bluuebunny/crossref_metadata_2025_split huggingface dataset:
Looking for the Iberian lynx in central Spain: a needle in a haystack?
Authors: Alda F. , Inogés J. , Alcaraz L. , Oria J. , Aranda A. , Doadrio I. 
Published: July 2008

AbstractThe Iberian lynx Lynx pardinus has suffered a dramatic reduction in its range throughout the Iberian Peninsula and at present is one of the most endangered mammals in the world. The latest studies report that, out of the 48 breeding areas that existed in 1990, only two populations are left in southern Spain. As a consequence, some of the formerly largest populations, such as Montes de Toledo (central Spain), are to all intents and purposes regarded as extinct. To determine the current distribution of Iberian lynx outside the two recognized populations, we surveyed five different areas where the species is considered extinct and collected 581 faeces for the genetic identification of the species. We identified 18 samples as belonging to Iberian lynx in four out of the five areas studied, providing clear evidence for the presence of lynx in central Spain. In some areas the species was detected repeatedly at different localities and on different dates, indicating a regular occurrence of an unknown number of individuals. The conservation implications of these results are discussed in terms of the genetic importance of the individuals found and future reintroductions of the species from an ongoing captive‐breeding programme.
Microsatellite DNA analysis of success in conserving genetic diversity after 33 years of refuge management for the desert pupfish complex
Authors: Koike H. , Echelle A. A. , Loftis D. , Van Den Bussche R. A. 
Published: July 2008

AbstractRefuge populations of Cyprinodon macularius and Cyprinodon eremus, the extant members of the endangered desert pupfish complex, have been maintained for up to 33 years in semi‐natural refuges. We examined the success of the refuge program in maintaining diversity at four microsatellite DNA loci in 24 refuge populations of C. macularius and six of C. eremus that include, respectively, seven and four lineages representing original translocations from the wild. These lineages have been maintained with essentially no inoculations of genetic material from the wild and, except for one refuge, no intermixing of lineages. Comparison with wild‐source populations showed marked declines in diversity within local refuges and within lineages, but relatively minor declines for the composite of all refuge populations for each species. In genetic makeup, the refuge populations generally clustered by lineage, indicating significant genetic drift early in lineage history. The results indicate that, with relatively minor adjustments in management, the refuge program can successfully preserve a large portion of the wild genetic diversity in the desert pupfish complex.
Adult stem cell maintenance and tissue regeneration in the ageing context: the role for A‐type lamins as intrinsic modulators of ageing in adult stem cells and their niches
Authors: Pekovic Vanja , Hutchison Christopher J. 
Published: July 2008

AbstractAdult stem cells have been identified in most mammalian tissues of the adult body and are known to support the continuous repair and regeneration of tissues. A generalized decline in tissue regenerative responses associated with age is believed to result from a depletion and/or a loss of function of adult stem cells, which itself may be a driving cause of many age‐related disease pathologies. Here we review the striking similarities between tissue phenotypes seen in many degenerative conditions associated with old age and those reported in age‐related nuclear envelope disorders caused by mutations in the LMNA gene. The concept is beginning to emerge that nuclear filament proteins, A‐type lamins, may act as signalling receptors in the nucleus required for receiving and/or transducing upstream cytosolic signals in a number of pathways central to adult stem cell maintenance as well as adaptive responses to stress. We propose that during ageing and in diseases caused by lamin A mutations, dysfunction of the A‐type lamin stress‐resistant signalling network in adult stem cells, their progenitors and/or stem cell niches leads to a loss of protection against growth‐related stress. This in turn triggers an inappropriate activation or a complete failure of self‐renewal pathways with the consequent initiation of stress‐induced senescence. As such, A‐type lamins should be regarded as intrinsic modulators of ageing within adult stem cells and their niches that are essential for survival to old age.
A model of the intracortical vascular system of long bones and of its organization: an experimental study in rabbit femur and tibia
Authors: Pazzaglia Ugo E. , Bonaspetti Giovanni , Ranchetti Federico , Bettinsoli Pierfrancesco 
Published: July 2008

