bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adiponectin is sufficient, but not required, for exercise‐induced increases in the expression of skeletal muscle mitochondrial enzymes
Authors: Ritchie Ian R. W. , MacDonald Tara L. , Wright David C. , Dyck David J. 
Published: April 2014

Key points
Adiponectin is a regulator of skeletal muscle mitochondrial biogenesis. Previous research using the ob/ob mouse (leptin deficient, low adiponectin) has suggested that the presence of adipokines, including adiponectin, is necessary for exercise‐induced increases in mitochondrial content.
In the current study, we examined the importance of adiponectin as a regulator of skeletal muscle mitochondrial content in response to exercise by comparing wildtype and adiponectin deficient mice.
Adiponectin deficient mice showed no differences in resting , RER, or time to exhaustion during exercise when compared to wildtype mice. There were no differences in various protein markers of mitochondrial content.
A single bout of treadmill running increased the mRNA expression of mitochondrial proteins similarly in wildtype and adiponectin deficient mice. Chronic exercise (8 weeks) also increased the protein content of mitochondrial markers similarly in wildtype and adiponectin deficient mice.
We conclude that Ad is not required for exercise‐induced increases in muscle mitochondrial proteins.
AbstractAdiponectin (Ad) has been proposed to be a regulator of mitochondrial biogenesis in skeletal muscle, and necessary for exercise‐induced increases in mitochondrial content. We first confirmed that Ad could acutely increase the expression of mitochondrial proteins during a 10 h incubation in isolated soleus and extensor digitorum longus (EDL) muscles. Next, we further examined the role of Ad as a regulator of mitochondrial content using Ad knockout (AdKO) mice. The AdKO animals showed no differences in resting , respiratory exchange ratio, or in time to exhaustion during exercise when compared to wild‐type (WT) mice. There was a reduction in resting palmitate oxidation in isolated soleus from AdKO animals (−23%, P < 0.05) but not EDL, and 5‐aminoimidazole‐4‐carboxamide (AICAR)‐stimulated palmitate oxidation was similar in both genotypes regardless of muscle. There were no differences in protein markers of mitochondrial content (COX4, CORE1, CS, PDHE1α) in red and white gastrocnemius between WT and AdKO animals. A single bout of treadmill running increased the phosphorylation of AMP‐activated protein kinase (AMPK) and the mRNA expression of mitochondrial proteins in red and white gastrocnemius in both WT and AdKO animals, with no differences between genotypes. Finally, 8 weeks of chronic exercise training increased the protein content of mitochondrial markers similarly (∼25–35%) in red gastrocnemius from both WT and AdKO mice. Collectively, our results demonstrate that the absence of Ad is not accompanied by reductions in mitochondrial protein content, or a reduction in aerobic exercise capacity. We conclude that Ad is not required for the maintenance of mitochondrial content, or for exercise‐induced increases in skeletal muscle mitochondrial proteins.
Assessment of Mycobacterium tuberculosis Pantothenate Kinase Vulnerability through Target Knockdown and Mechanistically Diverse Inhibitors
Authors: Reddy B. K. Kishore , Landge Sudhir , Ravishankar Sudha , Patil Vikas , Shinde Vikas , Tantry Subramanyam , Kale Manoj , Raichurkar Anandkumar , Menasinakai Sreenivasaiah , Mudugal Naina Vinay , Ambady Anisha , Ghosh Anirban , Tunduguru Ragadeepthi , Kaur Parvinder , Singh Ragini , Kumar Naveen , Bharath Sowmya , Sundaram Aishwarya , Bhat Jyothi , Sambandamurthy Vasan K. , Björkelid Christofer , Jones T. Alwyn , Das Kaveri , Bandodkar Balachandra , Malolanarasimhan Krishnan , Mukherjee Kakoli , Ramachandran Vasanthi 
Published: April 2014

