bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of Bacteriophages Specific to a Fish Pathogen,
Pseudomonas plecoglossicida
, as a Candidate for Disease Control
Authors: Park Se Chang , Shimamura Ichiro , Fukunaga Minoru , Mori Koh-Ichiro , Nakai Toshihiro 
Published: July 2002

ABSTRACT

Two types of bacteriophage specific to
Pseudomonas plecoglossicida
, the causative agent of bacterial hemorrhagic ascites disease in cultured ayu fish (
Plecoglossus altivelis
), were isolated from diseased ayu and the rearing pond water. One type of phage, which formed small plaques, was tentatively classified as a member of the family
Myoviridae
, and the other type, which formed large plaques, was classified as a member of the family
Podoviridae
. All 27 strains of
P. plecoglossicida
examined, which were isolated from diseased ayu from geographically different areas in 1991 to 1999, exhibited quite similar sensitivities to either type of phage. One strain of
P. plecoglossicida
was highly virulent for ayu, and the 50% lethal dose (LD
50
) when intramuscular injection was used was 10
1.2
CFU fish
−1
; in contrast, phage-resistant variants of this organism were less virulent (LD
50
, >10
4
CFU fish
−1
). Oral administration of phage-impregnated feed to ayu resulted in protection against experimental infection with
P. plecoglossicida
. After oral administration of
P. plecoglossicida
cells of this bacterium were always detected in the kidneys of control fish that did not receive the phage treatment, while the cells quickly disappeared from the phage-treated fish. Bacterial growth in freshwater was lower in the presence of phage, and the number of phage PFU increased rapidly. These results suggest that it may be possible to use phage to control the disease caused by
P. plecoglossicida
.
Method for Rapid Purification of Class IIa Bacteriocins and Comparison of Their Activities
Authors: Guyonnet D. , Fremaux C. , Cenatiempo Y. , Berjeaud J. M. 
Published: July 2002

ABSTRACT

A three-step method was developed for the purification of mesentericin Y105 (60% yield) from the culture supernatant of
Leuconostoc mesenteroides
Y105. The same procedure was successfully applied to the purification of five other anti-
Listeria
bacteriocins identified by mass spectrometry. Specific activities of the purified bacteriocins were compared.
Microbial Life beneath a High Arctic Glacier
Authors: Skidmore Mark L. , Foght Julia M. , Sharp Martin J. 
Published: July 2002

ABSTRACT

The debris-rich basal ice layers of a high Arctic glacier were shown to contain metabolically diverse microbes that could be cultured oligotrophically at low temperatures (0.3 to 4°C). These organisms included aerobic chemoheterotrophs and anaerobic nitrate reducers, sulfate reducers, and methanogens. Colonies purified from subglacial samples at 4°C appeared to be predominantly psychrophilic. Aerobic chemoheterotrophs were metabolically active in unfrozen basal sediments when they were cultured at 0.3°C in the dark (to simulate nearly in situ conditions), producing
14
CO
2
from radiolabeled sodium acetate with minimal organic amendment (≥38 μM C). In contrast, no activity was observed when samples were cultured at subfreezing temperatures (≤−1.8°C) for 66 days. Electron microscopy of thawed basal ice samples revealed various cell morphologies, including dividing cells. This suggests that the subglacial environment beneath a polythermal glacier provides a viable habitat for life and that microbes may be widespread where the basal ice is temperate and water is present at the base of the glacier and where organic carbon from glacially overridden soils is present. Our observations raise the possibility that in situ microbial production of CO
2
and CH
4
beneath ice masses (e.g., the Northern Hemisphere ice sheets) is an important factor in carbon cycling during glacial periods. Moreover, this terrestrial environment may provide a model for viable habitats for life on Mars, since similar conditions may exist or may have existed in the basal sediments beneath the Martian north polar ice cap.
Ethylene Removal at Low Temperatures under Biofilter and Batch Conditions
Authors: Elsgaard Lars 
Published: July 2002

