bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of a Pollen Trap Design To Capture Airborne Conidia of Entomophaga maimaiga and Detection of Conidia by Quantitative PCR
Authors: Bittner Tonya D. , Hajek Ann E. , Liebhold Andrew M. , Thistle Harold 
Published: June 2017

ABSTRACT

The goal of this study was to develop effective and practical field sampling methods for quantification of aerial deposition of airborne conidia of
Entomophaga maimaiga
over space and time. This important fungal pathogen is a major cause of larval death in invasive gypsy moth (
Lymantria dispar
) populations in the United States. Airborne conidia of this pathogen are relatively large (similar in size to pollen), with unusual characteristics, and require specialized methods for collection and quantification. Initially, dry sampling (settling of spores from the air onto a dry surface) was used to confirm the detectability of
E. maimaiga
at field sites with
L. dispar
deaths caused by
E. maimaiga
, using quantitative PCR (qPCR) methods. We then measured the signal degradation of conidial DNA on dry surfaces under field conditions, ultimately rejecting dry sampling as a reliable method due to rapid DNA degradation. We modified a chamber-style trap commonly used in palynology to capture settling spores in buffer. We tested this wet-trapping method in a large-scale (137-km) spore-trapping survey across gypsy moth outbreak regions in Pennsylvania undergoing epizootics, in the summer of 2016. Using 4-day collection periods during the period of late instar and pupal development, we detected variable amounts of target DNA settling from the air. The amounts declined over the season and with distance from the nearest defoliated area, indicating airborne spore dispersal from outbreak areas.

IMPORTANCE
We report on a method for trapping and quantifying airborne spores of
Entomophaga maimaiga
, an important fungal pathogen affecting gypsy moth (
Lymantria dispar
) populations. This method can be used to track dispersal of
E. maimaiga
from epizootic areas and ultimately to provide critical understanding of the spatial dynamics of gypsy moth-pathogen interactions.
Quantifying Vibrio cholerae Enterotoxicity in a Zebrafish Infection Model
Authors: Mitchell Kristie C. , Breen Paul , Britton Sarah , Neely Melody N. , Withey Jeffrey H. 
Published: June 2017

ABSTRACT

Vibrio cholerae
is the etiological agent of cholera, an acute intestinal infection in humans characterized by voluminous watery diarrhea. Cholera is spread through ingestion of contaminated food or water, primarily in developing countries that lack the proper infrastructure for proper water and sewage treatment.
Vibrio cholerae
is an aquatic bacterium that inhabits coastal and estuarine areas, and it is known to have several environmental reservoirs, including fish. Our laboratory has recently described the use of the zebrafish as a new animal model for the study of
V. cholerae
intestinal colonization, pathogenesis, and transmission. As early as 6 h after exposure to
V. cholerae
, zebrafish develop diarrhea. Prior work in our laboratory has shown that this is not due to the action of cholera toxin. We hypothesize that accessory toxins produced by
V. cholerae
are the cause of diarrhea in infected zebrafish. In order to assess the effects of accessory toxins in the zebrafish, it was necessary to develop a method of quantifying diarrheal volume as a measure of pathogenesis. Here, we have adapted cell density, protein, and mucin assays, along with enumeration of
V. cholerae
in the zebrafish intestinal tract and in the infection water, to achieve this goal. Combined, these assays should help us determine which toxins have the greatest diarrheagenic effect in fish and, consequently, which toxins may play a role in environmental transmission.

IMPORTANCE
Identification of the accessory toxins that cause diarrhea in zebrafish can help us understand more about the role of fish in the wild as aquatic reservoirs for
V. cholerae
. It is plausible that accessory toxins can act to prolong colonization and subsequent shedding of
V. cholerae
back into the environment, thus perpetuating and facilitating transmission during an outbreak. It is also possible that accessory toxins help to maintain low levels of intestinal colonization in fish, giving
V. cholerae
an advantage when environmental conditions are not optimal for survival in the water. Studies such as this one are critical because fish could be an overlooked source of cholera transmission in the environment.
Structures, Compositions, and Activities of Live Shewanella Biofilms Formed on Graphite Electrodes in Electrochemical Flow Cells
Authors: Kitayama Miho , Koga Ryota , Kasai Takuya , Kouzuma Atsushi , Watanabe Kazuya 
Published: June 2017

