bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiac Effects of Echinocandins after Central Venous Administration in Adult Rats
Authors: Koch Christian , Uhle Florian , Wolff Matthias , Arens Christoph , Schulte Astrid , Li Ling , Niemann Bernd , Henrich Michael , Rohrbach Susanne , Weigand Markus A. , Lichtenstern Christoph 
Published: December 2014

ABSTRACT

Echinocandins have become the agents of choice for early and specific antifungal treatment in critically ill patients.
In vitro
studies and clinical case reports revealed a possible impact of echinocandin treatment on cardiac function. The aim of our study was to evaluate echinocandin-induced cardiac failure. Using an
in vivo
rat model, we assessed hemodynamic parameters and time to hemodynamic failure after central venous application (vena jugularis interna) of anidulafungin (low-dose group, 2.5 mg/kg body weight [BW]; high-dose group, 25 mg/kg BW), caspofungin (low-dose group, 0.875 mg/kg BW; high-dose group, 8.75 mg/kg BW), micafungin (low-dose group, 3 mg/kg BW; high-dose group, 30 mg/kg BW), and placebo (0.9% sodium chloride). Left ventricular heart tissue was collected to determine mitochondrial enzyme activity via spectrophotometric measurements. mRNA expression of transcriptional regulators and primary mitochondrial transcripts, mitochondrial DNA (mtDNA) content, and citrate synthase activity were also explored. Animals receiving high-dose anidulafungin or caspofungin showed an immediate decrease in hemodynamic function. All of the subjects in these groups died during the observation period. Every animal in the untreated control group survived (
P
< 0.001). Hemodynamic failure was not noticed in the anidulafungin and caspofungin low-dose groups. Micafungin had no impact on cardiac function. In analyzing mitochondrial enzyme activity and mitochondrial transcripts, we found no association between echinocandin administration and the risk for hemodynamic failure. Further experimental studies are needed to elucidate the underlying mechanisms involved in cardiotoxic echinocandin effects. In addition, randomized controlled clinical trials are needed to explore the clinical impact of echinocandin treatment in critically ill patients.
Ability of Hydroxypropyl Chitosan Nail Lacquer To Protect against Dermatophyte Nail Infection
Authors: Ghannoum M. A. , Long L. , Isham N. , Bulgheroni A. , Setaro M. , Caserini M. , Palmieri R. , Mailland F. 
Published: December 2014

ABSTRACT

The development of a topical agent that would strengthen the nail, improve the natural barrier, and provide better drug penetration to the nail bed is needed. In this study, we examined the effects of a hydroxypropyl chitosan (HPCH)-based nail solution using a bovine hoof model. Following application of the nail solution, changes in the hardness of the hoof samples were measured using the Vickers method. Tensile and flexural strengths were tested by stretching or punching the samples, respectively. The ultrastructure was examined using scanning electron microscopy (SEM), and samples stained with periodic acid-Schiff (PAS) stain were used to determine the fungal penetration depth. The comparators included 40% urea and 70% isopropyl alcohol solutions. The HPCH nail solution increased hoof sample hardness in comparison to the untreated control sample (mean, 22.3 versus 19.4 Vickers pyramid number [HV]). Similarly, the HPCH solution increased the tensile strength (mean, 33.07 versus 28.42 MPa) and flexural strength (mean, 183.79 versus 181.20 MPa) compared to the untreated control. In contrast, the comparators had adverse effects on hardness and strength. SEM showed that the HPCH solution reduced the area of sample crumbling following abrasion compared to the untreated control (7,418 versus 17,843 pixels), and the PAS-stained images showed that the HPCH solution reduced penetration of the dermatophyte hyphae (e.g., penetration by
Trichophyton mentagrophytes
was <25 μm at day 9 versus 275 μm in the untreated control). Unlike chemicals normally used in cosmetic treatments, repeated application of the HPCH nail solution may help prevent the establishment of new or recurring fungal nail infection.
The Mannitol Utilization System of the Marine Bacterium Zobellia galactanivorans
Authors: Groisillier Agnès , Labourel Aurore , Michel Gurvan , Tonon Thierry 
Published: December 2014

