DNA BASE COMPOSITION OF SOME FREE-LIVING NEMATODE SPECIES

1969 ◽  
Vol 11 (4) ◽  
pp. 993-1000 ◽  
Author(s):  
R. Behme ◽  
J. Pasternak
Keyword(s):  
Refractive Index ◽  
Base Composition ◽  
Buoyant Density ◽  
Gc Content ◽  
Nematode Species ◽  
Refractive Index Gradient ◽  
Free Living ◽  
Dna Base Composition ◽  
Dna Base ◽  
Dnase Treatment

The mean base compositions (% GC) of DNA samples from five free-living nematodes were determined by CsCl equilibrium buoyant-density centrifugation and thermal denaturation studies. Both methods gave similar results indicating that there is no extensive replacement of the usual bases in nematode DNA. From the ultracentrifugation studies the % GC content of the DNA of Caenorhabditis briggsae (Dougherty and Nigon, 1949) Dougherty, 1953, Turbatrix aceti (Müller, 1783) Peters, 1927, Rhabditis (Rhabditis) anomala Hertwig, 1922 (Dougherty 1955), Panagrellus redivivus (Linn, 1767) T. Goodey, 1945, and Panagrellus silusiae (de Man, 1913) T. Goodey, 1945 was 36, 40, 42, 44 and 44, respectively.The sample of DNA from T. aceti showed two distinct ultraviolet absorbing bands in a CsCl gradient. The band at 1.688 g/cm3 proved to be a polysaccharide. It gave a distinctive refractive index pattern when viewed with the schlieren optical system, was insensitive to DNase treatment and was removed by a-amylase treatment. On the other hand, the material banding at 1.699 g/cm3 was shown to be DNA. This band produced no disturbance in the refractive index gradient. It was not altered by a-amylase treatment, but it was DNase sensitive.Since P. redivivus and P. silusiae were found to have the same DNA base composition their ability to interbreed was examined. These two forms were cross-fertile and the offspring were fully fertile.

DNA base composition of filarial nematodes

Parasitology ◽  
1988 ◽  
Vol 97 (1) ◽  
pp. 75-79 ◽  
Author(s):  
N. Rothstein ◽  
T. J. Stoller ◽  
T. V. Rajan
Keyword(s):  
Base Composition ◽  
Thermal Denaturation ◽  
Gc Content ◽  
Direct Analysis ◽  
Molar Content ◽  
Free Living ◽  
Dna Base Composition ◽  
Base Content ◽  
Dna Base ◽  
Filarial Nematodes

SUMMARYWe have determined the molar content of guanine + cytosine (GC content) of DNA of the filarial nematode (Brugia malayi, Brugia pahangi and Dirofilaria imitis) and of the free-living soil nematodes Caenorhabditis elegans and have analysed the DNA for the presence of methylcytosine. Two independent methods, thermal denaturation and direct analysis of base content by HPLC following enzymatic hydrolysis, reveal that the GC content of filarial nematodes is 26–28%. We have been unable to find methylcytosine in the DNA of B. malayi.

DNA base composition, nature of intracellular DNA, morphology, and classification of bacteriophages infecting Micrococcus luteus

1979 ◽  
Vol 25 (9) ◽  
pp. 1027-1035 ◽  
Author(s):  
Scott W. Compton ◽  
John A. Mayo ◽  
Melanie Ehrlich ◽  
H. W. Ackermann ◽  
Lise Tremblay ◽  
...  
Keyword(s):  
Host Range ◽  
Base Composition ◽  
Micrococcus Luteus ◽  
Gc Content ◽  
Dna Base Composition ◽  
Bacterial Virus ◽  
Double Stranded Dna ◽  
Dna Base

Ten bacteriophages infecting Micrococcus luteus have been characterized. All phages contain double-stranded DNA, of 64.3–73.5 mol% guanine plus cytosine (GC). The DNA of phage N7 has the highest GC content reported for any bacterial virus. No unusual bases have been found. The intracellular replicating DNAs of six phages are covalently closed circular molecules. All 10 phages have isometric, probably icosahedral, heads and long, flexible, noncontractile tails and can be sorted into two morphological groups based on size and presence or absence of a collar. Host-range studies indicate six host-range groups.

scholarly journals Lifestyle and DNA base composition in polychaetes

2016 ◽  
Vol 48 (12) ◽  
pp. 883-888
Author(s):  
Andrea Tarallo ◽  
Maria Cristina Gambi ◽  
Giuseppe D'Onofrio
Keyword(s):  
Metabolic Rate ◽  
Base Composition ◽  
Gc Content ◽  
Active Lifestyle ◽  
Dna Base Composition ◽  
Polychaete Species ◽  
Dna Base ◽  
Biased Gene Conversion ◽  
Relationship Of ◽  
Genomic Gc Content