AbstractThe vascular anatomy of the cortical bone and the canal system are highly correlated, and the former has an important bearing on shape and microscopic lamellar structure, as it is established in the progression of the remodelling process. The classical description of a longitudinal system of canals (Havers’) connected by the transversal Volkmann's canals is the generally acknowledged model of the structural organization of the cortex. However, it is remarkably difficult to study the circulation inside the compact bone in detail owing to its hard, calcified matrix, and the methods thus far applied have represented either the bone morphology and the architecture of the canal system or the injected vessel network. In the present study, the intracortical vessel network was injected with black China ink and evidenced by transillumination of full‐thickness, decalcified hemicortices. By making use of the depth of field of the microscope objective, the three‐dimensional architecture of the network was highlighted and the morphometry of vessel size measurements and a classification of the network nodes according to the number of arms was made possible. These observations were integrated with data obtained by routine histology on decalcified sections relevant to the connections of the intracortical canal system with the outer environment, with regard to the direction of advancement of new canals and with regard to the mode of formation of the system nodes. The formation of the intracortical vessels network involved two processes: the incorporation of the periosteal network and osteonal remodelling, the latter occurring through the advancement of cutting cones followed by their own vascular loop and by concentric lamellar apposition. The two systems could be distinguished by the diameter of the vessels (the former were significantly larger) and by the network architecture (the former convoluted, and the latter longitudinally orientated and straight). Longitudinal vessels could form branches or create connections with the periosteal derived vessels that occasionally meet on the line of their advancement. They were observed entering from either inside the cortex from the metaphyses or from the endosteal surface of the marrow cavity. The combined observations from different methods of study documented a model of intracortical canal and vessel networks formed by two initially independent systems: one derived from the external, periosteal vessels, and one from metaphyseal and marrow vessels. Connections between the two were established with the advancing of cutting cones from the extremities of the diaphysis. Analysis of the system architecture and the modalities of its progressive organization suggested that the direction of advancement of a forming canal does not necessarily correspond to the final blood flow direction of its central vessel.
Prenatal and early postnatal morphogenesis and growth of human laryngotracheal structures
Authors: Fayoux Pierre , Marciniak Bruno , Devisme Louise , Storme Laurent 
Published: July 2008

AbstractAdvances in neonatal medicine have resulted in increased care of fetal and neonatal airways. These advances have required an exhaustive knowledge of fetal airway anatomy and development. The aim of this study was to determine the anatomical development of laryngotracheal structures during the fetal and immediate postnatal period and to correlate these observations with other fetal biometric parameters to estimate developmental particularities of the fetal airway. An anatomical prospective study was based on examination of larynx and trachea from 300 routine autopsies of fetuses and infants, free of malformation and never intubated. Anatomical measurements of cricoid cartilage, thyroid cartilage, glottis, arytenoid cartilage and trachea were performed using a precision calliper and precision divider. Statistical analysis was performed to represent the growth of anatomical structures and to evaluate the correlation with biometric data. Raw data and 10th and 90th percentile curves were fitted satisfactorily with a linear model for gestational age. A linear relationship between laryngotracheal measurement and body weight and height was observed except for glottis length, interarytenoid distance and anterior cricoid height. The diameter of the cricoid lumen was significantly less than that of the trachea and glottis lumen. A sexual dysmorphism was noted for thyroid cartilage measurements and interarytenoid distance, with measurements significantly smaller in females. This study reports the anatomical development of normal laryngotracheal structures during the fetal period. Despite the fact that this study was performed during postmortem examination, these observations can be useful to develop criteria, materials and surgical procedures adapted to fetal and neonatal airways as well as for the purposes of early diagnosis and management of laryngotracheal malformations.
Distribution, density and morphology of electroreceptor organs in mormyrid weakly electric fish: anatomical investigations of a receptor mosaic
Authors: Hollmann M. , Engelmann J. , Von Der Emde G. 
Published: July 2008

