bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro
Interaction between Alginate Lyase and Amphotericin B against Aspergillus fumigatus Biofilm Determined by Different Methods
Authors: Bugli Francesca , Posteraro Brunella , Papi Massimiliano , Torelli Riccardo , Maiorana Alessandro , Paroni Sterbini Francesco , Posteraro Patrizia , Sanguinetti Maurizio , De Spirito Marco 
Published: December 2012

ABSTRACT

Aspergillus fumigatus
biofilms represent a problematic clinical entity, especially because of their recalcitrance to antifungal drugs, which poses a number of therapeutic implications for invasive aspergillosis, the most difficult-to-treat
Aspergillus
-related disease. While the antibiofilm activities of amphotericin B (AMB) deoxycholate and its lipid formulations (e.g., liposomal AMB [LAMB]) are well documented, the effectiveness of these drugs in combination with nonantifungal agents is poorly understood. In the present study,
in vitro
interactions between polyene antifungals (AMB and LAMB) and alginate lyase (AlgL), an enzyme degrading the polysaccharides produced as extracellular polymeric substances (EPSs) within the biofilm matrix, against
A. fumigatus
biofilms were evaluated by using the checkerboard microdilution and the time-kill assays. Furthermore, atomic force microscopy (AFM) was used to image and quantify the effects of AlgL-antifungal combinations on biofilm-growing hyphal cells. On the basis of fractional inhibitory concentration index values, synergy was found between both AMB formulations and AlgL, and this finding was also confirmed by the time-kill test. Finally, AFM analysis showed that when
A. fumigatus
biofilms were treated with AlgL or polyene alone, as well as with their combination, both a reduction of hyphal thicknesses and an increase of adhesive forces were observed compared to the findings for untreated controls, probably owing to the different action by the enzyme or the antifungal compounds. Interestingly, marked physical changes were noticed in
A. fumigatus
biofilms exposed to the AlgL-antifungal combinations compared with the physical characteristics detected after exposure to the antifungals alone, indicating that AlgL may enhance the antibiofilm activity of both AMB and LAMB, perhaps by disrupting the hypha-embedding EPSs and thus facilitating the drugs to reach biofilm cells. Taken together, our results suggest that a combination of AlgL and a polyene antifungal may prove to be a new therapeutic strategy for invasive aspergillosis, while reinforcing the EPS as a valuable antibiofilm drug target.
Apoptotic Marker Expression in the Absence of Cell Death in Staurosporine-Treated Leishmania donovani
Authors: Foucher Aude L. , Rachidi Najma , Gharbi Sarah , Blisnick Thierry , Bastin Philippe , Pemberton Iain K. , Späth Gerald F. 
Published: December 2012

ABSTRACT

The protozoan parasite
Leishmania donovani
undergoes several developmental transitions in its insect and vertebrate hosts that are induced by environmental changes. The roles of protein kinases in these adaptive differentiation steps and their potential as targets for antiparasitic intervention are only poorly characterized. Here, we used the generic protein kinase inhibitor staurosporine to gain insight into how interference with phosphotransferase activities affects the viability, growth, and motility of
L. donovani
promastigotes
in vitro
. Unlike the nonkinase drugs miltefosine and amphotericin B, staurosporine strongly reduced parasite biosynthetic activity and had a cytostatic rather than a cytotoxic effect. Despite the induction of a number of classical apoptotic markers, including caspase-like activity and surface binding of annexin V, we determined that, on the basis of cellular integrity, staurosporine did not cause cell death but caused cell cycle arrest and abrogated parasite motility. In contrast, targeted inhibition of the parasite casein kinase 1 (CK1) protein family by use of the CK1-specific inhibitor D4476 resulted in cell death. Thus, pleiotropic inhibition of
L. donovani
protein kinases and possibly other ATP-binding proteins by staurosporine dissociates apoptotic marker expression from cell death, which underscores the relevance of specific rather than broad kinase inhibitors for antiparasitic drug development.
In Vivo
Therapeutic Efficacy of Chloroquine Alone or in Combination with Primaquine against Vivax Malaria in Kolkata, West Bengal, India, and Polymorphism in
pvmdr1
and
pvcrt-o
Genes
Authors: Ganguly Swagata , Saha Pabitra , Guha Subhasish K. , Das Sonali , Bera Dilip K. , Biswas Asit , Kundu Pratip K. , Saha Bibhuti , Ray Krishnangshu , Maji Ardhendu K. 
Published: December 2012

