Polar lipids of non-alkaliphilic Halococci.

Until recently, only one species of Halococcus has been recognized, namely, H. morrhuae, but a large number of extremely halophilic non-alkaliphilic cocci have now been isolated from hypersaline habitats in Spain and classified into four phenons (A-D); one of the phenon D strains has been classified as a new species, Halococcus saccharolyticus. Examination of the lipids of H. saccharolyticus and four strains of phenons A-C showed the presence in all of them of C20-C20 and C20-C25 diether molecular species of phosphatidylglycerophosphate (PGP), phosphatidylglycerol (PG) and phosphatidic acid (PA); a monounsaturated isoprenoid C20-C20 (phytanyl-phytenyl) species of PGP; a sulfated diglycosyl diphytanylglycerol (S-DGD) with structure 2,3-diphytanyl-1-(6-HSO3-mannosyl-1-2-glucosyl)-glycerol, which is identical to the S-DGD-1 in Haloferax mediterranei; a phosphoglycolipid (P-TGD) tentatively identified as a phytanyl-phytenyl-(H2PO3-galactosyl-mannosyl-glycosyl)-glyce rol, and two unidentified glycolipids present only in traces. No phosphatidylglycerosulfate (PGS) was detected in any of the strains examined. This pattern of lipids appears to be characteristic of the strains of Halococcus from salterns in Spain, but studies of a larger number and variety of Haloccus are necessary to establish this conclusion with certainty.

The effect of temperature on the growth and lipid composition of the extremely halophilic coccus, Sarcina marina.

Sarcina marina (NCMB 778) grew over the temperature range 20-45 degrees C but no growth was recorded at 15 degrees C or 50 degrees C. At the optimum growth temperature of 34 degrees C the doubling time was 14.5 h. The major polar lipid components, tentatively identified as the diether analogues of phosphatidyl glycerophosphate (PGP), phosphatidyl glycerol (PG), diglycosyl diglyceride (DGD) and triglycosyl diglyceride (TGD), and the major neutral lipid components, tentatively identified as squalene, dihydrosqualene, tetrahydrosqualene, vitamin MK8, geranyl geraniol and di-O-phytanyl glycerol, are identical to those found in other extremely halophilic rods and cocci. The total lipid content varied with growth conditions from 0.6-3.2% of the dry cell weight, polar lipids accounted for between 94.3 and 83.6% of the total lipid, the remainder being neutral lipid. In response to both the transition from exponential to stationary phase and a reduction of 14 degrees C in growth temperature, batch cultures showed: (i) an increase in total lipid content; (ii) a decrease in PG and (iii) an increase in PGP. Specific responses to the temperature decrease were (i) increased total lipid content; (ii) no decrease in neutral lipids in stationary phase; (iii) marked reduction in PG and (iv) raised DGD. (i) and (ii) could be mechanisms for increasing membrane fluidity. In common with all other extreme halophiles investigated the alkyl side chains of S. marina polar lipids were identified as the phytanyl (3R, 7R, 11R, 15-tetramethylhexadecyl) group. Its structure did not appear to vary with temperature so that the normal mechanisms for modifying the structure of lipid alkyl side chains to modulate membrane fluidity in response to temperature changes probably does not occur in this group of microorganisms.

A simple method for the determination of DNA molecular weight distribution.

A method is described for the molecular weight distribution of DNA which is determined from sedimentation-velocity analysis. Knowing the distribution of sedimentation coefficients for a single DNA concentration it is possible to extrapolate such a distribution to infinite dilution of the solute in a simple way. Two versions (using two or three terms of a series) of extrapolating equations are considered and discussed in detail. The sedimentation coefficients distribution calculated from these equations differs only insignificantly with that obtained in a conventional way.

Occurrence of indole in cells of extremely halophilic bacteria.

The neutral lipids of several halophilic bacteria contain a non-isoprenoid compound which was identified by its chromatographic and spectroscopic properties as indole.

