bluuebunny/crossref_metadata_2025_split huggingface dataset:
The complementary and divergent roles of uncoupling proteins 1 and 3 in thermoregulation
Authors: Riley Christopher L. , Dao Christine , Kenaston M. Alexander , Muto Luigina , Kohno Shohei , Nowinski Sara M. , Solmonson Ashley D. , Pfeiffer Matthew , Sack Michael N. , Lu Zhongping , Fiermonte Giuseppe , Sprague Jon E. , Mills Edward M. 
Published: September 2016

Key points
Both uncoupling protein 1 (UCP1) and UCP3 are important for mammalian thermoregulation.
UCP1 and UCP3 in brown adipose tissue mediate early and late phases of sympathomimetic thermogenesis, respectively.
Lipopolysaccharide thermogenesis requires skeletal muscle UCP3 but not UCP1.
Acute noradrenaline‐induced hyperthermia requires UCP1 but not UCP3.
Loss of both UCP1 and UCP3 accelerate the loss of body temperature compared to UCP1KO alone during acute cold exposure.
AbstractUncoupling protein 1 (UCP1) is the established mediator of brown adipose tissue‐dependent thermogenesis. In contrast, the role of UCP3, expressed in both skeletal muscle and brown adipose tissue, in thermoregulatory physiology is less well understood. Here, we show that mice lacking UCP3 (UCP3KO) have impaired sympathomimetic (methamphetamine) and completely abrogated lipopolysaccharide (LPS) thermogenesis, but a normal response to noradrenaline. By comparison, UCP1 knockout (UCP1KO) mice exhibit blunted methamphetamine and fully inhibited noradrenaline thermogenesis, but an increased febrile response to LPS. We further establish that mice lacking both UCP1 and 3 (UCPDK) fail to show methamphetamine‐induced hyperthermia, and have a markedly accelerated loss of body temperature and survival after cold exposure compared to UCP1KO mice. Finally, we show that skeletal muscle‐specific human UCP3 expression is able to significantly rescue LPS, but not sympathomimetic thermogenesis blunted in UCP3KO mice. These studies identify UCP3 as an important mediator of physiological thermogenesis and support a renewed focus on targeting UCP3 in metabolic physiology.
In Vitro
and
In Vivo
Activities of a Bi-Aryl Oxazolidinone, RBx 11760, against Gram-Positive Bacteria
Authors: Barman Tarani Kanta , Kumar Manoj , Mathur Tarun , Chaira Tridib , Ramkumar G. , Kalia Vandana , Rao Madhvi , Pandya Manisha , Yadav Ajay Singh , Das Biswajit , Upadhyay Dilip J. , Hamidullah  , Konwar Rituraj , Raj V. Samuel , Singh Harpal 
Published: September 2016

