Inkjet-printed point-of-care immunoassay on a nanoscale polymer brush enables subpicomolar detection of analytes in blood

The ELISA is the mainstay for sensitive and quantitative detection of protein analytes. Despite its utility, ELISA is time-consuming, resource-intensive, and infrastructure-dependent, limiting its availability in resource-limited regions. Here, we describe a self-contained immunoassay platform (the "D4 assay") that converts the sandwich immunoassay into a point-of-care test (POCT). The D4 assay is fabricated by inkjet printing assay reagents as microarrays on nanoscale polymer brushes on glass chips, so that all reagents are "on-chip," and these chips show durable storage stability without cold storage. The D4 assay can interrogate multiple analytes from a drop of blood, is compatible with a smartphone detector, and displays analytical figures of merit that are comparable to standard laboratory-based ELISA in whole blood. These attributes of the D4 POCT have the potential to democratize access to high-performance immunoassays in resource-limited settings without sacrificing their performance.

Plasmonic biosensors

The unique optical properties of plasmon resonant nanostructures enable exploration of nanoscale environments using relatively simple optical characterization techniques. For this reason, the field of plasmonics continues to garner the attention of the biosensing community. Biosensors based on propagating surface plasmon resonances (SPRs) in films are the most well-recognized plasmonic biosensors, but there is great potential for the new, developing technologies to surpass the robustness and popularity of film-based SPR sensing. This review surveys the current plasmonic biosensor landscape with emphasis on the basic operating principles of each plasmonic sensing technique and the practical considerations when developing a sensing platform with the various techniques. The 'gold standard' film SPR technique is reviewed briefly, but special emphasis is devoted to the up-and-coming localized surface plasmon resonance and plasmonically coupled sensor technology.

Nanoparticle-Film Plasmon Ruler Interrogated with Transmission Visible Spectroscopy

The widespread use of plasmonic nanorulers (PNRs) in sensing platforms has been plagued by technical challenges associated with the development of methods to fabricate precisely controlled nanostructures with high yield and characterize them with high throughput. We have previously shown that creating PNRs in a nanoparticle-film (NP-film) format enables the fabrication of an extremely large population of uniform PNRs with 100% yield using a self-assembly approach, which facilitates high-throughput PNR characterization using ensemble spectroscopic measurements and eliminates the need for expensive microscopy systems required by many other PNR platforms. We expand upon this prior work herein, showing that the NP-film PNR can be made compatible with aqueous sensing studies by adapting it for use in a transmission localized surface plasmon resonance spectroscopy format, where the coupled NP-film resonance responsible for the PNR signal is directly probed using an extinction measurement from a standard spectrophotometer. We designed slide holders that fit inside standard spectrophotometer cuvettes and position NP-film samples so that the coupled NP-film resonance can be detected in a collinear optical configuration. Once the NP-film PNR samples are cuvette-compatible, it is straightforward to calibrate the PNR in aqueous solution and use it to characterize dynamic, angstrom-scale distance changes resulting from pH-induced swelling of polyelectrolyte (PE) spacer layers as thin as 1 PE layer and also of a self-assembled monolayer of an amine-terminated alkanethiol. This development is an important step toward making PNR sensors more user-friendly and encouraging their widespread use in various sensing schemes.

Plasmonic waveguide modes of film-coupled metallic nanocubes

A metallic nanoparticle positioned over a metal film offers great advantages as a highly controllable system relevant for probing field-enhancement and other plasmonic effects. Because the size and shape of the gap between the nanoparticle and film can be controlled to subnanometer precision using relatively simple, bottom-up fabrication approaches, the film-coupled nanoparticle geometry has recently been applied to enhancing optical fields, accessing the quantum regime of plasmonics, and the design of surfaces with controlled reflectance. In the present work, we examine the plasmon modes associated with a silver nanocube positioned above a silver or gold film, separated by an organic, dielectric spacer layer. The film-coupled nanocube is of particular interest due to the formation of waveguide cavity-like modes between the nanocube and film. These modes impart distinctive scattering characteristics to the system that can be used in the creation of controlled reflectance surfaces and other applications. We perform both experimental spectroscopy and numerical simulations of individual nanocubes positioned over a metal film, finding excellent agreement between experiment and simulation. The waveguide mode description serves as a starting point to explain the optical properties observed.

Plasmon ruler with angstrom length resolution

We demonstrate a plasmon nanoruler using a coupled film nanoparticle (film-NP) format that is well-suited for investigating the sensitivity extremes of plasmonic coupling. Because it is relatively straightforward to functionalize bulk surface plasmon supporting films, such as gold, we are able to precisely control plasmonic gap dimensions by creating ultrathin molecular spacer layers on the gold films, on top of which we immobilize plasmon resonant nanoparticles (NPs). Each immobilized NP becomes coupled to the underlying film and functions as a plasmon nanoruler, exhibiting a distance-dependent resonance red shift in its peak plasmon wavelength as it approaches the film. Due to the uniformity of response from the film-NPs to separation distance, we are able to use extinction and scattering measurements from ensembles of film-NPs to characterize the coupling effect over a series of very short separation distances-ranging from 5 to 20 Å-and combine these measurements with similar data from larger separation distances extending out to 27 nm. We find that the film-NP plasmon nanoruler is extremely sensitive at very short film-NP separation distances, yielding spectral shifts as large as 5 nm for every 1 Å change in separation distance. The film-NP coupling at extremely small spacings is so uniform and reliable that we are able to usefully probe gap dimensions where the classical Drude model of the conducting electrons in the metals is no longer descriptive; for gap sizes smaller than a few nanometers, either quantum or semiclassical models of the carrier response must be employed to predict the observed wavelength shifts. We find that, despite the limitations, large field enhancements and extreme sensitivity persist down to even the smallest gap sizes.

Probing the ultimate limits of plasmonic enhancement

Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.