ABSTRACT

Plasmodium vivax
malaria, though benign, has now become a matter of concern due to recent reports of life-threatening severity and development of parasite resistance to different antimalarial drugs. The magnitude of the problem is still undetermined. The present study was undertaken to determine the
in vivo
efficacy of chloroquine (CQ) and chloroquine plus primaquine in
P. vivax
malaria in Kolkata and polymorphisms in the
pvmdr1
and
pvcrt-o
genes. A total of 250 patients with
P. vivax
monoinfection were recruited and randomized into two groups, A and B; treated with chloroquine and chloroquine plus primaquine, respectively; and followed up for 42 days according to the WHO protocol of 2009. Data were analyzed using per-protocol analyses. We assessed polymorphisms of the
pvmdr1 and pvcrt-o
genes by a DNA-sequencing method. Out of the 250 patients recruited, 204 completed a 42-day follow-up period, 101 in group A and 103 in group B. In group A, the non-PCR-corrected efficacy of CQ was 99% (95% confidence interval [CI], 0.944 to 1.00), and in group B, all cases were classified as adequate clinical and parasitological response (ACPR). Day 3 positivity was observed in 11 (5.3%) cases. No specific mutation pattern was recorded in the
pvcrt-o
gene. Eight nonsynonymous mutations were found in the
pvmdr1
gene, three of which were new. The Y976F mutation was not detected in any isolate. Chloroquine, either alone or in combination with primaquine, is still effective against
P. vivax
malaria in the study area. (The study protocol was registered in CTRI [Clinical Trial Registry-India] of the Indian council of Medical Research under registration no. CTRI/2011/09/002031.)
Fosfomycin Synergy
In Vitro
with Amoxicillin, Daptomycin, and Linezolid against Vancomycin-Resistant Enterococcus faecium from Renal Transplant Patients with Infected Urinary Stents
Authors: Descourouez Jillian L. , Jorgenson Margaret R. , Wergin Justine E. , Rose Warren E. 
Published: December 2012

ABSTRACT

Fosfomycin is a potential option for vancomycin-resistant enterococcus (VRE) infections despite limited
in vitro
and clinical data. In this study, 32 VRE isolates from renal transplant patients with urinary stent infections were susceptible to fosfomycin, daptomycin, and linezolid and resistant to amoxicillin, minocycline, and nitrofurantoin based on their MIC
50
s and MIC
90
s. Fosfomycin was bacteriostatic at 0.5 to 16× the MIC (32 to 2,048 μg/ml); synergy occurred when fosfomycin was combined with daptomycin (2.8 to 3.9 log
10
CFU/ml kill;
P
< 0.001) or amoxicillin (2.6 to 3.4;
P
< 0.05). These combinations may be potent options to treat VRE urinary infections pending investigation of clinical efficacy.
Outcomes of Appropriate Empiric Combination versus Monotherapy for Pseudomonas aeruginosa Bacteremia
Authors: Bowers Dana R. , Liew Yi-Xin , Lye David C. , Kwa Andrea L. , Hsu Li-Yang , Tam Vincent H. 
Published: December 2012

