bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphologic, Host Specificity, and Molecular Characterization of a HungarianCryptosporidium meleagridisIsolate
Authors: Sréter Tamás , Kovács Gábor , da Silva Alexandre J. , Pieniazek Norman J. , Széll Zoltán , Dobos-Kovács Mihály , Márialigeti Károly , Varga István 
Published: July 2002

ABSTRACTThis study was undertaken in order to characterizeCryptosporidium meleagridisisolated from a turkey in Hungary and to compare the morphologies, host specificities, organ locations, and small-subunit RNA (SSU rRNA) gene sequences of this organism and otherCryptosporidiumspecies. The phenotypic differences betweenC. meleagridisandCryptosporidium parvumHungarian calf isolate (zoonotic genotype) oocysts were small, although they were statistically significant. Oocysts ofC. meleagridiswere successfully passaged in turkeys and were transmitted from turkeys to immunosuppressed mice and from mice to chickens. The location ofC. meleagridiswas the small intestine, like the location ofC. parvum. A comparison of sequence data for the variable region of the SSU rRNA gene ofC. meleagridisisolated from turkeys with otherCryptosporidiumsequence data in the GenBank database revealed that the HungarianC. meleagridissequence is identical to aC. meleagridissequence recently described for a North Carolina isolate. Thus,C. meleagridisis a distinct species that occurs worldwide and has a broad host range, like theC. parvumzoonotic strain (also called the calf or bovine strain) andCryptosporidium felis. Because birds are susceptible toC. meleagridisand to some zoonotic strains ofC. parvum, these animals may play an active role in contamination of surface waters not only withCryptosporidium baileyibut also withC. parvum-like parasites.
Electricity Generation in Microbial Fuel Cells Using Neutral Red as an Electronophore
Authors: Park Doo Hyun , Zeikus J. Gregory 
Published: July 2002

ABSTRACT

Neutral red (NR) was utilized as an electron mediator in microbial fuel cells consuming glucose to study both its efficiency during electricity generation and its role in altering anaerobic growth and metabolism of
Escherichia coli
and
Actinobacillus succinogenes
. A study of chemical fuel cells in which NADH, NR, and ferricyanide were the electron donor, the electronophore, and the electron acceptor, respectively, showed that electrical current produced from NADH was proportional to the concentration of NADH. Fourfold more current was produced from NADH in chemical fuel cells when NR was the electron mediator than when thionin was the electron mediator. In microbial fuel cells in which
E. coli
resting cells were used the amount of current produced from glucose when NR was the electron mediator (3.5 mA) was 10-fold more than the amount produced when thionin was the electron mediator (0.4 mA). The amount of electrical energy generated (expressed in joules per mole of substrate) and the amount of current produced from glucose (expressed in milliamperes) in NR-mediated microbial fuel cells containing either
E. coli
or
A. succinogenes
were about 10- and 2-fold greater, respectively, when resting cells were used than when growing cells were used. Cell growth was inhibited substantially when these microbial fuel cells were making current, and more oxidized end products were formed under these conditions. When sewage sludge (i.e., a mixed culture of anaerobic bacteria) was used in the fuel cell, stable (for 120 h) and equivalent levels of current were obtained with glucose, as observed in the pure-culture experiments. These results suggest that NR is better than other electron mediators used in microbial fuel cells and that sludge production can be decreased while electricity is produced in fuel cells. Our results are discussed in relation to factors that may improve the relatively low electrical efficiencies (1.2 kJ/mol) obtained with microbial fuel cells.
Increased Growth of the Microalga
Chlorella vulgaris
when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium
Azospirillum brasilense
Authors: Gonzalez Luz E. , Bashan Yoav 
Published: July 2002

ABSTRACT

Coimmobilization of the freshwater microalga
Chlorella vulgaris
and the plant-growth-promoting bacterium
Azospirillum brasilense
in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of
A. brasilense
. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments.
Reduction of Fe(III), Cr(VI), U(VI), and Tc(VII) by
Deinococcus radiodurans
R1
Authors: Fredrickson J. K. , Kostandarithes H. M. , Li S. W. , Plymale A. E. , Daly M. J. 
Published: July 2002

