Flavonoid profiles of certain species ofRhynchosia of the family Leguminosae (Fabaceae)

Summary A survey of seventy naturally occurring populations ofRhynchosia representing seven species of different subgenera revealed the occurrence of C-glycosides, O-glycosides, prenylated flavonoids and aglycones.Rhynchosia albiflora (R. cyanosperma) differs in gross morphological features and seed coat color and in its flavonoid composition from the other representative species ofRhynchosia.Acknowledgments. P. Ramachandraiah is grateful to U.G.C., New Delhi, for financial assistance.     

Alteration of cell shape in the early chick embryo mesoderm by neuraminidase

Summary Living chick embryo mesoderm cells (stages 3 to 5) were exposed to neuraminidase. The mesoderm cells changed shape losing their long thin processes and become like primitive streak cells, with short flat processes. Ruthenium red staining of such treated embryos shows that the surface coat on the mesoderm cells is reduced in thickness. These results show that cell shape in the chick embryo mesoderm is at least partly determined by the thickness and the composition of the surface coat.Acknowledgment. It is a pleasure to thank Professor F. Beck for the facilities of the Department of Anatomy, University of Leicester, and Mr. G. L. C. McTurk of the University of Leicester Scanning Electron Microscope Unit for operating the ISI 60 SEM. Mr Jeff Smith and Mrs Doris Duncan gave us valuable technical assistance and Dr. A. J. Rowe kindly allowed us to use the facilities of the Electron Microscope Unit, University of Leicester School of Biological Sciences, in specimen preparation.     

Flavonol glycosides and seed coat structure in certain species ofEpilobium — A correlation?

Summary In a survey of 239 populations ofEpilobium representing 17 taxa the following flavonol glycosides were found: myricetin 3-O-arabinoside; 3-O-glucoside; 3-O-rhamnoside; quercetin 3-O-arabinoside; 3-O-glucoside; 3-O-diglucoside; 3-O-rhamnoside; kaempferol 3-O-glucoside; and 3-O-rhamnoside. A correlation appears to exist between seed coat sculpturing as determined in a previous study using SEM techniques, and the flavonoid profiles.Acknowledgments. This study was supported in part by NSERC of Canada and The Boreal Institute for Northern Studies.     

Assembly and genetics of spore protective structures

The sporulation program in Bacillus subtilis ends in the formation of a highly resistant endospore that can withstand extremes of heat, mechanical disruption, ultraviolet irradiation, lytic enzymes and chemical attack. These properties are attributed mainly to the unique structure of spore coat and cortex, as well as to the physical state of the spore cytoplasm. The outermost layer of the spore, called the coat, has two morphologically distinct sublayers: an electron-dense outer coat and an electron-translucent inner coat. The coat is composed of more than 2 dozen proteins of varying size. Many coat genes and coat proteins have been isolated and characterized in detail, and studies of these have identified proteins with important roles in coat assembly, resistance and spore germination. We describe here characteristics of the coat proteins and propose a model for coat assembly based on recent work.     

Membrane traffic in the secretory pathway

Vesicular transport is the basic communication mechanism between different compartments in a cell and with the environment. In this review I discuss the principles of vesicle generation and consumption with particular emphasis on the different types of coat proteins and the timing of the shedding of the coat proteins from transport containers. In recent years it has become clear that there are more coat complexes than the classical COPI, COPII and clathrin coats. These additional coats may generate vesicles that transport cargo in a temporally and/or spatially controlled manner. Work over the last years suggests that GTP hydrolysis occurs early during vesicle biogenesis, destabilizing the coat perhaps before fission of the vesicle from the donor membrane occurs. Recent findings imply, however, that tethers at the receiving compartment specifically detect the coat on vesicle. (Part of a Multi-author Review)     

