Evidence of a Cadmium-Thionein and the Glycine Cleavage System in Oxytricha granulifera

ABSTRACT. This work presents the further purification of a Cd-linking protein in Oxytricha granulifera by reverse-phase chromatography. This protein contains 25% cysteine and no aromatic amino acid. it may be considered as a chelatin with some similarity to metallothioneins. During the purification of another Cd-linking compound, we were able to demonstrate that the H protein precursor of glycine cleavage is present in Oxytricha. This is the first finding of the presence of this system in Protozoa.     

Enzyme Activity Pattern and Mitochondrio-cytoplasmic Relations in Protozoa. Comparative Study of Tetrahymena pyriformis, Allogromia laticollaris, and Labyrinthula coenocystis

SYNOPSIS. Enzyme activity patterns were determined in Tetrahymena pyriformis, Allogromia laticollaris , and Labyrinthula coenocystis. The activities of enzymes belonging to certain metabolic pathways (glycolysis, fatty acid oxidation, tricarboxylic acid cycle) had constant proportions in each species, whereas their absolute levels differed. The activities of intramitochondrial enzymes were compared with the mitochondrial to total cytoplasmic volume ratio. Despite the very different fine structure of the mitochondria in the 3 protozoa, there was good correlation between the activities of citric acid cycle enzymes and the mitochondrial volume.     

Potassium Fluxes in Excised Barley Roots

The method of the modified compartmental analysis for excisedroots has been adopted for measuring K⁺-fluxes and compartmentationin barley (Hordeum distichon) roots. Efflux of ⁴²K and ⁸⁶Rbindicated that more than two intracellular compartments wereinvolved in the tracer exchange; the ⁴²K data clearly showedthe components. On the basis of the efflux behaviour of theapical and more basal tissues of the roots, the three componentsof efflux were attributed to the cytoplasm of differentiated(fast) and meristematic tissues (intermediate) and to the vacuoles(slow exchange) of the roots. A model is proposed on the basisof which, the fluxes corresponding to the meristematic and differentiatedtissues of the root can be estimated. Additionally, fluxes ofthe differentiated root tissues were determined by using effluxdata obtained with root segments without apical tissues. Thedata obtained in both ways compare reasonably well and agreeto independent chemical measurements. Comparison of the ⁴²K and ⁸⁶Rb efflux data show strong discriminationof K^– in favour of Rb⁺ and indicate that ⁸⁶Rb is not suitableas a tracer for K⁺ in efflux measurements, at least with barleyroots.     

Ecological and Genetic Implications of Foliar Polymorphism inMetrosideros polymorphaGaud. (Myrtaceae) in a Habitat Matrix on Mauna Loa, Hawaii

Glabrous and pubescent foliar phenotypes ofMetrosideros polymorphaoccursympatrically on Mauna Loa, Hawaii. This coexistence has beensuggested, by earlier workers, to represent distinct genotypes,each of which produces progenies with a homogenous foliar phenotype.We re-examined the question of to what extent siblings fromthe same parents varied in phenotype when grown under the samecommon-garden conditions. Seeds were collected from parentaltrees in a matrix of two substrate ages (114–140 yrvs.approx.1200–3200 yr old) at five elevations from lowland (100m) to treeline (2470 m) on Mauna Loa. Seeds were sown and grownunder identical environmental conditions at 1200 m. In fieldparental populations, two forms converged into pubescent formswith decreasing rainfall (<2000 mm) on both substrates, andinto glabrous forms with increasing soil age where rainfallwas ample. The 4-yr old seedlings from pubescent parents invariablyexpressed both glabrous and pubescent phenotypes for all altitudesand for both substrate ages except for the young 1980-m site.The seedlings from glabrous parents tended to express only theglabrous phenotypes except for the young 1280-m site. Overall,all populations on the young lava flow (glabrous and pubescentindividuals combined if coexisting) could produce progeniesof both phenotypes except at 1980 m. Cuticle thickness on theadaxial lamina surface was positively correlated with the magnitudeof pubescence (P=0.05) among siblings from the same parents,ranging from a mean cuticle thickness of 6.0 µm for glabrousto 15.7 µm for the most pubescent individuals. Greatermagnitudes of pubescence were associated with more negativeosmotic potentials at turgor loss point, and with greater maximumCO₂assimilation rates at the point of light saturation. Thisphysiological and anatomical polymorphism, together with spatiallyand temporally varying selective forces, appears to result inelevationally and successionally patternedM. polymorphapopulationson the wet slope of Mauna Loa. Common-garden experiment; cuticle; foliar pubescence; Hawaii; Metrosideros polymorpha,natural selection; photosynthesis; polymorphism; primary succession; water potential     

