海南东寨港发现斑胸滨鹬

正2013年11月15日上午,在海南省海口市东寨港国家级自然保护区周边一片农田(19°53'51.80″N,116°37'01.78″E)观察到1只斑胸滨鹬(Calidris melanotos)(图1),该片农田用作种植蔬菜和饲养水蚤。发现斑胸滨鹬的同时,也记录到林鹬(Tringa glareola)、泽鹬(T.stagnatilis)、白腰草鹬(T.ochropus)、黑尾塍鹬(Limosa     

湖北武汉发现长嘴半蹼鹬

正2014年4月7至25日,在湖北省武汉市江夏区汤逊湖千亩塘(30°26'48″N,114°24'27″E)观测到长嘴半蹼鹬(Limnodromus scolopaceus)1只,隶属于鸻形目鹬科半蹼鹬属。该鹬被发现于一大型荷塘内,同域分布有扇尾沙锥(Gallinago gallinago)、林鹬(Tringa glareola)、鹤鹬(T.erythropus)、泽鹬(T.stagnatilis)等鹬科鸟种。借助蔡司60倍单筒望远镜观察,并拍摄下图片及视频后发现,该鹬中等体型,与扇尾沙锥近似,但比鹤鹬小。具长而粗的嘴,全嘴色深。白色眉纹明显。上体体羽深褐色,具浅色羽缘。尾上覆羽具横斑。下体色浅,胸     

山东省滨州市发现极危鸟类——勺嘴鹬

正2017年5月18日中午12时,在山东省滨州贝壳堤岛与湿地国家级自然保护区大口河监管站外围滨海湿地(117°52'5″E,38°15'52″N)观测到勺嘴鹬Calidris pygmaea1只。勺嘴鹬隶属于鸻形目Charadriiformes鹬科Scolopacidae滨鹬属Calidris(GibsonAllan,2012;郑光美,2017),被列为世界自然保护联盟(IUCN)红色名录极危(CR)物种(BirdL ife International,2018; IUCN,2018)。该鸟种发现之处为保护区内退潮后的淤泥质滩涂,贝类等底栖生物资源丰     

陕西省鸟类新纪录——小滨鹬

正2017年10月3日,笔者在陕西省定边县苟池(107°30'48″E,34°15'46″N)观察到8只小滨鹬Calidris minuta。经查阅《中国鸟类野外手册》(约翰·马敬能等,2000)、《中国鸟类志》(赵正阶,2001)、《中国鸟类分类与分布名录(第三版)》(郑光美,2017)等相关学术著作及网络数据库,确认其为陕西省鸟类新纪录。小滨鹬属鸻形目Charadriiformes鹬科Scolopacidae。观察时,其在苟池(咸水)的水边觅食,进食时快速跑动,用嘴快速啄食     

云南蒙自长桥海发现秃鹳和翻石鹬

正2013年9月4日,云南省红河州蒙自市长桥海(23°25'42″N,103°23'20″E,海拔1 282 m)发现秃鹳(Leptoptilos javanicus)1只和翻石鹬(Arenaria interpres)4只。其中后者经查阅《中国鸟类分类与分布名录》、《云南鸟类志(上卷)》、《中国鸟类野外手册》等资料,确定为云南鸟类新纪录。秃鹳为体型硕大(体长110 cm)的鸟,比同域分布的钳嘴鹳(Anastomus oscitans)、苍鹭(Ardea     

陕西省鸟类新纪录——红颈瓣蹼鹬和尖尾滨鹬

正2012—2015年在对陕西省蒲城卤阳湖国家湿地公园(109°23'24″~109°35'09″E,34°47'41″~34°50'07″N)进行鸟类调查期间陆续发现了一些陕西省新分布鸟类,其中有2种于2014年8月23日和2015年8月11日拍摄到了清晰的照片,根据其外部形态特征,经查阅《中国鸟类野外手册》(马敬能等,2000)和《中国鸟类志》(赵正阶,2001),分别确定为红颈瓣蹼鹬Phalaropus lobatus和尖尾滨鹬Calidris acuminata。据《中国鸟类分类与分布名录(第二版)》(郑光美,2011)以及相关文献,并检索中国     

