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Distribution Patterns (distribution + pattern)
Kinds of Distribution Patterns Selected AbstractsANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELDINSECT SCIENCE, Issue 4 2004Zhi Wang Abstract The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively. [source] DO PHYSICAL FACTORS REGULATE PHYTOPLANKTON DISTRIBUTION PATTERNS IN LARGE, SHALLOW LAKES?JOURNAL OF PHYCOLOGY, Issue 2000H.J. Carrick Factors that regulate phytoplankton dynamics in shallow, productive lakes are poorly understood, due to their predisposition for frequent algal blooms and sediment resuspension events. In Lake Apopka, greatest phytoplankton biomass reflects wind-induced resuspension of algae (meroplankton) that exists on the aphotic lake bottom in a layer approximately 5 cm thick; this assemblage is dominated by diatoms (>60% of total biomass) that can occur in resting stages. Once exposed to moderate light, meroplankton are capable of growth and photosynthetic rates comparable with surface populations. In Lake Okeechobee, remote sensing was used to assess the basin-wide distribution of suspended particles. Satellite reflectance values agreed well with in situ particle densities at 20 in-lake stations (average r2; LANDSAT = 0.81, AVHRR = 0.53), and maps of algal blooms (r2 = 0.79, p , 0.01). The greatest chlorophyll concentrations occurred in the vicinity of tributary nutrient inputs at the lake's perimeter, while turbidity increased towards the center of the lake reflecting predominant water circulation patterns. These results underscore the importance of physical-biological interactions in lakes. [source] Distribution Pattern of Neuropeptide Y in the Brain, Pituitary and Olfactory System during the Larval Development of the Toad Rhinella arenarum (Amphibia: Anura)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009T. Heer Summary The first NPY-immunoreactivity (ir) in the central nervous system of Rhinella arenarum was obtained just after hatching in the pre-optic area, ventral thalamus and rostral rhombencephalon. During pre-metamorphosis, new NPY-ir cells were observed in other brain areas such as pallium, septum and striatum, infundibulum and pars intermedia of the pituitary. Further maturation continued through pro-metamorphosis with the appearance of cell groups in the diagonal band, amygdala, pre-optic nucleus, dorsal nucleus of the habenula, anterior ventral and dorsal thalamus, suprachiasmatic nucleus, tuberculum posterior, tectum, torus semicircularis, inter-peduncular nucleus and median eminence. During the metamorphic climax and soon after, the relative abundance of NPY-ir fibres decreased in all hypothalamic areas and the staining intensity and number of NPY-ir cells in the pallium also decreased, whereas no cells were found in the striatum, dorsal nucleus of the habenula and tectum. In the olfactory epithelium, nerve or bulb, neither cells nor NPY-ir fibres were found during the stages of development analysed. The ontogeny pattern of the NPY-ir neuronal system in the brain of Rh. arenarum is more similar to the spatiotemporal appearance reported for Rana esculenta than to that reported for Xenopus laevis. Many NPY-ir fibres were found in the median eminence and in the pars intermedia of the pituitary, supporting the idea that this neuropeptide may play a role in the modulation of hypophyseal secretion during development. [source] Spatial Distribution Patterns of Jumping Spiders Associated with Terrestrial BromeliadsBIOTROPICA, Issue 4 2004Gustavo Q. Romero ABSTRACT The jumping spiders Eustiromastix native, Psecas sumptuosus, and Uspachus sp. n. (Salticidae) live on terrestrial bro-meliads in areas with different phytophysiognomies in southeastern and northeastern Brazil. To understand these spider,plant interactions, we investigated if (1) these spiders were associated specifically with bromeliads, (2) the spiders utilized particular bromeliad species, and (3) plant size and density of bromeliads affected spider distribution. The jumping spiders were not found outside bromeliads, indicating a strict spider,plant association. Eustiromastix and Uspachus occupied bromeliads in open areas, whereas Psecas was found on forest bromeliads. Eustiromastix occurred at a higher frequency on larger bromeliads and in patches with higher bromeliad density. This is one of the few studies to demonstrate specific relationships between jumping spiders and a particular plant type. RESUMO As aranhas saltadoras Eustiromastix native, Psecas sumptuosus e Uspachus sp. n. (Salticidae) vivem sobre bromélias terrestres em áreas com diferentes fitofisionomias no sudeste e nordeste do Brasil. Para compreender estas interaçóes aranha-planta, nós investigamos se (1) estas aranhas estavam associadas especificamente a bromélias, (2) as aranhas utilizam espécies particulares de bromélias e (3) tamanho e densidade das bromélias afetam a distribuiçáo das aranhas. As aranhas saltadoras não foram encontradas fora das bromélias, indicando uma associaçáo estrita entre aranha e planta. Eustiromastix e Uspachus ocuparam bromelias em areas abertas enquanto Psecas foi encontrada em bromélias de floresta. Eustiromastix ocorreu em maior freqüéncia sobre bromélias maiores e em manchas com maior densidade de bromélias. Este estudo é um dos poucos a demonstrar relaço,es especificas entre aranhas saltadoras e um tipo particular de planta. [source] Distribution Patterns of Migrant and Resident Birds in Successional Forests of the Yucatan Peninsula, Mexico,BIOTROPICA, Issue 1 2001Andrea L. Smith ABSTRACT Increasing human activity in the Yucatan peninsula has led to declines in older stages of successional forest, threatening regional habitat diversity. To determine potential effects of this habitat loss on the region's avifauna, we examined the relative use of different forest stages by resident and migrant birds during the nonbreeding season. We used the fixed-width transect method to compare the distribution, abundance, and diversity of forest birds in early (five to ten years old), mid (15,25 years), and late (<50 years) successional forests in the state of Campeche, Mexico, in the south-central part of the peninsula. All stages of successional forest had highly similar bird assemblages and did