bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primary cilia utilize glycoprotein-dependent adhesion mechanisms to stabilize long-lasting cilia-cilia contacts
Authors: Ott Carolyn , Elia Natalie , Jeong Suh Young , Insinna Christine , Sengupta Prabuddha , Lippincott-Schwartz Jennifer 
Published: April 2012

Abstract

Background
The central tenet of cilia function is sensing and transmitting information. The capacity to directly contact extracellular surfaces would empower primary cilia to probe the environment for information about the nature and location of nearby surfaces. It has been well established that flagella and other motile cilia perform diverse cellular functions through adhesion. We hypothesized that mammalian primary cilia also interact with the extracellular environment through direct physical contact.

Methods
We identified cilia in rod photoreceptors and cholangiocytes in fixed mouse tissues and examined the structures that these cilia contact in vivo. We then utilized an MDCK cell culture model to characterize the nature of the contacts we observed.

Results
In retina and liver tissue, we observed that cilia from nearby cells touch one another. Using MDCK cells, we found compelling evidence that these contacts are stable adhesions that form bridges between two cells, or networks between many cells. We examined the nature and duration of the cilia-cilia contacts and discovered primary cilia movements that facilitate cilia-cilia encounters. Stable adhesions form as the area of contact expands from a single point to a stretch of tightly bound, adjacent cilia membranes. The cilia-cilia contacts persisted for hours and were resistant to several harsh treatments such as proteases and DTT. Unlike many other cell adhesion mechanisms, calcium was not required for the formation or maintenance of cilia adhesion. However, swainsonine, which blocks maturation of N-linked glycoproteins, reduced contact formation. We propose that cellular control of adhesion maintenance is active because cilia adhesion did not prevent cell division; rather, contacts dissolved during mitosis as cilia were resorbed.

Conclusions
The demonstration that mammalian primary cilia formed prolonged, direct, physical contacts supports a novel paradigm: that mammalian primary cilia detect features of the extracellular space, not just as passive antennae, but also through direct physical contact. We present a model for the cycle of glycoprotein-dependent contact formation, maintenance, and termination, and discuss the implications for potential physiological functions of cilia-cilia contacts.
Trafficking in and to the primary cilium
Authors: Hsiao Yi-Chun , Tuz Karina , Ferland Russell J 
Published: April 2012

Abstract
Polarized vesicle trafficking is mediated by small GTPase proteins, such as Rabs and Arls/Arfs. These proteins have essential roles in maintaining normal cellular function, in part, through regulating intracellular trafficking. Moreover, these families of proteins have recently been implicated in the formation and function of the primary cilium. The primary cilium, which is found on almost every cell type in vertebrates, is an organelle that protrudes from the surface of the cell and functions as a signaling center. Interestingly, it has recently been linked to a variety of human diseases, collectively referred to as ciliopathies. The primary cilium has an exceptionally high density of receptors on its membrane that are important for sensing and transducing extracellular stimuli. Moreover, the primary cilium serves as a separate cellular compartment from the cytosol, providing for unique spatial and temporal regulation of signaling molecules to initiate downstream events. Thus, functional primary cilia are essential for normal signal transduction. Rabs and Arls/Arfs play critical roles in early cilia formation but are also needed for maintenance of ciliary function through their coordination with intraflagellar transport (IFT), a specialized trafficking system in primary cilia. IFT in cilia is pivotal for the proper movement of proteins into and out of this highly regulated organelle. In this review article, we explore the involvement of polarized vesicular trafficking in cilia formation and function, and discuss how defects in these processes could subsequently lead to the abnormalities observed in ciliopathies.
Risk of contrast induced nephropathy in the critically ill: a prospective, case matched study
Authors: Cely Cynthia M , Schein Roland MH , Quartin Andrew A 
Published: April 2012

Abstract
Introduction
Computerized tomography is frequently employed in the critically ill, often using intravenous radiocontrast material. Many of these patients have clinical features that are considered risk factors for contrast induced nephropathy, but are simultaneously at risk for renal injury from other factors related to their acute illnesses. The attributable risk for renal dysfunction from radiocontrast exposure has not been well quantified in this population.

