bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Plasterboard Composition on
Stachybotrys chartarum
Growth and Biological Activity of Spores
Authors: Murtoniemi Timo , Nevalainen Aino , Hirvonen Maija-Riitta 
Published: July 2003

ABSTRACT

The effects of plasterboard composition on the growth and sporulation of
Stachybotrys chartarum
as well as on the inflammatory potential of the spores were studied.
S. chartarum
was grown on 13 modified plasterboards under saturated humidity conditions. The biomass was estimated by measuring the ergosterol content of the
S. chartarum
culture while the spore-induced cytotoxicity and production of nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and interleukin-6 in mouse macrophages was used to illustrate the bioactivity of spores. The ergosterol content of
S. chartarum
correlated with the number of spores collected from plasterboards. The growth and sporulation decreased compared to that of the reference board in those cases where (i) the liner was treated with biocide, (ii) starch was removed from the plasterboard, or (iii) desulfurization gypsum was used in the core. Spores collected from all the plasterboards were toxic to the macrophages. The biocide added to the core did not reduce the growth; in fact, the spores collected from that board evoked the highest cytotoxicity. The conventional additives used in the core had inhibitory effects on growth. Recycled plasterboards used in the core and the board lacking the starch triggered spore-induced TNF-α production in macrophages. In summary, this study shows that the growth of a strain of
S. chartarum
on plasterboard and the subsequent bioactivity of spores were affected by minor changes to the composition of the core or liners, but it could not be totally prevented without resorting to the use of biocides. However, incomplete prevention of microbial growth by biocides even increased the cytotoxic potential of the spores.
The Curing Agent Sodium Nitrite, Used in the Production of Fermented Sausages, Is Less Inhibiting to the Bacteriocin-Producing Meat Starter Culture
Lactobacillus curvatus
LTH 1174 under Anaerobic Conditions
Authors: Verluyten Jurgen , Messens Winy , De Vuyst Luc 
Published: July 2003

ABSTRACT

Curvacin A is a listericidal bacteriocin produced by
Lactobacillus curvatus
LTH 1174, a strain isolated from fermented sausage. The response of this strain to an added curing agent (sodium nitrite) in terms of cell growth and bacteriocin production was investigated in vitro by laboratory fermentations with modified MRS broth. The strain was highly sensitive to nitrite; even a concentration of 10 ppm of curing agent inhibited its growth and both volumetric and specific bacteriocin production. A meat simulation medium containing 5 ppm of sodium nitrite was tested to investigate the influence of the gas phase on the growth and bacteriocin production of
L. curvatus
LTH 1174. Aerating the culture during growth had no effect on biomass formation, but the oxidative stress caused a higher level of specific bacteriocin production and led to a metabolic shift toward acetic acid production. Anaerobic conditions, on the other hand, led to an increased biomass concentration and less growth inhibition. Also, higher maximum volumetric bacteriocin activities and a higher level of specific bacteriocin production were obtained in the presence of sodium nitrite than in fermentations under aerobic conditions or standard conditions of air supply. These results indicate that the inhibitory effect of the curing agent is at least partially masked under anaerobic conditions.
Bacterial Community Dynamics during Production of Registered Designation of Origin Salers Cheese as Evaluated by 16S rRNA Gene Single-Strand Conformation Polymorphism Analysis
Authors: Duthoit Frédérique , Godon Jean-Jacques , Montel Marie-Christine 
Published: July 2003

ABSTRACT

Microbial dynamics during processing and ripening of traditional cheeses such as registered designation of origin Salers cheese, an artisanal cheese produced in France, play an important role in the elaboration of sensory qualities. The aim of the present study was to obtain a picture of the dynamics of the microbial ecosystem of RDO Salers cheese by using culture-independent methods. This included DNA extraction, PCR, and single-strand conformation polymorphism (SSCP) analysis. Bacterial and high-GC% gram-positive bacterial primers were used to amplify V2 or V3 regions of the 16S rRNA gene. SSCP patterns revealed changes during the manufacturing of the cheese. Patterns of the ecosystems of cheeses that were provided by three farmers were also quite different. Cloning and sequencing of the 16S rRNA gene revealed sequences related to lactic acid bacteria (
Lactococcus lactis
,
Streptococcus thermophilus
,
Enterococcus faecium
,
Leuconostoc mesenteroides
,
Leuconostoc pseudomesenteroides
,
Lactobacillus plantarum
, and
Lactobacillus pentosus
), which were predominant during manufacturing and ripening. Bacteria belonging to the high-GC% gram-positive group (essentially corynebacteria) were found by using specific primers. The present molecular approach can effectively describe the ecosystem of artisanal dairy products.
Group A Rotavirus in Sewage Samples from Barcelona and Cairo: Emergence of Unusual Genotypes
Authors: Villena Cristina , El-Senousy Waled Morsy , Abad F. Xavier , Pintó Rosa M. , Bosch Albert 
Published: July 2003

