Relationship between chlorophyll a content and protein content of invertebrate symbioses with algae or chloroplasts

Summary The chlorophyll a and protein contents of invertebrates containing autotrophic symbionts are indices of symbiont and host biomass, respectively, and the chlorophyll a content per unit protein is a good measure of symbiont: host ratio. For three different associations, the chlorophyll a content per unit protein is 0.01–0.02 g g^–1.The hydra andE. viridis were provided by M. H. Christopher and J. R. Turner. I thank Professor D. C. Smith, Dr J. B. Searle and Dr T. A. V. Rees for the valuable comments on drafts of this paper. This work was supported by research grants from S.E.R.C.     

Regional variation in copper content of arterial wall

Résumé La teneur en cuivre dans l'aorte et les artères pulmonaire, rénale, illiaque et carotide a été déterminée. Une corrélation inverse entre le degré d'athérosclérose et celui du cuivre a été observée. La cause de ce phénomène reste à ètre établie.     

The morphology of cytoplasts and karyoplasts produced by cytochalasin D

Summary The denucleation of L cells and human lymphocytes in suspension was carried out by incubation with cytochalasin D25 and 50 g/ml and with ultracentrifugation over a discontinuous Ficoll gradient. Ultrastructural examination of the separate layers confirmed the presence of the anucleate cytoplasm (cytoplasts) with intact membrane and the separated nuclei (karyoplasts).This work was supported by a grant from the National Cancer Institute of Canada.     

Correlation betweenpara-phenylene diamine oxidase activity and the copper content of rat serum

Résumé Il y a une corrélation très forte entre l'activité de lapara-phénylène diamine oxydase du sérum sanguin du rat et de son taux en cuivre.     

The morphology of cytoplasts and karyoplasts produced by cytochalasin D.

The denucleation of L cells and human lymphocytes in suspension was carried out by incubation with cytochalasin D25 and 50 microgram/ml and with ultracentrifugation over a discontinuous Ficoll gradient. Ultrastructural examination of the separate layers confirmed the presence of the anucleate cytoplasm (cytoplasts) with intact membrane and the separated nuclei (karyoplasts).     

Effect of feeding psoralen on the copper content of different organs in albino rats

Zusammenfassung Psoralenfütterung von Ratten bewirkt eine Vermehrung des Kupfergehaltes in der Milz und eine Verminderung in der Leber. In der Haut sind die Werte nicht einheitlich.     

On the balloon-formation of isolated chloroplasts and grana

Zusammenfassung Isolierte Chloroplasten von Spinat und Nitella in Aqua dest. zeigen infolge Membranerweiterung 2 verschiedene Typen ballonförmiger Chloroplasten. Die Erscheinungen bei Grana sind ähnlich. Es wird die osmotische Natur des ballonförmigen Chloroplasten beschrieben.     

The genetic code in mitochondria and chloroplasts

The universal genetic code is used without changes in chloroplasts and in mitochondria of green plants. Non-plant mitochondria use codes that include changes from the universal code. Chloroplasts use 31 anticodons in translating the code; a number smaller than that used by bacteria, because chloroplasts have eliminated 10 CNN anticodons that are found in bacteria. Green plant mitochondria (mt) obtain some tRNAs from the cytosol, and genes for some other tRNAs have been acquired from chloroplast DNA. The code in non-plant mt differs from the universal code in the following usages found in various organisms: UGA for Trp, AUA for Met, AGR for Ser and stop, AAA for Asn, CUN for Thr, and possibly UAA for Tyr. CGN codons are not used by Torulopsis yeast mt. Non-plant mt, e.g. in vertebrates, may use a minimum of 22 anticodons for complete translation of mRNA sequences. The following possible causes are regarded as contributing to changes in the non-plant mt: directional mutation pressure, genomic economization, changes in charging specificity of tRNAs, loss of release factor RF2, changes in RF1, changes in anticodons, loss of lysidine-forming enzyme system, and disappearance of codons from coding sequences.     

Lipoxygenase activity of wheat seeding chloroplasts]

Chloroplasts have been isolated from Wheat shoots by density gradient centrifugation. When added to a linoleic acid and Tween 20 suspension these chloroplasts induce an oxygen consumption. The hydroperoxides synthesized from linoleic and oxygen have been characterized by spectrophotometry and thin layer chromatography.     

Photosynthesis by isolated chloroplasts of Sorghum vulgare.

The ambiguous location of photosynthetic carboxylases of mesophyll and bundle sheath chloroplasts of sorghum was investigated after successful homogeneous preparation. The phosphoenol pyruvate carboxylase was found as a particulate enzyme in the mesophyll cell chloroplasts and ribulose 1,5-biphosphate carboxylase in the stroma of the bundle sheath cell chloroplasts. Extensive characterization was carried out on these 2 enzymes for better understanding of the enzyme action.     

The dependence of photosynthesis on the arrangement of chloroplasts

Zusammenfassung Der Zusammenhang zwischen Chloroplastenstellung und Photosynthese wird durch gleichzeitige Messung des Gasaustausches und Registrierung der Chloroplastenstellung untersucht. Die Bewegungen der Chloroplasten in Dunkelheit haben keinen Einfluss auf die Atmungsintensität. Die Bewegungen, welche im schwachen Licht zur Vergrösserung der Assimilationsfläche führen (Bewegung der Chloroplasten von Profilstellung, hervorgerufen durch Dunkelheit oder starkes Licht, zur Flächenstellung), bringen eine Steigerung der Assimilationsintensität. Dagegen schreitet die Photosynthese im starken Licht mit unveränderter Intensität fort. Sie ist unabhängig von den gleichzeitig verlaufenden Chloroplastenverlagerungen. Die Ergebnisse werden auf Grund des Minimumgesetzes diskutiert.     

Kinetin/Auxin ratio and development of chloroplasts in tissue cultures ofDaucus carota

Riassunto Nell'intento di stabilire i fattori responsabili del differenziamento dei cloroplasti in culture di tessuto diDaucus carota, sono stati eseguiti esperimenti al fine di scegliere tra le 3 ipotesi possibili: la chinetina stimola la formazione dei cloroplasti; le auxine inibiscono la formazione dei cloroplasti; il differenziamento dei cloroplasti dipende dal rapporto chinetina/auxina, indipendentemente dalla quantità assoluta dei 2 ormoni. Sidimostra che quest'ultima ipotesi é corretta.     

Electron microscopic observation of the balloon-formation of isolated spinach chloroplasts

Zusammenfassung Die Ballonbildung isolierter Spinatchloroplasten wurde elektronenoptisch untersucht.

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The authors wish to thank Dr. Y.Kishida for his helpful advice in electron microscopy.     

Manganese prolongation of pentobarbital hypnosis in the male rat

Summary Following manganese treatment, pentobarbital hypnosis was prolonged in male rats. The maximal effect occurred from 1 to 3 days following manganese treatment and the threshold dose was found to be 3 mg Mn⁺⁺/kg (i.p.).Acknowledgments. This work was supported by NIEHS Research Grant ES-02425. These data were submitted as part of a Ph.D. thesis to Purdue University, West Lafayette, Indiana, by M.J. Deimling.