bluuebunny/crossref_metadata_2025 huggingface dataset:
pmoA
Primers for Detection of Anaerobic Methanotrophs
Authors: Luesken Francisca A. , Zhu Baoli , van Alen Theo A. , Butler Margaret K. , Diaz Marina Rodriguez , Song Bongkeun , Op den Camp Huub J. M. , Jetten Mike S. M. , Ettwig Katharina F.
Published: April 2011

Published
pmoA
primers do not match the
pmoA
sequence of “
Candidatus
Methylomirabilis oxyfera,” a bacterium that performs nitrite-dependent anaerobic methane oxidation. Therefore, new
pmoA
primers for the detection of “
Ca
. Methylomirabilis oxyfera”-like methanotrophs were developed and successfully tested on freshwater samples from different habitats. These primers expand existing molecular tools for the study of methanotrophs in the environment.
Use of
1
H Nuclear Magnetic Resonance To Measure Intracellular Metabolite Levels during Growth and Asexual Sporulation in Neurospora crassa
Authors: Kim James D. , Kaiser Kayla , Larive Cynthia K. , Borkovich Katherine A.
Published: April 2011

Conidiation is an asexual sporulation pathway that is a response to adverse conditions and is the main mode of dispersal utilized by filamentous fungal pathogens for reestablishment in a more favorable environment. Heterotrimeric G proteins (consisting of α, β, and γ subunits) have been shown to regulate conidiation in diverse fungi. Previous work has demonstrated that all three of the Gα subunits in the filamentous fungus
Neurospora crassa
affect the accumulation of mass on poor carbon sources and that loss of
gna-3
leads to the most dramatic effects on conidiation. In this study, we used
1
H nuclear magnetic resonance (NMR) to profile the metabolome of
N. crassa
in extracts isolated from vegetative hyphae and conidia from cultures grown under conditions of high or low sucrose. We compared wild-type and Δ
gna-3
strains to determine whether lack of
gna-3
causes a significant difference in the global metabolite profile. The results demonstrate that the global metabolome of wild-type hyphae is influenced by carbon availability. The metabolome of the Δ
gna-3
strain cultured on both high and low sucrose is similar to that of the wild type grown on high sucrose, suggesting an overall defect in nutrient sensing in the mutant. However, analysis of individual metabolites revealed differences in wild-type and Δ
gna-3
strains cultured under conditions of low and high sucrose.
Regulation of Pathogenic Spore Germination by CgRac1 in the Fungal Plant Pathogen Colletotrichum gloeosporioides
Authors: Nesher Iris , Minz Anna , Kokkelink Leonie , Tudzynski Paul , Sharon Amir
Published: April 2011

Colletotrichum gloeosporioidesis a facultative plant pathogen: it can live as a saprophyte on dead organic matter or as a pathogen on a host plant. Different patterns of conidial germination have been recognized under saprophytic and pathogenic conditions, which also determine later development. Here we describe the role of CgRac1 in regulating pathogenic germination. The hallmark of pathogenic germination is unilateral formation of a single germ tube following the first cell division. However, transgenic strains expressing a constitutively active CgRac1 (CA-CgRac1) displayed simultaneous formation of two germ tubes, with nuclei continuing to divide in both cells after the first cell division. CA-CgRac1 also caused various other abnormalities, including difficulties in establishing and maintaining cell polarity, reduced conidial and hyphal adhesion, and formation of immature appressoria. Consequently, CA-CgRac1 isolates were completely nonpathogenic. Localization studies with cyan fluorescent protein (CFP)-CgRac1 fusion protein showed that the CgRac1 protein is abundant in conidia and in hyphal tips. Although the CFP signal was equally distributed in both cells of a germinating conidium, reactive oxygen species accumulated only in the cell that produced a germ tube, indicating that CgRac1 was active only in the germinating cell. Collectively, our results show that CgRac1 is a major regulator of asymmetric development and that it is involved in the regulation of both morphogenesis and nuclear division. Modification of CgRac1 activity disrupts the morphogenetic program and prevents fungal infection.
Genome Sequence of Strain TW25, a Novel Member of the Genus Ornithinibacillus in the Family Bacillaceae
Authors: Whon Tae Woong , Roh Seong Woon , Shin Na-Ri , Kim Min-Soo , Kim Young-Ok , Bae Jin-Woo
Published: April 2011

Ornithinibacillus
sp. strain TW25, belonging to the family
Bacillaceae
, was isolated from a dead ark clam during a mass mortality event. Here, the draft genome sequence of strain TW25 (3,843,870 bp, with a G+C content of 36.7%) is reported. This is the first
Ornithinibacillus
genome to be sequenced.
Genome Sequences of Mycoplasma alligatoris A21JP2
T
and Mycoplasma crocodyli MP145
T
Authors: Brown D. R. , Farmerie W. G. , May M. , Benders G. A. , Durkin A. S. , Hlavinka K. , Hostetler J. , Jackson J. , Johnson J. , Miller R. H. , Paralanov V. , Radune D. , Szczypinski B. , Glass J. I.
Published: April 2011

