bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for an apical Na–Cl cotransporter involved in ion uptake in a teleost fish
Authors: Hiroi Junya , Yasumasu Shigeki , McCormick Stephen D. , Hwang Pung-Pung , Kaneko Toyoji
Published: August 2008

Cation–chloride cotransporters, such as the Na+/K+/2Cl– cotransporter (NKCC) and Na+/Cl– cotransporter (NCC), are localized to the apical or basolateral plasma membranes of epithelial cells and are involved in active ion absorption or secretion. The objectives of this study were to clone and identify `freshwater-type' and `seawater-type' cation–chloride cotransporters of euryhaline Mozambique tilapia (Oreochromis mossambicus) and to determine their intracellular localization patterns within mitochondria-rich cells (MRCs). From tilapia gills, we cloned four full-length cDNAs homologous to human cation–chloride cotransporters and designated them as tilapia NKCC1a, NKCC1b, NKCC2 and NCC. Out of the four candidates, the mRNA encoding NKCC1a was highly expressed in the yolk-sac membrane and gills (sites of the MRC localization) of seawater-acclimatized fish, whereas the mRNA encoding NCC was exclusively expressed in the yolk-sac membrane and gills of freshwater-acclimatized fish. We then generated antibodies specific for tilapia NKCC1a and NCC and conducted whole-mount immunofluorescence staining for NKCC1a and NCC, together with Na+/K+-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR) and Na+/H+ exchanger 3 (NHE3), on the yolk-sac membrane of tilapia embryos acclimatized to freshwater or seawater. The simultaneous quintuple-color immunofluorescence staining allowed us to classify MRCs clearly into four types: types I, II, III and IV. The NKCC1a immunoreactivity was localized to the basolateral membrane of seawater-specific type-IV MRCs, whereas the NCC immunoreactivity was restricted to the apical membrane of freshwater-specific type-II MRCs. Taking account of these data at the level of both mRNA and protein, we deduce that NKCC1a is the seawater-type cotransporter involved in ion secretion by type-IV MRCs and that NCC is the freshwater-type cotransporter involved in ion absorption by type-II MRCs. We propose a novel ion-uptake model by MRCs in freshwater that incorporates apically located NCC. We also reevaluate a traditional ion-uptake model incorporating NHE3; the mRNA was highly expressed in freshwater, and the immunoreactivity was found at the apical membrane of other freshwater-specific MRCs.
Inductive transcription and protective role of fish heme oxygenase-1 under hypoxic stress
Authors: Wang Dan , Zhong Xue-Ping , Qiao Zhi-Xian , Gui Jian-Fang
Published: August 2008

Heme oxygenase-1 is the rate-limiting enzyme in the degradation of heme into biliverdin, carbon monoxide and free divalent iron. In this study, we cloned heme oxygenase isoform 1 (CaHO-1) from a hypoxia-tolerant teleost fish Carassius auratus. The full-length cDNA of CaHO-1 is 1247 bp and encodes a protein of 272 amino acids. RT-PCR and real-time PCR analysis indicated that CaHO-1 was predominantly transcribed in posterior kidney, head kidney, gill and intestine, and induction of gene transcription was observed predominantly in posterior kidney under hypoxic stress. Moreover, the hypoxia-induced transcription was confirmed in goldfish larvae and in in vitro cultured CAB cells. Fluorescence of the HO-1-GFP fusion protein revealed a cytoplasmic and plasma membrane localization, which was consistent with the putative transmembrane structure. Subsequently, we established a stably transfected CAB/pcDNA3.1-HO-1 cell line and a control CAB/pcDNA3.1 cell line, and found that the number of dead cells was obviously reduced in the pcDNA3.1-HO-1-transfected group following 4 days of hypoxic (1% O2) treatment in comparison with numerous detached dead cells in the control pcDNA3.1-transfected cells. Furthermore, a significant cell viability difference between the two kinds of transfected cells during hypoxia–reoxygenation was revealed. Therefore,the data suggest that fish HO-1 might play a significant protective role in cells in response to hypoxic stress.
An insect trap as habitat: cohesion-failure mechanism prevents adhesion ofPameridea roridulaebugs to the sticky surface of the plantRoridula gorgonias
Authors: Voigt Dagmar , Gorb Stanislav
Published: August 2008

The glandular trichomes of the plant Roridula gorgonias release an extremely adhesive, visco-elastic, resinous secretion that traps a variety of insects, including those having a considerable body size. However, the specialized mutualistic mirid bug Pameridea roridulae lives and walks on this sticky plant surface without being trapped. We have sought to reveal the mechanism underlying the apparent non-sticky nature of the cuticle of this bug. In this study, we have visualized intact plant and insect surfaces using cryo-scanning electron microscopy and measured the adhesive properties of the plant secretion on different surfaces. We present a combination of structural and experimental results that suggest that a thick and cohesively weak film of an outermost, epicuticular greasy secretion acts as a `sloughing-off' layer,preventing the formation of contacts between the sticky plant secretion and the solid insect cuticle. In a comparative study of fresh cuticle fractures of flies representing a typical prey of R. gorgonias, a thin,fragmentary layer of epicuticular grease was revealed. These results indicate that, when trapping prey, the plant adhesive might form proper contact with solid islands of the insect cuticle that are free of epicuticular grease.
Novel surfactant proteins are involved in the structure and stability of foam nests from the frogLeptodactylus vastus
Authors: Hissa Denise Cavalcante , Vasconcelos Ilka Maria , Carvalho Ana Fontenele Urano , Nogueira Vanessa Lúcia Rodrigues , Cascon Paulo , Antunes André Saraiva Leão , de Macedo Gorete Ribeiro , Melo Vânia Maria Maciel
Published: August 2008

