Coacervate-like microspheres from lysine-rich proteinoid

Microspheres form isothermally from lysine-rich proteinoid when the ionic strength of the solution is increased with NaCl or other salts. Studies with different monovalent anions and with polymers of different amino acid composition indicate that charge neutralization and hydrophobic bonding contribute to microsphere formation. The particles also form in sea water, especially if heated or made slightly alkaline. The microspheres differ from those made from acidic proteinoid but resemble coacervate dtoplets in some ways (isothermal formation, limited stability, stabilization by quinone, uptake of dyes). Because the constituent lysine-rich proteinoid is of simulated prebiotic origin, the study is interpreted to add emphasis to and suggest an evolutionary continuity for coacervation phenomena.     

Compartmentalization in proteinoid microspheres

Proteinoid microspheres with stable internal compartments and internal structure are made from acidic proteinoid and basic proteinoid with calcium. The populations of microspheres are characterized by a wide diversity of structure. A model of primitive intracellular communication is suggested by the observed movement of internal particles between compartments of a multicompartmentalized unit. Differential response to pH change and to temperature change has been demonstrated within one population and suggests one mode of adaptive selection among primordial cell populations.     

The Effect of Storage in Various Gaseous Atmospheres on the Microflora of Lamb Chops Held at—1°C

The effect of different gaseous atmospheres on the development of the bacterial flora on lamb chops stored at –1°C was examined. The atmospheres were air, nitrogen, hydrogen, and mixtures of air + carbon dioxide, oxygen + nitrogen, oxygen + carbon dioxide, nitrogen + carbon dioxide and hydrogen + carbon dioxide (gas ratio = 80:20, v/v). Storage life of chops ranged from two weeks in air to eight weeks in oxygen-free atmospheres. At the end of storage life Microbacterium thermosphactum was present as a major constituent of the bacterial flora in all atmospheres. In oxygen + carbon dioxide it was the predominant organism. In all other oxygen containing atmospheres, Pseudomonas spp. made up a large proportion of the flora. Strains of Enterobacteriaceae occurred in low-oxygen and oxygen-free atmospheres, and Lactobacillus spp. occurred in oxygen-free atmospheres.     

A model for the origin of stable protocells in a primitive alkaline ocean

When a mixture of the eighteen proteinous amino acids are suitably heated in the dry state with seawater salts, a copolyamino acid results. One fraction of this polymer is found, through isoelectric focusing, to consist of a mixture of acidic and basic proteinoids, each of sharply limited heterogeneity. When one fraction of the seawater proteinoid is dissolved in hot water, and the solution is cooled, proteinoid microspheres result. These have properties in common with simpler types, but are also stable at pH values to 9, in common with microspheres prepared by mixing acidic and basic proteinoids. These processes thus constitute a simple model for the origin of a protocell stable in a primitive alkaline ocean.     

Carbon dioxide injection method for enhancing hydrogenotrophic denitrification of secondary wastewater effluent in fixed bed reactor

This study presents an optimal injection method for using carbon dioxide as a carbon source for the hydrogenotrophic denitrification of secondary wastewater effluent in a laboratory-scale fixed bed reactor (FBR). The FBR was operated under three conditions: a continuous CO₂ supply, periodic CO₂ supply, and without a CO₂ supply. The continuous operation of the FBR without carbon dioxide injection resulted in an increase in pH to 10 and a noticeable level of nitrite accumulation. The continuous co-injection of carbon dioxide and hydrogen gas decreased the pH to a range of 6 ～ 8, but the denitrification efficiency decreased to 29%. The co-injection of carbon dioxide decreased the maximum dissolved hydrogen concentration and hydrogen mass transfer rate by 25 and 61%, respectively. Compared to the continuous injection method, a periodic injection of carbon dioxide increased the denitrification efficiency from 28.6 to 85% as the hydrogen flow rate and hydraulic retention time (HRT) increased. With the periodic injection of carbon dioxide, the nitrite accumulation appeared to be insignificant as the hydrogen flow rate increased.     

