bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Mineral Flotation Process Using
Thiobacillus ferrooxidans
Authors: Nagaoka Toru , Ohmura Naoya , Saiki Hiroshi 
Published: December 2019

ABSTRACT

Oxidative leaching of metals by
Thiobacillus ferrooxidans
has proven useful in mineral processing. Here, we report on a new use for
T. ferrooxidans
, in which bacterial adhesion is used to remove pyrite from mixtures of sulfide minerals during flotation. Under control conditions, the floatabilities of five sulfide minerals tested (pyrite, chalcocite, molybdenite, millerite, and galena) ranged from 90 to 99%. Upon addition of
T. ferrooxidans
, the floatability of pyrite was significantly suppressed to less than 20%. In contrast, addition of the bacterium had little effect on the floatabilities of the other minerals, even when they were present in relatively large quantities: their floatabilities remained in the range of 81 to 98%.
T. ferrooxidans
thus appears to selectively suppress pyrite floatability. As a consequence, 77 to 95% of pyrite was removed from mineral mixtures while 72 to 100% of nonpyrite sulfide minerals was recovered. The suppression of pyrite floatability was caused by bacterial adhesion to pyrite surfaces. When normalized to the mineral surface area, the number of cells adhering to pyrite was significantly larger than the number adhering to other minerals. These results suggest that flotation with
T. ferrooxidans
may provide a novel approach to mineral processing in which the biological functions involved in cell adhesion play a key role in the separation of minerals.
Sunlight Inactivation of Fecal Bacteriophages and Bacteria in Sewage-Polluted Seawater
Authors: Sinton Lester W. , Finlay Rochelle K. , Lynch Philippa A. 
Published: December 2019

ABSTRACT

Sunlight inactivation rates of somatic coliphages, F-specific RNA bacteriophages (F-RNA phages), and fecal coliforms were compared in seven summer and three winter survival experiments. Experiments were conducted outdoors, using 300-liter 2% (vol/vol) sewage-seawater mixtures held in open-top chambers. Dark inactivation rates (

k
D

s), measured from exponential survival curves in enclosed (control) chambers, were higher in summer (temperature range: 14 to 20°C) than in winter (temperature range: 8 to 10°C). Winter

k
D

s were highest for fecal coliforms and lowest for F-RNA phages but were the same or similar for all three indicators in summer. Sunlight inactivation rates (

k
S

), as a function of cumulative global solar radiation (insolation), were all higher than the

k
D

s with a consistent

k
S

ranking (from greatest to least) as follows: fecal coliforms, F-RNA phages, and somatic coliphages. Phage inactivation was exponential, but bacterial curves typically exhibited a shoulder. Phages from raw sewage exhibited

k
S

s similar to those from waste stabilization pond effluent, but raw sewage fecal coliforms were inactivated faster than pond effluent fecal coliforms. In an experiment which included F-DNA phages and
Bacteroides fragilis
phages, the

k
S

ranking (from greatest to least) was as follows: fecal coliforms, F-RNA phages,
B. fragilis
phages, F-DNA phages, and somatic coliphages. In a 2-day experiment which included enterococci, the initial concentration ranking (from greatest to least: fecal coliforms, enterococci, F-RNA phages, and somatic coliphages) was reversed during sunlight exposure, with only the phages remaining detectable by the end of day 2. Inactivation rates under different optical filters decreased with the increase in spectral cutoff wavelength (50% light transmission) and indicated that F-RNA phages and fecal coliforms are more susceptible than somatic coliphages to longer solar wavelengths, which predominate in seawater. The consistently superior survival of somatic coliphages in our experiments suggests that they warrant further consideration as fecal, and possibly viral, indicators in marine waters.
Seasonal Variations in Microbial Populations and Environmental Conditions in an Extreme Acid Mine Drainage Environment
Authors: Edwards Katrina J. , Gihring Thomas M. , Banfield Jillian F. 
Published: December 2019

