Mutagenic action of 2-ethyl-2-phenyl-ethyleneimine

Zusammenfassung Die Wirkung von 2-Äthyl-2-phenyl-äthylenimin auf die Induktion von Chlorophyllmutanten bei der Gerste wurde beschrieben. Nach Behandlung mit dem Agens (5 in Wasser) war die Mutationsfrequenz 5,2% für die Ährennachkommenschaften. Die maximale Anzahl Mutanten gehörte zur Viridisklasse (57,9%). Bei höheren Konzentrationen wurde ein beträchtlicher Letaleffekt beobachtet.     

Strukturspezifischer Abbau von Polypeptid-Metall-Komplexen III 1. Abbau des Ni2+-Angiotensin II-Komplexes durch H2O2 2

Summary The octapeptide Val⁵-Angiotensin II-Asp¹--amide is split into characteristic fragments by hydrogen peroxide, when complexed with Ni²⁺; this degradation does not occur with the Cu²⁺ complex, presumably because an active ternary peroxo complex cannot be formed.     

Erythropoietic effects of PGE2 and 2 endoperoxide analogs

Summary The erythropoietic effects in exhypoxic polycythemic mice of two endoperoxide analogs were assessed and compared with PGE₂. The 9a, 11a epoxymethano analog (U-44069) was found to be a much more potent erythropoietic stimulus than the 11a,9a analog (U-46619) or PGE₂.This work was supported by a Senior Research Grant-in-Aid from the American Heart Association-Louisiana (DMG) and USPHS Grant No. AM 13211 (JWF).     

Three classes of C2H2 zinc finger proteins

C2H2 zinc finger proteins probably comprise the largest family of regulatory proteins in mammals. Most zinc fingers bind to a cognate DNA. In addition to DNA, many of the proteins also bind to RNA or protein, and some bind to RNA only. The binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. C2H2 zinc finger proteins contain from 1 to more than 30 figures. Based on the number and the pattern of the fingers, most of the proteins can be classified into one of three groups: triple-C2H2, multiple-adjacent-C2H2, and separated-paired-C2H2 finger proteins. In contrast to proteins with triple-C2H2 fingers, proteins with multiple-adjacent-C2H2 fingers can bind multiple, different ligands. Proteins with a number of separated-paired fingers bind to the target by means of only a single pair.     

Zur Biochemie autoxydabler,H2O2-bildender Verbindungen

Summary Cytostatic -aminoketones are found to produce H₂O₂ on autoxidation. Possible pathways of radical and peroxidative reactions in cytostatic therapy are discussed.     

Isolation of 2-acetyl-2-decarboxamidotetracycline from cultures ofStreptomyces psammoticus

Riassunto LoStreptomyces psammoticus produce in coltura sommersa oltre a preponderanti quantità di tetraciclina anche piccole quantità di 2-acetil-2-decarbossamidotetraciclina. Sono riportati i dati cromatografici per distinguere qualitativamente la 2-acetil-2-decarbossamidotetraciclina dalle più comuni tetracicline.     

Soybean photosynthesis: simultaneous14CO2 and O2 estimates

Summary A method of estimating the photosynthetic rate of soybean leaves using an oxygen electrode is presented. The procedure is rapid, requires small samples and compares favourably with estimates by other techniques. Light saturation occurs at 1200 E·m^–2·sec^–1. The apparent K_m for HCO ₃ ^– is 3.2 mM at pH 7.6.     

The H2O2-production by polymorphonuclear leucocytes during phagocytosis

Riassunto Si può dimostrare un accumulo di H₂O₂ in leucociti polinucleati di essudato di cavia o di sangue umano durante la fagocitosi in presenza di KCN 2 mM. La produzione di H₂O₂ e l'attività della perossidasi si considerano importanti per l'azione battericida.     

Synthesis of 2-nitrosofluorene by peracetic acid oxidation of 2-aminofluorene

Zusammenfassung Lösungen von 2-Aminofluoren in Eisessig färben sich nach Zugabe von H₂O₂ bald tiefgrün. Das bei der Oxydation mit Peressigsäure entstehende 2-Nitrosofluoren lässt sich leicht extrahieren und nach Säulentrennung rein gewinnen. Dieses Verfahren ist einfacher und schneller als andere bekannte Methoden.     