Probing dynamically tunable localized surface plasmon resonances of film-coupled nanoparticles by evanescent wave excitation

The localized surface plasmon resonance (LSPR) spectrum associated with a gold nanoparticle (NP) coupled to a gold film exhibits extreme sensitivity to the nanogap region where the fields are tightly localized. The LSPR of an ensemble of film-coupled NPs can be observed using an illumination scheme similar to that used to excite the surface plasmon resonance (SPR) of a thin metallic film; however, in the present system, the light is used to probe the highly sensitive distance-dependent LSPR of the gaps between NPs and film rather than the delocalized SPR of the film. We show that the SPR and LSPR spectral contributions can be readily distinguished, and we compare the sensitivities of both modes to displacements in the average gap between a collection of NPs and the gold film. The distance by which the NPs are suspended in solution above the gold film is fixed via a thin molecular spacer layer and can be further modulated by subjecting the NPs to a quasistatic electric field. The observed LSPR spectral shifts triggered by the applied voltage can be correlated with angstrom scale displacements of the NPs, suggesting the potential for chip-scale or flow-cell plasmonic nanoruler devices with extreme sensitivity.

Gold nanoparticles on polarizable surfaces as Raman scattering antennas

Surface plasmons supported by metal nanoparticles are perturbed by coupling to a surface that is polarizable. Coupling results in enhancement of near fields and may increase the scattering efficiency of radiative modes. In this study, we investigate the Rayleigh and Raman scattering properties of gold nanoparticles functionalized with cyanine deposited on silicon and quartz wafers and on gold thin films. Dark-field scattering images display red shifting of the gold nanoparticle plasmon resonance and doughnut-shaped scattering patterns when particles are deposited on silicon or on a gold film. The imaged radiation patterns and individual particle spectra reveal that the polarizable substrates control both the orientation and brightness of the radiative modes. Comparison with simulation indicates that, in a particle-surface system with a fixed junction width, plasmon band shifts are controlled quantitatively by the permittivity of the wafer or the film. Surface-enhanced resonance Raman scattering (SERRS) spectra and images are collected from cyanine on particles on gold films. SERRS images of the particles on gold films are doughnut-shaped as are their Rayleigh images, indicating that the SERRS is controlled by the polarization of plasmons in the antenna nanostructures. Near-field enhancement and radiative efficiency of the antenna are sufficient to enable Raman scattering cyanines to function as gap field probes. Through collective interpretation of individual particle Rayleigh spectra and spectral simulations, the geometric basis for small observed variations in the wavelength and intensity of plasmon resonant scattering from individual antenna on the three surfaces is explained.

Leveraging nanoscale plasmonic modes to achieve reproducible enhancement of light

The strongly enhanced and localized optical fields that occur within the gaps between metallic nanostructures can be leveraged for a wide range of functionality in nanophotonic and optical metamaterial applications. Here, we introduce a means of precise control over these nanoscale gaps through the application of a molecular spacer layer that is self-assembled onto a gold film, upon which gold nanoparticles (NPs) are deposited electrostatically. Simulations using a three-dimensional finite element model and measurements from single NPs confirm that the gaps formed by this process, between the NP and the gold film, are highly reproducible transducers of surface-enhanced resonant Raman scattering. With a spacer layer of roughly 1.6 nm, all NPs exhibit a strong Raman signal that decays rapidly as the spacer layer is increased.

Isolation and diversity of actinomycetes in the chesapeake bay

Chesapeake Bay was investigated as a source of actinomycetes to screen for production of novel bioactive compounds. The presence of relatively large populations of actinoplanetes (chemotype II/D actinomycetes) in Chesapeake Bay sediment samples indicates that it is an eminently suitable ecosystem from which to isolate actinomycetes for screening programs. Actinomycetes were isolated from sediment samples collected in Chesapeake Bay with an isolation medium containing nalidixic acid, which proved to be more effective than heat pretreatment of samples. Actinomycete counts ranged from a high of 1.4 x 10 to a low of 1.8 x 10 CFU/ml of sediment. Actinomycetes constituted 0.15 to 8.63% of the culturable microbial community. The majority of isolates from the eight stations studied were actinoplanetes (i.e., chemotype II/D), and 249 of these isolates were obtained in a total of 298 actinomycete isolates. Antimicrobial activity profiles indicated that diverse populations of actinoplanetes were present at each station. DNA hybridization studies showed considerable diversity among isolates between stations, but indicated that actinoplanete strains making up populations at nearby stations were more similar to each other than to populations sampled at distant stations. The diversity of actinoplanetes and the ease with which these organisms were isolated from Chesapeake Bay sediments make this a useful source of these actinomycetes.

A versatile diffractive maskless lithography for single-shot and serial microfabrication

We demonstrate a diffractive maskless lithographic system that is capable of rapidly performing both serial and single-shot micropatterning. Utilizing the diffractive properties of phase holograms displayed on a spatial light modulator, arbitrary intensity distributions were produced to form two and three dimensional micropatterns/structures in a variety of substrates. A straightforward graphical user interface was implemented to allow users to load templates and change patterning modes within the span of a few minutes. A minimum resolution of approximately 700 nm is demonstrated for both patterning modes, which compares favorably to the 232 nm resolution limit predicted by the Rayleigh criterion. The presented method is rapid and adaptable, allowing for the parallel fabrication of microstructures in photoresist as well as the fabrication of protein microstructures that retain functional activity.

Distance-dependent plasmon resonant coupling between a gold nanoparticle and gold film

We present an experimental analysis of the plasmonic scattering properties of gold nanoparticles controllably placed nanometers away from a gold metal film. We show that the spectral response of this system results from the interplay between the localized plasmon resonance of the nanoparticle and the surface plasmon polaritons of the gold film, as previously predicted by theoretical studies. In addition, we report that the metal film induces a polarization to the single nanoparticle light scattering, resulting in a doughnut-shaped point spread function when imaged in the far-field. Both the spectral response and the polarization effects are highly sensitive to the nanoparticle-film separation distance. Such a system shows promise in potential biometrology and diagnostic devices.

