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1.
In order to study the occurrence of mycoplasmas among Norwegian sheep, lungs from a great number of different herds were collected at 3 abattoirs in Southern Norway. The presence of fermenting mycoplasmas and bacteria was examined in both normal and pneumonic lungs to determine whether recovery of these agents could be related to pneumonic changes. Pneumonic lungs demonstrated lesions typical of the condition described as subacute or chronic pneumonia. Mycoplasma ovipneumoniae was found in 87 % of the 126 pneumonic lungs and in 6 % of the 83 normal lungs. Bacteria, mostly Pasteurella haemolytica, were less frequently encountered in the pneumonic lungs, and usually in combination with M. ovipneumoniae. It is concluded that M. ovipneumoniae is widespread among sheep in Southern Norway and can be considered to have etiological significance in subacute or chronic pneumonia, whereas bacteria probably occur mainly as secondary invaders. Changes resulting from moderate invasion by lungworm were found in about half of the lungs, but just as frequently in normal as in pneumonic lungs, and accordingly did not appear to contribute to the pneumonia investigated. 相似文献
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Javier Pe?a-Diaz Siv A. Hegre Endre Anderssen Per A. Aas Robin Mjelle Gregor D. Gilfillan Robert Lyle Finn Drabl?s Hans E. Krokan P?l S?trom 《Nucleic acids research》2013,41(5):2846-2856
Genome-wide gene expression analyses of the human somatic cell cycle have indicated that the set of cycling genes differ between primary and cancer cells. By identifying genes that have cell cycle dependent expression in HaCaT human keratinocytes and comparing these with previously identified cell cycle genes, we have identified three distinct groups of cell cycle genes. First, housekeeping genes enriched for known cell cycle functions; second, cell type-specific genes enriched for HaCaT-specific functions; and third, Polycomb-regulated genes. These Polycomb-regulated genes are specifically upregulated during DNA replication, and consistent with being epigenetically silenced in other cell cycle phases, these genes have lower expression than other cell cycle genes. We also find similar patterns in foreskin fibroblasts, indicating that replication-dependent expression of Polycomb-silenced genes is a prevalent but unrecognized regulatory mechanism. 相似文献
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Fifty-three beta-lactamase-producing strains of oral bacteria isolated from patients with refractory periodontitis in Norway and USA were screened for the presence of the bla(TEM), bla(SHV), bla(OXA), bla(ampC), bla(cfxA), and bla(cepA/cblA) genes by the polymerase chain reaction (PCR). The PCR products were characterized by direct sequencing of the amplified DNA. Thirty-four of the 53 enzyme-producing strains (64%) were positive in one of the PCR assays. All beta-lactamase-producing Prevotella and Capnocytophaga spp. were CfxA positive. TEM-type beta-lactamases were identified in one strain each of Escherichia coli and Neisseria sp., and one strain of Citrobacter freundii possessed an AmpC-type beta-lactamase. Screening for gene cassettes and genes known to be associated with integrons did not reveal the presence of integrons in these oral bacteria. Sequence analyses showed that most CfxA positive Prevotella and Capnocytophaga isolates from patients with refractory periodontitis harboured variants of the CfxA2 and CfxA3 enzyme. The present study also showed that many different genetic determinants of beta-lactamase production are found in bacteria isolated from refractory periodontitis, many of which remain to be characterized. 相似文献
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The physical distribution of ten simple-sequence repeated DNA motifs (SSRs) was studied on chromosomes of bread wheat, rye
and hexaploid triticale. Oligomers with repeated di-, tri- or tetra-nucleotide motifs were used as probes for fluorescence
in situ hybridization to root-tip metaphase and anther pachytene chromosomes. All motifs showed dispersed hybridization signals
of varying strengths on all chromosomes. In addition, the motifs (AG)12, (CAT)5, (AAG)5, (GCC)5 and, in particular, (GACA)4 hybridized strongly to pericentromeric and multiple intercalary sites on the B genome chromosomes and on chromosome 4A of
wheat, giving diagnostic patterns that resembled N-banding. In rye, all chromosomes showed strong hybridization of (GACA)4 at many intercalary sites that did not correspond to any other known banding pattern, but allowed identification of all R
genome chromosome arms. Overall, SSR hybridization signals were found in related chromosome positions independently of the
motif used and showed remarkably similar distribution patterns in wheat and rye, indicating the special role of SSRs in chromosome
organization as a possible ancient genomic component of the tribe Triticeae (Gramineae).
Received: 13 February 1998; in revised form: 18 August 1998 / Accepted: 18 August 1998 相似文献
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An amphipathic cyclic tetrapeptide scaffold containing halogenated β2,2‐amino acids with activity against multiresistant bacteria 下载免费PDF全文
Marianne H. Paulsen Eskil André Karlsen Dominik Ausbacher Trude Anderssen Annette Bayer Philipp Ochtrop Christian Hedberg Tor Haug Johanna U. Ericson Sollid Morten B. Strøm 《Journal of peptide science》2018,24(10)
The present study describes the synthesis and biological studies of a small series of head‐to‐tail cyclic tetrapeptides of the general structure c(Lys‐β2,2‐Xaa‐Lys) containing one lipophilic β2,2‐amino acid and Lys, Gly, Ala, or Phe as the Xaa residue in the sequence. The peptides were investigated for antimicrobial activity against gram‐positive and gram‐negative reference strains and 30 multiresistant clinical isolates including strains with extended spectrum β‐lactamase—carbapenemase (ESBL‐CARBA) production. Toxicity was determined against human red blood cells. The most potent peptides showed high activity against the gram‐positive clinical isolates with minimum inhibitory concentrations of 4–8 μg/mL and low haemolytic activity. The combination of high antimicrobial activity and low toxicity shows that these cyclic tetrapeptides containing lipophilic β2,2‐amino acids form a valuable scaffold for designing novel antimicrobial agents. 相似文献
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