Abstract Gnathonemus petersii and other African weakly electric fish (Mormyridae) produce electric signals in order to sense their environment, a process called active electrolocation. During active electrolocation electrical images of objects in the environment are cast onto a mosaic of electroreceptors, which are embedded in the animal's skin. In Gn. petersii and four other species of mormyrid fish, the densities of electroreceptor organs (mormyromasts and ampullary organs) were determined at various skin regions, including the chin, the nasal region and the back. In all species investigated, the highest mormyromast densities were found at the chin, followed by the nasal region. In addition to this comparative approach, we investigated the electroreceptive epidermis of Gn. petersii in more detail. At the moveable chin appendix, the Schnauzenorgan, scanning electron microscopy analysis helped to elucidate the mosaic‐like distribution and the morphology of the electroreceptor organs and their embedding in the epidermis. Because the number of mormyromasts increased very little when fish got bigger, receptor organ densities decreased with standard length. Mormyromast density at the Schnauzenorgan, especially at its tip, highly exceeded that at all other skin regions. Along the Schnauzenorgan, receptor densities decreased exponentially from the tip towards the base. At the nasal region, mormyromast densities were more than three times higher compared to the rest of the fish's head and trunk. A similar distribution to that of the mormyromasts was found for the ampullary electroreceptor organs, which are used for passive electroreception. Our findings support the hypothesis that at least in Gn. petersii the Schnauzenorgan and the nasal region are electroreceptive foveae.
Shape analysis of different populations of clams in relation to their geographical structure
Authors: Costa C. , Aguzzi J. , Menesatti P. , Antonucci F. , Rimatori V. , Mattoccia M. 
Published: July 2008

AbstractBivalves are excellent candidates for geographically based studies of the morphological variation in individuals of different populations based on the analysis of their shape profiles. In this study, we quantified the overall shell shape differences in individuals of different populations of Ruditapes decussatus and Ruditapes philippinarum in relation to their geographical and genetic distances. A total of 395 and 124 individuals of R. decussatus (nine populations) and R. philippinarum (four populations), respectively, were sampled in different Mediterranean and Atlantic coastal locations. Pictures of the left valve were taken from all individuals. Their profiles were analysed using elliptic Fourier analysis. Mean outlines were computed. In order to classify different individuals for species, the coefficients of harmonic equations were analysed by partial least square discriminant analysis and soft independent modelling of class analogy. The results showed a high percentage of correct classification (99%) between the two species in the independent test. We found that the morphological distance between R. philippinarum and R. decussatus is higher than the morphological distance among populations of the same species. The absence of correspondence between the geographical location and the pattern of morphological and genetic variation indicates the occurrence of a reaction norm in the morphological adaptation of shell shapes to different local environmental conditions.
Spatio‐temporal sharing between the European wildcat, the domestic cat and their hybrids
Authors: Germain E. , Benhamou S. , Poulle M.‐L. 
Published: July 2008

AbstractThe European wildcat Felis silvestris silvestris, which can hybridize with the domestic cat Felis catus to produce fertile hybrids, is threatened by hybridization. To identify the behavioural processes that can affect interbreeding, we investigated the spatio‐temporal sharing between wildcats, domestic cats and their hybrids (defined on their genotypes) in a rural area of north‐eastern France where hybridization is frequent. Wildcats' and hybrids' home ranges were larger than those of domestic cats, and they did not vary according to body mass, season and reproductive period. The three types of cats had similar daily activity rhythms but the concordance between their space use patterns was low or null. Thus, a high spatio‐temporal concordance is not a prerequisite for hybridization. Rare excursions made by the cats outside of their home ranges may be at the origin of interbreeding. Moreover, hybrids may play a key role in hybridization by behaving as wildcats and by sharing at least a part of their range with them as well as with domestic cats. Behavioural barriers between them and wildcats may not exist because of their similarity in morphology and spatial behaviour.
Anti‐predator behaviour, space use and habitat selection in female roe deer during the fawning season in a wolf area
Authors: Bongi P. , Ciuti S. , Grignolio S. , Del Frate M. , Simi S. , Gandelli D. , Apollonio M. 
Published: July 2008

