bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimicrobial Properties of Pyridine-2,6-Dithiocarboxylic Acid, a Metal Chelator Produced by
Pseudomonas
spp
Authors: Sebat J. L. , Paszczynski A. J. , Cortese M. S. , Crawford R. L. 
Published: July 2002

ABSTRACT

Pyridine-2,6-dithiocarboxylic acid (pdtc) is a metal chelator produced by
Pseudomonas
spp. It has been shown to be involved in the biodegradation of carbon tetrachloride; however, little is known about its biological function. In this study, we examined the antimicrobial properties of pdtc and the mechanism of its antibiotic activity. The growth of
Pseudomonas stutzeri
strain KC, a pdtc-producing strain, was significantly enhanced by 32 μM pdtc. All nonpseudomonads and two strains of
P. stutzeri
were sensitive to 16 to 32 μM pdtc. In general, fluorescent pseudomonads were resistant to all concentrations tested. In competition experiments, strain KC demonstrated antagonism toward
Escherichia coli
. This effect was partially alleviated by 100 μM FeCl
3
. Less antagonism was observed in mutant derivatives of strain KC (CTN1 and KC657) which lack the ability to produce pdtc. A competitive advantage was restored to strain CTN1 by cosmid pT31, which restores pdtc production. pT31 also enhanced the pdtc resistance of all pdtc-sensitive strains, indicating that this plasmid contains elements responsible for resistance to pdtc. The antimicrobial effect of pdtc was reduced by the addition of Fe(III), Co(III), and Cu(II) and enhanced by Zn(II). Analyses by mass spectrometry determined that Cu(I):pdtc and Co(III):pdtc
2
form immediately under our experimental conditions. Our results suggest that pdtc is an antagonist and that metal sequestration is the primary mechanism of its antimicrobial activity. It is also possible that Zn(II), if present, may play a role in pdtc toxicity.
Biotransformation of Malachite Green by the FungusCunninghamella elegans
Authors: Cha Chang-Jun , Doerge Daniel R. , Cerniglia Carl E. 
Published: July 2002

ABSTRACTThe filamentous fungusCunninghamella elegansATCC 36112 metabolized the triphenylmethane dye malachite green with a first-order rate constant of 0.029 μmol h−1(mg of cells)−1. Malachite green was enzymatically reduced to leucomalachite green and also converted to N-demethylated and N-oxidized metabolites, including primary and secondary arylamines. Inhibition studies suggested that the cytochrome P450 system mediated both the reduction and the N-demethylation reactions.
Evolution of the Lactic Acid Bacterial Community during Malt Whisky Fermentation: a Polyphasic Study
Authors: van Beek Sylvie , Priest Fergus G. 
Published: July 2002

ABSTRACT

The development of the lactic acid bacterial community in a commercial malt whisky fermentation occurred in three broad phases. Initially, bacteria were inhibited by strong yeast growth. Fluorescence microscopy and environmental scanning electron microscopy revealed, in this early stage, both cocci and rods that were at least partly derived from the wort and yeast but also stemmed from the distillery plant. Denaturing gradient gel electrophoresis (DGGE) of partial 16S rRNA genes and sequence analysis revealed cocci related to
Streptococcus
thermophilus
or
Saccharococcus
thermophilus
,
Lactobacillus
brevis
, and
Lactobacillus
fermentum
. The middle phase began 35 to 40 h after yeast inoculation and was characterized by exponential growth of lactobacilli and residual yeast metabolism.
Lactobacillus
casei
or
Lactobacillus
paracasei
,
L
.
fermentum
, and
Lactobacillus
ferintoshensis
were detected in samples of fermenting wort examined by DGGE during this stage. Bacterial growth was accompanied by the accumulation of acetic and lactic acids and the metabolism of residual maltooligosaccharides. By 70 h, two new PCR bands were detected on DGGE gels, and the associated bacteria were largely responsible for the final phase of the fermentation. The bacteria were phylogenetically related to
Lactobacillus
acidophilus
and
Lactobacillus
delbrueckii
, and strains similar to the former had previously been recovered from malt whisky fermentations in Japan. These were probably obligately homofermentative bacteria, required malt wort for growth, and could not be cultured on normal laboratory media, such as MRS. Their metabolism during the last 20 to 30 h of fermentation was associated with yeast death and autolysis and further accumulation of lactate but no additional acetate.
Phylogenetic Identification and Substrate Uptake Patterns of Sulfate-Reducing Bacteria Inhabiting an Oxic-Anoxic Sewer Biofilm Determined by Combining Microautoradiography and Fluorescent In Situ Hybridization
Authors: Ito Tsukasa , Nielsen Jeppe L. , Okabe Satoshi , Watanabe Yoshimasa , Nielsen Per H. 
Published: July 2002

