AIMS--To evaluate the use of a duplex polymerase chain reaction (PCR) assay for the simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis in clinical samples. METHODS--Genital swab specimens were obtained from both China (203 swabs) and Hong Kong (202 swabs). N gonorrhoeae and C trachomatis were detected in each specimen with a number of tests including enzyme immunoassays (IDEIA) and PCR assays using both single and double primer pairs. The primer pair for N gonorrhoeae was derived from the cppB gene on its cryptic plasmid and the PCR product was 390 base pairs long. For C trachomatis, the PCR product was 473 base pairs long, resulting from amplification of a sequence in the common 7.4 kilobase plasmid present in all serovars. For N gonorrhoeae, PCR results were also compared with those obtained by culture and Gram9s smear of the discharges. RESULTS--For the 203 specimens collected in China, similar numbers of positive results (177) were obtained by both Gonozyme and duplex PCR for the detection of N gonorrhoeae. No discrepant results were found among the cultured specimens when Gonozyme and duplex PCR were compared. C trachomatis was detected in 47 specimens by duplex PCR, but was detected in only 28 by IDEIA. Of the 202 Hong Kong specimens, 46 were positive for N gonorrhoeae, detected by both Gonozyme and duplex PCR; 34 were positive for C trachomatis, 25 of which were detected by IDEIA and the remainder by duplex PCR. CONCLUSIONS--The duplex PCR assay is a satisfactory diagnostic tool for the simultaneous detection of N gonorrhoeae and C trachomatis in clinical swab samples. Further evaluation is suggested.
We have shown previously that cDNAs for the Ml and M2 subunits of ribonucleotide reductase, ornithine decarboxylase (ODC), and p5–8, a 55,000-Dalton protein, hybridize to amplified genomic sequences in a highly hydroxyurea-resistant hamster cell line. We have extended these observations to include two additional, independently isolated, hydroxyurea-resistant cell lines: SC8, a single-step hamster ovary cell line, and KH450, a multistep human myeloid leukemic cell line, have also undergone genomic amplification for sequences homologous to ODC and p5–8 cDNAs. However, neither SC8 nor KH450 contains amplified genomic sequences homologous to an Ml cDNA probe. A panel of mouse-hamster somatic cell hybrids was used to map sequences homologous to Ml, M2, ODC, and 5–8 cDNAs in the hamster genome. The M2, ODC, and p5–8 cDNAs hybridized to DNA fragments that segregated with hamster chromosome 7. In contrast, Ml cDNA hybridized to DNA fragments that segregated with hamster chromosome 3. These data suggest that the genes RRM2, (M2), ODC, and p5–8, but not RRM1 (Ml), are linked and may have been co-amplified in the selection of the hydroxyurea-resistant hamster and human cell lines.
Abstract : The period since the end of the Cold War has witnessed a dramatic growth in the number of multilateral military operations, most loosely linked with the generic term 'peacekeeping.' The overwhelming majority of these operations have taken place under the auspices of the United Nations. They are a reflection of the rebirth of tribal nationalism, spreading religious xenophobia, and the threatened impoverishment and disintegration of Third World nation- states that have slipped their colonial moorings since World War II. As a result, we are witnessing new challenges to the United States, to the regional organizations in which we share membership, and to the United Nations system. This study effort will concentrate on the changing nature of peace operations, their likely impact on the U.S. military, and ways to improve and enhance the capabilities of various organizations to successfully complete future peace operations. The terms of reference will include the changing international security environment, the strengths and weaknesses of the United Nations and NATO in coping with existing security issues, and possible remedial actions. Policy proposals and recommendations include: a need to develop military doctrine that provides operational guidance for the broad range of activities that fall under the term 'peace operations', the urgent requirement for development of various types of unified command and control arrangements to meet future contingency operations; and the desirability of including civilian components in early stages of operational planning.