not differ in bird abundance or diversity. Both migrant and resident birds occurred across the successional gradient. The majority of habitat specialists, however, were resident birds restricted to late-successional forest, indicating that early secondary growth may not be suitable for all species. Furthermore, resident birds that typically participate in mixed-species flocks attained their greatest densities in the oldest forest habitat. Rapid recovery of pre-disturbance physiognomic features, in addition to high levels of habitat connectivity in the region, may contribute to similar bird communities across a range of successional stages. The high degree of edge characterizing much of the forest mosaic also may allow birds access to different serai stages. Loss of late-successional forest, however, is likely to adversely affect the subset of resident avifauna that depends on unique features of mature habitat such as snags, large trees, and climatic buffering. Conservation efforts in Campeche should focus on the specialized requirements of the most habitat-restricted species while preserving the current landscape mosaic characteristic of the small-scale shifting cultivation system. RESUMES El aumento de la actividad humana en el uso del suelo en la Peninsula de Yucatán, ha resultado en la disminución de la regeneración de la selva a etapas más maduras de sucesión, amenazando la diversidad regional de habitats. Para determinar los efectos de esta pérdida sobre la avifauna de la región, estudiamos el uso de diferentes etapas de sucesión de la selva por aves residentes y migratorias durante la temporada no reproductiva. Usamos el método de transecto linear de anchura fija para comparar la distributión, abundancia y diversidad de aves en vegetaclón sucesional (acahuales) de diferentes edades, incluyendo acahual joven (cinco a diez años de edad), acahual de edad media (15-25 afios) y selva (>50 afios) en el sur del estado de Campeche, Mexico. Diferentes etapas de sucesión de la selva tuvieron composition de aves muy similares y no variaron en la abundancia y la diversidad. Tanto las especies migrantes como residentes, estuvieron presentes a travél del gradiente sucesional. Sin embargo, la mayoría de los especialistas fueron aves residentes restingidas a etapas más viejas de sucesión de selva, indicando que la vegetatión sucesional temprana no es favorable para todas las especies. En adicion, las aves residentes que tipicamente participan en bandadas mixtas tuvieron sus densidades más altas en la selva de mayor edad de sucesión. La rápida recuperatión de la selva a sus caracteristicas de estado primario, en adición al alto grado de conectividad de habitat en la región, puede permitir a muchas especies nativas encontrarse en diferentes etapas de vegetatión sucesional. El alto grado de efecto de borde que caracteriza la mayor pane del mosaico de bosque tambíen puede permitir a las aves el acceso a los diferentes tipos de vegetación sucesional. Sin embargo, la pérdida de selva en etapa más madura de sucesión, probablemente rendrá un efecto más adverso sobre el grupo de aves residentes que depende de características únicas de selva madura, tales como árboles secos, árboles grandes y amortiguamiento climático. Los esfuerzos de conservatión deberían enfocarse sobre las especies sensibles con requerimientos especializados de hábitat, preservando selva nativa a la vez que las características actuates de mosaico del paisaje, manteniendo las actividades de roza-tumba y quema a pequena escala. [source] Seasonal dynamics of the hepatotoxic microcystins in various organs of four freshwater bivalves from the large eutrophic lake Taihu of subtropical China and the risk to human consumptionENVIRONMENTAL TOXICOLOGY, Issue 6 2005Jun Chen Abstract So far, little is known on the distribution of hepatotoxic microcystin (MC) in various organs of bivalves, and there is no study on MC accumulation in bivalves from Chinese waters. Distribution pattern and seasonal dynamics of MC-LR, -YR and -RR in various organs (hepatopancreas, intestine, visceral mass, gill, foot, and rest) of four edible freshwater mussels (Anodonta woodiana, Hyriopsis cumingii, Cristaria plicata, and Lamprotula leai) were studied monthly during Oct. 2003,Sep. 2004 in Lake Taihu with toxic cyanobacterial blooms in the summer. Qualitative and quantitative determinations of MCs in the organs were done by LC,MS and HPLC. The major toxins were present in the hepatopancreas (45.5,55.4%), followed by visceral mass with substantial amount of gonad (27.6,35.5%), whereas gill and foot were the least (1.8,5.1%). The maximum MC contents in the hepatopancreas, intestine, visceral mass, gill, foot, and rest were 38.48, 20.65, 1.70, 0.64, 0.58, and 0.61 ,g/g DW, respectively. There were rather good positive correlation in MC contents between intestines and hepatopancreas of the four bivalves (r = 0.75,0.97, p < 0.05). There appeared to be positive correlations between the maximum MC content in the hepatopancreas and the ,13C (r = 0.919) or ,15N (r = 0.878) of the foot, indicating that the different MC content in the hepatopancreas might be due to different food ingestion. A glutathione (GSH) conjugate of MC-LR was also detected in the foot sample of C. plicata. Among the foot samples analyzed, 54% were above the provisional WHO tolerable daily intake (TDI) level, and the mean daily intakes from the four bivalves were 8,23.5 times the TDI value when the bivalves are eaten as a whole, suggesting the high risk of consuming bivalves in Lake Taihu. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 572,584, 2005. [source] Distribution pattern of endangered bird species in ChinaINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2006Fumin LEI Abstract In this study, we determined six "hotspots" for avian biodiversity conservation in China. We analyzed the distribution patterns of 183 threatened bird species in China in conjunction with geographical data to produce a distribution map that shows the concentrations of threatened species. The six biodiversity hotspots are: the western Tianshan Mountains; the Qilian and Hengduan mountains; southern Anhui, southern Jiangsu, and the Zhejiang Hills; the Songliao Plain and the northern region of the North China Plain; the island of Taiwan; and the island of Hainan. Based on our analysis of a species,habitat matrix, species were determined to be distributed mainly in broadleaved forest, grassland and meadows, urban and agricultural areas, wetlands, and bush. Most species were commonly found to have a range of three to five different habitat types. Apart from the six biodiversity hotspots, six ecological clusters were determined. Protection strategies indicating different levels of habitat priority among the biodiversity hotspots were also recommended. [source] Survivin in esophageal cancer: An accurate prognostic marker for squamous cell carcinoma but not adenocarcinomaINTERNATIONAL JOURNAL OF CANCER, Issue 7 2006Antonio Rosato Abstract We quantified the expression of survivin, both as mRNA in real-time PCR and protein in immunohistochemistry, in tumor samples of 112 patients with esophageal cancer (56 squamous cell carcinomas and 56 adenocarcinomas). Overall survival of squamous cell carcinoma patients with high survivin mRNA levels was significantly less than that of patients with low survivin mRNA levels (p = 0.0033). Distribution pattern of survivin (nuclear vs. cytoplasmic or mixed) was not correlated to survival, while the extent of immunostaining was significantly correlated to survivin mRNA values (p = 0.016) and had prognostic relevance in univariate analysis (p = 0.0012). Cox's proportional-hazard regression model showed that tumor survivin expression in esophageal squamous cell carcinoma was the most important prognostic factor, independent of tumor stage and other histopathological factors, both as mRNA relative value (p = 0.0259) and protein immunostaining (p = 0.0147). In esophageal adenocarcinoma, survivin expression and pattern of distribution had no prognostic relevance. Thus, quantifying survivin expression provides a prognostic marker only for esophageal squamous tumors. © 2006 Wiley-Liss, Inc. [source] Distribution pattern of versican, link protein and hyaluronic acid in the rat jreiodontal ligament during exjreimental tooth movementJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2002R. Sato The ability of the jreiodontal ligament (PDL) to rapidly remodel is the basis of orthodontic tooth movement. During the tooth movement, matrix proteoglycans (PGs) may play important roles in spatial, mechanical and biological aspects for the maintenance and repair of the PDL. The aim of this study was to characterize the distribution of a large hyaluronic acid (HA)-binding proteoglycan, versican, link protein (LP) and HA in the rat molar PDL during exjreimental tooth movement by histochemical and immunohistochemical methods. Exjreimental tooth movement was jreformed according to Waldo's method. Histologically, regressive changes, such as decrease of fibroblasts and collagen fibers and exudative change of edema were observed in the compressive side and progressive changes, such as proliferation of fibroblasts and collagen fibers, in the strain side one day after treatment. By 3 days after tooth movement, regressive or progressive changes were not observed in either side. Using monoclonal antibodies specific to versican core protein or LP, the positive immunoreactivity for both molecules was constantly observed throughout the PDL. After the exjreimental force was applied to the tooth, however, the immunostainings of versican and LP became significantly intense only in the compressive side but decreased in the strain side. The intensity in the compressive side was strongest one day after the force was applied and gradually diminished thereafter. HA of both sides did not change during exjreimental tooth movement. Since HA is present in the PDL, large amounts of versican and LP expressed in the compressive side may create large hydrated aggregates via their association with HA that dissipates the compressive force applied to this tissue. [source] Distribution patterns of the Q and B biotypes of Bemisia tabaci in the Mediterranean Basin based on microsatellite variationENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2007B. Simón Abstract At least five of the biotypes described in the Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) complex are known to be present in the Mediterranean Basin area. Only two of them, however, are economically relevant, that is, biotypes B and Q. Biological and genetic differences between the two biotypes have been well studied, but less is known about their patterns of genetic variation and population structure. To address these issues, a study was undertaken based on variation at six microsatellite loci among a subset of nine B. tabaci populations (five belonging to the Q and four to the B biotype). The data obtained show that (i) these loci showed considerable polymorphism in the Q and B biotypes populations although the presence of null alleles can obscure the picture; (ii) the Iberian-Q, Canarian-Q, and Egyptian-B populations exhibit heterozygosity excess as a result of bottleneck events; (iii) the low genetic differentiation between the Israeli, Iberian Peninsula, and Italian populations suggest that these populations share a common gene pool; (iv) the genetic distances between the Canarian-Q population and the geographically close population from Morocco indicates spatial isolation and a limited gene flow; and finally (v) the microsatellite data for the B populations indicate that the whiteflies from Egypt and Israel have a close phylogenetic relationship, but the source of these biotype B invasions into the Mediterranean area remains unknown. [source] Distribution patterns of fish biomass by acoustic survey in three Tunisian man-made lakesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2010I. Djemali Summary In order to test the hypothesis that fish distribution is related to water depth, three exploited reservoirs were sampled at day and at night using a Simrad EK60 echosounder. Acoustic surveys were carried out between February and June 2008, which focused on the fish size, species density (fish per ha) and biomass (kg ha,1) along vertical and longitudinal gradients. It was evident in the surface layer (0,3 m) during daytime that the larger fish sizes occupy waters near the dam or the middle of Lakhmess and Sejnane reservoirs. In the upper layer at nighttime, a