Non-photosynthetic Microorganisms Research Articles

Purification and properties of NADP-dependent non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase from the green alga Chlamydomonas reinhardtii

NADP-dependent non-phosphorylating D-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.9), previously described in higher plants, has been now found to be present in eukaryotic green algae, but in neither cyanobacteria nor non-photosynthetic microorganisms. The enzyme from the unicellular green alga Chlamydomonas reinhardtii, strain 6145c, has been purified to apparent electrophoretic homogeneity. The non-phosphorylating enzyme was effectively separated from the NADP-dependent phosphorylating D-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13) dye-ligand chromatography on Reactive Red-120 agarose. The purified enzyme exhibited an optimum pH in the 8.5–9.0 range and a specific activity of approx. 8 μmol·(mg protein) −1·min −1. The native protein was characterized as a homotetramer with a molecular weight of 190 000, a Stokes radius of 5.2 mn, and an isoelectric point of 6.9. From kinetic studies, K m-values of 9.8 and 51 μM were calculated for NADP and D-glyceraldehyde 3-phosphate, respectively, an absolute specificity for both substrates being observed. L-Glyceraldehyde 3-phosphate was a potent non-competitive inhibior ( K i, 48 μM). The reaction products NADPH and D-3-phosphoglycerate inhibited enzyme activity in a competitive manner with respect to NADP ( K i, 78 μM) and D-glyceraldehyde 3-phosphate ( K i, 1.2 mM), respectively. Thermal inactivation occurred above 45°C and was effectively prevented by either substrate. The presence of essential vicinal thiol groups is suggested by the inactivation produced by diamide, with D-glyceraldehyde 3-phosphate, but not NADP, behaving as a protective agent. The enzyme's possible physiological role in photosynthetic metabolism is discussed briefly.

Effect of light on nonphotosynthetic microorganisms. VI. Photochromogenicity in genera Micromonospora, Microbispora and Actinoplanes.

The effect of light on the pigmentation of various strains of Micromonospora, Microbispora and Actinoplanes was investigated. It was found that four of eight strains of Micromonospora, two of five strains of Microbispora and two of three strains of Actinoplanes were photochromogenic. These photochromogenic strains produced carotenoids by photoinduction. Biochemical studies on the mechanism of photochromogenicity in Micromonospora echinospora, Microbispora chromogenes and Actinoplanes philippinensis showed that photoinduced carotenoid synthesis in these strains consists of an initial temperature-independent photochemical reaction step and a series of dark metabolic reaction steps, which involve de novo protein synthesis.

Effect of light on nonphotosynthetic microorganisms. V. Genetic control of photoinduced carotenogenesis in Mycobacterium smegmatis.

Genetic control of carotenoid synthesis in Mycobacterium smegmatis (M. smegmatis), which produces carotenoids both photoinducibly and constitutively, was investigated in several strains of M. smegmatis by using a multi-polar conjugation system. The analysis of the recombinants revealed that the amount of carotenoids produced was strain specific, and the photoinduced and constitutive carotenoid syntheses were under the same genetic control. At least 3 genes participate in the genetic control of carotenoid synthesis in M. smegmatis. Constitutive carotenoid synthesis of M. smegmatis is a result of an incomplete repression of carotenoid gene.

Activity of the natural algicide, cyanobacterin, on eukaryotic microorganisms

Abstract The natural product cyanobacterin has been shown to be toxic to most cyanobacteria at a concentration of approx. 5 μM. We demonstrate here that cyanobacterin will also inhibit the growth of most eukaryotic algae at a similar concentration. Some algae, such asEuglena gracilis, are resistant because they are able to maintain themselves by heterotrophic nutrition. Others, such asChlamydomonas reinhardtii, can apparently induce a detoxification mechanism to maintain photosynthesis in the presence of low concentrations of the inhibitor. Non-photosynthetic microorganisms are not affected by cyanobacterin.