Many amphibians lay their eggs in foam nests, which allow the eggs to be deposited out of the water. Analysis of some of these foam nests has revealed that they are a rich source of proteins with unusual primary structures and remarkable surfactant activity, named ranaspumins. The aim of this work was to study the foam nests of the frog Leptodactylus vastus in order to obtain information regarding their composition and function and to improve the understanding of ranaspumins, which are probably a novel class of surfactant proteins. Analyses of the foam fluid composition showed proteins and carbohydrates that presumably are responsible for providing nutrients for the developing tadpoles. Investigation of the function of foam fluid in chemical defence revealed no significant biological activity that could be associated with recognized defence compounds. However, foam fluid presented UV absorbance, suggesting a role in protection against sun damage, which is considered to be one of the possible causes of recently reported amphibian population declines. The foam nests do not prevent the colonization of microorganisms, such as the observed bacterial community of predominantly Gram-positive bacilli. L. vastus foam fluid shows a strong surfactant activity that was associated with their proteins and this activity seems to be due mainly to a protein named Lv-ranaspumin. This protein was isolated by ion-exchange chromatography and found to be a 20 kDa monomeric molecule with the following N-terminal sequence: FLEGFLVPKVVPGPTAALLKKALDD. This protein did not show any match to known proteins or structures, which suggests that it belongs to a new class of surfactant protein.
Phonotactic selectivity in two cryptic species of gray treefrogs: effects of differences in pulse rate, carrier frequency and playback level
Authors: Gerhardt H. Carl
Published: August 2008

The two main spectral components of the advertisement calls of two species of North American gray treefrogs (Hyla chrysoscelis and H. versicolor) overlap broadly in frequency, and the frequency of each component matches the sensitivity of one of the two different auditory inner ear organs. The calls of the two species differ in the shape and repetition rate (pulse rate) of sound pulses within trills. Standard synthetic calls with one of these spectral peaks and the pulse rate typical of conspecific calls were tested against synthetic alternatives that had the same spectral peak but a different pulse rate. The results were generalized over a wide range of playback levels. Selectivity based on differences in pulse rate depended on which spectral peak was used in some tests, and greater pulse-rate selectivity was usually observed when the low-frequency rather than the high-frequency peak was used. This effect was more pronounced and occurred over a wider range of playback levels in H. versicolor than in H. chrysosceliswhen the pulse rate of the alternative was higher than that of the standard call. In tests at high playback levels with an alternative of 15 pulses s–1, however, females of H. versicolor showed greater selectivity for the standard call when the high-frequency rather than the low-frequency spectral peak was used. This last result may reflect the different ways in which females of the two species assess trains of pulses,and the broad implications for understanding the underlying auditory mechanisms are discussed.
The role of infrequent and extraordinary deep dives in leatherback turtles (Dermochelys coriacea)
Authors: Houghton Jonathan D. R. , Doyle Thomas K. , Davenport John , Wilson Rory P. , Hays Graeme C.
Published: August 2008

Infrequent and exceptional behaviours can provide insight into the ecology and physiology of a particular species. Here we examined extraordinarily deep(300–1250 m) and protracted (>1h) dives made by critically endangered leatherback turtles (Dermochelys coriacea) in the context of three previously suggested hypotheses: predator evasion, thermoregulation and exploration for gelatinous prey. Data were obtained via satellite relay data loggers attached to adult turtles at nesting beaches(N=11) and temperate foraging grounds (N=2), constituting a combined tracking period of 9.6 years (N=26,146 dives) and spanning the entire North Atlantic Ocean. Of the dives, 99.6% (N=26,051) were to depths <300 m with only 0.4% (N=95) extending to greater depths(subsequently termed `deep dives'). Analysis suggested that deep dives: (1)were normally distributed around midday; (2) may exceed the inferred aerobic dive limit for the species; (3) displayed slow vertical descent rates and protracted durations; (4) were much deeper than the thermocline; and (5)occurred predominantly during transit, yet ceased once seasonal residence on foraging grounds began. These findings support the hypothesis that deep dives are periodically employed to survey the water column for diurnally descending gelatinous prey. If a suitable patch is encountered then the turtle may cease transit and remain within that area, waiting for prey to approach the surface at night. If unsuccessful, then migration may continue until a more suitable site is encountered. Additional studies using a meta-analytical approach are nonetheless recommended to further resolve this matter.
Crowding, an environmental stressor, blocks long-term memory formation inLymnaea
Authors: De Caigny Pascaline , Lukowiak Ken
Published: August 2008

