Secreted oleanolic acid on the cuticleOlea europaea (Oleaceae); a chemical barrier to fungal attack

Summary The leaf of the bitter oliveOlea europaea (Oleaceae) is heavily coated by almost pure oleanolic acid, which forms part of a multichemical defense against fungal attack.We thank Mr K. A. Hoelmer for taking the electron micrographs and also Professor T. Kamikawa for NMR measurements.     

Palaeogene fossil <Emphasis Type="Italic">Populus</Emphasis> leaves from Lanzhou Basin and their palaeoclimatic significance

An angiosperm compression flora is found in Palaeogene from Lanzhou Basin and the cuticular analysis of Populus davidiana Dode in the flora is carefully made. Furthermore, the fossil cuticles are compared with the epidermal structures of extant Populus leaves growing in different environments, i.e. moist, semimoist, and semiarid to arid climatic regions. The present experiments indicate that mature leaves of P. davidiana show leaf size from big to small, leaf cuticles from thick to thin and anticlinal walls of epidermal cells from faintness to clarity along with the increase of lattudes of the plant distributions, the climatic variation from moist to arid, the annual precipitation from more to less and the annual mean temperature from high to low. The fossil P. davidiana differs from the specimens collected from Shandan in semiarid to arid climatic regions but closely resembles the Wushan leaves in a semi-moist climatic area in a lot of features. In a word, the new research may reflect that the flora lives in a semi-moist climatic environment. The present discovery of compression of Paleogene Populus davidiana is of great significance to studying vegetation types, climatic and environmental changes during the primal uplifting of the Qinghai-Tibet Plateau.     

华南地区湖南省芙蓉统(上寒武统)的古蠕虫骨片:个体生长对表皮骨片形态的影响

报道最近发现的华南地区湖南省芙蓉统(上寒武统)三维保存的古蠕虫骨片碎片。描述两个新的形态属和两个新的形态种: Hunanoscolex campus 新属新种和Ornatoscolex hunanensis新属新种。大部分标本属于幼体阶段。Hunanoscolex campus体节宽度的巨大差异显示其处于生长发育阶段, 因此可以对个体生长对表皮骨片形态的影响进行研究。虫体生长主要依靠增加单个体节中骨片的数量。位于同一排中的大骨板排列变得疏松。新增加的小骨板和微骨板大小和纹饰基本不变, 但大骨板的纹饰可能存在变化。这些观察结果有助于更好地理解古蠕虫骨片的种内差异, 从而可能提高形态种属分类的准确性。     

Sclerotization of mosquito cuticle

Summary The mode of sclerotization ofAedes aegypti pupal and adult cuticle was examined by employing biochemical and radioactive techniques. During larval-pupal metamorphosis, tyrosine is converted to tanning precursors and is incorporated into aryl-amino adducts and -crosslinks. The major hydrolysis product of -crosslinks in pupal cases is identified to be arterenone. Examination of tanning modes in five different mosquito species shows that the ratio of quinone to -sclerotization not only differs within the life stages of the insects, but also differs between species.Study supported by N.I.H. Grant ROI-AI-14753.     

MIXTA/MIXTA-like基因特征及其对植物表皮细胞分化的调控

植物表皮细胞是植物最外层直接与环境相互作用的细胞,依据其不同功能,分化形成多种具有防卫功能的特化细胞结构,在植物防御、减少蒸腾、授粉媒介吸引、种子散布、次生代谢产物合成与贮存等方面起着重要作用。研究发现MIXTA/MIXTA-like是多种植物表皮细胞分化的关键调控因子。在不同植物中,MIXTA/MIXTA-like作用部位(主要集中在花瓣、叶片、胚珠和子房)和调节方式不同,但最终都是通过调控表皮细胞分化发挥作用。MIXTA/MIXTA-like在表皮毛的形成、角质层生物合成、锥形表皮细胞的分化过程中起着重要的调节作用,其中植物表皮毛发育是一个研究热点。植物表皮毛有多种不同的功能:如叶片被毛是植物抵御取食昆虫的重要表型特征;法国梧桐、杨树、柳树飞絮都是种子成熟过程中表皮毛发育的结果;而黄花蒿中,青蒿素主要在腺毛中合成和储存。因此,开展植物表皮毛发育和调控机制研究具有重要意义。笔者梳理了MIXTA/MIXTA-like基因的特征及其在不同植物表皮细胞分化过程中的生物学功能,阐述了木本植物表皮毛发育调控的分子机制,为加速林木表皮毛发育相关性状的新品种培育提供借鉴。     

Ultrastructure of the prezoeal cuticle and integument of the first zoea of Pagurus brachiomastus (Thallwitz) (Anomura,Paguridae) just after hatching

Transverse sections of the prezoea stage of Pagurus brachiomastus (Thallwitz) were made to determine the fine structure of the prezoeal cuticle and the exoskeleton of the first zoea, by using transmission electron microscopy. The thin cuticle covering the newly hatched prezoea is 15–17 nm thick, which is approximately 24 times thinner than the zoeal cuticle. High resolution revealed a trilaminar structure of the prezoeal cuticle, which is composed of an outer layer, approximately 4·4 nm thick, a mid lighter layer, approximately 3·5 nm thick, and an inner layer, approximately 7·7 nm thick. During the prezoeal stage, the inner zoeal exoskeleton consists of an epicuticle and an exocuticle, measuring approximately 0·36 μm thick. At this stage, there were no indications of the formation of endocuticle.     

古植物组合与煤岩类型关系的研究

本文研究了成煤物质－植物与成煤结果－煤（煤岩类型）两者之间的关系，认为煤岩类型与植物组合有关．     

5种鼠类针毛结构的扫描电镜分析

通过光镜和扫描电镜对社鼠、白腹巨鼠、黑线姬鼠、青毛鼠和黄胸鼠背部针毛的形态结构进行了对比研究,其针毛上的鳞片类型可分为波状、指状、多鳞状、杂波状和锯齿杯状5种.单因素方差分析和多重比较表明,各鳞片类型在不同鼠种中的比例差异显著,具有种的特异性,可以作为鼠类分类的参考指标.     

Chitin in the epidermal cuticle of a vertebrate (Paralipophrys trigloides,Blenniidae, Teleostei)

Lectin binding, endo-chitinase binding and enzymatic degradation studies show that the epidermal cuticle of the bony fishParalipophrys trigloides (Blenniidae) is chitinous. This is the first evidence that a vertebrate species possesses a chitinous tissue. Recently aXenopus gene has been identified which has significant sequence similarity to the catalytic domain of yeast chitin synthase III, a chitin producing enzyme^1,2. Taken together these two findings imply that chitin synthesis capability may be a basic vertebrate feature.