Activity of the natural algicide, cyanobacterin, on eukaryotic microorganisms

The natural product cyanobacterin has been shown to be toxic to most cyanobacteria at a concentration of approx. 5 μM. We demonstrate here that cyanobacterin will also inhibit the growth of most eukaryotic algae at a similar concentration. Some algae, such as Euglena gracilis, are resistant because they are able to maintain themselves by heterotrophic nutrition. Others, such as Chlamydomonas reinhardtii, can apparently induce a detoxification mechanism to maintain photosynthesis in the presence of low concentrations of the inhibitor. Non-photosynthetic microorganisms are not affected by cyanobacterin.

Measurement of in situ activities of nonphotosynthetic microorganisms in aquatic and terrestrial habitats.

INTRODUCTION ... .. .... .. ..... .. .. .. 321 AUTECOLOGy. .. ......... .. ....... 322 Techniques Used in Assessment of Autecological Activity .. .. .. 323 Applications of Techniques Used in Assessment of Autecological Activity ... .. .. 324 SyNECOLOGy.. ....... .... 329 Problems in Interpreting the Measurement . 329 Radioisotopic Methods .... .. .. 332 Measurement of Cell Division ... ........ ........ ... .. ...... ........ ....... 341 Comparisons Between Methods.. .... .... .... ... 343

Measurement of In Situ Activities of Nonphotosynthetic Microorganisms in Aquatic and Terrestrial Habitats

Measurement of In Situ Activities of Nonphotosynthetic Microorganisms in Aquatic and Terrestrial Habitats

Purification and properties of glutathione reductase from the cyanobacterium Anabaena sp. strain 7119.

An NADPH-glutathione reductase (EC 1.6.4.2) has been purified 6,000-fold to electrophoretic homogeneity from the filamentous cyanobacterium Anabaena sp. strain 7119. The purified enzyme exhibits a specific activity of 249 U/mg and is characterized by being a dimeric flavin adenine dinucleotide-containing protein with a ratio of absorbance at 280 nm to absorbance at 462 nm of 5.8, a native molecular weight of 104,000, a Stokes radius of 4.13 nm, and a pI of 4.02. The enzyme activity is inhibited by sulfhydryl reagents and heavy-metal ions, especially in the presence of NADPH, with oxidized glutathione behaving as a protective agent. As is the case with the same enzyme from other sources, the kinetic data are consistent with a branched mechanism. Nevertheless, the cyanobacterial enzyme presents three distinctive features with respect to that isolated from non-photosynthetic organisms: (i) absolute specificity for NADPH, (ii) an alkaline optimum pH value of ca. 9.0, and (iii) strong acidic character of the protein, as estimated by column chromatofocusing. The kinetic parameters are very similar to those found for the chloroplast enzyme, but the molecular weight is lower, being comparable to that of non-photosynthetic microorganisms. A protective function, analogous to that assigned to the chloroplast enzyme, is suggested.

Single-Cell Proteins

Both photosynthetic and nonphotosynthetic microorganisms, grown on various carbon and energy sources, are used in fermentation processes for the production of single-cell proteins. Commercial-scale production has been limited to two algal processes, one bacterial process, and several yeast and fungal processes. High capital and operating costs and the need for extensive nutritional and toxicological assessments have limited the development and commercialization of new processes. Any increase in commercial-scale production appears to be limited to those regions of the world where low-cost carbon and energy sources are available and conventional animal feedstuff proteins, such as soybean meal or fish meal, are in short supply.

Essais sur la dégradation de la chaîne latérale des stanols en C27 et C28 par des microorganismes marins

Two experiments have been performed in enriched seawater, to examine the fate of cholestanol or campestanol, using micro-organisms present in the mussel Mytilus edulis . In the first, the products, analysed by gas-liquid chromatography and mass spectrometry, contained a C 26 stanol (12% of the total sterols). However, this compound is different from the C 26 stanol earlier isolated from a marine sediment, and a new structure is proposed. In the culture using campestanol, 90% of the recovered sterols consist of a monounsaturated (in the side-chain) C 25 stanol. From the results of a micro-ozonization this may be a mixture of isomers from the elimination, through oxidative degradation, of carbon atoms 26 and 27. However, we did not succeed in demonstrating that under our conditions, bacteria or non-photosynthetic micro-organisms of the marine environment are able to produce the classical C 26 structure from a C 28 precursor of the campestanol type.