ABSTRACT

Pseudomonas aeruginosa
bacteremia is associated with high hospital mortality. Empirical combination therapy is commonly used to increase the likelihood of appropriate therapy, but the benefits of employing >1 active agent have yet to be established. The purpose of this study was to compare outcomes of patients receiving appropriate empirical combination versus monotherapy for
P. aeruginosa
bacteremia. This was a retrospective, multicenter, cohort study of hospitalized adult patients with
P. aeruginosa
bacteremia from 2002 to 2011. The primary endpoint (30-day mortality) was assessed using multivariate logistic regression, adjusting for underlying confounding variables. Secondary endpoints of hospital mortality and time to mortality were assessed by Fisher's exact test and the Cox proportional hazards model, respectively. A total of 384 patients were analyzed. Thirty-day mortality was higher for patients receiving inappropriate therapy than for those receiving appropriate empirical therapy (43.8% versus 21.5%;
P
= 0.03). However, there were no statistical differences in 30-day mortality following appropriate empirical combination versus monotherapy after adjusting for baseline APACHE II scores and lengths of hospital stay prior to the onset of bacteremia (
P
= 0.55). Observed hospital mortality was 36.6% for patients administered combination therapy, compared with 28.7% for monotherapy patients (
P
= 0.17). After adjusting for baseline APACHE II scores, the relationship between time to mortality and combination therapy was not statistically significant (
P
= 0.59). Overall, no significant differences were observed for 30-day mortality, hospital mortality, and time to mortality between combination and monotherapy for
P. aeruginosa
bacteremia. Empirical combination therapy did not appear to offer an additional benefit, as long as the isolate was susceptible to at least one antimicrobial agent.
Evidence for Broad-Spectrum Biofilm Inhibition by the Bacterium Bacillus sp. Strain SW9
Authors: Wu Zhuoying , Ye Chengsong , Guo Feng , Zhang Shenghua , Yu Xin 
Published: December 2012

ABSTRACT

We isolated a
Bacillus
sp. strain that could display broad-spectrum biofilm inhibition. The broad biofilm prevention could be achieved mainly by direct contact between inhibitor and target cells or was accompanied by an interaction with secreted inhibitory compounds. The repression of cell surface fimbria-like appendages of a biofilm producer was also observed; this was considered to contribute to the reduction in mixed biofilms.
Sanitizer Efficacy against Murine Norovirus, a Surrogate for Human Norovirus, on Stainless Steel Surfaces when Using Three Application Methods
Authors: Bolton Stephanie L. , Kotwal Grishma , Harrison Mark A. , Law S. Edward , Harrison Judy A. , Cannon Jennifer L. 
Published: December 2012

ABSTRACT
Human noroviruses are major etiologic agents of epidemic gastroenteritis. Outbreaks are often accompanied by contamination of environmental surfaces, but since these viruses cannot be routinely propagated in laboratory cultures, their response to surface disinfectants is predicted by using surrogates, such as murine norovirus 1 (MNV-1). This study compared the virucidal efficacies of various liquid treatments (three sanitizer liquids, 5% levulinic acid plus 2% SDS [LEV/SDS], 200 ppm chlorine, and an isopropanol-based quaternary ammonium compound [Alpet D2], and two control liquids, sterile tap water and sterile tap water plus 2% SDS) when delivered to MNV-1-inoculated stainless steel surfaces by conventional hydraulic or air-assisted, induction-charged (AAIC) electrostatic spraying or by wiping with impregnated towelettes. For the spray treatments, LEV/SDS proved effective when applied with hydraulic and AAIC electrostatic spraying, providing virus reductions of 2.71 and 1.66 log PFU/ml, respectively. Alpet D2 provided a 2.23-log PFU/ml reduction with hydraulic spraying, outperforming chlorine (1.16-log PFU/ml reduction). Chlorine and LEV/SDS were equally effective as wipes, reducing the viral load by 7.05 log PFU/ml. Controls reduced the viral load by <1 log with spraying applications and by >3 log PFU/ml with wiping. Results indicated that both sanitizer type and application methods should be carefully considered when choosing a surface disinfectant to best prevent and control environmental contamination by noroviruses.
Nutrient Environments Influence Competition among Aspergillus flavus Genotypes
Authors: Mehl Hillary L. , Cotty Peter J. 
Published: December 2012