AbstractThis study investigated the anti‐predator strategies adopted by 19 radio‐collared female roe deer during the fawning season by monitoring their spatial behaviour and habitat selection by means of radio‐tracking. The study was carried out in a forest area of the Apennine Mountains (central Italy), where wolves are natural predators of roe deer and in summer fawns are more frequently predated than adult roe deer. The presence of fawns was monitored by means of direct observations. Roe deer fawns are known to adopt the hiding strategy during the lactation period, when they lie concealed for long periods waiting for their mothers' milk. As a consequence of this, the home‐range sizes of mothers were significantly smaller than those of non‐mothers during the summer lactation only. In contrast, no significant difference was found in spring, when fawns were absent, or autumn, when they were already weaned. In order to increase the success of the hiding strategy adopted by their fawns against wolf predation, mothers selected denser habitats (deciduous coppice forests) that provided denser undergrowth vegetation and limited visibility. In doing so, mothers traded open areas for forests throughout the fawning season. Indeed, mothers made significant habitat selection throughout the monitored period, and this was marked after the birth of fawns. In contrast, non‐mothers generally used habitat types according to their availability. During lactation, the correlation between habitat use by mothers and habitat visibility (assessed using the form of a standard‐sized roe deer) was inversely significant. These results taken together highlight the importance of anti‐predator strategies adopted by roe deer mothers during the critical phase for fawn survival.
Negative regulation of neurogenesis and spatial memory by NR2B‐containing NMDA receptors
Authors: Hu Mei , Sun Yong‐Jun , Zhou Qi‐Gang , Chen Ling , Hu Yao , Luo Chun‐Xia , Wu Jia‐Yi , Xu Jin‐Shu , Li Li‐Xin , Zhu Dong‐Ya 
Published: July 2008

AbstractsSeveral lines of evidence suggest involvement of NMDA receptors (NMDARs) in the regulation of neurogenesis in adults and the formation of spatial memory. Functional properties of NMDARs are strongly influenced by the type of NR2 subunits incorporated. In adult forebrain regions such as the hippocampus and cortex, only NR2A and NR2B subunits are available to form the receptor complex with NR1 subunit. NR2B is predominant NR2 subunit in any of rat or human neural stem cells (NSCs). Thus, we suppose that NR2B‐containing NMDAR should be critical in regulating adult neurogenesis, and thereby playing a role in the formation of spatial memory. In the cultured NSCs derived from the embryonic brain of rats, NR2B subunit‐specific NMDAR antagonist Ro25‐6981 increased cell proliferation, whereas MK‐801, non‐selective open‐channel blocker of NMDARs, inhibited cell proliferation. Blockade of NR2B‐containing NMDAR stimulated neurogenesis in the adult hippocampus and facilitated the formation of spatial memory. The enhanced spatial memory dropped back to base level when the NR2B antagonist‐induced neurogenesis was neutralized by 3′‐azido‐deoxythymidine, a telomerase inhibitor. In addition, blockade of NR2B inhibited neuronal nitric oxide synthase (nNOS) enzymatic activity. In null mutant mice lacking nNOS gene (nNOS−/−), the effects of NR2B antagonist on neurogenesis disappeared. Moreover, nitric oxide donor DETA/NONOate attenuated and nNOS inhibitor 7‐nitroindazole enhanced the effect of Ro 25‐6981 on NSCs proliferation. Our findings suggest that NR2B‐containing NMDAR subtypes negatively regulate neurogenesis in the adult hippocampus by activating nNOS activity and thereby hinder the formation of spatial memory.
Identification and characterization of a novel, shorter isoform of the small conductance Ca2+‐activated K+ channel SK2
Authors: Murthy Saravana R. K. , Teodorescu Georgeta , Nijholt Ingrid M. , Dolga Amalia M. , Grissmer Stephan , Spiess Joachim , Blank Thomas 
Published: July 2008