ABSTRACT

We simultaneously determined the phylogenetic identification and substrate uptake patterns of sulfate-reducing bacteria (SRB) inhabiting a sewer biofilm with oxygen, nitrate, or sulfate as an electron acceptor by combining microautoradiography and fluorescent in situ hybridization (MAR-FISH) with family- and genus-specific 16S rRNA probes. The MAR-FISH analysis revealed that
Desulfobulbus
hybridized with probe 660 was a dominant SRB subgroup in this sewer biofilm, accounting for 23% of the total SRB. Approximately 9 and 27% of
Desulfobulbus
cells detected with probe 660 could take up [
14
C]propionate with oxygen and nitrate, respectively, as an electron acceptor, which might explain the high abundance of this species in various oxic environments. Furthermore, more than 40% of
Desulfobulbus
cells incorporated acetate under anoxic conditions. SRB were also numerically important members of H
2
-utilizing and
14
CO
2
-fixing microbial populations in this sewer biofilm, accounting for roughly 42% of total H
2
-utilizing bacteria hybridized with probe EUB338. A comparative 16S ribosomal DNA analysis revealed that two SRB populations, related to the
Desulfomicrobium hypogeium
and the
Desulfovibrio desulfuricans
MB lineages, were found to be important H
2
utilizers in this biofilm. The substrate uptake characteristics of different phylogenetic SRB subgroups were compared with the characteristics described to date. These results provide further insight into the correlation between the 16S rRNA phylogenetic diversity and the physiological diversity of SRB populations inhabiting sewer biofilms.
Profiles of Airborne Fungi in Buildings and Outdoor Environments in the United States
Authors: Shelton Brian G. , Kirkland Kimberly H. , Flanders W. Dana , Morris George K. 
Published: July 2002

ABSTRACT

We examined 12,026 fungal air samples (9,619 indoor samples and 2,407 outdoor samples) from 1,717 buildings located across the United States; these samples were collected during indoor air quality investigations performed from 1996 to 1998. For all buildings, both indoor and outdoor air samples were collected with an Andersen N6 sampler. The culturable airborne fungal concentrations in indoor air were lower than those in outdoor air. The fungal levels were highest in the fall and summer and lowest in the winter and spring. Geographically, the highest fungal levels were found in the Southwest, Far West, and Southeast. The most common culturable airborne fungi, both indoors and outdoors and in all seasons and regions, were
Cladosporium
,
Penicillium
, nonsporulating fungi, and
Aspergillus. Stachybotrys chartarum
was identified in the indoor air in 6% of the buildings studied and in the outdoor air of 1% of the buildings studied. This study provides industrial hygienists, allergists, and other public health practitioners with comparative information on common culturable airborne fungi in the United States. This is the largest study of airborne indoor and outdoor fungal species and concentrations conducted with a standardized protocol to date.
Quantitative Analysis of Cereulide, the Emetic Toxin of
Bacillus cereus
, Produced under Various Conditions
Authors: Häggblom Max M , Apetroaie Camelia , Andersson Maria A. , Salkinoja-Salonen Mirja S. 
Published: July 2002

ABSTRACT

This paper describes a quantitative and sensitive chemical assay for cereulide, the heat-stable emetic toxin produced by
Bacillus cereus.
The methods previously available for measuring cereulide are bioassays that give a toxicity titer, but not an accurate concentration. The dose of cereulide causing illness in humans is therefore not known, and thus safety limits for cereulide cannot be indicated. We developed a quantitative and sensitive chemical assay for cereulide based on high-performance liquid chromatography (HPLC) connected to ion trap mass spectrometry. This chemical assay and a bioassay based on boar sperm motility inhibition were calibrated with purified cereulide and with valinomycin, a structurally similar cyclic depsipeptide. The boar spermatozoan motility assay and chemical assay gave uniform results over a wide range of cereulide concentrations, ranging from 0.02 to 230 μg ml
−1
. The detection limit for cereulide and valinomycin by HPLC-mass spectrometry was 10 pg per injection. The combined chemical and biological assays were used to define conditions and concentrations of cereulide formation by
B. cereus
strains F4810/72, NC7401, and F5881. Cereulide production commenced at the end of logarithmic growth, but was independent of sporulation. Production of cereulide was enhanced by incubation with shaking compared to static conditions. The three emetic
B. cereus
strains accumulated 80 to 166 μg of cereulide g
−1
(wet weight) when grown on solid medium. Strain NC7401 accumulated up to 25 μg of cereulide ml
−1
in liquid medium at room temperature (21 ± 1°C) in 1 to 3 days, during the stationary growth phase when cell density was 2 × 10
8
to 6 × 10
8
CFU ml
−1
. Cereulide production at temperatures at and below 8°C or at 40°C was minimal.
Species Diversity Improves the Efficiency of Mercury-Reducing Biofilms under Changing Environmental Conditions
Authors: von Canstein Harald , Kelly Sven , Li Ying , Wagner-Döbler Irene 
Published: July 2002

