circPVT1通过miR-24-3p/let-7a-5p/FSCN1轴促进鼻咽癌细胞侵袭迁移

目的 鼻咽癌是一种来源于鼻咽上皮的恶性肿瘤,其临床特征之一是易发生淋巴转移,但是目前鼻咽癌转移的分子机制尚未阐明。circPVT1是由PVT1基因2号外显子反向拼接形成的环状RNA (circRNA),在多种肿瘤中表达上调,本文探讨了circPVT1在鼻咽癌侵袭迁移中的作用和分子机制。方法 通过RT-qPCR检测circPVT1及其下游miRNA和FSCN1在鼻咽癌细胞的表达情况,Transwell和划痕愈合实验检测circPVT1对鼻咽癌细胞侵袭迁移的影响,RNA pull-down实验检测circPVT1结合的miRNA,双荧光素酶报告实验检测miR-24-3p和let-7a-5p靶向抑制FSCN1 mRNA表达。结果 在鼻咽癌细胞中过表达circPVT1可以促进鼻咽癌细胞侵袭迁移,而敲低circPVT1则可以抑制鼻咽癌细胞的侵袭迁移。进一步研究发现,circPVT1可以通过竞争性吸附miR-24-3p和let-7a-5p,上调FSCN1的表达,从而促进鼻咽癌细胞的侵袭迁移。结论 circPVT1通过miR-24-3p/let-7a-5p/FSCN1轴促进鼻咽癌细胞侵袭迁移,证实c...     

Low genetic diversity and population connectivity fuel vulnerability to climate change for the Tertiary relict pine Pinus bungeana

Endemic species are important components of regional biodiversity and hold the key to understanding local adaptation and evolutionary processes that shape species distributions. This study investigated the biogeographic history of a relict conifer Pinus bungeana Zucc. ex Endl. confined to central China. We examined genetic diversity in P. bungeana using genotyping-by-sequencing and chloroplast and mitochondrial DNA markers. We performed spatial and temporal inference of recent genetic and demographic changes, and dissected the impacts of geography and environmental gradients on population differentiation. We then projected P. bungeana's risk of decline under future climates. We found extremely low nucleotide diversity (average π 0.0014), and strong population structure (global F_ST 0.234) even at regional scales, reflecting long-term isolation in small populations. The species experienced severe bottlenecks in the early Pliocene and continued to decline in the Pleistocene in the western distribution, whereas the east expanded recently. Local adaptation played a small (8%) but significant role in population diversity. Low genetic diversity in fragmented populations makes the species highly vulnerable to climate change, particularly in marginal and relict populations. We suggest that conservation efforts should focus on enhancing gene pool and population growth through assisted migration within each genetic cluster to reduce the risk of further genetic drift and extinction.     

Temporal Variation in the Relative Abundance of Fruit Bats (Megachiroptera: Pteropodidae) in Relation to the Availability of Food in a Lowland Malaysian Rain Forest

The aims of this study were to investigate the diet and relative abundance of fruit bats in a lowland Malaysian rain forest and to test the hypothesis that the local assemblage structure of fruit bats varies significantly over time in relation to the availability of food. In total, 352 fruit bats of eight species were captured during 72,306 m² mist‐net hours of sampling between February 1996 and September 1999. Three species of fruit bats (Balionycteris maculita, Chironax melanocephalus, and Cynopterus brachyotis) that fed on a wide range of “steady state” and “big bang” food resources were captured continuously throughout the study period, with no significant variation in capture rates over time. In contrast, five species that fed exclusively or almost exclusively on “big bang” food resources were sampled intermittently, with significant temporal variation in the capture rates of two species (Cynopterus horsfieldi and Megaerops ecaudatus). Significant variation in the capture rates of the remaining three species (Dyacopterus spadiceus, Eonycteris spelaea, and Rousettus amplexicaudatus) could not be detected due to small sample sizes. Since ephemeral “big bang” food resources were only sporadically available within the study area and were associated with large canopy trees and strangler figs, these results suggest that food abundance, or the availability of specific food items, may be important factors limiting local fruit bat species diversity in old‐growth Paleotropical rain forest. Thus, only three fruit bat species were locally resident within the forest throughout the study period. Therefore, further studies on the ranging behavior and habitat requirements of Malaysian fruit bats are required to assess the adequacy of existing reserves and protected areas.     

THE FEASIBILITY OF USING VERTICAL-LOOKING RADAR TO MONITOR THE MIGRATION OF BROWN PLANTHOPPER AND OTHER INSECT PESTS OF RICE IN CHINA

Abstract The recent development of automatically operating, inexpensive vertical-looking radar (VLR) for entomological purposes has made it practical to carry out routine, automated monitoring of insect aerial migration throughout the year. In this paper we investigate whether such radars might have a role in monitoring and forecasting schemes designed to improve the management of the Brown Planthopper (BPH), Nilaparvata lugens , and of associated rice pest species in China. A survey of the literature revealed that these insects typically migrate at altitudes between 300 to 2 000 m above ground level, but calculations based on BPH radar scattering cross-sections indicated that the maximum altitude at which they individually produce signals analysable by current VLRs is only ˜ 240 m. We also show that coverage over most of the flight altitudes of BPH could be achieved by building a VLR using a wavelength of 8.8 mm instead of the 3.2 cm of existing VLR, but that such a radar would be expensive to build and to operate. We suggest that a more practical solution would be to use a 3.2 cm VLR as a monitor of the aerial movement of the larger species, from which the migration of rice pests in general might be inferred.     