Crowding is an environmental stressor. We found that this stressor altered(i.e. prevented) the ability of Lymnaea to form long-term memory(LTM) following operant conditioning of aerial respiratory behaviour. The ability to form LTM was compared between snails that had been crowded (20 snails per 100 ml of pond water) and those maintained in uncrowded conditions(two snails per 100 ml of pond water). Crowding either immediately before or after two different operant conditioning procedures – the traditional training procedure and the memory augmentation procedure – blocked LTM formation. However, if crowding is delayed by more than 1h following training or if crowding stops 1h before training, LTM results. If memory is already formed, crowding does not block memory recall. Pond water from a crowded aquarium or crowding with clean shells from dead snails, or a combination of both, is insufficient to block LTM formation. Finally, crowding does not block intermediate-term memory (ITM) formation. Since ITM is dependent on new protein synthesis whereas LTM is dependent on both new protein synthesis and altered gene activity, we hypothesize that crowding alters the genomic activity in neurons necessary for LTM formation.
Utility of Kallikrein-Related Peptidases (KLKs) as Cancer Biomarkers
Authors: Emami Nashmil , Diamandis Eleftherios P
Published: August 2008

Background: The human kallikrein-related peptidase (KLK) family consists of 15 highly conserved serine proteases, which are encoded by the largest uninterrupted cluster of protease genes in the human genome. To date, several members of the family have been reported as potential cancer biomarkers. Although primarily known for their biomarker value in prostate, ovarian, and breast cancers, more recent data suggest analogous roles of KLKs in several other cancers, including gastrointestinal, head and neck, lung, and brain malignancies. Among the proposed KLK cancer biomarkers, prostate-specific antigen (also known as KLK3) is the most widely recognized member in urologic oncology.

Content: Despite substantial progress in the understanding of the biomarker utility of individual KLKs, the current challenge lies in devising biomarker panels to increase the accuracy of prognosis, prediction of therapy, and diagnosis. To date, multiparametric KLK panels have been proposed for prostate, ovarian, and lung cancers. In addition to their biomarker utility, emerging evidence has revealed a number of critical functional roles for KLKs in the pathogenesis of cancer and their potential use as therapeutic targets.

Summary: KLKs have biomarker utility in many cancer types but individually lack sufficient specificity or sensitivity to be used in clinical practice; however, groups of KLKs and other candidate biomarkers may offer improved performance.
Adhesion to wet cellulose – Comparing adhesive layer-by-layer assembly to coating polyelectrolyte complex suspensions 2nd ICC 2007, Tokyo, Japan, October 25–29, 2007
Authors: Feng Xianhua , Zhang Dan , Pelton Robert
Published: August 2008

Polyelectrolyte complexes are routinely used as adhesives to strengthen fiber-fiber contacts in paper. This work evaluates different approaches to putting the polyelectrolyte complexes into the adhesive joint. Instead of conventional wet paper mechanical testing, a wet cellulose film delamination technique was employed permitting direct comparison of different approaches to applying the polymeric adhesive to the cellulose-cellulose joint. The adhesion strengths of layer-by-layer polyelectrolyte complexes assembled on wet cellulose films and the adhesion strengths of the corresponding polyelectrolyte complex coated on wet cellulose films are compared. The wet adhesion strengths were measured by peel delamination. The polyelectrolyte complexes were based on mixtures of cationic polyvinylamine (PVAm) and anionic carboxymethyl cellulose (CMC). The layer-by-layer assemblies of PVAm and CMC yielded stronger wet adhesion than did coated films of the corresponding colloidal complexes or pure PVAm at the same coverage (mass of polymer/joint area). The role of CMC was to give ionic crosslinks with PVAm which increase the cohesive strength of thick PVAm layers. PVAm gives much stronger wet adhesion to cellulose compared to the oxidized silicon wafer surfaces. It is proposed that imine and aminal bonds can form between the polyamine and hemiacetals in the regenerated cellulose films which cannot form with silica.
A Comparison of Four Office Chairs Using Biomechanical Measures
Authors: Bush Tamara Reid , Hubbard Robert P.
Published: August 2008

Objective: The authors sought to use biomechanical measures, including motion and pressure, to compare four office chairs. Background: The fit of a person to a chair is related to the geometric and kinematic compatibility between the two. This geometric compatibility influences the motions that are allowed or prohibited and the support pressures at the body-chair interface. Thus, during evaluation, it is necessary to treat the chair and user as a system. Method: Four dynamic test conditions were evaluated with 14 participants of varying anthropometries. Test conditions were selected to compare the ability to accommodate primary and secondary motions (recline and spinal articulation) of seated occupants. The ability of a chair to allow recline, yet maintain head and hand positions, was compared across chairs. Also, the ability of each chair to allow and support spinal articulation was evaluated. Motion data for the chair, head, thorax, pelvis, and extremities were collected along with chair back pressures. Upon completion of testing, subjective assessments were also conducted. Results: Statistically significant differences were found between chairs relative to head and hand motions. Also, significant differences were noted for the chairs' ability to move with the body during spinal articulation and the ability to provide support. Subjective assessments also yielded differences. Conclusions: Biomechanical analyses using motions and pressures can be conducted on office chairs with significant differences detected in their performance. Application: Biomechanical assessments can be used to compare and contrast office chairs in terms that are relatable to fatigue reduction as well as operator performance.
Testing a Multidimensional Nonveridical Aircraft Collision Avoidance System
Authors: Knecht William R.
Published: August 2008