ABSTRACT

RBx 11760, a bi-aryl oxazolidinone, was investigated for antibacterial activity against Gram-positive bacteria. The MIC
90
s of RBx 11760 and linezolid against
Staphylococcus aureus
were 2 and 4 mg/liter, against
Staphylococcus epidermidis
were 0.5 and 2 mg/liter, and against
Enterococcus
were 1 and 4 mg/liter, respectively. Similarly, against
Streptococcus pneumoniae
the MIC
90
s of RBx 11760 and linezolid were 0.5 and 2 mg/liter, respectively. In time-kill studies, RBx 11760, tedizolid, and linezolid exhibited bacteriostatic effect against all tested strains except
S. pneumoniae
. RBx 11760 showed 2-log
10
kill at 4× MIC while tedizolid and linezolid showed 2-log
10
and 1.4-log
10
kill at 16× MIC, respectively, against methicillin-resistant
S. aureus
(MRSA) H-29. Against
S. pneumoniae
5051, RBx 11760 showed bactericidal activity, with 4.6-log
10
kill at 4× MIC compared to 2.42-log
10
and 1.95-log
10
kill for tedizolid and linezolid, respectively, at 16× MIC. RBx 11760 showed postantibiotic effects (PAE) at 3 h at 4 mg/liter against MRSA H-29, and linezolid showed the same effect at 16 mg/liter. RBx 11760 inhibited biofilm production against methicillin-resistant
S. epidermidis
(MRSE) ATCC 35984 in a concentration-dependent manner. In a foreign-body model, linezolid and rifampin resulted in no advantage over stasis, while the same dose of RBx 11760 demonstrated a significant killing compared to the initial control against
S. aureus
(
P
< 0.05) and MRSE (
P
< 0.01). The difference in killing was statistically significant for the lower dose of RBx 11760 (
P
< 0.05) versus the higher dose of linezolid (
P
> 0.05 [not significant]) in a groin abscess model. In neutropenic mouse thigh infection, RBx 11760 showed stasis at 20 mg/kg of body weight, whereas tedizolid showed the same effect at 40 mg/kg. These data support RBx 11760 as a promising investigational candidate.
The Celecoxib Derivative AR-12 Has Broad-Spectrum Antifungal Activity
In Vitro
and Improves the Activity of Fluconazole in a Murine Model of Cryptococcosis
Authors: Koselny Kristy , Green Julianne , DiDone Louis , Halterman Justin P. , Fothergill Annette W. , Wiederhold Nathan P. , Patterson Thomas F. , Cushion Melanie T. , Rappelye Chad , Wellington Melanie , Krysan Damian J. 
Published: September 2016

ABSTRACT

Only one new class of antifungal drugs has been introduced into clinical practice in the last 30 years, and thus the identification of small molecules with novel mechanisms of action is an important goal of current anti-infective research. Here, we describe the characterization of the spectrum of
in vitro
activity and
in vivo
activity of AR-12, a celecoxib derivative which has been tested in a phase I clinical trial as an anticancer agent. AR-12 inhibits fungal acetyl coenzyme A (acetyl-CoA) synthetase
in vitro
and is fungicidal at concentrations similar to those achieved in human plasma. AR-12 has a broad spectrum of activity, including activity against yeasts (e.g.,
Candida albicans
, non-
albicans Candida
spp.,
Cryptococcus neoformans
), molds (e.g.,
Fusarium
,
Mucor
), and dimorphic fungi (
Blastomyces
,
Histoplasma
, and
Coccidioides
) with MICs of 2 to 4 μg/ml. AR-12 is also active against azole- and echinocandin-resistant
Candida
isolates, and subinhibitory AR-12 concentrations increase the susceptibility of fluconazole- and echinocandin-resistant
Candida
isolates. Finally, AR-12 also increases the activity of fluconazole in a murine model of cryptococcosis. Taken together, these data indicate that AR-12 represents a promising class of small molecules with broad-spectrum antifungal activity.
Nationwide Surveillance of Novel Oxazolidinone Resistance Gene
optrA
in Enterococcus Isolates in China from 2004 to 2014
Authors: Cui Lanqing , Wang Yang , Lv Yuan , Wang Shan , Song Yunjia , Li Yun , Liu Jian , Xue Feng , Yang Weiwei , Zhang Jia 
Published: September 2016

ABSTRACT

A total of 2,201 nonduplicate enterococcal isolates collected from 29 hospitals in 23 cities in China between 2004 and 2014 were screened for the oxazolidinone resistance gene
optrA
; 45 isolates (2.0%) were
optrA
positive with 11 OptrA variants identified. The positive rate of
optrA
increased from 0.4% to 3.9% during the 10-year surveillance period. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence type (MLST) analysis revealed that 37
optrA
-positive
Enterococcus faecalis
isolates clustered into 25 PFGE patterns and 21 sequence types, while 6
Enterococcus faecium
isolates represented 6 PFGE patterns and 6 sequence types. The present study underscores the importance of routine and persistent monitoring of oxazolidinone resistance and
optrA
gene.
Potential Use of Dimethyl Sulfoxide in Treatment of Infections Caused by Pseudomonas aeruginosa
Authors: Guo Qiao , Wu Qiaolian , Bai Dangdang , Liu Yang , Chen Lin , Jin Sheng , Wu Yuting , Duan Kangmin 
Published: September 2016