ABSTRACT

Removal of the plant hormone ethylene (C
2
H
4
) is often required by horticultural storage facilities, which are operated at temperatures below 10°C. The aim of this study was to demonstrate an efficient, biological C
2
H
4
removal under such low-temperature conditions. Peat-soil, acclimated to degradation of C
2
H
4
, was packed in a biofilter (687 cm
3
) and subjected to an airflow (∼73 ml min
−1
) with 2 ppm (μl liter
−1
) C
2
H
4
. The C
2
H
4
removal efficiencies achieved at 20, 10, and 5°C, respectively, were 99.0, 98.8, and 98.4%. This corresponded to C
2
H
4
levels of 0.022 to 0.032 ppm in the biofilter outlet air. At 2°C, the average C
2
H
4
removal efficiency dropped to 83%. The detailed temperature response of C
2
H
4
removal was tested under batch conditions by incubation of 1-g soil samples in a temperature gradient ranging from 0 to 29°C with increments of 1°C. The C
2
H
4
removal rate was highest at 26°C (0.85 μg of C
2
H
4
g [dry weight]
−1
h
−1
), but remained at levels of 0.14 to 0.28 μg of C
2
H
4
g (dry weight)
−1
h
−1
at 0 to 10°C. At 35 to 40°C, the C
2
H
4
removal rate was negligible (0.02 to 0.06 μg of C
2
H
4
g [dry weight]
−1
h
−1
). The
Q
10
(i.e., the ratio of rates 10°C apart) for C
2
H
4
removal was 1.9 for the interval 0 to 10°C. In conclusion, the present results demonstrated microbial C
2
H
4
removal, which proceeded at 0 to 2°C and produced a moderately psychrophilic temperature response.
Transmission to Eels, Portals of Entry, and Putative Reservoirs of
Vibrio vulnificus
Serovar E (Biotype 2)
Authors: Marco-Noales Ester , Milán Miguel , Fouz Belén , Sanjuán Eva , Amaro Carmen 
Published: July 2002

ABSTRACT

Vibrio vulnificus
serovar E (formerly biotype 2) is the etiologic agent that is responsible for the main infectious disease affecting farmed eels. Although the pathogen can theoretically use water as a vehicle for disease transmission, it has not been isolated from tank water during epizootics to date. In this work, the mode of transmission of the disease to healthy eels, the portals of entry of the pathogen into fish, and their putative reservoirs have been investigated by means of laboratory and field experiments. Results of the experiments of direct and indirect host-to-host transmission, patch contact challenges, and oral-anal intubations suggest that water is the prime vehicle for disease transmission and that gills are the main portals of entry into the eel body. The pathogen mixed with food can also come into the fish through the gastrointestinal tract and develop the disease. These conclusions were supported by field data obtained during a natural outbreak in which we were able to isolate this microorganism from tank water for the first time. The examination of some survivors from experimental infections by indirect immunofluorescence and scanning electron microscopy showed that
V. vulnificus
serovar E formed a biofilm-like structure on the eel skin surface. In vitro assays demonstrated that the ability of the pathogen to colonize both hydrophilic and hydrophobic surfaces was inhibited by glucose. The capacity to form biofilms on eel surface could constitute a strategy for surviving between epizootics or outbreaks, and coated survivors could act as reservoirs for the disease.
The Glycogen-Bound Polyphosphate Kinase from
Sulfolobus acidocaldarius
Is Actually a Glycogen Synthase
Authors: Cardona Silvia , Remonsellez Francisco , Guiliani Nicolas , Jerez Carlos A. 
Published: July 2002

ABSTRACT

Inorganic polyphosphate (polyP) is obtained by the polymerization of the terminal phosphate of ATP through the action of the enzyme polyphosphate kinase (PPK). Despite the presence of polyP in every living cell, a gene homologous to that of known PPKs is missing from the currently sequenced genomes of
Eukarya
,
Archaea
, and several bacteria. To further study the metabolism of polyP in
Archaea
, we followed the previously published purification procedure for a glycogen-bound protein of 57 kDa with PPK as well as glycosyl transferase (GT) activities from
Sulfolobus acidocaldarius
(R. Skórko, J. Osipiuk, and K. O. Stetter, J. Bacteriol. 171:5162–5164, 1989). In spite of using recently developed specific enzymatic methods to analyze polyP, we could not reproduce the reported PPK activity for the 57-kDa protein and the polyP presumed to be the product of the reaction most likely corresponded to glycogen-bound ATP under our experimental conditions. Furthermore, no PPK activity was found associated to any of the proteins bound to the glycogen-protein complex. We cloned the gene corresponding to the 57-kDa protein by using reverse genetics and functionally characterized it. The predicted product of the gene did not show similarity to any described PPK but to archaeal and bacterial glycogen synthases instead. In agreement with these results, the recombinant protein showed only GT activity. Interestingly, the GT from
S. acidocaldarius
was phosphorylated in vivo. In conclusion, our results convincingly demonstrate that the glycogen-protein complex of
S. acidocaldarius
does not contain a PPK activity and that what was previously reported as being glycogen-bound PPK is a bacterial enzyme-like thermostable glycogen synthase.
Detection and Quantification of Snow Algae with an Airborne Imaging Spectrometer
Authors: Painter Thomas H. , Duval Brian , Thomas William H. , Mendez Maria , Heintzelman Sara , Dozier Jeff 
Published: July 2002

