Patterns Of Spatial Organization Research Articles

Opposite alterations of DNA methyltransferase gene expression in endometrioid and serous endometrial cancers

Objective To examine the DNA methyltransferase (DNMT) mRNA and protein levels in endometrioid and serous cancers and to study the relationship between DNA methyltransferase expression and endometrial cancer development. Methods Normal endometrium, Grade I and Grade III endometrioid carcinoma tissues and cell lines, as well as serous cancer tissues, were analyzed for DNMT expression. Real-time PCR and Western blot techniques were employed to measure the mRNA and protein levels of the four DNA methyltransferases, DNMT1, DNMT2, DNMT3A, and DNMT3B. Immunohistochemistry was performed to detect alterations in DNMT nuclear localization and spatial organization patterns. Results While DNMT2 and DNMT3A expression appear to be normal, two- to fourfold increase in DNMT1 and DNMT3B were found in both Grade I and Grade III endometrioid cancers. In addition, the poorly differentiated cell lines expressed relatively higher DNMT levels than well-differentiated cells. In contrast to endometrioid carcinomas, serous cancers expressed substantially lower levels of DNMT1 and DNMT3B than normal controls, with four- and twofold reduction observed in DNMT1 and DNMT3B mRNA levels, respectively. Western blot analysis confirmed opposite expression patterns of DNMT1 and DNMT3B protein in endometrioid and serous cancers. Immunohistochemistry showed normal nuclear localization of DNMT1 and DNMT3B in Type I and Type II cancer specimens as well as cell cultures. Conclusion Two opposite DNMT expression patterns were identified in endometrioid and serous cancers. The concerted upregulation in maintenance and de novo DNA methyltransferases in endometrioid carcinomas is consistent with a tendency for gene-specific hypermethylation observed in this histologic subtype, and may be implicated in tumor suppressor silencing. In contrast, the downregulation of maintenance and de novo DNA methyltransferases in serous cancers suggests that these tumors may contain hypomethylated genomic DNA, which has been associated with a higher mutation rate and is consistent with the known pathogenesis of serous-specific phenotypes. Taken together, the data suggest that divergent DNA methylation pathways may be implicated in the development of Type I and Type II endometrial cancers.

ラッタナコシン地区(バンコク)のショップハウスの空間構成とその変容に関する考察 : 土地所有形態の異なる3地区のショップハウスの比較

Shophouses of Ratanakosin, as its name suggests, are bi-functional buildings, one of them is commercial and the other is living. Variations of shophouse spatial organization are found in composition of their elements such as open court, stair, toilet and backlane. However, at the first stage of construction, shophouses of the same group generally had same patterns of spatial organization but later underwent changes depending on usage patterns. Finally, their spatial organization transformed into various types regardless of their origin and spatail articulation. Purpose of this paper is to clarify the characteristics of the spatial organization of shophouses. Three blocks of shophouse from three main landholdings, namely temple; Bureau of the Crown Property; and, the private sector have been selected as objects of study. A comparative study is carried out to determine the similarities and differences in their transformation process. Finally, the relationship between Building Code and transformation in shophouse will be discussed.

Arquitectura como tecnología de construcción de la realidad social

Se desarrolla textualmente el enfoque arqueotectónico reflejado en el póster homónimo presentado en el I Seminario Internacional de Arqueología de la Arquitectura con el que se pretendía mostrar gráficamente la potencialidad y aplicabilidad al registro arqueológico de determinadas analíticas y metodologías desarrolladas en el ámbito interdisciplinar de la Arqueología de la Arquitectura. Partiendo de una propuesta teórica concreta definida a partir de la Arqueología del Paisaje postprocesual, abordamos el análisis sintáctico del espacio doméstico a nivel de poblado como herramienta básica para alcanzar una definición de modelos o patrones de organización espacial que fundamenten una interpretación sociológica de las formaciones socioculturales del pasado.
 
 En este sentido mostramos un ejemplo práctico concreto: la aplicación de analíticas espaciales a un poblado fortificado galaicorromano prácticamente excavado en extensión permitirá esbozar el modelo de espacialidad vigente en ese período ahondando en la problemática de la estabilidad y pervivencia de tradiciones arquitectónicas de la Edad del Hierro conjuntamente con el factor de cambio y ruptura impuestos por la romanización del NW peninsular.