ABSTRACT

Six mercury-resistant environmental proteobacterial isolates and one genetically modified mercury-resistant
Pseudomonas putida
strain were analyzed for physiological traits of adaptive relevance in an environment of packed-bed bioreactors designed for the decontamination of mercury-polluted chlor-alkali wastewater. The strains displayed characteristic differences in each trait (i.e., biofilm formation capability, growth rate in mercury contaminated wastewaters, and mercury reduction efficiency). Subsequently, they were immobilized either as a monoculture or as a mixed culture on porous carrier material in packed-bed bioreactors through which different batches of filter-sterilized industrial chlor-alkali wastewater were pumped. In monospecies bioreactors, the mercury retention efficiency was sensitive to rapidly increasing mercury concentrations in the wastewater. Mixed culture biofilms displayed a high mercury retention efficiency that was not affected by rapid increases in mercury or continuously high mercury concentrations. The dynamic in the community composition of the mixed culture bioreactors was determined by ribosomal intergenic spacer polymorphism analysis. Mercury-mediated selective pressure decreased the number of prevalent strains. Microbial diversity was completely restored after easing of the selective pressure. Microbial diversity provides a reservoir of strains with complementary ecological niches that results in a superior bioreactor performance under changing environmental conditions.
Transmission of Human T-Cell Lymphotropic Virus Type 1 Tax to Rabbits bytax-Only-Positive Human Cells
Authors: Zucker-Franklin Dorothea , Pancake Bette A. , Lalezari Parviz , Khorshidi Manoochehr 
Published: July 2002

ABSTRACTThe human T-cell lymphrotropic virus type 1 (HTLV-1) is causally related to adult T-cell leukemia and lymphoma and the neurodegenerative diseases tropical spastic paraparesis and HTLV-1-associated myelopathy. In the United States the prevalence of infection has been estimated to range from 0.016 to 0.1% on the basis of serologic tests for antibodies to the viral structural proteins. Blood from donors positive for antibodies to HTLV-1 or HTLV-2 is not used for transfusion. However, patients with the cutaneous T-cell lymphoma mycosis fungoides (MF) are HTLV-1 and -2 seronegative yet harbor proviral sequences identical to those that encode the HTLV-1 transactivating and transforming gene product p40taxin their peripheral blood mononuclear cells (PBMCs), and they usually have antibodies to p40tax. Moreover, a study of 250 randomly selected blood donors revealed that approximately 8% of these seronegative individuals also had HTLV-1taxsequences and antibodies to p40tax, while they lacked sequences and antibodies related togag,pol, orenv. Thus, it seemed important to determine whether the “tax-only” state can be transmitted by transfusion. To this end, PBMCs from HTLV-1 and -2 seronegativetax-only-positive MF patients or from healthytax-only-positive blood donors were injected into adult rabbits, an established animal model for HTLV-1 infection. The PBMCs of all injected rabbits becametaxsequence positive. These observations suggest that HTLV-1taxcan be transmitted bytax-only-positive mononuclear cells.
Treponema pallidumSurface Immunofluorescence Assay for Serologic Diagnosis of Syphilis
Authors: Marangoni Antonella , Sambri Vittorio , Storni Elisa , D'Antuono Antonietta , Negosanti Massimo , Cevenini Roberto 
Published: July 2002