Seawater Mg/Ca controls polymorph mineralogy of microbial CaCO3: a potential proxy for calcite-aragonite seas in Precambrian time

A previously published hydrothermal brine-river water mixing model driven by ocean crust production suggests that the molar Mg/Ca ratio of seawater (mMg/Ca(sw)) has varied significantly (approximately 1.0-5.2) over Precambrian time, resulting in six intervals of aragonite-favouring seas (mMg/Ca(sw) > 2) and five intervals of calcite-favouring seas (mMg/Ca(sw) < 2) since the Late Archaean. To evaluate the viability of microbial carbonates as mineralogical proxy for Precambrian calcite-aragonite seas, calcifying microbial marine biofilms were cultured in experimental seawaters formulated over the range of Mg/Ca ratios believed to have characterized Precambrian seawater. Biofilms cultured in experimental aragonite seawater (mMg/Ca(sw) = 5.2) precipitated primarily aragonite with lesser amounts of high-Mg calcite (mMg/Ca(calcite) = 0.16), while biofilms cultured in experimental calcite seawater (mMg/Ca(sw) = 1.5) precipitated exclusively lower magnesian calcite (mMg/Ca(calcite) = 0.06). Furthermore, Mg/Ca(calcite )varied proportionally with Mg/Ca(sw). This nearly abiotic mineralogical response of the biofilm CaCO3 to altered Mg/Ca(sw) is consistent with the assertion that biofilm calcification proceeds more through the elevation of , via metabolic removal of CO2 and/or H+, than through the elevation of Ca2+, which would alter the Mg/Ca ratio of the biofilm's calcifying fluid causing its pattern of CaCO3 polymorph precipitation (aragonite vs. calcite; Mg-incorporation in calcite) to deviate from that of abiotic calcification. If previous assertions are correct that the physicochemical properties of Precambrian seawater were such that Mg/Ca(sw) was the primary variable influencing CaCO3 polymorph mineralogy, then the observed response of the biofilms' CaCO3 polymorph mineralogy to variations in Mg/Ca(sw), combined with the ubiquity of such microbial carbonates in Precambrian strata, suggests that the original polymorph mineralogy and Mg/Ca(calcite )of well-preserved microbial carbonates may be an archive of calcite-aragonite seas throughout Precambrian time. These results invite a systematic evaluation of microbial carbonate primary mineralogy to empirically constrain Precambrian seawater Mg/Ca.

Direct Electrochemical and Spectroscopic Assessment of Heme Integrity in Multiphoton Photo-Cross-Linked Cytochrome c Structures

Multiphoton excitation (MPE) lithography offers an effective, biocompatible technique by which three-dimensional architectures comprised of proteins, enzymes, and other relevant materials may be fabricated for use in biological studies involving cellular signal transduction and neuronal networking. We present a series of studies designed to investigate the integrity of cytochrome c (cyt c) photo-cross-linked via MPE. Specifically, we have used electrochemical methods and surface-enhanced Raman spectroscopy (SERS) to determine whether photo-cross-linked cyt c retains its well-characterized Fe(II/III) heme redox activity. Cyt c is observed to retain its native FeII/III electron-transfer properties, as the apparent electron-transfer rate constant, k0ET, for cyt c photo-cross-linked onto an indium-doped tin oxide (ITO) substrate was 8.4 +/- 0.2 s-1, on the same order of magnitude as literature values though somewhat slower than other immobilized cyt c studies, most likely due to unoptimized entrapment in the photo-cross-linked matrix. SERS data reveals peaks corresponding to vibrational modes of an intact porphyrin ring with the Fe center intact. Cyt c has also been shown to demonstrate peroxidase-like activity, and we have evaluated the turnover rate of H2O2 at photo-cross-linked matrices relative to that at adsorbed monolayers of cyt c on glass substrates. The photo-cross-linked cyt c samples demonstrate apparent Michaelis-Menten parameters of Vm = 0.34 fmol/s and kcat/Km on the order of 104 s-1 M-1, in agreement with previously published results for aqueous cyt c. Fluorescence data obtained for mediated H2O2 turnover also indicated enzymatic activity specifically at photo-cross-linked cyt c structures.

Enzyme−Nanoparticle Functionalization of Three-Dimensional Protein Scaffolds

Various surface modification techniques have been developed for patterning functional biomolecules in two dimensions, allowing enzymes, antibodies, and other compounds to be localized for applications in bioanalysis and bioengineering. Here, we report a strategy for extending high-resolution patterning of biomolecules to three dimensions. In this approach, three-dimensional protein scaffolds are created by a direct-write process in which multiphoton excitation promotes photochemical cross-linking of protein molecules from aqueous solution within specified volume elements. After scaffold fabrication, protein microstructures are functionalized with enzyme-gold nanoparticle conjugates via a targeting process based in part on electrostatic attraction between the low-isoelectric-point enzyme and the microstructure, fabricated from high-isoelectric-point proteins. High signal-to-background ratios (approximately 20:1) are demonstrated for fluorescent product streams created by dephosphorylation of the fluorogenic compound, fluorescein diphosphate, at microstructures decorated with alkaline phosphatase-gold nanoparticle conjugates. We also demonstrate feasibility for using such structures to quantify substrate concentrations in flowing streams with low-micromolar detection limits and to create sensor suites based on both enzyme-nanoparticle functionalization and intrinsic enzymatic activity of protein scaffolds. These topographically complex sensors and dosing sources have potential applications in microfluidics, sensor array fabrication, and real-time chemical modification of cell culture environments.

Direct-Write Fabrication of Functional Protein Matrixes Using a Low-Cost Q-Switched Laser

We report the use of an inexpensive, small, and "turn-key" Q-switched 532-nm Nd:YAG laser as a source for nonlinear, direct-write protein microfabrication. In this approach, microJoule pulses (pulse widths, approximately 600 ps) are focused using high numerical aperture optics to submicrometer focal spots, creating instantaneous intensities great enough to promote multiphoton excitation of a photosensitizer and subsequent intermolecular cross-linking of protein molecules. By scanning the femtoliter focal volume through reagent solution, extended protein-based structures can be fabricated with precise, three-dimensional topographies. As with earlier studies using a femtosecond titanium:sapphire laser costing more than 100K, physically robust and chemically responsive microstructures can be fashioned rapidly with feature sizes smaller than 0.5 microm, and cross-linking can be achieved using both biologically benign sensitizers (e.g., flavins) and by using the proteins themselves to sensitize cross-linking. We demonstrate in situ fabrication to corral neurite outgrowth and show the ability to functionalize avidin structures with biotinylated reagents, an approach that enables chemical sensing to be performed in specified microenvironments. Characterization of this inexpensive, low-power source will greatly broaden access to direct-write protein microfabrication.