Microbial Protein Production

During the past decade, numerous processes have been developed for producing cells of microorganisms for use as protein sources in human food or animal feed. This paper will consider the raw materials and microbes suitable for producing single-cell proteins (SCP) and the factors affecting their use. The discussion will include photosynthetic and nonphotosynthetic microorganisms--algae, bacteria, actinomycetes, yeasts, molds, and higher fungi-and raw materials for growth such as hydrocarbons and petrochemicals; agricultural, industrial, and forest products; and food-processing wastes. The emphasis will be on the processes that have been operated on a pilot-plant or commercial scale.1

Solar Lake (Sinai). 3. Bacterial distribution and production1

The relations between photosynthetic and nonphotosynthetic (chemoorganotrophic and chemolithotrophic) microorganisms in Solar Lake were studied during the annual limnological cycle. Six different bacterial plates were observed during stratification by direct and viable bacterial counts, light and dark CO2 incorporation, chlorophyll a, protein, ATP, and ETS determinations. A maximal dark CO2 incorporation of 1,014 mg C m−3 d−1 may represent as much as 16,900 mg C m−3 d−1 of chemoorganotrophic bacterial production, on the assumption that these bacteria assimilate an average of 6% CO2 of their total carbon uptake. This calculated production is very high in comparison to the recorded photosynthetic maximum of 4,960 mg C m−3 d−1. The organic carbon needed for such a high chemoorganotrophic production may be supplied by the benthic cyanobacterial mats. Extremely high specific activities of ATP and ETS for the layer immediately above the thermocline indicate a very active bacterial plate at this layer.

Nitrogen assimilation by phytoplankton and other microorganisms in the surface waters of the central North Pacific Ocean

Assimilation rates of 15N-labelled ammonium, urea, and nitrate by plankton in the upper euphotic zone were measured in 2 summer, 2 winter, and 1 spring cruise in the central North Pacific Ocean. Average rates of ammonium plus urea assimilation could not be determined precisely, but were estimated to be 7 to 25 μg-at. N m-3 day-1. Indirect evidence suggested that non-photosynthetic microorganisms contributed to these rates. Nitrate assimilation was negligible in the upper waters considered in this report (above the chlorophyll maximum and the nutricline). Potential, nitrate-saturated rates were in the range 1 to 8 μg-at. N m-3 day-1. Seasonal comparison showed lowest rates of both carbon and nitrogen assimilation rates per chlorophyll a in winter.

Superoxide dismutases in photosynthetic organisms.

Although molecular oxygen is an effective electron acceptor, for most organisms oxygen is harmful unless they have a protective mechanism against oxygen toxicity. This is especially the case when the organisms are irradiated “by visible light at high intensity mainly due to photodynamic action of endogeneous pigments. For example, almost all of non-photosynthetic microorganisms are not able to survive under sun light.

Sulfate uptake as a measure of planktonic microbial production in freshwater ecosystems.

A method is needed by which biomass production resulting from non-photosynthetic micro-organisms in natural aquatic ecosystems can be included in microbial production measurements. Both laboratory cultures and field samples were used for examining the suitability of measuring sulfate uptake as a yardstick of microbial production. Sulfate uptake, using 35SO4, was com pared with 14CO2 uptake and it was found that sulfate uptake measures significantly more microbial production than does 14CO2 uptake. With further study, the use of sulfate uptake may become a very satisfactory method for better estimating the total planktonic microbial production under aerobic conditions.