Upper Cambrian stem-lineage crustaceans and their bearing upon the monophyletic origin of Crustacea and the position of Agnostus

Walossek, D. & Müller, K. J. 1990 10 15: Upper Cambrian stem-lineage crustaceans and their bearing upon the monophyletic origin of Crustacea and the position of Agnostus. Lethaia , Vol. 23, pp. 409–427. Oslo. ISSN 0024–1164.
Three new arthropods in uncompressed condition have been discovered in Upper Cambrian limestone nodules (Orsten) of Västergötland, Sweden. Together with Martinssonia elongafa Müller & Walossek, 1986, they are recognized as descendants of early offshoots from the stem-lineage of Crustacea. Their morphology provides new insights into the evolutionary path and progressive development of ground plan characteristics along the stem-lineage and gives further support for the monophyletic origin of Crustacea s. str., which embraces all taxa with extant derivatives. Structures of the ventral morphology shared between these stem-lineage crustaceans and Agnostus lead to the consideration of alternatives for the currently assumed position of agnostids. ▭ Crustacea. ontogeny, phosphatization. phylogeny, stem-lineage, Sweden, 3 D-preseroation, Trilobita     

DNA Damage and Repair in Stylonychia lemnae (Ciliata,Protozoa)1

ABSTRACT Irradiation with X rays, UV irradiation after incorporation of bromodeoxyuridine (BU) into the DNA, and cis-platinum (cis-Pt) treatment each cause the loss of micronuclei of Stylonychia lemnae while the macronuclei are not severely affected. The abilities of both nuclei to repair DNA were investigated. Unscheduled DNA synthesis could not be demonstrated after X-ray irradiation, but it was found after treatment with BU/UV and cis-Pt in macro- and micronuclei. The extent of the repair process in the micro- and macronuclei was alike, as indicated by grain counts of [6-³H]thymidine-treated cells. One reason for the different sensitivity of both nuclei to DNA-damaging treatment may be the different number of gene copies in the macro- and micronuclei.     

PERNICIÖSE EPÖKIE VON PLACUNOPSIS AUF CERATITES

An adult Ceratites semipartitus encrusted by epifaunal Placunopsis ostracina is described. The epizoans are orientated in relation to the slope of the substratum and according to their time of attachment to the ammonoid shell. Geometrical analysis of the orientation leads to the following conclusions: (1) During and after the growth of the last whorl, several, probably 4, swarms of larvae of Placunopsis settled upon the Ceratites specimen. (2) The dead body was for some time kept upright, the living chamber showing upwards. During this time, larvae of Placunopsis became attached again. (3) The ammonoid shell was then laid down, its left flank in contact with the sediment. In this position it was for the last time settled upon by Placunopsis which died whilst juvenile.
Provided that the phases of attachment corresponded to annual spawning periods of Placunopsis , the last whorl of the Ceratites was formed with decreasing velocity of growth within about 4 years.
Placunopsis became attached with its right valve, the posterior end of the body showing upwards, and the direction of growth being declined from the vertical by 65°. Placunopsis either preferred to settle within a distinct zone of the living chamber of the ammonoid close to the lowermost part of the shell or was able to grow up here only. Ceratites semipartitus was therefore probably nectonic.
Both the host and the epizoan were influenced to their disadvantage by their fatal partnership. A relationship of this kind therefore should not be called a symbiosis.