ABSTRACT

Pantothenate kinase (PanK) catalyzes the phosphorylation of pantothenate, the first committed and rate-limiting step toward coenzyme A (CoA) biosynthesis. In our earlier reports, we had established that the type I isoform encoded by the
coaA
gene is an essential pantothenate kinase in
Mycobacterium tuberculosis
, and this vital information was then exploited to screen large libraries for identification of mechanistically different classes of PanK inhibitors. The present report summarizes the synthesis and expansion efforts to understand the structure-activity relationships leading to the optimization of enzyme inhibition along with antimycobacterial activity. Additionally, we report the progression of two distinct classes of inhibitors, the triazoles, which are ATP competitors, and the biaryl acetic acids, with a mixed mode of inhibition. Cocrystallization studies provided evidence of these inhibitors binding to the enzyme. This was further substantiated with the biaryl acids having MIC against the wild-type
M. tuberculosis
strain and the subsequent establishment of a target link with an upshift in MIC in a strain overexpressing PanK. On the other hand, the ATP competitors had cellular activity only in a
M. tuberculosis
knockdown strain with reduced PanK expression levels. Additionally,
in vitro
and
in vivo
survival kinetic studies performed with a
M. tuberculosis
PanK (
Mt
PanK) knockdown strain indicated that the target levels have to be significantly reduced to bring in growth inhibition. The dual approaches employed here thus established the poor vulnerability of PanK in
M. tuberculosis
.
Bumped Kinase Inhibitor 1294 Treats Established Toxoplasma gondii Infection
Authors: Doggett J. Stone , Ojo Kayode K. , Fan Erkang , Maly Dustin J. , Van Voorhis Wesley C. 
Published: April 2014

ABSTRACT

Toxoplasma gondii
is a unicellular parasite that causes severe brain and eye disease. Current drugs for
T. gondii
are limited by toxicity. Bumped kinase inhibitors (BKIs) selectively inhibit calcium-dependent protein kinases of the apicomplexan pathogens
T. gondii
, cryptosporidia, and plasmodia. A lead anti-
Toxoplasma
BKI, 1294, has been developed to be metabolically stable and orally bioavailable. Herein, we demonstrate the oral efficacy of 1294 against toxoplasmosis
in vivo
.
Evaluation of Imipenem for Prophylaxis and Therapy of Yersinia pestis Delivered by Aerosol in a Mouse Model of Pneumonic Plague
Authors: Heine Henry S. , Louie Arnold , Adamovicz Jeffrey J. , Amemiya Kei , Fast Randy L. , Miller Lynda , Opal Steven M. , Palardy John , Parejo Nicolas A. , Sörgel Fritz , Kinzig-Schippers Martina , Drusano George L. 
Published: April 2014

ABSTRACTIt has been previously shown that mice subjected to an aerosol exposure toYersinia pestisand treated with β-lactam antibiotics after a delay of 42 h died at an accelerated rate compared to controls. It was hypothesized that endotoxin release in antibiotic-treated mice accounted for the accelerated death rate in the mice exposed to aerosolY. pestis. Imipenem, a β-lactam antibiotic, binds to penicillin binding protein 2 with the highest affinity and produces rounded cells. The binding of imipenem causes cells to lyse quickly and thereby to release less free endotoxin. Two imipenem regimens producing fractions of time that the concentration of free, unbound drug was above the MIC (fT>MIC) of approximately 25% (6/24 h) and 40% (9.5/24 h) were evaluated. In the postexposure prophylaxis study, the 40% and 25% regimens produced 90% and 40% survivorship, respectively. In the 42-h treatment study, both regimens demonstrated a 40 to 50% survivorship at therapy cessation and some deaths thereafter, resulting in a 30% survivorship. As this was an improvement over the results with other β-lactams, a comparison of both endotoxin and cytokine levels in mice treated with imipenem and ceftazidime (a β-lactam previously demonstrated to accelerate death in mice during treatment) was performed and supported the original hypotheses; however, the levels observed in animals treated with ciprofloxacin (included as an unrelated antibiotic that is also bactericidal but should cause little lysis due to a different mode of action) were elevated and significantly (7-fold) higher than those with ceftazidime.
In Vitro
and
In Vivo
Efficacy of Novel Flavonoid Dimers against Cutaneous Leishmaniasis
Authors: Wong Iris L. K. , Chan Kin-Fai , Chen Yun-Fu , Lun Zhao-Rong , Chan Tak Hang , Chow Larry M. C. 
Published: April 2014

