bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prymnesium parvum Population Dynamics During Bloom Development: A Role Assessment of Grazers and Virus1
Authors: Schwierzke Leslie , Roelke Daniel L. , Brooks Bryan W. , Grover James P. , Valenti Theodore W. , Lahousse Mieke , Miller Carrie J. , Pinckney James L. 
Published: February 2010

Schwierzke, Leslie, Daniel L. Roelke, Bryan W. Brooks, James P. Grover, Theodore W. Valenti, Jr., Mieke Lahousse, Carrie J. Miller, and James L. Pinckney, 2010. Prymnesium parvum Population Dynamics During Bloom Development: A Role Assessment of Grazers and Virus. Journal of the American Water Resources Association (JAWRA) 46(1):63‐75. DOI: 10.1111/j.1752‐1688.2009.00391.xAbstract:  The toxic haptophyte Prymnesium parvum is a harmful alga known to cause fish‐killing blooms that occur worldwide. In Texas (United States), P. parvum blooms occur in inland brackish water bodies and have increased in frequency and magnitude in recent years. In this study we conducted three consecutive field experiments (Lake Whitney) to investigate the influence of zooplankton and viruses on P. parvum bloom dynamics during the time of year when blooms are still typically active in Texas (early spring). A localized P. parvum bloom developed during our study that involved increasing levels of toxicity (based on Pimephales promelas and Daphnia magna bioassays). Only in our last experiment, during later stages of bloom development and under highly toxic conditions, did the presence of grazers show a statistically significant, negative effect on P. parvum population dynamics. During this experiment, a rotifer‐dominated zooplankton community emerged, composed mostly of Notholca laurentiae, suggesting that this species was less sensitive than other grazers to toxins produced by P. parvum. Microzooplankton may have also been important at this time. Similarly, only our final experiment demonstrated a statistically significant, negative effect of viruses on P. parvum. This exploratory study, resulting in observed impacts on P. parvum populations by both grazers and virus, enhances our understanding of P. parvum ecology and highlights direction for future studies on resistance of zooplankton to prymnesin toxins and algal‐virus interactions.
Factors Influencing Allelopathy and Toxicity in Prymnesium parvum1
Authors: Granéli Edna , Salomon Paulo S. 
Published: February 2010

Granéli, Edna and Paulo S. Salomon, 2010. Factors Influencing Allelopathy and Toxicity in Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):108‐120.Abstract:  Some microalgae are able to kill or inhibit nutrient‐competing microalgae, a process called allelopathy. Inhibiting or killing competitors enable these species to monopolize limiting resources, such as nitrogen and phosphorus. Prymnesium parvum is known to produce such allelopathic compounds, substances that seem identical to the ichthyotoxins identified from this species. Biotic and abiotic environmental factors influence not only growth rates but also toxin/allelopathic compounds production by P. parvum cells. Toxin production, as well as allelopathy, including grazer deterrence, increases dramatically in light, temperature, or nutrient stressed P. parvum cells. Correspondingly, toxicity and allelopathy may decrease, or cease completely, if cells are grown with high amounts of N and P in balanced proportions. However, even under nutrient (N and P) sufficient conditions, P. parvum is able to produce toxins/allelopathic compounds, with negative effects on other phytoplankton species or grazers, if cells densities of P. parvum are high relative to other species. This negative effect might shift the plankton community to more toxin resistant species. Filtrates from nutrient‐deficient P. parvum cultures have almost the same strong negative effect on grazers and other phytoplankton species as when Prymnesium cells are grown together with the target organisms. Eutrophication, the increased input of N and P to aquatic ecosystems, besides increasing nutrient concentrations, is usually provoking unbalanced N:P condition for the optimal growth of phytoplankton, deviating from the Redfield ratio, i.e., the phytoplankton cellular nitrogen to phosphorus ratio, N:P = 16:1 (by atoms) or 7.2:1 (by weight). Eutrophication thus both enhances P. parvum growth and increases production of toxins and allelopathic compounds. Supplying N‐deficient or P‐deficient P. parvum cells with the deficient nutrient reduces toxicity to less than half within 24 h after additions. As P. parvum is mixotrophic, uptake of dissolved or particulate organic N (DON or PON) can also reduce toxicity and allelopathy in the same manner as addition of inorganic N to N‐starved cells. In conclusion, P. parvum, by increasing its toxicity and allelopathic ability under poor environmental conditions, outcompetes the co‐occurring phytoplankton species.
Influence of Prey and Nutritional Status on the Rate of Nitrogen Uptake by Prymnesium parvum (haptophyte)1
Authors: Lindehoff Elin , Granéli Edna , Glibert Patricia M. 
Published: February 2010