ABSTRACT

Dimethyl sulfoxide (DMSO) is commonly used as a solvent to dissolve water-insoluble drugs or other test samples in both
in vivo
and
in vitro
experiments. It was observed during our experiment that DMSO at noninhibitory concentrations could significantly inhibit pyocyanin production in the human pathogen
Pseudomonas aeruginosa
. Pyocyanin is an important pathogenic factor whose production is controlled by a cell density-dependent quorum-sensing (QS) system. Investigation of the effect of DMSO on QS showed that DMSO has significant QS antagonistic activities and concentrations of DMSO in the micromolar range attenuated a battery of QS-controlled virulence factors, including rhamnolipid, elastase, and LasA protease production and biofilm formation. Further study indicated that DMSO inhibition of biofilm formation and pyocyanin production was attained by reducing the level of production of an autoinducer molecule of the
rhl
QS system,
N
-butanoyl-
l
-homoserine lactone (C
4
-HSL). In a mouse model of a burn wound infection with
P. aeruginosa
, treatment with DMSO significantly decreased mouse mortality compared with that for mice in the control group. The capacity of DMSO to attenuate the pathogenicity of
P. aeruginosa
points to the potential use of DMSO as an antipathogenic agent for the treatment of
P. aeruginosa
infection. As a commonly used solvent, however, DMSO's impact on bacterial virulence calls for cautionary attention in its usage in biological, medicinal, and clinical studies.
Moxifloxacin Is a Potent
In Vitro
Inhibitor of OCT- and MATE-Mediated Transport of Metformin and Ethambutol
Authors: te Brake Lindsey H. M. , van den Heuvel Jeroen J. M. W. , Buaben Aaron O. , van Crevel Reinout , Bilos Albert , Russel Frans G. , Aarnoutse Rob E. , Koenderink Jan B. 
Published: September 2016

ABSTRACT

It is largely unknown if simultaneous administration of tuberculosis (TB) drugs and metformin leads to drug-drug interactions (DDIs). Disposition of metformin is determined by organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs). Thus, any DDIs would primarily be mediated via these transporters. This study aimed to assess the
in vitro
inhibitory effects of TB drugs (rifampin, isoniazid, pyrazinamide, ethambutol, amikacin, moxifloxacin, and linezolid) on metformin transport and whether TB drugs are also substrates themselves of OCTs and MATEs. HEK293 cells overexpressing OCT1, OCT2, OCT3, MATE1, and MATE2K were used to study TB drug-mediated inhibition of [
14
C]metformin uptake and to test if TB drugs are transporter substrates. Metformin uptake was determined by quantifying [
14
C]metformin radioactivity, and TB drug uptake was analyzed using liquid chromatography-tandem mass spectrometry. DDI indices were calculated (plasma maximum concentrations [
C
max
]/50% inhibitory concentrations [IC
50
]), and based on the literature, a cutoff of >0.1 was assumed to warrant further
in vivo
investigation. Moxifloxacin was the only TB drug identified as a potent inhibitor (DDI index of >0.1) of MATE1- and MATE2K-mediated metformin transport, with IC
50
s of 12 μM (95% confidence intervals [CI], 5.1 to 29 μM) and 7.6 μM (95% CI, 0.2 to 242 μM), respectively. Of all TB drugs, only ethambutol appeared to be a substrate of OCT1, OCT2, OCT3, MATE1, and MATE2K. MATE1-mediated ethambutol uptake was inhibited strongly (DDI index of >0.1) by moxifloxacin (IC
50
, 12 μM [95% CI, 3.4 to 43 μM]). Our findings provide a mechanistic basis for DDI predictions concerning ethambutol. According to international guidelines, an
in vivo
interaction study is warranted for the observed
in vitro
interaction between ethambutol and moxifloxacin.
The Expression of Antibiotic Resistance Methyltransferase Correlates with mRNA Stability Independently of Ribosome Stalling
Authors: Dzyubak Ekaterina , Yap Mee-Ngan F. 
Published: September 2016

