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The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the closest massive satellite galaxies of the Milky Way. They are probably on their first passage on an infalling orbit towards our Galaxy1and trace the continuing dynamics of the Local Group2. Recent measurements of a high mass for the LMC (Mhalo≈ 1011.1–11.4M⊙)3–6imply that the LMC should host a Magellanic Corona: a collisionally ionized, warm-hot gaseous halo at the virial temperature (105.3–5.5K) initially extending out to the virial radius (100–130 kiloparsecs (kpc)). Such a corona would have shaped the formation of the Magellanic Stream7, a tidal gas structure extending over 200° across the sky2,8,9that is bringing in metal-poor gas to the Milky Way10. Here we show evidence for this Magellanic Corona with a potential direct detection in highly ionized oxygen (O+5) and indirectly by means of triply ionized carbon and silicon, seen in ultraviolet (UV) absorption towards background quasars. We find that the Magellanic Corona is part of a pervasive multiphase Magellanic circumgalactic medium (CGM) seen in many ionization states with a declining projected radial profile out to at least 35 kpc from the LMC and a total ionized CGM mass of log10(MH II,CGM/M⊙) ≈ 9.1 ± 0.2. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic group and its nested evolution with the Local Group.

The interstellar medium (ISM) comprises gases at different temperatures and densities, including ionized, atomic and molecular species, and dust particles1. The neutral ISM is dominated by neutral hydrogen2and has ionization fractions of up to eight per cent3. The concentration of chemical elements heavier than helium (metallicity) spans orders of magnitudes in Galactic stars4, because they formed at different times. However, the gas in the vicinity of the Sun is assumed to be well mixed and to have a solar metallicity in traditional chemical evolution models5. The ISM chemical abundances can be accurately measured with ultraviolet absorption-line spectroscopy. However, the effects of dust depletion6–9—which removes part of the metals from the observable gaseous phase and incorporates it into solid grains—have prevented, until recently, a deeper investigation of the ISM metallicity. Here we report the dust-corrected metallicity of the neutral ISM measured towards 25 stars in our Galaxy. We find large variations in metallicity over a factor of ten (with an average of 55 ± 7 per cent solar metallicity and a standard deviation of 0.28 dex), including many regions of low metallicity, down to about 17 per cent solar metallicity and possibly below. Pristine gas falling onto the Galactic disk in the form of high-velocity clouds can cause the observed chemical inhomogeneities on scales of tens of parsecs. Our results suggest that this low-metallicity accreting gas does not efficiently mix into the ISM, which may help us understand metallicity deviations in nearby coeval stars.

More than 150 years ago William Morton successfully used diethyl ether as general anaesthesia. Advances in anaesthesia have made many new surgical techniques possible, and mortality directly attributable to anaesthesia [...]

Reports of neoplasia in captive reptiles are becoming more frequent; however, there is still scarce knowledge of the occurrence of neoplasia in wild reptiles. A wild black rat snake (Pantherophis alleghaniensis) was presented to the Zoological Medicine service of the University of Georgia’s Veterinary Teaching Hospital with a 3 cm in diameter solid mandibular mass that was partially ulcerated. Radiographically, the mass was radiopaque with small bone spicules and partial osteolysis of the adjacent mandible. Histologic examination of the mass revealed a neoplasm composed of cuboidal to polygonal cells arranged in islands, anastomosing cords, and trabeculae of pseudostratified epithelium with a palisading peripheral layer of densely packed columnar cells with cytoplasmic clearing. The neoplastic tissue was separated from the mesenchyme by a prominent band of fine collagen. Neoplastic cells were positive for cytokeratin and negative for smooth muscle actin. Electron microscopy highlighted the presence of tonofilaments and microvilli. These findings led to the diagnosis of ameloblastoma, an odontogenic epithelial tumor known to occur in humans and most veterinary species.

ABSTRACTNew vaccines targeting meningococci expressing serogroup B polysaccharide have been developed, with some being licensed in Europe. Coverage depends on the distribution of disease-associated genotypes, which may vary by age. It is well established that a small number of hyperinvasive lineages account for most disease, and these lineages are associated with particular antigens, including vaccine candidates. A collection of 4,048 representative meningococcal disease isolates from 18 European countries, collected over a 3-year period, were characterized by multilocus sequence typing (MLST). Age data were available for 3,147 isolates. The proportions of hyperinvasive lineages, identified as particular clonal complexes (ccs) by MLST, differed among age groups. Subjects <1 year of age experienced lower risk of sequence type 11 (ST-11) cc, ST-32 cc, and ST-269 cc disease and higher risk of disease due to unassigned STs, 1- to 4-year-olds experienced lower risk of ST-11 cc and ST-32 cc disease, 5- to 14-year-olds were less likely to experience ST-11 cc and ST-269 cc disease, and =25-year-olds were more likely to experience disease due to less common ccs and unassigned STs. Younger and older subjects were vulnerable to a more diverse set of genotypes, indicating the more clonal nature of genotypes affecting adolescents and young adults. Knowledge of temporal and spatial diversity and the dynamics of meningococcal populations is essential for disease control by vaccines, as coverage is lineage specific. The nonrandom age distribution of hyperinvasive lineages has consequences for the design and implementation of vaccines, as different variants, or perhaps targets, may be required for different age groups.