A comparative analysis of polychaete species, classified as motile and low-motile forms, highlighted that the former were characterized not only by a higher metabolic rate (MR), but also by a higher genomic GC content. The fluctuation of both variables was not affected by the phylogenetic relationship of the species. Thus, present results further support that a very active lifestyle affects MR and GC at the same time, showing an unexpected similarity between invertebrates and vertebrates. In teleosts, indeed, a similar pattern has been also observed in comparisons of migratory and nonmigratory species. A cause-effect link between MR and GC has not yet been proved, but the fact that the two variables are significantly linked in all the organisms so far analyzed is, most probably, of relevant biological and evolutionary meaning. The present results fit very well within the frame of the metabolic rate hypothesis proposed to explain the DNA base composition variability among organisms. On the contrary, the thermostability hypothesis was not supported. At present, no data about the recombination rate in polychaetes were available to test the biased gene conversion (BGC hypothesis).

scholarly journals II. Charakterisierung der schnellmarkierten RNS

1968 ◽  
Vol 23 (9) ◽  
pp. 1198-1208 ◽  
Author(s):  
R. Wollgiehn ◽  
M. Ruess
Keyword(s):  
Base Composition ◽  
Actinomycin D ◽  
Gc Content ◽  
The Other ◽  
Nucleic Acid Metabolism ◽  
Dna Base Composition ◽  
Dna Base ◽  
Molecular Fraction ◽  
Young Leaves ◽  
Short Time

The nucleic acid metabolism of young leaves (Nicotiana rustica, Pisum sativum) was investigated by 32P-labelling in short-time experiments. The nucleic acids were extracted quantitatively with buffer, containing SDS, and fractionated on the MAK column. Several rapidly labelled RNA fractions were found in the region of sRNS, DNA and rRNA. We have characterized two rapidly labelled fractions more detailed. The first one is a high molecular AU-RNA, which is eluted from the MAK column after the rRNA. The second one is a low molecular fraction in the region of the sRNA.The AU-RNA has the following properties: 1) It is rapidly labelled in pulse experiments. 2) the halfe-life of the AU-RNA in chase experiments is 4 hours at its maximum, showing faster degradation compared to the other fractions. 3) The 32P-incorporation is quantitatively inhibited by actinomycin D. 4) The base composition resembles DNA base composition (high AU and low GC content) . 5) AU-RNS appears as a heterogeneous fraction in the sucrose gradient, and sediments similar to rRNA. 6) AU-RNA occurs in all particle fractions of the homogenates.The low molecular, rapidly labelled RNA shows the following properties: 1) The radioactive peak does not correspond with 4 S or 5 S RNA peaks. 2) This RNA is metabolically stable, the radioactivity decreases very slowly in chase-experiments. 3) The 32P-incorporation is less inhibited by actinomycin D than the other RNA fractions. 4) The base composition is not similar to DNA base composition. A high content of labelled CTP in this RNA fraction may indicate the rapid 32P-incorporation by exchange of the terminal CpCpA group of tRNA.The possible messenger function of the AU-RNA is discussed.

DNA BASE COMPOSITION OF CYTOPHAGA MARINOFLAVA N. SP. DETERMINED BY BUOYANT DENSITY MEASUREMENTS IN CESIUM CHLORIDE

1966 ◽  
Vol 12 (6) ◽  
pp. 1099-1103 ◽  
Author(s):  
R. R. Colwell ◽  
R. V. Citarella ◽  
P. K. Chen
Keyword(s):  
Nucleic Acid ◽  
Base Composition ◽  
Marine Bacterium ◽  
Deoxyribonucleic Acid ◽  
Buoyant Density ◽  
Cesium Chloride ◽  
Dna Base Composition ◽  
Density Measurements ◽  
Dna Base ◽  
Relationship Of

A marine bacterium, NCMB 397, host strain for bacteriophages NCMB 384 and 385, has been subjected to taxonoinic analysis. Overall base composition of the highly purified deoxyribonucleic acid was determined and found to be 37 moles % guanine + cytosine. The phenetic and nucleic acid data suggest significant relationship of this strain and members of the genus Cytophaga. A description of Cytophaga marinoflava n. sp. is presented.

Mutants with altered DNA base composition inBacterium paracoli — the evidence from a marker

1971 ◽  
Vol 11 (2) ◽  
pp. 91-95 ◽  
Author(s):  
G. F. Gause ◽  
A. V. Laiko ◽  
M. V. Bibikova ◽  
L. I. Kusovkova ◽  
T. I. Selesneva ◽  
...  
Keyword(s):  
Base Composition ◽  
Dna Base Composition ◽  
Dna Base
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