Mycoplasma alligatoris
and
Mycoplasma crocodyli
are closely related siblings, one being highly virulent and the other relatively attenuated. We compared their genomes to better understand the mechanisms and origins of
M. alligatoris
' remarkable virulence amid a clade of harmless or much less virulent species. Although its chromosome was refractory to closure,
M. alligatoris
differed most notably by its complement of sialidases and other genes of the
N
-acetylneuraminate scavenging and catabolism pathway.
Complete Genome Sequence of the Cellulolytic Thermophile Clostridium thermocellum DSM1313
Authors: Feinberg Lawrence , Foden Justine , Barrett Trisha , Davenport Karen Walston , Bruce David , Detter Chris , Tapia Roxanne , Han Cliff , Lapidus Alla , Lucas Susan , Cheng Jan-Fang , Pitluck Samuel , Woyke Tanja , Ivanova Natalia , Mikhailova Natalia , Land Miriam , Hauser Loren , Argyros D. Aaron , Goodwin Lynne , Hogsett David , Caiazza Nicky
Published: April 2011

Clostridium thermocellum
DSM1313 is a thermophilic, anaerobic bacterium with some of the highest rates of cellulose hydrolysis reported. The complete genome sequence reveals a suite of carbohydrate-active enzymes and demonstrates a level of diversity at the species level distinguishing it from the type strain ATCC 27405.
Genome Sequence of Streptomyces griseus Strain XylebKG-1, an Ambrosia Beetle-Associated Actinomycete
Authors: Grubbs Kirk J. , Biedermann Peter H. W. , Suen Garret , Adams Sandra M. , Moeller Joseph A. , Klassen Jonathan L. , Goodwin Lynne A. , Woyke Tanja , Munk A. Christine , Bruce David , Detter Chris , Tapia Roxanne , Han Cliff S. , Currie Cameron R.
Published: April 2011

Streptomyces griseus
strain XylebKG-1 is an insect-associated strain of the well-studied actinobacterial species
S. griseus
. Here, we present the genome of XylebKG-1 and discuss its similarity to the genome of
S. griseus
subsp. griseus NBRC13350. XylebKG-1 was isolated from the fungus-cultivating
Xyleborinus saxesenii
system. Given its similarity to free-living
S. griseus
subsp. griseus NBRC13350, comparative genomics will elucidate critical components of bacterial interactions with insects.
Complete Genome Sequence of Lactococcus lactis subsp.
lactis
CV56, a Probiotic Strain Isolated from the Vaginas of Healthy Women
Authors: Gao Yong , Lu Ying , Teng Kun-Ling , Chen Mei-Ling , Zheng Hua-Jun , Zhu Yong-Qiang , Zhong Jin
Published: April 2011

Lactic acid bacteria that exist in the urinogenital system play an important role in maintaining the health of the host. Here, we report the finished and annotated genome of a
Lactococcus
strain that was isolated from the vaginas of healthy women and shows probiotic properties, including nisin A production and adhesion to vaginal epithelial cells.
Genome-Wide Identification of Transcription Start Sites Yields a Novel Thermosensing RNA and New Cyclic AMP Receptor Protein-Regulated Genes in Escherichia coli
Authors: Raghavan Rahul , Sage Alan , Ochman Howard
Published: April 2011

Intergenic regions often contain regulatory elements that control the expression of flanking genes. Using a deep-sequencing approach, we identified numerous new transcription start sites in
Escherichia coli
, yielding a new thermosensing regulatory RNA and seven genes previously unknown to be under the control of the global regulator CRP.
Role of Rbp1 in the Acquired Chill-Light Tolerance of Cyanobacteria
Authors: Tan Xiaoming , Zhu Tao , Shen Si , Yin Chuntao , Gao Hong , Xu Xudong
Published: April 2011

Synechocystis
sp. strain PCC 6803 cultured at 30°C losses viability quickly under chill (5°C)-light stress but becomes highly tolerant to the stress after conditioning at 15°C (Y. Yang, C. Yin, W. Li, and X. Xu, J. Bacteriol.
190:
1554–1560, 2008). Hypothetically, certain factors induced during preconditioning are involved in acquisition of chill-light tolerance. In this study, Rbp1 (RNA-binding protein 1) rather than Rbp2 was found to be accumulated during preconditioning, and the accumulation of Rbp1 was correlated with the increase of chill-light tolerance. Inactivation of its encoding gene
rbp1
led to a great reduction in the acquired chill-light tolerance, while ectopic expression of
rbp1
enabled the cyanobacterium to survive the chill-light stress without preconditioning. Microarray analyses suggested that the Rbp1-dependent chill-light tolerance may not be based on its influence on mRNA abundance of certain genes. Similarly to that in
Synechocystis
, the Rbp1 homologue(s) can be accumulated in
Microcystis
cells collected from a subtropic lake in low-temperature seasons. Rbp1 is the first factor shown to be both accumulated early during preconditioning and directly involved in development of chill-light tolerance in
Synechocystis
. Its accumulation may greatly enhance the overwintering capability in certain groups of cyanobacteria.
The health paradox of occupational and leisure-time physical activity
Authors: Holtermann A , Hansen J V , Burr H , Søgaard K , Sjøgaard G
Published: April 2011

Background

Occupational and leisure-time physical activity are considered to provide similar health benefits. The authors tested this hypothesis.

Methods

A representative sample of Danish employees (n=7144, 52% females) reported levels of occupational and leisure-time physical activity in 2005. Long-term sickness absence (LTSA) spells of ≥3 consecutive weeks were retrieved from a social-transfer payment register from 2005 to 2007.