ABSTRACTUropathogenic Escherichia coli(UPEC) is the predominant cause of urinary tract infection in both hospital and community settings. The recent emergence of multidrug-resistant clones like the O25b:H4-ST131 lineage represents a significant threat to health, and numerous studies have explored the virulence potential of these organisms. Members of the ST131 clone have been described as having variable carriage of key virulence factors, and it has been suggested that additional unidentified factors contribute to virulence. Here we demonstrated that ST131 isolates have high metabolic potential and biochemical profiles that distinguish them from isolates of many other sequence types (STs). A collection of 300 UPEC isolates recovered in 2007 and 2009 in the Northwest region of England were subjected to metabolic profiling using the Vitek2 Advanced Expert System (AES). Of the 47 tests carried out, 30 gave a positive result with at least one of the 300 isolates examined. ST131 isolates demonstrated significant association with eight tests, including those for peptidase, decarboxylase, and alkalinization activity. Metabolic activity also correlated with antibiotic susceptibility profiles, with resistant organisms displaying the highest metabolic potential. This is the first comprehensive study of metabolic potential in the ST131 lineage, and we suggest that high metabolic potential may have contributed to the fitness of members of the ST131 clone, which are able to exploit the available nutrients in both the intestinal and urinary tract environments.

We present an analysis of ionization and metal enrichment in the Magellanic Stream (MS), the nearest gaseous tidal stream, using Hubble Space Telescope/STIS and FUSE ultraviolet spectroscopy of two background active galactic nuclei. The targets are NGC 7469, lying directly behind the MS with log N(H I)MS = 18.63 +- 0.03(stat) +- 0.08(syst), and Mrk 335, lying 24.deg7 away with log N(H I)MS = 16.67 +- 0.05. For NGC 7469, we include optical spectroscopy from VLT/UVES. In both sight lines, the MS is detected in low-ion (O I, C II, C III, Si II, Si III, Al II, Ca II) and high-ion (O VI, C IV, Si IV) absorption. Toward NGC 7469, we measure an MS oxygen abundance [O/H]MS = [O I/H I] = -1.00 +- 0.05(stat) +- 0.08(syst), supporting the view that the Stream originates in the Small Magellanic Cloud rather than the Large Magellanic Cloud. We use CLOUDY to model the low-ion phase of the Stream as a photoionized plasma using the observed Si III/Si II and C III/C II ratios. Toward Mrk 335, this yields an ionization parameter between log U = -3.45 and -3.15, a gas density log (n H/cm-3) between -2.51 and -2.21, and a hydrogen ionization fraction of 98.9%-99.5%. Toward NGC 7469, we derive sub-solar abundance ratios for [Si/O], [Fe/O], and [Al/O], indicating the presence of dust in the MS. The high-ion column densities are too large to be explained by photoionization, but also cannot be explained by a single-temperature collisional ionization model (equilibrium or non-equilibrium). This suggests that the high-ion plasma is multi-phase, with an Si IV region, a hotter O VI region, and C IV potentially contributing to each. Summing over the low-ion and high-ion phases, we derive conservative lower limits on the ratio N(total H II)/N(H I) of [?]19 toward NGC 7469 and [?]330 toward Mrk 335, showing that along these two directions the vast majority of the Stream has been ionized. The presence of warm-hot plasma together with the small-scale structure observed at 21 cm provides evidence for an evaporative interaction with the hot Galactic corona. This scenario, predicted by hydrodynamical simulations, suggests that the fate of the MS will be to replenish the Galactic corona with new plasma, rather than to bring neutral fuel to the disk.