Methods
A prospective matched cohort study was conducted of patients scanned with or without radiocontrast enhancement while receiving intensive care in a Veterans Affairs Medical Center. Patients were matched for pre-scan measured creatinine clearance, diabetes, mechanical ventilation, and vasopressor use. Measured clearance was followed for three days after scanning. Evolution of nephropathy, as determined by change in measured clearance, was compared within matched pairs.

Results
Fifty-three pairs of patients satisfied matching criteria. Unmatched characteristics were similar among the pairs, including serum creatinine variability during the week preceding scanning (67 ± 85% among contrast recipients, 63 ± 62% among others) and clinical risk factors for renal failure. In 29 pairs, pre-scan measured clearances were less than 60 mL/minute/1.73 m2. Following scanning, measured clearance declined by at least 33% in 14 contrast and 19 non-contrast patients (95% confidence interval for contrast associated difference in nephropathy rates -27% to 9%), while a 50% reduction in clearance persisted three days after scanning in three contrast and nine non-contrast patients (95% confidence interval for difference in rates -25% to 2%).

Conclusions
Among established intensive care unit patients declines in glomerular filtration following contrast-enhanced scanning are common, but these changes are far more likely to be attributable to factors other than the contrast exposure itself. The upper bound for the incidence of contrast induced renal injury lasting even three days was 2% in the population studied.
Time-lapse acoustic, transport, and NMR measurements to characterize microstructural changes of carbonate rocks during injection of CO2-rich water
Authors: Grombacher Denys , Vanorio Tiziana , Ebert Yael 
Published: April 2012

We investigated how changes induced in the microstructure of carbonate rocks by the injection of [Formula: see text]-rich water affect pore-network properties. In particular, we investigated from multiple perspectives the microstructural changes and types of porosity that alter the observable geophysical properties. We thereby refined our understanding of induced modification of the pore network. Our experimental protocol included a suite of time-lapse acoustic, transport, and nuclear magnetic resonance (NMR) measurements, along with scanning electron microscopy (SEM) and CT-scan images; these gave us complementary sensitivity to changes in different properties of the pore space. Induced porosity variations were smaller than in previous reported results because of chemomechanical compaction resulting from dissolution under pressure. No porosity enhancements larger than 0.8 pu were observed. Results indicated that dissolution occured primarily in the grain-coating cement and the microporosity of the micritic phase. Both caused the formation of cracklike pores around larger grains leading to a more compliant frame, causing both velocity reductions and an increased sensitivity of velocity to pressure. Chalky micritic facies exhibited velocity reductions of [Formula: see text], whereas micritic limestones, less prone to compaction and grain sliding, experienced smaller velocity reductions ([Formula: see text]). Because porosity enhancement was minimal, we hypothesized that the reductions were due to injection-induced reduction of grain-contact stiffness. Dissolution-induced compaction played an integral role also in the permeability response during injection. Compaction in pressure-sensitive chalky facies strongly counteracted the effects of dissolution, leading to negligible permeability and NMR response changes. In contrast, stiff micritic limestones with little dissolution-induced compaction exhibited larger permeability increases ([Formula: see text]). This work demonstrated the advantages of utilizing a suite of concurrent and independent measurements to build a more comprehensive interpretation of microstructure changes induced by injecting fluids that are in chemical disequilibrium with the host formation.
Pattern formation at the ocean surface: Sargassum distribution and the role of the eddy field
Authors: Zhong Yisen , Bracco Annalisa , Villareal Tracy A. 
Published: April 2012