Microfabrication of Three-Dimensional Bioelectronic Architectures

The functionality and structural diversity of biological macromolecules has motivated efforts to exploit proteins and DNA as templates for synthesis of electronic architectures. Although such materials offer promise for numerous applications in the fabrication of cellular interfaces, biosensors, and nanoelectronics, identification of techniques for positioning and ordering bioelectronic components into useful patterns capable of sophisticated function has presented a major challenge. Here, we describe the fabrication of electronic materials using biomolecular scaffolds that can be constructed with precisely defined topographies. In this approach, a tightly focused pulsed laser beam capable of promoting protein photo-cross-linking in specified femtoliter volume elements is scanned within a protein solution, creating biomolecular matrices that either remain in integral contact with a support surface or extend as free-standing structures through solution, tethered at their ends. Once fabricated, specific protein scaffolds can be selectively metallized via targeted deposition and growth of metal nanoparticles, yielding high-conductivity bioelectronic materials. This aqueous fabrication strategy opens new opportunities for creating electronic materials in chemically sensitive environments and may offer a general approach for creating microscopically defined inorganic landscapes.

Sediment microbes of deep-sea bioherms on the northwest shelf of Australia

The northwest shelf of Australia is a region with known petroleum reserves. Recent geological investigations have revealed carbonate knolls postulated to be of biological origin. Sediment microbial populations at three sites on the northwest shelf, Pee Shoal, Mermaid Reef, and Scott Reef, were investigated for the presence of hydrocarbon-degrading bacteria. From two sampling trips, 246 bacterial strains were purified, and 182 of these strains displayed preferential growth on hydrocarbon-selective media. Strains were tested for nutrient specificity using single hydrocarbon fermentations. Metabolic profiles were constructed using biochemical testing, fatty acid analysis, and metabolic rate experiments. 16S rRNA gene sequence analysis of four strains identified these strains as members of the genera Sphingomonas, Bacillus, and Microbacterium, and one strain as a member of the alpha-Proteobacteria. The potential of these strains as bioindicators of hydrocarbon pollutants or for bioremediation in marine environments is discussed.

Entry of Vibrio harveyi and Vibrio fischeri into the viable but nonculturable state

AIMS

Physiological responses of marine luminous bacteria, Vibrio harveyi (ATCC 14216) and V. fischeri (UM1373) to nutrient-limited normal strength (35 ppt iso-osmolarity) and low (10 ppt hypo-osmolarity) salinity conditions were determined.

METHODS AND RESULTS

Plate counts, direct viable counts, actively respiring cell counts, nucleoid-containing cell counts, and total counts were determined. Vibrio harveyi incubated at 22 degrees C in nutrient-limited artificial seawater (ASW) became nonculturable after approximately 62 and 45 d in microcosms of 35 ppt and 10 ppt ASW, respectively. In contrast, V. fischeri became nonculturable at approximately 55 and 31 d in similar microcosms. Recovery of both culturability and luminescence of cells in the viable but nonculturable state was achieved by addition of nutrient broth or nutrient broth supplemented with a carbon source, including luminescence-stimulating compounds. Temperature upshift from 22 degrees C to 30 degrees C or 37 degrees C did not result in recovery from nonculturability.

CONCLUSIONS

The study confirms entry of V. harveyi and V. fischeri into the viable but nonculturable state under low-nutrient conditions and demonstrates nutrient-dependent resuscitation from this state.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study confirms loss of luminescence of V. harveyi and V. fischeri on entry into the viable but nonculturable state and suggests that enumeration of luminescent cells in water samples may be a rapid method to deduce the nutrient status of a water sample.

Detection and phylogenetic analysis of novel crenarchaeote and euryarchaeote 16S ribosomal RNA gene sequences from a Great Barrier Reef sponge

The presence of Archaea in the Great Barrier Reef marine sponge Rhopaloeides odorabile was investigated by 16S ribosomal RNA community analysis of total DNA extracted from the sponge tissue. The 16S rRNA gene sequences corresponding to group I crenarchaeotes and group II euryarchaeotes were recovered from R. odorabile tissue. The location of archaeal cells within the sponge tissue was investigated using fluorescently labeled oligonucleotide probes. The presence of Archaea was confirmed within all regions of the sponge tissue from R. odorabile, with a significantly higher number of archaeal cells located in the pinacoderm than the mesohyl region. This is the first report of euryarchaeaotes associated with marine sponges.

Chromium accumulation by two Streptomyces spp. isolated from riverine sediments

Strains designated R22 and R25, isolated from Salí River sediments, Argentina, were highly resistant to chromium. These strains were shown by 16S rRNA sequencing studies to be Streptomyces spp.; this affiliation was consistent with morphological and chemical characteristics. Growth of strains R22 and R25 in medium containing 100 mg l(-1) chromate was reduced by only 23% and 34%, respectively, compared with growth in medium without added chromium. Streptomyces sp. strains R22 and R25 both accumulated chromium with yields of 10.0 and 5.6 mg Cr g(-1) of dry weight, respectively, and a chromate concentration of 50 mg ml(-1). Cell fractionation studies with strain R22 showed that the great majority of the chromium were associated with the cell wall fraction. Streptomyces strains R22 and R25 may have applications in bioremediation of chromium contamination.

Phylogenetic diversity of bacteria associated with the marine sponge Rhopaloeides odorabile

Molecular techniques were employed to document the microbial diversity associated with the marine sponge Rhopaloeides odorabile. The phylogenetic affiliation of sponge-associated bacteria was assessed by 16S rRNA sequencing of cloned DNA fragments. Fluorescence in situ hybridization (FISH) was used to confirm the presence of the predominant groups indicated by 16S rDNA analysis. The community structure was extremely diverse with representatives of the Actinobacteria, low-G+C gram-positive bacteria, the beta- and gamma-subdivisions of the Proteobacteria, Cytophaga/Flavobacterium, green sulfur bacteria, green nonsulfur bacteria, planctomycetes, and other sequence types with no known close relatives. FISH probes revealed the spatial location of these bacteria within the sponge tissue, in some cases suggesting possible symbiotic functions. The high proportion of 16S rRNA sequences derived from novel actinomycetes is good evidence for the presence of an indigenous marine actinomycete assemblage in R. odorabile. High microbial diversity was inferred from low duplication of clones in a library with 70 representatives. Determining the phylogenetic affiliation of sponge-associated microorganisms by 16S rRNA analysis facilitated the rational selection of culture media and isolation conditions to target specific groups of well-represented bacteria for laboratory culture. Novel media incorporating sponge extracts were used to isolate bacteria not previously recovered from this sponge.

