Non-biological Processes Research Articles

An ultrastructural study of iron and manganese deposition associated with extracellular polymers of pedomicrobium-like budding bacteria

Morphological characteristics of two Pedomicrobium-like budding bacteria are described. A structured surface layer was regularly observed on strain 868. Ruthenium red- and Alcian blue-staining polymers were found on both strains. When either strain was grown in the presence of iron or manganese, the corresponding oxides accumulated on their surfaces. In thin sections iron oxides appeared as fine threads, arrays of particles or dense coatings, depending on the source of iron. Manganese oxides appeared as branching filaments or convoluted ribbons. Both metal oxides stained with ruthenium red. Extraction of the oxides followed by ruthenium red staining revealed that polyanionic polymers previously deposited on the cells were associated with the metals. Treatment of cultures with glutaraldehyde, HgCl2, or heat, inhibited manganese but not iron deposition, suggesting that iron oxides accumulated by passive, non-biological processes. Manganese oxides apparently accumulated under control of a biological manganese-oxidizing factor. Incomplete inhibition of manganese deposition observed in cell suspensions suggested that, if the oxidizing factor was an enzyme, it was unusually stable. Based on these results, possible mechanisms of iron and manganese deposition in association with extracellular polymers are suggested.

The effects of culture concentration and age, time, and temperature on bacterial attachment to polystyrene

The attachment of a marine pseudomonad to polystyrene was found to be dependent upon (a) culture concentration, (b) the time allowed for attachment, (c) the growth phase of the culture, and (d) temperature. The number of attached cells increased with both culture concentration and the time allowed for attachment, until the attachment surface approached saturation. The number of cells which attached and the rate of attachment was greatest with log-phase cultures, and progressively decreased with stationary and death-phase cultures. A temperature of 3 °C ± 1 noticeably decreased the proportion of stationary phase cells which attached, compared with cells at 20 °C ± 1. These results can be described by a model based on physicochemical adsorption, which suggests that non-biological processes may play a major role in the initial events of bacterial adhesion.

Disappearance ofs-Triazines as Affected by Soil pH Using a Balance-Sheet Approach

The effect of soil pH on the disappearance of14C ring-labeled atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], hydroxyatrazine [2-hydroxy-4-(ethylamino)-6-(isopropylamino)-s-triazine], and prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] were studied over a 5-month period in a Bladen silt loam soil under greenhouse conditions. Employment of an integrated system allowed simultaneous monitoring of degradation, volatilization, respiration, plant uptake, and leaching processes. A resulting balance-sheet indicated that a range of 87 to 99% of the14C added could be accounted for after 5 months. Degradation was found to be the primary mode of dissipation. The pattern of atrazine degradation was characteristic of nonbiological processes, while prometryne degradation was probably by microbial action. Hydroxyatrazine was the major metabolite from the atrazine treatments while prometryne yielded an unknown and hydroxypropazine [2-hydroxy-4,6-bis(isopropylamino)-s-triazine]. Ex-tractable atrazine after 5 months amounted to 35% of the initial amount added in the pH 7.5 soil and 11% in the pH 5.5 soil, while prometryne occurred as 10% in the pH 7.5 soil and 42% in the pH 5.5 soil. Plant uptake and leaching occurred to a greater extent in the more alkaline soil with each chemical, but these pathways along with volatilization and respiration were minor contributors toward the disappearance of these herbicides.

The dynamics of life: aging.

Biologic aging arises from various causes, including deterioration of cells by mutations, destruction of the cells in organs through infections, aging by failure to eliminate harmful waste products, poisoning from external sources, and by radiation damage. All of these processes lead to equations of the kind observed experimentally for the aging process, so that a proper assessment of the various factors contributing to aging is especially complicated. Many nonbiological processes in which the products of reaction speed up the aging reaction lead to the familiar equation for the rate of aging. Corrosion of metals is exhibited as a typical example of this; many other examples could be given. The general equation for depth of anesthesia brought about by lipid-soluble materials and how this effect can be mimicked by accumulation of waste products is shown to simulate the typical aging curve; it is well known that such waste products are a frequent cause of death.

Measurement of 14CO2 Assimilation in Soils: an Experiment for the Biological Exploration of Mars

A method is described for the measurement of CO(2) assimilation by microorganisms in soils. A determination involves exposing soil to CO(2), pyrolyzing the exposed soil, trapping the organic pyrolysis products on a column of firebrick coated with CuO, combusting the trapped organics by heating, and measuring the radioactivity in the CO(2) produced in the combustion. The detection of significant levels of C in the trapped organic fraction appears to be an unambiguous indication of biological activity. The CO(2) which is adsorbed or exchanged into soils by nonbiological processes does not interfere. The method easily detects the CO(2) fixed by 10 to 10 algae after light exposure for 3 to 24 hr. Assimilation of C is also demonstrable in dark-exposed soils containing 10 to 10 heterotrophic bacteria. Possible applications of the method in the biological exploration of Mars are discussed.

Measurement of 14 CO 2 Assimilation in Soils: an Experiment for the Biological Exploration of Mars

A method is described for the measurement of 14 CO 2 assimilation by microorganisms in soils. A determination involves exposing soil to 14 CO 2 , pyrolyzing the exposed soil, trapping the organic pyrolysis products on a column of firebrick coated with CuO, combusting the trapped organics by heating, and measuring the radioactivity in the CO 2 produced in the combustion. The detection of significant levels of 14 C in the trapped organic fraction appears to be an unambiguous indication of biological activity. The 14 CO 2 which is adsorbed or exchanged into soils by nonbiological processes does not interfere. The method easily detects the 14 CO 2 fixed by 10 2 to 10 3 algae after light exposure for 3 to 24 hr. Assimilation of 14 C is also demonstrable in dark-exposed soils containing 10 5 to 10 6 heterotrophic bacteria. Possible applications of the method in the biological exploration of Mars are discussed.