Spatial and temporal pattern of colonization of Nabidae (Heteroptera) in alfalfa (Medicago sativa)

Abstract: Six species of Nabidae (Heteroptera) were collected by standardized sweep net sampling in alfalfa fields in Thuringia, Germany, from 1993 to 1995: Nabis pseudoferus , N. ferus , N. brevis , N. major , Nabicula flavomarginata and Aptus mirmicoides . Colonization of a newly cultivated field was studied over a 3-year period. The density of all the studied nabid species was low (less than five individuals per 100 sweeps) and not related to time since colonization started, or to the distance from the margin of the field. Macropterous species were able to colonize the whole field within one season. The density of one macropterous species, N. pseudoferus , varied between the years of study and was mainly affected by the harvest regime. The brachypterous species reached the margin within one season but for density it took three seasons to reach satiated values also in the centre of the field. The abundance of the brachypterous N. brevis was significantly different both between years and sampling sites. This indicates the importance of the surroundings on the succession of this species. Nabis major , a fully winged species, showed a migration pattern intermediate to macropterous and brachypterous nabids. These results suggest that the total abundance of nabid predators cannot be predicted by time or distance from the expansion source (shelter belts). The abundance of brachypterous nabid individuals can be predicted from time since colonization but is best analysed at the species level.     

Heterogeneic modulation of malignant behavior in human glioma cells in defined and serum-containing media

Summary Malignant features in three glioma cell lines were studied in four defined media of various complexity. The cell lines D37MG, D54MG, and GaMG were able to grow in monolayer culture in all media examined, and as multicellular tumor spheroids in the two most nutrient-rich media. In the defined media, none of the cell lines were able to migrate in a migration assay on poly-D-lysine-coated plastic surfaces. Flow cytometric analysis of the GaMG cell line demonstrated no medium-dependent selection of subclones of glioma cells in spheroids cultured for 30 d. Morphological diversity of spheroids varied according to the supplementation of the media. The capacity of glioma cells to invade cellular rat brain aggregates was intact in the media examined. However, glioma migration was severely inhibited by the lack of specific serum components. This study demonstrates that glioma growth and invasion was heterogenously preserved in the defined media used. Depending on the assay to be used in the study of glioma cell behavior, the degree of medium supplementation has to be considered.     

Stimulation of endothelial cell migration in culture by ladsin,a laminin-5-like cell adhesion protein

Summary Ladsin is a laminin-like cell-adhesive scatter factor with potent cell motility-stimulating ability and was purified from serum-free conditioned medium of a malignant human gastric adenocarcinoma cell line STKM-1. To test its possible role in tumor angiogenesis, we investigated its effect on primary culture of endothelial cells (human umbilical vein endothelial cells) and endothelial cell line ECV304 in this study. Cell adhesion and motility effects of ladsin were observed in both types of endothelial cells. In cell-attachment assay, ladsin interacted with integrin α3β1 that was expressed on the endothelial cell surface. In Boyden chambers, ladsin stimulated both directed and random migration of ECV304 cells. Ladsin induced repair of artificial wounds generated in ECV304 cell monolayers by stimulating cell migration. Ladsin did not affect the growth rate of ECV304 cells at a low cell density but significantly increased the saturation cell density. These results suggest that ladsin may be involved in the adhesion and migration of endothelial cells under some physiological and pathological conditions.     

Acyl Group Migrations in 2-Monoolein

Acyl migration in 2-monoolein dissolved in solvents under conditions common in lipid modification reactions has been studied. The effects on acyl migration of solvent, incubation temperature, water activity, polar additives and solid additives have been investigated. Extensive acyl migration occured in aliphatic hydrocarbons and water-miscible alcohols under dry conditions. The acyl migration rate could be decreased in several nonpolar solvents by adding a small amount of water or an alcohol. Increasing water activity had no effect in isooctane, but decreased the acyl migration rate dramatically in methyl tert-butyl ether and methyl isobutyl ketone. Several commonly used enzyme supports catalysed acyl migration, showing that supports with surface charges could catalyse acyl migration.     

Population structure in Mediterranean islands and risk of genetic invasion in Culexpipiens L. (Diptera: Culicidae)

The mosquito Culex pipiens is subjected to organophosphate treatments in both Corsica and southern Sardinia, but the resistance gene A2-B2, which is currently in a worldwide expansion, has only reached Sardinia. In order to understand this situation, the genetic structure of populations sampled in Sardinia and Corsica was assessed using 15 isozymes. Two loci (HK1 and HK2) were not taken into account because of the possibility of selection. For trie other loci, statistical independence was not rejected for all possible pairs, and no deviation from Hardy-Weinberg expectations was apparent. Low but significant genie differentiation was present between Corsica and Sardinia, as well as between northern and southern Sardinia, despite a large number of effective migrants per generation. These results are discussed in the context of the high probability of extinction/recolonization of breeding sites, the flight migration ability of this mosquito, and the pleiotropic cost of insecticide resistances genes. It is concluded that A2-B2 resistance is unlikely to reach Corsica from southern Sardinia, unless accidental human transportation occurs.