bluuebunny/crossref_metadata_2025 huggingface dataset:
Translation of Cryobiological Techniques to Socially Economically Deprived Populations—Part 2: Cryosurgery
Authors: Lugnani Franco , Zhao John Guojiang
Published: December 2019

Cold and cryogenic temperatures are used for treating cancer and other pathological conditions in various fields of medicine. Cryosurgery, which resides at the interface of medicine and engineering, has attracted the interest of engineers, scientists, and medical doctors. Recently, particularly since the end of the 1980s, technological developments in cryotherapy equipment and enormous advances in imaging techniques, such as computed tomography and ultrasonography, have allowed surgeons and interventional radiologists to precisely guide cryogenic probes into tumors while avoiding damage to surrounding tissues. Extensive studies have allowed us to conclude that the use of cryogenics facilitates the successful treatment of solid tumors in various organs such as lung, liver, bones, kidneys, prostate, etc. Its simplicity of use, effectiveness, low cost, and limited demand on hospital infrastructure and personnel have made cryosurgery particularly suitable for the treatment of patients of socio-economically deprived populations.
Synthetic baseline navigation using phase-coherent acoustic communication signals
Authors: Gallimore Eric , Anderson Mark , Freitag Lee , Terrill Eric
Published: December 2019

The development of a synthetic baseline navigation technique that self-localizes an autonomous underwater vehicle (AUV) using intermittent acoustic communications signals received by a single transducer is described, along with field results from in-ocean tests. The method uses the phase measurement at the output of a second-order phase-locked loop to create fine-scale pseudorange estimates in addition to, or in the absence of, a one-way travel time measurement based on the arrival time of the acoustic data packet. These range measurements are incorporated by an adaptive particle filter. This technique allows the vehicle navigation system to take advantage of multiple phase-derived range measurements made over the duration of a communication packet. These measurements, when incorporated with an appropriate filter and vehicle kinematic model, improve vehicle navigation at no additional cost in navigation-specific acoustic transmissions. This approach was demonstrated and evaluated with data collected at-sea using a REMUS 100 AUV (Hydroid, Inc., Pocasset, MA).
Automated localization of whales in coastal fjords
Authors: Hendricks Benjamin , Wray Janie L. , Keen Eric M. , Alidina Hussein M. , Gulliver T. Aaron , Picard Chris R.
Published: December 2019

Localization and tracking of vocalizing marine mammals are powerful tools for understanding and mitigating the impacts of anthropogenic stressors such as vessel noise on habitat use of cetaceans. A large-aperture hydrophone network has been installed in the Kitimat Fjord System, an ecologically, culturally, and economically valued marine environment in northern British Columbia, Canada. This network consists of four synchronized bottom-mounted hydrophones that permanently record and radio-transmit data to a land-based laboratory. An automated system has been developed which includes routines to localize transient bio-acoustic signals from three or more streaming hydrophones in near real-time. These routines comprise the correlation of hydrophone signals, the construction of a time lag model, and signal localization and error estimation from a spatial likelihood surface. The localization method was tested experimentally and subsequently applied to vocalizations from humpback whales, fin whales, and killer whales. Refractive and reflective sound propagation effects in the confined fjords are assessed using ray tracing propagation models. Automated localization results are compared to ground-truth data and shown to provide good accuracy.
Model-based Bayesian direction of arrival analysis for sound sources using a spherical microphone array
Authors: Landschoot Christopher R. , Xiang Ning
Published: December 2019

In many room acoustics and noise control applications, it is often challenging to determine the directions of arrival (DoAs) of incoming sound sources. This work seeks to solve this problem reliably by beamforming, or spatially filtering, incoming sound data with a spherical microphone array via a probabilistic method. When estimating the DoA, the signal under consideration may contain one or multiple concurrent sound sources originating from different directions. This leads to a two-tiered challenge of first identifying the correct number of sources, followed by determining the directional information of each source. To this end, a probabilistic method of model-based Bayesian analysis is leveraged. This entails generating analytic models of the experimental data, individually defined by a specific number of sound sources and their locations in physical space, and evaluating each model to fit the measured data. Through this process, the number of sources is first estimated, and then the DoA information of those sources is extracted from the model that is the most concise to fit the experimental data. This paper will present the analytic models, the Bayesian formulation, and preliminary results to demonstrate the potential usefulness of this model-based Bayesian analysis for complex noise environments with potentially multiple concurrent sources.
Bayesian coherent and incoherent matched-field localization and detection in the ocean
Authors: Michalopoulou Zoi-Heleni , Pole Andrew , Abdi Ali
Published: December 2019

Matched-field processing is applied to source localization and detection of sound sources in the ocean. The source spectrum is included in the set of unknown parameters and is estimated in the localization/detection process. Bayesian broadband (multi-tonal) incoherent and coherent processors are developed, integrating the source spectrum estimation using a Gibbs sampler and are first evaluated in source localization via point estimates and probability density functions obtained from synthetic signals. The coherent performance is superior to the incoherent one both in terms of source location estimates and density spread. The two processors are also applied to real data from the Hudson Canyon experiment. Subsequently, using Receiver Operating Characteristic (ROC) curves, the two processors are evaluated and compared in the task of joint detection and localization. The coherent detector/localization processor is superior to the incoherent one, especially as the number of frequencies increases. Joint detection and localization performance is evaluated with Localization-ROC curves.
Convolutional neural network for single-sensor acoustic localization of a transiting broadband source in very shallow water
Authors: Ferguson Eric L. , Williams Stefan B. , Jin Craig T.
Published: December 2019