Objective: This study explores operators' ability to use a multidimensional, nonveridical control display. Background: Veridical displays represent realistic scenes. State space displays represent nonveridical n-dimensional information based on informative coordinate axes plus variable features such as color and shading. Empirical investigation of state space displays is relatively new to human factors research. Method: Twelve licensed general aviation pilots flew flight scenarios, trying to deviate as little as possible from a preassigned course while still maintaining standard en route separation from traffic. Flight performance using only a veridical cockpit display of traffic information (CDTI) was compared with performance using the CDTI augmented by a 4-D nonveridical state space collision avoidance system (CDTI+4CAS). Results: Using moderate traffic density and complex traffic geometry, the CDTI+4CAS condition showed performance superiority over the baseline CDTI-only condition for five of five dependent measures of maneuver efficiency, four of four measures of maneuver safety, and six of nine measures of user workload. Conclusion: Results suggest that nonveridical information display may enhance operator performance on a control task involving simultaneous processing of multidimensional information. Application: Nonveridical information displays have potential application wherever human control of multidimensional processes is involved.
Visual Misperception in Aviation: Glide Path Performance in a Black Hole Environment
Authors: Gibb Randy , Schvaneveldt Roger , Gray Rob
Published: August 2008

Objective: We sought to improve understanding of visual perception in aviation to mitigate mishaps in approaches to landing. Background: Research has attempted to identify the most salient visual cues for glide path performance in impoverished visual conditions. Numerous aviation accidents caused by glide path overestimation (GPO) have occurred when a low glide path was induced by a black hole illusion (BHI) in featureless terrain during night approaches. Method: Twenty pilots flew simulated approaches under various visual cues of random terrain objects and approach lighting system (ALS) configurations. Performance was assessed relative to the desired 3° glide path in terms of precision, bias, and stability. Results: With the high-ratio (long, narrow) runway, the overall performance between 8.3 and 0.9 km from the runway depicted a concave approach shape found in BHI mishaps. The addition of random terrain objects failed to improve glide path performance, and an ALS commonly used at airports induced GPO and the resulting low glide path. The worst performance, however, resulted from a combination ALS consisting of both side and approach lights. Surprisingly, novice pilots flew more stable approaches than did experienced pilots. Conclusions: Low, unsafe approaches occur frequently in conditions with limited global and local visual cues. Approach lights lateral of the runway may counter the bias of the BHI. The variability suggested a proactive, cue-seeking behavior among experienced pilots as compared with novice pilots. Application: Visual spatial disorientation training in flight simulators should be used to demonstrate visual misperceptions in black hole environments and reduce pilots' confidence in their limited visual capabilities.
Assessing Design Features of Virtual Keyboards for Text Entry
Authors: O'Brien Marita A. , Rogers Wendy , Fisk Arthur D. , Richman Mark
Published: August 2008

Objective: The present research examined design of a virtual keyboard for text entry with a rotary controller, emphasizing users who differ in age and system experience. Background: Existing research has minimally addressed usage frequency, age, and the effects of display shape and letter arrangement on movement and visual search components of text entry tasks. The present research was conducted to close these gaps. Method: Two experiments were completed to examine younger (18—28 years) and older (60—75 years) adults' movement and visual search capabilities using four keyboard shapes and three keyboard arrangements. In a third experiment examining combined effects on shape design, 32 younger (18—28 years) and 32 older (60—75 years) adults entered words on the two best shapes from the first experiments. Results: For the movement task, movement time was lowest for shapes with higher shape-controller compatibility. For the visual search task, search time and accuracy were best on the alphabetic arrangement. In the combined task, shape did not significantly influence performance at different levels of practice. Transfers, however, suggested that the shape with salient visual features elicited a text entry strategy for older adults that may promote more consistent performance under occasional usage. Conclusion: The studies together demonstrate that keyboard shape is important for efficient performance. Shape-controller compatibility facilitated performance in both age groups. Salient features facilitate performance, especially for older adults. In nearly all cases alphabetic arrangement yielded the best performance. Application: Recommendations are provided for virtual keyboard design for different usage frequencies, contexts, and users.
Display Dimensionality and Conflict Geometry Effects on Maneuver Preferences for Resolving In-Flight Conflicts
Authors: Thomas Lisa C. , Wickens Christopher D.
Published: August 2008

Objective: Two experiments explored the effects of display dimensionality, conflict geometry, and time pressure on pilot maneuvering preferences for resolving en route conflicts. Background: With the presence of a cockpit display of traffic information (CDTI) that provides graphical airspace information, pilots can use a variety of conflict resolution maneuvers in response to how they perceive the conflict. Inconsistent preference findings from previous research on conflict resolution using CDTIs may be attributable to inherent ambiguities in 3-D perspective displays and/or a limited range of conflict geometries. Methods: Pilots resolved predicted conflicts using CDTIs with three levels of display dimensionality; the first had two 2-D orthogonal views, the second depicted the airspace in two alternating 3-D perspective views, and the third had a pilot-controlled swiveling viewpoint. Results: Pilots demonstrated the same preferences that have been observed in previous research for vertical over lateral maneuvers in low workload and climbs over descents for level-flight conflicts. With increasing workload the two 3-D perspective displays, but not the 2-D displays, resulted in an increased preference for lateral over vertical maneuvers. Increased time pressure resulted in increased vertical maneuvers, an effect again limited to the two 3-D perspective displays. Conclusion: Resolution preferences were more affected by workload and time pressure when the 3-D perspective displays were used, as compared with the 2-D displays, although overall preferences were milder than in previous studies. Application: Investigating maneuver preferences using the strategic flight planning paradigm employed in this study may be the key to better ensure pilot acceptance of computer-generated resolution maneuvers.
Designing an Information Search Interface for Younger and Older Adults
Authors: Pak Richard , Price Margaux M.
Published: August 2008