[Optimal conditions for determing ATP of microbial origin]. / Optimal'nye usloviia opredeleniia ATF mikrobnogo proiskhozhdeniia.

Endogenous luminescence of the luciferin-luciferase extract from firely tails was studied in determing low concentrations of ATP. The optimum concentration of the the extract, corresponding to the minumum effect of endogenous luminescence, was found in the reaction medium. The solution of luciferin-luciferase was unstable at room temperature and upon dilution. The activity of luciferin-luciferse solutions did not change after freezing in liquid nitrogen with following thawing. The content of ATP was assayed in the cells of Sarcina flava disintegrated with ultrasound.

Classification of micrococci on the basis of deoxyribonucleic acid homology.

The DNA homology relationships of 25 micrococci (15 strains of Micrococcus, eight strains of Sarcina and two strains of Staphylococcus) were studied by the deoxyribonucleic acid hybridization method using nuclease S1, an endonuclease specific for single-stranded DNA molecules. Nineteen of the strains were classified into three groups. Group I contained Micrococcus lysodeikticus IAMI056, M. luteus IAMI1010, M. flavus IAMI2005 and IAMI2006, Sarcina flava IAMI2007 and IAMI1006. S. subflava IAMI2009, S. lutea ATCC381, and ATCC382, and M. luteus IAMI1006. Group II contained M. roseus IAMI315, ATCC412, ATCC185 and IAMI295. Group III contained S. lutea IAMI099, IFO3232 and ATCC383, M. varians ATCC399 and Staphylococcus lactis ATCC15306. Micrococcus luteus IAMI097, M. varians ATCC19099 and ATCC19100, M. conglomeratus IAMI459 and IAMI470, and St. aureus IAMI011 could not be assigned to any of the three groups. The grouping corresponds to that derived from the results of differential lysis by lysozyme, 'lytic enzyme 2' from Cytophaga sp., or Streptomyces albus G enzyme; and to types of peptidoglycan in the cell walls and genetic transformation. The usefulness of classification based on sensitivity to various lytic enzymes was demonstrated. Group I probably coincides with M. luteus of Bergey's Manual of Determinative Bacteriology (1974), and groups II and III with M. roseus and M. varians respectively.

New isoprenologs of vitamin K2 series in Sarcina lutea.

Four new menaquinone homologs have been isolated and characterized from Sarcina lutea. The use of purified silica gel G in the isolation of pure menquinones from bacterial nonpolar lipids has been developed. During this procedure, fractionation of any naturally occuring menaquinones with sidechain variation takes place. The structures of the isolated menaquinones have been elucidated by UV-, and mass spectrometry, and by their corresponding hydroquinones and layer chromatography properties. Thus, Sarcina lutea has been shown to produce four homologs of dihydromenaquinones, i.e., dihydromenaquinone-6,-7,-8, and -9.

Amino sugar and amino acid constituents of the cell walls of the extremely halophilic cocci.

Cell wall hydrolysates of nine strains of extremely halophilic cocci all contained gylcine, glucosamine, galactosamine, and gulosaminuronic acid. Muramic acid was not present in any of the strains.

Variation of type-B DNA x-ray fiber diagrams with base composition.

Eight natural DNAs of widely differing base composition have been studied by x-ray diffraction in fibers at high relative humidity. The resulting type B diffraction diagrams showed that all of the DNAs had a 34-A pitch and 3.4-A interbase pair separation. However, the intensity distribution on the inner three layer lines was a strong function of the base content. In diffraction diagrams of very AT-rich DNA, the intensity of the first and third layer line was 2- or 3-times stronger than in the patterns of GC-rich DNA. These high humidity diffraction patterns agree with x-ray scattering from solutions of DNA. The results are interpreted to imply that each AT base pair may have a different cross section than a GC pair. If this is so, it would appreciably alter the currently held ideas concerning DNA recognition.