ABSTRACTFood-borne salmonellosis is a major manifestation of gastrointestinal disease in humans across the globe. Accurate and rapid identification methods could positively impact the identification of isolates, enhance outbreak investigation, and aid infection control. The SNaPshot multiplex system is a primer extension-based method that enables multiplexing of single nucleotide polymorphisms (SNPs). Here the method has been developed for the identification of five Salmonellaserotypes, commonly detected in the United Kingdom, based on serotype-specific SNPs identified in the multilocus sequence typing (MLST) database of Salmonella enterica. The SNPs, in genes hemD, thrA, purE, and sucA, acted as surrogate markers for S. entericaserovars Typhimurium, Enteritidis, Virchow, Infantis, and Braenderup. The multiplex primer extension assay (MPEA) was conducted in two separate panels and evaluated using 152 Salmonella entericaisolates that were characterized by MLST. The MPEA was shown to be 100% specific and sensitive, within this collection of isolates. The MPEA is a sensitive and specific method for the identification and detection of Salmonellaserotypes based upon SNPs seen in MLST data. The method can be applied in less than 6 h and has the potential to improve patient care and source tracing. The utility of the assay for identification of Salmonellaserotypes directly from clinical specimens and food samples warrants further investigation.

ABSTRACTA total of 88 uropathogenic Escherichia coliisolates, including 68 isolates from urine and 20 isolates from blood, were characterized by multilocus sequence typing (MLST). MLST has identified an important genetic lineage of E. coli, designated sequence type 131 (ST-131), represented by 52 of these isolates, 51 of which were resistant to extended-spectrum cephalosporins. ST-131 appears to be a drug-resistant uropathogenic strain of E. coliresponsible for causing urinary tract infections and bacteremia and is widely disseminated among both community and hospital patients from different geographical areas in the northwest of England. Application of MLST has helped to define the population biology which may underpin the epidemiology of pathogenic E. colistrains. The portability of MLST allows the accurate monitoring of this antibiotic-resistant uropathogenic strain of E. coliand will enhance surveillance for this important group of organisms.

ABSTRACTInfections associated with Neisseria meningitidisare a major public health problem in England, Wales, and Northern Ireland. Currently, over 40% of cases are confirmed directly from clinical specimens using PCR-based methodologies without an organism being isolated. A nested/seminested multilocus sequence typing (MLST) system was developed at the Health Protection Agency Meningococcal Reference Unit to allow strain characterization beyond the serogroup for cases confirmed by PCR only. This system was evaluated on a panel of 20 meningococcus-positive clinical specimens (3 cerebrospinal fluid and 17 blood samples) from different patients containing various concentrations of meningococcal DNA that had corresponding N. meningitidisisolates. In each case, the sequence type generated from the clinical specimens matched that produced from the corresponding N. meningitidisisolate; the sensitivity of the MLST system was determined to be less than 12 genome copies per PCR. The MLST system was then applied to 15 PCR meningococcus-positive specimens (2 cerebrospinal fluid and 13 blood samples), each from a different patient, involved in three case clusters (two serogroup B and one serogroup W135) for which no corresponding N. meningitidisorganisms had been isolated. In each case, an MLST sequence type was generated, allowing the accurate assignment of individual cases within each of the case clusters. In summary, the adaptation of the N. meningitidisMLST to a sensitive nested/seminested format for strain characterization directly from clinical specimens provides an important tool for surveillance and management of meningococcal infection.

We study the physical conditions, elemental abundances, and kinematics of the high-velocity clouds (HVCs) along the sight lines toward active galaxies HE 0226-4110 and PG 0953+414 using Hubble Space Telescope Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer data. No 21 cm H I emission is detected in these clouds, but our observations reveal multiple components of HVC absorption in lines of H I, C II, C III, C IV, O VI, Si II, Si III, and Si IV in both directions. We investigate whether photoionization by the extragalactic background radiation or by escaping Milky Way radiation can explain the observed ionization pattern. We find that photoionization is a good explanation for the C II, C III, Si II, and Si III features but not for the O VI or C IV associated with the HVCs, suggesting that two principal phases exist: a warm (T [?] 104 K), photoionized phase and a hotter (T = 1-3 x 105 K), collisionally ionized phase; the broader line widths of the high ions are consistent with this multiphase hypothesis. The warm HVCs toward HE 0226-4110 have high levels of ionization (97%-99%) and metallicities ([Z/H] between -0.9 and -0.4) close to those in the Magellanic Stream, which lies 11deg away on the sky at similar velocities. These HVCs may well be stripped fragments of the Stream that have been ionized by the pervading radiation field; they have thermal pressures that would place them close to equilibrium in a fully ionized 106 K Galactic corona with nH = 4-9 x 10-5 cm-3 at 50 kpc. The warm HVCs seen at -146 and 125 km s-1 toward PG 0953+414 have [Z/H] = -0.6 +- 0.2 and -0.8 +- 0.2, respectively, suggesting they are not formed from purely Galactic material. A minisurvey of the hot, collisionally ionized HVC components seen here and in five other sight lines finds that in 11/12 cases, the high ions have kinematics and ionic ratios that are consistent with an origin in conductive interfaces, where energy flows into the HVCs from a hot surrounding medium and produces O VI- and C IV-bearing boundary layers. However, the broad absorption wing on the O VI profile toward PG 0953+414 is not completely explained by the interface scenario. This feature may be tracing the outflow of hot gas into the Milky Way halo as part of a Galactic fountain or wind.