Contribution to the Chemistry of Plasma-Activated Water

Plasma-activated water (PAW) was prepared by exposure to nonthermal plasma produced by a positive dc corona discharge in a transient spark regime. The activation of water was performed in atmosphere of various surrounding gases (air, nitrogen, carbon dioxide, and argon). This PAW retains its biological activity, measured on the mouse neuroblastoma cells culture, even after storage for more than one year. The highest hydrogen peroxide content was found for PAWs prepared in the atmospheres of argon or carbon dioxide, whereas the PAWs prepared in air and nitrogen exhibited lower hydrogen peroxide content. The acidity of PAWs mediated by nitric and nitrous acid formation displayed an opposite trend. It is concluded that the long-lasting biological effect of PAW is mediated by hydrogen peroxide in acid milieu only, whereas other possible active components decompose rapidly.     

From proteinoid microsphere to contemporary cell: Formation of internucleotide and peptide bonds by proteinoid particles

Proteinoid microspheres of appropriate sorts promote the conversion of ATP to adenine dinucleotide and adenine trinucleotide. Other microparticles composed of basic proteinoid and enzymically synthesized poly A cause the conversion of ATP and phenylalanine to various peptides of phenylalanine. When viewed in a context with the origin and properties of proteinoid microspheres, these results model the origin from a protocell of a more contemporary type of cell able to synthesize its own polyamino acids and polynucleotides. Related earlier experiments explain in part the origin of the genetic code and mechanism.     

The mode of action of insecticidal controlled atmospheres

Arthropods cope with reduced oxygen and elevated carbon dioxide atmospheres with a reduction in metabolic rate, also called metabolic arrest. The reduction in metabolism lessens the pressure on the organism to initiate anaerobic metabolism, but also leads to a reduction in ATP production. The natural permeability of cellular membranes appears to be important for the survival of the arthropod under low oxygen or high carbon dioxide atmospheres. Despite the similarities in response, arthropod mortality is generally greater in response to high carbon dioxide as apposed to low oxygen atmospheres. There appears to be a greater decrease in ATP and energy charge in arthropods exposed to high carbon dioxide as compared with low oxygen atmospheres, and this may be due to greater membrane permeability under carbon dioxide leading to an inefficient production of ATP. Reduced oxygen and elevated carbon dioxide atmospheres can have an additive effect in some cases, depending on the concentrations used. The effect of these atmospheres on arthropods depends also on temperature, species and life stage. Additional work is needed to fully understand the mode of action of controlled atmospheres on arthropod pests.     

Formation of peptides from amino acids by single or multiple additions of ATP to suspensions of nucleoproteinoid microparticles

When lysine-rich proteinoid, which catalyzes the formation of peptides from amino acids and ATP, is complexed with acidic proteinoid to form microspheres of mixed constitution, the normal synthesis by basic proteinoid alone is multiplied several-fold. The product consists not only of small peptides but also of a high-molecular-weight fraction of substituted proteinoid.Suspensions of particles of lysine-rich proteinoid complexed with polyadenylic acid catalyze the synthesis of peptides from each of the amino acids tested with ATP. When equimolar solutions of mixtures of glycine and phenylalanine with ATP are tested in suspensions of complexes of lysine-rich proteinoid and each of various polyribonucleotides, both homopeptides and heteropeptides are produced. Glycylphenylalanine or phenylalanylglycine is the principal product; the preference is related to which polyribonucleotide is in the complex.The rate of conversion of amino acid to peptide is a function of whether ATP is added in a single batch or in repeated amounts adding to the same amount as in the single batch. Related experiments indicate a relatively rapid initial rate of decay of ATP in this system. These results are discussed relative to the mechanisms for continuous generation in modern organisms, as are the results in peptide formation.     

Thermal polymerization of amino acids under various atmospheres or at low pressures

The kinds and proportions of amino acids formed in two simulated prebiotic experiments or detected in hydrolyzed extracts of three extraterrestrial samples were found to polymerize thermally under various atmospheres or at low pressures. Yields, tested properties, and amino acid compositions of the polymers were not influenced by the type of enveloping atmosphere, including two simulated prebiotic atmospheres and five pure gases. However, polyamino acids prepared at low pressure (0.02, 10^?4 atm) were obtained in appreciably greater yield than those synthesized at 1 atm; amino acid composition was somewhat influenced by low pressure. The results indicate that polyamino acids could have been formed thermally under a variety of possible prebiotic atmospheres and on planetary bodies of low atmospheric pressure.     

