Establishment and optimization of epithelial cell cultures from human ectocervix,transformation zone,and endocervix optimization of epithelial cell cultures

Cervical cancer is a major public health problem and research using cell culture models has improved understanding of this disease. The human cervix contains three anatomic regions; ectocervix with stratified squamous epithelium, endocervix with secretory epithelium, and transformation zone (TZ) with metaplastic cells. Most cervical cancers originate within the TZ. However, little is known about the biology of TZ cells or why they are highly susceptible to carcinogenesis. The goal of this study was to develop and optimize methods to compare growth and differentiation of cells cultured from ectocervix, TZ or endocervix. We examined the effects of different serum-free media on cell attachment, cell growth and differentiation, and cell population doublings in monolayer culture. We also optimized conditions for organotypic culture of cervical epithelial cells using collagen rafts with human cervical stromal cells. Finally, we present a step-by-step protocol for culturing cells from each region of human cervix.     

River otter and mink occupancy dynamics in riparian systems

Semi-aquatic mammals are dependent upon streams and riparian areas, which are a product of the landscapes they drain. Both local stream morphology and surrounding land use are likely to have important influences on current occupancy of semi-aquatic mammals and potentially affect future geographic distributions. We identified aspects of the riparian system and stream structure at multiple scales that relate to the presence of river otter (Lontra canadensis) and mink (Neovison vison) to better understand how changing landscapes affect occupancy dynamics of these semi-aquatic mammals and to facilitate future monitoring and management. We estimated multi-season occupancy using 103 sites sampled over 6 seasonal sampling periods in southern Illinois, USA (44,526 km²) during 2012–2014. We hypothesized river otter and mink occupancy were related to multiple aspects of landscape and local habitat attributes including land cover, water availability, human disturbance, and stream characteristics. Occupancy of river otter was predicted by large stream size, less developed area near the stream site, and proximity to areas with reintroduced or remnant populations of river otter. Mink were more likely to occupy sites with small streams and decreased water availability near the site. However, top models for both species had low weights and high uncertainty for multiple variables. Habitat-based models may not be the best predictors of occupancy for these carnivores because they are more likely to respond to prey diversity or availability, but landscape changes that decrease natural water availability and increase human disturbance to the stream at the local scale are likely to negatively affect river otter. © 2019 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Synchrony of Seed Dispersal, Hydrology and Local Climate in a Semi-arid River Reach in California

The temporal availability of propagules is a critical factor in sustaining pioneer riparian tree populations along snowmelt-driven rivers because seedling establishment is strongly linked to seasonal hydrology. River regulation in semi-arid regions threatens to decouple seed development and dispersal from the discharge regime to which they evolved. Using the lower Tuolumne River as a model system, we quantified and modeled propagule availability for Populus fremontii (POFR), Salix gooddingii (SAGO), and Salix exigua (SAEX), the tree and shrub species that dominate near-channel riparian stands in the San Joaquin Basin, CA. A degree-day model was fit to field data of seasonal seed density and local temperature from three sites in 2002–2004 to predict the onset of the peak dispersal period. To evaluate historical synchrony of seed dispersal and seasonal river hydrology, we compared peak spring runoff timing to modeled peak seed release periods for the last 75 years. The peak seed release period began on May 15 for POFR (range April 23–June 10), May 30 for SAGO (range May 19–June 11) and May 31 for SAEX (range May 8–June 30). Degree-day models for the onset of seed release reduced prediction error by 40–67% over day-of-year means; the models predicted best the interannual, versus site-to-site, variation in timing. The historical analysis suggests that POFR seed release coincided with peak runoff in almost all years, whereas SAGO and SAEX dispersal occurred during the spring flood recession. The degree-day modeling approach reduce uncertainty in dispersal timing and shows potential for guiding flow releases on regulated rivers to increase riparian tree recruitment at the lowest water cost.     