When a broadband source of radiated noise transits past a fixed hydrophone, a Lloyd's mirror constructive/destructive interference pattern can be observed in the output spectrogram. By taking the spectrum of a (log) spectrum, the power cepstrum detects the periodic structure of the Lloyd's mirror fringe pattern by generating a sequence of pulses located at the fundamental quefrency and its multiples. The fundamental quefrency, which is the reciprocal of the frequency difference between adjacent destructive interference fringes, equates to the multipath delay time. An experiment is conducted where a motorboat transits past a hydrophone located about 1 m above the seafloor in very shallow water (20 m deep). The hydrophone has a frequency bandwidth of 90 kHz, and its output is sampled at 250 kHz. A cepstrogram database is compiled from multiple vessel transits, and its cepstrum-based feature vectors (along with ground-truth range data) form the input to train a convolutional neural network (CNN) so that it can predict the source range relative to the hydrophone for other (“unseen”) vessel transits. The CNN provides an accurate prediction of the instantaneous source range even when the range estimate from conventional multipath passive ranging is biased, which occurs at low grazing angles (<12°).
A deep neural network approach to acoustic source localization in a shallow water tank experiment
Authors: Yangzhou Jianyun , Ma Zhengyu , Huang Xun
Published: December 2019

In this paper, an acoustic source localization method using the emerging technology of the deep neural network (DNN) is proposed. After the construction and training of the DNN, the capability of the DNN for source localization through a set of numerical simulations is verified. Next, experimental studies and demonstrations in a very shallow water tank with acoustic reflective walls are prepared, which enable the quick acquisition of a huge amount of experimental data for the training of a one-dimensional DNN-based source localization model. The development of the DNN-based source localization method and the corresponding numerical and experimental demonstration constitute the main contribution of this work. The associated performance is then evaluated at various frequencies. In particular, the localization results of the DNN are compared with readily available model-based localization methods, such as the conventional matched field processing method and the normal-mode based multiple signal classification method. The comparison shows that the proposed DNN approach is able to produce satisfactory accuracy in this reflective shallow water tank environment, for which a forward acoustic propagating model is not required. Last but not least, the generality of the proposed DNN approach from one-dimensional localization to progressively more complicated two-dimensional tasks is also considered.
Time domain imaging of extended transient noise sources using phase coherence
Authors: Bilodeau Maxime , Quaegebeur Nicolas , Robin Olivier , O'Donoughue Patrick , Masson Patrice , Berry Alain
Published: December 2019

An acoustic imaging algorithm is proposed herein for transient noise source time reconstruction. Time domain formulations are not well suited for acoustic imaging because of the size of the resulting system to be inversed. Based on the phase coherence principle widely used in ultrasound imaging and image processing, the first step of the algorithm consists in proposing the phase coherence metric used to reject pixels that are unlikely to contribute to the radiated sound field. This translates in a reduction of the domain size and ill-posedness of the problem. In the second step, the inverse problem is solved using the Tikhonov regularization and the generalized cross-validation to extract the vibration field on the imaging domain. Two test cases are considered: a simulated baffled piston and a panel submitted to a mechanical impact in anechoic conditions. The actual vibration field of the panel is measured with an optical technique for reference. In both numerical and experimental cases, the reconstructed vibration field using the proposed approach compares well with their respective reference. The results confirm that transient excitations can be localized and quantified with the proposed approach, in contrast with the classical time-domain beamforming that dramatically overestimates its magnitude.
Long-range acoustic localization of artillery shots using distributed synchronous acoustic sensors
Authors: Dagallier Adrien , Cheinet Sylvain , Cosnefroy Matthias , Rickert Winfried , Weßling Thomas , Wey Pierre , Juvé Daniel
Published: December 2019

Acoustic recordings of artillery shots feature the signatures of the shot's muzzle, projectile, and impact waves modulated by the environment. This study aims at improving the sensing of such shots using a set of synchronous acoustic sensors distributed over a 1 km2 area. It uses the time matching approach, which is based on finding the best match between the observed and pre-calculated times of arrivals of the various waves at each sensor. The pre-calculations introduced here account for the complex acoustic source with a 6-degrees-of-freedom ballistic trajectory model, and for the propagation channel with a wavefront-tracking acoustic model including meteorological and terrain effects. The approach is demonstrated using three recordings of artillery shots measured by sensors which are more than 10 km from the point of fire and distributed at several hundred meters away from and around the target points. Using only the impact wave, it locates the impact point with an error of a few meters. Processing the muzzle and impact and projectile waves enables the estimation of the weapon's position with a 1 km error. Sensitivities of the localization method to various factors such as the number of sensors, atmospheric data, and the number of processed waves are discussed.
High-precision acoustic localization of dolphin sonar click transmissions using a modified method of passive ranging by wavefront curvature
Authors: Ferguson Eric L. , Ferguson Brian G.
Published: December 2019