ABSTRACT

Members of the Erm methyltransferase family modify 23S rRNA of the bacterial ribosome and render cross-resistance to macrolides and multiple distantly related antibiotics. Previous studies have shown that the expression of
erm
is activated when a macrolide-bound ribosome stalls the translation of the leader peptide preceding the cotranscribed
erm
. Ribosome stalling is thought to destabilize the inhibitory stem-loop mRNA structure and exposes the
erm
Shine-Dalgarno (SD) sequence for translational initiation. Paradoxically, mutations that abolish ribosome stalling are routinely found in hyper-resistant clinical isolates; however, the significance of the stalling-dead leader sequence is largely unknown. Here, we show that nonsense mutations in the
Staphylococcus aureus
ErmB leader peptide (ErmBL) lead to high basal and induced expression of downstream ErmB in the absence or presence of macrolide concomitantly with elevated ribosome methylation and resistance. The overexpression of ErmB is associated with the reduced turnover of the
ermBL-ermB
transcript, and the macrolide appears to mitigate mRNA cleavage at a site immediately downstream of the
ermBL
SD sequence. The stabilizing effect of antibiotics on mRNA is not limited to
ermBL-ermB
; cationic antibiotics representing a ribosome-stalling inducer and a noninducer increase the half-life of specific transcripts. These data unveil a new layer of
ermB
regulation and imply that ErmBL translation or ribosome stalling serves as a “tuner” to suppress aberrant production of ErmB because methylated ribosome may impose a fitness cost on the bacterium as a result of misregulated translation.
Filifactor alocis Promotes Neutrophil Degranulation and Chemotactic Activity
Authors: Armstrong Cortney L. , Miralda Irina , Neff Adam C. , Tian Shifu , Vashishta Aruna , Perez Lisandra , Le Junyi , Lamont Richard J. , Uriarte Silvia M. 
Published: September 2016

ABSTRACTFilifactor alocisis a recently recognized periodontal pathogen; however, little is known regarding its interactions with the immune system. As the first-responder phagocytic cells, neutrophils are recruited in large numbers to the periodontal pocket, where they play a crucial role in the innate defense of the periodontium. Thus, in order to colonize, successful periodontal pathogens must devise means to interfere with neutrophil chemotaxis and activation. In this study, we assessed major neutrophil functions, including degranulation and cell migration, associated with the p38 mitogen-activated protein kinase (MAPK) signaling pathway upon challenge withF. alocis.Under conditions lacking a chemotactic gradient,F. alocis-challenged neutrophils had increased migration compared to uninfected cells, indicating thatF. alocisincreases chemokinesis in human neutrophils. In addition, neutrophil chemotaxis induced by interleukin-8 was significantly enhanced when cells were challenged withF. alocis, compared to noninfected cells. Similar to live bacteria, heat-killedF. alocisinduced both random and directed migration of human neutrophils. The interaction ofF. alociswith Toll-like receptor 2 induced granule exocytosis along with a transient ERK1/2 and sustained p38 MAPK activation. Moreover,F. alocis-induced secretory vesicle and specific granule exocytosis were p38 MAPK dependent. Blocking neutrophil degranulation with TAT-SNAP23 fusion protein significantly reduced the chemotactic and random migration induced byF. alocis. Therefore, we propose that induction of random migration byF. alociswill prolong neutrophil traffic time in the gingival tissue, and subsequent degranulation will contribute to tissue damage.
Thermal Unfolding of the Pertussis Toxin S1 Subunit Facilitates Toxin Translocation to the Cytosol by the Mechanism of Endoplasmic Reticulum-Associated Degradation
Authors: Banerjee Tuhina , Cilenti Lucia , Taylor Michael , Showman Adrienne , Tatulian Suren A. , Teter Ken 
Published: September 2016