The effects of copper on the microbial community of a coral reef sponge

Marine sponges often harbour communities of symbiotic microorganisms that fulfil necessary functions for the well-being of their hosts. Microbial communities associated with the sponge Rhopaloeides odorabile were used as bioindicators for sublethal cupric ion (Cu2+) stress. A combined strategy incorporating molecular, cultivation and electron microscopy techniques was adopted to monitor changes in microbial diversity. The total density of sponge-associated bacteria and counts of the predominant cultivated symbiont (alpha-proteobacterium strain NW001) were significantly reduced in response to Cu2+ concentrations of 1.7 microg l(-1) and above after 14 days of exposure. The number of operational taxonomic units (OTUs) detected by restriction fragment length polymorphism (RFLP) decreased by 64% in sponges exposed to 223 microg l(-1) Cu2+ for 48 h and by 46% in sponges exposed to 19.4 microg l(-1) Cu2+ for 14 days. Electron microscopy was used to identify 17 predominant bacterial morphotypes, composing 47% of the total observed cells in control sponges. A reduction in the proportion of these morphotypes to 25% of observed cells was evident in sponges exposed to a Cu2+ concentration of 19.4 microg l(-1). Although the abundance of most morphotypes decreased under Cu2+ stress, three morphotypes were not reduced in numbers and a single morpho-type actually increased in abundance. Bacterial numbers, as detected using fluorescence in situ hybridization (FISH), decreased significantly after 48 h exposure to 19.4 microg l(-1) Cu2+. Archaea, which are normally prolific in R. odorabile, were not detected after exposure to a Cu2+ concentration of 19.4 microg l(-1) for 14 days, indicating that many of the microorganisms associated with R. odorabile are sensitive to free copper. Sponges exposed to a Cu2+ concentration of 223 microg l(-1) became highly necrosed after 48 h and accumulated 142 +/- 18 mg kg(-1) copper, whereas sponges exposed to 19.4 microg l(-1) Cu2+ accumulated 306 +/- 15 mg kg(-1) copper after 14 days without apoptosis or mortality. Not only do sponges have potential for monitoring elevated concentrations of heavy metals but also examining changes in their microbial symbionts is a novel and sensitive bioindicator for the assessment of pollution on important microbial communities.

Use of a chiA probe for detection of chitinase genes in bacteria from the Chesapeake Bay(1)

PCR primers specific for the chiA gene were designed by alignment and selection of highly conserved regions of chiA sequences from Serratia marcescens, Alteromonas sp., Bacillus circulans and Aeromonas caviae. These primers were used to amplify a 225 bp fragment of the chiA gene from Vibrio harveyi to produce a chiA gene probe. The chiA PCR primers and probe were used to detect the presence of the chiA gene in an assemblage of 53 reference strains and gave consistent results. Selected chiA fragments amplified by PCR were cloned and sequenced from nine known strains and from Chesapeake Bay isolates 6d and 11d. This confirmed the specificity and utility of the primers for detection of chiA-positive environmental strains. Over 1000 bacterial isolates from Chesapeake Bay water samples were tested for the presence of the chiA gene which was found to be present in 5-41% (average 21%) of the culturable bacterial community. The approach developed in this study was valuable for isolation and enumeration of chiA-positive bacteria in environmental samples.

Cloning and sequence analysis of the mercury resistance operon of Streptomyces sp. Strain CHR28 reveals a novel putative second regulatory gene

A DNA library of pRJ28, a large linear plasmid encoding mercury resistance, was constructed, and the mercury resistance genes were cloned. The 5,921-bp sequence was analyzed and showed a high degree of similarity to the Streptomyces lividans 1326 mercury resistance operon. Genes merR, merT, merP, and orfIV were found in a similar order and in a single transcription unit. merA and merB were found to be transcribed in the opposite direction to genes merR, merT, merP, and orfIV, as in S. lividans 1326. A novel putative regulatory gene, orfX, was found 22 bp downstream of merA. orfX encodes a 137-amino acid protein with a potential helix-turn-helix motif in the N-terminal domain, characteristic of the MerR family of transcriptional regulators. Transcriptional studies showed that orfX is cotranscribed with merA and merB. It is hypothesized that orfX plays a role in the regulation of the mercury resistance operon, probably by binding at the MerR operator site.

Interspecific transfer of Streptomyces giant linear plasmids in sterile amended soil microcosms

The interspecific transfer of two giant linear plasmids was investigated in sterile soil microcosms. Plasmids pRJ3L (322 kb) and pRJ28 (330 kb), both encoding mercury resistance, were successfully transferred in amended soil microcosms from their streptomycete hosts, the isolates CHR3 and CHR28, respectively, to a plasmidless and mercury-sensitive strain, Streptomyces lividans TK24. Transconjugants of S. lividans TK24 were first observed after 2 to 3 days of incubation at 30 degrees C, which corresponded to the time taken for the formation of mycelia in soil. Transfer frequencies were 4.8 x 10(-4) and 3.6 x 10(-5) CFU/donor genome for pRJ3L and pRJ28, respectively. Transconjugants were analyzed by pulsed-field gel electrophoresis for the presence of plasmids, and plasmid identity was confirmed by restriction digests. Total genomic DNA digests confirmed that transconjugants were S. lividans TK24. The mercury resistance genes were shown to be on the plasmid in the transconjugants by hybridization analysis and were still functional. This is the first demonstration of transfer of giant linear plasmids in sterile soil microcosms. Giant linear plasmids were detected in many Streptomyces spp. isolated from mercury-contaminated sediments from Boston Harbor (United States), Townsville Harbor (Australia), and the Sali River (Tucuman, Argentina). Mercury resistance genes were shown to be present on some of these plasmids. Our findings that giant linear plasmids can be transferred between Streptomyces spp. and are common in environmental Streptomyces isolates suggest that these plasmids are important in gene transfer between streptomycetes in the environment.