四川省鸟类新纪录——灰尾漂鹬

<正>2013年9月26日14∶00左右,笔者在四川省雅安市天全县向阳村五组(30°03'11″N,102°45'23″E,海拔736 m)发现并拍摄水鸟一只。经鉴定,确认为鸻形目Charadriiformes鹬科Scolopacidae的灰尾漂鹬Heteroscelus brevipes,为四川省鸟类一新纪录。该鸟嘴粗且直,鼻沟为嘴长的一半;过眼纹黑色,眉纹白;颏近白,上体体羽全灰,胸浅灰,腹白;脚较短而粗,黄色(马敬能等,     

西藏札达发现印度寿带

正在开展西藏第二次陆生野生动物资源调查工作过程中,于2015年6月18、19日在西藏自治区札达县底雅乡什布奇村(78°44'45.6″E,31°48'33.8″N,3110 m)、6月19日在底雅乡底雅村(78°52'5.1″E,31°46'55.5″N,2977 m)观察并拍摄到雌性印度寿带各1只。经鉴定,为印度寿带印巴亚种Terpsiphone paradisi leucogaster(图1)。     

东北地区鸟类新纪录——长嘴半蹼鹬

<正>笔者于2012年5月5日11∶48,在黑龙江省大庆市龙凤湿地自然保护区(51°23'28.2″N,122°03'32.9″E)拍摄到1只长嘴半蹼鹬Limnodromus scolopaceus,经查阅《黑龙江省鸟类志》《东北鸟类》《东北鸟类图鉴》《中国鸟类区系纲要》《吉林省野生动物图鉴(鸟类)》《辽宁省动物志(鸟类)》《中国鸟类分布与分布名录(第2版)》等文献资料后认定,长嘴半蹼鹬为东北地区的鸟类新纪录。拍摄时该鸟正在觅食。该鸟体长约30 cm。嘴长而直,约9 cm,黑色,嘴基部较前端颜色略淡一些。具白色眼圈、黑棕色贯眼纹。背部呈黑、褐色     

河北沿海发现小凤头燕鸥

正2017年7月25日,在河北省唐山市海港开发区金沙岛一季节性水塘(39°10′26″N,118°58′16″E)观察到1只小凤头燕鸥(Thalasseus bengalensis),该鸟停歇约10 min后飞离该地。至8月7日,在该地点多次记录到单只小凤头燕鸥停歇洗浴。附近亦有普通燕鸥(Sterna hirundo)、白额燕鸥(S.albifrons)、反嘴鹬(Recurvirostra avosetta)、环颈鸻(Charadrius alexandrinus)、青脚滨鹬(Calidris temminckii)等水鸟在此停歇或觅食。所发现的小凤头燕鸥     

水稻小穗轴维管系统网络结构探讨

对籼型、粳型或其不育系与保持系代表品种小穗解剖观察表明：水稻小穗轴维管系统网络由中央维管束和各分枝维管束复合而成。来自小穗柄的１条大的中央主束和几条边围维管束经数次分枝、联结,不断产生新的分枝维管束进入相应的结构。一般颖片中维管束１－２条,第一稃片中１－３条,第二稃片中１－４条,第二朵退化小花残余结构中０－３条,顶生可孕小花的外稃中５条,内稃中３条,浆片中各２条,雄蕊中各１条,雌蕊中３条,主束与支     

Role of eIF3a (eIF3 p170) in intestinal cell differentiation and its association with early development

Eukaryotic initiation factor 3a (eIF3a) has been suggested to play a regulatory role in mRNA translation. Decreased eIF3a expression has been observed in differentiated cells while higher levels have been observed in cancer cells. However, whether eIF3a plays any role in differentiation and development is currently unknown. Here, we investigated eIF3a expression during mouse development and its role in differentiation of colon epithelial cells. We found that eIF3a expression was higher in fetal tissues compared with postnatal ones. Its expression in intestine, stomach, and lung abruptly stopped on the 18th day in gestation but persisted in liver, kidney, and heart throughout the postnatal stage at decreased levels. Similarly, eIF3a expression in colon cancer cell lines, HT-29 and Caco-2, drastically decreased prior to differentiation. Enforced eIF3a expression inhibited while knocking it down using small interference RNA promoted Caco-2 differentiation. Thus, eIF3a may play some roles in development and differentiation and that the decreased eIF3a expression may be a pre-requisite of intestinal epithelial cell differentiation.     