ABSTRACT

Deinococcus radiodurans
is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions,
D. radiodurans
R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO
2
and acetate but was unable to link this process to growth.
D. radiodurans
reduced the humic acid analog anthraquinone-2,6-disulfonate (AQDS) to its dihydroquinone form, AH
2
DS, which subsequently transferred electrons to the Fe(III) oxides hydrous ferric oxide and goethite via a previously described electron shuttle mechanism.
D. radiodurans
reduced the solid-phase Fe(III) oxides in the presence of either 0.1 mM AQDS or leonardite humic acids (2 mg ml
−1
) but not in their absence.
D. radiodurans
also reduced U(VI) and Tc(VII) in the presence of AQDS. In contrast, Cr(VI) was directly reduced in anaerobic cultures with lactate although the rate of reduction was higher in the presence of AQDS. The results are the first evidence that
D. radiodurans
can reduce Fe(III) coupled to the oxidation of lactate or other organic compounds. Also,
D. radiodurans
, in combination with humic acids or synthetic electron shuttle agents, can reduce U and Tc and thus has potential applications for remediation of metal- and radionuclide-contaminated sites where ionizing radiation or other DNA-damaging agents may restrict the activity of more sensitive organisms.
Identification and Characterization of Three Differentially Expressed Genes, Encoding
S
-Adenosylhomocysteine Hydrolase, Methionine Aminopeptidase, and a Histone-Like Protein, in the Toxic Dinoflagellate
Alexandrium fundyense
Authors: Taroncher-Oldenburg Gaspar , Anderson Donald M. 
Published: July 2002

ABSTRACT

Genes showing differential expression related to the early G
1
phase of the cell cycle during synchronized circadian growth of the toxic dinoflagellate
Alexandrium fundyense
were identified and characterized by differential display (DD). The determination in our previous work that toxin production in
Alexandrium
is relegated to a narrow time frame in early G
1
led to the hypothesis that transcriptionally up- or downregulated genes during this subphase of the cell cycle might be related to toxin biosynthesis. Three genes, encoding
S
-adenosylhomocysteine hydrolase (
Sahh
), methionine aminopeptidase (
Map
), and a histone-like protein (
HAf
), were isolated.
Sahh
was downregulated, while
Map
and
HAf
were upregulated, during the early G
1
phase of the cell cycle.
Sahh
and
Map
encoded amino acid sequences with about 90 and 70% similarity to those encoded by several eukaryotic and prokaryotic
Sahh
and
Map
genes, respectively. The partial
Map
sequence also contained three cobalt binding motifs characteristic of all
Map
genes.
HAf
encoded an amino acid sequence with 60% similarity to those of two histone-like proteins from the dinoflagellate
Crypthecodinium cohnii
Biecheler. This study documents the potential of applying DD to the identification of genes that are related to physiological processes or cell cycle events in phytoplankton under conditions where small sample volumes represent an experimental constraint. The identification of an additional 21 genes with various cell cycle-related DD patterns also provides evidence for the importance of pretranslational or transcriptional regulation in dinoflagellates, contrary to previous reports suggesting the possibility that translational mechanisms are the primary means of circadian regulation in this group of organisms.
The Macrocyclic Peptide Antibiotic Micrococcin P1Is Secreted by the Food-Borne BacteriumStaphylococcus equorumWS 2733 and InhibitsListeria monocytogeneson Soft Cheese
Authors: Carnio Markus C. , Höltzel Alexandra , Rudolf Melanie , Henle Thomas , Jung Günther , Scherer Siegfried 
Published: July 2002