ABSTRACT

An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with
Shewanella oneidensis
MR-1 expressing an anaerobic fluorescent protein, and biofilm formation on the WE was observed over time during current generation at WE potentials of +0.4 and 0 V (versus standard hydrogen electrodes), under electrolyte-flow conditions. Electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.4-V biofilm. Microscopic analyses revealed that, in contrast to aerobic biofilms, current-generating biofilm (at +0.4 V) was thin and flat (∼10 μm in thickness), and cells were evenly and densely distributed in the biofilm. In contrast, cells were unevenly distributed in biofilm formed at 0 V.
In situ
fluorescence staining and biofilm recovery experiments showed that the amounts of extracellular polysaccharides (EPSs) in the +0.4-V biofilm were much smaller than those in the aerobic and 0-V biofilms, suggesting that
Shewanella
cells suppress the production of EPSs at +0.4 V under flow conditions. We suggest that
Shewanella
cells perceive electrode potentials and modulate the structure and composition of biofilms to efficiently transfer electrons to electrodes.

IMPORTANCE
A promising application of microbial fuel cells (MFCs) is to save energy in wastewater treatment. Since current is generated in these MFCs by biofilm microbes under horizontal flows of wastewater, it is important to understand the mechanisms for biofilm formation and current generation under water-flow conditions. Although massive work has been done to analyze the molecular mechanisms for current generation by model exoelectrogenic bacteria, such as
Shewanella oneidensis
, limited information is available regarding the formation of current-generating biofilms over time under water-flow conditions. The present study developed electrochemical flow cells and used them to examine the electrochemical and structural features of current-generating biofilms under water-flow conditions. We show unique features of mature biofilms actively generating current, creating opportunities to search for as-yet-undiscovered current-generating mechanisms in
Shewanella
biofilms. Furthermore, information provided in the present study is useful for researchers attempting to develop anode architectures suitable for wastewater treatment MFCs.
Metabolic Engineering of Actinobacillus succinogenes Provides Insights into Succinic Acid Biosynthesis
Authors: Guarnieri Michael T. , Chou Yat-Chen , Salvachúa Davinia , Mohagheghi Ali , St. John Peter C. , Peterson Darren J. , Bomble Yannick J. , Beckham Gregg T. 
Published: June 2017

ABSTRACT

Actinobacillus succinogenes
, a Gram-negative facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition,
A. succinogenes
is capnophilic, incorporating CO
2
into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO
2
to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in
A. succinogenes
, enabling examination of SA flux determinants via knockout of the primary competing pathways—namely, acetate and formate production—and overexpression of the key enzymes in the reductive branch of the TCA cycle leading to SA. Batch fermentation experiments with the wild-type and engineered strains using pentose-rich sugar streams demonstrate that the overexpression of the SA biosynthetic machinery (in particular, the enzyme malate dehydrogenase) enhances flux to SA. Additionally, removal of competitive carbon pathways leads to higher-purity SA but also triggers the generation of by-products not previously described from this organism (e.g., lactic acid). The resultant engineered strains also lend insight into energetic and redox balance and elucidate mechanisms governing organic acid biosynthesis in this important natural SA-producing microbe.

IMPORTANCE
Succinic acid production from lignocellulosic residues is a potential route for enhancing the economic feasibility of modern biorefineries. Here, we employ facile genetic tools to systematically manipulate competing acid production pathways and overexpress the succinic acid-producing machinery in
Actinobacillus succinogenes
. Furthermore, the resulting strains are evaluated via fermentation on relevant pentose-rich sugar streams representative of those from corn stover. Overall, this work demonstrates genetic modifications that can lead to succinic acid production improvements and identifies key flux determinants and new bottlenecks and energetic needs when removing by-product pathways in
A. succinogenes
metabolism.
Rapid, High-Throughput Identification of Anthrax-Causing and Emetic Bacillus cereus Group Genome Assemblies via BTyper, a Computational Tool for Virulence-Based Classification of Bacillus cereus Group Isolates by Using Nucleotide Sequencing Data
Authors: Carroll Laura M. , Kovac Jasna , Miller Rachel A. , Wiedmann Martin 
Published: June 2017