gradient of fish size is shown proportional to the depth at Lakhmess Reservoir and inversely proportional at the man-made Sejnane Lake. At Lakhmess and Laabid reservoirs, fish density was significantly higher in deep water (3926 ± 1409 and 624 ± 258 fish per ha) rather than in the upper layer (988 ± 2 and 8 ± 2 fish per ha in daytime, respectively), while at Sejnane Reservoir the number of fish per area was similar along the vertical gradient. The biomass was significantly higher in waters deeper than 3 m at Sejnane Reservoir whereas at Lakhmess it was higher in the surface layer. Fish biomass increased from upstream (0.16 ± 0.05 kg ha,1) to middle (3.07 ± 2.96 kg ha,1) and downstream (3.82 ± 2.30 kg ha,1 at night) areas in the man-made Laabid Lake while a similar longitudinal gradient occurred in the deepest Sejnane Reservoir. The vertical gradient in fish distribution is discussed. From the dam to the tributary of the entire water column, it was concluded that fish biomass distribution was governed by depth and was most abundant in areas with deep waters. [source] Disjunct distributions in Gerris species (Insecta: Hemiptera: Gerridae): an analysis based on spatial and taxonomic patterns of genetic diversityJOURNAL OF BIOGEOGRAPHY, Issue 1 2010M.-C. Gagnon Abstract Aim, To perform a comparative analysis of distribution and genetic diversity in three closely related water strider species (Gerris) in order to shed light on a putative disjunct distribution in Gerris gillettei. Location, Canada and the western United States. Methods, Entomological collections from Canada and the United States were surveyed for records of Gerris pingreensis, G. gillettei and Gerris incognitus in order to establish the distribution range of each species. Using samples from present populations, mitochondrial and nuclear DNA sequence variation were used to construct minimum-spanning networks. Distribution patterns and genetic diversity were then compared among species. Results, Our results showed that G. incognitus is a genetically distinct species with an unsuspected disjunct distribution. Gerris pingreensis and G. gillettei were found to share genetic polymorphism and they displayed spatial differences only in terms of haplotype distribution, suggesting that they form a single species. Main conclusions, Distributional and molecular information uncover unusual distribution patterns and underline taxonomic uncertainty in a group of three closely related Gerris species. Vicariance and failure to recolonize following the last glaciation could explain the G. incognitus disjunction. Morphological and DNA-based species identifications suggest different post-glacial recolonization processes for G. pingreensis and G. gillettei. The putative discontinuous range of G. gillettei may be explained as disjunct phenotypes of a single species. [source] Upregulation of P-cadherin expression in the lesional skin of pemphigus, Hailey-Hailey disease and Darier's diseaseJOURNAL OF CUTANEOUS PATHOLOGY, Issue 6 2001Megumi Hakuno Background: Autoimmune blistering diseases, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), are known to be caused by binding of autoantibodies to the desmosomal cadherins, desmoglein 3 and desmoglein 1, respectively. Recently, mutations in the genes coding Ca2+ pumps leads to inherited blistering diseases, Hailey-Hailey disease (HHD) and Darier's disease (DD). Cadherins are a family of Ca2+ -dependent cell adhesion molecules and P-cadherin is one of the major cadherins expressed in the epidermis. Although detailed mechanisms of acantholysis of these blistering diseases have not been fully clarified, abnormal expression of cadherins caused by altered Ca2+ concentration due to the binding of autoantibodies to cell surface or by mutations in Ca2+ pumps is suggested to be involved in mechanisms of acantholysis of these atuoimmune and inherited blistering diseases. The purpose of the present study was to determine whether altered P-cadherin expression is present in these diseases. Method: Distribution patterns of P-cadherin in skin specimens from patients with PV (n=2), PF (n=2), HHD (n=4) and DD (n=3), were examined with confocal laser scanning microscopy using two anti-P-cadherin antibodies, 6A9 and NCC-CAD-299. Results: In normal control skin, P-cadherin expression was restricted to the basal layer. In contrast, positive immunostaining of P-cadherin was observed not only in the basal cells, but also in the suprabasal cells in lesional skin of all the acantholytic diseases. Conclusions: The present results clearly demonstrated that upregulation of P-cadherin expression occurs in the acantholysis in all the four blistering diseases PV, PF, HHD and DD. Upregulation of P-cadherin may be involved in the pathomechanism of both the autoimmune blistering diseases and the inherited blistering diseases. [source] The relative importance of dispersal limitation of vascular plants in secondary forest succession in Muizen Forest, BelgiumJOURNAL OF ECOLOGY, Issue 5 2001Kris Verheyen Abstract 1,Distribution patterns (frequency and percentage cover) of 18 forest plant species were studied in 34 ha of mixed deciduous forest (Muizen Forest, north Belgium). Stands varied in age between 6 and more than 223 years and both slow and fast colonizing species were studied. 2,Detailed land use history data were combined with the species distribution maps to identify species-specific colonization sources and calculate colonization distances. 3,A multiple logistic regression model was constructed with four covariables: pH (which can impose limits on the potential species-distribution), secondary forest age, distance from nearest colonization source and age,distance interaction, to allow us to account for the gradual completion of colonization over time. 4,We could distinguish species which are limited by both dispersal and recruitment (Primula elatior, Arum maculatum and Lamium galeobdolon), mainly by dispersal (Anemone nemorosa, Deschampsia cespitosa), mainly by recruitment (Paris quadrifolia and Polygonatum multiflorum) and by neither (Geum urbanum, Ranunculus ficaria, Glechoma hederacea, Aegopodium podagraria, Ajuga reptans, Adoxa moschatellina and Oxalis acetosella). 