Results

341 men and 620 females experienced a spell of LTSA during the period. Cox analyses adjusted for age, gender, smoking, alcohol, body mass index, chronic disease, social support from immediate superior, emotional demands, social class and occupational or leisure-time physical activity showed a decreased risk for LTSA among workers with moderate (HR 0.85, CI 0.72 to 1.01) and high (HR 0.77, CI 0.62 to 0.95) leisure-time physical activity in reference to those with low leisure-time physical activity. In contrast, an increased risk for LTSA was shown among workers with moderate (HR 1.59, CI 1.35 to 1.88) and high (HR 1.84, CI 1.55 to 2.18) occupational physical activity referencing those with low occupational physical activity.

Conclusion

The hypothesis was rejected. In a dose–response manner, occupational physical activity increased the risk for LTSA, while leisure-time physical activity decreased the risk for LTSA. The findings indicate opposing effects of occupational and leisure-time physical activity on global health.
Use of abbreviations by healthcare professionals: what is the way forward?
Authors: Sinha S , McDermott F , Srinivas G , Houghton P W J
Published: April 2011

Objective

To assess the understanding of commonly used abbreviations in the medical records among healthcare professionals.

Methods

A selection of abbreviations from surgical inpatient admissions (gathered over a 10 day period in October 2008), in the form of a standard questionnaire, was shown to different members of a multidisciplinary team to examine interpretation and knowledge.

Results

209 questionnaires were analysed. The average correct response was 43%. Foundation Year 1 (F1) doctors scored the highest with 57% correct responses, whereas dieticians fared worst (20% correct). Among different abbreviations, NAD (91%) and SCBU (93%) were most often correctly answered, whereas CIC (3%) and STS (0.5%) were the most incorrectly answered. Certain abbreviations which are mostly used by nurses (eg, OTT) achieved a 75% correct response by them compared to only 11% by F1 and 10% by F2 doctors (p<0.001). Similarly, abbreviations such as COBH (p=0.025) and LUTS (p<0.001), although mostly correctly answered by junior doctors, were very poorly answered by nurses.

Conclusion

The majority of healthcare professionals have a very poor knowledge of commonly used abbreviations. Use of unambiguous and approved list of abbreviations is suggested in order to ensure good communication in patient care.
The social context of smoking cessation in China: an exploratory interview study
Authors: Zhang Jing-Yu , Chan Sophia Siu-Chee , Fong Daniel Yee-Tak , Malone Ruth E , Lam Tai-hing
Published: April 2011

Background

China has the largest population of smokers in the world. Little previous research has explored the cultural challenges in encouraging smoking cessation in China. This study aimed to explore and generate research questions about culturally distinctive beliefs and barriers to smoking cessation.

Methods

A convenience sample of 21 smokers and ex-smokers selected from a Guangzhou hospital smoking cessation clinic and medical ward was interviewed about experiences with quitting smoking. Data were analysed to elucidate culturally distinctive obstacles to cessation that may warrant further study.

Results

Three major obstacles to smoking cessation were identified: family and social influences, the myth that quitting smoking is dangerous to health and misinformation from health professionals.

Conclusions

This study suggests that smoking cessation in China is made more challenging by a social context in which family, friends and even health professionals may discourage it. However, these identified barriers and beliefs about smoking cessation need to be confirmed in larger, more representative studies in the future.
Luminescent Quantum Dots
Authors: Dukes Albert D. , McBride James R. , Rosenthal Sandra
Published: April 2011

Luminescent quantum dots have emerged over the last 25 years in a wide variety of research fields. This proceeding will discuss the synthesis of quantum dots, their structural properties, and ultrafast carrier dynamics. Additionally we will highlight the utilization of quantum dots in photovoltaics, solid-state lighting, and as fluorescent biological probes.
Bringing Silicon to Light: Luminescence in Silicon Nanostructures
Authors: Lockwood D. J.
Published: April 2011

The many and diverse approaches to materials science problems have greatly enhanced our ability in recent times to engineer the physical properties of semiconductors. Silicon, of all semiconductors, underpins nearly all microelectronics today and will continue to do so for some time to come. However, in optoelectronics and, more recently, in photonics, the severe disadvantage of an indirect band gap has limited the application of elemental silicon. Here we review a number of diverse approaches to engineering efficient light emission in silicon nanostructures. These different approaches are placed in context and their prospects are assessed for applications in silicon-based photonics.
Eu2+ Doped Calcium Chlorosilicate Phosphors: Polymorphism and Luminescence Properties
Authors: Karkada Nagaveni , Porob Digamber G. , Kumar Prasanth , Setlur Anant
Published: April 2011

In this paper, we discuss synthesis, polymorphism and luminescence properties of Eu2+ activated calcium chlorosilicate, (Ca3SiO4Cl2). Two different phases were found, one obtained at 800oC that shows emission peak at 525nm, and a higher temperature phase obtained at 1000oC with emission peak at 620 nm. Though the crystal structure of these two phases is very similar, their luminescence showed distinct green and orange emissions under 405nm excitation. Moreover, the thermal stability of these two phases are also distinctly different, low temperature phase was found to be less thermally stable (20% drop at 150oC) compared to the high temperature phase (4% drop at 150oC).
Combustion Synthesis and Photoluminescence Characteristics of SrY1.7B0.3O4: Eu Nanoparticles
Authors: Khatkar Satyender P. , Taxak Vinod B. , Sangwan Dayawati , Kumar Mukesh , Han Sang-Do
Published: April 2011

