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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 3-kb fragment of Haemophilus haemolyticus DNA which carries the HhaII restriction (r) and modification (m) genes has been cloned into the PstI site of pBR322 (Mann et al., 1978). When propagated in Escherichia coli, it was observed that spontaneous insertions of IS5 inactivated the restriction gene, producing r- mutants at a frequency of 10(-6). Electron microscopy, restriction-site mapping and sequence analysis of two r- plasmids have demonstrated the presence of IS5 at a single target site in both possible orientations. The complete nucleotide sequence of IS5 has been determined. It is 1195 bp long and has inverted terminal repeats of 16 bp. The target site for IS5 in this plasmid is 5'-CTAG. Approx. ten copies of IS5 were found to be present at about the same locations on the E. coli chromosome in various K-12 strains, using Southern hybridization analysis.
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PMID:The nucleotide sequence of IS5 from Escherichia coli. 626 59

We compare and contrast genome-wide compositional biases and distributions of short oligonucleotides across 15 diverse prokaryotes that have substantial genomic sequence collections. These include seven complete genomes (Escherichia coli, Haemophilus influenzae, Mycoplasma genitalium, Mycoplasma pneumoniae, Synechocystis sp. strain PCC6803, Methanococcus jannaschii, and Pyrobaculum aerophilum). A key observation concerns the constancy of the dinucleotide relative abundance profiles over multiple 50-kb disjoint contigs within the same genome. (The profile is rhoXY* = fXY*/fX*fY* for all XY, where fX* denotes the frequency of the nucleotide X and fY* denotes the frequency of the dinucleotide XY, both computed from the sequence concatenated with its inverted complementary sequence.) On the basis of this constancy, we refer to the collection [rhoXY*] as the genome signature. We establish that the differences between [rhoXY*] vectors of 50-kb sample contigs of different genomes virtually always exceed the differences between those of the same genomes. Various di- and tetranucleotide biases are identified. In particular, we find that the dinucleotide CpG=CG is underrepresented in many thermophiles (e.g., M. jannaschii, Sulfolobus sp., and M. thermoautotrophicum) but overrepresented in halobacteria. TA is broadly underrepresented in prokaryotes and eukaryotes, but normal counts appear in Sulfolobus and P. aerophilum sequences. More than for any other bacterial genome, palindromic tetranucleotides are underrepresented in H. influenzae. The M. jannaschii sequence is unprecedented in its extreme underrepresentation of CTAG tetranucleotides and in the anomalous distribution of CTAG sites around the genome. Comparative analysis of numbers of long tetranucleotide microsatellites distinguishes H. influenzae. Dinucleotide relative abundance differences between bacterial sequences are compared. For example, in these assessments of differences, the cyanobacteria Synechocystis, Synechococcus, and Anabaena do not form a coherent group and are as far from each other as general gram-negative sequences are from general gram-positive sequences. The difference of M. jannaschii from low-G+C gram-positive proteobacteria is one-half of the difference from gram-negative proteobacteria. Interpretations and hypotheses center on the role of the genome signature in highlighting similarities and dissimilarities across different classes of prokaryotic species, possible mechanisms underlying the genome signature, the form and level of genome compositional flux, the use of the genome signature as a chronometer of molecular phylogeny, and implications with respect to the three putative eubacterial, archaeal, and eukaryote domains of life and to the origin and early evolution of eukaryotes.
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PMID:Compositional biases of bacterial genomes and evolutionary implications. 919 Aug 5