ABSTRACT

The
Bacillus cereus
group comprises nine species, several of which are pathogenic. Differentiating between isolates that may cause disease and those that do not is a matter of public health and economic importance, but it can be particularly challenging due to the high genomic similarity within the group. To this end, we have developed BTyper, a computational tool that employs a combination of (i) virulence gene-based typing, (ii) multilocus sequence typing (MLST), (iii)
panC
clade typing, and (iv)
rpoB
allelic typing to rapidly classify
B. cereus
group isolates using nucleotide sequencing data. BTyper was applied to a set of 662
B. cereus
group genome assemblies to (i) identify anthrax-associated genes in non-
B. anthracis
members of the
B. cereus
group, and (ii) identify assemblies from
B. cereus
group strains with emetic potential. With BTyper, the anthrax toxin genes
cya
,
lef
, and
pagA
were detected in 8 genomes classified by the NCBI as
B. cereus
that clustered into two distinct groups using
k
-medoids clustering, while either the
B. anthracis
poly-γ-
d
-glutamate capsule biosynthesis genes
capABCDE
or the hyaluronic acid capsule
hasA
gene was detected in an additional 16 assemblies classified as either
B. cereus
or
Bacillus thuringiensis
isolated from clinical, environmental, and food sources. The emetic toxin genes
cesABCD
were detected in 24 assemblies belonging to
panC
clades III and VI that had been isolated from food, clinical, and environmental settings. The command line version of BTyper is available at
https://github.com/lmc297/BTyper
. In addition, BMiner, a companion application for analyzing multiple BTyper output files in aggregate, can be found at
https://github.com/lmc297/BMiner
.

IMPORTANCE
Bacillus cereus
is a foodborne pathogen that is estimated to cause tens of thousands of illnesses each year in the United States alone. Even with molecular methods, it can be difficult to distinguish nonpathogenic
B. cereus
group isolates from their pathogenic counterparts, including the human pathogen
Bacillus anthracis
, which is responsible for anthrax, as well as the insect pathogen
B. thuringiensis
. By using the variety of typing schemes employed by BTyper, users can rapidly classify, characterize, and assess the virulence potential of any isolate using its nucleotide sequencing data.
Therapeutic potential of omega-3 fatty acids supplementation in a mouse model of dry macular degeneration
Authors: Prokopiou Ekatherine , Kolovos Panagiotis , Kalogerou Maria , Neokleous Anastasia , Papagregoriou Gregory , Deltas Constantinos , Malas Stavros , Georgiou Tassos 
Published: June 2017

PurposeTo evaluate the therapeutic effects of omega-3 (ω-3) and omega-6 (ω-6) fatty acids in the CCL2−/−model of dry age-related macular degeneration (AMD). The blood level of eicosapentaenoic acid (EPA) and arachidonic acid (AA) served to adjust the treatment dosage (AA/EPA=1–1.5).MethodsNine-month-old animals were allocated to different groups: (A) C57BL/6 untreated , (B) CCL2−/−untreated, (C) CCL2−/−treated with ω-3+ω-6, and (D) CCL2−/−treated with ω-3. Treatment was daily administered by gavage for 3 months. Fatty acids analysis was performed and retinas were histologically examined. Three-month-old wild type mice were used for comparison purposes. Real-time PCR and Western blot were performed for retinal inflammatory mediators.ResultsIncreased EPA and decreased AA levels were observed in both blood and retinas in the treatment groups. The outer nuclear layer thickness was increased in groups C (45.0±3.9 µm) and D (62.8±4.9 µm), compared with groups B (65.6±3.0 µm) and A (71.1±4.2 µm), and in younger mice, it was 98.0±3.9 µm. A decrease in NF-κB expression was noted in the treatment groups. Interleukin (IL) 18 protein levels demonstrated a significant reduction in the ω-3-treated group only.ConclusionSupplementation with ω-3+ω-6 or ω-3 alone (AA/EPA=1–1.5) suggests a protective mechanism in the CCL2−/−animal model of dry AMD, with a more beneficial effect when ω-3 are used alone. Our findings indicated that inflammation is not the only determining factor; perhaps a regenerative process might be involved following administration of ω-3 fatty acids.
A-type K+ channels contribute to the prorenin increase of firing activity in hypothalamic vasopressin neurosecretory neurons
Authors: Pitra Soledad , Stern Javier E. 
Published: June 2017

