The presence of Compsocerops (Brachyopoidea: Chigutisauridae) (Late Triassic) in southern Brazil with comments on chigutisaurid palaeobiogeography

Abstract: Chigutisauridae is the longest‐lived trematosaurian clade (from early Triassic to early Cretaceous). They were reported in Argentina, Australia, India and South Africa. This contribution reports a putative chigutisaurid specimen in the Carnian of southern Brazil (Santa Maria Formation, Paraná Basin). The material comprises two skull fragments, a mandibular fragment, a clavicular blade and a humerus. Ontogenetic features point to an early development stage of the specimen. The presence of a long, straight and pointed tabular horn, which runs parallel to the skull midline towards its tip, and a distinctive projection in the posterior border of the postparietal indicates a close relationship of the Brazilian chigutisaurid with the Indian Compsocerops cosgriffi. Three distinctive and combined characters suggest that the Brazilian chigutisaurid is a distinctive specimen: the presence of an alar process of the jugal in the ventral margin of the orbit; jugal does not extend well beyond the anterior margin of the orbit; and tabular does not contact the parietal. These characters could justify the erection of a new taxon; however, they might reflect its immature ontogenetic stage as well. Accordingly, we attribute this new specimen to Compsocerops sp. Argentinean and Indian occurrences are dated as Norian, so the presence of a Carnian chigutisaurid in southern Brazil indicates that western Gondwana chigutisaurids have first occupied the Paraná Basin and later migrated towards west (to Argentina) and east (India). However, the presence of ghost chigutisaurid taxa cannot be dismissed, because their long temporal range contrasts with their still short (in comparison with other temnospondyl groups) geographic distribution. Hence, they might have been more geographically widespread than their fossil record suggests.     

Middle–Late Permian tetrapods from the Rio do Rasto Formation,Southern Brazil: a biostratigraphic reassessment

Dias‐da‐Silva, S. 2011: Middle–Late Permian tetrapods from the Rio do Rasto Formation, Southern Brazil: a biostratigraphic reassessment. Lethaia, Vol. 45, pp. 109–120. The Rio do Rasto Formation (Permian of Southern Brazil) was previously regarded as Guadalupian–early Lopingian age. Three tetrapod‐based localities are known: the Serra do Cadeado area, Aceguá and Posto Queimado. The latest tetrapod‐based biostratigraphic contribution considers that the Posto Queimado and Aceguá faunas are coeval and Wordian (middle Guadalupian) in age, correlated to the Isheevo faunas from Eastern Europe and to the Tapinocephalus Assemblage Zone of South Africa; whereas the Serra do Cadeado fauna is Capitanian (late Guadalupian), correlated to the Kotelnich fauna of Eastern Europe and, from bottom to top, to upper Pristerognathus, Tropidostoma and lower Cistecephalus assemblage zones of South Africa. A re‐evaluation of the tetrapods from the Rio do Rasto Formation and new fossil discoveries in the localities of Posto Queimado and Serra do Cadeado area (melosaurine and platyoposaurine temnospondyls, a basal anomodont, a dinocephalian and a basal dicynodont) supports a new tetrapod‐based biostratigraphic scheme for the Rio do Rasto Formation. Accordingly, the age of the fauna at Aceguá is late Roadian‐early Wordian, whereas the locality of Posto Queimado is late Wordian‐Capitanian. The Serra do Cadeado Area is correlated with both southernmost ones (Guadalupian) but also Wuchiapinghian (early Lopingian). □Paraná Basin, Passa Dois Group, tetrapod biostratigraphy, Western Gondwana.     

Leaf Blade Dimensions of Rice (Oryza sativa L. and Oryza glaberrima Steud.). Relationships between Tillers and the Main Stem

The effects of genotype and environment on the leaf area indexof rice are well documented, but the rules governing leaf areadistribution among main stem and tillers are less well understood.This study investigated the ontogenetic patterns of leaf bladearea and dimensions on the main stem and tillers of three ricecultivars, IAC47, Javaé (Oryza sativa L.) and CG14 (O.glaberrima Steud.) grown in pots without competition among plants.No differences in phyllochron were observed among culms, butleaves on tillers appeared 0.5 to 0.8 phyllochrons earlier thanthe genealogically corresponding leaves on the main stem (systemof Katayama). Cohorts were thus not fully synchronized. Allculms produced their largest leaves soon after panicle initiation(PI), despite differences in tiller age. Leaves that appearedsubsequently were smaller owing to reduced length but not width,which remained constant. Three different hypothetical rulesgoverning the behaviour of culms were tested: (1) tillers behaveas clones of the main stem; (2) cohorts behave uniformly, and(3) behaviour is determined by leaf position (sum of genealogicalleaf and tiller indices). The results were best explained byhypotheses (2) and (3), with leaf blade width and length showingmarkedly different patterns. Copyright 2001 Annals of BotanyCompany Phenology, phyllochron, leaf area, leaf position, leaf cohorts, summed leaf position, leaf blade length and width     

DEPTOR Is a Stemness Factor That Regulates Pluripotency of Embryonic Stem Cells

The mammalian target of rapamycin (mTOR) pathway regulates stem cell regeneration and differentiation in response to growth factors, nutrients, cellular energetics, and various extrinsic stressors. Inhibition of mTOR activity has been shown to enhance the regenerative potential of pluripotent stem cells. DEPTOR is the only known endogenous inhibitor of all known cellular mTOR functions. We show that DEPTOR plays a key role in maintaining stem cell pluripotency by limiting mTOR activity in undifferentiated embryonic stem cells (ESCs). DEPTOR levels dramatically decrease with differentiation of mouse ESCs, and knockdown of DEPTOR is sufficient to promote ESC differentiation. A strong decrease in DEPTOR expression is also observed during human ESCs differentiation. Furthermore, reduction in DEPTOR level during differentiation is accompanied by a corresponding increase in mTOR complex 1 activity in mouse ESCs. Our data provide evidence that DEPTOR is a novel stemness factor that promotes pluripotency and self-renewal in ESCs by inhibiting mTOR signaling.     