ABSTRACT

Microbial populations, their distributions, and their aquatic environments were studied over a year (1997) at an acid mine drainage (AMD) site at Iron Mountain, Calif. Populations were quantified by fluorescence in situ hybridizations with group-specific probes. Probes were used for the domains
Eucarya
,
Bacteria
, and
Archaea
and the two species most widely studied and implicated for their role in AMD production,
Thiobacillus ferrooxidans
and
Leptospirillum ferrooxidans
. Results show that microbial populations, in relative proportions and absolute numbers, vary spatially and seasonally and correlate with geochemical and physical conditions (pH, temperature, conductivity, and rainfall). Bacterial populations were in the highest proportion (>95%) in January. Conversely, archaeal populations were in the highest proportion in July and September (∼50%) and were virtually absent in the winter. Bacterial and archaeal populations correlated with conductivity and rainfall. High concentrations of dissolved solids, as reflected by high conductivity values (up to 125 mS/cm), occurred in the summer and correlated with high archaeal populations and proportionally lower bacterial populations. Eukaryotes were not detected in January, when total microbial cell numbers were lowest (<10
5
cells/ml), but eukaryotes increased at low-pH sites (∼0.5) during the remainder of the year. This correlated with decreasing water temperatures (50 to 30°C; January to November) and increasing numbers of prokaryotes (10
8
to 10
9
cells/ml).
T. ferrooxidans
was in highest abundance (>30%) at moderate pHs and temperatures (∼2.5 and 20°C) in sites that were peripheral to primary acid-generating sites and lowest (0 to 5%) at low-pH sites (pH ∼0.5) that were in contact with the ore body.
L. ferrooxidans
was more widely distributed with respect to geochemical conditions (pH = 0 to 3; 20 to 50°C) but was more abundant at higher temperatures and lower pHs (∼40°C; pH ∼0.5) than
T. ferrooxidans
.
Microbial Reduction of Fe(III) in Acidic Sediments: Isolation of
Acidiphilium cryptum
JF-5 Capable of Coupling the Reduction of Fe(III) to the Oxidation of Glucose
Authors: Küsel Kirsten , Dorsch Tanja , Acker Georg , Stackebrandt Erko 
Published: December 2019

ABSTRACT

To evaluate the microbial populations involved in the reduction of Fe(III) in an acidic, iron-rich sediment, the anaerobic flow of supplemental carbon and reductant was evaluated in sediment microcosms at the in situ temperature of 12°C. Supplemental glucose and cellobiose stimulated the formation of Fe(II); 42 and 21% of the reducing equivalents that were theoretically obtained from glucose and cellobiose, respectively, were recovered in Fe(II). Likewise, supplemental H
2
was consumed by acidic sediments and yielded additional amounts of Fe(II) in a ratio of approximately 1:2. In contrast, supplemental lactate did not stimulate the formation of Fe(II). Supplemental acetate was not consumed and inhibited the formation of Fe(II). Most-probable-number estimates demonstrated that glucose-utilizing acidophilic Fe(III)-reducing bacteria approximated to 1% of the total direct counts of 4′,6-diamidino-2-phenylindole-stained bacteria. From the highest growth-positive dilution of the most-probable-number series at pH 2.3 supplemented with glucose, an isolate, JF-5, that could dissimilate Fe(III) was obtained. JF-5 was an acidophilic, gram-negative, facultative anaerobe that completely oxidized the following substrates via the dissimilation of Fe(III): glucose, fructose, xylose, ethanol, glycerol, malate, glutamate, fumarate, citrate, succinate, and H
2
. Growth and the reduction of Fe(III) did not occur in the presence of acetate. Cells of JF-5 grown under Fe(III)-reducing conditions formed blebs, i.e., protrusions that were still in contact with the cytoplasmic membrane. Analysis of the 16S rRNA gene sequence of JF-5 demonstrated that it was closely related to an Australian isolate of
Acidiphilium cryptum
(99.6% sequence similarity), an organism not previously shown to couple the complete oxidation of sugars to the reduction of Fe(III). These collective results indicate that the in situ reduction of Fe(III) in acidic sediments can be mediated by heterotrophic
Acidiphilium
species that are capable of coupling the reduction of Fe(III) to the complete oxidation of a large variety of substrates including glucose and H
2
.
Multiplex PCR Screening To Detectcry9Genes inBacillus thuringiensisStrains
Authors: Ben-Dov Eitan , Wang Qingfeng , Zaritsky Arieh , Manasherob Robert , Barak Ze’ev , Schneider Bert , Khamraev Aloviddin , Baizhanov Mukhtar , Glupov Victor , Margalith Yoel 
Published: December 2019