ABSTRACTWe describe spectral reflectance measurements of snow containing the snow algaChlamydomonas nivalisand a model to retrieve snow algal concentrations from airborne imaging spectrometer data. Because cells ofC. nivalisabsorb at specific wavelengths in regions indicative of carotenoids (astaxanthin esters, lutein, β-carotene) and chlorophyllsaandb, the spectral signature of snow containingC. nivalisis distinct from that of snow without algae. The spectral reflectance of snow containingC. nivalisis separable from that of snow without algae due to carotenoid absorption in the wavelength range from 0.4 to 0.58 μm and chlorophyllaandbabsorption in the wavelength range from 0.6 to 0.7 μm. The integral of the scaled chlorophyllaandbabsorption feature (I0.68) varies with algal concentration (Ca). Using the relationshipCa= 81019.2I0.68+ 845.2, we inverted Airborne Visible Infrared Imaging Spectrometer reflectance data collected in the Tioga Pass region of the Sierra Nevada in California to determine algal concentration. For the 5.5-km2region imaged, the mean algal concentration was 1,306 cells ml−1, the standard deviation was 1,740 cells ml−1, and the coefficient of variation was 1.33. The retrieved spatial distribution was consistent with observations made in the field. From the spatial estimates of algal concentration, we calculated a total imaged algal biomass of 16.55 kg for the 0.495-km2snow-covered area, which gave an areal biomass concentration of 0.033 g/m2.
Integration of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Molecular Cloning for the Identification and Functional Characterization of Mobile
ortho
-Halobenzoate Oxygenase Genes in
Pseudomonas aeruginosa
Strain JB2
Authors: Hickey W. J. , Sabat G. 
Published: July 2002

ABSTRACT

Protein mass spectrometry and molecular cloning techniques were used to identify and characterize mobile
o
-halobenzoate oxygenase genes in
Pseudomonas aeruginosa
strain JB2 and
Pseudomonas huttiensis
strain D1. Proteins induced in strains JB2 and D1 by growth on 2-chlorobenzoate (2-CBa) were extracted from sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and analyzed by matrix-assisted laser desorption ionization–time of flight mass spectrometry. Two bands gave significant matches to OhbB and OhbA, which have been reported to be the α and β subunits, respectively, of an
ortho
-1,2-halobenzoate dioxygenase of
P. aeruginosa
strain 142 (T. V. Tsoi, E. G. Plotnikova, J. R. Cole, W. F. Guerin, M. Bagdasarian, and J. M. Tiedje, Appl. Environ. Microbiol. 65:2151–2162, 1999). PCR and Southern hybridization experiments confirmed that
ohbAB
were present in strain JB2 and were transferred from strain JB2 to strain D1. While the sequences of
ohbA
from strains JB2, D1, and 142 were identical, the sequences of
ohbB
from strains JB2 and D1 were identical to each other but differed slightly from that of strain 142. PCR analyses and Southern hybridization analyses indicated that
ohbAB
were conserved in strains JB2 and D1 and in strain 142 but that the regions adjoining these genes were divergent. Expression of
ohbAB
in
Escherichia coli
resulted in conversion of
o
-chlorobenzoates to the corresponding (chloro)catechols with the following apparent affinity: 2-CBa ≈ 2,5-dichlorobenzoate > 2,3,5-trichlorobenzoate > 2,4-dichlorobenzoate. The activity of OhbAB
JB2
appeared to differ from that reported for OhbAB
142
primarily in that a chlorine in the
para
position posed a greater impediment to catalysis with the former. Hybridization analysis of spontaneous 2-CBa
−
mutants of strains JB2 and D1 verified that
ohbAB
were lost along with the genes, suggesting that all of the genes may be contained in the same mobile element. Strains JB2 and 142 originated from California and Russia, respectively. Thus,
ohbAB
and/or the mobile element on which they are carried may have a global distribution.
pAM401-Based Shuttle Vectors That Enable Overexpression of Promoterless Genes and One-Step Purification of Tag Fusion Proteins Directly from
Enterococcus faecalis
Authors: Fujimoto Shuhei , Ike Yasuyoshi 
Published: July 2002