NESTING OF THE VILLAGE WEAVER PLOCEUS CUCULLATUS

From August to October 1975, 31 nesting colonies of Village Weavers were identified within an area of 3000 km², south of Lake Chad in Africa. The number of nests and the productivity of each colony were estimated by means of several samplings made during the course of the nesting season. Differences between bush colonies and village colonies are not relevant. The average length of the nesting season is 70 days. In each colony the number of nests increases during the first month and then decreases. The average number of fledging attempts is four per colony, with a period of about ten days from one to another. On a regional scale, breeding periods and fledging attempts are well synchronized. Each nest carries an average of 2.4 eggs and 1.9 young, the difference occurring only at hatching. Due to regional synchronism, the period of most intensive reproductive activity, at which the number of nests reaches its maximum, can be determined.     

《中国植被志》的植被分类系统、植被类型划分及编排体系

植被志(vegegraphy)是基于植被调查资料, 全面记叙植被的群落外貌、种类组成、结构和功能、生境条件, 以及地理分布等特征, 并对同类植被进行归纳和总结的志书。“植被志”的英文译为“vegegraphy”, 是本文的新造词, 它是由“vegetation”的词头“vege-”和英文后缀“-graphy” (记叙之意)组成的合成词。《中国植被志》的研编是一项时间紧迫、内容复杂、工作量浩繁的重大科学工程。它的完成将极大提升中国植被科学和生态学的研究水平, 并为中国植被资源的合理利用、生物多样性保护及生态环境治理等提供不可或缺的基础资料。本文首先简述了植被的基本特征(主要包括外貌特征、种类组成、群落结构以及动态变化等)和国内外植被调查的进展情况, 简要回顾了中国植被分类系统的研究历史, 并对以往的分类系统进行了若干修订。在此基础上, 着重讨论并提出了《中国植被志》卷册编排体系和用于《中国植被志》研编的植被类型划分方案。在对植被分类系统的修订方面, 主要对高级分类单位及相对应的英文名称进行了讨论和修订。按照本文修订的分类系统, 中国植被的分类单位及其对应的英文名称分别是: 植被型组(Vegetation Formation Group)、植被型(Vegetation Formation)和植被亚型(Vegetation Subformation)、群系组(Alliance Group)、群系(Alliance)和亚群系(Suballiance)、群丛组(Association Group)以及群丛(Association)。在植被型组中, 划分为9类: 森林、灌丛、草本植被、荒漠、高山冻原与稀疏植被、沼泽与水生植被、农业植被、城市植被及无植被地段。关于《中国植被志》的卷册编排和“植被类型”划分, 首先按高级分类单位——植被型划分相应的“卷”; 在此框架下, 模糊“植被亚型”、“群系组”和“群系”的概念, 确定“植被类型” (Vegetation type), 并将其作为植被志各卷中的“册”。这样处理不仅保证了研编工作的可操作性, 也保持了同一卷册中特定植被类型的完整性。《中国植被志》编排体系中的“植被类型”的划分很重要, 它是指具有相同建群种及相同优势类群(如种、属)的植被组合, 但它不是严格意义上的植被分类单位。“植被类型”的划分遵循“优势类群及生活型的同一性, 生境条件的相对重要性, 植被特征及用途的差异性, 以及突出植被志的应用性”等原则。按该编排体系, 《中国植被志》将由48卷约110册组成。     

农杆菌介导5种中草药叶片瞬时表达的研究

农杆菌介导的瞬时基因表达因其操作简单、可重复性高和实验成本低而成为研究基因功能、生产活性蛋白的有效方法.该研究以非病毒型(载体Ⅰ)和病毒型二元载体(载体Ⅱ)及两种农杆菌(EHA105、LBA4404)为介导,通过叶片渗透法在5种中草药(甘草、黄芩、黄芪、大黄、板蓝根)叶片中进行报告基因GFP的瞬时表达,并对影响表达的因...     

常绿阔叶林内和林窗中栲树的种子萌发和幼苗生长

对浙江天童地区常绿阔叶林林窗和林内两种生境下人工播埋的栲树（Castanopsis fargesii）种子的萌发和当年幼苗的生长进行了研究。在林窗和林内两种生境的栲树种子（单粒重约0.5-0.6g）的萌发率没有明显的差异,分别为31.7±7.1％和33.3±2.l％,一年龄幼苗的平均株高在生长季末分别为 6.56±1.2cm和 5.88±1.09cm,两者有明显差异,而平均叶长、平均叶宽以及平均根长等指标没有差异;幼苗的生物量也没有明显差异。但一年龄幼苗在生长过程中,其生物量分配有所变化,在林窗条件下,幼苗逐渐将较多的生物量分配于根,而林内幼苗则逐渐将生物量较多地分配于叶,生物量的分配反映出幼苗在不同生境下的适应性特征。     

Increase in levels of microbiota recoverable from male and larval Myrmecia gulosa (Fabricius) (Hymenoptera: Formicidae) following segregation from worker ants

The segregation of laboratory maintained male and larval Myrmecia gulosa from workers resulted in increased levels of culturable microbiota. After 29 days, microbial levels recovered from segregated males and larvae were 27 and 126 times greater than from males and larvae not segregated from workers. These findings are consistent with the hypothesis that metapleural gland secretions, absent in larvae and males, are transferred from workers to larvae, and males contribute to the inhibition of cuticular microbiota.