent of the transpiration intensity. The transport to the shoot could be represented by the line y = kx+l, were y = amount sulphate transported to the shoot and x = water transpired. A direct connection between ion and water transport could thus be demonstrated. c) At different medium concentrations (0.25, 0.5, 5, and 50 mM SO4) the value of k in the above-mentioned equation varied. The ratio k/medium concentration gives the influx coefficient, which is an expression for the concentration in the transpiration stream of the water linked component (kx) of the ions translocated to the shoot. The values of the influx coefficient varied between 0.54 and 0.11, the higher values being obtained at low external concentration. The possibilities of the action of active and passive ion transport mechanisms in these experiments and some new papers treating these problems are discussed. [ABSTRACT FROM AUTHOR]

Modulation of rat liver mitochondrial adenytate kinase by citric acid cycle intermediates is reported. Activation of adenylate kinase in the presence of Mg2+ was dependent upon the following. (1) It was activated by citrate, cis­aconitate, isocitrate, fumarate, and malate but not by 2-oxoglutarate, succinate, or oxaloacetate. (2) Protonated forms of the intermediates were most effective: (3) Citrate caused a decrease from 6,9 to 4.1 in the Km for ATP. (4) The activation was not a simple citrate-Mg2+ chelation phenomenom (5) The Ka for citrate was 90 μM. (6) Activation was very rapid. (7) Citrate caused a decrease from 2.1 to 1.3 in the slopes of Hill plots with increasing ATP. (8) Measurements in differential absorbaneies in the presence and absence of citrate and Mg2+ indicated structural changes in adenylate kinase upon modulator binding, (9) Non-additive effects of saturating concentrations of several citric acid cycle intermediates could be interpreted as a common binding site for each of the intermediates. It is postulated that the citrate modulation of adenylate kinase involves an alteration in the structure of the enzyme. [ABSTRACT FROM AUTHOR]

The potassium salts of methyl [35S] sulphate and butyl [35S] sulphate have been prepared and their ability, to migrate across selected human skin samples from aqueous, unbuffered solutions examined. By comparison to the results obtained with potassium dodecyl [35 S] sulphate in the previous paper, both the present sulphate esters are able to migrate across intact whole skin samples with the methyl ester exhibiting the higher order of migration. Application of the dodecyl ester and the butyl ester in dimethyl sulphoxide solutions did not alter the pattern of migration whereas the methyl ester showed a concentration dependant accelerant relationship with increasing concentrations of dimethyl sulphoxide. Limited studies on inorganic 35SO42- ions indicated that this substance did not migrate across whole skin samples from aqueous unbuffered solutions. The primary resistance barrier to the passage of each of the above test materials was absent when " stripped " skin samples were used as the diffusion-membranes. The implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

1. The primary response contributing to an overall inhibition of root growth by IAA is a concentration dependent shortening of the period over which the roots elongate. 2. Deformation of root cell walls under constant, externally imposed load is composed of a plastic and an elastic component. These components are separable under the usual conditions of mechanical analysis. 3. Treatment of intact roots for one hour in the presence of concentrations of IAA that normally promote shoot growth and, therefore, inhibit root growth, results in formation of a concentration dependent, IAA-induced plasticity component, not observable in untreated roots. The change in deformability may be indicative of specific wall components either synthesized or altered in the presence of IAA. 4. Half-maximal plasticity is induced by ca. 5 × 10-7 M of IAA, a concentration comparable to that for Avena coleoptiles. 5. Deformability induced by IAA-treatment is transient, reaching a maximum after approximately one hour. 6. That increased deformability may be associated with increased root growth is indicated by measurements of fresh weight changes of excised root sections in the presence and absence of IAA. The IAA-induced increase in fresh weight is also transient with a maximum after approximately one hour. The overall effect of IAA-treatment of root sections -is to reduce growth. 7. Ionic regulation of cell wall deformability is found to be similar to that reported for stem tissues. Addition of divalent calcium ions results in cell wall stiffening, an effect which is reversed in the presence of an excess of monovalent sodium or potassium ions. [ABSTRACT FROM AUTHOR]

Methods for preparing non-lytic alexinated intermediates that react with conglutinin are described for rabbit and human complements as well as equine. Certain properties of these intermediates including, particularly, their stability, are described. It has been found that, while such intermediates can be formed from the various complements, no single method works for all of them. Differences between 'haemolytic' and 'conglutinating' complements are believed to reflect quantitative differences in reaction kinetics and in relative proportions of various components rather than any qualitative differences in components or reaction sequence. By the use of the rabbit alexinated intermediate it has been possible to show autoreactivity of auto-stimulated rabbit immunoconglutinins.