Membrane traffic in the secretory pathway

Vesicular transport is the basic communication mechanism between different compartments in a cell and with the environment. In this review I discuss the principles of vesicle generation and consumption with particular emphasis on the different types of coat proteins and the timing of the shedding of the coat proteins from transport containers. In recent years it has become clear that there are more coat complexes than the classical COPI, COPII and clathrin coats. These additional coats may generate vesicles that transport cargo in a temporally and/or spatially controlled manner. Work over the last years suggests that GTP hydrolysis occurs early during vesicle biogenesis, destabilizing the coat perhaps before fission of the vesicle from the donor membrane occurs. Recent findings imply, however, that tethers at the receiving compartment specifically detect the coat on vesicle. (Part of a Multi-author Review)     

Histochemistry of the lumenal cell surfaces of the mucosa of the oviducts and the uterus of the rat. Changes in prepuberty, estrous cycle, castration, hormone replacement and pseudopregnancy.

The lumenal surface coat of the rat oviducts and uterine horns have been histochemically characterized at prepuberty, estrous cycle, castration, hormone replacement and pseudopregnancy. Under the EM, the coat was made up of filamentous and globular structures. Histochemical variations suggested that coat components are under endocrine control.     

化感活性物质影响种子萌发作用机理的研究进展

化感作用由于其独特的生物学特性而受到广泛关注,并逐渐成为近年来的研究热点。然而目前多数的化感作用研究关注于化感物质对幼苗生长的影响以及化感物质的分离、鉴定、提纯,而对化感物质影响植物种子萌发的作用机理缺乏足够的重视。本文主要论述了化感作用的概念、发展以及化感物质降低种子萌发率、改变激素平衡、破坏生物膜结构、影响种子呼吸代谢等一系列生理活动的作用机理。最后对今后化感作用的研究重点进行展望,强调应着重进行化感物质作用机理的精确研究,从分子、基因水平进行探讨。     

The cellular functions of clathrin

Membranes and proteins are moved around the cell in small vesicles. A protein coat aids the budding of such vesicles from donor membranes. The major type of coat used by the cell is composed of clathrin, a three-legged protein that can form lattice-like coats on membranes destined for trafficking. In this review, I outline what we know about clathrin and discuss some recent advances in understanding the basic biology of this fascinating molecule, which include building a molecular model of a clathrin lattice and discovery of a new function for clathrin that occurs during mitosis. Received 12 December 2005; received after revision 21 March 2006; accepted 29 March 2006     

Membrane traffic in the secretory pathway

Cholesterol, certain lipids, membrane-bound and soluble proteins, as well as viruses that are synthesized in the endoplasmic reticulum (ER), reach the plasma membrane (PM) via non-classical pathway(s) that remain poorly understood. Typical for this transport is (i) its insensitivity to brefeldin A (BFA), which dissociates selected coat complexes from membranes, resulting in the disassembly of the Golgi apparatus; (ii) its rapid kinetics as compared to the classical secretory pathway; and (iii) its role in the trafficking of lipid raft components. Based on results showing that the intermediate compartment (IC) at the ER-Golgi boundary constitutes a stable tubular network that maintains its dynamics in the presence of BFA, we propose that two bidirectional Golgi-bypass pathways to the PM exist, a direct route from early IC elements, and another, reminiscent of the yeast secretory pathway, from late IC elements via the endosomal system. These pathways have implications for the organization of the secretory processes in different cell types.     

Influence of the enteric surface coat on the unidirectional flux of acetamide across the wall of rat small intestine

In vivo treatment of the jejunal mucosa with glycosidic enzymes seems to remove the enteric surface coat of the enterocyte. As a consequence, the mucosa-to-serosa unidirectional flux of acetamide increases remarkably. The glycocalyx probably represents a barrier to the diffusion of small hydrosoluble solutes.     