Proteinoid microspheres more stable in hot than in cold water

The occurrence of organisms of primitive appearance near submarine hydrothermal vents has indicated sea-floor conditions that are like those under which proteinoid microspheres are produced in the laboratory. Experimental examination of the question of whether some proteinoid microspheres might be stable in hot water has revealed proteinoids that are soluble in cold water but precipitate on heating. Unanswered questions are discussed.     

Assembly of microspheres from acidic proteinoids and histones or histone-like proteinoids

Basic polyamino acids, whether organismic or synthetic in origin, alter the morphology of proteinoid microspheres in which they are included. The particles obtained with histone are essentially indistirguishable under the light microscope from those obtained with proteinoids of histone-like composition (histonoids). In each instance, structures of morphological complexity similar to those of some microfossils are obtained.     

Photoproduction of Hydrogen by the Marine Heterocystous Cyanobacterium Anabaena Species TU37-1 Under a Nitrogen Atmosphere

Hydrogen production rates by Anabaena sp. strain TU37-1 obtained after an initial 1-day incubation period were approximately 70 to 80 and 3 to 9 µmol (mg chl)^–1 h^–1 under argon and nitrogen atmospheres, respectively. Hydrogen production under argon was not enhanced by addition of carbon dioxide, but was enhanced to some extent under nitrogen by increasing the initial carbon dioxide concentration. Rates of hydrogen and oxygen production during the initial 7-hour period were 15 and 220 µmol (mg chl)^–1 h^–1, respectively, in vessels with 18.5% initial carbon dioxide. Hydrogen production under nitrogen was enhanced by addition of carbon monoxide (1%). The rate obtained from the initial 1-day incubation period was about 40 µmol (mg chl)^–1 h^–1, which corresponded to about 60% of that under argon. On the basis of these observations, a possible strategy for hydrogen production by nitrogen-fixing cyanobacteria under nitrogen in the presence of carbon monoxide is indicated.     

Effect of modified atmosphere composition on the metabolism of glucose by Brochothrix thermosphacta

The influence of atmosphere composition on the metabolism of Brochothrix thermosphacta was studied by analyzing the consumption of glucose and the production of ethanol, acetic and lactic acids, acetaldehyde, and diacetyl-acetoin under atmospheres containing different combinations of carbon dioxide and oxygen. When glucose was metabolized under oxygen-free atmospheres, lactic acid was one of the main end products, while under atmospheres rich in oxygen mainly acetoin-diacetyl was produced. The proportions of the total consumed glucose used for the production of acetoin (aerobic metabolism) and lactic acid (anaerobic metabolism) were used to decide whether aerobic or anaerobic metabolism predominated at a given atmosphere composition. The boundary conditions between dominantly anaerobic and aerobic metabolisms were determined by logistic regression. The metabolism of glucose by B. thermosphacta was influenced not only by the oxygen content of the atmosphere but also by the carbon dioxide content. At high CO(2) percentages, glucose metabolism remained anaerobic under greater oxygen contents.     

Influence of Acidic pH on Hydrogen and Acetate Production by an Electrosynthetic Microbiome

Production of hydrogen and organic compounds by an electrosynthetic microbiome using electrodes and carbon dioxide as sole electron donor and carbon source, respectively, was examined after exposure to acidic pH (∼5). Hydrogen production by biocathodes poised at −600 mV vs. SHE increased>100-fold and acetate production ceased at acidic pH, but ∼5–15 mM (catholyte volume)/day acetate and>1,000 mM/day hydrogen were attained at pH ∼6.5 following repeated exposure to acidic pH. Cyclic voltammetry revealed a 250 mV decrease in hydrogen overpotential and a maximum current density of 12.2 mA/cm² at −765 mV (0.065 mA/cm² sterile control at −800 mV) by the Acetobacterium-dominated community. Supplying −800 mV to the microbiome after repeated exposure to acidic pH resulted in up to 2.6 kg/m³/day hydrogen (≈2.6 gallons gasoline equivalent), 0.7 kg/m³/day formate, and 3.1 kg/m³/day acetate ( = 4.7 kg CO₂ captured).     

Is Helicobacter pylori a True Microaerophile?

