bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of in Situ Estrogen Synthesis by Proline-, Glutamic Acid-, and Leucine-Rich Protein-1: Potential Estrogen Receptor Autocrine Signaling Loop in Breast Cancer Cells
Authors: Rajhans Rajib , Nair Hareesh B. , Nair Sujit S. , Cortez Valerie , Ikuko Kijima , Kirma Nameer B. , Zhou Dujin , Holden Alan E. , Brann Darrell W , Chen Shiuan , Tekmal Rajeshwar Rao , Vadlamudi Ratna K. 
Published: December 2007

AbstractIn situ estrogen synthesis is implicated in tumor cell proliferation through autocrine or paracrine mechanisms especially in postmenopausal women. Several recent studies demonstrated activity of aromatase, an enzyme that plays a critical role in estrogen synthesis in breast tumors. Proline-, glutamic acid-, and leucine-rich protein-1 (PELP1/MNAR) is an estrogen receptor (ER) coregulator, and its expression is deregulated in breast tumors. In this study, we examined whether PELP1 promotes tumor growth by promoting local estrogen synthesis using breast cancer cells (MCF7) that stably overexpress PELP1. Immunohistochemistry revealed increased aromatase expression in MCF7-PELP1-induced xenograft tumors. Real-time PCR analysis showed enhanced activation of the aromatase promoter in MCF7-PELP1 clones compared with MCF7 cells. Using a tritiated-water release assay, we demonstrated that MCF7-PELP1 clones exhibit increased aromatase activity compared with control MCF-7 cells. PELP1 deregulation uniquely up-regulated aromatase expression via activation of aromatase promoter I.3/II, and growth factor signaling enhanced PELP1 activation of aromatase. PELP1-mediated induction of aromatase requires functional Src and phosphatidylinositol-3-kinase pathways. Mechanistic studies revealed that PELP1 interactions with ER-related receptor-α and proline-rich nuclear receptor coregulatory protein 2 lead to activation of aromatase. Immunohistochemistry analysis of breast tumor array showed increased expression of aromatase in ductal carcinoma in situ and node-positive tumors compared with no or weak expression in normal breast tissue. Fifty-four percent (n = 79) of PELP1-overexpressing tumors also overexpressed aromatase compared with 36% (n = 47) in PELP1 low-expressing tumors. Our results suggest that PELP1 regulation of aromatase represents a novel mechanism for in situ estrogen synthesis leading to tumor proliferation by autocrine loop and open a new avenue for ablating local aromatase activity in breast tumors.
Glucocorticoid/Glucocorticoid Receptor Inhibition of Surfactant Protein-A (SP-A) Gene Expression in Lung Type II Cells Is Mediated by Repressive Changes in Histone Modification at the SP-A Promoter
Authors: Islam Kazi Nazrul , Mendelson Carole R. 
Published: December 2007

AbstractSurfactant protein-A (SP-A) gene expression in human fetal lung type II cells is stimulated by cAMP and IL-1 and is inhibited by glucocorticoids. cAMP/IL-1 stimulation of SP-A expression is mediated by increased binding of thyroid transcription factor-1 and nuclear factor (NF)-κB to the TTF-1-binding element (TBE) in the SP-A promoter. This is associated with decreased expression of histone deacetylases (HDACs), increased recruitment of coactivators, and enhanced acetylation of histone H3 (K9,14) at the TBE. In the present study, endogenous glucocorticoid receptor (GR) was found to interact with thyroid transcription factor-1 and NF-κB p65 at the TBE. GR knockdown enhanced SP-A expression in type II cells cultured in serum-free medium, suggesting a ligand-independent inhibitory role of endogenous GR. Furthermore, use of chromatin immunoprecipitation revealed that dexamethasone (Dex) treatment of fetal lung type II cells increased recruitment of endogenous GR and HDACs-1 and -2 and blocked cAMP-induced binding of inhibitor of κB kinase-α (IKKα) to the TBE region. Accordingly, Dex reduced basal and blocked cAMP-stimulated levels of acetylated (K9,14) and phosphorylated (S10) histone H3 at the TBE. Dex also increased TBE binding of dimethylated histone H3 (K9) and of heterochromatin protein 1α. Thus, Dex increases interaction of GR with the complex of proteins at the TBE. This facilitates recruitment of HDACs and causes a local decline in basal and cAMP-induced histone H3 phosphorylation and acetylation and an associated increase in H3-K9 dimethylation and binding of heterochromatin protein 1α. Collectively, these events may culminate in the closing of chromatin structure surrounding the SP-A gene and inhibition of its transcription.
Energy saving processes in huddling emperor penguins: from experiments to theory
Authors: Gilbert Caroline , Blanc Stéphane , Le Maho Yvon , Ancel André 
Published: December 2007