5,The low colonizing capacity of ancient forest plants cannot be attributed to a single cause; rather both dispersal and recruitment are limiting but the relative importance varies. [source] Distribution patterns of ,- and ,-herpesviruses within Waldeyer's ring organsJOURNAL OF MEDICAL VIROLOGY, Issue 8 2007Christoph Berger Abstract The Waldeyer's ring designates a functional unit of lymphoid tissue within the pharynx including the adenoids and tonsils. To gain insight into distribution patterns of ,- and ,-human herpesviruses (HHVs) and their potential mutual influences at their natural portal of entry, quantitative polymerase chain reaction (qPCR) assays were applied to adenoids and tonsils obtained from 30 children. DNA of Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6, HHV-7, and HHV-8 was detected in adenoids, tonsils, or both of 24 (80%), 19 (63%), 23 (77%), 23 (77%), and 0 (0%) children, respectively. EBV, CMV, HHV-6, and -7 localized in both adenoids and tonsils from 92%, 37%, 52%, and 70% of children, respectively, with the virus detectable by qPCR. The amount of EBV was 2,10-fold higher than of other HHVs and correlated in autologous organs (P,=,0.01) as did the amount of HHV-7 (P,=,0.002). The amount of CMV correlated with the HHV-6 amount in adenoids (P,=,0.028) and tonsils (P,=,0.007), and with the amount of HHV-7 in adenoids (P,<,0.01). Levels of HHV-6 DNA were lower in adenoids with detectable CMV DNA than in adenoids without detectable CMV DNA (P,=,0.0062). Inversely, CMV and HHV-7 levels were higher in adenoids with than in adenoids without detectable EBV DNA (P,=,0.019 and P,=,0.039, respectively).Thus, ,- and ,-HHV exhibit distinct distribution behaviors in Waldeyer's ring organs and seem to interact. This may be of medical importance in immunocompromised hosts who are likely to reactivate HHVs causing severe morbidity and death. J. Med. Virol. 79: 1147,1152, 2007. © 2007 Wiley-Liss, Inc. [source] Arsenic pollution of groundwater in Bangladesh,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2001Kimiko Tanabe Abstract Arsenic concentrations in groundwater around the village of Samta, Jessore District, Bangladesh were measured. Distribution patterns of arsenic in groundwater were determined. Arsenic concentrations in drinking water tubewells mostly exceeded WHO guidelines. Copyright © 2001 John Wiley & Sons, Ltd. [source] The relation between the localization of foot dermatitis and the causative allergens in shoes: a 13-year retrospective studyCONTACT DERMATITIS, Issue 4 2005A. Nardelli The purpose of this retrospective study was to test whether the initial pattern of clinical presentation of shoe dermatitis could indicate the causative allergen(s) and to estimate the odds on foot dermatitis in patients with a positive patch test versus those with a negative patch-test result. Between 1990 and 2002, 8543 patients were patch tested with the standard series (and additional allergens, if appropriate). Of them, 1168 (14%) had been referred because of foot dermatitis and 474 of these patients (5.5% of the total group) presented a positive reaction to one or more substances related to shoes. We found that 6 standard allergens in the male group and 8 standard allergens in the female group were statistically significant for the shoe dermatitis group. The data showed a relationship between the distribution pattern of the foot lesions and most of the allergens. These results have clinical applications since the gender of the patients and the localization of the foot eruptions can, indeed, indicate what allergen is involved. [source] Synthetic matrix metalloproteinase inhibitor decreases early cardiac neural crest migration in chicken embryosDEVELOPMENTAL DYNAMICS, Issue 4 2002D.H. Cai Abstract During early embryonic development, cardiac neural crest (NC) cells emerge from the forming neural tube, migrate beneath the ectoderm, enter the pharyngeal arches, and subsequently participate in the septation of the heart. Like tumor cells, NC cells penetrate through basement membranes and invade extracellular matrix during their emigration and migration and, therefore, are liable to use similar invasive mechanisms. Matrix metalloproteinases (MMPs) are a family of zinc proteolytic enzymes known to be important in cell migration and invasion of normal and metastatic cells. In an earlier study, we found that the spatial and temporal distribution pattern of MMP-2 positively correlates with cardiac NC migration, suggesting MMP enzymatic activity may be important in mediating cardiac cell NC migration. To test this hypothesis, a synthetic MMP inhibitor, KB8301, was used to block MMP enzymatic activity during in vitro and in vivo cardiac NC cell migration in chick embryos. Injection of KB8301 into the cell-free space adjacent to the neural tube at the level of the second somite before the NC cells emigrated caused major morphologic anomalies in embryos and disrupted cardiac NC morphogenesis. Unilateral injection of KB8301 at lower concentrations, significantly decreased cardiac NC migration on the injected side compared with the noninjected side and compared with that of the injected controls. This decrease correlated with a decrease in MMP activity in the embryos and was not attributable to differences in embryo size or rate of embryonic development after injection. KB8301 also significantly decreased the rate of NC cell motility and distance NC cells migrated from explanted neural tubes and increased cell area and perimeter. These data suggest that MMP enzymatic activity is an important mediator of early cardiac NC migration and that perturbation of endogenous MMP activity may lead to NC-related congenital defects. © 2002 Wiley-Liss, Inc. [source] Selective expression of the small GTPase RhoB in the early developing mouse lensDEVELOPMENTAL DYNAMICS, Issue 3 2001Rupalatha Maddala Abstract This report describes the expression and distribution pattern of RhoB GTPase in the developing mouse lens. RhoB expression was confirmed by sequencing an reverse transcriptase-polymerase chain reaction,generated DNA fragment of RhoB. Immunohistochemical analysis of RhoB revealed expression in the lens vesicle (both anterior and posterior vesicle) at embryonic day (E) 11.5, and in the epithelium and primary fibers of the E14.5 lens. Compared with the neonatal stage (day 1), where