A novel red light emitting nano-sized Eu3+ doped SrY1.7B0.3O4 phosphor were synthesized by combustion method using urea as a fuel. Comparing with traditional material processing techniques, combustion method is a relatively simple method. The advantages of low temperature solution base process have been exploited to produce SrY1.7B0.3O4:Eu nanoparticles. The nano crystals obtained through combustion method was characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD) technique and photoluminescence (PL) spectra. This red emission has been assigned to the transition [5D0 →7F2] at 612 nm of Eu3+ ions. In addition the dependence of the luminescence intensity on Eu3+ ions concentrations and effect of heat treatment on the particle size of the nanocrystals have also been discussed. The present work reports to achieve the homogenous incorporation of dopants and large scale productions of the nanophosphor in a short interval of time. The particle size of the nanocrystals was found to be in the range of 30-40nm.
(Luminescence and Display Materials Division Centennial Outstanding Achievement Award) Band Gap Luminescence from Nanometer Thick Si/SiO2 Quantum Wells
Authors: Lockwood D. J.
Published: April 2011

In opto-electronics and photonics, the severe disadvantage of an indirect band gap has limited the application of elemental silicon. Amongst a number of diverse approaches to engineering efficient light emission in silicon nanostructures, one system that has received considerable attention has been Si/SiO2 quantum wells. Engineering such structures has not been easy, because to observe the desired quantum confinement effects, the quantum well thickness has to be less than 5 nm. Nevertheless, such ultra thin structures have now been produced by a variety of techniques. The SiO2 layers are amorphous, but the silicon layers can range from amorphous through nanocrystalline to single-crystal form. The fundamental band gap of the quantum wells has been measured primarily by optical techniques and strong confinement effects have been observed. A number of theories based primarily on ab initio approaches have been developed to explain these results with varying degrees of success. A detailed comparison is made between theoretical and experimental determinations of the band gap in Si/SiO2 quantum wells.
Effect of dietary omega-3 fatty acids on the heart rate and the heart rate variability responses to myocardial ischemia or submaximal exercise
Authors: Billman George E. , Harris William S.
Published: April 2011

The consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs) has been reported to decrease resting heart rate (HR) and increase heart rate variability (HRV). However, the effects of n-3 PUFAs on these variables in response to a physiological stress (e.g., exercise or acute myocardial ischemia), particularly in postmyocardial infarction (MI) patients, are unknown. Therefore, HR and HRV (high frequency and total R-R interval variability) were evaluated at rest, during submaximal exercise, and during a 2-min coronary artery occlusion at rest and before and 3 mo after n-3 PUFA treatment in dogs with healed MI ( n = 59). The dogs were randomly assigned to either placebo (1 g/day corn oil, n = 19) or n-3 PUFA supplement (docosahexaenoic acid + eicosapentaenoic acid ethyl esters; 1 g/day, n = 6; 2 g/day, n = 12; or 4 g/day, n = 22) groups. The treatment elicited significant ( P < 0.01) dose-dependent increases in right atrial n-3 PUFA levels but dose-independent reductions in resting HR and increases in resting HRV. In contrast, n-3 PUFAs did not attenuate the large changes in HR or HRV induced by either the coronary occlusion or submaximal exercise. These data demonstrate that dietary n-3 PUFA decreased resting (i.e., preexercise or preocclusion) HR and increased resting HRV but did not alter the cardiac response to physiologic challenges.
Functional expression of P2X4 receptor in capillary endothelial cells of the cochlear spiral ligament and its role in regulating the capillary diameter
Authors: Wu T. , Dai M. , Shi X. R. , Jiang Z. G. , Nuttall A. L.
Published: April 2011

The cochlear lateral wall generates the endocochlear potential (EP), which creates a driving force for the hair cell transduction current and is essential for normal hearing. Blood flow at the cochlear lateral wall is critically important for maintaining the EP. The vulnerability of the EP to hypoxia suggests that the blood flow in the cochlear lateral wall is dynamically and precisely regulated to meet the changing metabolic needs of the cochlear lateral wall. It has been reported that ATP, an important extracellular signaling molecule, plays an essential role in regulating cochlear blood flow. However, the cellular mechanism underlying ATP-induced regional blood flow changes has not been investigated. In the current study, we demonstrate that 1) the P2X4 receptor is expressed in endothelial cells (ECs) of spiral ligament (SL) capillaries. 2) ATP elicits a characteristic current through P2X4 on ECs in a dose-dependent manner (EC50= 0.16 mM). The ATP current has a reversal potential at ∼0 mV; is inhibited by 5-(3-bromophenyl)-1,3-dihydro-2 H-benzofuro[3,2- e]-1,4-diazepin-2-one (5-BDBD), LaCl3, pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt hydrate (PPADS), and extracellular acidosis; and is less sensitive to α,β-methyleneadenosine 5′-triphosphate (α,β-MeATP) and 2′- and 3′- O-(4-benzoyl-benzoyl) adenosine 5′-triphosphate (BzATP). 3) ATP elicits a transient increase of intracellular Ca2+in ECs. 4) In accordance with the above in vitro findings, perilymphatic ATP (1 mM) caused dilation in SL capillaries in vivo by 11.5%. Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME), a nonselective inhibitor of nitric oxide synthase, or 5-BDBD, the specific P2X4 inhibitor, significantly blocked the dilation. These findings support our hypothesis that extracellular ATP regulates cochlear lateral blood flow through P2X4 activation in ECs.
Intrathecal PACAP-38 causes prolonged widespread sympathoexcitation via a spinally mediated mechanism and increases in basal metabolic rate in anesthetized rat
Authors: Inglott Melissa A. , Farnham Melissa M. J. , Pilowsky Paul M.
Published: April 2011

