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At least 325 records · Page 18Linked to original sources
PubMed1981

BBM-928, a new antitumor antibiotic complex. III. Structure determination of BBM-928 A, B and C.

Structures of antitumor antibiotics BBM-928 A, B and C have been determined. They are cyclic decadepsipeptides containing 3-hydroxy-6-methoxyquinaldic acid as a chromophore. Two amino acids, not found in nature, L-beta-hydroxyl-N-methylvaline and trans-(3S,4S)-4-hydroxy-2,3,4,5-tetrahydropyridazine-3-carboxylic acid, were identified as structural constituents of the antibiotic. In gross structure, BBM-928 resembles the echinomycin group of antibiotics which are cyclic octadepsipeptides having a quinoxaline chromophore, but BBM-928 differs from the latter group by virtue of the lack of a sulfur-containing cross linkage.

Antibiotics, Antineoplastic↗
PubMed1983

Bu-2470, a new peptide antibiotic complex. II. Structure determination of Bu-2470 A, B1, B2a and B2b.

The structures of Bu-2470 A, B1, B2a, and B2b have been determined. Bu-2470 A is a simple octapeptide having no fatty acid moiety, while Bu-2470 B1, B2a and B2b are octapeptides that have been acylated with a beta-hydroxy C11 or C10 fatty acid. The octapeptide structure of Bu-2470 components was found identical with that of octapeptin C1, hence generic names of octapeptin C0, C2, C3 and C4 are proposed for Bu-2470 A, B1, B2a and B2b, respectively.

Amidohydrolases↗
PubMed1992

On the fine structure and complex carbohydrate cytochemistry of the rabbit parotid gland.

The parotid gland of the rabbit, a lagomorph species, was studied by ultrastructural techniques and carbohydrate ultracytochemical stainings. The rabbit parotid gland is a peculiar mixed gland consisting of serous and mucous secretory cells due to their histochemical properties supported by biochemical findings. Acinar cells exhibit heterogeneous features of secretory granules with different electrondensity and occasional presence of subunits. Intercalated duct cells show nuclei with deep indentation and apical granules partly similar to acinar secretory products. Striated ducts are characterized by three different cell populations, namely "light cells" with small secretory granules, "dark cells" rich of scattered mitochondria and typical striated cells. The presence of differentiated cell types within striated duct segments lends credence to the idea that, in addition to the role in electrolyte transport, some ductal cells may be involved in secretion and/or absorption of glycosylated products.

Animals↗
PubMed1990

[Functional morphology of the kidney. A review of the histophysiology of the kidney glomerulus, the nephrons and the collecting tubule system].

The kidney is a composite organ, the specific activities of which are attributable to the peculiar construction of the individual components of the glomerula, nephrons and collecting tubules. This comprehensive review will address the essential physiological mechanisms of urine formation, such as filtration, secretion, reabsorption and concentration, and correlate these functions to morphological structures where possible. The complex structure of the renal glomerulus as the basis for the formation of primary urine (blood-urine barrier) will be documented on the basis of electron micrographs. In addition to this, the ultrastructure of the epithelium in the various tubular segments and collecting tubules will be discussed from a histophysiological stand-point, including its significance in the excretion of waste substances and maintenance of a constant fluid environment in the body (Homeostasis).

Animals↗
PubMed1977

Hypotensive activity of sodium nitroprusside and structurally related complexes of sodium pentacyanoamine ferrate with amylnitrite, butylnitrite and n-octylamine.

Complexes of sodium pentacyanoamine ferrate (TPF) with amylnitrite and with butylnitrite showed hypotensive activity equal to that of sodium nitroprusside, as tested intravenously, in unanesthetized , instrumented Rhesus, monkeys. The complex with n-octylamine, on the other hand, had significantly lower activity. These complexes produced only marginal hypotensive effects when administered orally in a dose of 10 mg/kg to spontaneously hypertensive rats.

Administration, Oral↗
PubMed1984

[Morphogenetic role of the cortical cytoskeleton and plasma membrane of the ovum].

The classical embryological conception of egg cortex localization of morphogenetic determinants is interpreted in terms of current data on cell cortex and cell surface organization. The egg surface complex that involves cortical cytoskeleton--oolemma (stabilized with transmembrane linkage between the cytoskeleton and ligands of egg envelope extracellular matrix) presumably ensures storage of cortical morphogenetic information, i.e. the spatial memory of egg and zygote as a heterogeneous distribution of membrane and cortex components. Any of the rigid cortical complex component--membrane receptors, structural cytoskeletal proteins and also embedded in cortical gel-like framework of actin filaments RNP's and non-structural proteins (e.g. enzymes) may function as possible morphogenetic determinants. The coupling of general cortical rigidity and local contractility during the cleavage may be accounted (after Condeelis, 1981) for the actin-myosin interaction following a local dissociation of the stiff structural complex of actin--actin-binding proteins.

Actins↗