SUMMARYThis paper investigates the energy savings of male emperor penguins Aptenodytes forsteri linked to their huddling behaviour, the key factor that allows them to assume their incubating task while undergoing a long fast. Drawing on new studies by our team, this review examines the energetic benefits accrued from huddling and estimates the respective contributions of wind protection, exposure to mild ambient temperatures,reduction in cold-exposed body surfaces and body temperature adjustments in these energy savings. The metabolic rate of `loosely grouped' birds(restrained in small groups of 5–10 individuals, which are unable to huddle effectively) is reduced by 39% compared to metabolic rate of `isolated'birds, with 32% of these energetic benefits due to wind protection. In addition, metabolic rate of `free-ranging' emperors, i.e. able to move freely and to huddle, is on average 21% lower than that of `loosely grouped' birds. Exposure to mild ambient temperatures within the groups and reduction in cold-exposed body surfaces while huddling, though overestimated, would represent a 38% metabolic reduction. About two thirds of metabolic lowering is attributable to the reduction in cold-exposed body surfaces and one third to the mild microclimate created within the groups. Moreover, body temperature adjustments contribute to these energetic benefits: maintaining body temperatures 1°C lower would represent a 7–17% reduction in energy expenditure. These processes, linked together, explain how huddling emperors save energy and maintain a constant body temperature, which ensures a successful incubation in the midst of the austral winter.
Impaired escape flight ability in butterflies due to low flight muscle ratio prior to hibernation
Authors: Almbro Maria , Kullberg Cecilia 
Published: December 2007

SUMMARY
For an animal to escape an attacking predator, speed and manoeuvrability are likely to be crucial factors. Previous studies on reptiles and birds have revealed that gaining weight, due to for instance egg load or lipid accumulation, leads to impaired escape ability and possibly increases the risk of being caught by predators. Here we tested whether the flight performance of an insect, the small tortoiseshell butterfly (Aglais urticae), is affected by variations in body mass due to feeding by comparing flight performance parameters between individuals that (i) took flight spontaneously or after being subjected to a simulated predator attack and (ii) varied in flight muscle ratio (FMR: thorax mass/total body mass). The results show that butterflies that were subjected to a simulated predator attack flew at higher velocities and straighter than butterflies that were allowed to take off spontaneously. Furthermore, our study suggests, for the first time, that butterflies may experience impaired escape ability after feeding, which directly leads to a decrease in FMR; a reduction from 0.5 to 0.3 reduced escape flight velocity by about 37% at 0.5 m from the start. Finally, this study shows that FMR affects take-off angle and sinuosity, with steeper angles and more turning in butterflies with low FMR.
A cumulative feeding threshold required for vitellogenesis can be obviated with juvenile hormone treatment in lubber grasshoppers
Authors: Fronstin R. B. , Hatle J. D. 
Published: December 2007

SUMMARYDevelopmental thresholds can ensure that an adequate condition has been attained to proceed through major transitions (e.g. initiation of reproduction, metamorphosis). Nutrition is critical to attaining most thresholds, because it is needed for both growth and storage. Attaining a threshold typically stimulates the release of hormones that commit the animal to the developmental transition, yet the relationships between the nutrition needed for developmental thresholds and these endocrine signals are poorly understood. Lubber grasshoppers require a cumulative feeding threshold to initiate vitellogenesis and potentially commit to oviposition. We tested the relative roles of the nutritional threshold and the major gonadotropin(juvenile hormone; JH) in initiating vitellogenesis and committing to oviposition. The source of JH was removed from all females, and then JH analog was applied after different amounts of feeding. Threshold feeding was not required to initiate vitellogenesis, suggesting that sub-threshold grasshoppers are competent to respond to JH. Further, sub-threshold grasshoppers went on to oviposit earlier than supra-threshold grasshoppers treated with JH at the same time. Hence, threshold feeding is required only to cause the production and release of JH. At the same time, we also found that individuals that were restored with JH late in life tended to favor current reproduction, at the expense of future reproduction. Both time to oviposition and vitellogenin profiles were consistent with this developmental allocation. Taken together, our results suggest that lubber grasshoppers adjust reproductive tactics primarily in response to nutrition (which only serves to release JH) and secondarily in response to age.
Jamming avoidance response of big brown bats in target detection
Authors: Bates Mary E. , Stamper Sarah A. , Simmons James A. 
Published: December 2007