A proposal for the reclassification of Bdellovibrio stolpii and Bdellovibrio starrii into a new genus, Bacteriovorax gen. nov. as Bacteriovorax stolpii comb. nov. and Bacteriovorax starrii comb. nov., respectively

Bdellovibrios are unique bacteria with the ability to prey upon a wide variety of susceptible Gram-negative bacteria. Micro-organisms exhibiting this trait have been included in the genus Bdellovibrio despite their isolation from diverse habitats and relatively unstudied taxonomic relatedness. In this study, 16S rDNA sequences were compared from known terrestrial Bdellovibrio species, Bdellovibrio bacteriovorus 100T, Bdellovibrio stolpii Uki2T and Bdellovibrio starrii A3.12T in order to study their phylogenetic relationship. The two sequences from B. stolpii Uki2T and B. starrii A3.12T were 90.0% similar to each other but exhibited only 81.7% and 81.2% similarity, respectively to B. bacteriovorus 100T. Phylogenetic analysis indicated that B. bacteriovorus 100T clustered in a separate clade from B. starrii A3.12T and B. stolpii Uki2T, demonstrating only a distant relationship between B. bacteriovorus 100T and the other two recognized type species. DNA-DNA hybridization experiments also demonstrated <4% hybridization between these three species. On the basis of the results obtained from the phylogenetic analysis and DNA-DNA hybridization studies, it is proposed that B. stolpii Uki2T and B. starrii A3.12T should be transferred to a new genus, Bacteriovorax gen. nov. as Bacteriovorax stolpii comb. nov. and Bacteriovorax starrii comb. nov., respectively. It is also proposed that the type species for the new genus Bacteriovorax should be Bacteriovorax stolpii comb. nov.

Mercury resistance is encoded by transferable giant linear plasmids in two chesapeake bay Streptomyces strains

The Streptomyces strains CHR3 and CHR28, isolated from the Baltimore Inner Harbor, contained two and one, respectively, giant linear plasmids which carry terminally bound proteins. The plasmids pRJ3L (322 kb), from CHR3, and pRJ28 (330 kb), from CHR28, carry genes homologous to the previously characterized chromosomal Streptomyces lividans 66 operon encoding resistance against mercuric compounds. Both plasmids are transmissible (without any detectable rearrangement) to the chloramphenicol-resistant S. lividans TK24 strain lacking plasmids and carrying a chromosomal deletion of the mer operon. S. lividans TK24 conjugants harboring pRJ3L or pRJ28 exhibited profiles of mercury resistance to mercuric compounds similar to those of Streptomyces strains CHR3 and CHR28.

Article

Peracetic acid (Pa) is now being used for totally chlorine-free delignification and bleaching of wood pulps. During the process, metals desorb from the pulp fibers into the aqueous solution. Of the relevant metals in bleaching systems, cobalt(II) and vanadium(V) are the most potent in wastefully decomposing Pa to O2. In the present study, radical scavenging by N,N'-(5-nitro-1,3-phenylene)-bisglutaramide (GAMID) indicates that free-radical mechanisms are operative. Kinetic data support a free-radical decomposition mechanism previously described for Co(II). A similar type of mechanism, involving VO(OH)2(aq) and VO(OH)3(aq), is postulated to partially explain catalysis by vanadium.Key words: peracetic acid, peroxymonosulfuric acid, transition metals, free radicals, acetoxy radical, peracetoxy radical.

Mercury-resistant actinomycetes from the Chesapeake Bay

Two actinomycete strains, CHR3 and CHR28, were isolated from metal-contaminated sediments from Baltimore Inner Harbor. The isolates were classified as Streptomyces spp. Agar diffusion assays showed both isolates to be resistant to mercuric chloride and phenylmercuric acetate. Hybridization experiments indicated that genes homologous to the mercuric reductase and organomercurial lyase of Streptomyces lividans 1326 were present in strains CHR3 and CHR28. Strain CHR28 grew at both low and high salt concentrations; however, strain CHR3 showed enhanced growth in the presence of salt, evidence of its habitat being marine or estuarine sediment.

Distribution of sewage indicated by Clostridium perfringens at a deep-water disposal site after cessation of sewage disposal

Clostridium perfringens, a marker of domestic sewage contamination, was enumerated in sediment samples obtained from the vicinity of the 106-Mile Site 1 month and 1 year after cessation of sewage disposal at this site. C. perfringens counts in sediments collected at the disposal site and from stations 26 nautical miles (ca. 48 km) and 50 nautical miles (ca. 92 km) to the southwest of the site were, in general, more than 10-fold higher than counts from an uncontaminated reference site. C. perfringens counts at the disposal site were not significantly different between 1992 and 1993, suggesting that sewage sludge had remained in the benthic environment at this site. At stations where C. perfringens counts were elevated (i.e., stations other than the reference station), counts were generally higher in the top 1 cm and decreased down to 5 cm. In some cases, C. perfringens counts in the bottom 4 or 5 cm showed a trend of higher counts in 1993 than in 1992, suggesting bioturbation. We conclude that widespread sludge contamination of the benthic environment has persisted for at least 1 year after cessation of ocean sewage disposal at the 106-Mile Site.

Effects of sunlight on bacteriophage viability and structure

Current estimates of viral abundance in natural waters rely on direct counts of virus-like particles (VLPs), using either transmission or epifluorescence microscopy. Direct counts of VLPs, while useful in studies of viral ecology, do not indicate whether the observed VLPs are capable of infection and/or replication. Rapid decay in bacteriophage viability under environmental conditions has been observed. However, it has not been firmly established whether there is a corresponding degradation of the virus particles. To address this question, viable and direct counts were carried out employing two Chesapeake Bay bacteriophages in experimental microcosms incubated for 56 h at two depths in the York River estuary. Viruses incubated in situ in microcosms at the surface yielded decay rates in full sunlight of 0.11 and 0.06 h-1 for CB 38 phi and CB 7 phi, respectively. The number of infective particles in microcosms in the dark and at a depth of 1 m was not significantly different from laboratory controls, with decay rates averaging 0.052 h-1 for CB 38 phi and 0.037 h-1 for CB 7 phi. Direct counts of bacteriophages decreased in teh estuarine microcosms, albeit only at a rate of 0.028 h-1, and were independent of treatment. Destruction of virus particles is concluded to be a process separate from loss of infectivity. It is also concluded that strong sunlight affects the viability of bacteriophages in surface waters, with the result that direct counts of VLPs overestimate the number of bacteriophage capable of both infection and replication. However, in deeper waters, where solar radiation is not a significant factor, direct counts should more accurately estimate numbers of viable bacteriophage.