When configured as a wide aperture array, only three hydrophones are required to localize dolphin sonar transmissions with unprecedented precision, even when the underwater sound scene of their natural habitat is complicated by many of them emitting echolocation “click” signals at the same time. Given the sensor position coordinates and speed of sound travel, the passive ranging by the wavefront curvature algorithm estimates the source range and bearing, using range difference measurements between signals, arriving at two adjacent pairs of widely spaced sensors. If the sensor positions are not strictly collinear, then the source range estimates are biased. This problem is overcome by modifying the input parameters to the basic passive ranging algorithm. The experimental results for the estimated source positions are found to agree with the predicted localization performance for a wide aperture array passive ranging sonar. The precision of the source bearing estimates is 0.005°, which is independent of the source range. The precision of the source range estimates degrades a hundredfold (from 2.5 cm to 2.6 m) for a tenfold increase in source range (33–318 m). A lower bound for the peak-to-peak source levels of Indo-Pacific bottlenose dolphins (Tursiops aduncus) is 183 ± 2 dB re 1 μPa for regular click pulses.
Introduction to the Special Issue on Acoustic Source Localization
Authors: Ferguson Brian , Gendron Paul J. , Michalopoulou Zoi-Heleni (Eliza) , Wong Kainam Thomas
Published: December 2019

Spatial localization based on acoustic observations is a rich field of interest in acoustic signal analysis. This special issue takes a close look at the diverse and growing range of problems in this area and the broad perspectives and methodologies that are presently being developed to solve them. The collection of articles presents recent advances in localization in complex and uncertain environments across a wide range of acoustic disciplines, from animal bioacoustics and acoustic signal processing in underwater environments to in air environments, architectural acoustics, and acoustic transduction.
Extracellular accumulation of a new amino acid, O-2-hydroxypropylhomoserine, from 1,2-propanediol by flavobacterium rigense
Authors: Yamada S , Nabe K , Ujimaru T , Izuo N , Chibata M
Published: December 2019

During an investigation of microorganisms utilizing petrochemicals, a strain identified as Flavobacterium rigense was found to accumulate a new amino acid in a medium containing 1,2-propanediol as the sole carbon source. Cultural conditions for the accumulation of the product were investigated, and as a result, the yield was increased to 2.8 mg/ml after a 5-day incubation in a medium containing 8% 1,2-propanediol. The pure amino acid was isolated, and its structure was investigated. Elemental analysis and infrared, nuclear magnetic resonance, and mass spectral analyses indicated that the amino acids is O-2-hydroxypropylhomoserine.
Automation of water bacteriological analysis: running test of an experimental prototype
Authors: Trinel P A , Hanoune N , Leclerc H
Published: December 2019

The experimental apparatus described enables continuous and automatic bacteriological water examination. It ensures the analysis and detection of Escherichia coli by incubation of the water samples and then detection of glutamic acid decarboxylase in coils according to the Technicon principles. The analysis is rapid: it is performed within 13 h with a sensitivity of better than 1 bacterium/100 ml, and 120 samples of 100 ml of water are examined in 24 h. Laboratory experiments and field testing showed that this prototype ensured a specific and sensitive analysis. They also provided information about the frequency of maintenance necessary to retain its efficiency. This device would allow, under the same conditions, the examination of liquid food products.
Combined effect of acetate and reduced water activity in survival of Salmonella typhimurium 7136
Authors: Meyer L B , Martin S E , Witter L D
Published: December 2019

Whereas Salmonella typhimurium 7136 will not grow at reduced water activity (aw), it was survival in such items as intermediate-moisture foods is of interest. Initial studies demonstrated that the addition of 0.3 M acetate (pH 4.7) to glycerol-Trypticase soy broth (BBL Microbiology Systems) solutions (aw 0.86) reduced the viability of S. typhimurium cells. The extent of death of cells exposed to reduced aw was increased by decreasing the pH or increasing the concentration of acetate. Acidification of glycerol-Trypticase soy broth reduced the D40 degrees C value exhibited by cells exposed to a range of aw solutions (0.65 to 0.92). Acetate appeared to affect survival more dramatically as aw values approached the minimum growth limit. Acidification with acetate also reduced cell survival in a variety of humectant solutions with an aw of 0.86 (glycerol, dextrose, and NaCl).
Isolation of Xanthomegnin from
Penicillium viridicatum
by Preparative High-Pressure Liquid Chromatography
Authors: Peterson R. E. , Grove M. D.
Published: December 2019

A method was developed for the production and purification of xanthomegnin from
Penicillium viridicatum
(NRRL 6430) cultured on rice at 15�C for 29 days. Liquid-liquid extraction followed by high-pressure liquid chromatography afforded 440 mg of crystalline xanthomegnin per kg of rice.
Immune response of Tilapia aurea exposed to Salmonella typhimurium
Authors: Baker D A , Smitherman R O
Published: December 2019

Tilapia aurea showed a specific immune response to Salmonella typhimurium. S. typhimurium was introduced into the gut of T. aurea by force-feeding. S. typhimurium was isolated from the fish viscera after 15 days, but at 30 days viable cells were not detected. T. aurea had an antibody titer to S. typhimurium after 30 days which was fivefold greater than the natural background antibody titer. An elevated antibody titer was not indicative of active bacterial infection.
Isolation and Characterization of a Halophilic Methanogen from Great Salt Lake
Authors: Paterek J. Robert , Smith Paul H.
Published: December 2019

A halophilic methanogenic microorganism isolated from sediments collected from the southern arm of Great Salt Lake, Utah, is described. Cells were irregular, nonmotile cocci approximately 1.0 μm in diameter and stained gram negative. Colonies from anaerobic plates and roll tubes were foamy, circular, and cream-yellow. Methanol, methylamine, dimethylamine, and trimethylamine supported growth and methanogenesis. Hydrogen-carbon dioxide, formate, and acetate were not utilized. Sodium and magnesium were required for growth; the optimum NaCl concentration ranged between 1.0 and 2.0 M, with the minimum doubling time occurring at 2.0 M. The optimum growth temperature was 35°C, with maximum growth rate occurring at pH 7.5. The DNA base composition was 48.5 mol% guanine + cytosine. SLP is the type strain designation (= ATCC 35705).

