Liver and uterine lipid metabolism: a comparative study

Zusammenfassung In-vitro-Inkubation von Leber-und Uterusgewebe der Ratte in Azetat-1-C¹⁴ ergab bei beiden Geweben Inkorporation gleicher Mengen von C¹⁴ pro mg Frischgewicht in Phospholipoide und in Estercholesterin. Die Leber synthetisiert wohl rascher Fettsäuren, vermag sie aber weniger schnell in die Triglyceride einzubauen als der Uterus.     

A comparative study of tryptophan metabolism in skins and livers of black and albino rats

Summary The skin of black rats contains less tryptophan than the skin of albino rats, possibly because the activity of tryptophan pyrrolase is higher. The opposite is found in liver, possibly because tryptophan pyrrolase activity is lower in the livers of black rats.Acknowledgments. The authors wish to thank Dr S.C. Bhattacharyya and Dr A. K. Barua, Bose Institute, for their interest in the work. The work was supported by the Council of Scientific and Industrial Research, New Delhi.     

The metabolism of hexamethylphosphoramide and hexamethylthiophosphoramide

Résumé L'hexaméthylphosphoramide (I), un agent antispermatogénique efficient pour rongeurs, est dégradé par une succession de déméthylations (I II III IV) pour inactifs metabolites. Le thio-analogue (V), à moins qu'il soit metabolisé (I), est inactif au cours d'un cheminement alternatif (V VI II).

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This work was supported by grants from the Ford Foundation and the Wellcome Trust.     

The comparative physiology of respiratory organs

Zusammenfassung Es wird in diesem Artikel versucht, die Evolution der Atemmechanismen in verschiedenen Entwicklungsrichtungen darzustellen und die Korrelation, welche zwischen Tiergröße und Leistung besteht, aufzuweisen.Die einfachsten Atemeinrichtungen lassen nur geringe Körpergröße und niedrigen Stoffwechsel zu.Kiemen, wie sie bei Wasserorganismen ausgebildet sind, können eine hohe Wirksamkeit entwickeln und erlauben eine gesteigerte Körpergröße.Der Übergang zum Luftleben, wie er in der Geschichte der Vertebraten wirklich vor sich gegangen ist, brachte eine ganz erhebliche Herabsetzung der respiratorischen Wirksamkeit des Kreislaufs mit sich, die erst bei den warmblütigen Säugetieren und Vögeln vollständig überwunden werden konnte.Die Vogellungen, die einen Luftstrom vor- und rückwärts durch die Luftkapillaren treiben, sind sogar wirksamer als diejenigen der Säugetiere.Die Atempigmente im Blute vieler Tierformen zeigen interessante Anpassungen an den Sauerstoff- und Kohlensäuredruck, dem die Tiere ausgesetzt sind.Tracheenatmung, die hauptsächlich durch Diffusion von Sauerstoff durch ein System starrer Röhren hervorgebracht wird, setzt der möglichen Größe der Tracheaten eine feste Grenze, aber sie läßt innerhalb dieser Grenze eine große Mannigfaltigkeit zu.

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Compiled fromA. Krogh. Comparative Physiology of Respiratory Mechanisms, Philadelphia 1940.     

The metabolism and function of sphingolipids and glycosphingolipids

Sphingolipids and glycosphingolipids are emerging as major players in many facets of cell physiology and pathophysiology. We now present an overview of sphingolipid biochemistry and physiology, followed by a brief presentation of recent advances in translational research related to sphingolipids. In discussing sphingolipid biochemistry, we focus on the structure of sphingolipids, and their biosynthetic pathways – the recent identification of most of the enzymes in this pathway has led to significant advances and better characterization of a number of the biosynthetic steps, and the relationship between them. We then discuss some roles of sphingolipids in cell physiology, particularly those of ceramide and sphingosine-1-phosphate, and mention current views about how these lipids act in signal transduction pathways. We end with a discussion of sphingolipids and glycosphingolipids in the etiology and pathology of a number of diseases, such as cancer, immunity, cystic fibrosis, emphysema, diabetes, and sepsis, areas in which sphingolipids are beginning to take a central position, even though many of the details remain to be elucidated. Received 13 February 2007; received after revision 19 April 2007; accepted 26 April 2007     

The metabolism of tri-alkyl phosphates

Résumé Les tri-alkyl phosphates (I) sont metabolisées par mono-dealkylation produisant des di-alkyl phosphates (II) et les S-alkyl cysteines (III) relatives chez le rat et la souri.