ABSTRACT
The presence of rotavirus strains in sewage samples from Cairo, Egypt (November 1998 to October 1999), and Barcelona, Spain (November 1998 to December 2002), was investigated by using a generic molecular detection method based on amplification of a VP6 gene fragment. Overall, 85.7 and 66.9% of the sewage samples from Cairo and Barcelona, respectively, were positive. Positive samples were characterized further, and VP7 and VP4 genotypes were determined. Although 30% of the positive samples from Cairo were G untypeable, the distribution of G types in the positive samples was 69.6% G1, 13% G3, 8.7% G4, and 8.7% G9. The percentage of untypeable samples was much higher for the Barcelona samples (56.5%), and the distribution in the positive samples was 56.4% G1, 31.5% G3, 6% G9, 4% G2, and 2% G5. When the P types were examined, 26.7% of the positive samples from Cairo were untypeable, and the distribution of types in the positive samples was 53.3% P[8], 30% P[6], and 16.6% P[4]. In Barcelona, 27.2% of the samples were P untypeable, and the frequencies of the types detected were 49.7% P[8], 37.2% P[4], 8.8% P[6], and 4.2% P[9]. The distribution for strains from Cairo was 38.5% P[8]G1, 27% P[6]G1, 11.5% P[4]G1, 11.5% P[8]G3, 7.7% P[6]G4, and 3.8% P[8]G9. Strikingly, equivalent frequencies of common and uncommon strains were observed for Barcelona samples, and the distribution was 38.8% P[8]G1, 30.6% P[4]G1, 11.6% P[8]G3, 6.6% P[4]G3, 5.8% P[6]G1, 1.6% P[6]G3, 1.6% P[9]G1, 0.8% P[4]G2, 0.8% P[6]G9, 0.8% P[8]G9, and 0.8% P[8]G5. Additionally, two P[−]G5 strains were isolated in Barcelona, and the porcine or human origin of these strains was unclear. Rotavirus variability exhibited not only a geographic pattern but also a temporal pattern.
Regio- and Stereoselective Metabolism of 7,12-Dimethylbenz[
a
]anthracene by
Mycobacterium vanbaalenii
PYR-1
Authors: Moody Joanna D. , Fu Peter P. , Freeman James P. , Cerniglia Carl E. 
Published: July 2003

ABSTRACT

The degradation of 7,12-dimethylbenz[
a
]anthracene (DMBA), a carcinogenic polycyclic aromatic hydrocarbon, by cultures of
Mycobacterium vanbaalenii
PYR-1 was studied. When
M. vanbaalenii
PYR-1 was grown in the presence of DMBA for 136 h, high-pressure liquid chromatography (HPLC) analysis showed the presence of four ethyl acetate-extractable compounds and unutilized substrate. Characterization of the metabolites by mass and nuclear magnetic resonance spectrometry indicated initial attack at the C-5 and C-6 positions and on the methyl group attached to C-7 of DMBA. The metabolites were identified as
cis
-5,6-dihydro-5,6-dihydroxy-7,12-dimethylbenz[
a
]anthracene (DMBA
cis
-5,6-dihydrodiol),
trans
-5,6-dihydro-5,6-dihydroxy-7,12-dimethylbenz[
a
]anthracene (DMBA
trans
-5,6-dihydrodiol), and 7-hydroxymethyl-12-methylbenz[
a
]anthracene, suggesting dioxygenation and monooxygenation reactions. Chiral stationary-phase HPLC analysis of the dihydrodiols showed that DMBA
cis
-5,6-dihydrodiol had 95% 5
S
,6
R
and 5% 5
R
,6
S
absolute stereochemistry. On the other hand, the DMBA
trans
-5,6-dihydrodiol was a 100% 5
S
,6
S
enantiomer. A minor photooxidation product, 7,12-epidioxy-7,12-dimethylbenz[
a
]anthracene, was also formed. The results demonstrate that
M. vanbaalenii
PYR-1 is highly regio- and stereoselective in the degradation of DMBA.
Salmonella enterica
Serovar Typhimurium and
Listeria monocytogenes
Acid Tolerance Response Induced by Organic Acids at 20°C: Optimization and Modeling
Authors: Greenacre E. J. , Brocklehurst T. F. , Waspe C. R. , Wilson D. R. , Wilson P. D. G. 
Published: July 2003