Tonic effects of stationary luminous slits on the discharge rates of some locust visual interneurones

The presence of an illuminated slit in the visual field of a locust compound eye produced changes in the tonic discharge rate of the DCMD and three other visual interneurones, recorded in a connective. The DCMD discharge peaked initially in the range of low slit subtenses, but over a period of minutes of exposure its character changed so that there was a rise at high subtenses also. When the luminance of a slit of fixed subtense was increased in steps, there was an initial rise then a sharp fall in discharge, indicating an abrupt onset of inhibition. Lateral spread of inhibition could account for the peak in response to slits, at a subtense falling well within the acceptance angle of a single ommatidium. The results show the ability of some visual interneurones to maintain a changed level of discharge in the presence of a stationary object in the visual field of the eye.     

Short Communication: The effect of CYP1A1 induction on the formation of benzo a pyrene adducts in liver and lung DNA and plasma albumin in rats exposed to benzo a pyrene:adduct quantitation by immunoassay and an HPLC method

Induction of cytochrome P450 enzymes by exposure to polycyclic aromatic hydrocarbons (PAH) can result in both decreased or increased PAH adduct levels. The lung is a main target site for PAH-carcinogenesis. By HPLC determination of B[ a]P-r-7, t-8-dihydrodiol, t-9, 10-epoxide (BPDE-I)-DNA adducts in rat, the level of the ultimate carcinogenic B[a]P-metabolite was higher in lungs than in liver. However, measured by immunoassay, the total benzo[a]pyrene (B[a]P)-DNA adduct levels were higher in liver than in lungs. Induction of CYP1A1 in vivo in rat by repeated i.p. doses of methylcholanthrene (MC) prior to a single dose of B[a]P resulted in a 2.4 times increase in CYP1A1 activity in liver tissue and 1.5 times higher levelsof total B[a]P-DNA adducts in lung and liver compared with controls which only received B[a]P. Increased levels of BPDE-I-DNA adducts were significantly correlated to increased CYP1A1 activity in induced lung tissue but not in liver. The times to reach maximum adduct levels were similar for both controls and MC-induced rats in both lung and liver,and plasma albumin. The BPDE-I-albumin adducts reached a maximum level around 1 day after B[a]P exposure and could not be used as a reliable marker of the short term PAH exposure in this study.     

Kinetic Origin of Heredity in a Replicating System with a Catalytic Network

The origin of heredity is studied as a recursive state in a replicatingprotocell consisting of many molecule species in mutually catalyzingreaction networks. Protocells divide when the number of molecules, increasing due to replication, exceeds a certain threshold. We study how the chemicals in a catalytic network can form recursive production states in the presence of errors in the replication process. Depending on the balance between the total number of molecules in a cell and the number of molecule species, we have found three phases; a phase without a recursive production state, a phase with itinerancy over a few recursive states, and a phase with fixedrecursive production states. Heredity is realized in the latter two phaseswhere molecule species that are population-wise in the minority are preserved and control the phenotype of the cell. It is shown that evolvability is realized in the itinerancy phase, where a change in the number of minority molecules controls a change of the chemical state.     

Spatial and temporal coordination of traction forces in one-dimensional cell migration

ABSTRACT

Migration of a fibroblast along a collagen fiber can be regarded as cell locomotion in one-dimension (1D). In this process, a cell protrudes forward, forms a new adhesion, produces traction forces, and releases its rear adhesion in order to advance itself along a path. However, how a cell coordinates its adhesion formation, traction forces, and rear release in 1D migration is unclear. Here, we studied fibroblasts migrating along a line of microposts. We found that when the front of a cell protruded onto a new micropost, the traction force produced at its front increased steadily, but did so without a temporal correlation in the force at its rear. Instead, the force at the front coordinated with a decrease in force at the micropost behind the front. A similar correlation in traction forces also occurred at the rear of a cell, where a decrease in force due to adhesion detachment corresponded to an increase in force at the micropost ahead of the rear. Analysis with a bio-chemo-mechanical model for traction forces and adhesion dynamics indicated that the observed relationship between traction forces at the front and back of a cell is possible only when cellular elasticity is lower than the elasticity of the cellular environment.     