ABSTRACT

Mannitol is a polyol that occurs in a wide range of living organisms, where it fulfills different physiological roles. In particular, mannitol can account for as much as 20 to 30% of the dry weight of brown algae and is likely to be an important source of carbon for marine heterotrophic bacteria.
Zobellia galactanivorans
(
Flavobacteriia
) is a model for the study of pathways involved in the degradation of seaweed carbohydrates. Annotation of its genome revealed the presence of genes potentially involved in mannitol catabolism, and we describe here the biochemical characterization of a recombinant mannitol-2-dehydrogenase (M2DH) and a fructokinase (FK). Among the observations, the M2DH of
Z. galactanivorans
was active as a monomer, did not require metal ions for catalysis, and featured a narrow substrate specificity. The FK characterized was active on fructose and mannose in the presence of a monocation, preferentially K
+
. Furthermore, the genes coding for these two proteins were adjacent in the genome and were located directly downstream of three loci likely to encode an ATP binding cassette (ABC) transporter complex, suggesting organization into an operon. Gene expression analysis supported this hypothesis and showed the induction of these five genes after culture of
Z. galactanivorans
in the presence of mannitol as the sole source of carbon. This operon for mannitol catabolism was identified in only 6 genomes of
Flavobacteriaceae
among the 76 publicly available at the time of the analysis. It is not conserved in all
Bacteroidetes
; some species contain a predicted mannitol permease instead of a putative ABC transporter complex upstream of M2DH and FK ortholog genes.
A Chlorogenic Acid Esterase with a Unique Substrate Specificity from Ustilago maydis
Authors: Nieter Annabel , Haase-Aschoff Paul , Kelle Sebastian , Linke Diana , Krings Ulrich , Popper Lutz , Berger Ralf G. 
Published: December 2014

ABSTRACT

An extracellular chlorogenic acid esterase from
Ustilago maydis
(UmChlE) was purified to homogeneity by using three separation steps, including anion-exchange chromatography on a Q Sepharose FF column, preparative isoelectric focusing (IEF), and, finally, a combination of affinity chromatography and hydrophobic interaction chromatography on polyamide. SDS-PAGE analysis suggested a monomeric protein of ∼71 kDa. The purified enzyme showed maximal activity at pH 7.5 and at 37°C and was active over a wide pH range (3.5 to 9.5). Previously described chlorogenic acid esterases exhibited a comparable affinity for chlorogenic acid, but the enzyme from
Ustilago
was also active on typical feruloyl esterase substrates. Kinetic constants for chlorogenic acid, methyl
p
-coumarate, methyl caffeate, and methyl ferulate were as follows:

K
m

values of 19.6 μM, 64.1 μM, 72.5 μM, and 101.8 μM, respectively, and
k
cat
/

K
m

values of 25.83 mM
−1
s
−1
, 7.63 mM
−1
s
−1
, 3.83 mM
−1
s
−1
and 3.75 mM
−1
s
−1
, respectively. UmChlE released ferulic,
p
-coumaric, and caffeic acids from natural substrates such as destarched wheat bran (DSWB) and coffee pulp (CP), confirming activity on complex plant biomass. The full-length gene encoding UmChlE consisted of 1,758 bp, corresponding to a protein of 585 amino acids, and was functionally produced in
Pichia pastoris
GS115. Sequence alignments with annotated chlorogenic acid and feruloyl esterases underlined the uniqueness of this enzyme.
Exploring the Diversity of Listeria monocytogenes Biofilm Architecture by High-Throughput Confocal Laser Scanning Microscopy and the Predominance of the Honeycomb-Like Morphotype
Authors: Guilbaud Morgan , Piveteau Pascal , Desvaux Mickaël , Brisse Sylvain , Briandet Romain 
Published: December 2014

ABSTRACT

Listeria monocytogenes
is involved in food-borne illness with a high mortality rate. The persistence of the pathogen along the food chain can be associated with its ability to form biofilms on inert surfaces. While most of the phenotypes associated with biofilms are related to their spatial organization, most published data comparing biofilm formation by
L. monocytogenes
isolates are based on the quantitative crystal violet assay, which does not give access to structural information. Using a high-throughput confocal-imaging approach, the aim of this work was to decipher the structural diversity of biofilms formed by 96
L. monocytogenes
strains isolated from various environments. Prior to large-scale analysis, an experimental design was created to improve
L. monocytogenes
biofilm formation in microscopic-grade microplates, with special emphasis on the growth medium composition. Microscopic analysis of biofilms formed under the selected conditions by the 96 isolates revealed only weak correlation between the genetic lineages of the isolates and the structural properties of the biofilms. However, a gradient in their geometric descriptors (biovolume, mean thickness, and roughness), ranging from flat multilayers to complex honeycomb-like structures, was shown. The dominant honeycomb-like morphotype was characterized by hollow voids hosting free-swimming cells and localized pockets containing mixtures of dead cells and extracellular DNA (eDNA).
Population Biology of Intestinal Enterococcus Isolates from Hospitalized and Nonhospitalized Individuals in Different Age Groups
Authors: Tedim Ana P. , Ruiz-Garbajosa Patricia , Corander Jukka , Rodríguez Concepción M. , Cantón Rafael , Willems Rob J. , Baquero Fernando , Coque Teresa M. 
Published: December 2014