SUMMARYWhen searching for prey, big brown bats (Eptesicus fuscus) enhance the range of their sonar by concentrating more energy in the nearly constant-frequency (CF) tail portion of their frequency-modulated (FM) sweeps. We hypothesize that this portion of their signals may be vulnerable to interference from conspecifics using the same frequencies in their own emissions. To determine how bats modify their signals when confronted with an interfering stimulus, we compared the echolocation calls of bats when a CF jamming tone was on and off. The bats performed a two-alternative forced-choice detection task in the laboratory that required the use of echolocation. All three bats shifted the tail-end CF component of their emitted frequency bidirectionally away from the CF jamming stimulus only when the jamming frequency was within 2–3 kHz of the preferred baseline frequency of the bat. The duration of their emissions did not differ between the jamming and no-jamming trials. The jamming avoidance response of bats may serve to avoid masking or interference in a narrow range of frequencies important for target detection.
A new method to quantify prey acquisition in diving seabirds using wing stroke frequency
Authors: Sato Katsufumi , Daunt Francis , Watanuki Yutaka , Takahashi Akinori , Wanless Sarah 
Published: December 2007

SUMMARY
To understand the foraging strategies of free-ranging diving animals, time series information on both foraging effort and foraging success is essential. Theory suggests that wing stroke frequency for aerial flight should be higher in heavier birds. Based on this premise, we developed a new methodology using animal-borne accelerometers to estimate fine-scale temporal changes in body mass of a pursuit-diving, piscivorous seabird, the European shag, Phalacrocorax aristotelis. We hypothesized that variations in body mass determined from changes in wing stroke frequency before and after a series of dives would be related to the amount of prey captured. The estimated net gain in body mass during a foraging trip was highly variable, ranging from–30 to 260 g, values that were extremely similar to food loads obtained from shags on the Isle of May in previous years using water-offloading and nest balances. Load sizes estimated using the wing stroke method were strongly and positively related to both cumulative flight time and return flight time. At the trip level, load size was unrelated to cumulative dive bout duration and the total amount of time spent underwater. However, highly significant relationships were apparent at the individual bout level, with birds showing bigger mass gains following longer dive bouts. Results from this study are therefore extremely encouraging and suggest that changes in body mass determined from changes in wing stroke frequency may provide a reliable method of obtaining short- to medium-term information on foraging effort and success of diving seabirds.
Differential actions of diuretic factors on the Malpighian tubules ofRhodnius prolixus
Authors: Donini Andrew , O'Donnell Michael J. , Orchard Ian 
Published: December 2007

SUMMARYThe effects of corticotropin-releasing factor (CRF)-related (ZooneDH),calcitonin (CT)-related (RhoprDH31) and kinin-related (leucokinin I) peptides on the ion composition of fluid secreted by upper Rhodnius prolixus Malpighian tubules and on KCl reabsorption by the lower tubules were assessed. ZooneDH stimulated fluid secretion while increasing the[Na+] of secreted fluid at the expense of [K+]. Upper tubules responded to ZooneDH with a characteristic triphasic change in the transepithelial potential (TEP), reminiscent of the response to 5-hydroxytryptamine (5HT). RhoprDH31 produced a small (∼9 mV)lumen-positive shift in TEP of the upper tubule but had no effect on the rate of fluid secretion or ion composition of the secreted fluid. In contrast to 5HT, both peptides failed to activate KCl reabsorption by the lower tubule. Leucokinin I had no effect on the ion composition of fluid secreted by whole or upper Malpighian tubules. We propose that: (1) 5HT and a native CRF-related peptide similar to ZooneDH activate the same second messenger systems and ion transporters in the upper tubule cells; (2) CRF-related peptide is utilized to maintain high rates of fluid secretion during the post-feeding diuresis and is additionally used at times when KCl reabsorption is unnecessary or detrimental. The differential actions of multiple diuretic factors allows for intricate control of ionic and osmotic balance in R. prolixus.
Morphological and mechanical determinants of bite force in bats: do muscles matter?
Authors: Herrel Anthony , De Smet Ann , Aguirre Luis F. , Aerts Peter 
Published: December 2007