RhoB is detected in the entire lens (epithelium, primary, and secondary fibers), expression of this protein is restricted to the epithelial and outer cortical secondary fibers in postnatal lenses (from day 7 to day18). Interestingly, in E11.5 and E14.5 lenses, RhoB is localized predominantly in the lens, but not detectable in the retina, cornea, or other ocular tissues. RhoB expression appears to be down-regulated in the postnatal lens with concomitant up-regulation in the retina and cornea, compared with earlier stages of development (eyes of E11.5, E14.5, and neonatal mice). This study reveals the selective expression of RhoB in the lens during early eye development and suggests a potential role for this small GTPase in cytoskeletal reorganization associated with lens epithelial cell elongation and differentiation. © 2001 Wiley-Liss, Inc. [source] Occurrence and distribution of sesamoid bones in squamates: a comparative approachACTA ZOOLOGICA, Issue 3 2010Adriana Jerez Abstract Jerez, A., Mangione, S. and Abdala, V. 2010. Occurrence and distribution of sesamoid bones in squamates: a comparative approach.,Acta Zoologica (Stockholm) 91: 295,305 Sesamoids are defined as skeletal elements that develop within a continuous band of regular dense connective tissue (tendon or ligament) adjacent to an articulation or joint. In this work, we discuss developmental data on two squamate species, provide data on the onset of the squamate sesamoids and the muscles they are associated to. Our results show that Mabuya mabouya and Liolaemus albiceps exhibited rather similar ontogenetic patterns and that the first sesamoids appear in embryos. The ossifying sesamoid timing is different between M. mabouya and L. albiceps, being faster in the former. In adults, we found 41 sesamoids, considering both fore and hindlimbs. We did not find any intrataxonomic differences, or any differences between the right and left side of the specimens in relation to the sesamoid presence. We recognize four types of sesamoids: (1) embedded sesamoids; (2) interosseus sesamoids; (3) glide sesamoids; and (4) supporting sesamoids. A table is included with a preliminary survey of the sesamoid distribution pattern in 10 Squamate clades. [source] Brain distribution of myosin Va in rainbow trout Oncorhynchus mykissACTA ZOOLOGICA, Issue 1 2008Kátia Gisele Oliveira Rancura Abstract This study presents data on myosin Va localization in the central nervous system of rainbow trout. We demonstrate, via immunoblots and immunocytochemistry, the expression of myosin Va in several neuronal populations of forebrain, midbrain, hindbrain and spinal cord. The neuronal populations that express myosin Va in trout constitute a very diverse group that do not seem to have many specific similarities such as neurotransmitters used, cellular size or length of their processes. The intensity of the immunoreactivity and the number of immunoreactive cells differ from region to region. Although there is a broad distribution of myosin Va, it is not present in all neuronal populations. This result is in agreement with a previous report, which indicated that myosin Va is approximately as abundant as conventional myosin II and kinesin, and it is broadly involved in neuronal motility events such as axoplasmatic transport. Furthermore, this distribution pattern is in accordance with what was shown in rats and mice; it indicates phylogenetic maintenance of the myosin Va main functions. [source] Variation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradientsECOGRAPHY, Issue 3 2007Gustaf Granath Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra, F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifertarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km2 area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara, was, on average, 12% (local scale) and 37% (regional scale). In F. rubra, infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina, an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara. These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species. [source] Patch occupancy, population density and dynamics in a fragmented red squirrel Sciurusvulgaris populationECOGRAPHY, Issue 1 2003Goedele Verbeylen We studied population dynamics of red squirrels in a group of small forest fragments, that cover only 6.5% of the total study area (4664 ha) and where distances to the nearest source population were up to 2.2 km. We tested effects of patch size, quality and isolation and supplementary feeding on patch occupation during 1995,99. Larger patches and patches with supplementary feeding had a higher probability of being occupied. No patch <3.5 ha was ever occupied. No effects of isolation were found, suggesting that the forest habitat in the study area is not sufficiently fragmented to influence red squirrel distribution across patches. For medium sized patches (3.7,21 ha), that were occupied some years, there was an increase in patch occupation over the years, even though overall population size tended to decrease. These patches had a high turnover, especially of males. Patches in which the squirrel population went extinct were recolonized within a year. For patches that were at least some years occupied, squirrel density depended on patch quality only. No effects of patch size, isolation and winter temperature on population density were found. These data suggest that in our study area habitat fragmentation has no effect on local squirrel density and that the random sample hypothesis explains the distribution pattern across patches. [source] Dynamics in a butterfly,plant,ant system: influence of habitat characteristics on turnover rates of the endangered lycaenid Maculinea alconECOLOGICAL ENTOMOLOGY, Issue 5 2007JAN CHRISTIAN HABEL Abstract 1.,Maculinea alcon, a myrmecophilic, stenotopic lycaenid butterfly is restricted to wet heathlands, bogs, and nutrient-poor hay meadows. Due to intensification of agriculture and decrease of extensively grazed meadows, many suitable habitats have disappeared and the remaining ones are highly fragmented and deteriorated. 2.,Historical distribution data and a comparison with the present occupation of patches show the decline of this critically endangered butterfly in north-west Germany. Most of the populations in north-west Germany are small and often geographically isolated. 