The rostral ventrolateral medulla differentially regulates sympathetic output to different vascular beds, possibly through the release of various neurotransmitters and peptides that may include pituitary adenylate cyclase-activating polypeptide (PACAP). An intrathecal administration of PACAP increases splanchnic sympathetic nerve activity and heart rate, but not mean arterial blood pressure. The mechanism behind this response is unknown but may be due to a differential control of sympathetic outflows. In this study we sought 1) to investigate whether intrathecal PACAP differentially affects sympathetic outflow, 2) to determine whether the intrathecal responses to PACAP are solely due to a spinally mediated mechanism, and 3) to determine whether intrathecal PACAP affects metabolic function. Experiments using urethane-anesthetized, vagotomized, ventilated, and paralyzed adult male Sprague-Dawley rats were conducted in this study. Intrathecal injections of PACAP-38 were given, and mean arterial pressure, heart rate, the activity of regional sympathetic nerves, end-tidal CO2, and core temperature were recorded. The novel findings of this study are that 1) intrathecal PACAP-38 causes a prolonged widespread sympathoexcitation in multiple sympathetic beds, 2) this widespread sympathoexcitation is mediated within the spinal cord itself since spinal transection does not abrogate the response, and 3) that intrathecal PACAP-38 increases basal metabolic rate. Therefore, we conclude that intrathecal PACAP acts in the spinal cord to cause a prolonged widespread sympathoexcitation and that PACAP also causes an increase in basal metabolic rate that includes an increase in brown adipose tissue thermogenesis in our rat preparation.
Inward remodeling of resistance arteries requires reactive oxygen species-dependent activation of matrix metalloproteinases
Authors: Martinez-Lemus Luis A. , Zhao Guiling , Galiñanes Edgar L. , Boone Matthew
Published: April 2011

Inward eutrophic remodeling is the most prevalent structural change of resistance arteries in hypertension. Sympathetic and angiotensin (ANG)-induced vasoconstriction has been associated with hypertension and with the production of matrix metalloproteinases (MMPs) and ROS. Therefore, we hypothesize that prolonged exposure to norepinephrine (NE) and ANG II induces arteriolar inward remodeling dependent on the activation of MMPs and the production of ROS. This hypothesis was tested on rat cremaster arterioles that were isolated, cannulated, pressurized, and exposed to either NE (10−5.5 mol/l) + ANG II (10−7 mol/l) or vehicle (control) for 4 h. The prolonged exposure to NE + ANG II induced inward remodeling, as evidenced by the reduced maximal arteriolar passive diameter observed after versus before exposure to the vasoconstrictor agonists. NE + ANG II also increased the arteriolar expression and activity of MMP-2 and the production of ROS as determined, respectively, by real-time RT-PCR, gel and in situ zymography, and the use of ROS-sensitive dyes with multiphoton microscopy. Inhibition of MMP activation (with GM-6001) or ROS production (with apocynin or tempol) prevented the NE + ANG II-induced inward remodeling. Inhibition of ROS production prevented the activation of MMPs and the remodeling process, whereas inhibition of MMP activation did not affect ROS production. These results indicate that prolonged stimulation of resistance arterioles with NE + ANG II induces a ROS-dependent activation of MMPs necessary for the development of arteriolar inward remodeling. These mechanisms may contribute to the structural narrowing of resistance vessels in hypertension.
Role of superoxide and thromboxane receptors in acute angiotensin II-induced vasoconstriction of rabbit vessels
Authors: Pfister Sandra L. , Nithipatikom Kasem , Campbell William B.
Published: April 2011

This study explored the hypothesis that a portion of angiotensin II-induced contractions is dependent on superoxide generation and release of a previously unidentified arachidonic acid metabolite that activates vascular smooth muscle thromboxane receptors. Treatment of rabbit aorta or mesentery artery with the thromboxane receptor antagonist SQ29548 (10 μM) reduced angiotensin II-induced contractions (maximal contraction in aorta; control vs. SQ29548: 134 ± 16 vs. 93 ± 10%). A subset of rabbits deficient in vascular thromboxane receptors also displayed decreased contractions to angiotensin II. The superoxide dismutase mimetic Tiron (30 mM) attenuated angiotensin II-induced contractions only in rabbits with functional vascular thromboxane receptors (maximal contraction in aorta; control vs. Tiron: 105 ± 5 vs. 69 ± 11%). Removal of the endothelium or treatment with a nitric oxide synthase inhibitor, nitro-l-arginine (30 μM) did not alter angiotensin II-induced contractions. Tiron and SQ29548 decreased angiotensin II-induced contractions in the denuded aortas by a similar percentage as that observed in intact vessels. The cyclooxygenase inhibitor indomethacin (10 μM) or thromboxane synthase inhibitor dazoxiben (10 μM) had no effect on angiotensin II-induced contractions indicating that the vasoconstrictor was not thromboxane. Angiotensin II increased the formation of a 15-series isoprostane. Isoprostanes are free radical-derived products of arachidonic acid. The unidentified isoprostane increased when vessels were incubated with the superoxide-generating system xanthine/xanthine oxidase. Pretreatment of rabbit aorta with the isoprostane isolated from aortic incubations enhanced angiotensin II-induced contractions. Results suggest the factor activating thromboxane receptors and contributing to angiotensin II vasoconstriction involves the superoxide-mediated generation of a 15-series isoprostane.
Myosin head orientation: a structural determinant for the Frank-Starling relationship
Authors: Farman Gerrie P. , Gore David , Allen Edward , Schoenfelt Kelly , Irving Thomas C. , de Tombe Pieter P.
Published: April 2011