ABSTRACT

The diversity of enterococcal populations from fecal samples from hospitalized (
n
= 133) and nonhospitalized individuals (
n
= 173) of different age groups (group I, ages 0 to 19 years; group II, ages 20 to 59 years; group III, ages ≥60 years) was analyzed. Enterococci were recovered at similar rates from hospitalized and nonhospitalized persons (77.44% to 79.77%) of all age groups (75.0% to 82.61%).
Enterococcus faecalis
and
Enterococcus faecium
were predominant, although seven other
Enterococcus
species were identified.
E. faecalis
and
E. faecium
(including ampicillin-resistant
E. faecium
) colonization rates in nonhospitalized persons were age independent. For inpatients,
E. faecalis
colonization rates were age independent, but
E. faecium
colonization rates (particularly the rates of ampicillin-resistant
E. faecium
colonization) significantly increased with age. The population structure of
E. faecium
and
E. faecalis
was determined by superimposing goeBURST and Bayesian analysis of the population structure (BAPS). Most
E. faecium
sequence types (STs; 150 isolates belonging to 75 STs) were linked to BAPS groups 1 (22.0%), 2 (31.3%), and 3 (36.7%). A positive association between hospital isolates and BAPS subgroups 2.1a and 3.3a (which included major ampicillin-resistant
E. faecium
human lineages) and between community-based ampicillin-resistant
E. faecium
isolates and BAPS subgroups 1.2 and 3.3b was found. Most
E. faecalis
isolates (130 isolates belonging to 58 STs) were grouped into 3 BAPS groups, BAPS groups 1 (36.9%), 2 (40.0%), and 3 (23.1%), with each one comprising widespread lineages. No positive associations with age or hospitalization were established. The diversity and dynamics of enterococcal populations in the fecal microbiota of healthy humans are largely unexplored, with the available knowledge being fragmented and contradictory. The study offers a novel and comprehensive analysis of enterococcal population landscapes and suggests that
E. faecium
populations from hospitalized patients and from community-based individuals differ, with a predominance of certain clonal lineages, often in association with elderly individuals, occurring in the hospital setting.
Transcriptional Analysis of Deinococcus radiodurans Reveals Novel Small RNAs That Are Differentially Expressed under Ionizing Radiation
Authors: Tsai Chen-Hsun , Liao Rick , Chou Brendan , Contreras Lydia M. 
Published: December 2014

ABSTRACT

Small noncoding RNAs (sRNAs) are posttranscriptional regulators that have been identified in multiple species and shown to play essential roles in responsive mechanisms to environmental stresses. The natural ability of specific bacteria to resist high levels of radiation has been of high interest to mechanistic studies of DNA repair and biomolecular protection.
Deinococcus radiodurans
is a model extremophile for radiation studies that can survive doses of ionizing radiation of >12,000 Gy, 3,000 times higher than for most vertebrates. Few studies have investigated posttranscriptional regulatory mechanisms of this organism that could be relevant in its general gene regulatory patterns. In this study, we identified 199 potential sRNA candidates in
D. radiodurans
by whole-transcriptome deep sequencing analysis and confirmed the expression of 41 sRNAs by Northern blotting and reverse transcriptase PCR (RT-PCR). A total of 8 confirmed sRNAs showed differential expression during recovery after acute ionizing radiation (15 kGy). We have also found and confirmed 7 sRNAs in
Deinococcus geothermalis
, a closely related radioresistant species. The identification of several novel sRNAs in
Deinococcus
bacteria raises important questions about the evolution and nature of global gene regulation in radioresistance.
Accumulation of Reserve Carbohydrate by Rumen Protozoa and Bacteria in Competition for Glucose
Authors: Denton Bethany L. , Diese Leanne E. , Firkins Jeffrey L. , Hackmann Timothy J. 
Published: December 2014