Progesterone involvement in breast development and tumorigenesis—as revealed by progesterone receptor “knockout” and “knockin” mouse models

In light of recent clinical trials, the debate concerning the risks and benefits of progestin-based postmenopausal hormone replacement therapy (HRT) has reached a renewed level of urgency. Irrespective of the position taken, the consensus is that more basic research needs to be performed to address progesterone’s fundamental role in mammary development and tumorigenesis. Towards this end, the progesterone receptor knockout (PRKO) mouse demonstrated that progesterone is essential for pregnancy-associated mammary gland ductal side-branching and alveologenesis and that these morphological changes are dependent on progesterone-induced mammary epithelial proliferation. Importantly, the PRKO mouse showed that the progesterone-proliferative signal significantly contributes to mammary tumor susceptibility in an established mammary tumor model. Insight into the cellular mechanism(s) by which progesterone affects mammary morphogenesis has been disclosed by a new PR-LacZ knockin mouse, which revealed that PR’s spatial expression pattern undergoes precise choreographed distributional changes that precede key stages in postnatal mammary development. In the case of early pregnancy, the segregation of cells undergoing progesterone-induced proliferation from those that express PR implicates a paracrine mode of action for progesterone-induced mammary epithelial proliferation, whereas the preparturient decline of PR expression underscores the need to remove this signal for full functional differentiation of this tissue. Our findings support the proposal that the mammary gland’s normal response to the progesterone-signal is dependent upon specific spatial organizational patterns of PR expression and that derailment in these cellular processes may contribute to abnormal mammary development, including cancer. This review concludes by emphasizing the need to identify the downstream molecular targets that mediate progesterone’s effects in this tissue. Identification of such targets will not only enhance our mechanistic understanding of progesterone’s role in mammary development and cancer, but may also facilitate the formulation of new design strategies in breast cancer diagnosis and/or treatment.

A value chain approach to financial centres – The case of Frankfurt

This paper uses a value chain approach to identify possible patterns of spatial (re)organisation resulting from the implementation of information and communication technologies (ICT) in wholesale financial services. Although ICT can be used to split up production processes and thus increase mobility, proximity – not only spatial but also cultural, organisational and professional – remains essential for the financial industry. Thus, while ICT may induce a ‘re–bundling’ of functions among financial centres, location continues to be a relevant factor. An analysis of the value chains of three financial products is presented with a focus on implications for the financial centre in Frankfurt. Frankfurt is a particularly interesting case study of this phenomenon as it is one of the centres for the development of ‘financial technology’, such as computer–based trading systems with remote access.

STATIS-CoA: A methodological solution to assess the spatio-temporal organization of species assemblages. Application to the demersal assemblages of the French Mediterranean Sea

The organizational patterns of demersal assemblages (fish, crustaceans and cephalopods) in the Gulf of Lions were investigated on the basis of a set of six bottom trawl surveys performed between 1994 and 1999 (MEDITS programme). The use of a recent multitable method (STATIS-CoA) provided a detailed representation of the stable and variable parts of the spatial organization of demersal assemblages during the studied period. We showed that demersal assemblages of the Gulf of Lions were organized along a coast-open sea gradient. At the scale of the Gulf, we showed that this gradient can be split into three areas: 1) the coastal region and the continental shelf (10 to 200 m depth), 2) the upper slope (200 to 500 m) and 3) the deeper slope (500 to 800 m). Associated to this bathymetric structuring we found a species-richness gradient which decreases from the coast to the upper slope. Our analysis showed that this spatial organization pattern was highly persistent during the course of the study. However, some species caught in the slope area exhibited a strong variability of their spatial distribution mainly during the 1999 survey. From a methodological point of view, STATIS-CoA offers a rigorous theoretical framework for the simultaneous analysis of a three-dimensional set of data. Applied in the field of fisheries ecology, this method (1) constitutes a relevant way to analyse the spatial organization of species assemblages and its pattern of changes, and (2) could be of particular interest to treat the MEDITS data both at a local and at the North Mediterranean Sea scales.

Control of chromosome replication in caulobacter crescentus.