High-quality Far Ultraviolet Spectroscopic Explorer (FUSE) observations at 20 km s-1 resolution of interstellar and intergalactic absorption from 910 to 1187 A are presented for the X-ray-bright BL Lac object Mrk 421. These observations are supplemented with FUSE data for the distant halo stars BD +38deg2182 and HD 93521 near the Mrk 421 line of sight, in order to obtain information about the distance to absorbing structures in the Milky Way toward Mrk 421. The FUSE ISM observations provide measures of absorption by O VI and many other species commonly found in warm neutral and warm ionized gas, including H I, C II, C III, O I, N I, N II, Fe II, and Fe III. In this study we consider the O VI absorption between -140 and 165 km s-1 and its relationship to the lower ionization absorption and strong absorption produced by O VII and O VIII at X-ray wavelengths. The O VI absorption extending from -140 to 60 km s-1 is associated with strong low-ionization gas absorption and originates in the Galactic thick disk/halo. This O VI appears to be produced by a combination of processes, including conductive interfaces between warm and hot gas and possibly cooling Galactic fountain gas and hot halo gas bubbles. The O VI absorption extending from 60 to 165 km s-1 has unusual ionization properties in that there is very little associated low-ionization absorption, with the exception of C III. This absorption is not observed toward the two halo stars, implying that it occurs in gas more distant than 3.5 kpc from the Galactic disk. Over the 60-165 km s-1 velocity range, O VI and C III absorption have the same kinematic behavior. The ratio N(O img1.gif)/N(C img2.gif) = 10 +- 3 over the 60-120 km s-1 velocity range. Given the association of O VI with C III, it is unlikely that the high-velocity O VI coexists with the hotter gas responsible for the O VII and O VIII absorption. The O VI positive velocity absorption wing might be tracing cooler gas entrained in a hot Galactic fountain outflow. The O VII and O VIII absorption observed by Chandra and XMM-Newton may trace the hot gas in a highly extended (~100 kpc) Galactic corona or hot gas in the Local Group. The low resolution of the current X-ray observations (~750-900 km s-1) and the kinematical complexity of the O VI absorption along typical lines of sight through the Milky Way halo make it difficult to clearly associate the O VI absorption with that produced by O VII and O VIII. A search for metal lines associated with the Lya absorber at z = 0.01, which is situated in a galactic void, was unsuccessful.

We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high-, intermediate-, and low-ion absorption in high-velocity cloud (HVC) Complex C along the lines of sight toward five active galaxies. Our purpose is to investigate the idea that Complex C is surrounded by an envelope of highly ionized material, arising from the interaction between the cloud and a hot surrounding medium. We measure column densities of high-velocity high-ion absorption and compare the kinematics of low-, intermediate-, and high-ionization gas along the five sight lines. We find that in all five cases, the H I and O VI high-velocity components are centered within 20 km s-1 of one another, with an average displacement of img1.gif = 3 +- 12 km s-1. In those directions where the H I emission extends to more negative velocities (the so-called high-velocity ridge), so does the O VI absorption. The kinematics of Si II is also similar to that of O VI, with img2.gif = 0 +- 15 km s-1. We compare our high-ion column density ratios to the predictions of various models, adjusted to account for both recent updates to the solar elemental abundances and relative elemental abundance ratios in Complex C. Along the PG 1259+593 sight line, we measure N(Si img3.gif)/N(O img4.gif) = 0.10 +- 0.02, N(C img3.gif)/N(O img4.gif) = 0.35img5.gif, and N(N img6.gif)/N(O img4.gif) < 0.07 (3 s). These ratios are inconsistent with collisional ionization equilibrium at one kinetic temperature. Photoionization by the extragalactic background is ruled out as the source of the high ions since the path lengths required would make HVCs unreasonably large; photoionization by radiation from the disk of the Galaxy also appears unlikely since the emerging photons are not energetic enough to produce O VI. By themselves, ionic ratios are insufficient to discriminate between various ionization models, but by considering the absorption kinematics as well, we consider the most likely origin for the highly ionized high-velocity gas to be at the conductive or turbulent interfaces between the neutral/warm ionized components of Complex C and a surrounding hot medium. The presence of interfaces on the surface of HVCs provides indirect evidence for the existence of a hot medium in which the HVCs are immersed. This medium could be a hot (T [?] 106 K) extended Galactic corona or hot gas in the Local Group.