ABSTRACT

The aim of this study was to determine if rumen protozoa could form large amounts of reserve carbohydrate compared to the amounts formed by bacteria when competing for glucose in batch cultures. We separated large protozoa and small bacteria from rumen fluid by filtration and centrifugation, recombined equal protein masses of each group into one mixture, and subsequently harvested (reseparated) these groups at intervals after glucose dosing. This method allowed us to monitor reserve carbohydrate accumulation of protozoa and bacteria individually. When mixtures were dosed with a moderate concentration of glucose (4.62 or 5 mM) (
n
= 2 each), protozoa accumulated large amounts of reserve carbohydrate; 58.7% (standard error of the mean [SEM], 2.2%) glucose carbon was recovered from protozoal reserve carbohydrate at time of peak reserve carbohydrate concentrations. Only 1.7% (SEM, 2.2%) was recovered in bacterial reserve carbohydrate, which was less than that for protozoa (
P
< 0.001). When provided a high concentration of glucose (20 mM) (
n
= 4 each), 24.1% (SEM, 2.2%) of glucose carbon was recovered from protozoal reserve carbohydrate, which was still higher (
P
= 0.001) than the 5.0% (SEM, 2.2%) glucose carbon recovered from bacterial reserve carbohydrate. Our novel competition experiments directly demonstrate that mixed protozoa can sequester sugar away from bacteria by accumulating reserve carbohydrate, giving protozoa a competitive advantage and stabilizing fermentation in the rumen. Similar experiments could be used to investigate the importance of starch sequestration.
Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada
Authors: Chandran Abhirosh , Mazumder Asit 
Published: December 2014

ABSTRACT

Escherichia coli
isolates (
n
= 658) obtained from drinking water intakes of Comox Lake (2011 to 2013) were screened for the following virulence genes (VGs):
stx
1
and
stx
2
(Shiga toxin-producing
E. coli
[STEC]),
eae
and the adherence factor (EAF) gene (enteropathogenic
E. coli
[EPEC]), heat-stable (ST) enterotoxin (variants STh and STp) and heat-labile enterotoxin (LT) genes (enterotoxigenic
E. coli
[ETEC]), and
ipaH
(enteroinvasive
E. coli
[EIEC]). The only genes detected were
eae
and
stx
2
, which were carried by 37.69% (
n
= 248) of the isolates. Only
eae
was harbored by 26.74% (
n
= 176) of the isolates, representing potential atypical EPEC strains, while only
stx
2
was detected in 10.33% (
n
= 68) of the isolates, indicating potential STEC strains. Moreover, four isolates were positive for both the
stx
2
and
eae
genes, representing potential EHEC strains. The prevalence of VGs (
eae
or
stx
2
) was significantly (
P
< 0.0001) higher in the fall season, and multiple genes (
eae
plus
stx
2
) were detected only in fall. Repetitive element palindromic PCR (rep-PCR) fingerprint analysis of 658
E. coli
isolates identified 335 unique fingerprints, with an overall Shannon diversity (
H
′) index of 3.653. Diversity varied among seasons over the years, with relatively higher diversity during fall. Multivariate analysis of variance (MANOVA) revealed that the majority of the fingerprints showed a tendency to cluster according to year, season, and month. Taken together, the results indicated that the diversity and population structure of
E. coli
fluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed. Furthermore, the occurrence of potentially pathogenic
E. coli
strains in the drinking water intakes highlights the risk to human health associated with direct and indirect consumption of untreated surface water.
Comparative Proteome Analysis Reveals Four Novel Polyhydroxybutyrate (PHB) Granule-Associated Proteins in Ralstonia eutropha H16
Authors: Sznajder Anna , Pfeiffer Daniel , Jendrossek Dieter 
Published: December 2014