The cellular mechanism underlying the Frank-Starling law of the heart is myofilament length-dependent activation. The mechanism(s) whereby sarcomeres detect changes in length and translate this into increased sensitivity to activating calcium has been elusive. Small-angle X-ray diffraction studies have revealed that the intact myofilament lattice undergoes numerous structural changes upon an increase in sarcomere length (SL): lattice spacing and the I1,1/I1,0 intensity ratio decreases, whereas the M3 meridional reflection intensity (IM3) increases, concomitant with increases in diastolic and systolic force. Using a short (∼10 ms) X-ray exposure just before electrical stimulation, we were able to obtain detailed structural information regarding the effects of external osmotic compression (with mannitol) and obtain SL on thin intact electrically stimulated isolated rat right ventricular trabeculae. We show that over the same incremental increases in SL, the relative changes in systolic force track more closely to the relative changes in myosin head orientation (as reported by IM3) than to the relative changes in lattice spacing. We conclude that myosin head orientation before activation determines myocardial sarcomere activation levels and that this may be the dominant mechanism for length-dependent activation.
Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis
Authors: Arnold Amy C. , Shaltout Hossam A. , Gilliam-Davis Shea , Kock Nancy D. , Diz Debra I.
Published: April 2011

The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II.
Interleukin-13 inhibits proliferation and enhances contractility of human airway smooth muscle cells without change in contractile phenotype
Authors: Risse Paul-André , Jo Taisuke , Suarez Fernando , Hirota Nobuaki , Tolloczko Barbara , Ferraro Pasquale , Grutter Peter , Martin James G.
Published: April 2011

IL-13 is an important mediator of allergen-induced airway hyperresponsiveness. This Th2 cytokine, produced by activated T cells, mast cells, and basophils, has been described to mediate a part of its effects independently of inflammation through a direct modulation of the airway smooth muscle (ASM). Previous studies demonstrated that IL-13 induces hyperresponsiveness in vivo and enhances calcium signaling in response to contractile agonists in vitro. We hypothesized that IL-13 drives human ASM cells (ASMC) to a procontractile phenotype. We evaluated ASM phenotype through the ability of the cell to proliferate, to contract, and to express contractile protein in response to IL-13. We found that IL-13 inhibits human ASMC proliferation (expression of Ki67 and bromodeoxyuridine incorporation) in response to serum, increasing the number of cells in G0/G1 phase and decreasing the number of cells in G2/M phases of the cell cycle. IL-13-induced inhibition of proliferation was not dependent on signal transducer and activator of transcription-6 but was IL-13Rα2 receptor dependent and associated with a decrease of Kruppel-like factor 5 expression. In parallel, IL-13 increased calcium signaling and the stiffening of human ASMC in response to 1 μM histamine, whereas the stiffening response to 30 mM KCl was unchanged. However, Western blot analysis showed unchanged levels of calponin, smooth muscle α-actin, vinculin, and myosin. We conclude that IL-13 inhibits proliferation via the IL-13Rα2 receptor and induces hypercontractility of human ASMC without change of the phenotypic markers of contractility.
Proteasome inhibition improves diaphragm function in an animal model for COPD
Authors: van Hees Hieronymus , Ottenheijm Coen , Ennen Leo , Linkels Marianne , Dekhuijzen Richard , Heunks Leo
Published: April 2011

Diaphragm muscle weakness in patients with chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality. Recent studies indicate that increased contractile protein degradation by the proteasome contributes to diaphragm weakness in patients with COPD. The aim of the present study was to investigate the effect of proteasome inhibition on diaphragm function and contractile protein concentration in an animal model for COPD. Elastase-induced emphysema in hamsters was used as an animal model for COPD; normal hamsters served as controls. Animals were either treated with the proteasome inhibitor Bortezomib (iv) or its vehicle saline. Nine months after induction of emphysema, specific force-generating capacity of diaphragm bundles was measured. Proteolytic activity of the proteasome was assayed spectrofluorometrically. Protein concentrations of proteasome, myosin, and actin were measured by means of Western blotting. Proteasome activity and concentration were significantly higher in the diaphragm of emphysematous hamsters than in normal hamsters. Bortezomib treatment reduced proteasome activity in the diaphragm of emphysematous and normal hamsters. Specific force-generating capacity and myosin concentration of the diaphragm were reduced by ∼25% in emphysematous hamsters compared with normal hamsters. Bortezomib treatment of emphysematous hamsters significantly increased diaphragm-specific force-generating capacity and completely restored myosin concentration. Actin concentration was not affected by emphysema, nor by bortezomib treatment. We conclude that treatment with a proteasome inhibitor improves contractile function of the diaphragm in emphysematous hamsters through restoration of myosin concentration. These findings implicate that the proteasome is a potential target of pharmacological intervention on diaphragm weakness in COPD.
Partial pneumonectomy of telomerase null mice carrying shortened telomeres initiates cell growth arrest resulting in a limited compensatory growth response
Authors: Jackson Sha-Ron , Lee Jooeun , Reddy Raghava , Williams Genevieve N. , Kikuchi Alexander , Freiberg Yael , Warburton David , Driscoll Barbara
Published: April 2011

