Invertase in cell-free culture fluids of Streptococcus mutans strain SL-1.

Intervase from extracellular culture fluids of S. mutans strain SL-1 was shown to have the same characteristics as intracellular invertase from the same strain. The data indicate that intracellular invertase is released into the culture fluids primarily during the late log and stationary phases of growth.     

Estimation of emulsification of hydrocarbons in culture fluids

Zusammenfassung Eine mikroskopische Methode zur Bestimmung des Emulsionsgrades von Kohlenwasserstoffen in Kultursubstraten wird beschrieben. Der jeweilige Zustand solcher Öl/Wasser-Emulsionen in bewachsenen Fermentationsmaischen wird für die Bestimmung mittels Gelatine stabilisiert. Einflussfaktoren und Bedeutung des Emulgierens werden diskutiert.     

Establishment of an epithelial cell strain from calf liver in continuous culture

Zusammenfassung Die Isolierung einer Zell-Linie aus fötaler Kalbsleber wird beschrieben. Die Zellen wachsen in epithelialer Schicht und sind durch Kittsubstanz miteinander verklebt. Nach der fünfzigsten Passage scheinen noch immer spezifische Leberenzyme anwesend zu sein, so dass die Zell-Linie morphologisch und biochemisch als Leberepithel betrachtet werden kann.     

A bacteriocinogenic type 1 strain ofKlebsiella pneumoniae

Résumé La souche 1.2 (N.C.T.C. 5054) deKlebsiella pneumoniae est bactériocinogène. Sur 47 souches de Klebsiella étudiées 25% se sont révélées sensibles à cette bactériocine.

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We are grateful to ProfessorJ. P. Duguid, Drs.B. H. Park, I. Ørskov, andY. Hamon for strains and information.     

The triangular halophilic archaebacteriumHaloarcula japonica strain TR-1

We have isolated a predominantly triangular disc-shaped halophilic archaebacterium, strain TR-1, from a Japanese saltern soil. The taxonomical characteristics of this strain led us to propose a new speciesHaloarcula japonica. The cell division ofHa. japonica strain TR-1 was analyzed by time lapse microscopic cinematography. Cell plates were laid down asymmetrically, generating triangular or rhombic daughter cells which then separated. We have demonstrated the occurrence of a glycoprotein with an apparent molecular mass of 170 kDa on the cell surface ofHa. japonica. The release of this cell surface glycoprotein (CSG), accompanied by a morphological change (triangular to spherical), was observed after lowering the magnesium concentration in the medium. Thus, it is likely that the CSG plays an important role in maintaining the characteristic shape ofHa. japonica.     

Platelet protein synthesis studied in a cell-free system

Zusammenfassung Zwei Klassen von Polyribosomen wurden von menschlichen Thrombozyten isoliert. Diese Polysome synthetisierten myosin- und actinähnliche Proteine in einem zellfreien System. Isolierung und Reinigung dieser Eiweisskörper zeigten deren Bildung in einer nativen Form an. Analyse der polysomalen Grösse indizierte die Synthese dieser Proteine an monocystronischen RNA-Molekülen.     

Invertase activity in the midgut ofSarcophaga ruficornis andMusca domestica (diptera: Insecta)

Summary The pH for the optimum activity of the midgut invertase was 5.5 in the adults ofS. ruficornis, 6.0 in its larvae and adults ofM. domestica and 6.5 in the larvae of the latter fly. The optimum temperature was 50°C. Enzyme activity was retarded by the addition of glucose and fructose.     

Analysis of nuclear apoptotic process in a cell-free system

We report an analysis of the apoptotic process of mouse liver nuclei induced in a cell-free carrot cytosol system by cytochrome c. Typical characteristics of apoptosis were observed, such as chromatin condensation, margination, apoptotic bodies and DNA ladders. Furthermore, transmission and scanning electron microscope analysis of the apoptotic nuclei detected chromatin-free nuclear vesicles before apoptotic bodies appeared at a comparatively late phase. When AC-YVAD-CHO, an inhibitor of caspase 6, was introduced into the system, these vesicles and apoptotic bodies disappeared completely within our study sections. We confirmed the results using whole-mount electron microscopy, and found that although the nuclear lamina was destroyed early, the nuclear matrix largely remained intact during the course of apoptosis. The nuclear matrix played an important role in maintaining the integrity of apoptotic cells and connecting the apoptotic bodies and apoptotic nucleus. Received 29 September 2000; revised 10 December 2000; accepted 13 December 2000     

Estimation of decamethonium in biological fluids

Résumé Les auteurs ont modifié la méthode de dosage de sels de méthonium, proposée dans leur travail précédent, pour rendre possible son application à la recherche du C₁₀ dans les sérums et les urines.Cette méthode est rigoureusement spécifique pour la détermination du décaméthonium dans le sérum entre 100 e 500/ml mais moins spécifique pour les urines.     

Proteolytic activity on endogeneous substrates in cell-free extracts ofTrypanosoma cruzi

Summary Cell-free extracts ofTrypanosoma cruzi contain proteolytic activity able to degrade endogenous substrates. The activity was maximal at pH 3 to 4, had an optimal temperature of 65°C, and was strongly inhibited by N--p-tosyl-L-lysine chloromethyl ketone.This investigation received financial support from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, the Fundación Julio Cherny, and the Ministerio de Salud Pública y Medio Ambiente de la República Argentina. The authors gratefully acknowledge the technical assistance of Mr Esteban Bontempi.     

Apparent arylsulfatase A activity in excretory fluids

Summary Arylsulfatase activity has been demonstrated in rat and human parotid and submandibular saliva indicating that oral bacteria are not the only source of salivary sulfatase activity. Activity was also observed in human sweat, tears and in snake venom.Acknowledgments. We extent appreciation to Drs.C. Dawes andK. Abe for assistance in saliva collection, to Dr.K. W. Stewart who provided fresh snake venoms and to Dr.E. T. Pritchard in whose laboratory this study was conducted. Supported by grant Nr. MT 3536 from MRC of Canada.     

Behaviour of a guanidine-dependent strain of poliovirus 1 in sucrose density and pH gradients

Riassunto La densità in gradiente di saccarosio ed il punto isoelettrico delle particlle virali di poliovirus guanidino-dipendentri non differiscono da quelle del virus guanidino-sensibile di origine.     

Invertase activity in the gut of 6th instar larvae ofSpodoptera mauritia Boisd. (Noctuidae,Lepidoptera)

Summary Invertase activity has been studied in the fore-, mid- and hindgut of the 6th instar larva ofSpodoptera mauritia. The highest activity was in the midgut except during the early hours of the larval period when the foregut showed comparatively increased activity. The hindgut invertase activity may be from the voiding of enzyme along with the undigested food.Acknowledgments. The authors wish to thank the Department of Zoology, for providing the facilities for this work. The senior author gratefully acknowledges the junior research fellowship from the University of Calicut.