ABSTRACTA surface immunofluorescence assay (SIFA) using live spirochetes was analyzed and compared with Western blot (WB), fluorescent treponemal antibody absorption (FTA-ABS), microhemagglutination (MHA-TP), andTreponema pallidumimmobilization (TPI) assays for detecting serum antibodies toT. pallidumin patients with syphilis, in disease controls, and in healthy subjects. SIFA and WB were 99% sensitive (99 of 100 positive specimens) and specific (140 of 140 negative specimens); FTA-ABS showed a sensitivity and a specificity of 90 and 89% (90 of 100 positive and 125 of 140 negative specimens), respectively. MHA-TP showed a sensitivity of 84% (84 of 100 positive specimens) and a specificity of 98.5% (138 of 140 negative specimens). Finally, TPI had a sensitivity of 52% (52 of 100 positive specimens) and a specificity of 100% (140 of 140 negative specimens). TheT. pallidumSIFA was therefore highly specific, showing no equivocal reactivities with control sera, and sensitive. The results suggest the possible use of SIFA as a confirmatory test in the serologic diagnosis of syphilis.
Development of an Enzyme-Linked Immunosorbent Assay for Serotyping
Ureaplasma urealyticum
Strains Using Monoclonal Antibodies
Authors: Echahidi Fedoua , Muyldermans Gaëtan , Lauwers Sabine , Naessens Anne 
Published: July 2002

ABSTRACT

Ureaplasma urealyticum
comprises 14 serotypes. The existing serotyping methods all use polyclonal antibodies. These methods are time-consuming and labor-intensive, and they cannot always be performed on primary isolates; in addition, the results are difficult to interpret. We developed a new enzyme-linked immunosorbent assay (ELISA) method using serotype-specific monoclonal antibodies (MAbs) to enable the serotyping of
U. urealyticum
isolates from primary broth cultures. Each of the 14 serotype reference strains was tested against 14 selected MAbs. Homologous reactions were very strong, while heterologous reactions were negligible. Three cross-reactions were observed: MAb 5 cross-reacted with serotype 2, MAb 14 cross-reacted with serotype 3, and MAb 8 cross-reacted with serotype 13. Despite the cross-reactions observed, all the serotype reference strains of
U. urealyticum
could be identified and differentiated using a combination of MAbs. Reproducibility was analyzed with a fractionated antigenic preparation and with several freshly prepared antigens of the same strain. No significant interrun variation was found with the fractionated antigen, but significant variations in optical density (OD) values were found when freshly prepared antigens were tested. However, the variation in OD values did not influence the overall interpretation of the ELISA: reactions with homologous MAbs were always prominent compared to those of the negative controls. This newly developed ELISA using MAbs seems promising for serotyping of
U. urealyticum
clinical isolates.
Effect of Protein SV-IV on ExperimentalSalmonella entericaSerovar Typhimurium Infection in Mice
Authors: Romano-Carratelli Caterina , Bentivoglio Concetta , Nuzzo Immacolata , Benedetto Nunzia , Buommino Elisabetta , Cozzolino Anna , Cartenì Maria , Morelli Francesco , Costanza Maria Rosaria , Metafora Biancamaria , Metafora Vittoria , Metafora Salvatore 
Published: July 2002

ABSTRACTSeminal vesicle protein IV (SV-IV) is a secretory anti-inflammatory, procoagulant, and immunomodulatory protein produced in large amounts by the seminal vesicle epithelium of the rat under the strict transcriptional control of androgen. In particular, this protein was shown to possess the ability to markedly inhibit in vivo the humoral and cell-mediated immune responses of mice to nonbacterial cellular antigens (sheep erythrocytes and spermatozoa). We report data that demonstrate that in mice treated with SV-IV and infected withSalmonella entericaserovar Typhimurium, SV-IV is able to downregulate some important immunological and biochemical parameters that serovar Typhimurium normally upregulates in these animals. This event did not correlate with a lower bacterial burden but was associated with a markedly increased one (300%). Furthermore, the treatment of mice with SV-IV alone also produced a significant increase in the rate of mortality among serovar Typhimurium-infected animals. The mechanism underlying these phenomena was investigated, and the strong immunosuppression produced by SV-IV in serovar Typhimurium-infected mice was suggested to be the basis for the increased rate of mortality. The SV-IV-mediated immunosuppression was characterized by a decrease in the humoral and cell-mediated immune responses, altered lymphocyte-macrophage interaction, downregulation of cytokine and inducible nitric oxide synthase gene expression, inhibition of macrophage phagocytosis and intracellular killing activities, and absence of apoptosis in the splenocyte population of SV-IV- and serovar Typhimurium-treated mice. The immunosuppressive activity of SV-IV was specific and was not due to aspecific cytotoxic effects. SV-IV-specific receptors (Kd= 10−8M) occurring on the macrophage and lymphocyte plasma membranes may be involved in the molecular mechanism underlying the SV-IV-mediated immunosuppression. Some results obtained by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay also revealed a functional impairment of mitochondria (a decrease in mitochondrial dehydrogenase activity), thus indicating the possible implication of these organelles in the immunosuppressive process.
Activated T Lymphocytes Disappear from Circulation during Endotoxemia in Humans
Authors: Krabbe K. S. , Bruunsgaard H. , Qvist J. , Fonsmark L. , Møller K. , Hansen C. M. , Skinhøj P. , Pedersen B. K. 
Published: July 2002