Telomerase mutations and significantly shortened chromosomal telomeres have recently been implicated in human lung pathologies. Natural telomere shortening is an inevitable consequence of aging, which is also a risk factor for development of lung disease. However, the impact of shortened telomeres and telomerase dysfunction on the ability of lung cells to respond to significant challenge is still largely unknown. We have previously shown that lungs of late generation, telomerase null B6.Cg- Terc tm1Rdp mice feature alveolar simplification and chronic stress signaling at baseline, a phenocopy of aged lung. To determine the role telomerase plays when the lung is challenged, B6.Cg- Terc tm1Rdp mice carrying shortened telomeres and wild-type controls were subjected to partial pneumonectomy. We found that telomerase activity was strongly induced in alveolar epithelial type 2 cells (AEC2) of the remaining lung immediately following surgery. Eighty-six percent of wild-type animals survived the procedure and exhibited a burst of early compensatory growth marked by upregulation of proliferation, stress response, and DNA repair pathways in AEC2. In B6.Cg- Terc tm1Rdp mice carrying shortened telomeres, response to pneumonectomy was characterized by decreased survival, diminished compensatory lung growth, attenuated distal lung progenitor cell response, persistent DNA damage, and cell growth arrest. Overall, survival correlated strongly with telomere length. We conclude that functional telomerase and properly maintained telomeres play key roles in both long-term survival and the early phase of compensatory lung growth following partial pneumonectomy.
Rhinovirus infection induces extracellular matrix protein deposition in asthmatic and nonasthmatic airway smooth muscle cells
Authors: Kuo Curtis , Lim Sam , King Nicholas J. C. , Johnston Sebastian L. , Burgess Janette K. , Black Judith L. , Oliver Brian G.
Published: April 2011

Airway remodeling, which includes increases in the extracellular matrix (ECM), is a characteristic feature of asthma and is correlated to disease severity. Rhinovirus (RV) infections are associated with increased risk of asthma development in young children and are the most common cause of asthma exacerbations. We examined whether viral infections can increase ECM deposition and whether this increased ECM modulates cell proliferation and migration. RV infection of nonasthmatic airway smooth muscle (ASM) cells significantly increased the deposition of fibronectin (40% increase, n = 12) and perlecan (80% increase, n = 14), while infection of asthmatic ASM cells significantly increased fibronectin (75% increase, n = 9) and collagen IV (15% increase, n = 9). We then treated the ASM cells with the Toll-like receptor (TLR) agonists polyinosinic:polycytidylic acid, imiquimod, and pure RV RNA and were able to show that the mechanism through which RV induced ECM deposition was via the activation of TLR3 and TLR7/8. Finally, we assessed whether the virus-induced ECM was bioactive by measuring the amount of migration and proliferation of virus-naive cells that seeded onto the ECM. Basically, ECM from asthmatic ASM cells induced twofold greater migration of virus-naive ASM cells than ECM from nonasthmatic ASM cells, and these rates of migration were further increased on RV-modulated ECM. Increased migration on the RV-modulated ECM was not due to increased cell proliferation, as RV-modulated ECM decreased the proliferation of virus-naive cells. Our results suggest that viruses may contribute to airway remodeling through increased ECM deposition, which in turn may contribute to increased ASM mass via increased cell migration.
Bortezomib Primes Neuroblastoma Cells for TRAIL-Induced Apoptosis by Linking the Death Receptor to the Mitochondrial Pathway
Authors: Naumann Ivonne , Kappler Roland , von Schweinitz Dietrich , Debatin Klaus-Michael , Fulda Simone
Published: April 2011

Purpose: Searching for novel strategies to modulate apoptosis in neuroblastoma, we investigated the potential of the proteasome inhibitor bortezomib.

Experimental Design: The effect of bortezomib on TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis signaling pathways was analyzed in neuroblastoma cell lines, primary neuroblastoma cultures, and in an in vivo model.

Results: Bortezomib synergistically cooperates with TRAIL to induce apoptosis and to reduce colony formation of neuroblastoma cells (combination index: 0.5). Mechanistic studies reveal that bortezomib profoundly enhances TRAIL-induced cleavage of Bid into tBid, accumulation of tBid in the cytosol, and its insertion into mitochondrial membranes, pointing to a concerted effect on Bid cleavage (TRAIL) and stabilization of tBid (bortezomib), which links the death receptor to the mitochondrial pathway. In addition, bortezomib increases expression of p53 and Noxa. All these changes lead to increased activation of Bax and Bak, loss of the mitochondrial membrane potential, cytochrome c release, caspase activation, and caspase-dependent apoptosis on treatment with bortezomib and TRAIL. Knockdown of Bid, Noxa, or p53 significantly delays the kinetic of bortezomib- and TRAIL-induced apoptosis, whereas it does not confer long-term protection. By comparison, overexpression of Bcl-2, which simultaneously antagonizes tBid and p53, significantly inhibits bortezomib- and TRAIL-induced apoptosis and even rescues clonogenic survival. Importantly, bortezomib and TRAIL act in concert to trigger apoptosis and to suppress tumor growth in patient-derived primary neuroblastoma cells and in an in vivo model of neuroblastoma.