Images
Characteristics of methanogens isolated from bovine rumen
Authors: Miller T L , Wolin M J , Zhao H X , Bryant M P
Published: December 2019

Six strains of methanogens were isolated from 10(-8) and 10(-9) ml of bovine rumen contents. All strains had the morphologic and physiologic characteristics of Methanobrevibacter spp. Four strains required coenzyme M; two did not. Growth of all strains either depended on or was stimulated by a mixture of isobutyric, isovaleric, 2-methylbutyric, and valeric acids. None of the strains reacted with antiserum against the type strain of Methanobrevibacter ruminantium.
Evidence for plasmid-mediated toxin and bacteriocin production in Clostridium botulinum type G
Authors: Eklund M W , Poysky F T , Mseitif L M , Strom M S
Published: December 2019

A single 81-megadalton plasmid was previously isolated from each of six toxigenic strains of Clostridium botulinum type G (M. S. Strom, M. W. Eklund, and F. T. Poysky, Appl. Environ. Microbiol. 48:956-963, 1984). In this study, nontoxigenic derivatives isolated from each of the toxigenic strains following consecutive daily transfers in Trypticase (BBL Microbiology Systems, Cockeysville, Md.)-yeast extract-glucose broth at 44 degrees C simultaneously ceased to produce type G neurotoxin and to harbor the resident 81-megadalton plasmid. The nontoxigenic derivatives also ceased to produce bacteriocin and lost their immunity to the bacteriocin produced by the toxigenic strains. In contrast, all of the toxigenic isolates continued to carry the resident plasmid and to produce both bacteriocin and type G neurotoxin. This is the first evidence suggesting that the production of neurotoxin and bacteriocin by C. botulinum is mediated by a plasmid.
Lignin-solubilizing ability of actinomycetes isolated from termite (Termitidae) gut
Authors: Pasti M B , Pometto A L , Nuti M P , Crawford D L
Published: December 2019

The lignocellulose-degrading abilities of 11 novel actinomycete strains isolated from termite gut were determined and compared with that of the well-characterized actinomycete, Streptomyces viridosporus T7A. Lignocellulose bioconversion was followed by (i) monitoring the degradation of [14C]lignin- and [14C]cellulose-labeled phloem of Abies concolor to 14CO2 and 14C-labeled water-soluble products, (ii) determining lignocellulose, lignin, and carbohydrate losses resulting from growth on a lignocellulose substrate prepared from corn stalks (Zea mays), and (iii) quantifying production of a water-soluble lignin degradation intermediate (acid-precipitable polymeric lignin). The actinomycetes were all Streptomyces strains and could be placed into three groups, including a group of five strains that appear superior to S. viridosporus T7A in lignocellulose-degrading ability, three strains of approximately equal ability, and three strains of lesser ability. Strain A2 was clearly the superior and most effective lignocellulose decomposer of those tested. Of the assays used, total lignocellulose weight loss was most useful in determining overall bioconversion ability but not in identifying the best lignin-solubilizing strains. A screening procedure based on 14CO2 evolution from [14C-lignin]lignocellulose combined with measurement of acid-precipitable polymeric lignin yield was the most effective in identifying lignin-solubilizing strains. For the termite gut strains, the pH of the medium showed no increase after 3 weeks of growth on lignocellulose. This is markedly different from the pattern observed with S. viridosporus T7A, which raises the medium pH considerably. Production of extracellular peroxidases by the 11 strains and S. viridosporus T7A was followed for 5 days in liquid cultures.(ABSTRACT TRUNCATED AT 250 WORDS)
Identification of a Carboxylic Acid Metabolite from the Catabolism of Fluoranthene by a
Mycobacterium
sp
Authors: Kelley Ingrid , Freeman James P. , Evans Frederick E. , Cerniglia Carl E.
Published: December 2019

A
Mycobacterium
sp. previously isolated from oil-contaminated estuarine sediments was capable of extensively mineralizing the high-molecular-weight polycyclic aromatic hydrocarbon fluoranthene. A carboxylic acid metabolite accumulated and was isolated by thin-layer and high-pressure liquid chromatographic analyses of ethyl acetate extracts from acidified culture media. The metabolite reached a maximum concentration of approximately 0.65% after 24 h of incubation. On the basis of comparisons with authentic compound in which we used UV and fluorescence spectrophotometry and

R
f

values, as well as mass spectral and proton and carbon nuclear magnetic resonance spectral analyses, the metabolite was identified as 9-fluorenone-1-carboxylic acid. This is the first report in a microbial system of a fluoranthene metabolite in which significant degradation of one of the aromatic rings has occurred.
Polygalacturonase Production by
Agrobacterium tumefaciens
Biovar 3
Authors: McGuire Raymond G. , Rodriguez-Palenzuela Pablo , Collmer Alan , Burr Thomas J.
Published: December 2019