Lay AbstractOrganisms that float at the ocean surface such as the macroalga Sargassum and the cyanobacterium Trichodesmium often accumulate in lines visible in satellite imagery. These lines have lateral scale separations of a few kilometers and cannot be explained by Langmuir circulation. Here we discuss the physical process responsible for the accumulation of floating materials in the ocean in the presence of mesoscale (tens of kilometers) and submesoscale (few kilometers) turbulence. Using high‐resolution simulations in both an idealized domain (a 3‐dimensional box where turbulence is excited by small‐scale winds and eddies form) and a realistic domain (western Gulf of Mexico, where extensive concentrations of floating Sargassum have been recorded in satellite images), we show that the distribution of tracers at the ocean surface departs rapidly from that observed a few meters below the surface. The strong divergence and convergence zones generated at the ocean surface by ageostrophic processes (i.e., processes for which an exact balance between the Coriolis force and the pressure gradient force is not attained) at scales between hundreds of meters and a few kilometers are responsible for the creation of lines where the floating material accumulates. Floating particles in the model simulations are expelled from the core of eddies and concentrate in small filaments. The resulting patterns are similar to the distribution of Sargassum seen in satellite images. Such organization may be common in many surface‐dwelling organisms and could play a role in enhancing biological interactions.
Vigorous SO42– influxviathe gills is balanced by enhanced SO42– excretion by the kidney in eels after seawater adaptation
Authors: Watanabe Taro , Takei Yoshio 
Published: April 2012

SUMMARYSulfate (SO42–) is maintained at ∼1 mmol–1 l–1 in teleost fishes that are exposed to media of varying SO42– concentrations. We first measured plasma SO42– concentration in euryhaline fishes that adapt to both SO42–-poor freshwater (&lt;0.5 mmol l) and SO42–-enriched seawater (30 mmol l–1). Unlike Mozambique tilapia and chum salmon, Japanese eels maintained higher plasma SO42– concentration in freshwater (6.2±2.3 mmol l–1) than in seawater (0.7±0.1 mmol l–1). We then analyzed the whole-body SO42– budget using 35SO42–. 35SO42– influx in seawater-adapted eels occurred by 84.5% via body surfaces and 15.5% via digestive tracts. The SO42– influx was higher in seawater eels (1.55 μmol kg–1 h–1) than in freshwater eels (0.09 μmol kg–1 min–1), but it was facilitated in freshwater eels when the difference in SO42– concentrations between plasma and environment was taken into account (freshwater eels, 6.2 vs 0.3 mmol l–1; seawater eels, 0.7 vs 30 mmol l–1). One hour after injection of 35SO42– into the blood of seawater eels, the kidney excreted ∼97% of the ionized form, whereas the radioactivity increased gradually in the medium and the rectal fluid more than 3 h after injection. As the radioactivity was poorly adsorbed by anion-exchange resin, 35SO42– in the blood may be incorporated into cells and excreted by the intestine, gills and skin, probably as mucus. These results show that freshwater eels take up SO42– actively from the environment, but seawater eels cope with the obligatory influx of SO42– through the gills by excreting excess SO42–via the kidney and in mucus.
Oesophageal chemoreceptors of blue crabs,Callinectes sapidus, sense chemical deterrents and can block ingestion of food
Authors: Aggio Juan F. , Tieu Ryan , Wei Amy , Derby Charles D. 
Published: April 2012

SUMMARYDecapod crustaceans such as blue crabs possess a variety of chemoreceptors that control different stages of the feeding process. All these chemoreceptors are putative targets for feeding deterrents that cause animals to avoid or reject otherwise palatable food. As a first step towards characterizing the chemoreceptors that mediate the effect of deterrents, we used a behavioral approach to investigate their precise location. Data presented here demonstrate that chemoreceptors located on the antennules, pereiopods and mouthparts do not mediate the food-rejection effects of a variety of deterrents, both natural and artificial to crabs. Crabs always searched for deterrent-laced food and took it to their oral region. The deterrent effect was manifested as either rejection or extensive manipulation, but in both cases crabs bit the food. The biting behavior is relevant because the introduction of food into the oral cavity ensured that the deterrents gained access to the oesophageal taste receptors, and so we conclude that they are the ones mediating rejection. Additional support comes from the fact that a variety of deterrent compounds evoked oesophageal dilatation, which is mediated by oesophageal receptors and has been linked to food rejection. Further, there is a positive correlation between a compound’s ability to elicit rejection and its ability to evoke oesophageal dilatation. The fact that deterrents do not act at a distance is in accordance with the limited solubility of most known feeding deterrents, and likely influences predator–prey interactions and their outcome: prey organisms will be attacked and bitten before deterrents become relevant.
Constraints-based stoichiometric analysis of hypoxic stress on steroidogenesis in fathead minnows, Pimephales promelas
Authors: Hala David , Petersen Lene H. , Martinovic Dalma , Huggett Duane B. 
Published: April 2012