Objective: The present study examined Web-based information retrieval as a function of age for two information organization schemes: hierarchical organization and one organized around tags or keywords. Background: Older adults' performance in information retrieval tasks has traditionally been lower compared with younger adults'. The current study examined the degree to which information organization moderated age-related performance differences on an information retrieval task. The theory of fluid and crystallized intelligence may provide insight into different kinds of information architectures that may reduce age-related differences in computer-based information retrieval performance. Method: Fifty younger (18—23 years of age) and 50 older (55—76 years of age) participants browsed a Web site for answers to specific questions. Half of the participants browsed the hierarchically organized system (taxonomy), which maintained a one-to-one relationship between menu link and page, whereas the other half browsed the tag-based interface, with a many-to-one relationship between menu and page. This difference was expected to interact with age-related differences in fluid and crystallized intelligence. Results: Age-related differences in information retrieval performance persisted; however, a tag-based retrieval interface reduced age-related differences, as compared with a taxonomical interface. Conclusion: Cognitive aging theory can lead to interface interventions that reduce age-related differences in performance with technology. In an information retrieval paradigm, older adults may be able to leverage their increased crystallized intelligence to offset fluid intelligence declines in a computer-based information search task. Application: More research is necessary, but the results suggest that information retrieval interfaces organized around keywords may reduce age-related differences in performance.
Reward Facilitates Tactile Judgments and Modulates Hemodynamic Responses in Human Primary Somatosensory Cortex
Authors: Pleger Burkhard , Blankenburg Felix , Ruff Christian C. , Driver Jon , Dolan Raymond J.
Published: August 2008

Reinforcing effects of reward on action are well established, but possible effects on sensory function are less well explored. Here, using functional magnetic resonance imaging, we assessed whether reward can influence somatosensory judgments and modulate activity in human somatosensory cortex. Participants discriminated electrical somatosensory stimuli on an index finger with correct performance rewarded financially at trial end, at one of four different anticipated levels. Higher rewards improved tactile performance and led to increased hemodynamic signals from ventral striatum on rewarded trials. Remarkably, primary somatosensory cortex contralateral to the judged hand was reactivated at the point of reward delivery, despite the absence of concurrent somatosensory input at that time point. This side-specific reactivation of primary somatosensory cortex increased monotonically with level of reward. Moreover, the level of reward received on a particular trial influenced somatosensory performance and neural activity on the subsequent trial, with better discrimination and enhanced hemodynamic response in contralateral primary somatosensory cortex for trials that followed higher rewards. These results indicate that rewards can influence not only classical reward-related regions, but also early somatosensory cortex when a decision is required for that modality.
Seasonal effects on the response of ovarian follicles to IGF1 in mares
Authors: Doyle L K , Hogg C O , Watson E D , Donadeu F X
Published: August 2008

The response of follicles to IGF1 was compared between the transition into the ovulatory season (transitional period) and the ovulatory season (ovulatory period) in eight mares using a cross-over experimental design within periods. Granulosa cells were collected from follicles 15–24 or 25–34 mm and expression of IGF1R, IGF2R, FSHR, LHCGR and PAPPA was determined by qPCR. In addition, 10 mg IGF1 or vehicle were injected into the largest follicle (transitional period) or the second largest follicle (ovulatory period) of a follicular wave before the beginning of diameter deviation between the two largest follicles (mean diameters at injection 19.2 and 20.0 mm during transitional and ovulatory periods respectively). Follicular fluid was collected 24 h after injection for determination of free IGF1, IGFBP, inhibin A and oestradiol levels. Granulosa cells from follicles 25–34 mm, but not follicles 15–24 mm, expressed higher levels of IGF1R (P=0.01), FSHR (P<0.007) and LHCGR (P=0.09) during the ovulatory period than during the transitional period, whereas IGF2R expression was higher in transitional than ovulatory follicles (P=0.06). Follicular IGFBP2 levels were not different (P>0.1) between periods and treatments, whereas IGFBP5 levels were higher (P<0.05) during the ovulatory period. Finally, IGF1 injection before the beginning of deviation induced an approximately twofold increase (P=0.01) in follicular inhibin A levels during each period and did not affect oestradiol (P>0.1). These results suggest that, as during ovulatory waves, equine follicles during transitional waves are responsive to IGF1 before the beginning of deviation and that, therefore, inadequate IGF1 responsiveness before deviation may not underlie the deficient development of dominant follicles during transition.
Survey of the biological etiology of transsexualism
Authors: Kórász Krisztián , Simon Lajos
Published: August 2008