AbstractThroughout the CNS, small conductance Ca2+‐activated potassium (SK) channels modulate firing frequency and neuronal excitability. We have identified a novel, shorter isoform of standard SK2 (SK2‐std) in mouse brain which we named SK2‐sh. SK2‐sh is alternatively spliced at exon 3 and therefore lacks 140 amino acids, which include transmembrane domains S3, S4 and S5, compared with SK2‐std. Western blot analysis of mouse hippocampal tissue revealed a 47 kDa protein product as predicted for SK2‐sh along with a 64 kDa band representing the standard SK2 isoform. Electrophysiological recordings from transiently expressed SK2‐sh revealed no functional channel activity or interaction with SK2‐std. With the help of real‐time PCR, we found significantly higher expression levels of SK2‐sh mRNA in cortical tissue from AD cases when compared with age‐matched controls. A similar increase in SK2‐sh expression was induced in cortical neurons from mice by cytokine exposure. Substantial clinical evidence suggests that excess cytokines are centrally involved in the pathogenesis of Alzheimer’s disease. Thus, SK2‐sh as a downstream target of cytokines, provide a promising target for additional investigation regarding potential therapeutic intervention.
Expression of Kv1.2 in microglia and its putative roles in modulating production of proinflammatory cytokines and reactive oxygen species
Authors: Li Fan , Lu Jia , Wu Chun‐Yun , Kaur Charanjit , Sivakumar Viswanathan , Sun Jun , Li Shuqing , Ling Eng‐Ang 
Published: July 2008

AbstractMicroglial cells are endowed with different potassium ion channels but their expression and specific functions have remained to be fully clarified. This study has shown Kv1.2 expression in the amoeboid microglia in the rat brain between 1 (P1) and 10 (P10) days of age. Kv1.2 expression was localized in the ramified microglia at P14 and was hardly detected at P21. In postnatal rats exposed to hypoxia, Kv1.2 immunoreactivity in microglia was markedly enhanced. Quantitative RT‐PCR analysis confirmed Kv1.2 mRNA expression in microglial cellsin vitro. It was further shown that Kv1.2 and protein expression coupled with that of interleukin 1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α) was significantly increased when the cells were subjected to hypoxia. The same increase was observed in cells exposed to adenosine 5′‐triphosphate (ATP) and lipopolysaccharide (LPS). Concomitantly, the intracellular potassium concentration decreased significantly. Blockade of Kv1.2 channel with rTityustoxin‐Kα (TsTx) resulted in partial recovery of intracellular potassium concentration accompanied by a reduced expression of IL‐1β and TNF‐α mRNA and protein expression and intracellular reactive oxygen species (ROS) production. We conclude that Kv1.2 in microglia modulates IL‐1β and TNF‐α expression and ROS production probably by regulating the intracellular potassium concentration.
P2Y1receptor‐mediated glutamate release from cultured dorsal spinal cord astrocytes
Authors: Zeng Jun‐Wei , Liu Xiao‐Hong , Zhang Jin‐Hai , Wu Xi‐Gui , Ruan Huai‐Zhen 
Published: July 2008

AbstractP2 receptors have been implicated in the release of neurotransmitter and proinflammatory cytokines by the response to neuroexcitatory substances in astrocytes. In the present study, we examined the mechanisms of ADP and adenosine 5′‐O‐2‐thiodiphosphate (ADPbetaS, ADP analogue) on glutamate release from cultured dorsal spinal cord astrocytes by using confocal laser scanning microscopy and HPLC. Immunofluorescence activity showed that P2Y1receptor protein is expressed in cultured astrocytes. ADP and ADPbetaS‐induced [Ca2+]iincrease and glutamate release are mediated by P2Y1receptor. Ca2+release from IP3‐sensitive calcium stores and protein kinase C (PKC) activation is important for glutamate release from astrocytes. Furthermore, P2Y1receptor‐evoked glutamate release is regulated by volume‐sensitive Cl−channels and anion co‐transporter, which open up the possibility that P2Y1receptor activation causes the increase of cell volume. Release of glutamate by ADPbetaS was abolished by 5‐nitro‐2 (3‐phenyl propy lamino)–benzoate plus furosemide but was unaffected by botulinum toxin A. These observations indicate that P2Y1receptor‐evoked glutamate may be mediated via volume‐sensitive Cl−channel but not via exocytosis of glutamate containing vesicles. We speculate that P2Y1receptors‐evoked glutamate efflux, occurring under pathological condition, may modulate the activity of synapses in spinal cord.