Recent studies have supported an important contribution of prorenin (PR) and its receptor (PRR) to the regulation of hypothalamic, sympathetic, and neurosecretory outflows to the cardiovascular system, including systemic release of vasopressin (VP), both under physiological and cardiovascular disease conditions. Still, the identification of precise cellular mechanisms and neuronal/molecular targets remain unknown. We have recently shown that PRR is expressed in VP neurons and that their activation increases neuronal activity. However, the underlying ionic channel mechanisms are undefined. Here, we performed patch-clamp electrophysiology from identified VP neurons in acute hypothalamic slices obtained from enhanced green fluorescent protein-VP transgenic rats. Voltage-clamp recordings showed that PR inhibited the magnitude of A-type K+ current ( IA; ~50% at −25 mV), a subthreshold voltage-dependent current that restrains VP firing activity. PR also increased the inactivation rate of IA and shifted the steady-state voltage-dependent inactivation function toward more hyperpolarized membrane potential (~7 mV shift), thus resulting in less channel availability to be activated at any given membrane potential. PR also inhibited a sustained component of IA (“window” current). PR-mediated changes in action potential waveform and increased firing activity were occluded when IA was blocked by 4-aminopyridine. Finally, PR failed to increase superoxide production within the supraoptic nucleus/paraventricular nucleus, and PR excitatory effects persisted in slices treated with the SOD mimetic tempol. Taken together, these experiments indicated that PR excitatory effects on vasopressin neurons involve inhibition of IA, due, in part, to increases in its voltage-dependent inactivation properties. Moreover, our results indicate that PR effects did not involve an increase in oxidative stress. NEW & NOTEWORTHY Here, we demonstrate that prorenin/the prorenin receptor is an important signaling unit for the regulation of vasopressin firing activity and, thus, systemic hormonal release. We identified A-type K+ channels as key molecular targets mediating prorenin stimulation of vasopressin neuronal activity, thus standing as a potential therapeutic target for neurohumoral activation in cardiovascular disease.
Significant role of the cardiopostural interaction in blood pressure regulation during standing
Authors: Xu Da , Verma Ajay K. , Garg Amanmeet , Bruner Michelle , Fazel-Rezai Reza , Blaber Andrew P. , Tavakolian Kouhyar 
Published: June 2017

Cardiovascular and postural control systems have been studied independently despite the increasing evidence showing the importance of cardiopostural interaction in blood pressure regulation. In this study, we aimed to assess the role of the cardiopostural interaction in relation to cardiac baroreflex in blood pressure regulation under orthostatic stress before and after mild exercise. Physiological variables representing cardiovascular control (heart rate and systolic blood pressure), lower limb muscle activation (electromyography), and postural sway (center of pressure derived from force and moment data during sway) were measured from 17 healthy participants (25 ± 2 yr, 9 men and 8 women) during a sit-to-stand test before and after submaximal exercise. The cardiopostural control (characterized by baroreflex-mediated muscle-pump effect in response to blood pressure changes, i.e., muscle-pump baroreflex) was assessed using wavelet transform coherence and causality analyses in relation to the baroreflex control of heart rate. Significant cardiopostural blood pressure control was evident counting for almost half of the interaction time with blood pressure changes that observed in the cardiac baroreflex (36.6–72.5% preexercise and 34.7–53.9% postexercise). Thus, cardiopostural input to blood pressure regulation should be considered when investigating orthostatic intolerance. A reduction of both cardiac and muscle-pump baroreflexes in blood pressure regulation was observed postexercise and was likely due to the absence of excessive venous pooling and a less stressed system after mild exercise. With further studies using more effective protocols evoking venous pooling and muscle-pump activity, the cardiopostural interaction could improve our understanding of the autonomic control system and ultimately lead to a more accurate diagnosis of cardiopostural dysfunctions.NEW & NOTEWORTHY We examined the interaction between cardiovascular and postural control systems during standing before and after mild exercise. Significant cardiopostural input to blood pressure regulation was shown, suggesting the importance of cardiopostural integration when investigating orthostatic hypotension. In addition, we observed a reduction of baroreflex-mediated blood pressure regulation after exercise.
A Genome-Wide CRISPR Screen Identifies Genes Critical for Resistance to FLT3 Inhibitor AC220
Authors: Hou Panpan , Wu Chao , Wang Yuchen , Qi Rui , Bhavanasi Dheeraj , Zuo Zhixiang , Dos Santos Cedric , Chen Shuliang , Chen Yu , Zheng Hong , Wang Hong , Perl Alexander , Guo Deyin , Huang Jian 
Published: June 2017