Distribution of Vibrio vulnificus in the Chesapeake Bay

Vibrio vulnificus is a potentially lethal human pathogen capable of producing septicemia in susceptible persons. Disease is almost always associated with consumption of seafood, particularly raw oysters, or with exposure of wounds to seawater. An oligonucleotide DNA probe (V. vulnificus alkaline phosphatase-labeled DNA probe [VVAP]), previously shown to be highly specific for V. vulnificus, was used to enumerate this species in environmental samples collected from the Chesapeake Bay between April 1991 and December 1992. Total aerobic, heterotrophic, culturable bacteria were enumerated by plate counts on nonselective medium. The number of V. vulnificus organisms was determined by colony lifts of spread plates for subsequent hybridization with VVAP. V. vulnificus was not detected in any samples collected during February and March (water temperature of < 8 degrees C) but was found in 80% of the water samples collected during May, July, September, and December (water temperature of > 8 degrees C), with concentrations ranging from 3.0 x 10(1) to 2.1 x 10(2)/ml (ca. 8% of the total culturable heterotrophic bacteria). In a multiple regression analysis, increased V. vulnificus concentrations were correlated with lower salinities and with isolation from samples collected closer to the bottom. Isolation from oysters was demonstrable when water temperatures were 7.6 degrees C, with concentrations ranging from 1.0 x 10(3) to 4.7 x 10(4)/g (ca. 12% of total culturable bacteria). In samples collected in May and July, V. vulnificus was identified in seven of seven plankton samples and four of nine sediment samples. Our data demonstrate that V. vulnificus is a widespread and important component of the bacterial population of the Chesapeake Bay, with counts that are comparable to those reported from the Gulf of Mexico.

Decrease in culturability of Vibrio cholerae caused by glucose

The culturability of Vibrio cholerae O1 serotype Inaba strain 569B was decreased by the addition of glucose to cell suspensions in starvation media. A similar effect was observed with sucrose, maltose, and fructose. We term this inhibitory effect glucose shock. It was not observed with arabinose or xylose or with carboxylates, such as acetate and pyruvate. No acidification of the medium occurred in the presence of these carbohydrates. Glucose shock was prevented by the addition of nitrogen or phosphorus sources. In the presence of phosphate, the bacterium produced formic acid from glucose. The phenomenon of glucose shock was also observed in V. cholerae O1 serotype Inaba strain RIMD 2203082 but not in strain RIMD 2203088 (O1 Inaba), IID 936 (O1 Ogawa), or RIMD 2214034 (non-O1). The culturability of Escherichia coli, Enterobacter aerogenes, and Listonella anguillarum did not decrease in starvation media with added glucose. Hence, the phenomenon should have ecological significance in determining the distribution of bacteria in marine ecosystems in situations where carbohydrates are abundant, but nitrogen and phosphorus are limiting.

Temperature-induced recovery of Vibrio cholerae from the viable but nonculturable state: growth or resuscitation?

Vibrio cholerae cells were incubated at 4 degrees C in nutrient-limited artificial seawater (ASW) microcosms. Plate counts declined from 8 x 10(5) to less than 2 c.f.u. ml-1 in about 23 d. When samples of microcosms were shifted to 30 degrees C, plate counts increased to 2.2 x 10(5) c.f.u. ml-1 in 72 h. An experiment was performed to determine whether culturable cells obtained after temperature upshifts were the result of 'resuscitation', or outgrowth, of nonculturable cells or of cell division and growth of the few culturable cells that remained in samples. Prior to temperature upshift, samples from the microcosms were diluted 10- and 100-fold in filter-sterilized (0.1 microns) ASW from the microcosms. Undiluted, 1/10, and 1/100 diluted samples recovered culturability to about 2.2 x 10(5) c.f.u. ml-1 within 72 h of temperature upshift. If resuscitation of nonculturable cells had occurred, the resultant number of culturable cells in diluted samples would have been 1/10 and 1/100 that of undiluted samples, respectively. In microcosms where plate counts had declined to less than 1 c.f.u. ml-1, 1/100 diluted samples did not regain culturability, i.e. no culturable cells remained from which growth could occur. Our conclusions are that in the experiments reported here, recovery of culturable cells on temperature upshifts resulted from growth and that there were no growth-inhibiting factors in the spent growth medium, supported by the finding that about 10(2) recovered V. cholerae cells ml-1 inoculated into filter-sterilized microcosm ASW grew to about 6.2 x 10(5) c.f.u. ml-1 in 24 h, confirming that V. cholerae is capable of significant growth in ASW.

Isolation of a Vibrio cholerae transposon-mutant with an altered viable but nonculturable response

We have isolated more than 2500 mutants of Vibrio cholerae by using transposon mutagenesis. Mutants were screened under low nutrient conditions in artificial seawater for an altered viable but nonculturable response, compared to the wild-type. Mutant JR09H1 entered the viable but nonculturable state more rapidly than the wild-type at both 25 degrees C and 4 degrees C.

A gene for the enterotoxin zonula occludens toxin is present in Vibrio mimicus and Vibrio cholerae O139

The presence of the zonula occludens toxin (ZOT) gene, which encodes an enterotoxin produced by serotype O1 strains of the pathogenic bacterium, Vibrio cholerae, in addition to cholera toxin, was investigated in selected strains of V. mimicus and the new pandemic V. cholerae non-O1 serotype O139. The zot gene was detected by polymerase chain reaction (PCR) amplification, using sets of primers based on the sequence of the V. cholerae O1 zot sequence. PCR amplification of genomic DNAs of both cholera toxin gene (ctx) positive and ctx- strains of V. mimicus detected the presence of zot gene. An AccI-EcoRV V. cholerae zot gene fragment designed to overlap PCR products was used as a probe. Southern hybridization studies confirmed that the PCR fragments from V. mimicus and V. cholerae O139 were strongly homologous to the V. cholerae O1 zot gene. The zot gene was found with 3 of 5 strains of V. mimicus of which only one strain harbored the ctx gene. The presence of a zot gene in ctx- toxigenic V. mimicus indicates a possible role of ZOT in the toxigenicity of this species. We conclude that, in addition to ctx, V. mimicus and V. cholerae O139 have the potential to produce ZOT.

Near-Bottom Pelagic Bacteria at a Deep-Water Sewage Sludge Disposal Site

The epibenthic bacterial community at deep-ocean sewage sludge disposal site DWD-106, located approximately 106 miles (ca. 196 km) off the coast of New Jersey, was assessed for changes associated with the introduction of large amounts of sewage sludge. Mixed cultures and bacterial isolates obtained from water overlying sediment core samples collected at the deep-water (2,500 m) municipal sewage disposal site were tested for the ability to grow under in situ conditions of temperature and pressure. The responses of cultures collected at a DWD-106 station heavily impacted by sewage sludge were compared with those of samples collected from a station at the same depth which was not contaminated by sewage sludge. Significant differences were observed in the ability of mixed bacterial cultures and isolates from the two sites to grow under deep-sea pressure and temperature conditions. The levels of sludge contamination were established by enumerating Clostridium perfringens , a sewage indicator bacterium, in sediment samples from the two sites. The results of hybridization experiments in which DNAs extracted directly from the water overlying sediment core samples were used indicate that the reference site epibenthic community, the disposal site epibenthic community, and the community in a surface sludge plume share many members. Decreased culturability of reference site mixed cultures in the presence of sewage sludge was observed. Thus, the culturable portions of both the autochthonous and allochthonous bacterial communities at the disposal site may be inhibited in situ, the former by sewage sludge and the latter by high pressure and low temperature.