ABSTRACT

An acid tolerance response (ATR) has been demonstrated in
Listeria monocytogenes
and
Salmonella enterica
serovar Typhimurium in response to low pH poised (i.e., adapted) with acetic or lactic acids at 20°C and modeled by using dynamic differential equations. The ATR was not immediate or prolonged, and optimization occurred after exposure of
L. monocytogenes
for 3 h at pH 5.5 poised with acetic acid and for 2 h at pH 5.5 poised with lactic acid and after exposure of
S. enterica
serovar Typhimurium for 2 h at pH 5.5 poised with acetic acid and for 3 h at pH 5.5 poised with lactic acid. An objective mechanistic analysis of the acid inactivation data yielded estimates of the duration of the shoulder (
t

s

), the log-linear decline (
k
max
), and the magnitude of a critical component (
C
). The magnitude of
k
max
gave the best agreement with estimates of conditions for optimum ATR induction made from the raw data.
Presence of Viral Genomes in Mineral Water: a Sufficient Condition To Assume Infectious Risk?
Authors: Gassilloud Benoît , Schwartzbrod Louis , Gantzer Christophe 
Published: July 2003

ABSTRACT

Appropriate interpretation of a positive reverse transcription-PCR is an important issue for virus-related health hazard assessment because viral genomes and infectious viruses exhibit different behavior patterns in water. In this context, using
Poliovirus 1
and
Feline calicivirus
f9 as examples of enteric viruses, first we demonstrated that the stability of infectious viruses is greatly affected by the temperature of mineral water (10, 20, and 35°C) and that, in contrast, temperature has little effect on the corresponding genomes. Second, we demonstrated that infectious particles are degraded more rapidly than viral genomes at all temperatures studied. At 35°C,
Poliovirus 1
infectivity was reduced 4 logs after only 19 days, while an equivalent reduction would have taken 75 years (according to the model applied) for the viral genome. Contradictory conclusions can also be drawn concerning the sensitivity of viral serotypes depending on whether the infectious virus or the viral genome is considered. The
Feline calicivirus
f9 genome is more resistant than the
Poliovirus 1
genome, whereas the opposite is true for the corresponding infectious viruses. Thus, we concluded that a positive test for a viral genome in mineral water must be interpreted with utmost caution because of the lack of a correlation between the presence of viral genomes and viral infectivity. Detection of viral genomes may be necessary to identify infectious risk for the human population, but it cannot be considered sufficient.
Reduction of Norwalk Virus, Poliovirus 1, and Bacteriophage MS2 by Ozone Disinfection of Water
Authors: Shin Gwy-Am , Sobsey Mark D. 
Published: July 2003

ABSTRACT

Norwalk virus and other human caliciviruses (noroviruses) are major agents of gastroenteritis, and water is a major route of their transmission. In an effort to control Norwalk virus in drinking water, Norwalk virus reduction by bench-scale ozone disinfection was determined using quantitative reverse transcription (RT)-PCR for virus assays. Two other enteric viruses, poliovirus 1 and coliphage MS2, were included for comparison, and their reductions were assayed by infectivity assays as well as by RT-PCR. Virus reductions by ozone were determined using a dose of 0.37 mg of ozone/liter at pH 7 and 5°C for up to 5 min. Based on two RT-PCR assays, the reductions of Norwalk virus were >3 log
10
within a contact time of 10 s, and these were similar to the reductions of the other two viruses determined by the same assay methods. Also, the virus reductions detected by RT-PCR assays were similar to those detected by infectivity assays, indicating that the RT-PCR assay is a reliable surrogate assay for both culturable and nonculturable viruses disinfected with ozone. Overall, the results of this study indicate that Norwalk virus as well as other enteric viruses can be reduced rapidly and extensively by ozone disinfection and that RT-PCR is a useful surrogate assay for both culturable and nonculturable viruses disinfected with ozone.
Chlorine Inactivation of Adenovirus Type 40 and Feline Calicivirus
Authors: Thurston-Enriquez Jeanette A. , Haas Charles N. , Jacangelo Joseph , Gerba Charles P. 
Published: July 2003