ABSTRACTThe haploid pathogenic yeast Candida glabratais the second most common Candidaspecies isolated from cases of bloodstream infection. The clinical relevance of C. glabratais enhanced by its reduced susceptibility to fluconazole. Despite this, little is known of the epidemiology or population structure of this species. We developed a multilocus sequence typing (MLST) scheme for C. glabrataand used it to fingerprint a geographically diverse collection of 107 clinical isolates and 2 reference strains. Appropriate loci were identified by amplifying and sequencing fragments of the coding regions of 11 C. glabratagenes in 10 unrelated isolates. The 6 most variable loci (FKS, LEU2, NMT1, TRP1, UGP1, and URA3) were sequenced in the collection of 109 isolates. From the 3,345 bp sequenced in each isolate, 81 nucleotide sites were found to be variable. These defined 30 STs among the 109 strains. The technique was validated by comparison with random amplified polymorphic DNA and the complex DNA fingerprinting probes Cg6 and Cg12. MLST identified 5 major clades among the isolates studied. Three of the clades exhibited significant geographical bias. Our data demonstrate for the first time, with such a large geographically diverse strain collection, that distinct genetic clades of C. glabrataprevail in different geographical regions.

We present Hubble Space Telescope Imaging Spectrograph (HST/STIS) and Far Ultraviolet Spectroscopic Explorer (FUSE) observations of high ion interstellar ultraviolet absorption along the sight line to HD 116852. At a distance of 4.8 kpc, HD 116852 is an O9 III star lying in the low Galactic halo, -1.3 kpc from the plane of the Galaxy in the direction l = 304.deg9, b = -16.deg1. The sight line passes underneath the Sagittarius-Carina and the Norma-Centaurus spiral arms. The STIS E140H grating observations provide high-resolution (FWHM [?] 2.7 km s-1) spectra of the resonance doublets of Si IV, C IV, and N V. These data are complemented by medium-resolution (FWHM [?] 20 km s-1) FUSE spectra of O VI. The integrated logarithmic column densities are log N(Si IV) = 13.60 +- 0.02, log N(C IV) = 14.08 +- 0.03, log N(N V) = 13.34img1.gif, and log N(O VI) = 14.28 +- 0.01. We find evidence for three distinct types of highly ionized gas present in the data. First, two narrow absorption components are resolved in the Si IV and C IV profiles, at approximate LSR velocities of -36 and -10 km s-1 . These narrow components appear to be produced in gas associated with the Norma and Sagittarius spiral arms, at approximate z-distances of -1.0 and -0.5 kpc, respectively. The temperature of the gas in these narrow components, as implied by their b-values, suggests that the gas is photoionized. The ratio of C IV to Si IV in these narrow components is low compared to the Galactic average. Second, we detect an intermediate-width component in C IV and Si IV, at 17 km s-1, which we propose could arise at the conductive interface at the boundary between a low column density neutral or weakly ionized cloud and the surrounding hot medium. Finally, a broad collisionally ionized component of gas responsible for producing the smooth N V and O VI profiles is observed; such absorption is also present to a lesser degree in the profiles of Si IV and C IV. The broad O VI absorption is observed at a velocity displaced from the broad C IV component by almost 20 km s-1, an amount large enough to suggest that the two ions may not coexist in the same physical location. If these two ions do exist together, then the ratio N(C IV)/N(O VI) is too low to be consistent with turbulent mixing layer models, but could be explained by radiative cooling or conductive heating models. Combining our results with high resolution observations of four other sight lines from the literature, we find an average C IV component frequency of 1.0 +- 0.25 kpc-1.