Agrobacterium tumefaciens
biovar 3 causes both crown gall and root decay of grape. Twenty-two
Agrobacterium
strains representing biovars 1, 2, and 3 were analyzed for tumorigenicity, presence of a Ti plasmid, ability to cause grape seedling root decay, and pectolytic activity. All of the biovar 3 strains, regardless of their tumorigenicity or presence of a Ti plasmid, caused root decay and were pectolytic, whereas none of the biovar 1 and 2 strains had these capacities. Isoelectrically focused gels that were activity stained with differentially buffered polygalacturonate-agarose overlays revealed that all of the biovar 3 strains produced a single polygalacturonase with a pH optimum of 4.5 and pIs ranging from 4.8 to 5.2. The enzyme was largely extracellular and was produced constitutively in basal medium supplemented with a variety of carbon sources including polygalacturonic acid. Lesions on grape seedling roots inoculated with
A. tumefaciens
biovar 3 strain CG49 yielded polygalacturonase activity with a pI similar to that of the enzyme produced by the bacterium in culture. These observations support the hypothesis that the polygalacturonase produced by
A. tumefaciens
biovar 3 has a role in grape root decay.
Chemotaxis of
Rhizobium meliloti
towards Nodulation Gene-Inducing Compounds from Alfalfa Roots
Authors: Dharmatilake Amitha J. , Bauer Wolfgang D.
Published: December 2019

Luteolin, a flavone present in seed exudates of alfalfa, induces nodulation genes (
nod
) in
Rhizobium meliloti
and also serves as a biochemically specific chemoattractant for the bacterium. The present work shows that
R. meliloti
RCR2011 is capable of very similar chemotactic responses towards 4′,7-dihydroxyflavone, 4′,7-Dihydroxyflavanone, and 4,4′-dihydroxy-2-methoxychalcone, the three principal
nod
gene inducers secreted by alfalfa roots. Chemotactic responses to the root-secreted
nod
inducers in capillary assays were usually two- to four-fold above background and, for the flavone and flavonone, occurred at concentrations lower than those required for half-maximal induction of the
nodABC
genes. Complementation experiments indicated that the lack of chemotactic responsiveness to luteolin seen in
nodD1
and
nodA
mutants of
R. meliloti
was not due to mutations in the
nod
genes, as previously thought. Thus, while
nod
gene induction and flavonoid chemotaxis have the same biochemical specificity, these two functions appear to have independent receptors or transduction pathways. The wild-type strain was found to suffer selective, spontaneous loss of chemotaxis towards flavonoids during laboratory subculture.
Characterization of the genome of the Rhodococcus rhodochrous bacteriophage NJL
Authors: Sunairi M , Watanabe T , Oda H , Murooka H , Nakajima M
Published: December 2019

Temperate bacteriophage NJL of Rhodococcus rhodochrous has a 49-kb linear double-stranded DNA with cohesive ends (cos). NJL DNA has unique target sites for HindIII and SspI, two target sites each for NheI and ScaI, and no cleavage site for AxyI, DraI, EcoRI, SacI, and SphI. The single-stranded regions of cos ends were ligated to each other with T4 DNA ligase, removed with mung bean nuclease, or blunted with the Klenow large fragment of DNA polymerase I; then the sequences of the cos ends were determined. Comparison of these sequences revealed that the single-stranded regions are complementary and 18 bases long and protrude at the 3' ends; they have the following sequences: 5'-TTGGCACCGTGGGAGGAG-3' and 3'-AACCGTGGCAC CCTCCTC-5'. A physical map of NJL was constructed by a cos mapping method based on information about the structure of the cohesive ends and multiple digestions with restriction endonucleases.
Isolation and Characterization of a
Pseudomonas
Strain Producing Glutaryl-7-Aminocephalosporanic Acid Acylase
Authors: Binder R. G. , Numata K. , Lowe D. A. , Murakami T. , Brown J. L.
Published: December 2019

Several screening methods were developed for the selection of
Pseudomonas
strains capable of hydrolyzing glutaryl-7-aminocephalosporanic acid to 7-aminocephalosporanic acid. An isolate exhibiting high acylase activity, designated BL072, was identified as a strain of
Pseudomonas diminuta
. It grew optimally at pH 7 to 8 and at a temperature of 32 to 40°C, but acylase activity was highest when the strain was grown at 28°C. Mutants of BL072 were generated by nitrosoguanidine treatment and screened for increased production of glutaryl-7-aminocephalosporanic acid acylase. A superior mutant gave a fourfold increase in acylase titer. The cell-associated acylase had similar activities against various glutaryl-cephems but had undetectable activity against cephalosporin C. This acylase may prove useful for the conversion of cephalosporin C to 7-aminocephalosporanic acid.
Plasmid Transfer into the Homoacetogen
Acetobacterium woodii
by Electroporation and Conjugation
Authors: Strätz Michael , Sauer Uwe , Kuhn Anita , Dürre Peter
Published: December 2019

Shuttle vectors (pMS3 and pMS4) which replicated in
Escherichia coli
and in gram-positive
Acetobacterium woodii
were constructed by ligating the replication origin of plasmid pAMβ1 with the
E. coli
cloning vector pUC19 and the
tetM
gene of streptococcal transposon Tn
916.
Electrotransformation of
A. woodii
was achieved at frequencies of 4.5 × 10
3
transformants per μg of plasmid DNA. For conjugal plasmid transfer, the mobilizable shuttle vector pKV12 was constructed by cloning the
tetM
gene into pAT187. Mating of
E. coli
containing pKV12 with
A. woodii
resulted in transfer frequencies of 3 × 10
-6
to 7 × 10
-6
per donor or recipient.
Group-specific 16S rRNA hybridization probes to describe natural communities of methanogens
Authors: Raskin L , Stromley J M , Rittmann B E , Stahl D A
Published: December 2019