ABSTRACT

Ct
values, the concentration of free chlorine multiplied by time of contact with virus, were determined for free-chlorine inactivation experiments carried out with chloroform-extracted (dispersed) and non-chloroform-extracted (aggregated) feline calicivirus (FCV), adenovirus type 40 (AD40), and polio virus type 1 (PV-1). Experiments were carried out with high and low pH and temperature conditions.
Ct
values were calculated directly from bench-scale free-chlorine inactivation experiments and from application of the efficiency factor Hom model. For each experimental condition,
Ct
values were higher at pH 8 than at pH 6, higher at 5°C than at 15°C, and higher for dispersed AD40 (dAD40) than for dispersed FCV (dFCV). dFCV and dAD40 were more sensitive to free chlorine than dispersed PV-1 (dPV-1).
Ct
s for 2 log inactivation of aggregated FCV (aFCV) and aggregated PV-1 (aPV-1) were 31.0 and 2.8 orders of magnitude higher than those calculated from experiments carried out with dispersed virus.
Ct
s for 2 log inactivation of dFCV and dAD40 in treated groundwater at 15°C were 1.2 and 13.7 times greater than in buffered-demand-free (BDF) water experiments at 5°C.
Ct
values listed in the U.S. Environmental Protection Agency (EPA) Guidance Manual were close to, or lower than,
Ct
values generated for experiments conducted with dispersed and aggregated viruses suspended in BDF water and for dispersed viruses suspended in treated groundwater. Since the state of viruses in water is most likely to be aggregated and associated with organic or inorganic matter, reevaluation of the EPA Guidance Manual
Ct
values is necessary, since they would not be useful for ensuring inactivation of viruses in these states. Under the tested conditions, dAD40, dFCV, aFCV, dPV-1, and aPV-1 particles would be inactivated by commonly used free chlorine concentrations (1 mg/liter) and contact times (60 to 237 min) applied for drinking water treatment in the United States.
Molecular, Serological, and Virulence Characteristics of
Vibrio parahaemolyticus
Isolated from Environmental, Food, and Clinical Sources in North America and Asia
Authors: DePaola Angelo , Ulaszek Jodie , Kaysner Charles A. , Tenge Bradley J. , Nordstrom Jessica L. , Wells Joy , Puhr Nancy , Gendel Steven M. 
Published: July 2003

ABSTRACT

Potential virulence attributes, serotypes, and ribotypes were determined for 178 pathogenic
Vibrio parahaemolyticus
isolates from clinical, environmental, and food sources on the Pacific, Atlantic, and Gulf Coasts of the United States and from clinical sources in Asia. The food and environmental isolates were generally from oysters, and they were defined as being pathogenic by using DNA probes to detect the presence of the thermostable direct hemolysin (
tdh
) gene. The clinical isolates from the United States were generally associated with oyster consumption, and most were obtained from outbreaks in Washington, Texas, and New York. Multiplex PCR was used to confirm the species identification and the presence of
tdh
and to test for the
tdh
-related hemolysin
trh
. Most of the environmental, food, and clinical isolates from the United States were positive for
tdh, trh
, and urease production. Outbreak-associated isolates from Texas, New York, and Asia were predominantly serotype O3:K6 and possessed only
tdh
. A total of 27 serotypes and 28 ribogroups were identified among the isolates, but the patterns of strain distribution differed between the serotypes and ribogroups. All but one of the O3:K6 isolates from Texas were in a different ribogroup from the O3:K6 isolates from New York or Asia. The O3:K6 serotype was not detected in any of the environmental and food isolates from the United States, and none of the food or environmental isolates belonged to any of the three ribogroups that contained all of the O3:K6 and related clinical isolates. The combination of serotyping and ribotyping showed that the Pacific Coast
V. parahaemolyticus
population appeared to be distinct from that of either the Atlantic Coast or Gulf Coast. The fact that certain serotypes and ribotypes contained both clinical and environmental isolates while many others contained only environmental isolates implies that certain serotypes or ribotypes are more relevant for human disease.
Analysis of
Vibrio vulnificus
from Market Oysters and Septicemia Cases for Virulence Markers
Authors: DePaola Angelo , Nordstrom Jessica L. , Dalsgaard Anders , Forslund Anita , Oliver James , Bates Tonya , Bourdage Keri L. , Gulig Paul A. 
Published: July 2003

