转录因子SOX2 对胃癌干细胞自我更新、增殖和迁移的影响

目的:检测SOX2在胃癌组织中的表达,探讨SOX2对胃癌干细胞自我更新、增殖和转移能力的影响。方法:采用免疫组化检测SOX2在胃癌及癌旁组织中的表达情况。通过肿瘤球形成实验富集、分离胃癌干细胞。构建SOX2过表达慢病毒并感染胃癌干细胞中,通过实时定量PCR和western bolt检测感染慢病毒后胃癌干细胞中SOX2表达情况。分别利用肿瘤球形成实验检测SOX2对胃癌肿瘤干细胞自我更新能力的影响,CCK-8实验检测SOX2对胃癌干细胞增殖能力的影响,流式细胞术分析SOX2对胃癌干细胞的细胞周期的影响,Transwell实验检测SOX2对胃癌干细胞转移能力的影响。结果:SOX2在胃癌组织中表达显著低于癌旁组织。肿瘤球形成实验能够有效富集胃癌细胞SGC-7901和BGC-823的干细胞。慢病毒载体感染能够显著增强SOX2在胃癌干细胞中的表达。过表达SOX2能够抑制胃癌干细胞的自我更新、增殖和侵袭能力。结论:SOX2在胃癌中发挥抑癌基因的功能,其机制可能通过抑制肿瘤干细胞的自我更新、增殖和侵袭转移能力而抑制胃癌的发生发展。     

兴凯湖湿地丹顶鹤迁徙与繁殖数量调查

兴凯湖作为亚太地区水鸟重要的迁徙停歇地以及繁殖地,对丹顶鹤(Grus japonensis)的局域保护有着重要意义。2012~2014年通过样点与样线相结合的方法对兴凯湖保护区春、秋两季丹顶鹤的迁徙数量以及夏季的繁殖数量进行了调查。这3年中兴凯湖地区丹顶鹤的迁徙数量较为稳定,春季迁徙数量51~84只,秋季迁徙数量178~213只;繁殖个体数量呈轻微下降趋势,由2012年的105只下降至2014年的83只;栖息本地的丹顶鹤数量有了明显的增多,2013和2014年分别增长15和9只。丹顶鹤数量调查对了解其地理分布和种群数量变动规律具有重要意义,也为制订保护措施提供科学依据。     

Timing of glucocorticoid administration determines severity of lipid metabolism and behavioral effects in rats

Glucocorticoids (GCs) are a group of steroid hormones secreted by the adrenal glands in circadian cycles, and the dysregulation of GC signaling has been suggested to cause metabolic syndrome. Even though prolonged GC exposure is associated with serious side effects such as metabolic syndrome and central nervous system disorders, the use of GCs in anti-inflammatory and immunosuppressive therapies has been continuously rising. Meanwhile, the exact mechanisms by which GCs can influence the lipid metabolism as well as behavior and how they are affected by time remain unknown. In this study, the effects of two different long-term GC dosing regimens on lipid metabolism and behavior were investigated. Male Wistar rats received daily administrations of the GC dexamethasone sodium phosphate (DEX, 0.5 mg/kg body weight) at either ZT0 (Dex0) or ZT12 (Dex12). After 6 weeks of treatment, DEX-treated rats, especially those treated at ZT0, had higher hepatic lipid accumulation and serum triglyceride levels and less locomotor activity than did control rats. In addition, serum levels of corticosterone, 5-hydroxy tryptamine and norepinephrine were decreased in the Dex0 group but not in the Dex12 group compared to the control group. Furthermore, quantitative real-time polymerase chain reaction analysis indicated that the chronic administration of GCs at ZT0 upregulated genes related to glycolysis and lipid synthesis and downregulated genes related to fatty acid β-oxidation in the liver more remarkably than administration at ZT12. Both DEX-treated groups displayed severely altered expression patterns of the core clock genes Bmal1 and Per2 in the liver and in fat. In addition, the expression of glutamate aspartate transporter, glial fibrillary acidic protein and glutamate transporter-1, astrocyte-related genes important for maintaining nervous system functions, was drastically decreased in the hippocampus of DEX-treated rats, especially when DEX was given at ZT0. In conclusion, our findings confirm that the severity of side effects, indicated by altered lipid metabolism and behavioral activity, depends on the timing of GC administration and is associated with the degree of glucocorticoid receptor dysfunction after dosing at disparate time points.     

Season of birth affects juvenile survival of giraffe

Variation in timing of reproduction and subsequent juvenile survival often plays an important role in population dynamics of temperate and boreal ungulates. Tropical ungulates often give birth year round, but survival effects of birth season for tropical ungulate species are unknown. We used a population of giraffe in the Tarangire Ecosystem of northern Tanzania, East Africa to determine whether calf survival varied by season of birth. Variation in juvenile survival according to season of birth was significant, with calves born during the dry season experiencing the highest survival probability. Phenological match may confer a juvenile survival advantage to offspring born during the dry season from greater accumulated maternal energy reserves in mothers who conceive in the long rainy season, high-protein browse in the late dry-early short rainy seasons supplementing maternal and calf resources, reduced predation due to decreased stalking cover, or some combination of these. Asynchrony is believed to be the ancestral state of all ungulates, and this investigation has illustrated how seasonal variation in vegetation can affect juvenile survival and may play a role in the evolution of synchronous births.     