BACKGROUND: There is no general consensus about the specific oxygen and carbon dioxide requirements of the human pathogen Helicobacter pylori. This bacterium is considered a microaerophile and consequently, it is grown under atmospheres at oxygen tensions 5-19% and carbon dioxide tensions 5-10%, both for clinical and basic and applied research purposes. The current study compared the growth of H. pylori in vitro, under various gas atmospheres, and determined some specific changes in the physiology of bacteria grown under different oxygen partial pressures. METHODS: Measurements of bacterial growth under various conditions were carried out employing classical solid and liquid culture techniques. Enzymatic activities were measured using spectrophotometric assays. RESULTS: H. pylori and all the other Helicobacter spp. tested had an absolute requirement for elevated carbon dioxide concentrations in the growth atmosphere. In contrast with other Helicobacter spp., H. pylori can tolerate elevated oxygen tensions when grown at high bacterial concentrations. Under 5% CO(2), the bacterium showed similar growth in liquid cultures under oxygen tensions from microaerobic (< 5%) to fully aerobic (21%) at cell densities higher than 5 x 10(5) cfu/ml for media supplemented with horse serum and 5 x 10(7) cfu/ml for media supplemented with beta-cyclodextrin. Evidence that changes occurred in the physiology of H. pylori was obtained by comparing the activities of ferredoxin:NADH (nicotinamide adenine dinucleotide) oxidoreductases of bacteria grown under microaerobic and aerobic atmospheres. CONCLUSIONS: H. pylori is a capnophile able to grow equally well in vitro under microaerobic or aerobic conditions at high bacterial concentrations, and behaved like oxygen-sensitive microaerophiles at low cell densities. Some characteristics of H. pylori cells grown in vitro under microaerobic conditions appeared to mimic better the physiology of organisms grown in their natural niche in the human stomach.     

Activation of glycine by ATP,a divalent cation,and proteinoid microspheres

The activation of glycine to yield glycyl hydroxamate has been studied in the absence of enzymes. Activation with ATP in aqueous solution requires only a divalent metal cation. ATP is far more active than other nucleoside triphosphates; AMP and pyrophosphate are inactive. The pH optimum is 4 to 5; activation at pH 7 is most enhanced in the presence of proteinoid microspheres.     

Effect of Modified Atmosphere Composition on the Metabolism of Glucose by Brochothrix thermosphacta

The influence of atmosphere composition on the metabolism of Brochothrix thermosphacta was studied by analyzing the consumption of glucose and the production of ethanol, acetic and lactic acids, acetaldehyde, and diacetyl-acetoin under atmospheres containing different combinations of carbon dioxide and oxygen. When glucose was metabolized under oxygen-free atmospheres, lactic acid was one of the main end products, while under atmospheres rich in oxygen mainly acetoin-diacetyl was produced. The proportions of the total consumed glucose used for the production of acetoin (aerobic metabolism) and lactic acid (anaerobic metabolism) were used to decide whether aerobic or anaerobic metabolism predominated at a given atmosphere composition. The boundary conditions between dominantly anaerobic and aerobic metabolisms were determined by logistic regression. The metabolism of glucose by B. thermosphacta was influenced not only by the oxygen content of the atmosphere but also by the carbon dioxide content. At high CO₂ percentages, glucose metabolism remained anaerobic under greater oxygen contents.     

Development of Haemonchus contortus in vitro and the stimulus from the host.

Infective larvae of Haemonchus contortus which have been exposed for about 9 hr to relatively high partial pressures of carbon dioxide at near-neutral pH, as they might be in the rumen, develop slowly to the fourth stage or not at all. But following this treatment, exposure to lower partial pressures of carbon dioxide and higher concentrations of hydrogen ions, such as might be encountered in the abomasal mucosa, brings about development at a rate comparable with that in the sheep.     

Proteinoids as complexes of polyamino acids with melanoidins

Proteinoids have been demonstrated as complexes of amino acid polymers with melanoidin pigments. Some physico-chemical properties of proteinoid pigments were studied in comparison with the standard melanoidins. Proteinoid pigments were able to enhance oxidoreduction and hydrolysis reactions, and their activity was comparable with the activity of the corresponding polyamino acid components or even of the entire proteinoids. The pigmented proteinoids had relatively strong ESR signal indicating the presence of free radicals into melanoidin components. Hypothetical participation of proteinoid melanoidin pigments in prebiotic evolution is discussed.