ABSTRACTAn extended PCR method was established to rapidly identify and classifyBacillus thuringiensisstrains containingcry(crystal protein) genes toxic to lepidopteran, coleopteran, and dipteran pests (Ben-Dov et al., Appl. Environ. Microbiol. 63:4883–4890, 1997). To optimize identification of all reportedcrygenes, this methodology needs a complete PCR set of primers. In the study reported here, a set of universal (Un9) and specific primers for multiplex rapid screening for all four known genes from thecry9group was designed. PCR analyses were performed forcry9genes on 16 standard strains and 215 field isolates ofB. thuringiensis. Among the standard strains, onlyB. thuringiensissubsp.aizawaiHD-133, which harborscry1andcry2genes, was positive with Un9 but negative to all four specific primers forcry9genes. DNA of 22 field-collected isolates was also found to be positive with Un9. These isolates were classified into threecry9profiles using specific primers; all of them harborcry1andcry2. This newly designed set of primers complements the existing PCR methodology for most currently knowncrygenes.
Biocontrol of
Escherichia coli
O157 with O157-Specific Bacteriophages
Authors: Kudva Indira T. , Jelacic Srdjan , Tarr Phillip I. , Youderian Philip , Hovde Carolyn J. 
Published: December 2019

ABSTRACT

Escherichia coli
O157 antigen-specific bacteriophages were isolated and tested to determine their ability to lyse laboratory cultures of
Escherichia coli
O157:H7. A total of 53 bovine or ovine fecal samples were enriched for phage, and 5 of these samples were found to contain lytic phages that grow on
E. coli
O157:H7. Three bacteriophages, designated KH1, KH4, and KH5, were evaluated. At 37 or 4°C, a mixture of these three O157-specific phages lysed all of the
E. coli
O157 cultures tested and none of the non-O157
E. coli
or non-
E. coli
cultures tested. These results required culture aeration and a high multiplicity of infection. Without aeration, complete lysis of the bacterial cells occurred only after 5 days of incubation and only at 4°C. Phage infection and plaque formation were influenced by the nature of the host cell O157 lipopolysaccharide (LPS). Strains that did not express the O157 antigen or expressed a truncated LPS were not susceptible to plaque formation or lysis by phage. In addition, strains that expressed abundant mid-range-molecular-weight LPS did not support plaque formation but were lysed in liquid culture. Virulent O157 antigen-specific phages could play a role in biocontrol of
E. coli
O157:H7 in animals and fresh foods without compromising the viability of other normal flora or food quality.
An Effective Strategy, Applicable to
Streptococcus salivarius
and Related Bacteria, To Enhance or Confer Electroporation Competence
Authors: Buckley Nicole D. , Vadeboncoeur Christian , LeBlanc Donald J. , Lee Linda N. , Frenette Michel 
Published: December 2019

