四川牛羚的分布

本文分析讨论了目前牛羚在四川的分布格局及其原因,并提出了相应的保护措施。     

中国龟鳖动物的分布

本文依据1997年以来的文献,对中国龟鳖动物新增加的分布作了归纳和讨论;并对中国龟鳖动物的分布区系及特征作了初步分析和总结.     

桃花水母

介绍了桃花水母的生活习性、形态、生理、分类、分布,讨论了桃花水母的研究意义及经济价值。     

F分布与物种总数的统计推断

通过两点分布和几何分布模型,给出了物种总数N的点估计,并讨论了它的性质．根据F分布和二项分布、几何分布的关系,本文得到了N的区间估计和检验统计量．     

湖南省的龟鳖目动物

根据历年在湖南省各地采集的标本及查阅文献记录,归纳出湖南省龟鳖目动物名录４种１０种。工作中核对了原始记录和标本,并长期饲养观察,对所有记录进行了客观地评价。讨论了当前情况下确定龟鳖类分布的原则以及本报道在中国龟鳖目分布方面的意义。     

中国浦公英属植物的初步整理

报导了我国蒲公英属植物的分类、分布及主要经济用途,也略讨论了该属植物的起源与区系地理等。     

木耳属植物资源的保健功效及其开发利用

本文报道了我国木耳属植物的分布 ;子实体的营养成分 ;活性物质 -多糖的生理功能。讨论了开发利用木耳属植物资源的问题 ,提出了有关建议     

厦门附近海域浮游甲藻类的分布

本文报道了厦门附近海域浮游甲藻类49种,并对其生态特性以及与海洋环境因素的关系进行了详细研究与讨论。分析的204号样品,系1980年9月至1981年8月,逐月采自厦门海域的浔江区(Ⅰ区),西港区(Ⅱ区)和九龙江口区(Ⅱ区)。     

黑龙江省的粘菌：I.凉水自然保护区粘菌种类分布

本文首次报告了凉水自然保护区粘菌７科１５属３５种。３属：筛菌属Ｃｒｉｂｒａｒｉａ,筒菌属Ｔｕｂｉｆｅｒａ及亮皮菌属Ｌａｍｐｒｏｄｅｒｍａ为黑龙江省新记录属,１８种为黑龙江省新记录种,其中红筛菌Ｃｒｉｂｒａｒｉａ ｅｌｅｇａｎｓ是中国新记录种,并作了形态描述;同时讨论了该地区有关属种的分布特点。     

中国珍稀濒危保护植物在江苏省的自然分布及其特点

讨论了１７种中国珍稀濒危植物在江苏省的自然分布及其特点,它们分别为小叶银缕梅（Ｐａｒｒｏｔｉａ ｓｕｂａｅｑｕａｌｉｓ）、宝华玉兰（Ｍａｇｎｏｌｉａ ｚｅｎｉｉ）、天目木兰（Ｍａｇｎｏｌｉａ ａｍｅｏｎａ）、秤钎锤树（Ｓｉｎｏｊａｃｋｉａｘｙｌａｃａｒｐａ）、明党参（Ｃｈａｎｇｉｕｍ ｓｍｙｒｎｉｏｉｄｅｓ）、珊瑚苯（Ｇｌｅｈｎｉａ ｌｉｔｔｏｒａｌｉｓ）、独花兰（Ｃｈａｎｇｎｉｅｎｉａ ａｍｏ     

ULTRASTRUCTURE AND SYSTEMATICS OF TWO NEW FRESHWATER RED CRYPTOMONADS, STOREATULA RHINOSA, SP. NOV. AND PYRENOMONAS OVALIS, SP. NOV.