Caulobacter crescentus permits detailed analysis of chromosome replication control during a developmental cell cycle. Its chromosome replication origin (Cori) may be prototypical of the large and diverse class of alpha-proteobacteria. Cori has features that both affiliate and distinguish it from the Escherichia coli chromosome replication origin. For example, requirements for DnaA protein and RNA transcription affiliate both origins. However, Cori is distinguished by several features, and especially by five binding sites for the CtrA response regulator protein. To selectively repress and limit chromosome replication, CtrA receives both protein degradation and protein phosphorylation signals. The signal mediators, proteases, response regulators, and kinases, as well as Cori DNA and the replisome, all show distinct patterns of temporal and spatial organization during cell cycle progression. Future studies should integrate our knowledge of biochemical activities at Cori with our emerging understanding of cytological dynamics in C. crescentus and other bacteria.

Principles of linear and angular vestibuloocular reflex organization in the frog.

We compared the spatial organization patterns of linear and angular vestibuloocular reflexes in frogs by recording the multiunit spike activity from cranial nerve branches innervating the lateral rectus, the inferior rectus, or the inferior obliquus eye muscles. Responses were evoked by linear horizontal and/or vertical accelerations on a sled or by angular accelerations about an earth-vertical axis on a turntable. Before each sinusoidal oscillation test in darkness, the static head position was systematically altered to determine those directions of horizontal linear acceleration and those planes of angular head oscillation that were associated with minimal response amplitudes. Inhibitory response components during angular accelerations were clearly present, whereas inhibitory response components during linear accelerations were absent. Likewise was no contribution from the vertical otolith organs (i.e., lagena and saccule) observed during vertical linear acceleration. Horizontal linear acceleration evoked responses that originated from eye muscle-specific sectors on the contralateral utricular macula. The sectors of the inferior obliquus and lateral rectus muscles on the utricle had an opening angle of 45 and 60 degrees, respectively and overlapped to a large extent in the laterorostral part of the utricle. Both sectors were coplanar with the horizontal semicircular canals. The sector of the inferior rectus muscle was narrow (opening 5 degrees), laterocaudally oriented, and slightly pitched up by 6 degrees. Angular acceleration evoked maximal responses in the inferior obliquus muscle nerve that originated from the ipsilateral horizontal and the contralateral anterior vertical canals in a ratio of 50:50. Lateral rectus excitation originated from the contralateral horizontal and anterior vertical semicircular canals in a ratio of 80:20. The excitatory responses of the inferior rectus muscle nerve originated exclusively from the contralateral posterior vertical canal. Measured data and known semicircular canal plane vectors were used to calculate the spatial orientation of maximum sensitivity vectors for the investigated eye muscle nerves in semicircular canal coordinates. Comparison of the directions of maximal sensitivity vectors of responses evoked by linear or angular accelerations in a given eye muscle nerve showed that the two vector directions were oriented about orthogonally with respect to each other. With this arrangement the linear and the angular vestibuloocular reflex can support each other dynamically whenever they are co-activated without a change in the spatial response characteristics. The mutual adaptation of angular and linear vestibuloocular reflexes as well as the differences in their organization described here for frogs may represent a basic feature common for vertebrates in general.

Spatial Organization of Bobcats (Lynx rufus) in Southern Illinois

Abstract Many aspects of spatial organization in solitary carnivores remain unknown due to prohibitively low sample sizes and reliance on only annual home range and overlap data. We estimated size, overlap and fidelity of annual and seasonal home ranges and core areas of 52 (22 male, 30 female) adult bobcats (Lynx rufus) in southern Illinois during 1995–1999 and quantified temporal spacing. We report an unusual pattern of spatial organization for bobcats such that, although male and female annual home-range sizes were similar to other regional populations, we found relatively high levels of intrasexual home-range overlap for males and females. Although intrasexual home-range overlap was extensive, core areas were nearly exclusive, implying that core areas confer benefits to bobcats by reducing competition for resources and may represent areas of more aggressive territoriality within the home range. Only 4 of 52 (8%) bobcats shifted annual home ranges, indicating stable spatial organization in the absence ...