海洋碳迁移转化与主要化学驱动因子的相互关系

分析了化学驱动因子对海洋碳迁移转化过程的影响.海洋碳迁移转化与各种化学驱动因子参与的生物地球化学过程密切相关.营养盐水平、pH、溶解氧浓度（DO）、氧化还原电位（Eh）、SO₄^2-及硫电位（Es）等主要化学驱动因子的消长导致了海洋化学环境的变化,进而对海洋碳的迁移转化产生影响.在营养盐的供给和生物吸收情况良好的海域,CO₂由于光合作用,并通过沉降有机物的氧化,不断被转移到海水深层,使得海水中的CO₂分压（P_CO2）降低,CO₂的海-气交换量和有机碳输出通量增大,从使该海域表现为CO₂的汇.由于CO₂的溶解与吸收以及有机物的降解造成了海洋环境的日益酸化,引起了海水中碳酸盐溶解度增大;沉积物中酸碱环境的变化也与有机物的矿化以及碳酸盐的溶解、沉淀过程密切相关.此外,DO、Eh、SO₄^2-及Es的变化与水体中有机碳的矿化分解过程和碳在沉积层中沉积埋葬过程相耦合.在水体中,高DO、高Eh利于有机碳向无机碳转化;而在DO和Eh较低的沉积环境中,高SO₄^2-不利于有机碳的埋葬与保存.     

Spring migration phenology of birds in the Northern Prairie region is correlated with local climate change

ABSTRACT In apparent response to recent periods of global warming, some migratory birds now arrive earlier at stopover sites and breeding grounds. However, the effects of this warming on arrival times vary among locations and species. Migration timing is generally correlated with temperature, with earlier arrival during warm years than during cold years, so local variation in climate change might produce different effects on migration phenology in different geographic regions. We examined trends in first spring arrival dates (FADs) for 44 species of common migrant birds in South Dakota (1971–2006) and Minnesota (1964–2005) using observations compiled by South Dakota and Minnesota Ornithologists’ Unions. We found significant trends in FAD over time for 20 species (18 arriving earlier and two later) in South Dakota and 16 species (all earlier) in Minnesota. Of these species, 10 showed similar significant trends for both states. All 10 of these species exhibited significantly earlier arrival, and all were early spring migrants, with median FADs before 10 April in both states. Eighteen of the 44 species showed significant negative correlations of FADs with either winter (December–February) or spring (arrival month plus previous month) temperatures in one or both states. Interestingly, spring temperatures in both South Dakota and Minnesota did not warm significantly from 1971–2006, but winter temperatures in both states warmed significantly over the same time period. This suggests that the warmer winters disproportionately affected early spring migrants, especially those associated with aquatic habitats (seven of the 10 species showing significantly earlier spring arrival in both states). The stronger response to climate change by early spring migrants in our study is consistent with the results of several other studies, and suggests that migrants, especially early migrants, are capable of responding to local temperature conditions experienced on wintering grounds or along the migration route.     

Comparative proteomic analysis of mesenchymal stem cells derived from human bone marrow,umbilical cord,and placenta: Implication in the migration

Umbilical cord (UC) and placenta (P) have been suggested as alternatives to bone marrow (BM) as sources of mesenchymal stem cells (MSC) for cell therapy, with both UC‐ and P‐MSC possess immunophenotypic and functional characteristics similar to BM‐MSC. However, their migration capacity, which is indispensable during tissue regeneration process, is unclear. Under defined conditions, the migration capacity of BM‐ and P‐MSC was found 5.9‐ and 3.2‐folds higher than that of UC‐MSC, respectively. By the use of 2‐DE and combined MS and MS/MS analysis, six differentially expressed proteins were identified among these MSC samples, with five of them known to be involved in cell migration as migration enhancing or inhibiting proteins. Consistent with their migration capacity, the levels of migration enhancing proteins including cathepsin B, cathepsin D and prohibitin,were significantly lower in UC‐MSC when compared with those in BM‐ and P‐MSC. For the migration inhibiting proteins such as plasminogen activator inhibitor‐1 (PAI‐1) and manganese superoxide dismutase, higher expression was found in the UC‐MSC. We also showed that the overexpression of the PAI‐1 impaired the migration capacity of BM‐ and P‐MSC while silencing of PAI‐1 enhanced the migration capacity of UC‐MSC. Our study indicates that PAI‐1 and other migration‐related proteins are pivotal in governing the migration capacity of MSC.     

Presence of moose (<Emphasis Type="Italic">Alces alces</Emphasis>) in Southeastern Germany

Germany is situated on the western border of the distribution area of moose (Alces alces) in Europe. In the past, the number of moose sightings has been very limited and irregular in the state of Bavaria (SE Germany). Nearby populations of moose are located in neighboring countries to the east of Germany, in the Czech Republic, and Poland. A monitoring system for moose was established following a considerable increase in moose observations in Bavaria in 2007. As no reproduction has yet been recorded, moose observation has so far been attributed only to migrating individuals. Cows are more often registered than bulls (27 of 35 observations between 2004 and 2008). The reasons for the increase in migratory activities of moose have not yet been identified.     

Variation in the timing of river entry of Atlantic salmon （Salmo salar L. ） in the Baltic

The timing of river entry in the Atlantic salmon is known to depend on genetic, demographic and environmental factors, but little is known about the relative magnitude of among population and among year variation and covariation in this respect in natural state Atlantic salmon rives. To investigate this, variability in the timing of river entry in three historical Finnish Atlantic salmon populations were analyzed using salmon trap data collected during 1870- 1902. The analyses reveled that 1 ） the timing of river entry differed substantially and consistently among the rivers, and that 2） variation among the rivers was much larger than variation among years. Annual variations were not explained by regional environmental conditions, whereas in one river the timing of the local flood peak was a significant predictor of the timing of river entry. Differences in the timing of salmon entry to geographically closely situated rivers suggests that a regionally fixed opening date for coastal fisheries might not be the best management strategy as it may lead to uneven exploitation of salmon populations from different rivers [ Current Zoology 55 （5） ： 342 - 349, 2009] .