Trans-Golgi network sorting

The trans-Golgi network (TGN) is a major secretory pathway sorting station that directs newly synthesized proteins to different subcellular destinations. The TGN also receives extracellular materials and recycled molecules from endocytic compartments. In this review, we summarize recent progress on understanding TGN structure and the dynamics of trafficking to and from this compartment. Protein sorting into different transport vesicles requires specific interactions between sorting motifs on the cargo molecules and vesicle coat components that recognize these motifs. Current understanding of the various targeting signals and vesicle coat components that are involved in TGN sorting are discussed, as well as the molecules that participate in retrieval to this compartment in both yeast and mammalian cells. Besides proteins, lipids and lipid-modifying enzymes also participate actively in the formation of secretory vesicles. The possible mechanisms of action of these lipid hydrolases and lipid kinases are discussed. Finally, we summarize the fundamentally different apical and basolateral cell surface delivery mechanisms and the current facts and hypotheses on protein sorting from the TGN into the regulated secretory pathway in neuroendocrine cells. Received 2 November 2000; received after revision 19 February 2001; accepted 19 February 2001     

Abhängigkeit der Leukozytenwanderung und ihrer Steigerung durch Proteuslipo-polysaccharide von der Glucosekonzentration des Milieus

Summary The migration of leucocytes from the buffy coat is influenced by the glucose concentration in the medium, stimulation of migration results from concentrations of glucose up to 2%.. Higher concentrations of glucose up to 8%. have no effect. The stimulating effect of a constant concentration PLPS increases considerably over the whole range of glucose concentrations up to 8%.. Optimal stimulation by PLPS depends therefore on the glucose concentration.     

Degeneration of adrenergic axons in the longitudinal muscle coat of the rat duodenum following treatment with 6-hydroxydopamine.

Following systemic treatment with 6-OHDA, electron microscopy of adult rat duodenum showed degenerating adrenergic axons in the longitudinal muscle coat making neuromuscular relationships with gaps of varied widths.     

Untersuchungen über die Nikotinbildung des Tabaks

Summary During germination the tobacco seedling produces nicotine from proteins accumulated in the seed. Later on the nicotine formation of the growing tobacco plant is dependent on the protein synthesis in its root. The comparison of theprotein production by the tobacco root with thenicotine content of the whole plant shows an interesting parallelism.     

Preparative separation of nucleated cells from human bone marrow.

A comparison has been made between the separation of nucleated cells from human bone marrow aspirates by high mol. wt polymers and the buffy coat techniques.     

The glycocalyx of the epithelial cells of the colon, observed in normal and ulcerous colitic conditions.

Biopsies of subjects affected by ulcerous colitis were stained with ruthenium Red. Alterations of the cellular coat and glycocalyx of the epithelial cells of the colon were identified.     

Measurement of the position and intensity of chromosomal denaturation bands by an automatic system]

The band density profile of a marked chromosome was obtained using a photodiode collector combined with a minicalculator, working with an ordinary photographic document. The measurement was carried out over 10 to 20 300-point lines oriented longitudinally along the chromosome. The profile obtained corresponds to the sum of the values of each of these lines. The proposed systems's originality resides in its ability to determine the position and intensity of a band over the entire thickness of the chromosome.     

Localization of vitelline-coat lysin purified from testis of a top shell,Turbo cornutus

Summary The vitelline-coat lysin purified from the testis ofTurbo cornutus was found, by an immunofluorescence technique, to be located in the acrosome of the sperm, which suggested that the lysin reacts with the vitelline-coat in an early phase of fertilization to allow the sperm to penetrate through the coat.We are grateful to Professor M. Akino (Tokyo Metropolitan University) for his helpful advice.     

Ultrastructure of epiphyseal cartilage after extraction on thin sections of "Epon" of proteoglycans by calcium chloride]

Dissociative methods are commonly used to extract proteoglycans. With a 2 M CaCl2 solution these components can be also extracted from thin sections of fixed, "Epon" included material. Secretory granules of the chondrocytes, granular components of extracellular matrix as matrix vesicles lost their electron density. Glycoproteins of the cell coat as non collagenous glycoproteins disappear. The method seems to be valuable for extracting proteoglycans from thin sections prepared for electron microscope investigations.