A two-step reverse transcriptase TaqMan™ duplex PCR (RT-PCR) assay was developed using the ABI 7700 Sequence Detection System for the detection of enterovirus (EV) and parechovirus type 1 and 2 (PEV) RNA from samples of cerebrospinal fluid (CSF) and throat swabs. Using sequence-specific fluorescent dye labeled probes and continuous ‘real-time’ monitoring, PCR amplified product accumulation was measured. Based on limiting dilutions, the TaqMan™ enterovirus and parechovirus RT-PCR showed an increase of two orders of magnitude compared to cell culture with sensitivity of 100% (7/7) when assessed using enterovirus cell culture positive samples (CSF, TS). The assays were specific for enterovirus and parechovirus and did not amplify a wide selection of virus and bacterial isolates. RNA was amplified from 22 enterovirus serotypes: coxsackie A7, A9, A21; coxsackie B2, B3, B4, B5; echovirus 2, 4, 6, 7, 9, 11, 13, 17, 18, 19, 30, 31; poliovirus types 1, 2, and 3, and parechovirus types 1 and 2. The assay was used to assess the incidence of enterovirus and parechovirus RNA in cell culture negative CSF and throat swab samples (n = 200). An additional 33 (15.9%) enterovirus and 2 (1%) parechovirus were identified as positive by RT-PCR. Also, of 100 CSF samples from suspected cases of meningococcal meningitis submitted for meningococcal PCR testing, 59 (59%) were enterovirus and 2 (2%) parechovirus 1 and 2 were positive by RT-PCR. The TaqMan™ duplex assay offers a more rapid and sensitive alternative to conventional cell culture for the diagnosis of enterovirus and parechovirus infection. Closed tube real-time detection using the ABI Sequence Detection System obviates the need for post-PCR manipulation, which reduces hands on time and eliminates the risk of contamination from amplified PCR product. J. Med. Virol. 67:555–562, 2002. © 2002 Wiley-Liss, Inc.

Quantitative assessment of cytomegalovirus (CMV) infection using the antigenemia test has been used to monitor CMV infection in heart and lung transplant patients enabling a preemptive treatment strategy. However, the method is labour intensive, samples have to be processed within a few hours and requires skilled interpretation. A comparative prospective evaluation of a real-time TaqMan™ CMV quantitative PCR (QPCR) with the CMV antigenemia was undertaken.

In a period where the proportion of culture confirmed cases in the UK has been steadily declining, diagnosis by PCR has been used to increase the number of confirmed cases and provide additional epidemiological data. This report presents a comparative evaluation of the fluorogenic probe‐based 5′ exonuclease assay (Taqman) using the Perkin‐Elmer Applied Biosystems automated sequence detection system 7700 with previously reported polymerase chain reaction enzyme‐linked immunosorbent (PCR ELISA) assays for the detection of meningococcal DNA in CSF, plasma and serum samples. Taqman assays developed were based on the detection of a meningococcal capsular transfer gene (ctrA), the insertion sequence IS1106and the sialytransferase gene (siaD) for serogroup B and C determination and compared with similar assays in a PCR ELISA format. The Taqman ctrAassay was specific for Neisseria meningitidis, however the IS1106assay gave false positive reactions with a number of non‐meningococcal isolates. Sensitivity of the Taqman ctrA, IS1106and siaDassays testing samples from culture‐confirmed cases were 64, 69 and 50%, respectively, compared with 26, 67 and 43% for the corresponding PCR ELISA assays. Improvements to the DNA extraction procedure has increased the sensitivity to 93 and 91% for the TaqMan™ctrAand siaDassays, respectively, compared to culture confirmed cases. Since the introduction of Taqman PCR a 56% increase in laboratory confirmed cases of meningococcal disease has been observed compared to culture only confirmed cases. The developed Taqman assays for the diagnosis of meningococcal disease enables a high throughput, rapid turnaround of samples with considerable reduced risk of contamination.

An effective vaccine for serogroup B meningococci has yet to be developed and attention has turned to subcapsular antigens of the meningococcus as possible vaccine candidates. Iron binding proteins are being studied, with most interest focused on the transferrin binding proteins (TbpA and TbpB) and the ferric binding protein (FbpA). This study describes the purification of lactoferrin binding protein A (LbpA) from two meningococcal strains and assesses the human isotype‐specific serum antibody response to these proteins in patients with proven meningococcal disease due to a range of phenotypes. Overall, fewer than 50% of sera contained IgG that recognised LbpA isolated from either strain and this antibody response was not uniform between the two proteins. There was some evidence that the antibody response varied between meningococcal phenotypes. This study demonstrates that LbpA does not induce a highly cross‐reactive antibody response, indicating that it is unlikely to be an effective vaccine antigen.

Flagellin gene sequence polymorphisms were used to discrimate amongst 53 strains of Campylobacter jejuni and C. coli. The Campylobacter strains were made up of forty-three strains of Campylobacter jejuni and 10 strains of Campylobacter coli. The results were analysed in relation to Penner serotyping. Twenty DNA PCR -RFLP patterns (genotypes) were identified by analysis of Dde I fragment length polymorphisms in flagellin gene (fla A and fla B) polymerase chain reaction (PCR) products. Flagellin gene 13 genotype was a feature of 15% of strains, followed by flagellin gene 8 (9 %). Differences in fragment patterns were observed not only between members of two species, but also between individual strains of the same species. The strains that were non-typable by the Penner serotype were distributed into 6 flagellin gene types.