Lindehoff, Elin, Edna Granéli, and Patricia M. Glibert, 2010. Influence of Prey and Nutritional Status on the Rate of Nitrogen Uptake by Prymnesium parvum (Haptophyte). Journal of the American Water Resources Association (JAWRA) 46(1):121‐132. DOI: 10.1111/j.1752‐1688.2009.00396.xAbstract:  We studied how the specific nitrogen (N) uptake rates of nitrate (NO3−), urea, and the amino acids, glutamic acid and glycine, by Prymnesium parvum were affected by (1) the change from N‐deficient status to N‐sufficient status of the P. parvum cells, (2) presence of prey from a natural Baltic Sea plankton community, and (3) the composition of prey as affected by additions of terrestrial originated dissolved organic matter (DOM) or inorganic nutrients. Nitrogen‐deficient P. parvum (16 μM NO3− and 4 μM PO4−, molar N:P ratio of 4:1) were mixed with a natural Baltic plankton community and given PO43− and (1) NO3− (control) or (2) high molecular weight DOM, >1 kDa concentrated from sewage effluent (+DOM), in a molar N:P ratio of 9‐10:1. With additions of 15N‐enriched substrates, rates of N uptake from NO3−, urea, and the amino acids glycine and glutamic acid were measured every 24 h for 72 h. Initial N‐deficient P. parvum were highly toxic (3.7 ± 0.9 × 10−4 mg Sap equiv/cell) and toxic allelochemicals were released into the medium causing the natural plankton community to lyse. Rates of N uptake differed between the “control” and the “+DOM” treatments over time; total (sum of the N substrates measured) absolute uptake rates (ρcell, fmol N/cell/h) at ambient culture conditions were significantly higher (ANOVA, p < 0.05) in the more toxic “control” treatments compared with the “+DOM” treatments after 48 h. In the “control” treatment, the total ρcell increased significantly (ANOVA, p < 0.01) from time 0 to 48 h, while in the “+DOM” treatment there was no significant increase. Released organic nutrients from the lysed plankton cells may have increased uptake rates of amino acids and urea by P. parvum. All uptake rates declined in all treatments by 72 h. Total dissolved N uptake rates at ambient culture conditions were estimated to make up about 10% of the N P. parvum are potentially capable of ingesting from particulate prey.
Iron-Corroding Methanogen Isolated from a Crude-Oil Storage Tank
Authors: Uchiyama Taku , Ito Kimio , Mori Koji , Tsurumaru Hirohito , Harayama Shigeaki 
Published: January 2010

ABSTRACT

Microbiologically influenced corrosion of steel in anaerobic environments has been attributed to hydrogenotrophic microorganisms. A sludge sample collected from the bottom plate of a crude-oil storage tank was used to inoculate a medium containing iron (Fe
0
) granules, which was then incubated anaerobically at 37°C under an N
2
-CO
2
atmosphere to enrich for microorganisms capable of using iron as the sole source of electrons. A methanogen, designated strain KA1, was isolated from the enrichment culture. An analysis of its 16S rRNA gene sequence revealed that strain KA1 is a
Methanococcus maripaludis
strain. Strain KA1 produced methane and oxidized iron much faster than did the type strain of
M. maripaludis
, strain JJ
T
, which produced methane at a rate expected from the abiotic H
2
production rate from iron. Scanning electron micrographs of iron coupons that had been immersed in either a KA1 culture, a JJ
T
culture, or an aseptic medium showed that only coupons from the KA1 culture had corroded substantially, and these were covered with crystalline deposits that consisted mainly of FeCO
3
.
Alkaloid Cluster Gene
ccsA
of the Ergot Fungus
Claviceps purpurea
Encodes Chanoclavine I Synthase, a Flavin Adenine Dinucleotide-Containing Oxidoreductase Mediating the Transformation of
N
-Methyl-Dimethylallyltryptophan to Chanoclavine I
Authors: Lorenz Nicole , Olšovská Jana , Šulc Miroslav , Tudzynski Paul 
Published: January 2010