SUMMARYBats are one of the most diverse groups of mammals and have radiated into a wide variety of trophic niches. Accordingly, the cranial structure in bats is unusually variable among mammals and thought to reflect specializations for feeding and echolocation. However, recent analyses of cranial structure,feeding behavior and bite force across a wide range of bats suggest that correlations between morphology and performance and/or ecology are not as clearcut as previously thought. For example, most of the variation in bite force across a wide range of phyllostomid bats was explained by differences in body size rather than specific cranial traits. However, remarkably little is known about the muscular components that are responsible for generating the actual bite forces. We have tested which aspects of the cranial muscular system are good predictors of bite force across a wide range of species using a modeling approach. Model calculations of bite force show good correspondence with in vivo data suggesting that they can be used to estimate performance of the cranial system. Moreover, our data show that bite force is strikingly well explained by differences in temporalis muscle mass, temporalis fiber length and masseter muscle mass. Moreover, our data show that evolutionary changes in bite force capacity in bats are associated with evolutionary changes in relative m. temporalis mass and absolute skull length.
TheDrosophilamuscle LIM protein, Mlp84B, is essential for cardiac function
Authors: Mery Annabelle , Taghli-Lamallem Ouarda , Clark Kathleen A. , Beckerle Mary C. , Wu Xiushan , Ocorr Karen , Bodmer Rolf 
Published: December 2007

SUMMARYMuscle LIM protein (MLP) is a cytoskeletal protein located at the Z-disc of sarcomeres. Mutations in the human MLP gene are associated with hypertrophic and dilated cardiomyopathy. MLP has been proposed to be a key player in the stretch-sensing response, but the molecular mechanisms underlying its function in normal and diseased cardiac muscle have not been established. A Drosophila homolog, Mlp84B, displays a similar subcellular localization at the Z-disc of sarcomeres throughout development and in the adult, suggesting Drosophila as a model to study MLP function. Here we employed genetic ablation and cardiac-specific RNA interference (RNAi) knockdown of mlp84B to investigate its role in heart function. We found that Mlp84B-deficient or heart-specific RNAi knockdown flies exhibit diastolic interval prolongation, heart rhythm abnormalities and a reduced lifespan, while showing no obvious structural phenotype. Our data demonstrate that Mlp84B is essential for normal cardiac function and establish the Drosophila model for the investigation of the mechanisms connecting defective cardiac Z-disc components to the development of cardiomyopathy.
Development partly determines the aerobic performance of adult deer mice,Peromyscus maniculatus
Authors: Russell Gregory A. , Rezende Enrico L. , Hammond Kimberly A. 
Published: December 2007

SUMMARYPrevious studies suggest that genetic factors and acclimation can account for differences in aerobic performance(V̇O2max) between high and low altitude populations of small mammals. However, it remains unclear to what extent development at different oxygen partial pressures(PO2) can affect aerobic performance during adulthood. Here we compared the effects of development at contrasting altitudes versus effects of acclimation during adulthood on V̇O2max. Two groups of deer mice were born and raised for 5 weeks at one of two altitudes(340 and 3800 m above sea level). Then, a subset of each group was acclimated to the opposite altitude for 8 weeks. We measured V̇O2max for each individual in hypoxia (PO2=13.5 kPa, 14%O2 at 3800 m) and normoxia (PO2=20.4 kPa, 21% O2 at 340 m) to control for PO2 effects. At 5 weeks of age, high altitude born mice attained significantly higher V̇O2max than low altitude born mice (37.1% higher in hypoxia and 72.1% higher in normoxia). Subsequently, deer mice acclimated for 8 weeks to high altitude had significantly higher V̇O2max regardless of their birth site (21.0% and 72.9% difference in hypoxia and normoxia,respectively). A significant development × acclimation site interaction comparing V̇O2maxin hypoxia and normoxia at 13 weeks of age suggests that acclimation effects depend on development altitude. Thus, reversible plasticity during adulthood cannot fully compensate for developmental effects on aerobic performance. We also found that differences in aerobic performance in previous studies may have been underestimated if animals from contrasting altitudes were measured at different PO2.
Antioxidative defence alterations in skeletal muscle during prolonged acclimation to cold: role ofl-arginine/NO-producing pathway
Authors: Petrović Vesna , Buzadžić Biljana , Korać Aleksandra , Vasilijević Ana , Janković Aleksandra , Mićunović Ksenija , Korać Bato 
Published: December 2007