Abstract
Acute myeloid leukemia (AML) is a malignant hematopoietic disease and the most common type of acute leukemia in adults. The mechanisms underlying drug resistance in AML are poorly understood. Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are the most common molecular abnormality in AML. Quizartinib (AC220) is a potent and selective second-generation inhibitor of FLT3. It is in clinical trials for the treatment of relapsed or refractory FLT3-ITD–positive and –negative AML patients and as maintenance therapy. To understand the mechanisms of drug resistance to AC220, we undertook an unbiased approach with a novel CRISPR-pooled library to screen new genes whose loss of function confers resistance to AC220. We identified SPRY3, an intracellular inhibitor of FGF signaling, and GSK3, a canonical Wnt signaling antagonist, and demonstrated reactivation of downstream FGF/Ras/ERK and Wnt signaling as major mechanisms of resistance to AC220. We confirmed these findings in primary AML patient samples. Expression of SPRY3 and GSK3A was dramatically reduced in AC220-resistant AML samples, and SPRY3-deleted primary AML cells were resistant to AC220. Intriguingly, expression of SPRY3 was greatly reduced in GSK3 knockout AML cells, which positioned SPRY3 downstream of GSK3 in the resistance pathway. Taken together, our study identified novel genes whose loss of function conferred resistance to a selective FLT3 inhibitor, providing new insight into signaling pathways that contribute to acquired resistance in AML. Cancer Res; 77(16); 4402–13. ©2017 AACR.
A Naturally Generated Decoy of the Prostate Apoptosis Response-4 Protein Overcomes Therapy Resistance in Tumors
Authors: Hebbar Nikhil , Burikhanov Ravshan , Shukla Nidhi , Qiu Shirley , Zhao Yanming , Elenitoba-Johnson Kojo S.J. , Rangnekar Vivek M. 
Published: June 2017

Abstract
Primary tumors are often heterogeneous, composed of therapy-sensitive and emerging therapy-resistant cancer cells. Interestingly, treatment of therapy-sensitive tumors in heterogeneous tumor microenvironments results in apoptosis of therapy-resistant tumors. In this study, we identify a prostate apoptosis response-4 (Par-4) amino-terminal fragment (PAF) that is released by diverse therapy-sensitive cancer cells following therapy-induced caspase cleavage of the tumor suppressor Par-4 protein. PAF caused apoptosis in cancer cells resistant to therapy and inhibited tumor growth. A VASA segment of Par-4 mediated its binding and degradation by the ubiquitin ligase Fbxo45, resulting in loss of Par-4 proapoptotic function. Conversely, PAF, which contains this VASA segment, competitively bound to Fbxo45 and rescued Par-4–mediated induction of cancer cell–specific apoptosis. Collectively, our findings identify a molecular decoy naturally generated during apoptosis that inhibits a ubiquitin ligase to overcome therapy resistance in tumors. Cancer Res; 77(15); 4039–50. ©2017 AACR.
Acetylation of Mastermind-like 1 by p300 Drives the Recruitment of NACK to Initiate Notch-Dependent Transcription
Authors: Jin Ke , Zhou Wen , Han Xiaoqing , Wang Zhiqiang , Li Bin , Jeffries Shawn , Tao Wensi , Robbins David J. , Capobianco Anthony J. 
Published: June 2017

Abstract
Although it has long been appreciated that p300 acts as a critical Notch coactivator, the mechanistic details of p300 in Notch-mediated transcription remain unclear. We previously demonstrated that PEAK1-related kinase activating pseudokinase 1 (NACK), also known as SGK223, is a critical coactivator of Notch signaling and binds to the Notch1 ternary complex. Herein we report that p300 and CBP acetylate Mastermind-like 1 (Maml1) on amino acid residues K188 and K189 to recruit NACK to the Notch1 ternary complex, which results in the recruitment of RNA polymerase II to initiate transcription. NACK is recruited to the ternary complexes containing Maml1 and Maml3, but not Maml2. Simultaneous inhibition of p300/CBP and Notch has a synergistic effect in esophageal adenocarcinoma. In summary, this study provides a deeper mechanistic understanding of the assembly of the Notch transcriptional complex and provides rationale and proof of concept for a combinatorial therapeutic attack on Notch-dependent cancers. Cancer Res; 77(16); 4228–37. ©2017 AACR.