ABSTRACT

Ergot alkaloids are indole-derived secondary metabolites synthesized by the phytopathogenic ascomycete
Claviceps purpurea
. In wild-type strains, they are exclusively produced in the sclerotium, a hibernation structure; for biotechnological applications, submerse production strains have been generated by mutagenesis. It was shown previously that the enzymes specific for alkaloid biosynthesis are encoded by a gene cluster of 68.5 kb. This ergot alkaloid cluster consists of 14 genes coregulated and expressed under alkaloid-producing conditions. Although the role of some of the cluster genes in alkaloid biosynthesis could be confirmed by a targeted knockout approach, further functional analyses are needed, especially concerning the early pathway-specific steps up to the production of clavine alkaloids. Therefore, the gene
ccsA
, originally named
easE
and preliminarily annotated as coding for a flavin adenine dinucleotide-containing oxidoreductase, was deleted in the
C. purpurea
strain P1, which is able to synthesize ergot alkaloids in axenic culture. Five independent knockout mutants were analyzed with regard to alkaloid-producing capability. Thin-layer chromatography (TLC), ultrapressure liquid chromatography (UPLC), and mass spectrometry (MS) analyses revealed accumulation of
N
-methyl-dimethylallyltryptophan (Me-DMAT) and traces of dimethylallyltryptophan (DMAT), the first pathway-specific intermediate. Since other alkaloid intermediates could not be detected, we conclude that deletion of
ccsA
led to a block in alkaloid biosynthesis beyond Me-DMAT formation. Complementation with a
ccsA
/
gfp
fusion construct restored alkaloid biosynthesis. These data indicate that
ccsA
encodes the chanoclavine I synthase or a component thereof catalyzing the conversion of
N
-methyl-dimethylallyltryptophan to chanoclavine I.
Genes Involved in
Cronobacter sakazakii
Biofilm Formation
Authors: Hartmann Isabel , Carranza Paula , Lehner Angelika , Stephan Roger , Eberl Leo , Riedel Kathrin 
Published: January 2010

ABSTRACT

Cronobacter
spp. are opportunistic food-borne pathogens that can cause severe and sometimes lethal infections in neonates. In some outbreaks, the sources of infection were traced to contaminated powdered infant formula (PIF) or contaminated utensils used for PIF reconstitution. In this study, we investigated biofilm formation in
Cronobacter sakazakii
strain ES5. To investigate the genetic basis of biofilm formation in
Cronobacter
on abiotic surfaces, we screened a library of random transposon mutants of strain ES5 for reduced biofilm formation using a polystyrene microtiter assay. Genetic characterization of the mutants led to identification of genes that are associated with cellulose biosynthesis and flagellar structure and biosynthesis and genes involved in basic cellular processes and virulence, as well as several genes whose functions are currently unknown. In two of the mutants, hypothetical proteins ESA_00281 and ESA_00282 had a strong impact on flow cell biofilm architecture, and their contribution to biofilm formation was confirmed by genetic complementation. In addition, adhesion of selected biofilm formation mutants to Caco-2 intestinal epithelial cells was investigated. Our findings suggest that flagella and hypothetical proteins ESA_00281 and ESA_00282, but not cellulose, contribute to adhesion of
Cronobacter
to this biotic surface.
Cleavage of Zearalenone byTrichosporon mycotoxinivoransto a Novel Nonestrogenic Metabolite
Authors: Vekiru Elisavet , Hametner Christian , Mitterbauer Rudolf , Rechthaler Justyna , Adam Gerhard , Schatzmayr Gerd , Krska Rudolf , Schuhmacher Rainer 
Published: January 2010