Subcapsular antigens, including transferrin binding proteins, are being considered as potential vaccines against serogroup B meningococci. This study examined the human isotype antibody responses in cases of meningococcal disease to meningococcal TbpA (transferrin binding protein A) and TbpB (transferrin binding protein B) from two strains (SD and B16B6) expressing high and low molecular mass TbpB respectively. TbpA isolated from both strains were recognised more frequently and higher durable ELISA absorbance values were detected than those detected against TbpB from either strain. These antibody responses to Tbps were independent of the infecting meningococcal strain type. The antibody response to the four proteins was highly variable between individuals and differed significantly against all four antigens. The variability of immune responses to each Tbp from the two strains suggests that a successful vaccine would need to include TbpA and TbpB from a number of strains.

At a time when optimal case ascertainment for meningococcal infection is a high priority, the need for non‐culture case confirmation, in particular by DNA amplification, is seen as being of vital importance to assist contact management and cluster recognition. A solution hybridisation assay with colorimetric microtitre plate detection (polymerase chain reaction‐enzyme‐linked immunosorbent assay (PCR ELISA)) has been developed using the multicopy insertion sequence IS1106which had reportedly achieved a specificity of 100% and was described as being meningococcal specific. This PCR ELISA assay was evaluated on specimens from over 5000 patients at the national Meningococcal Reference Unit (MRU) between late 1995 and early 1997 and was found to be highly sensitive. Insertion sequences, however, are genetically mobile with the ability to spread between species and even genera. During the evaluation period of the IS1106PCR ELISA a number of false positives proved to be caused by organisms other than N. meningitidiswere recorded resulting in the withdrawal of this assay as a front line screening assay for routine confirmation of meningococcal infection.

Components of outer membrane preparations, heated saline extracts, and phenolwater lipopolysaccharide extracts obtained from strains ofCampylobacter jejuni representing seven passive hemagglutination serotypes (Penner serotypes 1–4, 13, 16, and 50) were electrophoresed in sodium dodecyl sulfate-polyacrylamide gels. Tests of gel eluates demonstrated that lipopolysaccharide antigens are involved in serotypingC. jejuni by passive hemagglutination and that other cell surface components have no activity. This finding was confirmed by hemagglutination inhibition. In the typing ofC. jejuni by passive hemagglutination, each serotype is probably defined by the presence of one or more specific lipopolysaccharides. These findings may lead to a clarification of the serotyping nomenclature for those systems that depend on passive hemagglutination. It is recommended that a single internationally agreed numbering system be adopted for lipopolysaccharides derived fromC. jejuni.

Non‐culture diagnosis and serogroup determination of meningococcal infection is important in contact management where vaccination may be possible. A serogroup B and C PCR ELISA assay for the non‐culture diagnosis and serogroup determination has proved invaluable for enhanced epidemiological surveillance and contact management. A polymerase chain reaction assay, based on a restriction fragment length polymorphism in the meningococcal serogroup Y and W135 sialyltransferase (siaD) gene, was developed to enhance the range of non‐culture diagnosis of meningococcal infection from clinical samples. The PCR assay was adapted to an ELISA format incorporating hybridisation with serogroup‐specific Y and W135 oligonucleotide probes. The serogroup‐specific W135 and Y PCR ELISA is a useful addition to currently available serogroup B and C assay for non‐culture diagnosis of meningococcal infection and outbreak investigation.

ABSTRACTThe genetic diversity of porBgenes from meningococcal isolates characterized as serotype 22 was investigated by gene sequencing. This procedure identified seven distinct porBsequences, demonstrating variation in the PorB protein recognized by the serotype 22 monoclonal antibody. This is consistent with the genetic heterogeneity of serotype 22 meningococci reported previously.