Abstract Asgard archaea is a recently proposed superphylum currently comprised of five recognised phyla: Lokiarchaeota, Thorarchaeota, Odinarchaeota, Heimdallarchaeota and Helarchaeota. Members of this group have been identified based on culture-independent approaches with several metagenome-assembled genomes (MAGs) reconstructed to date. However, most of these genomes consist of several relatively small contigs, and, until recently, no complete Asgard archaea genome is yet available. Large scale phylogenetic analyses suggest that Asgard archaea represent the closest archaeal relatives of eukaryotes. In addition, members of this superphylum encode proteins that were originally thought to be specific to eukaryotes, including components of the trafficking machinery, cytoskeleton and endosomal sorting complexes required for transport (ESCRT). Yet, these findings have been questioned on the basis that the genome sequences that underpin them were assembled from metagenomic data, and could have been subjected to contamination and other assembly artefacts. Even though several lines of evidence indicate that the previously reported findings were not affected by these issues, having access to high-quality and preferentially fully closed Asgard archaea genomes is needed to definitively close this debate. Current long-read sequencing technologies such as Oxford Nanopore allow the generation of long reads in a high-throughput manner making them suitable for their use in metagenomics. Although the use of long reads is still limited in this field, recent analyses have shown that it is feasible to obtain complete or near-complete genomes of abundant members of mock communities and metagenomes of various level of complexity. Here, we show that long read metagenomics can be successfully applied to obtain near-complete genomes of low-abundant members of complex communities from sediment samples. We were able to reconstruct six MAGs from different Lokiarchaeota lineages that show high completeness and low fragmentation, with one of them being a near-complete genome only consisting of three contigs. Our analyses confirm that the eukaryote-like features previously associated with Lokiarchaeota are not the result of contamination or assembly artefacts, and can indeed be found in the newly reconstructed genomes.
Under the auspices of the U.S. Department of State, the Ford Foundation, Georgetown University, and the African-American Institute, more than 75 scholars and other specialists convened at the Shoreham Hotel, Washington, D.C., to exchange views on problems of political and social change in francophone Africa, and to discuss them with a much wider audience of government officials and diplomats from Africa, Western Europe, Canada, and the United States. The programme, the first of its kind ever held in the United States, was organised and directed by Dr William H. Lewis of Georgetown University.
(thirteen 0.60-in. diam hydroclones in parallel) for installation with the HRT replacement circulating pump were completed. Mixed oxides of U : Th = 0.08 : 1 and all have low yield stresses of 0.02 to 0.05 lb/sq ft compared to 0.2 to 1.0 lb/sq ft for normal Th-U or Th oxides of 1.5 to 2.5 micron mean diameter. The rates of uranium anion exchange from solutions containing between 0.025 and 0.20 M sulfate were measured and apparent uranium diffusion coefficients between 1.2 x 10/sup -7/ cm/sup 2//sec and 1.6 x 10/sup -7/ cm/sup 2//sec were calculated. In bench scale studies, the Darex reference flowsheet was successfully applied to stainless steel-clad UO/sub 2/ fuels (Yankee Atomic) and to aluminumuranium foreign reactor fuels. The corrosion of titanium A-55 was measured in the vapor and liquid phases of a modified boiling Thorex dissolvent (13 M HNO/sub 3/, 0.04 M F/sup -/, 0.1 M H/sub 3/BO/sub 3/) containing 0.0, 0.5, and 1.0 M thorium from dissolved Consolidated Edison pellets and the maximum corrosion rate was 0.6 mils/ month. Siliceous filter cakes resulting from the filtration of Darex solvent extraction feed solutions through porous metal filter elements were easily washed to a uranium loss of 0.1% in the discarded cake. A run with an acid-deficient Darex-Redox feed containing soluble silica resulted in uranium losses higher by a factor of 20 than those previously obtained in the same column with a standard Redox feed. Batch leaching of sheared pieces, 1/2 in. to 5 in. long, of PWR reject UO/sub 2/ pellets clad with stainless steel, 0.40 in. o.d. with 0.10 in. wall, in boiling 10 M HNO/sub 3/ (173% excess) was completed in 70 to 245 min. Dissolution test runs of Zr-2 in fused salt made at approximately 700 ction prod- C under identical conditions except for HF feed rate resulted in dissolution rates of 1.87 and 2.68 mg/min-sq cm for 2.5 and 6.0 lb/hr HF feed rate, respectively. Purex and TBP-25 evaporated wastes were calcined at 900 to 1000 ction prod- C resulting in solid wastes which had densities of 0.77 to 0.83 and 0.40 to 0.45 g/cc, respectively. (For preceding period see CF-59-4-47.) (auth)
William H. Lewis is adjunct fellow of preventive diplomacy at the Center for Strategic and International Studies and a member of Mediterranean Quarterly's editorial advisory board.
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