A nemi identitás zavara – vagy ahogyan széleskörűen ismert: a transzszexualizmus – igen összetett klinikai entitás. A magatartásorvoslás területén dolgozó kutatók és orvosok általános vélekedése, hogy a transzszexualizmus jól azonosítható és diagnosztizálható, a mindennapokban a személyt gátló zavar, amely sebészeti úton, nemi átalakító műtéttel gyógyítható. Habár a nemiidentitás-zavar pontos kóroktana nem ismert, eredetének több környezeti, genetikai és anatómiai elméletét is leírták. A szerzők a lehetséges genetikai, hormonális, immunológiai és anatómiai okokat tekintik át közleményükben. Vázolják a jövőbeli kutatási irányokat, kiemelve az előremutató jellemzőket.
Putative Dental Pulp-Derived Stem/Stromal Cells Promote Proliferation and Differentiation of Endogenous Neural Cells in the Hippocampus of Mice
Authors: Huang Anderson Hsien-Cheng , Snyder Brooke R. , Cheng Pei-Hsun , Chan Anthony W.S.
Published: August 2008

Until now, interest in dental pulp stem/stromal cell (DPSC) research has centered on mineralization and tooth repair. Beginning a new paradigm in DPSC research, we grafted undifferentiated, untreated DPSCs into the hippocampus of immune-suppressed mice. The rhesus DPSC (rDPSC) line used was established from the dental pulp of rhesus macaques and found to be similar to human bone marrow/mesenchymal stem cells, which express Nanog, Rex-1, Oct-4, and various cell surface antigens, and have multipotent differentiation capability. Implantation of rDPSCs into the hippocampus of mice stimulated proliferation of endogenous neural cells and resulted in the recruitment of pre-existing Nestin+ neural progenitor cells (NPCs) and β-tubulin-III+ mature neurons to the site of the graft. Additionally, many cells born during the first 7 days after implantation proliferated, forming NPCs and neurons, and, to a lesser extent, underwent astrogliosis, forming astrocytes and microglia, by 30 days after implantation. Although the DPSC graft itself was short term, it had long-term effects by promoting growth factor signaling. Implantation of DPSCs enhanced the expression of ciliary neurotrophic factor, vascular endothelial growth factor, and fibroblast growth factor for up to 30 days after implantation. In conclusion, grafting rDPSCs promotes proliferation, cell recruitment, and maturation of endogenous stem/progenitor cells by modulating the local microenvironment. Our results suggest that DPSCs have a valuable, unique therapeutic potential, specifically as a stimulator and modulator of the local repair response in the central nervous system. DPSCs would be a preferable cell source for therapy due to the possibility of a “personalized” stem cell, avoiding the problems associated with host immune rejection.

Disclosure of potential conflicts of interest is found at the end of this article.
Constitutive Expression of HIF-1α and HIF-2α in Bone Marrow Stromal Cells Differentially Promotes Their Proangiogenic Properties
Authors: Ben-Shoshan Jeremy , Schwartz Shulamit , Luboshits Galia , Maysel-Auslender Sofia , Barzelay Aya , Polak-Charcon Sylvie , Tzahor Eldad , Barshack Iris , Barak Adiel , Levkovitch-Verbin Hani , Keren Gad , George Jacob
Published: August 2008

Bone marrow stromal cells (BMSCs) contain progenitors capable of participating in postnatal angiogenesis. Hypoxia-inducible factors (HIFs) mediate endothelial activation by driving the expression of multiple angiogenic factors. We explored the potential of HIF-1α and HIF-2α modification in BMSCs, as a tool to improve cell-based angiogenic therapy. BMSCs were retrovirally transduced to express stable forms of HIF-1α and HIF-2α. HIF-1α and, to a greater extent, HIF-2α overexpression promoted differentiation of BMSCs to the endothelial lineage, evident by CD31 and Tie-2 expression and improved adhesive properties. Whereas chemotaxis toward stromal-derived factor 1 was higher in both HIF-α-expressing BMSCs, enhanced migration toward vascular endothelial growth factor was found only following overexpression of HIF-2α, supported by a robust expression of its receptor, Flk-1. HIF-α expression was associated with upregulation of angiogenic proteins and improved tube formation. Cytokine arrays of endothelial cells stimulated by medium collected from HIF-α-expressing BMSCs revealed further angiogenic activation and improved adhesive capacity. Eventually, delivery of HIF-2α-transduced BMSCs induced a more robust angiogenic response, compared with sham-transduced or HIF-1α-transduced BMSCs in the corneal micropocket angiogenesis model. Our results support the use of HIF-α genes, particularly HIF-2α, to augment the efficacy of future cell-based therapy.

Disclosure of potential conflicts of interest is found at the end of this article.
Zfp143 Regulates Nanog Through Modulation of Oct4 Binding
Authors: Chen Xi , Fang Fang , Liou Yih-Cherng , Ng Huck-Hui
Published: August 2008

Identification of regulators governing the maintenance of embryonic stem (ES) cells is crucial to the understanding of ES cell biology. We identified a zinc finger protein, Zfp143, as a novel regulator for self-renewal. Depletion of Zfp143 by RNA interference causes loss of self-renewal of ES cells. Chromatin immunoprecipitation and electrophoretic mobility shift assays show the direct binding of Zfp143 to the Nanog proximal promoter. Knockdown of Zfp143 or mutation of the Zfp143 binding motif significantly downregulates Nanog proximal promoter activity. Importantly, enforced expression of Nanog is able to rescue the Zfp143 knockdown phenotype, indicating that Nanog is one of the key downstream effectors of Zfp143. More interestingly, we further show that Zfp143 regulates Nanog expression through modulation of Oct4 binding. Coimmunoprecipitation experiments revealed that Zfp143 and Oct4 physically interact with each other. This interaction is important because Oct4 binding to the Nanog promoter is promoted by Zfp143. Our study reveals a novel regulator functionally important for the self-renewal of ES cells and provides new insights into the expanded regulatory circuitry that maintains ES cell pluripotency.