Ubiquitin-specific cysteine protease 2a (USP2a) regulates the stability of Aurora-A

The ubiquitin/proteasome pathway plays critical roles in virtually all aspects of cell biology. Enzymes of the ubiquitin pathway add (ligases) or remove (deubiquitinases) ubiquitin tags to or from their target proteins in a selective fashion. USP2a is a member of a subfamily of deubiquitinases, called ubiquitin-specific cysteine proteases (USPs). Although USP2a has been reported to be a bona fide oncogene that regulates the stability of MDM2, MDMX, and FAS, it is likely that there are other unidentified substrates for USP2a. In this study, we show that USP2a mediates mitotic progression by regulating the stability of Aurora-A. Through cell-based screening of a USP siRNA library, we discovered that knockdown of USP2a reduced the protein levels of Aurora-A. USP2a interacts with Aurora-A directly in vitro and in vivo. In addition, Aurora-A is a substrate for USP2a in vitro and in vivo. Our study provides a novel mechanism for the role of USP2a in mediating the stability of Aurora-A.     

Semaphorin 2a secreted by oenocytes signals through plexin B and plexin A to guide sensory axons in the Drosophila embryo

The semaphorin gene family has been shown to play important roles in axonal guidance in both vertebrates and invertebrates. Both transmembrane (Sema1a, Sema1b, Sema5c) and secreted (Sema2a, Sema2b) forms of semaphorins exist in Drosophila. Two Sema receptors, plexins (Plex) A and B, have also been identified. Many questions remain concerning the axon guidance functions of the secreted semaphorins, including the identity of their receptors. We have used the well-characterized sensory system of the Drosophila embryo to address these problems. We find novel sensory axon defects in sema2a loss-of-function mutants in which particular axons misproject and follow inappropriate pathways to the CNS. plexB loss-of-function mutants show similar phenotypes to sema2a mutants and sema2a interacts genetically with plexB, supporting the hypothesis that Sema2a signals through PlexB receptors. Sema2a protein is expressed by larval oenocytes, a cluster of secretory cells in the lateral region of the embryo and the sema2a mutant phenotype can be rescued by driving Sema2a in these cells. Ablation of oenocytes results in sensory axon defects similar to the sema2a mutant phenotype. These data support a model in which Sema2a, while being secreted from oenocytes, acts in a highly localized fashion: It represses axon extension from the sensory neuron cell body, but only in regions in direct contact with oenocytes.     

Wnt7a,frequently silenced by CpG methylation,inhibits tumor growth and metastasis via suppressing epithelial-mesenchymal transition in gastric cancer

Wnt7a is a member of the Wnt family and has been reported to be involved in the carcinogenesis and progression of many types of human cancer. However, little is known about Wnt7a expression and function in gastric cancer (GC). In the present study, Wnt7a expression in GC tissues and cells was investigated, the correlation between Wnt7a expression and the prognosis was also examined. The effects of Wnt7a on proliferation, invasion, and metastasis were evaluated in vitro and in vivo. Furthermore, the expression of epithelial-mesenchymal transition (EMT) markers and hypermethylation of the Wnt7a promoter were both detected. Wnt7a was downregulated in GC and its expression was associated with poor prognosis of patients with GC. Moreover, upregulation of Wnt7a significantly suppressed the growth, invasion, and metastasis abilities of GC cells in vitro and in vivo. Mechanistically, Wnt7a was found to inhibit EMT process of GC cells. In addition, the reducing expression of Wnt7a was due to methylation of 5′-CpG island within the promoter. Furthermore, the tumor suppressor role of Wnt7a is independent of canonical Wnt/β-catenin signaling in GC cells. In conclusion, our findings demonstrated that Wnt7a could be used as a potential diagnostic marker and target for GC management.