Early Photoinduced Enzymes of Photoinduced Carotenogenesis in a Mycobacterium Species

Abstract Some nonphotosynthetic microorganisms synthesize carotenes in response to light. Previous experiments demonstrated that the enzymes necessary for the synthesis and metabolism of phytoene were photoinduced in a Mycobacterium sp. We now report that prephytoene pyrophosphate synthetase is also totally photoinduced. Geranylgeranyl pyrophosphate synthetase (prenyltransferase), which is present in dark-grown cells, is increased severalfold by photoinduction. The enzymes necessary for the synthesis of high molecular weight (C35 to C40) polyprenyl pyrophosphates and isopentenyl pyrophosphate isomerase were unaffected by photoinduction. This is the first report of the photoinduction of enzymes acting prior to prephytoene pyrophosphate. These enzymes are not restricted to carotene synthesis.

Photoregulated carotenoid biosynthesis in non-photosynthetic microorganisms.

Abstract

Major paraffin constituents of microbial cells with particular references to Chromatium sp.

1. Paraffins ofChromatium strain D were extracted and analysed on a gas chromatograph. The results were compared with similar analyses on nonphotosynthetic and photosynthetic micro-organisms. 2. Analyses of the results indicated two general trends. Non-photosynthetic bacteria and fungi contained alkanes in the range C16–36 with a peak at round C27–29. Green and blue-green algae, andChromatium strain D alkanes had peaks at C17 and C20. 3. Analyses of carbon preference indices showed that non-photosynthetic bacteria, fungi and Chromatium exhibited values about unity whereas green and blue-green algae tended to have a Codd predominance. 4. The patterns ofn-alkanes in Chromatium are discussed in relation to those of other micro-organisms.

Mechanism of Photoinduced Carotenoid Synthesis: INDUCTION OF CAROTENOID SYNTHESIS BY ANTIMYCIN A IN THE ABSENCE OF LIGHT IN MYCOBACTERIUM MARINUM

Abstract Mycobacterium marinum, like a number of nonphotosynthetic microorganisms, produces only traces of carotenoids when grown in the dark. On illumination, the dark grown bacteria synthesize substantial amounts of carotenoids de novo. This study shows that antimycin A can also induce the synthesis of carotenoids in M. marinum in the absence of light. The amounts of carotenoids synthesized are proportional to the amount of antimycin A added; for maximal carotenogenesis, a concentration of 37.5 µm is required. Antimycin A is 300 to 400% more effective than saturating amounts of light in the induction of carotenoid synthesis. The effects of light and antimycin A are additive. Chromatography of the carotenoid pigments reveals that the same polyenes are synthesized regardless of the means of induction—light alone, antimycin A in the dark, or antimycin A plus light. Evidence is presented that both light and antimycin A act by inducing protein synthesis (carotenogenic enzymes). In the antimycin A-induced system protein synthesis continues for more than 20 hours. In the light-induced system, on the other hand, protein synthesis continues for 4 hours and then stops. However, a second illumination at this time can lead to a resumption of protein synthesis. Inasmuch as the inductive effects of light and antimycin A are additive, it is concluded that the sites of action of light and antimycin A are different. Antimycin A may act either as an inducer for the synthesis of carotenogenic enzymes or by inactivating a repressor. Light may have an analogous role but at a different site; it may act either by photo-oxidizing a repressor or by producing a photo-oxidized metabolite which can act as an inducer for the synthesis of carotenogenic enzymes.

Closing an Ecological System Consisting of a Mammal, Algae, and Non-Photosynthetic Microorganisms

The use of mammals and plants in a closed ecological system for possible space use is a difficult but necessary task, and this is the subject of this paper. Dr. Golueke is Associate Research Biologist and Chief Microbiologist, Sanitary Engineering Research Laboratory, University of California Engineering Field Station, Richmond. Dr. Oswald is Associate Professor of Sanitary Engineering, College of Engineering, and Associate Professor of Public Health, School of Public Health, University of California, Berkeley.