利用GIS模拟变量施肥尺度对施肥量的影响研究

以玉米氮肥变量施肥为例。采用GIS技术分别模拟不同肥力水平、不同空间变异和不同相关距条件下变量施肥尺度对施肥量的影响．首先用“Turning Band Method”方法随机生成符合指定均值、方差和空间分布(半方差模型)的一组表示最小施肥单元的土壤养分数据,每组10~4个数据,对每组数据进行了100个等级尺度单元的相关施肥量计算和分析．模拟结果表明：(1)随着变量施肥单元面积减小,施肥量不是减少,而是增加或保持不变;(2)相同土壤肥力,空间变异越大时,随着施肥尺度增大,平均施肥量增大越明显,而且施肥临界养分过渡带的变量施肥合理性受尺度影响最大．     

Testing the higher-taxon approach: a case study of aquatic marcophytes in China’s northwest arid zone and its implications for conservation

Assessments of biodiversity are time-consuming and require a high level of expert knowledge. A reduced set of taxonomic ranks other than species has been proved to be useful for rapid and cost-effective assessment of biodiversity. However, few studies have examined how well this method performs for aquatic plant group that of enormous ecological importance. We studied the aquatic plant flora in the arid zone of China and examined whether the distribution of species α- and β-diversity could be predicted well from genus-, and family-levels. Analyses of 3 years field data showed that significant and positive relations exist between α-diversity of species and α-diversity of genera and family in both entire arid zone and five sub-zones. In contrast, β-diversity at species level is difficult to predict from β-diversity indexes at higher taxonomic level. The results indicate that higher-taxon α-diversity, especially at the generic level in our research, can be useful surrogates of species α-diversity for aquatic plants conservation.     

Keystone Interactions: Salmon and Bear in Riparian Forests of Alaska

The term “keystone species” is used to describe organisms that exert a disproportionately important influence on the ecosystems in which they live. Analogous concepts such as “keystone mutualism” and “mobile links” illustrate how, in many cases, the interactions of two or more species produce an effect greater than that of any one species individually. Because of their role in transporting nutrients from the ocean to river and riparian ecosystems, Pacific salmon (Oncorhynchus spp.) and brown bear (Ursus arctos) have been described as keystone species and mobile links, although few data are available to quantify the importance of this interaction relative to other nutrient vectors. Application of a mass balance model to data from a southwestern Alaskan stream suggests that nitrogen (N) influx to the riparian forest is significantly increased in the presence of both salmon and bear, but not by either species individually. The interactions of salmon and bear may provide up to 24% of riparian N budgets, but this percentage varies in time and space according to variations in salmon escapement, channel morphology and watershed vegetation characteristics, suggesting interdependence and functional redundancy among N sources. These findings illustrate the complexity of interspecific interactions, the importance of linkages across ecosystem boundaries and the necessity of examining the processes and interactions that shape ecological communities, rather than their specific component parts.     

The Spatial Structure of Variability in a Semi-arid, Fluvial Ecosystem

The arrangement and composition of flowpath types within a given network are thought to govern its functioning. This concept assumes that different flowpath types are functionally distinct. We investigated this assumption in a fluvial ecosystem by comparing the riparian zone, parafluvial zone (in-channel gravel bars), and surface stream. We hypothesized that differences in advection, uptake, and sorption would render material cycles more (a) open and (b) mutable in the surface stream, whereas the converse would occur in the riparian zone, and an intermediate state would be seen in the intervening parafluvial zone. To test our first hypothesis, we predicted that spatial heterogeneity in solute concentrations would be least in the surface stream, greater in the parafluvial zone, and greatest in the riparian zone. Using a null model, we ascertained that this pattern was shown by all solute species we examined (nitrate, ammonium, total dissolved inorganic nitrogen [DIN], dissolved organic N, total dissolved N, soluble reactive phosphorus, dissolved organic carbon, and chloride). To test our second hypothesis, we predicted that temporal change in spatial heterogeneity would be greatest in the surface stream, less in the parafluvial zone, and least in the riparian zone. Nitrate, DIN, and chloride showed this pattern. In particular, surface stream inorganic N was less spatially variable following months of high rainfall. According to an extant hypothesis, these results suggest that inorganic N processing may be a stable function in this ecosystem. Other solute species did not support our second prediction, perhaps because their retention and release dynamics are influenced principally by geochemistry. Generally, our findings indicate that a geomorphic template can generate spatial patterns in ecosystem function, warranting an expansion of the spiraling framework to a variety of flowpath types.     