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This work was supported by grants from the Ford Foundation and the Wellcome Trust.     

Ultrasonification of ethylene glycol

Zusammenfassung In Gegenwart von Sauerstoff wird Äthylenglycol durch Ultraschall zu Peroxiden, Glycolaldehyd und/oder Glyoxal oxidiert.

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This work was supported in part by Grant No. F2-MH-10,498 of the Department of Health, Education and Welfare (USA).     

The metabolism of biphenyl byPseudomonas putida

Riassunto La degradazione del bifenile da parte diPs. putida inizia con la formazione di un diolo cui si attribuisce la struttura di 2,3-diidro-2,3-diossibifenile, in quanto, per disidratazione a caldo con acido cloridrico, si trasforma in 2-ossibifenile e tracce di 3-ossibifenile. Il diolo viene ulteriormente degradato ad acido benzoico. Le cellule diPs. putida cresciute su bifenile sono simultaneamente indotte ad ossidare al Warburg il bifenile e l'acido benzoico, non il 3,4-diossibifenile e l'acido fenilpiruvico. Le stesse cellule contengono una metapirocatecasi costitutiva.

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This work was supported by a grant of C.N.R. (Consiglio Nazionale delle Ricerche), for the International Biological Program.     

The comparative biology of neuromelanin and lipofuscin in the human brain

Neuromelanin and lipofuscin are two pigments produced within the human brain that, until recently, were considered inert cellular waste products of little interest to neuroscience. Recent research has increased our understanding of the nature and interactions of these pigments with their cellular environment and suggests that these pigments may, indeed, influence cellular function. The physical appearance and distribution of the pigments within the human brain differ, but both accumulate in the aging brain and the pigments share some structural features. Lipofuscin accumulation has been implicated in postmitotic cell aging, while neuromelanin is suggested to function as an iron-regulatory molecule with possible protective functions within the cells which produce this pigment. This review presents comparative aspects of the biology of neuromelanin and lipofuscin, as well as a discussion of their hypothesized functions in brain and their possible roles in aging and neurodegenerative disease.     

The glycerophosphoinositols: cellular metabolism and biological functions

The glycerophosphoinositols are cellular products of phospholipase A₂ and lysolipase activities on the membrane phosphoinositides. Their intracellular concentrations can vary upon oncogenic transformation, cell differentiation and hormonal stimulation. Specific glycerophosphodiester phosphodiesterases are involved in their catabolism, which, as with their formation, is under hormonal regulation. With their mechanisms of action including modulation of adenylyl cyclase, intracellular calcium levels, and Rho-GTPases, the glycerophosphoinositols have diverse effects in multiple cell types: induction of cell proliferation in thyroid cells; modulation of actin cytoskeleton organisation in fibroblasts; and reduction of the invasive potential of tumour cell lines. More recent investigations include their effects in inflammatory and immune responses. Indeed, the glycerophosphoinositols enhance cytokine-dependent chemotaxis in T-lymphocytes induced by SDF-1α-receptor activation, indicating roles for these compounds as modulators of T-cell signalling and T-cell responses.     

Mutagenic action of ethylene halogenhydrins

Zusammenfassung Eine stark mutagene Wirkung wird durch äthylenchlorhydrin, äthylenbromhydrin und äthylenjodhydrin aufKlebsiella pneumoniae ausgeübt.     