Floristic composition across a climatic gradient in a neotropical lowland forest

Abstract. This study deals with the floristic composition of lowland tropical forest in the watershed of the Panama Canal. The floristic composition of large trees in 54 forest plots was analysed with respect to environmental factors, including precipitation, geologic parent material, stand age, topography, and soils. The plots contain 824 species of trees with a diameter at breast height ≥10 cm and represent a regional flora with exceptional β‐diversity. Plot data indicate that the Panamanian forest is strongly spatially structured at the landscape scale with floristic similarity decreasing rapidly as a function of inter‐plot geographic distance, especially for distances <5 km. The ordinations and patterns of endemism across the study area indicate broad floristic associations well correlated with Holdridge life zones. The results indicate the positive aspects of life zone classification at regional scales, while simultaneously highlighting its inadequacy for finer scales of analysis and resource management. Multivariate gradient analysis techniques (Non‐metric Multidimensional Distance Scaling and Detrended Correspondence Analysis) show clear patterns of floristic variability correlated with regional precipitation trends, surficial geology, and local soil attributes. Geologic and edaphic conditions, such as acidic soils or excessively drained limestone substrates, appear to override the effects of precipitation and modify forest composition. We conclude that the Panamanian forest shows clear patterns of spatial organization along environmental gradients, predominantly precipitation. The rapid decline in floristic similarity with distance between stands also suggests a role for dispersal limitation and stochastic events.

Vascular biology of endothelin signal transduction.

1. Endothelins regulate cell function by interacting with two classes of cell surface receptors, ETA and ETB receptors. Both receptor types are members of the heptahelical transmembrane-spanning receptor superfamily and couple via G-proteins to multiple intracellular effectors. 2. Many of the cellular responses induced by endothelins are mediated by changes in cytoplasmic Ca2+ concentration. Stimulation of inositol 1,4,5-trisphosphate (IP3) formation promotes release of Ca2+ from intracellular stores via IP3-sensitive Ca2+ channels. This mechanism accounts for the initial transient peak of the Ca2+ elevation. The entry of Ca2+ across the plasma membrane through multiple types of Ca2+ channels is responsible for the sustained phase of Ca2+ elevation and, together, both mechanisms regulate cell function. 3. Endothelin-mediated Ca2+ signals vary markedly in duration, spatial organization and temporal pattern. The elevations in Ca2+ are sustained, transient or oscillatory and occur either globally or are localized to discrete spatial domains. These different Ca2+ signals, which are dependent on the availability of specific ion channels, control distinct cellular functions. Ryanodine-sensitive Ca2+ release channels may be important in determining the organization of the Ca2+ signal. 4. Endothelin-induced Ca2+ elevations near the plasma membrane stimulate the opening of Ca(2+)-dependent K+ and Cl- channels. These channels are key regulators of membrane potential and, consequently, regulate the activity of voltage-dependent Ca2+ influx pathways. 5. Endothelin regulates the growth and differentiation of cells. It markedly potentiates the mitogenic response of other growth factors, an effect that involves activation of the mitogen-activated protein kinase cascade and induction of early response genes. 6. Finally, the vascular actions of endothelin are influenced by the relative expression of specific ion channels, the spatial and temporal pattern of the Ca2+ signal and the cellular composition of the vascular wall.

A comparison of the geometry, spatial organization and fracture patterns associated with forced folds and buckle folds

Abstract In this paper the three-dimensional geometry and spatial organization of folds (both buckle folds and various types of forced folds) are considered, together with their associated fracture patterns, in an attempt to determine if these features can be used in regions of poor exposure or in areas where the geologist must rely on seismic data to indicate the type of folding that has occurred. This study of the relationship between the various fold types and associated fracture patterns draws on theoretical considerations of ideal conceptual models of folds, analogue models and field studies.

Dynamics of Age-Structured Predator-Prey Populations in Space: Asymmetrical Effects of Mobility in Juvenile and Adult Predators

In many natural predator-prey systems, there are differences in mobility between individual predators and prey. In this paper, we use individual-based models to examine how differences in mobility of age-structured predator populations affect the spatial and temporal dynamics of predator-prey populations. Predators and prey in our model do not possess any behavioral rules for aggregation, and spatial heterogeneity is internally generated from the interaction among individuals (i.e. populations are not externally subdivided into patches). We show that differential mobility by juvenile and adult predators can have an asymmetrical effect on stability when prey mobility is relatively limited. Increasing the mobility of adult predators destabilizes predator-prey dynamics, while changing juvenile mobility does not. We also investigate stage-structured dispersal by predators and show that, contrary to general conclusions from metapopulation theory, widespread dispersal of predator offspring can actually stabilize dynamics and lead to novel patterns of spatial organization of predator and prey populations. With limited mobility of individuals and local offspring production, stability arises because of the asynchrony of dynamics among many different regions of the lattice. Dispersing predator offspring (i.e. decoupling local recruitment from local predator-prey interactions) produces stability of local regions and large-scale spatial patterning.