Eight oligonucleotides which are complementary to conserved tracts of 16S rRNA from phylogenetically defined groups of methanogens were designed and characterized for use as hybridization probes for studies in environmental and determinative microbiology. The target-group specificity and temperature of dissociation for each probe were characterized. In general, the probes were very specific for the target methanogens and did not hybridize to the rRNAs of nontarget methanogens. Together, the eight probes circumscribe methanogens now represented in pure culture (with the exception of members of the family Methanothermaceae). Three probes are order specific; two identify members of the order Methanobacteriales, and one is specific for the order Methanococcales. The fourth probe encompasses three families belonging to the order Methanomicrobiales, the third order within the current classification. The fifth probe is specific for the remaining family within this order (Methanosarcinaceae). Three additional probes encompass different genera within the Methanosarcinaceae.
Colloidal and Dissolved Organic Matter Excreted by a Mixotrophic Flagellate during Bacterivory and Autotrophy
Authors: Tranvik Lars
Published: December 2019

Excretion of dissolved and colloidal organic carbon by a mixotrophic flagellate, the chrysophyte
Poterioochromonas malhamensis,
was studied. Flagellates were incubated either with
14
C-labeled bacteria or with inorganic
14
C, in order to compare organic exudates originating from primary production with exudates originating from ingested bacteria. Colloids of >0.02 μm constituted a larger fraction of the exudates originating from ingested bacteria, compared with exudates derived from primary production. Flagellate feeding on bacteria specifically labeled in different cell components was compared. Cell wall components gave rise to less colloidal organic carbon than did other cell constituents. To investigate the degradability of flagellate
14
C-exudates, they were added to lake water and mineralization to
14
CO
2
was monitored. Bacterially derived exudates were more recalcitrant than exudates originating from photosynthesis. The results support the hypothesis that bacterial utilization of labile organic compounds, followed by flagellate bacterivory and exudation, results in a transformation of labile organic matter into more recalcitrant forms.
Immune Function in Healthy Adolescents
Authors: Bartlett Jacqueline A. , Schleifer Steven J. , Demetrikopoulos Melissa K. , Delaney Beverly R. , Shiflett Samuel C. , Keller Steven E.
Published: December 2019

In the present study, we examine immunological functioning in normal healthy African-American and Latino/Latina adolescents recruited from an inner-city high school and an inner-city clinic. A battery of tests was performed with enumerative and functional measures which encompassed both innate and adaptive immunity. We found immune differences related to age, gender, and race on both the enumerative and the functional immune measures. This data expands the available body of information concerning normal immunity in healthy adolescents.
Evaluation of a Commercial Capture Enzyme-Linked Immunosorbent Assay for Detection of Immunoglobulin M and G Antibodies Produced during Dengue Infection
Authors: Sang Chew Theng , Cuzzubbo Andrea J. , Devine Peter L.
Published: December 2019

A commercially available capture enzyme-linked immunosorbent assay (ELISA) for the detection of specific immunoglobulin M (IgM) and IgG antibodies produced during dengue infection (PanBio Dengue Duo) was evaluated with paired serum specimens from 176 patients. Diagnosis was based on a hemagglutination inhibition (HAI) assay, with patients having either primary dengue (
n
= 90), secondary dengue (
n
= 58), or no dengue (
n
= 28) infection. The combined use of IgM and IgG (sensitivity, 99%; specificity, 96%) was superior to the use of IgM alone (sensitivity, 88%; specificity, 96%) or IgG alone (sensitivity, 85%; specificity, 96%). Furthermore, with the first serum sample of the pair of serum samples, the ELISA was able to diagnose significantly more cases of dengue than the HAI assay (55% versus 14%). The results of the IgG capture ELISA gave a significant correlation with those of the HAI assay (
r
= 0.91;
P
< 0.0001), and the IgG capture ELISA could be used to distinguish between primary and secondary infection. The best distinction was observed when an IgG cutoff ratio of 3.0 was used, with 88% of primary infections and 98% of secondary infections being correctly classified. This ELISA should prove to be useful in the clinical diagnosis of dengue infection.
Detection of Antibodies to Human Immunodeficiency Virus Type 1 in Oral Fluids: A Large-Scale Evaluation of Immunoassay Performance
Authors: Granade Timothy C. , Phillips Susan K. , Parekh Bharat , Gomez Perry , Kitson-Piggott Wendy , Oleander Herbert , Mahabir Bisram , Charles Waveney , Lee-Thomas Stephanie
Published: December 2019

Paired serum and oral-fluid (OF) specimens (
n
= 4,448) were collected from blood donors and patients attending local sexually transmitted disease clinics in Trinidad and Tobago and the Bahamas and were tested for the presence of human immunodeficiency virus type 1 (HIV-1) antibodies. Sera were tested by Abbott AB HIV-1/HIV-2 (rDNA) enzyme immunoassay (EIA), and positive specimens were confirmed by Cambridge HIV-1 and HIV-2 Western blotting (WB). OF specimens were collected with the OraSure collection device and were tested by Murex GACELISA and by two EIAs from Organon Teknika (the Oral Fluid Vironostika HIV-1 Microelisa System [OTC-L] and the Vironostika HIV-1 Microelisa System [OTC-M]). EIA-reactive OF specimens were confirmed by miniaturized WB (OFWB). GACELISA detected all 474 HIV-1 seropositive specimens (sensitivity, 100%). OTC-L detected 470 positive specimens (sensitivity, 99.2%), while OTC-M detected 468 positive specimens (sensitivity, 98.8%). Specificities ranged from 99.2 to 100% for the three assays. Concordance of OFWB with serum WB was 99.4%, and banding patterns determined by the two methods were similar. The immunoglobulin G (IgG) concentration of OF specimens ranged from 0.21 to 100 μg/ml, with a mean of 17.1 μg/ml. Significant differences in OF IgG concentrations were observed between HIV antibody-positive and HIV antibody-negative persons (31.94 versus 15.28 μg/ml, respectively [
P
< 0.0001]). These data further confirm the suitability of OF specimens for detection of HIV-1 antibodies. Currently available HIV-1 antibody assays provide sensitivities and specificities with OF specimens comparable to those achieved with serum specimens.
Capsular Serotype and Antibiotic Resistance of
Streptococcus pneumoniae
Isolates in Two Chilean Cities
Authors: Inostroza Jaime , Trucco Olivia , Prado Valeria , Vinet Ana Maria , Retamal Gloria , Ossa Gonzalo , Facklam Richard R. , Sorensen Ricardo U.
Published: December 2019