Disclosure of potential conflicts of interest is found at the end of this article.
Cyclic ADP-Ribose-Mediated Expansion and Stimulation of Human Mesenchymal Stem Cells by the Plant Hormone Abscisic Acid
Authors: Scarfì Sonia , Ferraris Chiara , Fruscione Floriana , Fresia Chiara , Guida Lucrezia , Bruzzone Santina , Usai Cesare , Parodi Alessia , Millo Enrico , Salis Annalisa , Burastero Giorgio , De Flora Antonio , Zocchi Elena
Published: August 2008

Abscisic acid (ABA) is a phytohormone involved in fundamental processes in higher plants. Endogenous ABA biosynthesis occurs also in lower Metazoa, in which ABA regulates several physiological functions by activating ADP-ribosyl cyclase (ADPRC) and causing overproduction of the Ca2+-mobilizing second messenger cyclic ADP-ribose (cADPR), thereby enhancing intracellular Ca2+ concentration ([Ca2+]i). Recently, production and release of ABA have been demonstrated to take place also in human granulocytes, where ABA behaves as a proinflammatory hormone through the same cADPR/[Ca2+]i signaling pathway described in plants and in lower Metazoa. On the basis of the fact that human mesenchymal stem cells (MSC) express ADPRC activity, we investigated the effects of ABA and of its second messenger, cADPR, on purified human MSC. Both ABA and cADPR stimulate the in vitro expansion of MSC without affecting differentiation. The underlying mechanism involves a signaling cascade triggered by ABA binding to a plasma membrane receptor and consequent cyclic AMP-mediated activation of ADPRC and of the cADPR/[Ca2+]i system. Moreover, ABA stimulates the following functional activities of MSC: cyclooxygenase 2-catalyzed production of prostaglandin E2 (PGE2), release of several cytokines known to mediate the trophic and immunomodulatory properties of MSC, and chemokinesis. Remarkably, ABA proved to be produced and released by MSC stimulated by specific growth factors (e.g., bone morphogenetic protein-7), by inflammatory cytokines, and by lymphocyte-conditioned medium. These data demonstrate that ABA is an autocrine stimulator of MSC function and suggest that it may participate in the paracrine signaling among MSC, inflammatory/immune cells, and hemopoietic progenitors.

Disclosure of potential conflicts of interest is found at the end of this article.
Metformin induces oxidative stress in white adipocytes and raises uncoupling protein 2 levels
Authors: Anedda Andrea , Rial Eduardo , González-Barroso M Mar
Published: August 2008

Metformin is a drug widely used to treat type 2 diabetes. It enhances insulin sensitivity by improving glucose utilization in tissues like liver or muscle. Metformin inhibits respiration, and the decrease in cellular energy activates the AMP-activated protein kinase that in turn switches on catabolic pathways. Moreover, metformin increases lipolysis and β-oxidation in white adipose tissue, thereby reducing the triglyceride stores. The uncoupling proteins (UCPs) are transporters that lower the efficiency of mitochondrial oxidative phosphorylation. UCP2 is thought to protect against oxidative stress although, alternatively, it could play an energy dissipation role. The aim of this work was to analyse the involvement of UCP2 on the effects of metformin in white adipocytes. We studied the effect of this drug in differentiating 3T3-L1 adipocytes and found that metformin causes oxidative stress since it increases the levels of reactive oxygen species (ROS) and lowers the aconitase activity. Variations in UCP2 protein levels parallel those of ROS. Metformin also increases lipolysis in these cells although only when the levels of ROS and UCP2 have decreased. Hence, UCP2 does not appear to be needed to facilitate fatty acid oxidation. Furthermore, treatment of C57BL/6 mice with metformin also augmented the levels of UCP2 in epididymal white adipose tissue. We conclude that metformin treatment leads to the overexpression of UCP2 in adipocytes to minimize the oxidative stress that is probably due to the inhibition of respiration caused by the drug.
EXPLOITED SPECIES IMPACTS ON TROPHIC LINKAGES ALONG REEF–SEAGRASS INTERFACES IN THE FLORIDA KEYS
Authors: Valentine John F. , Heck Kenneth L. , Blackmon Derrick , Goecker Margene E. , Christian Juliet , Kroutil Ryan M. , Peterson Bradley J. , Vanderklift Mathew A. , Kirsch Kevin D. , Beck Mike
Published: August 2008