ABSTRACT

Treatment of leishmaniasis by chemotherapy remains a challenge because of limited efficacy, toxic side effects, and drug resistance. We previously reported that synthetic flavonoid dimers have potent antipromastigote and antiamastigote activity against
Leishmania donovani
, the causative agent of visceral leishmaniasis. Here, we further investigate their leishmanicidal activities against cutaneous
Leishmania
species. One of the flavonoid dimers (compound 39) has marked antipromastigote (50% inhibitory concentrations [IC
50
s], 0.19 to 0.69 μM) and antiamastigote (IC
50
s, 0.17 to 2.2 μM) activities toward different species of
Leishmania
that cause cutaneous leishmaniasis, including
Leishmania amazonensis
,
Leishmania braziliensis
,
Leishmania tropica
, and
Leishmania major
. Compound 39 is not toxic to peritoneal elicited macrophages, with IC
50
values higher than 88 μM. In the mouse model of cutaneous leishmaniasis induced by subcutaneous inoculation of
L. amazonensis
in mouse footpads, intralesional administration of 2.5 mg/kg of body weight of compound 39.HCl can reduce footpad thickness by 36%, compared with that of controls values. The amastigote load in the lesions was reduced 20-fold. The present study suggests that flavonoid dimer 39 represents a new class of safe and effective leishmanicidal agent against visceral and cutaneous leishmaniasis.
In Vitro
and
In Vivo
Activities of HPi1, a Selective Antimicrobial against Helicobacter pylori
Authors: Gavrish Ekaterina , Shrestha Binu , Chen Chao , Lister Ida , North E. Jeffrey , Yang Lei , Lee Richard E. , Han Angel , Williams Bronwyn , Charnuska David , Coleman Ken , Lewis Kim , LaFleur Michael D. 
Published: April 2014

ABSTRACT

A high-throughput screen (HTS) was performed to identify molecules specifically active against
Helicobacter pylori
, the causative agent of peptic ulcer and gastric carcinoma. Currently, treatment of
H. pylori
infection is suboptimal, with failure rates approaching 25%, despite triple therapy with two broad-spectrum antibiotics and a proton pump inhibitor or quadruple therapy with added bismuth. The HTS was performed in 384-well plates, and reduction of the metabolic indicator resazurin was used as a reporter for cell growth. Diverse molecules from commercial sources were identified as hits, and
in vitro
validations included measurements of MIC and time-dependent killing as well as anaerobic susceptibility testing against a panel of gut microbes.
In vivo
validation included testing in the mouse model of
H. pylori
infection. The small molecule HPi1 (3-hydrazinoquinoxaline-2-thiol) had excellent potency, with an MIC of 0.08 to 0.16 μg/ml and good selectivity for
H. pylori
compared to a panel of commensal bacteria. HPi1 was also effective in a mouse model of
H. pylori
infection, reducing colony counts to below the limit of detection after oral dosing of 25 mg/kg/day for 3 days. HPi1 is a promising lead in the search for more effective and specific
H. pylori
therapeutics.
Factors Associated with Ceftriaxone Nonsusceptibility of Streptococcus pneumoniae: Analysis of South African National Surveillance Data, 2003 to 2010
Authors: von Mollendorf Claire , Cohen Cheryl , de Gouveia Linda , Quan Vanessa , Meiring Susan , Feldman Charles , Klugman Keith P. , von Gottberg Anne 
Published: April 2014