Morphological and biochemical effects of ethylene on Tulips

Summary Tulip bulbs treated with ethylene at various concentrations, at different stages of development and during various lengths of time, exhibited various morphological abnormalities: open bud, stamen blasting, abnormal number of floral parts, increased number of second-year bulbs. These morphological changes were paralleled by rapid variations in the contents of proteins and RNAs, and a slow, yet noticeable, increase of the DNA content of flower buds.     

The regulation of trehalose metabolism in insects

Trehalose is a non-reducing disaccharide comprising two glucose molecules. It is present in high concentration as the main haemolymph (blood) sugar in insects. The synthesis of trehalose in the fat body (an organ analogous in function to a combination of liver and adipose tissue in vertebrates) is stimulated by neuropeptides (hypertrehalosaemic hormones), released from the corpora cardiaca, a neurohaemal organ associated with the brain. The peptides cause a decrease in the content of fructose 2,6-bisphosphate in fat body cells. Fructose 2,6-bisphosphate, acting synergistically with AMP, is a potent activator of the glycolytic enzyme 6-phosphofructokinase-1 and a strong inhibitor of the gluconeogenic enzyme fructose 1,6-bisphosphatase. This indicates that fructose 2,6-bisphosphate is a key metabolic signal in the regulation of trehalose synthesis in insects. Trehalose is hydrolysed by trehalase (E.C. 3.2.1.28). The activity of this enzyme is regulated in flight muscle, but the mechanism by which this is achieved is unknown. Trehalase from locust, flight muscle is a glycoprotein bound to membranes of the microsomal fraction. The enzyme can be activated by detergents in vitro and by short flight intervals in vivo, which indicates that changes in the membrane environment modulate trehalase activity under physiological conditions.     

The blood vessels of cephalopods. A comparative morphological and functional survey

Summary The distinctive structural and functional features of the highly specialized blood vessel types (blood sinus, veins, aortae, arteries) of cephalopods are characterized in a comparative survey. Histochemical and physio-pharmacological results indicate a dual neuroregulation of the vessel wall but, however, show contrary effects of the neurotransmitter candidates, catecholamines, serotonin (5-HT) and ACh, on arteries and veins. The spontaneous pulsatile activity of the propulsive veins seems to be partly myogenic but also directly dependent on a dense cholinergic innervation of the sarcosome-rich obliquely striated myocytes.     

The metabolism of the proteins of the brain

Zusammenfassung Mit Hilfe von isotopem Lysin wurde der Austausch von freiem Lysin zwischen Blut und Gehirn, Leber und Muskel und die Umsatzrate der Eiweisskörper dieser Organe bestimmt.Im Zusammenhang mit den erhobenen Befunden wird die Funktion der Blut-Hirnschranke und die Erneuerung der freien Aminosäuren und der Proteine im Gehirn und in anderen Organen erörtert.

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Department of Biochemistry, College of Physicians and Surgeons, Columbia University; New York State Psychiatric Institute, New York.

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Special Fellow of the U. S. Public Health Service.     

The metabolism of methadone by cultured mammalian cells

Summary Rat hepatoma tissue culture cells and mouse leukemic cells were found to metabolize [1-³H] methadone to at least 2 unidentified radioactive compounds. These results suggest that cultured cells may be useful models for studying methadone metabolism by specific cell types.This study was supported by United States Public Health Service Research Grant No. MH 15622. The illustrations were prepared by Diane J. Kastelic.     

The action of tranquilizing drugs on brain metabolism

Zusammenfassung Die Tranquilizer Miltown (Meprobamat) und Benactyzin beeinflussen den Gehirnzellstoffwechselin vitro qualitativ wie Largactil, das heisst, sie hemmen die oxydative Phosphorylierung und gleichzeitig auch die ATPase-Aktivität. Demgegenüber hemmt das bloss über eine sedative Wirkung verfügende Captodiamin (Covatin) nur die oxydative Phosphorylierung und lässt die ATPase-Aktivität unbeeinflusst. Dies spricht dafür, dass zur Auslösung einer largactilartigen Wirkung beide oberen Hemmungsprozesse notwendig sind.