Managanese oxidation by Sphaerotilus discophorus

Johnson, A. H. (Washington State University, Pullman), and J. L. Stokes. Manganese oxidation by Sphaerotilus discophorus. J. Bacteriol. 91:1543-1547. 1966.-Cell suspensions of Sphaerotilus discophorus in 0.02 m potassium phosphate buffer (pH 7.2) readily oxidized MnSO(4) to dark-brown manganic oxide. The latter appeared to be MnO(2), since its color was the same as MnO(2) and, like the latter, it was readily soluble in HCl with the evolution of chlorine. The amount of O(2) consumed in the oxidation of Mn(++) was 63% or more of theoretical. The ability of the cells to oxidize Mn(++) was destroyed by heating the cells at 93 C for 5 min. Only cell suspensions prepared from cultures of S. discophorus grown with MnSO(4) were able to oxidize Mn(++). It was concluded that the oxidation of manganous ions by S. discophorus is catalyzed by an inducible enzyme(s).     

Deoxyribonucleic acid base composition of simonsiellaceae

The molar percentages of guanine plus cytosine in the DNA of 51 strains of Simonsiellaceae were determined by buoyant density ultracentrifugation of cell lysates in CsCl. The DNA base ratios ranged from 41–55 mole-% guanine plus cytosine. These values fall within the range known for the Order Cytophagales, the non-fruiting gliding bacteria, and are out-side the range of the Order Myxobacterales, the fruiting myxobacteria. Among the strains of the genus Simonsiella, four distinct groups can be delineated on the basis of source of origin (sheep, dog, cat, human) and GC content. The neotype of Alysiella filiformis has a GC content of 45.4 mole-%.     

Deoxyribonucleic acid base composition ofMicrococcus roseus

The percentage guanine + cytosine (GC) in the DNA of 13 strains ofMicrococcus roseus has been determined. Two methods were used to analyse the base composition, namely determination of T _m value and determination of the ratio E₂₆₀/E₂₈₀ at pH 3. The percentage GC in the strains ofM. roseus ranged from 66.2 to 73.8 and was in agreement with their present taxonomic position.     

Deoxyribonucleic acid base composition of Sporosarcina ureae

Summary The guanine + cytosine (GC) content of the DNAs of 11 cultures of Sporosarcina ureae and one culture of Bacillus pasteurii was determined using the methods of Marmur and Doty (1962), Frédéricq et al. (1961), and paper chromatography. The GC content in DNA of Sporosarcina ureae ranges from 39.3 to 44%. Bacillus pasteurii contained 40.4% GC in DNA. Our results support the opinion that Sporosarcina ureae is related both to non-sporeforming flagellated cocci of the genus Planococcus and to bacilli, particularly to Bacillus pasteurii.     

Deoxyribonucleic acid base composition of pediococci and aerococci

Summary The guanine+cytosine content (GC) of DNAs of 9 strains of pediococci and 6 strains of aerococci was determined using different physicochemical methods. It was found that the GC content of DNA of the pediococci ranged from 37.8 to 41.2%, while that of the aerococci varied from 42.0 to 43.2%. The results obtained show that genetically related species are involved whose mutual position in the system is determined by only slight differences in the phenotype.     

Deoxyribonucleic acid base composition of some micrococci and sarcinae

The strains designated in this paper asMicrococcus lysodeikticus, M. sodonensis, M. flavus, Sarcina flava, S. pelagia, S. variabilis, S. marginata, S. subflava, S. citrea, S. lutea andStaphylococcus afermentans have similar DNA base compositions. The mole % GC (guanine plus cytosine) contents in DNA of these strains ranged from 71.8 to 73.3 as calculated from the denaturation temperature (Tm). They may be, therefore, closely related. However, at variance with Kocur and Martinec (1962) they do not seem to be identical withMicrococcus luteus (Schroeter 1872) Cohn 1872, because the neotype culture of the latter species has a different content of guanine and cytosine in its DNA (GC=66.3%). Sarcina aurantiaca, Micrococcus dentrificans andM. luteus have a similar DNA base composition. However, they are not identical as they differ from each other in several physiological characters. In the strains designated asStaphylococcus roseus andSarcina erythromyxa the content of GC varies within the range 72–72.8%. These species do not differ from each other physiologically. They form a pink pigment, reduce nitrates, do not hydrolyze casein and gelatin, and do not produce urease. They seem, therefore, to be identical, which confirms the conclusion of Kocur and Martinec (1962) who designated them asMicrococcus roseus Flügge 1886. Micrococcus conglomeratus differs significantly in DNA base composition from almost all strains of the groupM. lysodeikticus—Staphylococcus afermentans, also fromMicrococcus luteus, M. roseus andM. denitrificans. It differs fromSarcina aurantiaca only physiologically.     

