Porphyry copper deposits, all showing similar geological characteristics, occur in Tertiary and older orogenic-volcanic belts around the w•orld. Recent isotope and fluidinclusion studies have shown that in a number of deposits the development of the characteristic ore alteration pattern, at some stage, involved the interaction of meteoric ground waters with saline fluids evolved from a magma. A fluid dynamic model is proposed for porphyry copper emplacement which focuses on the interaction of a buoyant low-salinity magmatic vapor plume with surrounding ground water. As the magmatic vapor rises and cools, high-salinity liquid condenses in a two-phase plume core, drains under gravity, and is diverted to vertical lower salinity stream lines tangential to the two-phase core boundary. Cool ground water is entrained into the rising fluid, giving rise to a buoyant dispersion plume. The potassic core and inner part of the phyllic alteration envelope of the porphyry copper system is regarded, in compliance with isotopic data, as the remnant imprint of the plume on the ground-water regime.Although the model may be modified to a ground-water source for the "magmatic fluid," the authors favor an orthomaglnatic hypothesis by which w, ater and essential ore components are derived from a cooling magma column convecting lighter, more volatile components from a deeper level. The temperature profile of the steady-state plume is calculated using empirical data for permeability and heat input from the active Wairakei and Broadlands geothermal systems. Chemical implications of the physical model are in accord with the observed alteration-mineralization patterns and available high-temperature solubility data. Metals enter the system as hydroxyl or chloride complexes in the low-salinity magmatic gas precipitating in response to ground-water entrainment, temperature, and wall-rock induced pH and ]:o2 variations. Some transport analogies are tentatively drawn with the observed chemistry of volcanic gases.The plume model also provides an interpretation of the characteristics of the deep portion of active geothermal systems and may be extended to other ore-forming systems such as epithermal veins and massive sulfides. In the majority of such hydrothermal systems, if ore formation occurred below around 350øC, the magmatic input may be marked by the then predominant entrained ground-water component.

These findings underscore the virulence of human CoV-OC43 in elderly populations and confirm that cross-reactivity to antibody against nucleocapsid proteins from these viruses must be considered when interpreting serological tests for SARS-CoV.

Mycobacterium pseudoshottsii sp. nov., a slowly growing chromogenic species isolated from Chesapeake Bay striped bass (Morone saxatilis) A group of slowly growing photochromogenic mycobacteria was isolated from Chesapeake Bay striped bass (Morone saxatilis) during an epizootic of mycobacteriosis. Growth characteristics, acid-fastness and 16S rRNA gene sequencing results were consistent with those of the genus Mycobacterium. Biochemical reactions, growth characteristics and mycolic acid profiles (HPLC) resembled those of Mycobacterium shottsii, a non-pigmented mycobacterium also isolated during the same epizootic. Sequencing of the 16S rRNA genes, the gene encoding the exported repeated protein (erp) and the gene encoding the 65 kDa heat-shock protein (hsp65) and restriction enzyme analysis of the hsp65 gene demonstrated that this group of isolates is unique. Insertion sequences associated with Mycobacterium ulcerans, IS2404 and IS2606, were detected by PCR. These isolates could be differentiated from other slowly growing pigmented mycobacteria by their inability to grow at 37 6C, production of niacin and urease, absence of nitrate reductase, negative Tween 80 hydrolysis and resistance to isoniazid (1 mg ml "1 ), p-nitrobenzoic acid, thiacetazone and thiophene-2-carboxylic hydrazide. On the basis of this polyphasic study, it is proposed that these isolates represent a novel species, Mycobacterium pseudoshottsii sp. nov. The type strain, L15 T , has been deposited in the American Type Culture Collection as ATCC BAA-883 T and the National Collection of Type Cultures (UK) as NCTC 13318 T .

We assessed the ability of an in-house database, consisting of 111 hsp65 sequences from putative and valid Mycobacterium species or described groups, to identify 689 mycobacterial clinical isolates from 35 species or groups. A preliminary assessment indicated that hsp65 sequencing confirmed the identification of 79.4% of the isolates from the 32 species examined, including all Mycobacterium tuberculosis complex isolates, all isolates from 13 other species, and 95.6% of all M. avium-M. intracellulare complex isolates. Identification discrepancies were most frequently encountered with isolates submitted as M. chelonae, M. fortuitum, M. gordonae, M. scrofulaceum, and M. terrae. Reexamination of isolates with discrepant identifications confirmed that hsp65 identifications were correct in a further 40 isolates. This brought the overall agreement between hsp65 sequencing and the other identification methods to 85.2%. The remaining 102 isolates had sequence matches below our acceptance criterion, had nondifferential sequence matches between two or more species, were identified by 16S rRNA sequencing as a putative taxonomic group not contained in our database, or were identified by hsp65 and 16S rRNA gene sequencing as a species not in our biochemical test database or had conflicting identifications. Therefore, to incorporate the unconfirmed isolates it was necessary to create 29 additional entries in our hsp65 identification database: 18 associated with valid species, 7 indicating unique sequences not associated with valid or putative species or groups, and 4 associated with unique, but currently described taxonomic groups. Confidence in the hsp65 sequence identification of a clinical isolate is best when sequence matches of 100% occur, but our data indicate that correct identifications can be confidently made when unambiguous matches exceeding 97% occur, but are dependent on the completeness of the database. Our study indicates that for hsp65 sequencing to be an effective means for identifying mycobacteria a comprehensive database must be constructed. hsp65 sequencing has the advantage of being more rapid and less expensive than biochemical test panels, uses a single set of reagents to identify both rapid-and slow-growing mycobacteria, and can provide a more definitive identification. (56) described, using separate gene regions, the successful identification of mycobacteria by using restriction digest analysis of amplified hsp65 fragments (hsp65 PRA). The technique, as described by Telenti et al., has been frequently investigated as a means of identifying mycobacteria and, although hsp65 PRA is an accepted means of identifying mycobacteria, it does have functional limitations, some of which have been addressed (3,6,10,11,13,15,19,39,40,43,49,55,69,71). Kapur et al. (23), recognizing the limitations of hsp65 PRA and the potential advantage of generating direct unambiguous data, were the first to sequence the hsp65 amplicon generated by the Telenti primers as a means for identifying mycobacteria. This technique has sin...