ABSTRACTStaphylococcus equorumWS 2733 was found to produce a substance exhibiting a bacteriostatic effect on a variety of gram-positive bacteria. The metabolite was purified to homogeneity by ammonium sulfate precipitation and semipreparative reversed-phase high-performance liquid chromatography. Electrospray mass spectrometry confirmed the high purity of the compound and revealed a molecular mass of 1,143 Da. By two-dimensional nuclear magnetic resonance spectroscopy the substance was identified as micrococcin P1which is a macrocyclic peptide antibiotic that has not yet been reported for the genusStaphylococcus. A total of 95 out of 95Listeriastrains and 130 out of 135 other gram-positive bacteria were inhibited by this substance, while none of 37 gram-negative bacteria were affected. The antilisterial potential of this food-grade strain as a protective starter culture was evaluated by its in situ application in cheese-ripening experiments under laboratory conditions. A remarkable growth reduction ofListeria monocytogenescould be achieved compared to control cheese ripened with a nonbacteriocinogenic type strain ofStaphylococcus equorum. In order to prove that inhibition was due to micrococcin P1, a micrococcin-deficient mutant was constructed which did not inhibitL. monocytogenesin cheese-ripening experiments.
Cloning the Soil Metagenome: a Strategy for Accessing the Genetic and Functional Diversity of Uncultured Microorganisms
Authors: Rondon Michelle R. , August Paul R. , Bettermann Alan D. , Brady Sean F. , Grossman Trudy H. , Liles Mark R. , Loiacono Kara A. , Lynch Berkley A. , MacNeil Ian A. , Minor Charles , Tiong Choi Lai , Gilman Michael , Osburne Marcia S. , Clardy Jon , Handelsman Jo , Goodman Robert M. 
Published: July 2002

ABSTRACT

Recent progress in molecular microbial ecology has revealed that traditional culturing methods fail to represent the scope of microbial diversity in nature, since only a small proportion of viable microorganisms in a sample are recovered by culturing techniques. To develop methods to investigate the full extent of microbial diversity, we used a bacterial artificial chromosome (BAC) vector to construct libraries of genomic DNA isolated directly from soil (termed metagenomic libraries). To date, we have constructed two such libraries, which contain more than 1 Gbp of DNA. Phylogenetic analysis of 16S rRNA gene sequences recovered from one of the libraries indicates that the BAC libraries contain DNA from a wide diversity of microbial phyla, including sequences from diverse taxa such as the low-G+C, gram-positive
Acidobacterium
,
Cytophagales
, and
Proteobacteria
. Initial screening of the libraries in
Escherichia coli
identified several clones that express heterologous genes from the inserts, confirming that the BAC vector can be used to maintain, express, and analyze environmental DNA. The phenotypes expressed by these clones include antibacterial, lipase, amylase, nuclease, and hemolytic activities. Metagenomic libraries are a powerful tool for exploring soil microbial diversity, providing access to the genetic information of uncultured soil microorganisms. Such libraries will be the basis of new initiatives to conduct genomic studies that link phylogenetic and functional information about the microbiota of environments dominated by microorganisms that are refractory to cultivation.
Isolation of Methyl Parathion-Degrading Strain M6 and Cloning of the Methyl Parathion Hydrolase Gene
Authors: Zhongli Cui , Shunpeng Li , Guoping Fu 
Published: July 2002

ABSTRACT

A degradative bacterium, M6, was isolated and presumptively identified as
Plesiomonas
sp. strain M6 was able to hydrolyze methyl parathion to
p
-nitrophenol. A novel organophosphate hydrolase gene designated
mpd
was selected from its genomic library prepared by shotgun cloning. The nucleotide sequence of the
mpd
gene was determined. The gene could be effectively expressed in
Esherichia coli
.
Bacillus thuringiensis
Delta-Endotoxin Cry1 Hybrid Proteins with Increased Activity against the Colorado Potato Beetle
Authors: Naimov Samir , Weemen-Hendriks Mieke , Dukiandjiev Stefan , de Maagd Ruud A. 
Published: July 2002

ABSTRACT

Cry1 delta-endotoxins of
Bacillus thuringiensis
are generally active against lepidopteran insects, but Cry1Ba and Cry1Ia have additional, though low, levels of activity against coleopterans such as the Colorado potato beetle. Here we report the construction of Cry1Ba/Cry1Ia hybrid toxins which have increased activities against this insect species.
Detection of Hepatitis A Virus by the Nucleic Acid Sequence-Based Amplification Technique and Comparison with Reverse Transcription-PCR
Authors: Jean Julie , Blais Burton , Darveau André , Fliss Ismaı̈l 
Published: July 2002