The ultrastructure and systematics of two red colored freshwater cryptomonads, Storeatula rhinosa , sp. nov. and Pyrenomonas ovalis , sp. nov., are described for the first time. Storeatula, which had been described from marine waters only, has a single inner periplast sheet and a fibrous surface periplast component. Cells lack a furrow but possess a gullet, a bilobed chloroplast connected by a pyrenoid and a nucleomorph located in an indentation of the pyrenoid. This freshwater Storeatula possesses the same general features as the marine species, but it has a contractile vacuole and lacks the lobed chloroplast of S. major. P. ovalis has the generic characteristics described for marine species of Rhodomonas. These characteristics include a short furrow, a deep gullet, square inner periplast plates with beveled corners, a slightly fibrillar surface periplast component, a single chloroplast with two lobes connected by a pyrenoidal bridge and a nucleomorph located in an indentation of the pyrenoid.     

Multifaceted functions of RPS27a: An unconventional ribosomal protein

The ribosomal protein S27a (RPS27a) is cleaved from the fusion protein ubiquitin–RPS27a (Ub–RPS27a). Generally, Ub and RPS27a are coexpressed as a fusion protein but function independently after Ub is cleaved from RPS27a by a deubiquitinating enzyme. As an RP, RPS27a assembles into ribosomes, but it also functions independently of ribosomes. RPS27a is involved in the development and poor prognosis of various cancers, such as colorectal cancer, liver cancer, chronic myeloid leukemia, and renal carcinoma, and is associated with poor prognosis. Notably, the murine double minute 2/P53 axis is a major pathway through which RPS27a regulates cancer development. Moreover, RPS27a maintains sperm motility, regulates winged aphid indirect flight muscle degeneration, and facilitates plant growth. Additionally, RPS27a is a metalloprotein and mercury (Hg) biomarker. In the present review, we described the origin, structure, and biological functions of RPS27a.     

A system for coupled multiple-column separation of proteins

Purification of proteins is commonly a multiple-step process involving size exclusion, ion exchange, affinity, hydrophobic, and other modes of chromatography. In an effort to circumvent the laborious process of collecting the solutes from each column and reintroducing them onto a second column, a valving system is described that directs the samples eluted from a high-performance liquid chromatographic column through a detector with a high-pressure cell into either a second column or into storage loops of a multiloop value. This multiloop value is referred to as a high-pressure fraction collector. After development of the first column is complete, a second solvent can be directed to the second column or high-pressure fraction collector to elute the solutes back through the detector and onto any other column in the system. The process of eluting a sample from a column through a single detector and directing it to the high-pressure fraction collector or any other column in the system may be repeated a number of times. Such valving systems make it possible to chromatograph a single protein component on two or three columns in a short time.     

Munc18a controls SNARE assembly through its interaction with the syntaxin N-peptide

Sec1/Munc18-like (SM) proteins functionally interact with SNARE proteins in vesicular fusion. Despite their high sequence conservation, structurally disparate binding modes for SM proteins with syntaxins have been observed. Several SM proteins appear to bind only to a short peptide present at the N terminus of syntaxin, designated the N-peptide, while Munc18a binds to a 'closed' conformation formed by the remaining portion of syntaxin 1a. Here, we show that the syntaxin 16 N-peptide binds to the SM protein Vps45, but the remainder of syntaxin 16 strongly enhances the affinity of the interaction. Likewise, the N-peptide of syntaxin 1a serves as a second binding site in the Munc18a/syntaxin 1a complex. When the syntaxin 1a N-peptide is bound to Munc18a, SNARE complex formation is blocked. Removal of the N-peptide enables binding of syntaxin 1a to its partner SNARE SNAP-25, while still bound to Munc18a. This suggests that Munc18a controls the accessibility of syntaxin 1a to its partners, a role that might be common to all SM proteins.     

黑犀(奇蹄目,犀科)化石在中国的首次发现

黑犀(Diceros属)的惟一现生代表D.bicornis生活在非洲。该属在新近纪时期曾广泛分布于希腊、土耳其和伊朗等地区,但从未在东亚地区发现过。新种甘肃黑犀(Diceros gan- suensis sp.nov.)是该属在中国和东亚的首次发现。化石采自甘肃临夏盆地晚中新世柳树组中部。新种以尺寸较小、头型短、枕顶高耸、枕面窄而高、枕嵴无中沟、副枕突短小、下颌上升支距m3较近、前臼齿较小、DP1无后脊、P2原脊孤立、P2和P3后脊细窄而区别于东地中海地区的Diceros neumayri。D.neumayri的分类位置一直是一个争论的焦点,曾在黑犀(Diceros属)和白犀(Ceratotherium属)之间反复变更。研究显示,甘肃黑犀和D.neumayri的一系列共同的原始特征表明它们与更进步的白犀有明显的区别,应该归入黑犀属。     