ABSTRACT

Two novel
Enterococcus faecalis-Escherichia coli
shuttle vectors that utilize the promoter and ribosome binding site of
bacA
on the
E. faecalis
plasmid pPD1 were constructed. The vectors were named pMGS100 and pMGS101. pMGS100 was designed to overexpress cloned genes in
E. coli
and
E. faecalis
and encodes the
bacA
promoter followed by a cloning site and stop codon. pMGS101 was designed for the overexpression and purification of a cloned protein fused to a Strep-tag consisting of 9 amino acids at the carboxyl terminus. The Strep-tag provides the cloned protein with an affinity to immobilized streptavidin that facilitates protein purification. We cloned a promoterless β-galactosidase gene from
E. coli
and cloned the
traA
gene of the
E. faecalis
plasmid pAD1 into the vectors to test gene expression and protein purification, respectively. β-Galactosidase was expressed in
E. coli
and
E. faecalis
at levels of 10
3
and 10 Miller units, respectively. By cloning the pAD1
traA
into pMGS101, the protein could be purified directly from a crude lysate of
E. faecalis
or
E. coli
with an immobilized streptavidin matrix by one-step affinity chromatography. The ability of TraA to bind DNA was demonstrated by the DNA-associated protein tag affinity chromatography method using lysates prepared from both
E. coli
and
E. faecalis
that overexpress TraA. The results demonstrated the usefulness of the vectors for the overexpression and
cis/trans
analysis of regulatory genes, purification and copurification of proteins from
E. faecalis
, DNA binding analysis, determination of translation initiation site, and other applications that require proteins purified from
E. faecalis
.
Comparison of Logistic Regression and Linear Regression in Modeling Percentage Data
Authors: Zhao Lihui , Chen Yuhuan , Schaffner Donald W. 
Published: July 2002

ABSTRACT
Percentage is widely used to describe different results in food microbiology, e.g., probability of microbial growth, percent inactivated, and percent of positive samples. Four sets of percentage data, percent-growth-positive, germination extent, probability for one cell to grow, and maximum fraction of positive tubes, were obtained from our own experiments and the literature. These data were modeled using linear and logistic regression. Five methods were used to compare the goodness of fit of the two models: percentage of predictions closer to observations, range of the differences (predicted value minus observed value), deviation of the model, linear regression between the observed and predicted values, and bias and accuracy factors. Logistic regression was a better predictor of at least 78% of the observations in all four data sets. In all cases, the deviation of logistic models was much smaller. The linear correlation between observations and logistic predictions was always stronger. Validation (accomplished using part of one data set) also demonstrated that the logistic model was more accurate in predicting new data points. Bias and accuracy factors were found to be less informative when evaluating models developed for percentage data, since neither of these indices can compare predictions at zero. Model simplification for the logistic model was demonstrated with one data set. The simplified model was as powerful in making predictions as the full linear model, and it also gave clearer insight in determining the key experimental factors.
Enzymatic Manganese(II) Oxidation by a Marine α-Proteobacterium
Authors: Francis Chris A. , Co Edgie-Mark , Tebo Bradley M. 
Published: July 2002

ABSTRACT

A yellow-pigmented marine bacterium, designated strain SD-21, was isolated from surface sediments of San Diego Bay, San Diego, Calif., based on its ability to oxidize soluble Mn(II) to insoluble Mn(III, IV) oxides. 16S rRNA analysis revealed that this organism was most closely related to members of the genus
Erythrobacter
, aerobic anoxygenic phototrophic bacteria within the α-4 subgroup of the
Proteobacteria
(α-4
Proteobacteria
). SD-21, however, has a number of distinguishing phenotypic features relative to
Erythrobacter
species, including the ability to oxidize Mn(II). During the logarithmic phase of growth, this organism produces Mn(II)-oxidizing factors of ≈250 and 150 kDa that are heat labile and inhibited by both azide and
o
-phenanthroline, suggesting the involvement of a metalloenzyme. Although the expression of the Mn(II) oxidase was not dependent on the presence of Mn(II), higher overall growth yields were reached in cultures incubated with Mn(II) in the culture medium. In addition, the rate of Mn(II) oxidation appeared to be slower in cultures grown in the light. This is the first report of Mn(II) oxidation within the α-4
Proteobacteria
as well as the first Mn(II)-oxidizing proteins identified in a marine gram-negative bacterium.
Detection of
Campylobacter jejuni
and
Campylobacter coli
in Environmental Waters by PCR Enzyme-Linked Immunosorbent Assay
Authors: Sails A. D. , Bolton F. J. , Fox A. J. , Wareing D. R. A. , Greenway D. L. A. 
Published: July 2002