We compared the incidence of nasopharyngeal colonization by
Streptococcus pneumoniae
, the serotypes causing mucosal and invasive diseases, and the antibiotic resistance of these strains in patients admitted to three large hospitals and children attending day care centers in two Chilean cities (Santiago and Temuco). The populations in both cities were similar in ethnic background, socioeconomic status, family size, and access to medical care. Significant differences in nasopharyngeal colonization rates, in serotypes causing infections, and in antibiotic resistance were found between the two cities. In children 0 to 2 years of age, 42% were colonized with
S. pneumoniae
in Santiago compared to 14% in Temuco. A total of 41 serotypes were identified in both Chilean cities studied. Six serotypes were found only in Santiago; 14 serotypes were found only in Temuco. Antibiotic-resistant serotypes 6A, 6B, 14, 19F, and 23F were detected only in Santiago. We show that important differences in the incidence of nasopharyngeal carriage, infection, and
S. pneumoniae
serotypes can exist in similar populations in different areas of the same country. Our findings are relevant for prevention strategies, antibiotic usage, and vaccine design.
Evaluation of Previously Assigned Antibody Concentrations in Pneumococcal Polysaccharide Reference Serum 89SF by the Method of Cross-Standardization
Authors: Concepcion Nelydia , Frasch Carl E.
Published: December 2019

An enzyme-linked immunosorbent assay (ELISA) and the antibody concentrations assigned to different pneumococcal capsular polysaccharide types were used to estimate concentrations of antibody to additional pneumococcal types in reference serum 89SF and to confirm assigned antibody values. This was possible because the slopes of curves of antibody binding to all polysaccharide types evaluated (1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F) were similar. The point estimates for total anti-pneumococcal antibody and immunoglobulin G (IgG) antibody determined by cross-standardization by an ELISA based on use of methylated human serum albumin (mHSA) to improve the efficiency of polysaccharide binding to the ELISA plate differed by less than 40% from those reported by Quataert et al. (Clin. Diagn. Lab. Immunol. 2:590–597, 1995) for types 1, 4, 6B, 7F, 9V, 14, 18C, and 23F. However, large differences were found between the assigned values and those obtained by our mHSA ELISA for types 3 and 19F. The mHSA ELISA and the direct polysaccharide coat ELISA may not measure antibodies to the same epitopes on polysaccharides of types 3 and 19F. The functional importance of these different antibody specificities is being investigated. We have thus confirmed the assigned IgG antibody values for most types by a different method and have extended antibody assignments to several additional types.
Dehydroepiandrosterone Sulfate Treatment of Mice Modulates Infection with
Schistosoma mansoni
Authors: Fallon Padraic G. , Richardson Emma J. , Jones Frances M. , Dunne David W.
Published: December 2019

Female mice treated with dehydroepiandrosterone sulfate early during infection were partially protected (
P
< 0.05–0.005) from
Schistosoma mansoni
infection. Hormone treatment did not modify parasite-specific cellular or humoral responses. Serum dehydroepiandrosterone sulfate levels and testosterone infection were negatively correlated,
r
= −0.621 and
r
= −0.653, respectively, with schistosome worm burden. The partial resistance to schistosome infection in dehydroepiandrosterone sulfate-treated female mice may be due to the known antischistosomular activity of testosterone.
Absolute CD4 Counts Obtained by a Three-Color Flow-Cytometric Method without the Use of a Hematology Analyzer
Authors: Alexander Thomas S.
Published: December 2019

We evaluated the Ortho TRIO-Cytoronabsolute system for determining absolute CD4 counts. The CD4 counts in our blood specimens from 100 individuals ranged from 3 to 1,962; the percent CD4 ranged from 1.3 to 62.2, respectively. The TRIO system was biased toward lower absolute counts than a combination of flow cytometry and hematology but showed no bias in percent CD4 calculations.
Differentiation of F18ab+from F18ac+Escherichia coliby Single-Strand Conformational Polymorphism Analysis of the Major Fimbrial Subunit Gene (fedA)
Authors: Bosworth Brad T. , Dean-Nystrom Evelyn A. , Casey Thomas A. , Neibergs Holly L.
Published: December 2019