Evidence has been advanced confirming earlier work that conglutinin reacts solely with a determinant exposed in fixed C'3a. The reactivity is not influenced by the decay of earlier components or the activity of later ones. Heterologous sources of C'33 (rabbit and human) reacting with guinea-pig EAC'142 give conglutinable intermediates. The stability of EAC'1423a1 for conglutination is much greater than for lysis. The study of decayed intermediates which still react with conglutinin suggests that the bulk of the C'3a fixed has after some time no haemolytic function. Possible explanations of this phenomenon are discussed. The 'long-term' functions of the bulk of the fixed C'3a may therefore be associated with manifestations of complement activities other than haemolysis.

A high precision differential absorption technique has been developed for the detailed experimental analysis of the complex melting behaviour of specific tRNAs. This technique allows the resolution of overlapping transitions which have been observed in a study of the interaction of Mg2+ ions with tRNAAla (yeast). On the basis of these experimental observations a strong coupling between two adjacent transitions in tRNAAla is proposed and discussed with respect to the structure of tRNAAla. The sedimentation coefficient of tRNAAla as a function of temperature up to 80° has been studied in detail. The wavelength dependences of the hyperchromicities of various transitions in tRNA and tRNA half molecules are discussed with regard to A · U and G · C pairs melting in these processes. From a comparison of the melting behaviour of tRNAAla, tRNATyr, tRNASer, and tRNAPhe in the presence and the absence of Mg2+ ions it is shown that tRNAAla is best suited for detailed studies of conformational changes in tRNA. [ABSTRACT FROM AUTHOR]

Cells of the ascomycete Ophiostoma multiannulattum became sensitive to inorganic salts after a heat shock or a treatment with 2,4-dinitrophenol. The induced sensitivity to chloride and bromide ions could be largely reversed by histidine and certain other imidazole derivatives. No other organic compounds tested except imidazoles possessed this ability. The sensitization is interpreted as a consequence of an injury to cellular membranes, in particular those of the mitochondria, and to an impaired oxidative phosphorylation. [ABSTRACT FROM AUTHOR]

Studies were conducted to determine cellular site of Ca action in promoting pollen growth of Crinum asiaticum and a few other species. The following experimental results have strongly indicated that Ca binding takes place in pectins of the pollen tube walls. This appeared to increase the wall rigidity and to regulate permeability of the pollen cells thereby enhancing pollen growth. Radioactive Ca incorporation was observed exclusively in the pollen tube wall regions. The promoting action of Ca on pollen growth disappeared when pectinase was supplemented to the media. This was not the case with cellulase and other enzymes used. Methyl donors promoted pollen growth, and the promotion was more than doubled if Ca ions were present. Ethionine, on the other hand, inhibited tube elongation and exhibited no Ca effect. Growth of pollen tubes in oscillated liquid media during elongation was poorer than growth in standing media. The Ca effect was also reduced when pollen was oscillated. The observations made of the reduced rate of 45Ca incorporation when pollen was washed in water, and the hydroxylamineferric chloride test, have indicated that a considerable portion of these pectins are cold-water soluble. [ABSTRACT FROM AUTHOR]

Retention of sodium ions from solutions pressed through excised bean (Phaseolus vulgaris L.) stems was investigated. When the ambient solution contained 1 μe sodium per ml the exudates was found to be almost completely depleted of sodium ions. The ratios of sodium concentration in ambient and exudated solutions decrease with increasing ambient concentration. Sodium retention in excised stems is decreased when metabolism is slowed down by anaerobiosis or inhibitors. It is concluded that sodium retention in the basal parts of bean plants is due to its active accumulation by cell lining its path to and in the vascular tissue. [ABSTRACT FROM AUTHOR]