A reduced muscle model and planar musculoskeletal model fit for the simulation of whole-body movements

Musculoskeletal models are made to reflect the capacities of the human body in general, and often a specific subject in particular. It remains challenging to both model the musculoskeletal system and then fit the modelled muscles to a specific human subject. We present a reduced muscle model, a planar musculoskeletal model, and a fitting method that can be used to find a feasible set of active and passive muscle parameters for a specific subject. At a minimum, the fitting method requires inverse dynamics data of the subject, a scalar estimate of the peak activation reached during the movement, and a plausible initial estimate for the strength and flexibility of that subject. While additional data can be used to result in a more accurate fit, this data is not required for the method solve for a feasible fit. The minimal input requirements of the proposed fitting method make it well suited for subjects who cannot undergo a maximum voluntary contraction trial, or for whom recording electromyographic data is not possible. To evaluate the model and fitting method we adjust the musculoskeletal model so that it can perform an experimentally recorded stoop-lift of a 15 kg box.     

The puncta enigma

This Editor's Corner may sound like the title of a mystery novel, but it actually reflects a question I have about the puncta articles that appear in Autophagy (or rather, the ones that do not appear). In particular, I am surprised by the number of solicitations sent out for puncta that are either ignored, or, less frequently, declined. It is not that I expect the principal investigator (PI) to find the invitation to write a punctum undeniably attractive. Rather, it is the unilateral decision that it is not worthwhile for graduate students or postdocs who performed the work—and likely wrote at least the first draft of the paper—to write the punctum. In fact, time spent drafting a punctum yields considerable benefits: puncta provide more exposure for the lab, offer opportunities for young scientists to gain additional writing experience, and make a nice (albeit small) addition to a curriculum vitae. It is for the latter reason that I find it particularly disappointing that PIs decide to dismiss the opportunity to write a punctum. I fully understand that for many PIs, adding a punctum will not have a significant impact on a curriculum vitae. Yet for a student or a postdoc who might have a relatively small number of publications at this stage of their career, a punctum (even though it is not a full-fledged research article) can have a more meaningful impact on their C.V.     

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.     

Tumor suppressor and aging biomarker p16(INK4a) induces cellular senescence without the associated inflammatory secretory phenotype

Cellular senescence suppresses cancer by preventing the proliferation of cells that experience potentially oncogenic stimuli. Senescent cells often express p16(INK4a), a cyclin-dependent kinase inhibitor, tumor suppressor, and biomarker of aging, which renders the senescence growth arrest irreversible. Senescent cells also acquire a complex phenotype that includes the secretion of many cytokines, growth factors, and proteases, termed a senescence-associated secretory phenotype (SASP). The SASP is proposed to underlie age-related pathologies, including, ironically, late life cancer. Here, we show that ectopic expression of p16(INK4a) and another cyclin-dependent kinase inhibitor, p21(CIP1/WAF1), induces senescence without a SASP, even though they induced other features of senescence, including a stable growth arrest. Additionally, human fibroblasts induced to senesce by ionizing radiation or oncogenic RAS developed a SASP regardless of whether they expressed p16(INK4a). Cells induced to senesce by ectopic p16(INK4a) expression lacked paracrine activity on epithelial cells, consistent with the absence of a functional SASP. Nonetheless, expression of p16(INK4a) by cells undergoing replicative senescence limited the accumulation of DNA damage and premature cytokine secretion, suggesting an indirect role for p16(INK4a) in suppressing the SASP. These findings suggest that p16(INK4a)-positive cells may not always harbor a SASP in vivo and, furthermore, that the SASP is not a consequence of p16(INK4a) activation or senescence per se, but rather is a damage response that is separable from the growth arrest.