Eukaryotic organisms have been shown to have multiple forms of hsp7O-da stress-related proteins, but only a sngle family member, DnaK, has been found in prokaryotes. We report here the Identification of a heat shock cognate gene, hsc, in Escherichia cofi. The amino acid sequence deduced from hsc predicts a 65,647-Da polypeptide having 41% sequence identity with DnaK fromE. coil, and overexpression produces a protein (Hsc66) with properties smilar to DnaK. In contrast to dnaK, however, the hsc gene lacks a consensus heat shock promoter sequence, and expression is not induced by elevated temperature. The hsc gene is located near 54 min on the physical map, immiaely upstream of the fdx gene, which encodes a [2Fe-2S] ferredoxin; evidence is presented that the hsc and fdx genes make up a blcistronic operon in which expression of the ferredoxin is coupled to that of Hsc66. The function of Hsc66 is not known, but the coregulatio of its expression with that of ferredoxin suggests the possibility of a specific role in association with the ferredoxin protein.The 70-kDa heat shock proteins (hsp70) and their cognates (hsc70) make up a ubiquitous, multigene family of highly conserved proteins, which are involved in diverse proteinprotein interactions (reviewed in ref.
Clinical specimens from 9 states during 2008-2010 were tested by PCR for Bordetella pertussis and Bordetella parapertussis. Of the positive samples, 13.99% were identified as B. parapertussis. It was concluded that B. parapertussis infections are more common than previously realized and contribute to cases thought to be vaccine failures.
We have cloned the radl gene of Schizosaccharomyces pombe by complementation of the radl-l mutant, which is deficient in DNA repair and recombination. The coding region of the gene is 582 base pairs long and contains no introns. The predicted product is a strongly acidic, 22-kilodalton protein containing 194 amino acid residues. This gene does not exhibit significant homology to any other known repair gene. The major transcription start site is at 27 base pairs upstream of the putative start codon. Insertion mutagenesis revealed that besides the coding region, at least 151 base pairs of 5'-flanking sequence are required for full complementing activity. A strain carrying a null allele of radi was constructed and found to have a phenotype closely similar to that of the radl-I mutant. Expression in Escherichia coli of the coding region yielded a protein product of a size close to that predicted from the DNA sequence. This product reacted with antibodies raised against a synthetic peptide with a sequence from that predicted for the protein product. We have localized the radi gene to NotI fragment E of the S. pombe genome.Schizosaccharomyces pombe is a comparatively radioresistant organism. It is roughly the same cell size and genome complexity as Saccharomyces cerevisiae, yet it will tolerate an order-of-magnitude-higher dose of UV or ionizing radiation (34, 47). Thus, S. pombe likely has efficient DNA repair systems. It is held that recombinational pathways play a major role in eliminating DNA damage in S. pombe (11,13,29,34). Although the predominant life phase in this organism is haploid, S. pombe, like mammalian cells but unlike Saccharomyces cerevisiae, spends a major part of the cell cycle in G2, where a sister chromatid is present to provide an intact DNA copy for recombinational repair (34).Three pathways for repair of radiation-induced DNA damage have been preliminarily identified in S. pombe (11,12,31,34). The first, acting both on UV-and gamma radiation-induced damage, requires postirradiation protein synthesis for full efficiency (12). The second, acting on gamma radiation-induced damage only, and the third, acting on UV damage only, require no postdamage protein synthesis (11,12).Evidence for the involvement of individual genes in these pathways comes from the collection of radiation-sensitive (rad) S. pombe mutants, representing 23 distinct loci (23,31,41). None of the genes defined by these mutants have been cloned previously. radl mutants are sensitive to both UV and gamma radiation (31) and are not further sensitized by inhibition of protein synthesis (12); hence, radl has tentatively been assigned to the first pathway. Some rad mutants, including rad5 and radl3, display an enhanced degree of UV-induced mutability. However, radl cells along with mutants in other loci thought to belong to the same repair pathway have decreased rates of UV-induced mutation (15,29 Caffeine inhibits intergenic recombination in S. pombe (24) and also decreases survival after treatment with chemical mutagens or with UV or...
Clinical, epidemiological, and laboratory diagnostic issues of human monocytotropic ehrlichiosis (HME) were investigated in a retrospective case study conducted at a national reference laboratory (Focus Technologies, formerly MRL Reference Laboratory), and at the University of Texas Medical Branch at Galveston, Texas, during 1997 and 1998. Standard questionnaires were sent to physicians for each laboratory-diagnosed patient 2 days to 2 weeks after immunofluorescent antibody assay results were available. Among the 41 cases for which data were obtained, 32 (78%) were definite cases of HME, and 9 (22%) were probable cases of HME. Tick bite or exposure to ticks was recorded in more than 97% of cases. The most prominent clinical findings were fever, abdominal tenderness, and regional lymphadenopathy. There was an association between age and severity of illness. The main laboratory findings included leukopenia, thrombocytopenia, and elevated aspartate aminotransferase and alanine aminotransferase. Clinical and laboratory findings were nonspecific and were not good predictors of the severity of illness. The 90% of patients who received doxycycline treatment underwent rapid clinical improvement with a favorable outcome. The usual duration of effective treatment with doxycycline was 7 to 10 days. This retrospective study is unique because it was based in a commercial reference laboratory setting that receives specimens from different geographic locations. The clinical and laboratory information from 41 patients provides insight into the epidemiological, clinical, and laboratory characteristics of HME.
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