Physiological studies of self incompatibility were made with Oenothera organensis. Techniques used included a relatively simplified method of semi-vitro or stylar culture of pollen. The presence of Ca ions at certain levels in either cultural medium or pre-soaked stylar sections partially overcame the incompatibility reaction. The Ca action is believed to be due to either protection of pollen cell walls from the incompatibility inhibition or increased cell wall rigidity which leads to the promotion of pollen tube growth. Therefore, the probable site of the incompatibility reaction is considered to be at the surface of the pollen tube wall. Better pollen growth was observed when a larger pollen population was introduced to the stigma. This is regarded as an increase in the quantity of available Ca for pollen growth. Either addition of Ca to the cultural media or the stylar sections for small populations of pollen resulted in considerable promotion of tube growth the incompatibility reaction was also partially overcome by either a cold temperature (5°C) during, or high temperature (50°C) prior to the growth period. It is assumed that the temperature effect is probably due to the inactivation of a certain protein, possibly enzymatic in nature, involved in the incompatibility reaction. [ABSTRACT FROM AUTHOR]

The germination of dormant rice seed is stimulated by nitrate, nitrite, and hydroxylamine, but only slightly or usually not at all by ammonium ions. Urea and a number of amino acids have no effect. Steeping the dormant seeds in solutions of low pH (2.0 or below) before the seeds are set to terminate in water stimulates germination. The pH of the steeping solution has no effect within the range pH 3.0 to 11.0. Steeping at pH 12.0 and above retards the breaking of dormancy. The pH of the medium in which the seeds are set to germinate has no effect on the percentage germination of a dormant population over the range 3.0 to 8.4 or a little above, but outside this range germination is inhibited. By the application of both nitrate and high concentrations of hydrogen ions in the steeping solution a number of dormant seeds are stimulated to germinate which otherwise would not have been affected by the nitrate or hydrogen ions alone. Cu++, Hg++, Ag++, and, to a lesser extent, MoO4-- ions retard the breaking of dormancy at concentrations which do not affect the percentage germination of populations which have completely broken dormancy. None of the other metal ions which have been tried (Na+, K+, Mg++, Mn++, Fe++, Fe+++, Co++, Ni++, Zn++) had any significant effect on percentage germination at concentrations up to 10-2 M. [ABSTRACT FROM AUTHOR]

One strain of thermophilic bacteria has been isolated from spoiled canned peas and identified as being closely reated to Bacillus stearothermophilus Donk. This strain, called 234A, has been used for some investigations of the influence of nitrate on the sporulation of this kind of bacteria. At the same time the effect of nitrite has been studied and finally some tests have been carried out in order to ascertain if ammonium ions (in the form of NH4CI) in some way would change the effect of nitrate. The results clearly show that nitrate, possibly after reduction to nitrite, has a stimulating effect on the sporulation of 234A, although the nature of this effect is still quite unknown. Control tests made with KCl and NaCl have shown that no stimulation is obtained with these salts, viz. with potassium or sodium ions. No depression of the positive effect of nitrate could be observed in the presence of NH4CI, viz. ammonium ions. The experiments and results must be looked upon as being only preliminary and qualitative although some quantitative relations seem to exist between the concentration of nitrate (or nitrite) in the medium and the percentage of spores formed. The greatest percentage of spores seems to be obtained at about 0.1 per cent of nitrate and at 0.01-0.05 per cent of nitrite. Further investigations are needed on the factors influencing the sporulation of bacteria, both thermophilic and mesophilic. [ABSTRACT FROM AUTHOR]

The «apparent free space» of wheat roots was determined by four independent methods, namely by 1) time differentiation of chloride retention in the root sap, 2) inhibition of the metabolic accumulation of chloride in the root cells by the use of 2,4-dinitrophenol. 3) measurement of the exodiffusion of mannitol from roots previously equilibrated in mannitol, and 4) measurement of the physical equilibration of labeled phosphate within the roots at 0° C. Methods 1 and 3 give a value of 24.5 per cent for the A. F.S., while methods 2 and 4 give a value of 33.5 per cent. The basis of each method is discussed, with a consideration of the assumptions made and the errors involved. In the discussion it is shown that root thickness may be a decisive factor in determining the magnitude of a the «apparent free space». Calculations indicate that the cell walls probably constitute the dominant «free space» in wheat roots. Current views on the ways in which plasma and cell wall structures influence the movement of ions are reviewed. [ABSTRACT FROM AUTHOR]

The author, one of the nation's leading authorities on the effects atmospheric contaminants have on textiles, discusses the identification and action of the leading air poMutants-sulfur oxides, oxides of nitrogen, ozone and particulates-and recounts the research that led not only to the development of intermediates to reduce gas fading but of entirely new dye structures and dyeing processes. [ABSTRACT FROM AUTHOR]