ABSTRACT

Seventeen volunteers received an intravenous bolus of endotoxin (2 ng/kg of body weight). Endotoxin-induced lymphopenia was constituted mainly by cells with an immature phenotype (CD45RA
+
CD45RO
−
) that were less likely to undergo apoptosis (CD28
+
), whereas cells with the highest rates of disappearance were characterized by an activated phenotype (CD45RA
−
CD45RO
+
) as well as a phenotype linked to apoptosis (CD95
+
CD28
−
). In conclusion, endotoxin-induced lymphopenia reflects the disappearance from the circulation of activated lymphocytes prone to undergo apoptosis.
Endocarditis Due to Rare and Fastidious Bacteria
Authors: Brouqui P. , Raoult D. 
Published: July 2002

SUMMARY
The etiologic diagnosis of infective endocarditis is easily made in the presence of continuous bacteremia with gram-positive cocci. However, the blood culture may contain a bacterium rarely associated with endocarditis, such as Lactobacillus spp., Klebsiella spp., or nontoxigenic Corynebacterium, Salmonella, Gemella, Campylobacter, Aeromonas, Yersinia, Nocardia, Pasteurella, Listeria, or Erysipelothrix spp., that requires further investigation to establish the relationship with endocarditis, or the blood culture may be uninformative despite a supportive clinical evaluation. In the latter case, the etiologic agents are either fastidious extracellular or intracellular bacteria. Fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. need supplemented media, prolonged incubation time, and special culture conditions. Intracellular bacteria such as Coxiella burnetii cannot be isolated routinely. The two most prevalent etiologic agents of culture-negative endocarditis are C. burnetti and Bartonella spp. Their diagnosis is usually carried out serologically. A systemic pathologic examination of excised heart valves including periodic acid-Schiff (PAS) staining and molecular methods has allowed the identification of Whipple's bacillus endocarditis. Pathologic examination of the valve using special staining, such as Warthin-Starry, Gimenez, and PAS, and broad-spectrum PCR should be performed systematically when no etiologic diagnosis is evident through routine laboratory evaluation.
Vaccinia Virus Inhibitors as a Paradigm for the Chemotherapy of Poxvirus Infections
Authors: De Clercq Erik 
Published: July 2002

SUMMARYPoxviruses continue to pose a major threat to human health. Monkeypox is endemic in central Africa, and the discontinuation of the vaccination (with vaccinia virus) has rendered most humans vulnerable to variola virus, the etiologic agent of smallpox, should this virus be used in biological warfare or terrorism. However, a large variety of compounds have been described that are potent inhibitors of vaccinia virus replication and could be expected to be active against other poxviruses as well. These compounds could be grouped in different classes: (i) IMP dehydrogenase inhibitors (e.g., EICAR); (ii) SAH hydrolase inhibitors (e.g., 5′-noraristeromycin, 3-deazaneplanocin A, and various neplanocin A derivatives); (iii) OMP decarboxylase inhibitors (e.g., pyrazofurin) and CTP synthetase inhibitors (e.g., cyclopentenyl cytosine); (iv) thymidylate synthase inhibitors (e.g., 5-substituted 2′-deoxyuridines); (v) nucleoside analogues that are targeted at viral DNA synthesis (e.g., Ara-A); (vi) acyclic nucleoside phosphonates [e.g., (S)-HPMPA and (S)-HPMPC (cidofovir)]; and (vii) polyanionic substances (e.g., polyacrylic acid). All these compounds could be considered potential candidate drugs for the therapy and prophylaxis of poxvirus infections at large. Some of these compounds, in particular polyacrylic acid and cidofovir, were found to generate, on single-dose administration, a long-lasting protective efficacy against vaccinia virus infection in vivo. Cidofovir, which has been approved for the treatment of cytomegalovirus retinitis in immunocompromised patients, was also found to protect mice, again when given as a single dose, against a lethal aerosolized or intranasal cowpox virus challenge. In a biological warfare scenario, it would be advantageous to be able to use a single treatment for an individual exposed to an aerosolized poxvirus. Cidofovir thus holds great promise for treating human smallpox, monkeypox, and other poxvirus infections. Anecdotal experience points to the efficacy of cidofovir in the treatment of the poxvirus infections molluscum contagiosum and orf (ecthyma contagiosum) in immunosuppressed patients.