O VI absorption is observed in a wide range of astrophysical environments, including the local interstellar medium, the disk and halo of the Milky Way, high-velocity clouds, the Magellanic Clouds, starburst galaxies, the intergalactic medium (IGM), damped Lya systems, and gamma-ray-burst host galaxies. Here, a new compilation of 775 O VI absorbers drawn from the literature is presented, all observed at high resolution (instrumental FWHM [?] 20 km s-1) and covering the redshift range z = 0-3. In galactic environments [log N(H I) [?] 20], the mean O VI column density is shown to be insensitive to metallicity, taking a value log N(O VI) [?] 14.5 for galaxies covering the range -1.6 [?] [O/H] [?] 0. In intergalactic environments [log N(H I) < 17], the mean O VI component column density measured in data sets of similar sensitivity shows only weak evolution between z = 0.2 and z = 2.3, but IGM O VI components are on average almost twice as broad at z = 0.2 than at z = 2.3. The implications of these results on the origin of O VI are discussed. The existence of a characteristic value of log N(O VI) for galactic O VI absorbers, and the lack of evolution in log N(O VI) for intergalactic absorbers, lend support to the "cooling-flow" model of Heckman et al., in which all O VI absorbers are created in regions of initially hot shock-heated plasma that are radiatively cooling through coronal temperatures. These regions could take several forms, including conductive, turbulent, or shocked boundary layers between warm ([?]104 K) clouds and hot ([?]106 K) plasma, although many such layers would have to be intersected by a typical galaxy-halo sight line to build up the characteristic galactic N(O VI). The alternative, widely used model of single-phase photoionization for intergalactic O VI is ruled out by kinematic evidence in the majority of IGM O VI components at low and high redshift.

At a time when optimal case ascertainment for meningococcal infection is a high priority, the need for non-culture case confirmation, in particular by DNA amplification, is seen as being of vital importance to assist contact management and cluster recognition. A solution hybridisation assay with colorimetric microtitre plate detection (polymerase chain reaction-enzyme-linked immunosorbent assay (PCR ELISA)) has been developed using the multicopy insertion sequence IS1106 which had reportedly achieved a specificity of 100% and was described as being meningococcal specific. This PCR ELISA assay was evaluated on specimens from over 5000 patients at the national Meningococcal Reference Unit (MRU) between late 1995 and early 1997 and was found to be highly sensitive. Insertion sequences, however, are genetically mobile with the ability to spread between species and even genera. During the evaluation period of the IS1106 PCR ELISA a number of false positives proved to be caused by organisms other than N. meningitidis were recorded resulting in the withdrawal of this assay as a front line screening assay for routine confirmation of meningococcal infection.

Non-culture diagnosis and serogroup determination of meningococcal infection is important in contact management where vaccination may be possible. A serogroup B and C PCR ELISA assay for the non-culture diagnosis and serogroup determination has proved invaluable for enhanced epidemiological surveillance and contact management. A polymerase chain reaction assay, based on a restriction fragment length polymorphism in the meningococcal serogroup Y and W135 sialyltransferase (siaD) gene, was developed to enhance the range of non-culture diagnosis of meningococcal infection from clinical samples. The PCR assay was adapted to an ELISA format incorporating hybridisation with serogroup-specific Y and W135 oligonucleotide probes. The serogroup-specific W135 and Y PCR ELISA is a useful addition to currently available serogroup B and C assay for non-culture diagnosis of meningococcal infection and outbreak investigation.

A serum-susceptible, guinea-pig chamber-passaged, laboratory strain (BS4 (agar)) of Neisseria gonorrhoeae was converted to serum resistance by incubation with cytidine 5-monophospho-N-acetyl neuraminic acid (CMP-NANA) and examined by electron microscopy after straining with ruthenium-red. In contrast to serum susceptible gonococci incubated without CMP-NANA, the majority (60–70%) of the serum resistant organisms showed a surface accumulation of polysaccharide. This surface polysaccharide was enhanced on all the resistant gonococci after incubation with fresh human serum. Control susceptible gonococci were devoid of the polysaccharide after incubation with heated human serum. Indentical results were obtained with a fresh gonococcal isolate which had lost serum resistance on subculture but wich, in common with 3 other isolates, was restored to serum resistance by incubation with CMP-NANA.

The reactogenicity and immunogenicity of a serogroup A and C meningococcal polysaccharideCRM197 conjugate vaccine was evaluated in 58 infants who received three doses at 2, 3, and 4 months of age. The conjugate vaccine produced few systemic side effects, and local reactions were significantly less common than those produced by the routine vaccinations. The prevaccination geometric mean titers (GMTs) of A and C polysaccharide antibodies were, respectively, 2.8 and 0.6 µg/mL, rising to 21.5 and 38.5 µlmL by 1 month after the third dose (age 5 months) and falling to 3.1 and 2.2 µg/mL by 14 months of age. Prevaccination serum bactericidal titers against 2 serogroup C meningococci strains were < 1/4 in 49 of 52 infants, rising to a GMT of 113082 at 1month after the third dose and falling by age 14 months to a GMT of 1110. Thus, this meningococcal conjugate vaccine proved to be safe and immunogenic, inducing high levels of anti-C polysaccharide antibodies that were bactericidal in young infants.