Spatial distribution in the bushy-tailed wood rat (Neotoma cinerea) and its implications for the mating system

We examined the spatial distribution of reproductively active bushy-tailed wood rats (Neotoma cinerea) over three breeding seasons (1992–1994), using radiotelemetry. An index value was calculated for each animal to describe the degree of intersexual and intrasexual overlap. We tested the prediction that our pattern of spatial distribution would resemble that of a polygynous mating system, which has been suggested for this species. Over the three seasons of study, no significant differences were observed between the degrees of intersexual and intrasexual overlap of males. Females exhibited either similar degrees of intersexual and intrasexual overlap (1992 and 1993) or a greater degree of intersexual than intrasexual overlap (1994). Such a pattern of spatial overlap does not support the predictions of a polygynous mating system. We suggest that bushy-tailed wood rats display a pattern of spatial organization that is consistent with a promiscuous mating system.

Spatio-Temporal Patterns of Home Range Use by Foxes (Vulpes vulpes) in Urban Environments

Territories, being specific defended areas, are often considered as spatially consistent throughout the life span of an individual (e.g. Brown & Orians 1970). However, in some circumstances territory size and configuration may be adjusted to incorporate changes in occupancy of neighbouring territories or changes in the distribution and abundance of certain limiting resources (Kruuk & Macdonald 1985). Doncaster & Macdonald (1991) reported that territories of foxes, Vulpes vulpes, in the city of Oxford showed a specific type of instability, 'drifting' in synchrony across the city so that a 'honeycomb pattern of congruent ranges' was maintained. 'Drifting territoriality' is therefore not simply random instability of home ranges, but is a directional phenomenon, and can be pictured as a fixed spatial arrangement of territories moving across a landscape in a non-cyclical manner. Doncaster & Macdonald (1991) measured the rate of this movement as equivalent to the size of one home range each year. Such 'drifting territoriality' had not been previously recorded for any species, and those authors hypothesized that it was a behavioural response by foxes to the instability of urban environments in terms of their high mortality and rapid changes in the pattern of food resources. In this paper, we test this hypothesis using data from foxes living in another British city. We investigate (i) the pattern of spatial organization exhibited by foxes living in Bristol, (ii) whether the foxes living in Bristol showed any evidence of territory instability, in particular whether they showed any evidence of drifting territoriality as reported for the foxes living in Oxford, and (iii) whether differences in the patterns of resource availability and fox mortality in Bristol are indicative of stability or instability in the urban environment.

Shrub architecture and occupation of space in a Mediterranean sclerophyllous shrubland

Abstract. Shrubland communities in Central Spain were studied through classifying growth forms of woody species and determining the shared use of the ground in progressively smaller spaces. 516 plants belonging to the six most abundant species and taken from different sites were included in biometric measurements. Principal Component Analysis (PCA) was used to detect the trends of variation in the architecture of plants. The individuals were classified on the basis of the results of the PCA and different morphological types were detected, mainly ‘elliptical’, ‘spherical’or ‘variable’according to their shape. These morphological types were adopted by most plants depending on their location and community.The horizontal occupation of space seems to be determined by whether or not the species rooted close to each other are able to occupy different strata. The co‐occurrence of two species in a reduced space is not facilitated when the two species have the same architecture. Then a spatial segregation tends to occur at a fine scale. The results can be interpreted as an optimization strategy of the shrubland ‘biomass/horizontal occupied area ratio’, which can be maximized in different environmental situations. It can also help to explain the ‘grain’ size of the pattern of horizontal spatial organization of the shrubland.