SUMMARYEarly in cold acclimation (1–7 days), heat is produced by shivering,while late in cold acclimation (12–45 days), skeletal muscle contributes to thermogenesis by tissue metabolism other than contractions. Given that both thermogenic phases augment skeletal muscle aerobic power and reactive species production, we aimed in this study to examine possible changes in skeletal muscle antioxidative defence (AD) during early and late cold acclimation with special emphasis on the influence of the l-arginine/nitric oxide(NO)-producing pathway on the modulation of AD in this tissue. Adult Mill Hill hybrid hooded rat males were divided into two main groups: a control group,which was kept at room temperature (22±1°C), and a group maintained at 4±1°C for 45 days. The cold-acclimated group was divided into three subgroups: untreated, l-arginine treated and Nω-nitro-l-arginine methyl ester(l-NAME) treated. The AD parameters were determined in the gastrocnemius muscle on day 1, 3, 7, 12, 21 and 45 of cold acclimation. The results showed an improvement of skeletal muscle AD in both early and late cold acclimation. Clear phase-dependent changes were seen only in copper, zinc superoxide dismutase activity, which was increased in early cold acclimation but returned to the control level in late acclimation. In contrast, there were no phase-dependent changes in manganese superoxide dismutase, catalase,glutathione peroxidase, glutathione reductase and glutathione S-transferase,the activities of which were increased during the whole cold exposure,indicating their engagement in both thermogenic phases. l-Arginine in early cold acclimation accelerated the cold-induced AD response, while in the late phase it sustained increases achieved in the early period. l-NAME affected both early and late acclimation through attenuation and a decrease in the AD response. These data strongly suggest the involvement of the l-arginine/NO pathway in the modulation of skeletal muscle AD.
Treasures III: Social Issues in American Film, 1900–1934
Authors: Mellen Joan 
Published: December 2007

ABSTRACT
This review essay of a National Film Preservation Foundation archival DVD boxed set of fiction and non-fiction films from the Progressive era emphasizes the underlying optimism about the future that is discernible even in those films that treat harrowing subjects (such as social deprivation, violence, and industrial exploitation).
Control / Joe Strummer: The Future is Unwritten / This is England
Authors: Sinker Mark 
Published: December 2007

ABSTRACT
A trio of British films depicting the era of Punk deal in different ways with the idea of escape and rebellion against social norms. This essay compares the way the visual aesthetics, narrative, and music combine to depict youth subcultures in Control, Joe Strummer: The Future is Unwritten, and This Is England.
Gentle Iconoclast: An Interview with David Gatten
Authors: MacDonald Scott 
Published: December 2007

ABSTRACT
Scott MacDonald talks with filmmaker David Gatten about his multi-film exploration of the life and times of colonial Virginian William Byrd II, Secret History of the Dividing Line, A True Account in Nine Parts, in which Gatten considers the development of print culture, the arrival of digital, and the material nature of cinema.
World War II: Defending Park Values and Resources
Authors: McDONNELL JANET A. 
Published: December 2007

Abstract
This article focuses on the way in which the National Park Service (NPS) resisted demands for the consumptive use of park resources during World War II primarily through the use of carefully crafted arguments and powerful rhetoric, but also by enlisting the support of conservation groups and adopting compromise measures. These compromise measures allowed the military to use the parks for recreation, rehabilitation, training, and maneuvers, and in a few instances authorize some exploitive use of parks by timber, mining, and farming interests when necessary. Faced with wartime demands, the NPS was forced to articulate its purpose and mission as never before. As NPS leaders articulated their arguments, they developed and publicized several major themes: that park values were a valuable resource; that the NPS had a trust responsibility to protect the parks; and that the parks represented the restorative and inspirational power of nature. Its vigorous campaign in defense of park values and resources, along with the willingness to compromise, played an important role in ensuring the preservation of irreplaceable park resources.