The removal of fish biomass by extensive commercial and recreational fishing has been hypothesized to drastically alter the strength of trophic linkages among adjacent habitats. We evaluated the effects of removing predatory fishes on trophic transfers between coral reefs and adjacent seagrass meadows by comparing fish community structure, grazing intensity, and invertebrate predation potential in predator‐rich no‐take sites and nearby predator‐poor fished sites in the Florida Keys (USA). Exploited fishes were more abundant at the no‐take sites than at the fished sites. Most of the exploited fishes were either omnivores or invertivores. More piscivores were recorded at no‐take sites, but most (∼95%) were moderately fished and unexploited species (barracuda and bar jacks, respectively). Impacts of these consumers on lower trophic levels were modest. Herbivorous and smaller prey fish (<10 cm total length) densities and seagrass grazing diminished with distance from reefs and were not negatively impacted by the elevated densities of exploited fishes at no‐take sites. Predation by reef fishes on most tethered invertebrates was high, but exploited species impacts varied with prey type. The results of the study show that, even though abundances of reef‐associated fishes have been reduced at fished sites, there is little evidence that this has produced cascading trophic effects or interrupted cross‐habitat energy exchanges between coral reefs and seagrasses.
ARE SHRUBLAND BIRDS EDGE SPECIALISTS
Authors: Schlossberg Scott , King David I.
Published: August 2008

In studies of forest fragmentation, birds of scrubby, early‐successional habitats are considered edge specialists. Because these birds are assumed to thrive in fragmented, edge‐dominated areas, their landscape ecology has received little attention from ecologists. With populations of shrubland birds declining throughout the eastern United States, the question of whether or not these birds really prefer edge habitats has important conservation implications. We used a meta‐analysis to test how edges affect the abundance of shrubland birds in early‐successional habitats. We analyzed data for 17 species from seven studies that compared the abundances of birds in the interiors and edges of regenerating clearcuts surrounded by mature forest. The meta‐analysis clearly showed that shrubland birds avoid edges. All 17 species tested had higher abundances in patch centers than along edges, and edge effects were significant for 8 of 17 species. The key implication of this result is that small or irregular patches, dominated by edge, are unlikely to provide suitable habitat for shrubland birds. Thus, management for these declining species should involve providing large patches and minimizing edges. These findings demonstrate the importance of testing widely accepted ecological classifications and the need to view landscape ecology from the perspective of non‐forest wildlife.
Subchronic exposure of honeybees to sublethal doses of pesticides: Effects on behavior
Authors: Aliouane Yassine , el Hassani Adessalam K. , Gary Vincent , Armengaud Catherine , Lambin Michel , Gauthier Monique
Published: August 2008

Laboratory bioassays were conducted to evaluate the effects on honeybee behavior of sublethal doses of insecticides chronically administered orally or by contact. Emergent honeybees received a daily dose of insecticide ranging from one-fifth to one-five-hundredth of the median lethal dose (LD50) during 11 d. After exposure to fipronil (0.1 and 0.01 ng/bee), acetamiprid (1 and 0.1 μg/bee), or thiamethoxam (1 and 0.1 ng/bee), behavioral functions of honeybees were tested on day 12. Fipronil, used at the dose of 0.1 ng/bee, induced mortality of all honeybees after one week of treatment. As a result of contact treatment at 0.01 ng/bee, honeybees spent significantly more time immobile in an open-field apparatus and ingested significantly more water. In the olfactory conditioning paradigm, fipronil-treated honeybees failed to discriminate between a known and an unknown odorant. Thiamethoxam by contact induced either a significant decrease of olfactory memory 24 h after learning at 0.1 ng/bee or a significant impairment of learning performance with no effect on memory at 1 ng/bee. Responsiveness to antennal sucrose stimulation was significantly decreased for high sucrose concentrations in honeybees treated orally with thiamethoxam (1 ng/bee). The only significant effect of acetamiprid (administered orally, 0.1 μg/bee) was an increase in responsiveness to water. The neonicotinoids acetamiprid and thiamethoxam tested at the highest dose (one-tenth and one-fifth of their oral LD50, respectively) and fipronil at one-five-hundredth of LD50 have limited effects on the motor, sensory, and cognitive functions of the honeybee. Our data on the intrinsic toxicity of the compounds after chronic exposure have to be taken into account for evaluation of risk to honeybees in field conditions.
Buoyant Filter Bio-Reactor (BFBR)–a novel anaerobic wastewater treatment unit
Authors: Panicker Soosan J. , Philipose M. C. , Haridas Ajit
Published: August 2008

The Buoyant Filter Bio-Reactor (BFBR) is a novel and very efficient method for the treatment of complex wastewater. Sewage is a complex wastewater containing insoluble COD contributed by fat and proteins. The fat and proteins present in the domestic sewage cause operational problems and underperformance in the Upflow Anaerobic Sludge Blanket Reactor, used now for treating sewage anaerobically. The biogas yield from the BFBR is 0.36 m3/kg COD reduced and the methane content was about 70–80%. Production of methane by anaerobic digestion of organic waste had the benefit of lower energy costs for treatment and is thus environmentally beneficial to the society by providing a clean fuel from renewable feed stocks. The BFBR achieved a COD removal efficiency of 80–90% for an organic loading rate of 4.5 kg/m3/d at a hydraulic retention time of 3.25 hours. The effluent COD was less than 100 mg/l, thus saving on secondary treatment cost. No pretreatment like sedimentation was required for the influent to the BFBR. The BFBR can produce low turbidity effluent as in the activated sludge process (ASP). The land area required for the BFBR treatment plant is less when compared to ASP plant. Hence the problem of scarcity of land for the treatment plant is reduced. The total expenditure for erecting the unit was less than 50% as that of conventional ASP for the same COD removal efficiency including land cost.