ABSTRACT

A PCR enzyme-linked immunosorbent assay (ELISA) assay was applied to the detection of
Campylobacter jejuni
and
Campylobacter coli
in environmental water samples after enrichment culture. Bacterial cells were concentrated from 69 environmental water samples by using filtration, and the filtrates were cultured in
Campylobacter
blood-free broth. After enrichment culture, DNA was extracted from the samples by using a rapid-boiling method, and the DNA extracts were used as a template in a PCR ELISA assay. A total of 51 samples were positive by either PCR ELISA or culture; of these, 43 were found to be positive by PCR ELISA and 43 were found to be positive by culture. Overall, including positive and negative results, 59 samples were concordant in both methods. Several samples were positive in the PCR ELISA assay but were culture negative; therefore, this assay may be able to detect sublethally damaged or viable nonculturable forms of campylobacters. The method is rapid and sensitive, and it significantly reduces the time needed for the detection of these important pathogens by 2 to 3 days.
Enhanced Accumulation and Changed Monomer Composition in Polyhydroxyalkanoate (PHA) Copolyester by In Vitro Evolution of
Aeromonas caviae
PHA Synthase
Authors: Kichise Tomoyasu , Taguchi Seiichi , Doi Yoshiharu 
Published: July 2002

ABSTRACT

By in vitro evolution experiment, we have first succeeded in acquiring higher active mutants of a synthase that is a key enzyme essential for bacterial synthesis of biodegradable polyester, polyhydroxyalkanoate (PHA).
Aeromonas caviae
FA440 synthase, termed PhaC
Ac
, was chosen as a good target for evolution, since it can synthesize a PHA random copolyester of 3-hydroxybutyrate and 3-hydroxyhexanoate [P(3HB-
co
-3HHx)] that is a tough and flexible material compared to polyhydroxybutyrate (PHB) homopolyester. The in vitro enzyme evolution system consists of PCR-mediated random mutagenesis targeted to a limited region of the

phaC
Ac

gene and screening mutant enzymes with higher activities based on two types of polyester accumulation system by using
Escherichia coli
for the synthesis of PHB (by JM109 strain) (S. Taguchi, A. Maehara, K. Takase, M. Nakahara, H. Nakamura, and Y. Doi, FEMS Microbiol. Lett. 198:65-71, 2001) and of P(3HB-
co
-3HHx) {by LS5218 [
fadR601 atoC
(Con)] strain}. The expression vector for the

phaC
Ac

gene, together with monomer-supplying enzyme genes, was designed to synthesize PHB homopolyester from glucose and P(3HB-
co
-3HHx) copolyester from dodecanoate. Two evolved mutant enzymes, termed E2-50 and T3-11, screened through the evolution system exhibited 56 and 21% increases in activity toward 3HB-coenzyme A, respectively, and consequently led to enhanced accumulation (up to 6.5-fold content) of P(3HB-
co
-3HHx) in the recombinant LS5218 strains. Two single mutations in the mutants, N149S for E2-50 and D171G for T3-11, occurred at positions that are not highly conserved among the PHA synthase family. It should be noted that increases in the 3HHx fraction (up to 16 to 18 mol%) were observed for both mutants compared to the wild type (10 mol%).
Characterization of the Priming Effect by Pituitary Canine Growth Hormone on Canine Polymorphonuclear Neutrophil Granulocyte Function
Authors: Petersen Thomas K. , Smith C. Wayne , Jensen Asger L. 
Published: July 2002

ABSTRACTIn this report, we demonstrate that canine growth hormone (cGH) is capable of priming canine polymorphonuclear neutrophil granulocytes (PMN) in a manner resembling that of human PMN. The cGH influences important functions that are involved in the process of recruitment of PMN, i.e., shape change, chemotaxis, CD11b/CD18 expression, adhesion, and subsequent transendothelial migration. Also, intracellular O2−production was evaluated. We investigated the priming effect by incubating PMN with purified pituitary cGH at various concentrations (10 to 800 μg/liter). The capacity for shape change was significantly (P< 0.05) enhanced, whereas the chemotactic response under agarose was significantly (P< 0.05) reduced. The chemotactic migration in Boyden chambers (10-μm-thick polycarbonate filter; lower surface count technique) was significantly (P< 0.05) enhanced, presumably due to cGH-induced hyperadhesiveness to the lower surface of the filters. The adhesion in albumin-coated microtiter plates and adherence to canine pulmonary fibroblasts were significantly (P< 0.05) increased, and the increased adhesion resulted in a significant (P< 0.01) increase in transendothelial migration using canine jugular vein endothelial cells. The increase in adhesion was associated with a significant increase in CD11b/CD18 expression. Furthermore, intracellular O2−production was significantly enhanced in response to both phorbol myristate acetate (P< 0.01) and opsonized zymosan (P< 0.05). In the absence of a PMN-stimulating agent, cGH did not influence the effector functions investigated except for an increased expression of CD11b/CD18.