3.,In summer 2002, two-thirds of 77 investigated potential patches were unoccupied as a result of unsuitable habitat structure and habitat fragmentation. 4.,Several habitat parameters were highly significantly correlated with the presence of M. alcon, in particular the distribution pattern of the host plant Gentiana pneumonanthe. Furthermore, butterflies were absent from many patches with an incidence probability below 50% with respect to patch size and isolation. 5.,In the nature reserve Lüneburger Heide, part of the study area, M. alcon populations have been observed since 1995. Typical turnover of local populations could be detected during these years. Extinctions and re-colonisations have stabilised the presence of this species in a metapopulation in this nature reserve. 6.,These data show the importance of different factors on different spatial levels influencing the presence of this endangered butterfly. [source] Sensilla on the External Genitalia of the Carabid Beetle, Carabus (Ohomopterus) dehaanii dehaanii Chaudoir (Coleoptera, Carabidae)ENTOMOLOGICAL RESEARCH, Issue 3 2004Lark KIM ABSTRACT Sensilla on the male and female external genitalia of the carabid beetle, Carabus (Ohomopterus) dehaanii dehaanii Chaudoir, were investigated with scanning electron microscopy. The investigation for female genitalia was conducted on the coxites and styli. As a result, 4 types of sensilla were distinguished. In male, a total of 6 types of sensilla were identified on the aedeagus. The external morphology and distribution pattern of each type of the sensilla in both sexes were described. Results are expected to provide a ground work for future research on the phylogenetic study of the genus Carabus and the comparative ultrastructure or behavior in the carabid beetle. [source] Phylogeography of the leaf beetle Chrysolina virgata in wetlands of Japan inferred from the distribution of mitochondrial haplotypesENTOMOLOGICAL SCIENCE, Issue 4 2004Teiji SOTA Abstract The genetic differentiation among populations of the leaf beetle Chrysolina virgata living in wetlands of Japan was studied based on the sequence data of the mitochondrial cytochrome oxidase subunit I gene region (750 bp). Two distinct lineages of mitochondrial haplotypes were found: one (clade A) consisted of 26 haplotypes distributed over the distribution range of C. virgata between north-east Honshu and Kyushu, whereas the other (clade B) was monotypic and confined to a small region in north-east Honshu where it coexisted with clade A. Nested clade analysis for these haplotypes suggested that range expansion and following differentiation due to isolation by distance might have resulted in the present distribution pattern of the haplotypes in clade A. We discuss the evolutionary process leading to the occurrence of two distinct haplotype clades in Japan in terms of repeated colonization from the continent and range expansion and contraction during climatic changes. [source] Voxel-based T2 Relaxation Rate Measurements in Temporal Lobe Epilepsy (TLE) with and without Mesial Temporal SclerosisEPILEPSIA, Issue 2 2007Susanne G. Mueller Summary:,Introduction: Quantitative measurements of T2 relaxation in the hippocampus for focus lateralization in mesial temporal lobe epilepsy (mTLE) are well established. Less is known to what degree such relaxation abnormalities also affect regions beyond the ipsilateral hippocampus. Therefore, the aim of this study was to characterize extent and distribution pattern of extrahippocampal relaxation abnormalities in TLE with (TLE-MTS) and without MRI evidence of mesial-temporal sclerosis (TLE-no). Methods: Double spin echo images (TE1/2: 20/80 ms) acquired in 24 TLE-MTS and 18 TLE-no were used to calculate relaxation rate maps. These maps were analyzed by SPM2 and by selecting regions of interest (ROI) in the hippocampus and several extrahippocampal brain regions. Results: In TLE-MTS, the results of the SPM and ROI analysis were in good agreement and showed the most severe relaxation rate decreases in the ipsilateral hippocampus but also in other ipsilateral temporal regions, orbitofrontal, and parietal regions and to a lesser degree in contralateral frontal regions. The relaxation rate decreases in TLE-no were confined to small regions in the ipsilateral anterior inferior and medial temporal lobe in the SPM analysis while ROI analysis showed additional regions in the ipsilateral hippocampus, amygdala, and anterior cingulate. Conclusion: TLE-MTS showed extensive, widespread but predominantly ipsilateral temporal and also extratemporal T2 relaxation rate decreases. In contrast, the findings of the SPM and ROI analyses in TLE-no suggested that if relaxation rate decreases are present, they are less uniform and generally milder than in TLE-MTS. This further supports the hypothesis that TLE-no is a distinct clinicopathological entity from TLE-MTS and probably heterogeneous in itself. [source] Postnatal maturation of Na+, K+, 2Cl, cotransporter expression and inhibitory synaptogenesis in the rat hippocampus: an immunocytochemical analysisEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2002Serge Marty Abstract GABA, a major inhibitory neurotransmitter, depolarizes hippocampal pyramidal neurons during the first postnatal week. These depolarizations result from an efflux of Cl, through GABAA -gated anion channels. The outward Cl, gradient that provides the driving force for Cl, efflux might be generated and maintained by the Na+, K+, 2Cl, cotransporter (NKCC) that keeps intracellular Cl, concentration above electrochemical equilibrium. The developmental pattern of expression of the cotransporter in the hippocampus is not known. We studied the postnatal distribution pattern of NKCC in the hippocampus using a monoclonal antibody (T4) against a conserved epitope in the C-terminus of the cotransporter molecule. We also examined the temporal relationships between the developmental pattern of NKCC expression and the formation of perisomatic GABAergic synapses. This study was aimed at determining, with antivesicular inhibitory amino acid transporter (VIAAT) antibodies, whether perisomatic GABAergic synapses are formed preferentially at the time when GABA is