Region II of the <i>Haemophilus influenzae</i> Type b capsulation locus as involved in serotype‐specific polysaccharide synthesis

Eldere, Johan Van; Brophy, L. N.; Loynds, B M; Celts, Patrick; Hancock, I.C.; Carman, Stephen; Kroll, J. Simon; Moxon, E. Richard

doi:10.1111/j.1365-2958.1995.tb02225.x

Cited by 55 publications

(55 citation statements)

References 41 publications

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“…Five Hib LAMP primers were designed based on published sequences of the Hib capsulation locus region II (GenBank accession no. X78559) using the LAMP primer support software program (Net Laboratory, Kanagawa, Japan) (22). The Hib LAMP primers included two outer primers (F3 Analysis of Hib LAMP products.…”

Section: Bacterialmentioning

confidence: 99%

Loop-Mediated Isothermal Amplification Assay for Detection of Haemophilus influenzae Type b in Cerebrospinal Fluid

et al. 2011

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Haemophilus influenzae type b (Hib) is one of the leading causes of meningitis in developing countries. To establish and evaluate a novel loop-mediated isothermal amplification (LAMP) assay for Hib, we designed a LAMP primer set targeting the Hib-specific capsulation locus. LAMP detected 10 copies of purified DNA in a 60-min reaction. This indicated that the detection limit of LAMP was >100-fold lower than the detection limits of both a PCR for the detection of bexA and a nested PCR for Hib (Hib PCR). No H. influenzae, other than Hib or control bacteria, was detected. Linear determination ranged from 10 to 1,000,000 microorganisms per reaction mixture using real-time turbidimetry. We evaluated the Hib LAMP assay using a set of 52 randomly selected cerebrospinal fluid (CSF) specimens obtained from children with suspected meningitis. For comparison, the CSF specimens were tested using a conventional Hib PCR assay. Hib was detected in 30 samples using LAMP and in 22 samples using the Hib PCR assay. The Hib PCR showed a clinical sensitivity of 73.3% and a clinical specificity of 100% relative to the Hib LAMP assay. These results suggest that further development and evaluation of the Hib LAMP will enhance the global diagnostic capability for Hib detection.

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Section: Bacterialmentioning

confidence: 99%

Loop-Mediated Isothermal Amplification Assay for Detection of Haemophilus influenzae Type b in Cerebrospinal Fluid

et al. 2011

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“…1). Computer analysis revealed an extensive similarity (45% identity) between this ORF product and a CDP-ribitol pyrophosphorylase from Haemophilus influenzae, the gene for which is located some distance from the obg homolog in this organism (12,47).…”

Section: Resultsmentioning

confidence: 99%

Molecular cloning and characterization of the obg gene of Streptomyces griseus in relation to the onset of morphological differentiation

1997

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Morphological differentiation in microorganisms is usually accompanied by a decrease in intracellular GTP pool size, as has been demonstrated in bacillaceae, streptomycetaceae, and yeasts. The obg gene, which codes for a GTP-binding protein belonging to the GTPase superfamily of proteins, was cloned from Streptomyces griseus IFO13189. The gene is located just downstream of the genes for ribosomal proteins L21 and L27, encoded a protein of 478 amino acids (51 kDa), and possessed three consensus motifs which confer GTPbinding ability; Obg protein expressed in Escherichia coli bound GTP, as demonstrated using a UV crosslinking method. Introduction of multiple copies of obg into wild-type S. griseus suppressed aerial mycelium development in cells on solid media. However, no effect on streptomycin production was detected, indicating that Obg is involved in the regulation of the onset of morphological but not physiological differentiation. Multiple copies of obg also suppressed submerged spore formation in liquid culture. Southern hybridization studies indicated that genes homologous to obg exist widely in streptomycetes, and an obg homolog was successfully cloned from S. coelicolor A3(2). We propose that by monitoring the intracellular GTP pool size, the Obg protein is involved in sensing changes in the nutritional environment leading ultimately to morphological differentiation.During evolution, organisms have learned to respond to certain environmental changes by producing specialized cell types. The signal initiating this development must persist for some time before the cells commit themselves irreversibly to differentiate. Several genera of bacteria, including Bacillus, Clostridium, Sporosarcina, Myxococcus, and Streptomyces, produce spores when they encounter adverse environmental conditions such as nutrient deficiency (reviewed by Freese and Heinze [14]). A distinguishing characteristic of species of the genus Streptomyces is their ability to form an aerial mycelium from a substrate mycelium when cultured on solid media, eventually leading to the formation of spores by the synchronous and regularly spaced septation of the aerial mycelium (for reviews, see references 5, 6, 7, and 18). Only a limited number of Streptomyces species such as S. griseus can produce spores (submerged spores) when cultured in liquid medium (26).Our laboratory (34,35,39) and the laboratory of Freese (15,30,40) have demonstrated that a decrease in GTP pool size correlates with the initiation of morphological differentiation in Bacillus subtilis and Streptomyces spp. Thus, these organisms can be induced to differentiate in nutritionally rich media, in which cells normally do not sporulate, (i) when the GTP pool size is reduced by the addition of decoyinine, an inhibitor of GMP synthesis; (ii) by the depletion of guanine in guaninerequiring auxotrophic mutants; or (iii) by provoking the stringent response in which ppGpp, a potent inhibitor of IMP dehydrogenase, accumulates. Although the role of GTP pool size variations is at present uncle...

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“…In encapsulated H. influenzae strains, the genes for the production of the polysaccharide capsules are organized in a capsulation (cap) locus, which consists of three different functional regions (11,13). Regions I and III are common to all capsular types and contain genes necessary for transport and process of the capsular material, while region II contains serotype-specific biosynthesis genes (7,10,18,19,25).…”

mentioning

confidence: 99%

Genetic Characterization of the Capsulation Locus of Haemophilus influenzae Serotype e

et al. 2010

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Region II of the Haemophilus influenzae Type b capsulation locus as involved in serotype‐specific polysaccharide synthesis

Cited by 55 publications

References 41 publications

Loop-Mediated Isothermal Amplification Assay for Detection of Haemophilus influenzae Type b in Cerebrospinal Fluid

Loop-Mediated Isothermal Amplification Assay for Detection of Haemophilus influenzae Type b in Cerebrospinal Fluid

Molecular cloning and characterization of the obg gene of Streptomyces griseus in relation to the onset of morphological differentiation

Genetic Characterization of the Capsulation Locus of Haemophilus influenzae Serotype e

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