Disappearance of deep profundal zoobenthos in Lake Ikeda, southern Kyushu, Japan, with relation to recent environmental changes in the lake

A benthological survey in a deep caldera, Lake Ikeda, southern Kyushu, Japan, in 1998 revealed that no zoobenthos were found in the deep profundal, although two tubificid oligochaetes, Tubifex tubifex and Limnodrilus hoffmeisteri, and a chironomid, Procladius sp., were distributed in the upper profundal zone. This is the first record of oligochaete composition in the lake. Lake Ikeda had been typically oligotrophic until the 1940s, and zoobenthic assemblages were recorded throughout the profundal bottom in the 1920s and 1970s. Recent disappearance of the deep profundal zoobenthos could be caused by the stagnation of anoxic waters in the hypolimnion, in connection with eutrophication triggered by nutrient loading, as well as change in the thermal circulation system presumably caused by global warming.     

A gradient analysis based on the buffer zones of urban landscape pattern of the constructed area in Guigang City, Guangxi, China

Over the last century urbanization on the landscape has increased and intensified. Urban development has a great impact on the environment at the local, regional and even global levels. As a driving force in global change, the need to understand the dynamics of urban pattern and its change in an accurate and efficient manner is ever more pressing. Based on aerial color infrared photography in 1985 and QuickBird satellite imagery in 2004 and according to the standard for plan and construction of city land use, the landscape of Guigang City was divided into 11 types. In the landscape classification maps, 31 buffer zones, each being 200 m wide, were divided. With the aid of GIS software ArcView 3.2 and landscape pattern analysis software FRAGSTATS 3.3, the landscape spatial patterns of each buffer zone were analyzed at the landscape level and class level. The landscape indices, such as patch size, patch fractal dimension, diversity index and evenness index, were calculated. The results indicated the following: The total area of the residential land and the communal land in 2004 covered 46.3% of the entire constructed area of Guigang City and the sum of the patch number of the two patch types occupied about 39.7% of the total patch number, while the percentages were respectively 48.2% and 45.4% in 1985. This showed that the mosaic landscape with the residential land and communal facilities land became increasingly unclear following urban development and landscape diversity. Based on the gradient analysis with the landscape-level index and the class-level index, there were two business and finance centers in the constructed area. One was located in the urban center with a range of 0.8 km; the other was from the 10^th to the 16^th zone. In each buffer zone, the mean patch size was larger and the landscape shape was more regular in 2004 than in 1985. Furthermore, the Shannon diversity index of each buffer zone rose in 2004 with patch richness and evenness increasing. The landscape index computed for the main landscape types (communal facilities land, industrial estate land, residential land and farmland) in the middle of the buffer zones clearly indicated the changes taking place in urbanization. The patch size and the patch number of industrial estate land and farmland also pointed to these changes, while communal facilities land and residential land assumed another similar tendency towards changes. In each gradient zone, industrial estate land had the most complex shape, the lowest area percentage of each zone and the biggest mean patch size, whereas communal facilities land and residential land were opposite to industrial estate land. Farmland had a steady percentage along the buffer zone and its continuous distribution had an important impact on the urban eco-environment. The question of how to relate the pattern of changing characteristics along the buffer zone to the urban ecological process and urban ecological planning remains to be studied further in the future.     

明永冰川垂直气候带中可培养低温细菌多样性分析

本研究对位于云南滇西北的明永冰川地区暖温带、中温带和寒温带三个不同垂直气候带中可培养低温细菌的多样性进行了研究。利用四种不同培养基对该地区可培养低温细菌进行了分离纯化,共得到细菌37 513株,根据菌落形态特征分为了391种,其中LB培养基分离到99种,Organic培养基分离到78种,PSG培养基分离到96种,PYGV培养基分离得到118种,可以看出寡营养培养基PYGV分离得到的细菌种类多于LB和Organnic等富营养培养基,表明PYGV针对冰川地区细菌的分离与鉴定更为合适;通过革兰氏染色和扫描电镜观察表明大部分菌株为革兰阴性杆菌;对已分离得到的优势菌进行了16S rRNA基因测序并构建系统发育树,分析得出:假单胞菌属(Pseudomonas)、耶尔森氏菌属(Yersinia)和黄杆菌属(Flavobacterium)在明永冰川不同垂直气候带上均有分布,其中假单胞菌属最多占据35%;而寡养单胞菌属(Stenotrophomonas)是寒温带上特有的菌属。本研究证明明永冰川地区垂直气候带中可培养低温细菌多样性非常丰富,也为下一步了解这一特殊地理生态环境下微生物的群落演替规律、研究冰川环境中微生物群落如何响应气候变化提供了参考。