ABSTRACTZearalenone (ZON) is a potent estrogenic mycotoxin produced by severalFusariumspecies most frequently on maize and therefore can be found in food and animal feed. Since animal production performance is negatively affected by the presence of ZON, its detoxification in contaminated plant material or by-products of bioethanol production would be advantageous. Microbial biotransformation into nontoxic metabolites is one promising approach. In this study the main transformation product of ZON formed by the yeastTrichosporon mycotoxinivoranswas identified and characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and LC-diode array detector (DAD) analysis. The metabolite, named ZOM-1, was purified, and its molecular formula, C18H24O7, was established by time of flight MS (TOF MS) from the ions observed atm/z351.1445 [M-H]−and atm/z375.1416 [M+Na]+. Employing nuclear magnetic resonance (NMR) spectroscopy, the novel ZON metabolite was finally identified as (5S)-5-({2,4-dihydroxy-6-[(1E)-5-hydroxypent-1-en-1-yl]benzoyl}oxy)hexanoic acid. The structure of ZOM-1 is characterized by an opening of the macrocyclic ring of ZON at the ketone group at C6′. ZOM-1 did not show estrogenic activity in a sensitive yeast bioassay, even at a concentration 1,000-fold higher than that of ZON and did not interact with the human estrogen receptor in anin vitrocompetitive binding assay.
Identification of Pathogenic
Vibrio
Species by Multilocus PCR-Electrospray Ionization Mass Spectrometry and Its Application to Aquatic Environments of the Former Soviet Republic of Georgia
Authors: Whitehouse Chris A. , Baldwin Carson , Sampath Rangarajan , Blyn Lawrence B. , Melton Rachael , Li Feng , Hall Thomas A. , Harpin Vanessa , Matthews Heather , Tediashvili Marina , Jaiani Ekaterina , Kokashvili Tamar , Janelidze Nino , Grim Christopher , Colwell Rita R. , Huq Anwar 
Published: January 2010

ABSTRACT

The Ibis T5000 is a novel diagnostic platform that couples PCR and mass spectrometry. In this study, we developed an assay that can identify all known pathogenic
Vibrio
species and field-tested it using natural water samples from both freshwater lakes and the Georgian coastal zone of the Black Sea. Of the 278 total water samples screened, 9 different
Vibrio
species were detected, 114 (41%) samples were positive for
V. cholerae
, and 5 (0.8%) samples were positive for the cholera toxin A gene (
ctxA
). All
ctxA
-positive samples were from two freshwater lakes, and no
ctxA
-positive samples from any of the Black Sea sites were detected.
Plasmid pAMI2 of
Paracoccus aminophilus
JCM 7686 Carries
N
,
N
-Dimethylformamide Degradation-Related Genes Whose Expression Is Activated by a LuxR Family Regulator
Authors: Dziewit Lukasz , Dmowski Michal , Baj Jadwiga , Bartosik Dariusz 
Published: January 2010

ABSTRACT

N
,
N
-Dimethylformamide (DMF), a toxic solvent used in the chemical industry, is frequently present in industrial wastes. Plasmid pAMI2 (18.6 kb) of
Paracoccus aminophilus
JCM 7686 carries genetic information which is crucial for methylotrophic growth of this bacterium, using DMF as the sole source of carbon and energy. Besides a conserved backbone related to pAgK84 of
Agrobacterium radiobacter
K84, pAMI2 carries a three-gene cluster coding for the protein DmfR, which has sequence similarities to members of the LuxR family of transcription regulators, and two subunits (DmfA1 and DmfA2) of
N
,
N
-dimethylformamidase, an enzyme of high substrate specificity that catalyzes the first step in the degradation of DMF. Genetic analysis revealed that these genes, which are all placed in the same orientation, constitute an inducible operon whose expression is activated in the presence of DMF by the positive transcription regulator DmfR. This operon was used to construct a strain able to degrade DMF at high concentrations that might be used in the biotreatment of DMF-containing industrial wastewaters. To our knowledge, this is the first study to provide insights into the genetic organization and regulation as well as the dissemination in bacteria of genes involved in the enzymatic breakdown of DMF.
Detection and Quantification of Infectious Avian Influenza A (H5N1) Virus in Environmental Water by Using Real-Time Reverse Transcription-PCR
Authors: Dovas C. I. , Papanastassopoulou M. , Georgiadis M. P. , Chatzinasiou E. , Maliogka V. I. , Georgiades G. K. 
Published: January 2010