depolarizing. During the first postnatal week, NKCC immunolabelling was restricted to cell bodies in the pyramidal cell layer and in the strata oriens and radiatum. In contrast, at postnatal day 21 (P21) and in adult animals little or no labelling occurred in cell bodies; instead, a prominent dendritic labelling appeared in both pyramidal and nonpyramidal neurons. The ultrastructural immunogold study in P21 rat hippocampi corroborated the light-microscopy results. In addition, this study revealed that a portion of the silver-intensified colloidal gold particles were located on neuronal plasmalemma, as expected for a functional cotransporter. The formation of inhibitory synapses on perikarya of the pyramidal cell layer was a late process. The density of VIAAT-immunoreactive puncta in the stratum pyramidale at P21 reached four times the P7 value in CA3, and six times the P7 value in CA1. Electron microscopy revealed that the number of synapses per neuronal perikaryal profile in the stratum pyramidale of the CA3 area at P21 was three times higher than at P7, even if a concomitant 20% increase in the area of these neuronal perikaryal profiles occurred. It is concluded that, in hippocampal pyramidal cells, there is a developmental shift in the NKCC localization from a predominantly somatic to a predominantly dendritic location. The presence of NKCC during the first postnatal week is consistent with the hypothesis that this transporter might be involved in the depolarizing effects of GABA. The depolarizing effects of GABA may not be required for the establishment of the majority of GABAergic synapses in the stratum pyramidale, because their number increases after the first postnatal week, when GABA action becomes hyperpolarizing. [source] Stimulation of keratinocyte differentiation , a new role for the vanilloid receptor subtype 1 (VR1/TRPV1)?EXPERIMENTAL DERMATOLOGY, Issue 2 2005Sonja Ständer Vanilloids and endogenous cannabinoids mediate their actions via the vanilloid receptor subtype 1 (VR1/TRPV1), a non-selective cation channel, which is widely distributed in the central and peripheral nervous system. Only recently, VR1 has been shown to be expressed in keratinocytes in vitro and in vivo. However, a precise description of VR1 localization in epithelial cells was missing. To determine this, we investigated VR1-immunoreactivity as well as mRNA and protein expression in a series of biopsies from normal, diseased, and capsaicin-treated human skin. VR1 was found in epidermal keratinocytes, the inner root sheet and the infundibulum of hair follicles, differentiated sebocytes, sweat gland ducts, and the secretory portion of eccrine sweat glands upon immunohistochemistry, RT-PCR and Western blot analysis. Interestingly, in diseased skin such as prurigo nodularis, psoriasis vulgaris, and atopic dermatitis, VR1 expression in keratinocytes correlated with the degree of epidermal differentiation. Enhanced VR1 immunoreactivity and protein content was found in prurigo nodularis in which epidermal keratinocytes are highly differentiated. Under effective capsaicin therapy of prurigo nodularis, the epidermis thinned and the distribution pattern of VR1 on epidermal keratinocytes normalized. In psoriasis vulgaris, a disease with disturbed epidermal differentiation, less intense immunostaining for VR1 was observed. This could be confirmed by western blot analysis showing less VR1 protein amount in comparison to prurigo nodularis although histologically both showed a thickened epidermis. In atopic dermatitis, which is characterized by a moderate epidermal hyperplasia only and regular differentiated keratinocytes, VR1 immunoreactivity was unchanged in comparison to normal skin. These findings suggest that VR1 may contribute to regular differentiation of keratinocytes. VR1 activation opens non-selective cation channels with high permeability to calcium, a ion that is crucially important for the synthesis of cornification proteins such as involucrin, fillagrin and loricrin. The role of VR1 in other epithelial cells of appendage structures remains to be determined. In summary, VR1 is widely distributed in the skin suggesting a central role for this receptor not only in nociception but also maturation and function of epithelial cells. [source] A new approach to prioritizing marine fish and shellfish populations for conservationFISH AND FISHERIES, Issue 4 2001Einar Eg Nielsen Abstract There has been increasing awareness of the vulnerability of marine organisms to population extirpation and species extinction. While very few documented cases of species extinction exist in the marine environment, it is anticipated that managers will face the dilemma of prioritizing populations of marine fish and shellfish for protection in the near future. Current prioritization procedures have been developed from salmonid models with the intent of applying them to all marine organisms, and in some cases to freshwater and terrestrial taxa. In this review we provide evidence for the relevance of such a process for marine species and further suggest five broad categories of marine organisms that have distinctive traits influencing their genetic structure. The current prioritization models have been adapted to account for each of these species groups. Emphasis is placed on ,Classical Marine Species' which represent the opposite end of the continuum from the salmon model, displaying high within-population genetic variance. From this category, three cod (Gadus morhua) stocks were selected to evaluate a revised scheme developed specifically for ,Classical Marine Species' that includes performance measures such as (i) reduction in number of spawning populations; (ii) reduction of Ne : Nc (ratio of effective to census population size); (iii) changes in life-history traits; (iv) critical density for spawning success; and (v) patchy vs. continuous distribution pattern. When the salmonid scheme was applied, the cod examples were allocated low values, indicating that they were not under threat. However, when the revised scheme was applied, all three cod stocks were allocated high values, indicating that the revised scheme was more reflective of the particular life-history traits of this category of organisms. [source] | |||||||||||||||||||||||||||||||||||||||||||