Toxin-producingEscherichia coliexpressing F18 fimbriae colonizes the small intestines of weaned pigs and causes diarrhea, edema disease, or both. The F18 family is composed of two antigenic variants, F18ab and F18ac. Because many strains do not express F18 fimbriae in vitro, identification and differentiation of these two variants are difficult. Single-strand conformational polymorphism (SSCP) analysis is a rapid method for identifying genetic mutations and polymorphisms. The F18 major fimbrial subunit genes (fedA) of 138 strains were amplified by PCR, and genetic differences were detected by SSCP analysis. The SSCP analysis of thefedAgene differentiated F18ab+strains from F18ac+strains. Most strains classified as F18ab+by SSCP analysis contained Shiga toxin 2e and enterotoxin genes. Most strains classified as F18ac+by SSCP analysis contained only enterotoxin genes. The SSCP analysis was a useful method for predicting the antigenicity of F18+E. coliand could also be used for analysis of other virulence genes inE. coliand other pathogenic bacteria.
In Vitro p24 Antigen-Stimulated Lymphocyte Proliferation and β-Chemokine Production in Human Immunodeficiency Virus Type 1 (HIV-1)-Seropositive Subjects after Immunization with an Inactivated gp120-Depleted HIV-1 Immunogen (Remune)
Authors: Moss Ronald B. , Wallace Mark R. , Lanza Paola , Giermakowska Wieslawa , Jensen Fred C. , Theofan Georgia , Chamberlin Carolyn , Richieri Steven P. , Carlo Dennis J.
Published: December 2019

We examined the effect of immune stimulation by a human immunodeficiency virus type 1 (HIV-1) immunogen (Remune) compared to a non-HIV vaccine (influenza) on HIV-1-specific immune responses in HIV-1-seropositive subjects. HIV-1 p24 antigen-stimulated lymphocyte proliferation was not augmented after immunization with the influenza vaccine. In contrast, subjects increased their lymphocyte proliferative responses to p24 antigen after one immunization with HIV-1 immunogen (Remune) (gp120-depleted inactivated HIV-1 in incomplete Freund’s adjuvant). Furthermore, p24 antigen-stimulated β-chemokine production (RANTES, MIP-1α, MIP-1β) was also augmented after immunization with the HIV-1 immunogen but not influenza vaccine. Taken together, these results suggest that in this cohort, HIV-specific immune responses to p24 antigen can be augmented after immunization with an HIV-1 immunogen. The ability to upregulate immune responses to the more conserved core proteins may have important implications in the development of immunotherapeutic interventions for HIV-1 infection.
Increased Prevalence of Immunoglobulin A Deficiency in Patients with the Chromosome 22q11.2 Deletion Syndrome (DiGeorge Syndrome/Velocardiofacial Syndrome)
Authors: Smith Christopher A. , Driscoll Deborah A. , Emanuel Beverly S. , McDonald-McGinn Donna M. , Zackai Elaine H. , Sullivan Kathleen E.
Published: December 2019

We wished to determine the prevalence of immunoglobulin A (IgA) deficiency in patients with the chromosome 22q11.2 deletion syndrome. A total of 32 patients with the chromosome 22q11.2 deletion were examined for IgA deficiency. We report a 13% (
n
= 4) prevalence of IgA deficiency in patients with this syndrome. The odds ratio of IgA deficiency in this population is 14.20 (
P
< 0.0001). This confirms the occurrence of significant humoral deficits in this predominantly cellular immunodeficiency.
Diagnostic Value of Proteins of ThreeBorreliaSpecies (Borrelia burgdorferiSensu Lato) and Implications for Development and Use of Recombinant Antigens for Serodiagnosis of Lyme Borreliosis in Europe
Authors: Hauser Ulrike , Lehnert Gisela , Wilske Bettina
Published: December 2019

More and more assays for the serodiagnosis of Lyme borreliosis (LB) are based on recombinant antigens. However, so far, there is no consensus as to which are the most specific and sensitive proteins and how they should be used in combination to obtain tests with the best discrimination abilities. The present study was preceded by a detailed analysis of Western blots (WB) using whole-cell lysates ofBorrelia burgdorferisensu stricto strain PKa2,B. afzeliiPKo, andB. gariniiPBi (U. Hauser, G. Lehnert, R. Lobentanzer, and B. Wilske, J. Clin. Microbiol. 35:1433–1444, 1997). For the present work, the data bank from that study, containing information about the reactivities of 330 sera (from patients at different stages of LB [n= 189]; control group,n= 141), was reused. The specificities and sensitivities of various combinations of proteins from different strains were calculated for different interpretation criteria. For immunoglobulin G (IgG) WB, the recommended combination of antigens available to date as recombinant proteins included p83/100 of PKa2, p83/100 of PKo, p39 of PKo, p39 of PBi, and OspC of PBi (interpretation criterion, at least one reactive band required for a positive WB; specificity, 96.5%; sensitivity, 56.1%). The further addition of p58 of PKo, p17 of PKo, or p14 of PKo was most favorable in terms of both a considerable gain of sensitivity and little loss of specificity. IgG Western blotting with a whole-cell lysate of strain PKo might be improved by the addition of OspC of PBi. For IgG WB, the best combination, out of all bands, was p83/100, p58, p39, p30, and p21 of all three strains and OspC of PBi, p17b of PBi, p56 of PKa2, p43 of PKo, p17 of PKo, and p14 of PKo (interpretation criterion, at least two reactive bands required for a positive WB; specificity, 97.2%; sensitivity, 61.4%). An interpretation criterion of at least two reactive bands is more reliable than one of only one reactive band. For IgM WB, the best combination was OspC of PKo, OspC of PBi, p39 of all three strains, p17 of PKo, and strong reactions with p41 of all three strains (interpretation criterion, at least one reactive band required; specificity, 97.9%; sensitivity, 47.0%).