ABSTRACT
Pertussis toxin (PT) moves from the host cell surface to the endoplasmic reticulum (ER) by retrograde vesicular transport. The catalytic PTS1 subunit dissociates from the rest of the toxin in the ER and then shifts to a disordered conformation which may trigger its export to the cytosol through the quality control mechanism of ER-associated degradation (ERAD). Functional roles for toxin instability and ERAD in PTS1 translocation have not been established. We addressed these issues with the use of a surface plasmon resonance system to quantify the cytosolic pool of PTS1 from intoxicated cells. Only 3% of surface-associated PTS1 reached the host cytosol after 3 h of toxin exposure. This represented, on average, 38,000 molecules of cytosolic PTS1 per cell. Cells treated with a proteasome inhibitor contained larger quantities of cytosolic PTS1. Stabilization of the dissociated PTS1 subunit with chemical chaperones inhibited toxin export to the cytosol and blocked PT intoxication. ERAD-defective cell lines likewise exhibited reduced quantities of cytosolic PTS1 and PT resistance. These observations identify the unfolding of dissociated PTS1 as a trigger for its ERAD-mediated translocation to the cytosol.
The Helical Shape of Campylobacter jejuni Promotes
In Vivo
Pathogenesis by Aiding Transit through Intestinal Mucus and Colonization of Crypts
Authors: Stahl Martin , Frirdich Emilisa , Vermeulen Jenny , Badayeva Yuliya , Li Xiaoxia , Vallance Bruce A. , Gaynor Erin C. 
Published: September 2016

ABSTRACT

Campylobacter jejuni
is a helix-shaped enteric bacterial pathogen and a common cause of gastroenteritis. We recently developed a mouse model for this human pathogen utilizing the SIGIRR-deficient mouse strain, which exhibits significant intestinal inflammation in response to intestinal
C. jejuni
infection. In the current study, this mouse model was used to define whether
C. jejuni
's characteristic helical shape plays a role in its ability to colonize and elicit inflammation in the mouse intestine. Mice were infected with the previously characterized straight-rod Δ
pgp1
and Δ
pgp2
mutant strains, along with a newly characterized curved-rod Δ
1228
mutant strain. We also compared the resultant infections and pathology to those elicited by the helix-shaped wild-type
C. jejuni
and complemented strains. Despite displaying wild-type colonization of the intestinal lumen, the straight-rod Δ
pgp1
and Δ
pgp2
mutants were essentially nonpathogenic, while all strains with a curved or helical shape retained their expected virulence. Furthermore, analysis of
C. jejuni
localization within the ceca of infected mice determined that the primary difference between the rod-shaped, nonpathogenic mutants and the helix-shaped, pathogenic strains was the ability to colonize intestinal crypts. Rod-shaped mutants appeared unable to colonize intestinal crypts due to an inability to pass through the intestinal mucus layer to directly contact the epithelium. Together, these results support a critical role for
C. jejuni
's helical morphology in enabling it to traverse and colonize the mucus-filled intestinal crypts of their host, a necessary step required to trigger intestinal inflammation in response to
C. jejuni
.
The Topology of the
l
-Arginine Exporter ArgO Conforms to an N
in
-C
out
Configuration in Escherichia coli: Requirement for the Cytoplasmic N-Terminal Domain, Functional Helical Interactions, and an Aspartate Pair for ArgO Function
Authors: Pathania Amit , Gupta Arvind Kumar , Dubey Swati , Gopal Balasubramanian , Sardesai Abhijit A. 
Published: September 2016