ABSTRACT

It is important to monitor β-lactam antimicrobial nonsusceptibility trends for
Streptococcus pneumoniae
to inform empirical treatment guidelines. In this study, we describe penicillin and ceftriaxone susceptibility trends using national laboratory-based pneumococcal surveillance data from 2003 to 2010. A sentinel enhanced-site patient subset (2009 to 2010) contributed to the risk factor and mortality analyses. We included 9,218 invasive pneumococcal disease (IPD) cases for trend analyses and 2,854 IPD cases for risk factor and mortality analyses. Overall, we detected no significant changes in penicillin (patients <5 years of age,
P
= 0.50; patients ≥5 years of age,
P
= 0.05) or ceftriaxone nonsusceptibility rates (patients <5 years of age,
P
= 0.21; patients ≥5 years of age,
P
= 0.60). Factors associated with ceftriaxone nonsusceptibility on multivariate analysis were an age of <5 years (<1 year of age: adjusted odds ratio [aOR], 2.87; 95% confidence interval [CI], 1.70 to 4.86; 1 to 4 years of age: aOR, 2.58; 95% CI, 1.53 to 4.35, versus 25 to 44 years of age), province (Gauteng [aOR, 2.46; 95% CI, 1.26 to 4.84], and Northern Cape [aOR, 4.52; 95% CI, 1.95 to 10.52] versus KwaZulu-Natal), β-lactam use within 24 h preceding admission (aOR, 2.52; 95% CI, 1.41 to 4.53), and 13-valent vaccine serotypes (aOR, 51.64; 95% CI, 7.18 to 371.71). Among patients ≥5 years of age with meningitis who were treated according to current guidelines, HIV-infected patients (aOR, 2.94; 95% CI, 1.32 to 6.54) and patients infected with ceftriaxone-nonsusceptible isolates (aOR, 3.17; 95% CI, 1.27 to 7.89) had increased mortality rates. Among children <5 years of age with meningitis, mortality was increased in HIV-infected patients (aOR, 3.04; 95% CI, 1.40 to 6.56) but not in those with ceftriaxone-nonsusceptible isolates. Penicillin and ceftriaxone nonsusceptibility remained stable over the study period. Ceftriaxone nonsusceptibility was associated with increased mortality among patients ≥5 years of age with meningitis. The introduction of a pneumococcal conjugate vaccine may reduce ceftriaxone-nonsusceptible meningitis.
Characterization of
sal
(A), a Novel Gene Responsible for Lincosamide and Streptogramin A Resistance in Staphylococcus sciuri
Authors: Hot Chloé , Berthet Nicolas , Chesneau Olivier 
Published: April 2014

ABSTRACT

Natural resistance to lincosamides and streptogramins A (LS
A
), which is a species characteristic of
Bacillus subtilis
and
Enterococcus faecalis
, has never been documented in the
Staphylococcus
genus. We investigate here the molecular basis of the LS
A
phenotype exhibited by seven reference strains of
Staphylococcus sciuri
, including the type strains of the three described subspecies. By whole-genome sequencing of strain ATCC 29059, we identified a candidate gene that encodes an ATP-binding cassette protein similar to the Lsa and VmlR resistance determinants. Isolation and reverse transcription-quantitative PCR (qRT-PCR) expression studies confirmed that Sal(A) can confer a moderate resistance to lincosamides (8 times the MIC of lincomycin) and a high-level resistance to streptogramins A (64 times the MIC of pristinamycin II). The chromosomal location of
sal
(A) between two housekeeping genes of the staphylococcal core genome supports the gene's ancient origins and thus innate resistance to these antimicrobials within
S. sciuri
subspecies.
Vaccination with a Single CD4 T Cell Peptide Epitope from a Salmonella Type III-Secreted Effector Protein Provides Protection against Lethal Infection
Authors: Kurtz Jonathan R , Petersen Hailey E. , Frederick Daniel R. , Morici Lisa A. , McLachlan James B. 
Published: April 2014