Gonadotrophin-releasing activity of histones H2A and H2B

We report that histones H2A and H2B possess gonadotrophin-releasing activity in vitro and assess the signal transduction pathways involved in these effects. Perifused and incubated rat anterior pituitary (AP) cells were used, and luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by RIA. Perifusion of cells with histone H2A (30 μM) or histone H2B (30 μM), markedly stimulated LH release but failed to elicit any FSH response. Cells incubated with 6 or 30 μM histone H2A showed a dose- and time-dependent stimulatory effect on both LH and FSH release which was blocked by 1 μM peptide MB35, an 86–120 amino acid fragment of histone H2A. Incubation of pituitary cells with gonadotrophin-releasing hormone (GnRH) and histones H2A or H2B showed a stimulatory effect on LH and FSH release which was similar to the sum of the separate effects. Trifluoperazine, as well as ethylene glycol bis(b-aminoethyl ether) N,N,N′,N′-tetraacetic acid (EGTA), alone or in the presence of the calcium ionophore A23187, significantly reduced the response of AP cells to histones. Various cyclic adenosine monophosphate (cAMP) enhancers had no effect on histone-stimulated release of gonadotrophins in incubated AP cells. Our results confirm previous evidence that histones may act as hypophysiotrophic signals. Calcium- and diacylglycerol-associated pathways, but not cAMP, appear to participate in these effects. Received 11 August 1997; received after revision 20 January 1998; accepted 26 January 1998     

Inhibition of monoamine oxidase by 3-amino-2-oxazolidinone and 2-hydroxy-ethylhydrazine

Zusammenfassung Die MAO-hemmende Aktivität von 3-Amino-2-Oxazolidinon und von 2-Hydroxy-Äthylhydrazin wird beschrieben.     

CAP2, cyclase-associated protein 2, is a dual compartment protein

Cyclase-associated proteins (CAPs) are evolutionarily conserved proteins with roles in regulating the actin cytoskeleton and in signal transduction. Mammals have two CAP genes encoding the related CAP1 and CAP2. We studied the distribution and subcellular localization of CAP1 and CAP2 using specific antibodies. CAP1 shows a broad tissue distribution, whereas CAP2 is significantly expressed only in brain, heart and skeletal muscle, and skin. CAP2 is found in the nucleus in undifferentiated myoblasts and at the M-line of differentiated myotubes. In PAM212, a mouse keratinocyte cell line, CAP2 is enriched in the nucleus, and sparse in the cytosol. By contrast, CAP1 localizes to the cytoplasm in PAM212 cells. In human skin, CAP2 is present in all living layers of the epidermis localizing to the nuclei and the cell periphery. In in vitro studies, a C-terminal fragment of CAP2 interacts with actin, indicating that CAP2 has the capacity to bind to actin.     

Ablation of cyclase-associated protein 2 (CAP2) leads to cardiomyopathy

Cyclase-associated proteins are highly conserved proteins that have a role in the regulation of actin dynamics. Higher eukaryotes have two isoforms, CAP1 and CAP2. To study the in vivo function of CAP2, we generated mice in which the CAP2 gene was inactivated by a gene-trap approach. Mutant mice showed a decrease in body weight and had a decreased survival rate. Further, they developed a severe cardiac defect marked by dilated cardiomyopathy (DCM) associated with drastic reduction in basal heart rate and prolongations in atrial and ventricular conduction times. Moreover, CAP2-deficient myofibrils exhibited reduced cooperativity of calcium-regulated force development. At the microscopic level, we observed disarrayed sarcomeres with development of fibrosis. We analyzed CAP2’s role in actin assembly and found that it sequesters G-actin and efficiently fragments filaments. This activity resides completely in its WASP homology domain. Thus CAP2 is an essential component of the myocardial sarcomere and is essential for physiological functioning of the cardiac system, and a deficiency leads to DCM and various cardiac defects.