Morphology,nutrition and physiology of Sphaerotilus discophorus

Summary By means of hay infusion-Fe(OH)₃–MnCO₃ enrichment cultures, 11 pure strains of the filamentous, sheathed bacterium, Sphaerotilus discophorus were isolated from streams, rivers and lakes. The morphology of the colonies, filaments and cells are shown in a series of photographs. The strains grew well in dilute organic media but not in many of the common bacteriological media. All strains required thiamin and biotin for growth. Glucose, mannitol, salicin, raffinose, glycerol and other compounds were suitable energy sources and peptone and casein hydrolysate were satisfactory nitrogen sources for growth. The temperature range for growth was 5–35°C and the pH range 6.0–8.6.The sudanophilic granules of S. discophorus are composed of poly--hydroxybutyric acid which may be as much as 40% of the dry weight of the cells. Growth with iron and manganese salts results in extensive deposition of oxides on these metals on the filaments. Chemical analyses of 60 hr cultures showed that the iron content of the filaments ranged from 4.25–7.10% and manganese from 1.12–1.43%, calculated on a dry weight basis. Resting cell suspensions oxidized a variety of sugars, sugar alcohols, amino acids and other compounds and concomitantly assimilated about 90% of these substrates. The properties of S. discophorus are compared with those of S. natans.Based in part on a thesis presented by the senior author in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Washington State University, 1963.     

Deoxyribonucleic acid base composition and genome size of Prochloron

The DNA base composition of the photosynthetic prokaryote Prochloron was determined (on samples collected from the natural environment) to be 40.8 mol% GC. The sharp differential melting curve indicated the absence of significant quantities of contaminating DNA from other organisms. The genome size, estimated from the renaturation kinetics of thermally denatured DNA, was 3.59×10⁹ daltons mol. wt, similar to that of many other prokaryotes. The fact that Prochloron has not yet been cultured in the laboratory cannot, therefore, be attributed to a reduced genetic information content.     

Deoxyribonucleic acid base composition and taxonomy of violet-pigmented cocci

The content of guanine and cytosine in DNA of the violet-pigmented micrococci designated asStaphylococcus flavocyaneus andMicrococcus flavocyaneus varies within the range of 70.8 – 72.0%. These species have similar deoxyribonucleic acid base compositions and do not differ physiologically and morphologically: they both produce yellow and violet pigments, hydrolyse gelatin and casein, reduce nitrates and do not form lipase. Therefore we consider them in accordance with Kocur and Martinec (1962, 1963) identical. They do not, however, seem to be identical withMicrococcus luteus (Schroeter, 1872) Cohn 1872 because the content of guanine and cytosine in DNA of the neotype culture of this species was found to be 66.3%.Micrococcus luteus differs from the violet pigmented micrococci also physiologically. It does not produce violet pigment, does not hydrolyse gelatin and casein and does not produce urease. For the violet pigmented strainMicrococcus cyaneus the use of the original designation is recommended:Micrococcus cyaneus (Schroeter) Cohn 1872, as it differs from the other violet cocci not only physiologically — it does not produce yellow pigment, oxidises mannitol, dulcitol and sorbitol, produces lipase and does not hydrolyse casein — but also in its DNA base composition.     

Magnesium uptake by Sphaerotilus natans

Aim of the present paper is to give a contribution for a better understanding of the mechanism of magnesium accumulation by cells of Sphaerotilus natans. The results presented in this paper seem to confirm the non strictly biological nature of the phenomenon. An inhibiting effect of ethanol on the uptake is also evidenced and a hypothesis for the inhibition mechanism, implying the simultaneous occurrence of both physical and biological phenomena, is presented. In the presence of ethanol a film around the cell membrane is likely to be produced, partially preventing the adhesion of magnesium ions on the wall; subsequently, ethanol would be transformed into acetic acid and magnesium removed from the cell wall as a salt. All the efforts to improve the process yields and the resistance of the microorganism to ethanol, through specific adaptions, have not given the expected results.     

Role of iron deposition in Sphaerotilus discophorus.

Various physiological aspects of the process of iron deposition in Sphaerotilus discophorus were examined to elucidate its role. The values of iron/protein ratios suggested that a direct relationship existed between the iron concentration of the media and the magnitude of final iron deposition. Saturation of the organism's iron deposition system occurred at a 2.0 mM iron concentration, at a value of 0.6 mg of ferric ion per mg of cell protein. Laboratory data indicated that the strain's very low capacity for iron deposition observed at low external iron concentrations makes it unlikely that it is significant in limiting iron in the natural milieu. Under optimal iron concentrations, however, strain SS1 caused precipitation of iron (adsorbed to cellular material) in broth cultures, which was 10 to 100 times that mediated by some "non-iron" microorganisms. The strain's iron requirement, which was found to be between 0.003 and 0.02 mM, is commensurate with that of other microbes. One hundred micrograms of Mn(II) per ml and possibly 10 mug of either Co(II) or Ni(II) per ml could inhibit iron uptake in the deposition system. Sphaerotilus, when tested for its ability to withstand toxic concentrations of certain trace elements (Co, Cu, Mn, Ni, and Cd), demonstrated no exceptional resistance with respect to several other common microorganisms. Final cell yields were not affected by a varying iron concentration for Sphaerotilus growing under conditions of limiting carbon and nitrogen.