The fate of hydroxyatrazine in a soil and a lake sediment

Ring 14C labelled hydroxyatrazine was incubated at room temperature with electron beam irradiated soil under aerobic and anaerobic conditions and in the presence or absence of a non-irradiated soil inoculum. Similar incubation experiments were conducted on a nonirradiated suspension of a lake sediment. A soil incubation at 99°C was also included. Evolution of 14CO 2 indicated that ring cleavage occurred at room temperature for all treatments except that of the uninoculated soil under anaerobic conditions. After 8–12 weeks, the residual hydroxyatrazine and degradation products were extracted with a series of solvents. The extracts were shown chromatographically to contain 14C labelled components other than hydroxyatrazine. No basic compounds were found and it is believed that a portion of the derivatives were compounds which had undergone modification of the ring substituents. Both aerobic and anaerobic species of microorganisms appear to be capable of metabolizing the hydroxyatrazine ring and non-biological chemical processes play no part in these transformations. Circumstantial evidence indicated that little or no chemical incorporation occurred between hydroxyatrazine or its derivatives and indigenous soil organic components.

STUDIES ON THE DISTRIBUTION OF COBALT IN LAKES

Cobalt‐57 was added to bottles of lake water to see whether there were any seasonal changes in the apportionment of cobalt between solution (filtrate) and seston after 24‐hr incubation or whether any differences in this distribution could be found between lakes.Several distinct patterns in the seasonal apportionment of 57Co between “solution” and seston were observed, but no explanation of the basic mechanism causing these changes is offered. In two of the lakes there was a statistically significant relation between certain detrital particles, rhizopods, and the per cent of introduced 57Co associated with solids.In general, direct biological uptake did not appear to be significant in removing 57Co from solution in Lake Mendota’s epilimnion. Photosynthetic activity was of little influence. Experiments with inhibitors and heated water also indicated that nonbiological processes were most important. Autoradiographs showed little radioactivity associated with algae.

On the depth, time and mechanism of petroleum generation

The subsurface petroleum generation process has been studied. In the Los Angeles and Ventura basins, California, hydrocarbon content and hydrocarbon/noncarbonate carbon ratio increase slowly with depth and age in upper and lower Pliocene shales and more rapidly in the deeper and warmer upper Miocene shales. During the oil generation process, and simultaneous with the increase of the hydrocarbon/noncarbonate carbon ratio, the composition of the shale normal paraffins and naphthenes boiling above 325°C gradually changes and eventually becomes very similar to that of the waxy oils of the basin. In the Los Angeles basin as well as in the Ventura basin the bulk of petroleum is generated at depths where the subsurface temperature is above 115°C and where, therefore, the shales are sterile. The conclusion that petroleum is formed from sediment organic matter essentially by thermal, nonbiological processes is inescapable. Because petroleum generation is a chemical process, it is strongly temperature-dependent. This explains the strong increase of the hydrocarbon/noncarbonate carbon ratio at greater depths, where the temperature is higher. It also explains the greater depth of oil generation and of equality of shale and oil hydrocarbon composition in the Ventura basin compared with the Los Angeles basin. This is caused by the smaller temperature gradient in the Ventura basin. The importance of the temperature history of potential oil source rocks is discussed. Appreciable amounts of oil are formed only if the temperature history of the source sediments is sufficiently intense and if the nature and the amount of the organic source material are appropriate. In the Los Angeles and Ventura basins most producing horizons are much shallower than the oil source beds, and vertical migration of petroleum is very common. Evidence is presented that vertical migration of petroleum takes place through faults and fractures, not through the bulk of the shales.

Nitrite Transformations in California Soils

AbstractIncubation studies of factors influencing nitrite oxidation in four California soils were conducted at two temperatures—45° and 75° F. In acid soils nitrite transformations were found to be highly sensitive to nitrite concentration in the soil and were inhibited by very low levels. Nitrite had less effect on the second step of nitrification in alkaline soils. Nitrite oxidizers were shown to be very sensitive to low temperature soil conditions.Although nitrite disappeared rapidly following addition to acid soils, little nitrate was produced during the incubation period. Much of the nitrite‐nitrogen was lost from the system. Experiments using acid soils which had been sterilized showed similar losses in added nitrite‐nitrogen and lead to the conclusion that these losses result from nonbiological processes. Studies to determine the nature of these losses suggest nitrogen gas as the principal product.Investigations of respiration rates of the soil population where various concentrations of nitrite were added reveal that nitrites inhibit the respiratory activity of the soil microorganisms as a whole and not merely the nitrifying group. Very low concentrations were inhibitory in acid soils; however, in a calcareous soil more than a hundred‐fold increase in nitrite concentration was required to achieve the same magnitude of respiratory inhibition.

The properties and theory of genesis of the carbonaceous complex within the cold bokevelt meteorite

The carbonaceous substances within the Cold Bokevelt Meteorite and other similar types of stones show uniform distribution. The Cold Bokevelt carbonaceous stone proved to contain over 1% extractable organic substances. The results of analyses, de-ashing experiments, etc., indicate that in addition the stone may bear a considerably higher proportion of carbonaceous matter. The extracts consist mainly of complex organic acids, they contain some organic chlorine, an element which has not been so far detected within any of the terrestrial bitumens. The fact that the extracts are optically neutral indicates that the organic matter may have been condensed from the atmosphere of the parent body through non-biological processes of polymerisation, etc. The low decomposition temperature of the finely divided carbonaceous substances seems to point to the hypothesis that the meteorite in question must have condensed under low-temperature conditions.