ABSTRACT

Despite the large number of techniques available for transformation of bacteria, certain species and strains are still resistant to introduction of foreign DNA. Some oral streptococci are among the organisms that can be particularly difficult to transform. We performed a series of experiments that involved manipulation of growth and recovery media and cell wall weakening, in which the electroporation conditions, cell concentration, and type and concentration of the transforming plasmid were varied. The variables were optimized such that a previously untransformable
Streptococcus salivarius
strain, ATCC 25975, could be transformed reproducibly at a level of 10
5
transformants per μg of DNA. The technique was used to introduce a plasmid into other strains of
S. salivarius
, including a fresh isolate. Moreover, the same technique was applied successfully to a wide range of oral streptococci and other gram-positive bacteria.
Marine Bacterial Isolates Display Diverse Responses to UV-B Radiation
Authors: Joux Fabien , Jeffrey Wade H. , Lebaron Philippe , Mitchell David L. 
Published: December 2019

ABSTRACT

The molecular and biological consequences of UV-B radiation were investigated by studying five species of marine bacteria and one enteric bacterium. Laboratory cultures were exposed to an artificial UV-B source and subjected to various post-UV irradiation treatments. Significant differences in survival subsequent to UV-B radiation were observed among the isolates, as measured by culturable counts. UV-B-induced DNA photodamage was investigated by using a highly specific radioimmunoassay to measure cyclobutane pyrimidine dimers (CPDs). The CPDs determined following UV-B exposure were comparable for all of the organisms except
Sphingomonas
sp. strain RB2256, a facultatively oligotrophic ultramicrobacterium. This organism exhibited little DNA damage and a high level of UV-B resistance. Physiological conditioning by growth phase and starvation did not change the UV-B sensitivity of marine bacteria. The rates of photoreactivation following exposure to UV-B were investigated by using different light sources (UV-A and cool white light). The rates of photoreactivation were greatest during UV-A exposure, although diverse responses were observed. The differences in sensitivity to UV-B radiation between strains were reduced after photoreactivation. The survival and CPD data obtained for
Vibrio natriegens
when we used two UV-B exposure periods interrupted by a repair period (photoreactivation plus dark repair) suggested that photoadaptation could occur. Our results revealed that there are wide variations in marine bacteria in their responses to UV radiation and subsequent repair strategies, suggesting that UV-B radiation may affect the microbial community structure in surface water.
Degradation of 4-Fluorobiphenyl by Mycorrhizal Fungi as Determined by
19
F Nuclear Magnetic Resonance Spectroscopy and
14
C Radiolabelling Analysis
Authors: Green N. A. , Meharg A. A. , Till C. , Troke J. , Nicholson J. K. 
Published: December 2019

ABSTRACT

The pathways of biotransformation of 4-fluorobiphenyl (4FBP) by the ectomycorrhizal fungus
Tylospora fibrilosa
and several other mycorrhizal fungi were investigated by using
19
F nuclear magnetic resonance (NMR) spectroscopy in combination with
14
C radioisotope-detected high-performance liquid chromatography (
14
C-HPLC). Under the conditions used in this study
T. fibrillosa
and some other species degraded 4FBP.
14
C-HPLC profiles indicated that there were four major biotransformation products, whereas
19
F NMR showed that there were six major fluorine-containing products. We confirmed that 4-fluorobiphen-4′-ol and 4-fluorobiphen-3′-ol were two of the major products formed, but no other products were conclusively identified. There was no evidence for the expected biotransformation pathway (namely,
meta
cleavage of the less halogenated ring), as none of the expected products of this route were found. To the best of our knowledge, this is the first report describing intermediates formed during mycorrhizal degradation of halogenated biphenyls.
Detection of Viral Pathogens by Reverse Transcriptase PCR and of Microbial Indicators by Standard Methods in the Canals of the Florida Keys
Authors: Griffin Dale W. , Gibson Charles J. , Lipp Erin K. , Riley Kelley , Paul John H. , Rose Joan B. 
Published: December 2019