ABSTRACT

The population dynamics of
Aspergillus flavus
, shaped in part by intraspecific competition, influence the likelihood and severity of crop aflatoxin contamination. Competition for nutrients may be one factor modulating intraspecific interactions, but the influences of specific types and concentrations of nutrients on competition between genotypes of
A. flavus
have not been investigated. Competition between paired
A. flavus
isolates on agar media was affected by varying concentrations of carbon (sucrose or asparagine) and nitrogen (nitrate or asparagine). Cocultivated isolate percentages from conidia and agar-embedded mycelia were quantified by measurements of isolate-specific single-nucleotide polymorphisms with quantitative pyrosequencing. Compositions and concentrations of nutrients influenced conidiation resulting from cocultivation, but the percentages of total conidia from each competing isolate were not predicted by sporulation of isolates grown individually. Success during sporulation did not reflect the outcomes of competition during mycelial growth, and the extents to which isolate percentages from conidia and mycelia differed varied among both isolate pairs and media. Whether varying concentrations of sucrose, nitrate, or asparagine increased, decreased, or had no influence on competitive ability was isolate dependent. Different responses of
A. flavus
isolates to nutrient variability suggest genotypes are adapted to different nutrient environments that have the potential to influence
A. flavus
population structure and the epidemiology of aflatoxin contamination.
Identification of One Novel Candidate Probiotic Lactobacillus plantarum Strain Active against Influenza Virus Infection in Mice by a Large-Scale Screening
Authors: Kechaou Noura , Chain Florian , Gratadoux Jean-Jacques , Blugeon Sébastien , Bertho Nicolas , Chevalier Christophe , Le Goffic Ronan , Courau Stéphanie , Molimard Pascal , Chatel Jean Marc , Langella Philippe , Bermúdez-Humarán Luis G. 
Published: December 2012

ABSTRACT

In this study, we developed a large-scale screening of bacterial strains in order to identify novel candidate probiotics with immunomodulatory properties. For this, 158 strains, including a majority of lactic acid bacteria (LAB), were screened by two different cellular models: tumor necrosis factor alpha (TNF-α)-activated HT-29 cells and peripheral blood mononuclear cells (PBMCs). Different strains responsive to both models (pro- and anti-inflammatory strains) were selected, and their protective effects were tested
in vivo
in a murine model of influenza virus infection. Daily intragastric administrations during 10 days before and 10 days after viral challenge (100 PFU of influenza virus H1N1 strain A Puerto Rico/8/1934 [A/PR8/34]/mouse) of
Lactobacillus plantarum
CNRZ1997, one potentially proinflammatory probiotic strain, led to a significant improvement in mouse health by reducing weight loss, alleviating clinical symptoms, and inhibiting significantly virus proliferation in lungs. In conclusion, in this study, we have combined two cellular models to allow the screening of a large number of LAB for their immunomodulatory properties. Moreover, we identified a novel candidate probiotic strain,
L. plantarum
CNRZ1997, active against influenza virus infection in mice.
Integration of Vibrio vulnificus into Marine Aggregates and Its Subsequent Uptake by Crassostrea virginica Oysters
Authors: Froelich Brett , Ayrapetyan Mesrop , Oliver James D. 
Published: December 2012

ABSTRACT

Marine aggregates are naturally forming conglomerations of larvacean houses, phytoplankton, microbes, and inorganics adhered together by exocellular polymers. In this study, we show
in vitro
that the bacterial pathogen
Vibrio vulnificus
can be concentrated into laboratory-generated aggregates from surrounding water. We further show that environmental (E-genotype) strains exhibit significantly more integration into these aggregates than clinical (C-genotype) strains. Experiments where marine aggregates with attached
V. vulnificus
cells were fed to oysters (
Crassostrea virginica
) resulted in greater uptake of both C and E types than nonaggregated controls. When C- and E-genotype strains were cocultured in competitive experiments, the aggregated E-genotype strains exhibited significantly greater uptake by oyster than the C-genotype strains.
Engineering the Substrate Specificity of a Thermophilic Penicillin Acylase from Thermus thermophilus
Authors: Torres Leticia L. , Cantero Ángel , del Valle Mercedes , Marina Anabel , López-Gallego Fernando , Guisán José M. , Berenguer José , Hidalgo Aurelio 
Published: December 2012