ABSTRACT

ArgO and LysE are members of the LysE family of exporter proteins and ordinarily mediate the export of
l
-arginine (Arg) in
Escherichia coli
and
l
-lysine (Lys) and Arg in
Corynebacterium glutamicum
, respectively. Under certain conditions, ArgO also mediates Lys export. To delineate the arrangement of ArgO in the cytoplasmic membrane of
E. coli
, we have employed a combination of cysteine accessibility
in situ
, alkaline phosphatase fusion reporters, and protein modeling to arrive at a topological model of ArgO. Our studies indicate that ArgO assumes an N
in
-C
out
configuration, potentially forming a five-transmembrane helix bundle flanked by a cytoplasmic N-terminal domain (NTD) comprising roughly its first 38 to 43 amino acyl residues and a short periplasmic C-terminal region (CTR). Mutagenesis studies indicate that the CTR, but not the NTD, is dispensable for ArgO function
in vivo
and that a pair of conserved aspartate residues, located near the opposing edges of the cytoplasmic membrane, may play a pivotal role in facilitating transmembrane Arg flux. Additional studies on amino acid substitutions that impair ArgO function
in vivo
and their derivatives bearing compensatory amino acid alterations indicate a role for intramolecular interactions in the Arg export mechanism, and some interactions are corroborated by normal-mode analyses. Lastly, our studies suggest that ArgO may exist as a monomer
in vivo
, thus highlighting the requirement for intramolecular interactions in ArgO, as opposed to interactions across multiple ArgO monomers, in the formation of an Arg-translocating conduit.

IMPORTANCE
The orthologous proteins LysE of
C. glutamicum
and ArgO of
E. coli
function as exporters of the basic amino acids
l
-arginine and
l
-lysine and the basic amino acid
l
-arginine, respectively, and LysE can functionally substitute for ArgO when expressed in
E. coli
. Notwithstanding this functional equivalence, studies reported here show that ArgO possesses a membrane topology that is distinct from that reported for LysE, with substantial variation in the topological arrangement of the proximal one-third portions of the two exporters. Additional genetic and
in silico
studies reveal the importance of (i) the cytoplasmic N-terminal domain, (ii) a pair of conserved aspartate residues, and (iii) potential intramolecular interactions in ArgO function and indicate that an Arg-translocating conduit is formed by a monomer of ArgO.
Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination
Authors: Korza George , Setlow Barbara , Rao Lei , Li Qiao , Setlow Peter 
Published: September 2016

ABSTRACT

rRNAs of dormant spores of
Bacillus subtilis
were >95% degraded during extended incubation at 50°C, as reported previously (E. Segev, Y. Smith, and S. Ben-Yehuda, Cell 148:139–114, 2012, doi:
http://dx.doi.org/10.1016/j.cell.2011.11.059
), and this was also true of spores of
Bacillus megaterium
. Incubation of spores of these two species for ∼20 h at 75 to 80°C also resulted in the degradation of all or the great majority of the 23S and 16S rRNAs, although this rRNA degradation was slower than nonenzymatic hydrolysis of purified rRNAs at these temperatures. This rRNA degradation at high temperature generated almost exclusively oligonucleotides with minimal levels of mononucleotides. RNase Y, suggested to be involved in rRNA hydrolysis during
B. subtilis
spore incubation at 50°C, did not play a role in
B. subtilis
spore rRNA breakdown at 80°C. Twenty hours of incubation of
Bacillus
spores at 70°C also decreased the already minimal levels of ATP in dormant spores 10- to 30-fold, to ≤0.01% of the total free adenine nucleotide levels. Spores depleted of rRNA were viable and germinated relatively normally, often even faster than starting spores. Their return to vegetative growth was also similar to that of untreated spores for
B. megaterium
spores and slower for heat-treated
B. subtilis
spores; accumulation of rRNA took place only after completion of spore germination. These findings thus strongly suggest that protein synthesis is not essential for
Bacillus
spore germination.

IMPORTANCE
A recent report (L. Sinai, A. Rosenberg, Y. Smith, E. Segev, and S. Ben-Yehuda, Mol Cell 57:3486–3495, 2015, doi:
http://dx.doi.org/10.1016/j.molcel.2014.12.019
) suggested that protein synthesis is essential for early steps in the germination of dormant spores of
Bacillus subtilis
. If true, this would be a paradigm shift in our understanding of spore germination. We now show that essentially all of the rRNA can be eliminated from spores of
Bacillus megaterium
or
B. subtilis
, and these rRNA-depleted spores are viable and germinate as well as or better than spores with normal rRNA levels. Thus, protein synthesis is not required in the process of spore germination.