ABSTRACTSalmonellainfections affect millions worldwide and remain a significant cause of morbidity and mortality. It is known from mouse studies that CD4 T cells are essential mediators of immunity againstSalmonellainfection, yet it is not clear whether targeting CD4 T cell responses directly with peptide vaccines againstSalmonellacan be effective in combating infection. Additionally, it is not known whether T cell responses elicited againstSalmonellasecreted effector proteins can provide protective immunity against infection. In this study, we investigated both of these possibilities using prime-boost immunization of susceptible mice with a single CD4 T cell peptide epitope fromSalmonellasecreted effector protein I (SseI), a component of theSalmonellatype III secretion system. This immunization conferred significant protection against lethal oral infection, equivalent to that conferred by whole heat-killedSalmonellabacteria. Surprisingly, a well-characterized T cell epitope from the flagellar protein FliC afforded no protection compared to immunization with an irrelevant control peptide. The protective response appeared to be most associated with polyfunctional CD4 T cells raised against the SseI peptide, since no antibodies were produced against any of the peptides and very little CD8 T cell response was observed. Overall, this study demonstrates that eliciting CD4 T cell responses against components of theSalmonellatype III secretion system can contribute to protection against infection and should be considered in the design of futureSalmonellasubunit vaccines.
In Vivo
Splenic Clearance Correlates with
In Vitro
Deformability of Red Blood Cells from Plasmodium yoelii-Infected Mice
Authors: Huang Sha , Amaladoss Anburaj , Liu Min , Chen Huichao , Zhang Rou , Preiser Peter R. , Dao Ming , Han Jongyoon 
Published: April 2014

ABSTRACT

Recent experimental and clinical studies suggest a crucial role of mechanical splenic filtration in the host's defense against malaria parasites. Subtle changes in red blood cell (RBC) deformability, caused by infection or drug treatment, could influence the pathophysiological outcome. However,
in vitro
deformability measurements have not been directly linked
in vivo
with the splenic clearance of RBCs. In this study, mice infected with malaria-inducing
Plasmodium yoelii
revealed that chloroquine treatment could lead to significant alterations to RBC deformability and increase clearance of both infected and uninfected RBCs
in vivo
. These results have clear implications for the mechanism of human malarial anemia, a severe pathological condition affecting malaria patients.
IsdC from Staphylococcus lugdunensis Induces Biofilm Formation under Low-Iron Growth Conditions
Authors: Missineo Antonino , Di Poto Antonella , Geoghegan Joan A. , Rindi Simonetta , Heilbronner Simon , Gianotti Valentina , Arciola Carla Renata , Foster Timothy J. , Speziale Pietro , Pietrocola Giampiero 
Published: April 2014

ABSTRACT

Staphylococcus lugdunensis
is a coagulase-negative staphylococcus that is a commensal of humans and an opportunistic pathogen. It can cause a spectrum of infections, including those that are associated with the ability to form biofilm, such as occurs with endocarditis or indwelling medical devices. The genome sequences of two strains revealed the presence of orthologues of the
ica
genes that are responsible for synthesis of poly-
N
-acetylglucosamine (PNAG) that is commonly associated with biofilm in other staphylococci. However, we discovered that biofilm formed by a panel of
S. lugdunensis
isolates growing in iron-restricted medium was susceptible to degradation by proteases and not by metaperiodate, suggesting that the biofilm matrix comprised proteins and not PNAG. When the iron concentration was raised to 1 mM biofilm formation by all strains tested was greatly reduced. A mutant of strain N920143 lacking the entire locus that encodes iron-regulated surface determinant (Isd) proteins was defective in biofilm formation under iron-limited conditions. An IsdC-null mutant was defective, whereas IsdK, IsdJ, and IsdB mutants formed biofilm to the same level as the parental strain. Expression of IsdC was required both for the primary attachment to unconditioned polystyrene and for the accumulation phase of biofilm involving cell-cell interactions. Purified recombinant IsdC protein formed dimers in solution and
Lactococcus lactis
cells expressing only IsdC adhered to immobilized recombinant IsdC but not to IsdJ, IsdK, or IsdB. This is consistent with a specific homophilic interaction between IsdC molecules on neighboring cells contributing to accumulation of
S. lugdunensis
biofilm
in vivo
.
Deletion of Braun Lipoprotein and Plasminogen-Activating Protease-Encoding Genes Attenuates Yersinia pestis in Mouse Models of Bubonic and Pneumonic Plague
Authors: van Lier Christina J. , Sha Jian , Kirtley Michelle L. , Cao Anthony , Tiner Bethany L. , Erova Tatiana E. , Cong Yingzi , Kozlova Elena V. , Popov Vsevolod L. , Baze Wallace B. , Chopra Ashok K. 
Published: April 2014