ABSTRACT

A nucleic acid sequence-based amplification (NASBA) technique for the detection of hepatitis A virus (HAV) in foods was developed and compared to the traditional reverse transcription (RT)-PCR technique. Oligonucleotide primers targeting the VP1 and VP2 genes encoding the major HAV capsid proteins were used for the amplification of viral RNA in an isothermal process resulting in the accumulation of RNA amplicons. Amplicons were detected by hybridization with a digoxigenin-labeled oligonucleotide probe in a dot blot assay format. Using the NASBA, as little as 0.4 ng of target RNA/ml was detected per comparison to 4 ng/ml for RT-PCR. When crude HAV viral lysate was used, a detection limit of 2 PFU (4 × 10
2
PFU/ml) was obtained with NASBA, compared to 50 PFU (1 × 10
4
PFU/ml) obtained with RT-PCR. No interference was encountered in the amplification of HAV RNA in the presence of excess nontarget RNA or DNA. The NASBA system successfully detected HAV recovered from experimentally inoculated samples of waste water, lettuce, and blueberries. Compared to RT-PCR and other amplification techniques, the NASBA system offers several advantages in terms of sensitivity, rapidity, and simplicity. This technique should be readily adaptable for detection of other RNA viruses in both foods and clinical samples.
Identification and Cloning of
gusA
, Encoding a New β-Glucuronidase from
Lactobacillus gasseri
ADH
Authors: Russell W. M. , Klaenhammer T. R. 
Published: July 2002

ABSTRACT

The
gusA
gene, encoding a new β-glucuronidase enzyme, has been cloned from
Lactobacillus gasseri
ADH. This is the first report of a β-glucuronidase gene cloned from a bacterial source other than
Escherichia coli
. A plasmid library of
L. gasseri
chromosomal DNA was screened for complementation of an
E. coli gus
mutant. Two overlapping clones that restored β-glucuronidase activity in the mutant strain were sequenced and revealed three complete and two partial open reading frames. The largest open reading frame, spanning 1,797 bp, encodes a 597-amino-acid protein that shows 39% identity to β-glucuronidase (GusA) of
E. coli
K-12 (EC
3.2.1.31
). The other two complete open reading frames, which are arranged to be separately transcribed, encode a putative bile salt hydrolase and a putative protein of unknown function with similarities to MerR-type regulatory proteins. Overexpression of GusA was achieved in a β-glucuronidase-negative
L. gasseri
strain by expressing the
gusA
gene, subcloned onto a low-copy-number shuttle vector, from the strong
Lactobacillus
P6 promoter. GusA was also expressed in
E. coli
from a pET expression system. Preliminary characterization of the GusA protein from crude cell extracts revealed that the enzyme was active across an acidic pH range and a broad temperature range. An analysis of other lactobacilli identified β-glucuronidase activity and
gusA
homologs in other
L. gasseri
isolates but not in other
Lactobacillus
species tested.
Species-Specific, Nested PCR-Restriction Fragment Length Polymorphism Detection of Single
Cryptosporidium parvum
Oocysts
Authors: Sturbaum Gregory D. , Reed Carrie , Hoover Paul J. , Jost B. Helen , Marshall Marilyn M. , Sterling Charles R. 
Published: July 2002

ABSTRACT

Concurrent with recent advances seen with
Cryptosporidium parvum
detection in both treated and untreated water is the need to properly evaluate these advances. A micromanipulation method by which known numbers of
C. parvum
oocysts, even a single oocyst, can be delivered to a test matrix for detection sensitivity is presented. Using newly developed nested PCR-restriction fragment length polymorphism primers, PCR sensitivity was evaluated with 1, 2, 3, 4, 5, 7, or 10 oocysts. PCR detection rates (50 samples for each number of oocysts) ranged from 38% for single oocysts to 92% for 5 oocysts, while 10 oocysts were needed to achieve 100% detection. The nested PCR conditions amplified products from
C. parvum
,
Cryptosporidium baileyi
, and
Cryptosporidium serpentis
but no other
Cryptosporidium
sp. or protozoan tested. Restriction enzyme digestion with
Vsp
I distinguished between
C. parvum
genotypes 1 and 2. Restriction enzyme digestion with
Dra
II distinguished
C. parvum
from
C. baileyi
and
C. serpentis
. Use of known numbers of whole oocysts encompasses the difficulty of liberating DNA from the oocyst and eliminates the standard deviation inherent within a dilution series. To our knowledge this is the first report in which singly isolated
C. parvum
oocysts were used to evaluate PCR sensitivity. This achievement illustrates that PCR amplification of a single oocyst is feasible, yet sensitivity remains an issue, thereby illustrating the difficulty of dealing with low oocyst numbers when working with environmental water samples.
Protection of Tomato Seedlings against Infection by
Pseudomonas syringae
pv. Tomato by Using the Plant Growth-Promoting Bacterium
Azospirillum brasilense
Authors: Bashan Yoav , de-Bashan Luz E. 
Published: July 2002