ABSTRACT

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms,
Escherichia coli
,
Clostridium perfringens
, enterococci, coliphages, F-specific (F
+
) RNA coliphages,
Giardia lamblia
,
Cryptosporidium parvum
, and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1,410,
E. coli
organisms from <1 to 130,
Clostridium
spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F
+
phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.
Community Size and Metabolic Rates of Psychrophilic Sulfate-Reducing Bacteria in Arctic Marine Sediments
Authors: Knoblauch Christian , Jørgensen Bo Barker , Harder Jens 
Published: December 2019

ABSTRACT
The numbers of sulfate reducers in two Arctic sediments with in situ temperatures of 2.6 and −1.7°C were determined. Most-probable-number counts were higher at 10°C than at 20°C, indicating the predominance of a psychrophilic community. Mean specific sulfate reduction rates of 19 isolated psychrophiles were compared to corresponding rates of 9 marine, mesophilic sulfate-reducing bacteria. The results indicate that, as a physiological adaptation to the permanently cold Arctic environment, psychrophilic sulfate reducers have considerably higher specific metabolic rates than their mesophilic counterparts at similarly low temperatures.
Maximising and evaluating the uptake, use and impact of golf and health studies
Authors: Murray Andrew , Kelly Paul , Morton Sarah , Glover Danny , Duncan Jennifer , Hawkes Roger , Grant Liz , Mutrie Nanette 
Published: December 2019

Introduction
The dissemination of research, and evaluation of its impact is an increasing priority for the scientific community and funders. We take the topic of golf and health and aim to outline processes that may contribute to improved research uptake, use and impact proposing a research impact (RI) tool. We then evaluate our published research using the Research Contributions Framework (RCF).

Methods
Building on existing research and frameworks we i) assessed the need for, ii) carried out and iii) published research, before iv) creating digital resources, v) sharing these resources widely and vi) evaluating our research.
To evaluate uptake, use and impact of our three principal golf and health research outputs, we performed a contributions analysis, using the RCF first proposed by Morton.

Results/Discussion
We developed a specific six-step Research Impact tool. Having implemented this, research uptake and use included over 300 press articles, a dedicated website and social media channels. Golf’s global industry leadership dispersed information across >150 countries, embedded golf and health into curricula for industry professionals and used leading tournaments to promote health. National policy makers hosted dedicated meetings regarding golf and health and began to implement policy change.

Conclusion
To date, strong uptake and use can be demonstrated for these studies, while a final contribution to impact requires further time to determine.
Frameworks we used aiming to maximise impact (Research Impact tool) and evaluate its contribution to uptake, use and impact (Research Contribution Framework) could potentially add value to public health/sports medicine researchers.
Opportunities for antibiotic optimisation and outcome improvement in patients with negative blood cultures: study protocol for a cluster-randomised crossover trial, the NO-BACT study
Authors: Jiménez-Jorge Silvia , Palacios-Baena Zaira R , Rosso-Fernández Clara M , Girón-Ortega José A , Rodriguez-Baño Jesús , Retamar Pilar 
Published: December 2019

IntroductionPatients with negative blood cultures (BCx) represent 85%–90% of all patients with BCx taken during hospital admission. This population usually includes a heterogeneous group of patients admitted with infectious diseases or febrile syndromes that require a blood culture. There is very little evidence of the clinical characteristics and antibiotic treatment given to these patients.Methods and analysisIn a preliminary exploratory prospective cohort study of patients with BCx taken, the clinical/therapeutic characteristics and outcomes/antimicrobial stewardship opportunities of a population of patients with negative BCx will be analysed. In the second phase, using a cluster randomised crossover design, the implementation of an antimicrobial stewardship intervention targeting patients with negative BCx will be evaluated in terms of quality of antimicrobial use (duration and de-escalation), length of hospital stay and mortality.Ethics and disseminationThis study has been and registered with clinicaltrials.gov. The findings of our study may support the implementation in clinical practice of an antimicrobial stewardship intervention to optimise the use of antibiotics in patients with negative BCx. The results of this study will be published in peer-reviewed journals and disseminated at national and international conferences.Trial registration numberNCT03535324.