Benthic Distribution of Sewage Sludge Indicated by Clostridium perfringens at a Deep-Ocean Dump Site

Clostridium perfringens in sediment samples collected at the Deep Water Municipal Sewage Sludge Disposal Site (also called the 106-Mile Site), off the coast of New Jersey, was enumerated. The counts of C. perfringens found in sediment samples collected within and to the southwest of the 106-Mile Site were significantly elevated ( P < 0.01) compared with counts of samples from reference stations of similar depth (2,400 to 2,700 m), topography, and distance from the continental shelf, indicating that the benthic environment was contaminated by sewage dumping at this site. Low counts of C. perfringens in sediment samples collected at stations between the base of the continental shelf and the 106-Mile Site indicated that coastal runoff was not a significant source of contamination. Elevated counts were observed for samples up to 92 km to the southwest, whereas low counts were obtained for samples from stations to the east of the 106-Mile Site. This distribution is consistent with previous model predictions of sludge deposition. In areas heavily impacted by sludge dumping, C. perfringens counts were generally highest in the top 1 cm of sediment and exceeded 9,000 CFU g (dry weight) of sediment -1 . The patterns of C. perfringens dispersal observed in this study have proved useful for selection of heavily impacted areas and control stations for further ecological evaluation by a multidisciplinary research team.

Distribution of viruses in the Chesapeake Bay

High virus counts were found in water samples collected from the Chesapeake Bay. Viruses were enumerated by ultracentrifugation of water samples onto grids which were visualized by transmission electron microscopy. Virus counts in September 1990, April 1991, June 1991, August 1991, and October 1991 ranged between 2.6 x 10(6) and 1.4 x 10(8) viruses ml-1 with a mean of 2.5 x 10(7) viruses ml-1. Virus counts were usually at least three times higher than direct bacterial counts in corresponding samples. Virus counts in August and October were significantly higher than at the other sampling times, whereas bacterial counts were significantly lower at that time, yielding mean virus-to-bacterium ratios of 12.6 and 25.6, respectively. From analysis of morphology of the virus particles, it is concluded that a large proportion of the viruses are bacteriophages. The high virus counts obtained in this study suggest that viruses may be an important factor affecting bacterial populations in the Chesapeake Bay, with implications for gene transfer in natural aquatic bacterial populations and release of genetically engineered microorganisms to estuarine and coastal environments.

Molecular analysis of a novel glutamine synthetase of the anaerobe Bacteroides fragilis

The nucleotide sequence of a 2777 bp DNA segment containing the Bacteroides fragilis glnA gene was determined. The B. fragilis glnA open reading frame of 2187 bp encoded a glutamine synthetase (GS) subunit of 729 amino acid residues with a calculated Mr of 82,827. The apparent Mr of the GS subunit determined by SDS-PAGE was approximately 75,000. A single mRNA transcription start point was identified upstream of the B. fragilis glnA open reading frame. The B. fragilis GS subunit is approximately 270 and 400 amino acids longer than the GSI and GSII subunits, respectively, of other prokaryotes and eukaryotes. The GSI and GSII holoenzymes are dodecamers and octamers respectively, whereas the GS of B. fragilis is a hexamer. Although GSI and GSII subunits show amino acid similarity in five conserved regions, this similarity is not strongly conserved in the B. fragilis GS. The GS of B. fragilis is not regulated by adenylylation and lacks the adenylylation site. It also lacks the Trp residue associated with the active site in GSI and GSII enzymes from other prokaryotes and eukaryotes.

Development of pLR591, a Streptomyces-Escherichia coli positive selection shuttle vector

The Escherichia coli positive selection vector pEcoR251 was ligated with the broad host range, high copy number Streptomyces plasmid pIJ702 to produce pLR591, a Streptomyces-E. coli positive selection shuttle vector. The EcoRI and thiostrepton resistance genes of pLR591 were expressed in E. coli and Streptomyces lividans respectively. The positive selection shuttle vector pLR591 facilitates the construction in E. coli of genomic libraries which can be screened in Streptomyces strains.

Purification and characterisation of glutamine synthetase from Nocardia corallina

Glutamine synthetase (GS) (EC 6.3.1.2) has been purified 67-fold from Nocardia corallina. The apparent Mr of the GS subunit was approximately 56,000. Assuming the enzyme is a typical dodecamer this indicates a particle mass for the undissociated enzyme of 672,000. The GS is regulated by adenylylation and deadenylylation, and subject to feedback inhibition by alanine and glycine. The pH profiles assayed by the gamma-glutamyl transferase method were similar for NH+4-treated and untreated cell extracts and an isoactivity point was not obtained from these curves. GS activity was repressed by (NH4)2SO4 and glutamate. Cells grown in the presence of glutamine, alanine, proline and histidine had enhanced levels of GS activity. The GS of N. corallina cross-reacted with antisera prepared against GS from a Gram-negative Thiobacillus ferrooxidans strain but not with antisera raised against GS from a Gram-positive Clostridium acetobutylicum strain.

Syntheses, analgetic activity, and physical dependence capacity of 5-phenyl-6,7-benzomorphan derivatives

The synthesis, analgetic activity, and physical dependence capacity of a large number of 5-phenyl-6,7-benzomorphan derivatives are described. Observations made during the Stevens' rearrangement of 1-benzyl-1-methyl-delta 3-piperidinium salt derivatives (V) under various conditions are discussed. The absolute configuration of the 9-demethyl series and the 2'-deoxy series is established by comparison of their ORD and CD spectra with those of 49, whose absolute configuration was previously established by X-ray crystallography. A convenient synthesis of 3H-labeled phenols using 3H3PO4 is described, as well as the preparation of 14C-labeled compounds by conventional methods.