ABSTRACT

Representative encapsulated strains of
Vibrio vulnificus
from market oysters and oyster-associated primary septicemia cases (25 isolates each) were tested in a blinded fashion for potential virulence markers that may distinguish strains from these two sources. These isolates were analyzed for plasmid content, for the presence of a 460-bp amplicon by randomly amplified polymorphic DNA PCR, and for virulence in subcutaneously (s.c.) inoculated, iron-dextran-treated mice. Similar percentages of market oyster and clinical isolates possessed detectable plasmids (24 and 36%, respectively), produced the 460-bp amplicon (45 and 50%, respectively), and were judged to be virulent in the mouse s.c. inoculation-iron-dextran model (88% for each). Therefore, it appears that nearly all
V. vulnificus
strains in oysters are virulent and that genetic tests for plasmids and specific PCR size amplicons cannot distinguish between fully virulent and less virulent strains or between clinical and environmental isolates. The inability of these methods to distinguish food and clinical
V. vulnificus
isolates demonstrates the need for alternative subtyping approaches and virulence assays.
Adaptation ofSaccharomyces cerevisiaeto the Herbicide 2,4-Dichlorophenoxyacetic Acid, Mediated by Msn2p- and Msn4p-Regulated Genes: Important Role ofSPI1
Authors: Simões T. , Teixeira M. C. , Fernandes A. R. , Sá-Correia Isabel 
Published: July 2003

ABSTRACTThe possible roles of 13 Msn2p- and Msn4p-regulated genes in the adaptation ofSaccharomyces cerevisiaeto the herbicide 2,4-d-dichlorophenoxyacetic acid (2,4-D) were examined. Single deletion of genes involved in defense against oxidizing agents (CTT1,GRX1, andGRX2/TTR1) or encoding chaperones of the HSP70 family (SSA1,SSA4, andSSE2) showed a slight effect. A more significant role was observed for the heat shock genesHSP78,HSP26,HSP104,HSP12, andHSP42, most of which encode molecular chaperones. However, theSPI1gene, encoding a member of the glycosylphosphatidylinositol-anchored cell wall protein family, emerged as the major determinant of 2,4-D resistance.SPI1expression reduced the loss of viability of an unadapted yeast population suddenly exposed to the herbicide, allowing earlier growth resumption. Significantly, yeast adaptation to 2,4-D involves the rapid and transient Msn2p- and Msn4p-mediated activation (fivefold) of SPI1transcription.SPI1mRNA levels were reduced to values slightly above those in unstressed cells when the adapted population started duplication in the presence of 2,4-D. SinceSPI1deletion leads to the higher β-1,3-glucanase sensitivity of 2,4-D-stressed cells, it was hypothesized that adaptation may involve an Spi1p-mediated increase in the diffusional restriction of the liposoluble acid form of the herbicide across the cell envelope. Such a cell response would avoid a futile cycle due to acid reentry into the cell counteracting the active export of the anionic form, presumably through an inducible plasma membrane transporter(s). Consistent with this concept, the concentration of14C-labeled 2,4-D in 2,4-D-energized adapted Δspi1mutant cells and the consequent intracellular acidification are higher than in wild-type cells.
Production of 6-Phenylacetylene Picolinic Acid from Diphenylacetylene by a Toluene-Degrading
Acinetobacter
Strain
Authors: Spain Jim C. , Nishino Shirley F. , Witholt Bernard , Tan Loon-Seng , Duetz Wouter A. 
Published: July 2003

ABSTRACT

Several strategies for using enzymes to catalyze reactions leading to the synthesis of relatively simple substituted picolinic acids have been described. The goal of the work described here was to synthesize a more complex molecule, 6-phenylacetylene picolinic acid [6-(2-phenylethynyl)pyridine-2-carboxylic acid], for use as a potential endcapping agent for aerospace polymers. We screened 139 toluene-degrading strains that use a variety of catabolic pathways for the ability to catalyze oxidative transformation of diphenylacetylene.
Acinetobacter
sp. strain F4 catalyzed the overall conversion of diphenylacetylene to a yellow metabolite, which was identified as a putative
meta
ring fission product (2-hydroxy-8-phenyl-6-oxoocta-2,4-dien-7-ynoic acid [RFP]). The activity could be sustained by addition of toluene at a flow rate determined empirically so that the transformations were sustained in spite of the fact that toluene is a competitive inhibitor of the enzymes. The overall rate of transformation was limited by the instability of RFP. The RFP was chemically converted to 6-phenylacetylene picolinic acid by treatment with ammonium hydroxide. The results show the potential for using the normal growth substrate to provide energy and to maintain induction of the enzymes involved in biotransformation during preliminary stages of biocatalyst development.