Conclusions: Bortezomib represents a promising new approach to prime neuroblastoma cells toward TRAIL, which warrants further investigation. Clin Cancer Res; 17(10); 3204–18. ©2011 AACR.
Phase I Study of GSK461364, a Specific and Competitive Polo-like Kinase 1 Inhibitor, in Patients with Advanced Solid Malignancies
Authors: Olmos David , Barker Douglas , Sharma Rohini , Brunetto Andre T. , Yap Timothy A. , Taegtmeyer Anne B. , Barriuso Jorge , Medani Hanine , Degenhardt Yan Y. , Allred Alicia J. , Smith Deborah A. , Murray Sharon C. , Lampkin Thomas A. , Dar Mohammed M. , Wilson Richard , de Bono Johann S. , Blagden Sarah P.
Published: April 2011

Purpose: GSK461364 is an ATP-competitive inhibitor of polo-like kinase 1 (Plk1). A phase I study of two schedules of intravenous GSK461364 was conducted.

Experimental Design: GSK461364 was administered in escalating doses to patients with solid malignancies by two schedules, either on days 1, 8, and 15 of 28-day cycles (schedule A) or on days 1, 2, 8, 9, 15, and 16 of 28-day cycles (schedule B). Assessments included pharmacokinetic and pharmacodynamic profiles, as well as marker expression studies in pretreatment tumor biopsies.

Results: Forty patients received GSK461364: 23 patients in schedule A and 17 in schedule B. Dose-limiting toxicities (DLT) in schedule A at 300 mg (2 of 7 patients) and 225 mg (1 of 8 patients) cohorts included grade 4 neutropenia and/or grade 3–4 thrombocytopenia. In schedule B, DLTs of grade 4 pulmonary emboli and grade 4 neutropenia occurred at 7 or more days at 100 mg dose level. Venous thrombotic emboli (VTE) and myelosuppression were the most common grade 3–4, drug-related events. Pharmacokinetic data indicated that AUC (area under the curve) and Cmax (maximum concentration) were proportional across doses, with a half-life of 9 to 13 hours. Pharmacodynamic studies in circulating tumor cells revealed an increase in phosphorylated histone H3 (pHH3) following drug administration. A best response of prolonged stable disease of more than 16 weeks occurred in 6 (15%) patients, including 4 esophageal cancer patients. Those with prolonged stable disease had greater expression of Ki-67, pHH3, and Plk1 in archived tumor biopsies.

Conclusions: The final recommended phase II dose for GSK461364 was 225 mg administered intravenously in schedule A. Because of the high incidence (20%) of VTE, for further clinical evaluation, GSK461364 should involve coadministration of prophylactic anticoagulation. Clin Cancer Res; 17(10); 3420–30. ©2011 AACR.
Progesterone Receptor Isoform-Specific Promoter Methylation: Association ofPRAPromoter Methylation with Worse Outcome in Breast Cancer Patients
Authors: Pathiraja Thushangi N. , Shetty Priya B. , Jelinek Jaroslav , He Rong , Hartmaier Ryan , Margossian Astrid L. , Hilsenbeck Susan G. , Issa Jean-Pierre J. , Oesterreich Steffi
Published: April 2011

Purpose: ERα and PR levels are critical determinants for breast cancer prognosis and response to endocrine therapy. Although PR is known to be silenced by methylation of its promoter, few studies have correlated methylation with PR levels and outcome in breast cancer. There is only one previous small study comparing methylation of the two PR isoforms, PRA and PRB, which are expressed from different promoters, and finally, there is no prior knowledge of associations between isoform-specific methylation and outcome.

Experimental Design: We conducted a cohort-based study to test for associations between PRA and PRB methylation, expression, and clinical outcome in tamoxifen-treated patients (n = 500), and in patients who underwent surgery only (n = 500). Methylation and PR levels were measured by bisulfite pyrosequencing and ligand-binding assay, respectively.

Results: Low PR levels were significantly associated with worse outcome in all patients. PRA and PRB promoters were methylated in 9.6% and 14.1% of the breast tumors, respectively. The majority (74%) of PR-negative tumors were not methylated despite the significant inverse correlation of methylation and PR levels. PRA methylation was significantly associated with PRB methylation, although a subset of tumors had PRA only (3.9%) or PRB only (8.3%) methylated. Methylation of PRA, but not PRB was significantly associated with worse outcome in the tamoxifen-treated group.

Conclusions: Mechanisms other than promoter methylation may be more dominant for loss of PR. Isoform-specific methylation events suggest independent regulation of PRA and PRB. Finally, this article shows for the first time that PRA methylation plays a unique role in tamoxifen-resistant breast cancer. Clin Cancer Res; 17(12); 4177–86. ©2011 AACR.