Comparison of Niche-Packing and Community Organization in Desert Rodents in Asia and North-America

We compared patterns of species diversity, locomotory morphology, feeding modes, and spatial organisation for rodent communities in four Asian deserts (Kyzylkum, Gobi, ?Thar, Negev) and one North American (Chihuahuan) desert. Deserts were similar in gamma and alpha diversity. A positive relationship between regional species diversity (and biomass) and mean annual precipitation was found. The Asian deserts showed a greater degree of divergence and specialisation between bipedal and quadrupedal forms. The range of feeding modes was similar in deserts on both continents, but the Negev was the only Asian desert in which granivory was as important as in the Chihuahuan. Temperate Asian desert rodents were organised into spatial guilds, separated primarily by characteristics of the soil and perennial vegetation. North American desert rodent species overlapped more extensively in habitat use. The similarities and differences between these deserts can be explained by their biogeographic histories.

Use of time and space by platypus (Ornithorhynchus anatinus: Monotremata) along a Victorian stream

Radio‐tracking and mark recapture methods were used to characterize the spatial organization and temporal activity patterns of free‐ranging platypuses in southern Victoria. The study area supported an estimated 1.3‐2.1 adult or subadult animals per kilometre of stream in the three summers sampled. The individual home ranges of 15 radio‐tagged animals comprised 0.33‐2.28 km of stream; animals foraging exclusively in the stream had significantly longer ranges (mean=1.40 km) than animals which also foraged in associated pond habitats (mean=0.64km). Home ranges of grown females overlapped with those of neighbouring grown females, subadult and adult males, and juveniles (<l y old) of both sexes. While the home ranges of a subadult and adult male, and subadult and juvenile male also overlapped substantially, only one sexually mature male was trapped at any given point in time, suggesting that adult males may occupy mutually exclusive home ranges in the study area. Most platypuses were observed to den at more than one location: burrow sharing was recorded in the case of a subadult and adult male, two grown females, a grown female and independent first‐year female, and two independent first‐year females. The mean length of time that nine individuals spent in dens per resting period varied from 11.6‐16.7 h. In addition, two grown females remained inactive in dens for longer periods (3‐6.5 days) in late May‐June.

Communication technologies and spatial organization of multi-unit firms in metropolitan areas

Departing from traditional location theory (which treats a firm as a single-unit entity), in this paper we consider that each firm consists of multiple units that exchange information or services. Specifically, we develop a general equilibrium model of the city,in which each firm consists of a front-unit (e.g. business office) and back-unit (e.g. plant or back-office). Each front-unit interacts with all other front-units for the purpose of business communications, while each back-unit exchanges information or management services only with the front-unit of the same firm. Each firm must choose the location of its front-unit and back-unit optimally. The equilibrium spatial configuration of the city is determined as an outcome of interactions among all firms and households through competitive land and labor markets. We show that, depending on parameters, a variety of interesting patterns of metropolitan spatial organization emerges.

Structure and spatial organization of an Amazonian terra firme forest primate community

ABSTRACTA high-diversity primate community consisting of 13 species was examined at an entirely undisturbed and remote terra firme forest near the headwaters of the Urucu River, Amazonas, Brazil. Twelve of these species used a 900-ha study plot, located 4 km or more inland from the river, and comprised a total group density of 16 groups km−2, an overall density of 146 individuals km−2, a crude community biomass of 381 kg km−2, and a metabolic biomass of 278 kg0.75km−2. These species were occasionally found together within small (≥1 km2) areas of forest, so long as they included the full complement of available forest types. More frequently, however, only half the species co-occurred in a single habitat type at any one time, reflecting a relatively consistent pattern of subcommunity spatial organization. Habitat generalist species making extensive, yearround use of the predominant habitat type (high forest), were common, whereas habitat specialists were uncommon to very rare, and confined to minor habitats. Those species coexisting throughout the year in high forest were found to segregate vertically from one another. These and other modal patterns of community structure were disrupted seasonally by long-distance, inland movements by two ‘igapó’ forest species living in large groups – squirrel monkeys and white-face capuchins – to high forest areas, which apparently resulted from a food bottleneck in their habitat. Another species found in large groups – woolly monkeys – also exercised seasonally vagrant movements within the high forest matrix, which coincided with periods of greatest scarcity of mature fleshy fruits.