Effects of canavanine on IAA- and fusicoccin-stimulated cell enlargement, proton extrusion and potassium uptake in maize coleoptiles

In maize coleoptiles (Zea mays F₁ XL 640A, cv. Dekalb) canavanine and cycloheximide strongly and simultaneously inhibit cell elongation, H⁺ extrusion and K⁺ uptake, induced by IAA. They inhibit also, although to a much lesser degree, the same phenomena induced by fusicoccin. Cycloheximide severely depresses the incorporation of leucine into proteins, while canavanine leaves leucine incorporation almost unchanged. The data confirm that elongation, H⁺ extrusion and K⁺ uptake can be regarded as correlated processes; they also support the view that normal protein synthesis is essential for IAA-induced growth, while this requirement is only partial in growth stimulated by fusicoccin.     

A multiplex set of microsatellite markers for the scarlet rosefinch (Carpodacus erythrinus)

Cardueline finches have become important models in studies of sexual selection and evolution of carotenoid‐based ornamentation. Here, we describe eight new polymorphic microsatellites isolated from the Scarlet rosefinch (Carpodacus erythrinus) and four from the House finch (Carpodacus mexicanus). Together with the cross‐species amplification of additional loci, originally published for two species of songbirds, we optimized a multiplex panel for C. erythrinus allowing genotyping of 22 polymorphic loci. Number of alleles and heterozygosity per locus in a sample of 34 individuals ranged from three to 38 and from 0.27 to 0.94, respectively.     

Isolation and characterization of microsatellite loci in the woolly mouse opossum,Micoureus paraguayanus (Marsupialia: Didelphimorphia)

Five microsatellite loci were isolated and characterized within the woolly mouse opossum (Micoureus paraguayanus), a Neotropical marsupial, using an enrichment cloning procedure. Between four and seven alleles were detected per locus, with expected heterozygosity ranging from 0.358 to 0.560. These microsatellites should provide useful markers in a variety of genetic analyses to examine parentage, inbreeding, population structure and population dynamics in fragmented forest habitats.     

Leptomonas ciliatorum n. sp. (Kinetoplastida,Trypanosomatidae) in the Macronucleus of a Hypotrichous Ciliate1

A leptomonad flagellate found in the macronucleus of the hypotrichous ciliate Paraholosticha sterkii carries out its whole life cycle there. The ciliates can divide, encyst, and excyst even when parasitized, and the flagellates are maintained throughout. Parasite-free ciliates may be rapidly infected. The light- and electron-microscopic structure of the flagellate resembles that of other leptomonads.     

THE GREENING OF ETIOLATED BEAN LEAVES AND THE DEVELOPMENT OF CHLOROPLAST FINE STRUCTURE IN ABSENCE OF PHOTOSYNTHESIS

CMU inhibits oxygen evolution in greening etiolated bean leaves.In the presence of this compound chlorophyll content is reducedand fine structure development of the chloroplasts is markedlyaffected. The number of grana per chloroplast is reduced butthe grana are larger and contain more thylakoids than the granain chloroplasts of the greening control leaves. Sucrose reversesthe effect of CMU on pigment content and fine structure developmentof chloroplasts. (Received September 14, 1965; )     

A 3d-fem Simulation of Highest Stress Lines in Mandible Fractures by Elastic Impact

Abstract

In this article, the more usual mandible fracture areas are located by identifying the highest stress lines using a three-dimensional (tetrahedral) finite element method. By taking into account the temporomandibular contact and the inertia effects, the mathematical model is considered to be a dynamic Signorini's problem, that is, a dynamic variational inequality which is discretized in time following Newmark's method. So, in each time step a stationary variational inequality is solved by a penalty-duality algorithm. Finally, some numerical results obtained by simulating the more usual fractures in the human mandible are presented and compared with clinical experimental information.     

Endodermis-like Sheaths in the Submerged Freshwater MacrophyteRanunculus trichophyllusChaix

Light, fluorescence and electron microscopical analysis of therooted freshwater plantRanunculus trichophyllusrevealed a peculiaranatomical feature. In addition to the true endodermis encirclingthe root stele, endodermis-like sheaths occurred around eachvascular bundle of the leaf segments and of the eustelic stemwith its large central cavity, which assumed an anatomical featureresembling that of some pteridophyte stems. These impermeablesheaths, whose cells differentiate suberized walls, can playa major role in hampering the apoplastic leakage of the pressurizedwater solution which flows throughout the plant in xylem vesselsand contains the mineral nutrients taken up by the roots fromthe sediment. Moreover, these sheaths can function in preventingflooding of the aerenchymatic cavities of the submerged organs.In this way the endodermis-like sheaths preserve the correctcirculation of gas and nutrient solution through the entireorganism and assume great significance as a structural mechanismevolved by this species to survive and grow underwater.Copyright1999 Annals of Botany Company. Ranunculus trichophyllus,freshwater macrophyte, submerged angiosperm, anatomy, endodermis, endodermis-like sheaths, light microscopy, fluorescence microscopy.