ABSTRACT

A homologue of the
Escherichia coli
penicillin acylase is encoded in the genomes of several thermophiles, including in different
Thermus thermophilus
strains. Although the natural substrate of this enzyme is not known, this acylase shows a marked preference for penicillin K over penicillin G. Three-dimensional models were created in which the catalytic residues and the substrate binding pocket were identified. Through rational redesign, residues were replaced to mimic the aromatic binding site of the
E. coli
penicillin G acylase. A set of enzyme variants containing between one and four amino acid replacements was generated, with altered catalytic properties in the hydrolyses of penicillins K and G. The introduction of a single phenylalanine residue in position α188, α189, or β24 improved the

K
m

for penicillin G between 9- and 12-fold, and the catalytic efficiency of these variants for penicillin G was improved up to 6.6-fold. Structural models, as well as docking analyses, can predict the positioning of penicillins G and K for catalysis and can demonstrate how binding in a productive pose is compromised when more than one bulky phenylalanine residue is introduced into the active site.
dpr
and
sod
in Streptococcus mutans Are Involved in Coexistence with S. sanguinis, and PerR Is Associated with Resistance to H
2
O
2
Authors: Fujishima Kei , Kawada-Matsuo Miki , Oogai Yuichi , Tokuda Masayuki , Torii Mitsuo , Komatsuzawa Hitoshi 
Published: December 2012

ABSTRACT

Large numbers of bacteria coexist in the oral cavity.
Streptococcus sanguinis
, one of the major bacteria in dental plaque, produces hydrogen peroxide (H
2
O
2
), which interferes with the growth of other bacteria.
Streptococcus mutans
, a cariogenic bacterium, can coexist with
S. sanguinis
in dental plaque, but to do so, it needs a means of detoxifying the H
2
O
2
produced by
S. sanguinis
. In this study, we investigated the association of three oxidative stress factors, Dpr, superoxide dismutase (SOD), and AhpCF, with the resistance of
S. sanguinis
to H
2
O
2
. The knockout of
dpr
and
sod
significantly increased susceptibility to H
2
O
2
, while the knockout of
ahpCF
had no apparent effect on susceptibility. In particular,
dpr
inactivation resulted in hypersensitivity to H
2
O
2
. Next, we sought to identify the factor(s) involved in the regulation of these oxidative stress genes and found that PerR negatively regulated
dpr
expression. The knockout of
perR
caused increased
dpr
expression levels, resulting in low-level susceptibility to H
2
O
2
compared with the wild type. Furthermore, we evaluated the roles of
perR
,
dpr
, and
sod
when
S. mutans
was cocultured with
S. sanguinis
. Culturing of the
dpr
or
sod
mutant with
S. sanguinis
showed a significant decrease in the
S. mutans
population ratio compared with the wild type, while the
perR
mutant increased the ratio. Our results suggest that
dpr
and
sod
in
S. mutans
are involved in coexistence with
S. sanguinis
, and PerR is associated with resistance to H
2
O
2
in regulating the expression of Dpr.
Survival of Mycobacterium avium subsp. paratuberculosis in Synthetic Human Gastric Juice and Acidified Porcine Bile
Authors: Dalton J. P. , Hill C. 
Published: December 2012