SUMMARY
In this study, an in silico genome-scale metabolic model of steroidogenesis was used to investigate the effects of hypoxic stress on steroid hormone productions in fish. Adult female fathead minnows (Pimephales promelas) were exposed to hypoxia for 7 days with fish sub-sampled on days 1, 3 and 7 of exposure. At each time point, selected steroid enzyme gene expressions and steroid hormone productions were quantified in ovaries. Fold changes in steroid enzyme gene expressions were used to qualitatively scale transcript enzyme reaction constraints (akin to the range of an enzyme’s catalytic activity) in the in silico model. Subsequently, in silico predicted steroid hormone productions were qualitatively compared with experimental results. Key findings were as follows. (1) In silico gene deletion analysis identified highly conserved ‘essential’ genes required for steroid hormone productions. These agreed well (75%) with literature-published genes downregulated in vertebrates (fish and mammal) exposed to hypoxia. (2) Quantification of steroid hormones produced ex vivo from ovaries showed a significant reduction for 17β-estradiol and 17α,20β-dihydroxypregnenone production after 24 h (day 1) of exposure. This lowered 17β-estradiol production was concomitant with downregulation of cyp19a1a gene expression in ovaries. In silico predictions showed agreement with experimentation by predicting effects on estrogen (17β-estradiol and estrone) production. (3) Stochastic sampling of in silico reactions indicated that cholesterol uptake and catalysis to pregnenolone along with estrogen methyltransferase and glucuronidation reactions were also impacted by hypoxia. Taken together, this in silico analysis introduces a powerful model for pathway analysis that can lend insights on the effects of various stressor scenarios on metabolic functions.
Within-lifetime trade-offs but evolutionary freedom for hormonal and immunological traits: evidence from mice bred for high voluntary exercise
Authors: Downs Cynthia J. , Schutz Heidi , Meek Thomas H. , Dlugosz Elizabeth M. , Acosta Wendy , de Wolski Karen S. , Malisch Jessica L. , Hayes Jack P. , Garland Theodore 
Published: April 2012

SUMMARYChronic increases in circulating corticosterone (CORT) generally suppress immune function, but it is not known whether evolved increases necessarily have similar adverse effects. Moreover, the evolution of immune function might be constrained by the sharing of signaling molecules, such as CORT, across numerous physiological systems. Laboratory house mice (Mus domesticus Linnaeus) from four replicate lines selectively bred for high voluntary wheel running (HR lines) generally had baseline circulating CORT approximately twofold higher than in four non-selected control (C) lines. To test whether elevated baseline CORT suppresses the inflammatory response in HR mice, we injected females with lipopolysaccharide (LPS). All mice injected with LPS exhibited classic signs of an inflammatory response, including sickness behavior, loss of body mass, reduced locomotor activity (i.e. voluntary wheel running), enlarged spleens and livers, elevated hematocrit and elevated inflammatory cytokines. However, as compared with C mice, the inflammatory response was not suppressed in HR mice. Our results, and those of a previous study, suggest that selective breeding for high voluntary exercise has not altered immune function. They also suggest that the effects of evolved differences in baseline CORT levels may differ greatly from effects of environmental factors (often viewed as ‘stressors’) that alter baseline CORT during an individual’s lifetime. In particular, evolved increases in circulating levels of ‘stress hormones’ are not necessarily associated with detrimental suppression of the inflammatory response, presumably as a result of correlated evolution of other physiological systems (counter-measures). Our results have important implications for the interpretation of elevated stress hormones and of immune indicators in natural populations.
Redox biology of exercise: an integrative and comparative consideration of some overlooked issues
Authors: Nikolaidis Michalis G. , Kyparos Antonios , Spanou Chrysoula , Paschalis Vassilis , Theodorou Anastasios A. , Vrabas Ioannis S. 
Published: April 2012