ABSTRACT

Pseudomonas syringae
pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium
Azospirillum brasilense
were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the
A. brasilense
population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of
P. syringae
pv. tomato (10
7
versus 10
5
CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of
P. syringae
pv. tomato was 1 order of magnitude greater than that of
A. brasilense
(10
7
versus 10
6
CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the
A. brasilense
population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the
P. syringae
pv. tomato population and significantly decreased disease severity. Challenge with
P. syringae
pv. tomato after
A. brasilense
was established in the leaves further reduced both the population of
P. syringae
pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (10
5
to 10
6
CFU/g [dry weight] of root). However,
P. syringae
pv. tomato did not survive in the rhizosphere in the presence of
A. brasilense
. Foliar inoculation of
A. brasilense
after
P. syringae
pv. tomato was established on the leaves did not alleviate bacterial speck disease, and
A. brasilense
did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of
A. brasilense
(>10
8
CFU/g [dry weight] of leaf), decreased the population of
P. syringae
pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that
A. brasilense
be used in prevention programs to combat the foliar bacterial speck disease caused by
P. syringae
pv. tomato.
Chi18A, the Endochitinase in the Cellulosome of the Thermophilic, Cellulolytic Bacterium
Clostridium thermocellum
Authors: Zverlov Vladimir V. , Fuchs Klaus-Peter , Schwarz Wolfgang H. 
Published: July 2002

ABSTRACT

The chitinase gene
chiA
was identified on the
Clostridium thermocellum
genome downstream of the endoglucanase gene
celA
. It contains a catalytic module of glycosyl hydrolase family 18 and a cellulosomal dockerin module. Chi18A hydrolyzes aryl-acetyl-chito-oligosaccharides preferentially. In denaturing electrophoresis of purified cellulosomes, a single chitinase activity band was identified in zymograms and Western blots, indicating that Chi18A is the only chitinase in the cellulosome.
Cytokine Gene Expression Occurs More Rapidly in Stimulated Peripheral Blood Mononuclear Cells from Human Immunodeficiency Virus-Infected Persons
Authors: Breen Elizabeth Crabb , McDonald Matthew , Fan Jiang , Boscardin John , Fahey John L. 
Published: July 2002

ABSTRACTEvaluation of cytokine gene expression following in vitro stimulation is one means of examining the dysregulation of the immune system in human immunodeficiency virus (HIV) infection. We have assessed differences in the immune status of non-HIV-infected (HIV−) and HIV-infected (HIV+) individuals by evaluating the kinetics of the expression of cytokine genes. We compared detailed time courses of cytokine mRNA expression in HIV− and HIV+ peripheral blood mononuclear cells (PBMC) and found that there is a significant shift (P< 0.01) for all cytokines examined (interleukin 2 [IL-2], IL-6, IL-10, gamma interferon, and tumor necrosis factor alpha [TNF-α]) to an earlier time of mean peak mRNA expression by HIV+ PBMC (between 4 and 8 h) compared to HIV− PBMC (8 h) in response to either phytohemagglutinin (PHA) or anti-CD3 stimulation. Additional studies showed that although PHA-stimulated HIV+ PBMC showed decreased median IL-2, IL-4, and TNF-α mRNA levels, they typically demonstrated more rapid kinetics (increased mean 4-h/24-h cytokine mRNA ratios), with significant differences for IL-4 (P< 0.05) and TNF-α (P< 0.005), compared to HIV− PBMC. The use of fresh or frozen cells gave comparable cytokine mRNA data; however, the secretion of some cytokine proteins (IL-2 receptor, IL-10, and TNF-α) appeared to be reduced in HIV+ PBMC that had been frozen and thawed. Our studies demonstrate that the kinetics of cytokine gene expression can reveal additional dysregulation of the immune system in HIV infection, suggesting that PBMC of HIV-infected persons exist in an activated state in vivo that permits them to express cytokine genes more rapidly than a normal PBMC.