ABSTRACT

Currently, there is no FDA-approved vaccine against
Yersinia pestis
, the causative agent of bubonic and pneumonic plague. Since both humoral immunity and cell-mediated immunity are essential in providing the host with protection against plague, we developed a live-attenuated vaccine strain by deleting the Braun lipoprotein (
lpp
) and plasminogen-activating protease (
pla
) genes from
Y. pestis
CO92. The Δ
lpp
Δ
pla
double isogenic mutant was highly attenuated in evoking both bubonic and pneumonic plague in a mouse model. Further, animals immunized with the mutant by either the intranasal or the subcutaneous route were significantly protected from developing subsequent pneumonic plague. In mice, the mutant poorly disseminated to peripheral organs and the production of proinflammatory cytokines concurrently decreased. Histopathologically, reduced damage to the lungs and livers of mice infected with the Δ
lpp
Δ
pla
double mutant compared to the level of damage in wild-type (WT) CO92-challenged animals was observed. The Δ
lpp
Δ
pla
mutant-immunized mice elicited a humoral immune response to the WT bacterium, as well as to CO92-specific antigens. Moreover, T cells from mutant-immunized animals exhibited significantly higher proliferative responses, when stimulated
ex vivo
with heat-killed WT CO92 antigens, than mice immunized with the same sublethal dose of WT CO92. Likewise, T cells from the mutant-immunized mice produced more gamma interferon (IFN-γ) and interleukin-4. These animals had an increasing number of tumor necrosis factor alpha (TNF-α)-producing CD4
+
and CD8
+
T cells than WT CO92-infected mice. These data emphasize the role of TNF-α and IFN-γ in protecting mice against pneumonic plague. Overall, our studies provide evidence that deletion of the
lpp
and
pla
genes acts synergistically in protecting animals against pneumonic plague, and we have demonstrated an immunological basis for this protection.
Vitamin D Deficiency Reduces the Immune Response, Phagocytosis Rate, and Intracellular Killing Rate of Microglial Cells
Authors: Djukic Marija , Onken Marie Luise , Schütze Sandra , Redlich Sandra , Götz Alexander , Hanisch Uwe-Karsten , Bertsch Thomas , Ribes Sandra , Hanenberg Andrea , Schneider Simon , Bollheimer Cornelius , Sieber Cornel , Nau Roland 
Published: April 2014

ABSTRACTMeningitis and meningoencephalitis caused byEscherichia coliare associated with high rates of mortality and neurological sequelae. A high prevalence of neurological disorders has been observed in geriatric populations at risk of hypovitaminosis D. Vitamin D has potent effects on human immunity, including induction of antimicrobial peptides (AMPs) and suppression of T-cell proliferation, but its influence on microglial cells is unknown. The purpose of the present study was to determine the effects of vitamin D deficiency on the phagocytosis rate, intracellular killing, and immune response of murine microglial cultures after stimulation with the Toll-like receptor (TLR) agonists tripalmitoyl-S-glyceryl-cysteine (TLR1/2), poly(I·C) (TLR3), lipopolysaccharide (TLR4), and CpG oligodeoxynucleotide (TLR9). Upon stimulation with high concentrations of TLR agonists, the release of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) was decreased in vitamin D-deficient compared to that in vitamin D-sufficient microglial cultures. Phagocytosis ofE. coliK1 after stimulation of microglial cells with high concentrations of TLR3, -4, and -9 agonists and intracellular killing ofE. coliK1 after stimulation with high concentrations of all TLR agonists were lower in vitamin D-deficient microglial cells than in the respective control cells. Our observations suggest that vitamin D deficiency may impair the resistance of the brain against bacterial infections.