SummaryThe central aim of this review is to address the highly multidisciplinary topic of redox biology as related to exercise using an integrative and comparative approach rather than focusing on blood, skeletal muscle or humans. An attempt is also made to re-define ‘oxidative stress’ as well as to introduce the term ‘alterations in redox homeostasis’ to describe changes in redox homeostasis indicating oxidative stress, reductive stress or both. The literature analysis shows that the effects of non-muscle-damaging exercise and muscle-damaging exercise on redox homeostasis are completely different. Non-muscle-damaging exercise induces alterations in redox homeostasis that last a few hours post exercise, whereas muscle-damaging exercise causes alterations in redox homeostasis that may persist for and/or appear several days post exercise. Both exhaustive maximal exercise lasting only 30 s and isometric exercise lasting 1–3 min (the latter activating in addition a small muscle mass) induce systemic oxidative stress. With the necessary modifications, exercise is capable of inducing redox homeostasis alterations in all fluids, cells, tissues and organs studied so far, irrespective of strains and species. More importantly, ‘exercise-induced oxidative stress’ is not an ‘oddity’ associated with a particular type of exercise, tissue or species. Rather, oxidative stress constitutes a ubiquitous fundamental biological response to the alteration of redox homeostasis imposed by exercise. The hormesis concept could provide an interpretative framework to reconcile differences that emerge among studies in the field of exercise redox biology. Integrative and comparative approaches can help determine the interactions of key redox responses at multiple levels of biological organization.
Tarantulas do not shoot silk from their legs: experimental evidence in four species of New World tarantulas
Authors: Pérez-Miles Fernando , Ortíz-Villatoro David 
Published: April 2012

SUMMARY
Theraphosid tarantulas, like all other spiders, secrete silk from spigots on the abdominal spinnerets. A few years ago, it was proposed that the large tarantula Aphonopelma seemanni could extrude silk from specialized spigots on the tarsi to help adhesion to vertical surfaces. This suggestion was later questioned because silk was not observed after the spinnerets had been sealed. Recently, experiments with the tarantula Grammostola rosea again suggested tarsal silk secretion. All observations of the supposed tarsal silk were made in spiders with functional spinnerets, thus contamination with silk coming from the spinnerets could not be excluded. Recent morphological arguments also questioned putative tarsal spigots and proposed that they are actually contact chemoreceptors. We here test the supposed tarsal silk secretion in Aphonopelma seemanni, Avicularia avicularia, Brachypelma vagans and Grammostola mollicoma using similar experimental conditions as the previous authors, but with sealed spinnerets. Our results clearly demonstrate that when spinnerets are sealed, tarantulas do not show any tarsal silk secretion. We reinterpret those putative tarsal spigots and discuss possible evolutionary implications of these findings.
Cannabinoid Stability in Authentic Oral Fluid after Controlled Cannabis Smoking
Authors: Lee Dayong , Milman Garry , Schwope David M , Barnes Allan J , Gorelick David A , Huestis Marilyn A 
Published: April 2012

Abstract

BACKGROUND
Defining cannabinoid stability in authentic oral fluid (OF) is critically important for result interpretation. There are few published OF stability data, and of those available, all employed fortified synthetic OF solutions or elution buffers; none included authentic OF following controlled cannabis smoking.

METHODS
An expectorated OF pool and a pool of OF collected with Quantisal™ devices were prepared for each of 10 participants. Δ9-Tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) stability in each of 10 authentic expectorated and Quantisal-collected OF pools were determined after storage at 4 °C for 1 and 4 weeks and at −20 °C for 4 and 24 weeks. Results within ±20% of baseline concentrations analyzed within 24 h of collection were considered stable.

RESULTS
All Quantisal OF cannabinoid concentrations were stable for 1 week at 4 °C. After 4 weeks at 4 °C, as well as 4 and 24 weeks at −20 °C, THC was stable in 90%, 80%, and 80% and THCCOOH in 89%, 40%, and 50% of Quantisal samples, respectively. Cannabinoids in expectorated OF were less stable than in Quantisal samples when refrigerated or frozen. After 4 weeks at 4 and −20 °C, CBD and CBN were stable in 33%–100% of Quantisal and expectorated samples; by 24 weeks at −20 °C, CBD and CBN were stable in ≤44%.

CONCLUSIONS
Cannabinoid OF stability varied by analyte, collection method, and storage duration and temperature, and across participants. OF collection with a device containing an elution/stabilization buffer, sample storage at 4 °C, and analysis within 4 weeks is preferred to maximize result accuracy.