ABSTRACT

The bactericidal activities of synthetic gastric juice and acidified porcine bile on
Mycobacterium avium
subsp.
paratuberculosis
were assessed using propidium monoazide (PMA)-mediated quantitative reverse transcription-PCR, which allowed rapid relative quantitative analysis of viable
M. avium
subsp.
paratuberculosis
cells.
Transcriptional Changes in the Transition from Vegetative Cells to Asexual Development in the Model Fungus Aspergillus nidulans
Authors: Garzia Aitor , Etxebeste Oier , Rodríguez-Romero Julio , Fischer Reinhard , Espeso Eduardo A. , Ugalde Unai 
Published: December 2012

ABSTRACT

Morphogenesis encompasses programmed changes in gene expression that lead to the development of specialized cell types. In the model fungus
Aspergillus nidulans
, asexual development involves the formation of characteristic cell types, collectively known as the conidiophore. With the aim of determining the transcriptional changes that occur upon induction of asexual development, we have applied massive mRNA sequencing to compare the expression pattern of 19-h-old submerged vegetative cells (hyphae) with that of similar hyphae after exposure to the air for 5 h. We found that the expression of 2,222 (20.3%) of the predicted 10,943
A. nidulans
transcripts was significantly modified after air exposure, 2,035 being downregulated and 187 upregulated. The activation during this transition of genes that belong specifically to the asexual developmental pathway was confirmed. Another remarkable quantitative change occurred in the expression of genes involved in carbon or nitrogen primary metabolism. Genes participating in polar growth or sexual development were transcriptionally repressed, as were those belonging to the HogA/SakA stress response mitogen-activated protein (MAP) kinase pathway. We also identified significant expression changes in several genes purportedly involved in redox balance, transmembrane transport, secondary metabolite production, or transcriptional regulation, mainly binuclear-zinc cluster transcription factors. Genes coding for these four activities were usually grouped in metabolic clusters, which may bring regulatory implications for the induction of asexual development. These results provide a blueprint for further stage-specific gene expression studies during conidiophore development.
Control of Polarized Growth by the Rho Family GTPase Rho4 in Budding Yeast: Requirement of the N-Terminal Extension of Rho4 and Regulation by the Rho GTPase-Activating Protein Bem2
Authors: Gong Ting , Liao Yuan , He Fei , Yang Yang , Yang Dan-Dan , Chen Xiang-Dong , Gao Xiang-Dong 
Published: December 2012

ABSTRACT

In the budding yeast
Saccharomyces cerevisiae
, Rho4 GTPase partially plays a redundant role with Rho3 in the control of polarized growth, as deletion of
RHO4
and
RHO3
together, but not
RHO4
alone, caused lethality and a loss of cell polarity at 30°C. Here, we show that overexpression of the constitutively active
rho4

Q131L

mutant in an
rdi1
Δ strain caused a severe growth defect and generated large, round, unbudded cells, suggesting that an excess of Rho4 activity could block bud emergence. We also generated four temperature-sensitive
rho4-Ts
alleles in a
rho3
Δ
rho4
Δ strain. These mutants showed growth and morphological defects at 37°C. Interestingly, two
rho4-Ts
alleles contain mutations that cause amino acid substitutions in the N-terminal region of Rho4. Rho4 possesses a long N-terminal extension that is unique among the six Rho GTPases in the budding yeast but is common in Rho4 homologs in other yeasts and filamentous fungi. We show that the N-terminal extension plays an important role in Rho4 function since
rho3
Δ
rho4
Δ

61

cells expressing truncated Rho4 lacking amino acids (aa) 1 to 61 exhibited morphological defects at 24°C and a growth defect at 37°C. Furthermore, we show that Rho4 interacts with Bem2, a Rho GTPase-activating protein (RhoGAP) for Cdc42 and Rho1, by yeast two-hybrid, bimolecular fluorescence complementation (BiFC), and glutathione
S
-transferase (GST) pulldown assays. Bem2 specifically interacts with the GTP-bound form of Rho4, and the interaction is mediated by its RhoGAP domain. Overexpression of
BEM2
aggravates the defects of
rho3
Δ
rho4
mutants. These results suggest that Bem2 might be a novel GAP for Rho4.