ABSTRACT

Routes of avian influenza virus (AIV) dispersal among aquatic birds involve direct (bird-to-bird) and indirect (waterborne) transmission. The environmental persistence of H5N1 virus in natural water reservoirs can be assessed by isolation of virus in embryonated chicken eggs. Here we describe development and evaluation of a real-time quantitative reverse transcription (RT)-PCR (qRT-PCR) method for detection of H5N1 AIV in environmental water. This method is based on adsorption of virus particles to formalin-fixed erythrocytes, followed by qRT-PCR detection. The numbers of hemagglutinin RNA copies from H5N1 highly pathogenic AIV particles adsorbed to erythrocytes detected correlated highly with the infectious doses of the virus that were determined for three different types of artificially inoculated environmental water over a 17-day incubation period. The advantages of this method include detection and quantification of infectious H5N1 AIVs with a high level of sensitivity, a wide dynamic range, and reproducibility, as well as increased biosecurity. The lowest concentration of H5N1 virus that could be reproducibly detected was 0.91 50% egg infective dose per ml. In addition, a virus with high virion stability (
Tobacco mosaic virus
) was used as an internal control to accurately monitor the efficiency of RNA purification, cDNA synthesis, and PCR amplification for each individual sample. This detection system could be useful for rapid high-throughput monitoring for the presence of H5N1 AIVs in environmental water and in studies designed to explore the viability and epidemiology of these viruses in different waterfowl ecosystems. The proposed method may also be adapted for detection of other AIVs and for assessment of their prevalence and distribution in environmental reservoirs.
Mucosal Adhesion Properties of the ProbioticLactobacillus rhamnosusGG SpaCBA and SpaFED Pilin Subunits
Authors: von Ossowski Ingemar , Reunanen Justus , Satokari Reetta , Vesterlund Satu , Kankainen Matti , Huhtinen Heikki , Tynkkynen Soile , Salminen Seppo , de Vos Willem M. , Palva Airi 
Published: January 2010

ABSTRACTLactobacillus rhamnosusGG is a well-established Gram-positive probiotic strain, whose health-benefiting properties are dependent in part on prolonged residence in the gastrointestinal tract and are likely dictated by adherence to the intestinal mucosa. Previously, we identified two pilus gene clusters (spaCBAandspaFED) in the genome of this probiotic bacterium, each of which contained the predicted genes for three pilin subunits and a single sortase. We also confirmed the presence of SpaCBA pili on the cell surface and attributed an intestinal mucus-binding capacity to one of the pilin subunits (SpaC). Here, we report cloning of the remaining pilin genes (spaA,spaB,spaD,spaE, andspaF) inEscherichia coli, production and purification of the recombinant proteins, and assessment of the adherence of these proteins to human intestinal mucus. Our findings indicate that the SpaB and SpaF pilin subunits also exhibit substantial binding to mucus, which can be inhibited competitively in a dose-related manner. Moreover, the binding between the SpaB pilin subunit and the mucosal substrate appears to operate through electrostatic contacts and is not related to a recognized mucus-binding domain. We conclude from these results that it is conceivable that two pilin subunits (SpaB and SpaC) in the SpaCBA pilus fiber play a role in binding to intestinal mucus, but for the uncharacterized and putative SpaFED pilus fiber only a single pilin subunit (SpaF) is potentially responsible for adhesion to mucus.
Evolutionary Dynamics of Clustered Irregularly Interspaced Short Palindromic Repeat Systems in the Ocean Metagenome
Authors: Sorokin Valery A. , Gelfand Mikhail S. , Artamonova Irena I. 
Published: January 2010

ABSTRACTClustered regularly interspaced short palindromic repeats (CRISPRs) form a recently characterized type of prokaryotic antiphage defense system. The phage-host interactions involving CRISPRs have been studied in experiments with selected bacterial or archaeal species and, computationally, in completely sequenced genomes. However, these studies do not allow one to take prokaryotic population diversity and phage-host interaction dynamics into account. This gap can be filled by using metagenomic data: in particular, the largest existing data set, generated from theSorcerer IIGlobal Ocean Sampling expedition. The application of three publicly available CRISPR recognition programs to the Global Ocean metagenome produced a large proportion of false-positive results. To address this problem, a filtering procedure was designed. It resulted in about 200 reliable CRISPR cassettes, which were then studied in detail. The repeat consensuses were clustered into several stable classes that differed from the existing classification. Short fragments of DNA similar to the cassette spacers were more frequently present in the same geographical location than in other locations (P, <0.0001). We developed a catalogue of elementary CRISPR-forming events and reconstructed the likely evolutionary history of cassettes that had common spacers. Metagenomic collections allow for relatively unbiased analysis of phage-host interactions and CRISPR evolution. The results of this study demonstrate that CRISPR cassettes retain the memory of the local virus population at a particular ocean location. CRISPR evolution may be described using a limited vocabulary of elementary events that have a natural biological interpretation.