ABSTRACT

Identification of proteins that were present in a polyhydroxybutyrate (PHB) granule fraction isolated from
Ralstonia eutropha
but absent in the soluble, membrane, and membrane-associated fractions revealed the presence of only 12 polypeptides with PHB-specific locations plus 4 previously known PHB-associated proteins with multiple locations. None of the previously postulated PHB depolymerase isoenzymes (PhaZa2 to PhaZa5, PhaZd1, and PhaZd2) and none of the two known 3-hydroxybutyrate oligomer hydrolases (PhaZb and PhaZc) were significantly present in isolated PHB granules. Four polypeptides were found that had not yet been identified in PHB granules. Three of the novel proteins are putative α/β-hydrolases, and two of those (A0671 and B1632) have a PHB synthase/depolymerase signature. The third novel protein (A0225) is a patatin-like phospholipase, a type of enzyme that has not been described for PHB granules of any PHB-accumulating species. No function has been ascribed to the fourth protein (A2001), but its encoding gene forms an operon with
phaB2
(acetoacetyl-coenzyme A [CoA] reductase) and
phaC2
(PHB synthase), and this is in line with a putative function in PHB metabolism. The localization of the four new proteins at the PHB granule surface was confirmed
in vivo
by fluorescence microscopy of constructed fusion proteins with enhanced yellow fluorescent protein (eYFP). Deletion of A0671 and B1632 had a minor but detectable effect on the PHB mobilization ability in the stationary growth phase of nutrient broth (NB)-gluconate cells, confirming the functional involvement of both proteins in PHB metabolism.
Modulation of Decoding Fidelity by Ribosomal Proteins S4 and S5
Authors: Agarwal Deepali , Kamath Divya , Gregory Steven T. , O'Connor Michael 
Published: December 2014

ABSTRACT

Ribosomal proteins S4 and S5 participate in the decoding and assembly processes on the ribosome and the interaction with specific antibiotic inhibitors of translation. Many of the characterized mutations affecting these proteins decrease the accuracy of translation, leading to a ribosomal-ambiguity phenotype. Structural analyses of ribosomal complexes indicate that the tRNA selection pathway involves a transition between the closed and open conformations of the 30S ribosomal subunit and requires disruption of the interface between the S4 and S5 proteins. In agreement with this observation, several of the mutations that promote miscoding alter residues located at the S4-S5 interface. Here, the
Escherichia coli
rpsD
and
rpsE
genes encoding the S4 and S5 proteins were targeted for mutagenesis and screened for accuracy-altering mutations. While a majority of the 38 mutant proteins recovered decrease the accuracy of translation, error-restrictive mutations were also recovered; only a minority of the mutant proteins affected rRNA processing, ribosome assembly, or interactions with antibiotics. Several of the mutations affect residues at the S4-S5 interface. These include five nonsense mutations that generate C-terminal truncations of S4. These truncations are predicted to destabilize the S4-S5 interface and, consistent with the domain closure model, all have ribosomal-ambiguity phenotypes. A substantial number of the mutations alter distant locations and conceivably affect tRNA selection through indirect effects on the S4-S5 interface or by altering interactions with adjacent ribosomal proteins and 16S rRNA.
A Vascular Model of Tsc1 Deficiency Accelerates Renal Tumor Formation with Accompanying Hemangiosarcomas
Authors: Leech Jarrett D. , Lammers Stephen H.T. , Goldman Sam , Auricchio Neil , Bronson Roderick T. , Kwiatkowski David J. , Sahin Mustafa 
Published: December 2014

Abstract
Tuberous sclerosis complex (TSC) is an autosomal disease caused by inactivating mutations in either of the tumor suppressor genes TSC1 or TSC2. TSC-associated tumor growth is present in multiple tissues and organs including brain, kidney, liver, heart, lungs, and skin. In the kidney, TSC angiomyolipomas have aberrant vascular structures with abnormal endothelial cells, suggesting a role for endothelial mTORC1 function. In the current report, a genetically engineered mouse model (GEMM) with a conditional knockout allele of Tsc1 with a Darpp32-Cre allele displayed accelerated formation of both kidney cystadenomas and paw hemangiosarcomas. All mutant mice developed hemangiosarcomas on multiple paws by 6 weeks of age. By 16 weeks of age, the average mutant hind paw was 4.0 mm in diameter, nearly double the size of control mice. Furthermore, the hemangiosarcomas and kidney cystadenomas were responsive to intraperitoneal rapamycin treatment. Immunoblotting and immunostaining for phospho-S6 (pS6) and phospho-CAD showed that the effect of rapamycin on tumor size was through inhibition of the mTOR signaling pathway. Finally, elevated VEGF mRNA levels were also observed in hemangiosarcoma specimens. Because paw hemangiosarcomas are easily detectable and scorable for size and growth, this novel mouse model enables accelerated in vivo drug testing for therapies of TSC-related tumors.
Implications: These findings provide a strong rationale for simultaneous use of this conditional knockout mouse as an in vivo genetic model while seeking new cancer therapies for TSC-related tumors. Mol Cancer Res; 13(3); 548–55. ©2014 AACR.