The intragenus specificities of five molecular diagnostic methods for Neisseria gonorrhoeae were determined. Three assays were considered suboptimal. Molecular detection of N. gonorrhoeae from sites where other Neisseria spp. commonly occur or from any site in low-prevalence settings should be confirmed by a test targeting a different genetic locus.The United Kingdom national guidelines for laboratory diagnosis of Neisseria gonorrhoeae recommend culture of the organism followed by confirmatory tests, which, for most specimens, is highly sensitive and specific. However, the sensitivity of culture may be suboptimal from specimen types such as pharyngeal and rectal swabs and synovial fluids (14, 21). Molecular diagnostic tests may be more appropriate for these sample types.Intra-and interspecies genetic recombination occurs between members of the genus Neisseria and may do so with surprising frequency (6,15). This poses a problem for the specificity of DNA-based diagnostic tests for N. gonorrhoeae, since the detection of a single gonococcus-specific gene that has been acquired by a commensal Neisseria isolate would result in a false-positive laboratory diagnosis. Assays of the highest specificity are required for testing extragenital specimens, in particular pharyngeal specimens, because this site commonly harbors commensal Neisseria and/or Neisseria meningitidis (11, 16).Commercial molecular diagnostic tests for N. gonorrhoeae are designed for use on genital swabs and urine specimens, but some have also been evaluated for their use on extragenital specimens, such as pharyngeal and rectal swabs (17,18,21; H. Young, A. Moyes, and A. McMillan, Abstr. 12th Meet. Int. Soc. Sex. Transm. Dis. Res., abstr. O182, 1997). These studies suggest that, even with these specimen types, molecular methods can provide increased sensitivity compared to culture. However, molecular diagnostic assays for N. gonorrhoeae are usually evaluated during development with few or perhaps even single isolates of each species of Neisseria, so their true specificity within the genus remains unknown. This study evaluated the specificity of three commercial nucleic acid amplification assays and two published PCR assays by using isolates of Neisseria spp. that inhabit the human mucosal membranes.A collection of 104 epidemiologically unrelated isolates from the genus Neisseria was used in this study. The collection consisted of the following: 24 N. gonorrhoeae isolates, including 20 of the proline-requiring, arginine-requiring (not satisfied by ornithine), uracil-requiring (PA o U) auxotype, 10 N. meningitidis isolates, 23 Neisseria cinerea isolates, 6 Neisseria flavescens isolates, 11 Neisseria subflava isolates, 7 Neisseri mucosa isolates, 13 Neisseria lactamica isolates, 8 Neisseria sicca isolates, and 2 Neisseria elongata isolates. Of the nongonococcal isolates, 13 were National Collection of Type Cultures strains and the remaining 67 were originally isolated from a range of body sites: 15 ocular (13 of which were from infants under 1 year of age...

PLATES 160 TO 165(Received for publication, May 25, 1959) ABSTRACT In Hydra adjacent epithelial cells are bound firmly to each other by desmosomes of a type not described in detail hitherto. The most prominent feature of these desmosomes is the presence of a series of parallel lamellae which bridge the intercellular space and connect the two apposed cell surfaces directly. These structures, here termed intercellular attachment lamellae, display two peaks of density about 50 A apart. These dense lines appear in some instances to be continuous with the outer dense components of the plasma unit membranes of the attached cells.The presence of prominent lamellae in intercellular attachments is sufficiently distinctive to deserve special terminology; accordingly, the term septate desmosome is proposed. It is noted that septate desmosomes may have been seen in other animals in instances where published electron micrographs show cross-striations or prominent connections in regions of intercellular attachment.It is suggested that septate desmosomes in Hydra, in addition to binding cells firmly to each other, form barriers to the movement of water into intercellular spaces and thus help to protect the organism's internal environment.Observations on the use of phosphotungstic acid for improving contrast in materials embedded in epoxy resins are also recorded. cializations which have been interpreted as regions of firm cellular attachment (Porter, 1956; SjSstrand, 1954;Selby, 1955;Horstmann and Knoop, 1958;Fawcett, 1958;Odland, 1958). For many tissues this concept supersedes the older idea of a homogeneous intercellular cementing substance binding cells together over their entire area of mutual contact (see yon Recklinghausen, 1862).I t is notable that specialized cellular attachments have been described in detail to date only in vertebrate tissues. The purpose of this communication is to report the presence in Hydra of intercellular attachments which differ in fine structure from the types previously recognized.The fine structure of Hydra attachments is set forth in detail and is compared with intercellular attachments described from other tissues. Attempts are made to interpret this special morphology in terms of function.Before proceeding to the descriptive portion of this paper a brief review of the history of our knowledge 343

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Flaherty, and the Board and Scholars Group of Interfaith Funders, as well as the funding from Interfaith Funders' member institutions for support of this research. We also thank Jim Ron, Elisabeth Wood, Bob Bellah, Ann Swidler, Robert Wuthnow and participants in Princeton University's Religion and Culture Workshop, and anonymous reviewers for critical comments.

The development of bile canaliculi and the sequence of appearance of pericanalicular bodies has been explored by electron microscopy. The first bile canaliculi appear on about the thirteenth embryonic day in close association with linear attachment zones between adjacent hepatic cells. These canaliculi are formed by only two apposed cell surfaces and the configuration of a central biliary lumen bounded by 4-5 contiguous cells described classically as typical for developing mammalian liver is not apparent until day 16 or 17. The enlarged biliary spaces apparently arise as separate vesicles or saccules which subsequently elongate into tubules and interconnect. Evidence obtained in this study supports the concept that terminal bile ductules develop by direct transformation of tubular channels lined by hepatic cells under the influence of periportal connective tissue. Pericanalicular bodies develop in association with an hypertrophied Golgi zone. The sequence of appearance is: multivesicular bodies, microbodies, typical lysosomes. There is no evidence from this study that microbodies arc related to differentiating mitochondria but the chronology of appearance suggests a close relationship to lysosomes.