Library

Notes: SYNOPSIS. Antibodies to purified chloroplast preparations from Euglena gracilis var. bacillaris were prepared in rabbits. Success was achieved only after removal of lipids by forming acetone powders af chloroplasts. Ouchterlony agar-diffusion procedures showed that light-grown cells (containing chloroplasts) have at least 3 antigens reacting with these antibodies and not detectable in the dark-grown cells (which contained proplastids but no chloroplasts), The antigens uniquely associated with the chloroplast appear sequentially during the development of the proplastid into the chloroplast on light induction of the dark-grown cells. The first of these antigens appears at about 10 hr of development. Mutants of the parent strain showed varying numbers of antigens which were cor-related with their capacities to form plastid structures. Cells developing abnormal chloroplasts at low light intensities did not reveal any antigenic differences from cells developing normal chloroplasts. Various antigenic bands were also found which were common to all cell types studied. These can be ascribed either to non-chloroplast contaminants in the original preparation used to immunize the rabbits or to antigens which, although not in the chloroplasts, are cross-reacting with chloroplast materials. In the case of the dark-grown cells, it is likely that portions of the proplastids are cross-reacting with chloroplast materials.

Notes: Summary The possibility that 32PO 4 3- (32Pi) labeling of both chloroplast and non-chloroplast RNAs during light-induced chloroplast development in Euglena is due, in part, to the break-down of existing RNAs and their resynthesis into labeled RNAs has been examined by comparing the RNA content of dark-grown, non-dividing cells after completion of light-induced chloroplast development with that of identical cells maintained in darkness for the same period of time. The involvement of the photo-conversion of protochlorophyll to chlorophyll and other photoreceptor systems in the labeling of RNA during chloroplast development has been considered by comparing the labeling pattern obtained with wild-type cells with the patterns obtained with mutants of Euglena which either lack detectable amounts of protochlorophyll and chlorophyll or form only rudimentary chloroplasts upon light induction. No significant difference in RNA content between dark-grown, non-dividing cells containing fully developed chloroplasts and the same cells maintained in darkness for the development period can be detected. This observation is interpreted to mean that in non-dividing cells precursors for chloroplast-associated RNAs are derived from pools and pre-existing RNAs, including non-chloroplast RNAs, and that the matebolic entrapment of 32Pi involves a light-dependent turnover and DNA-directed RNA synthesis in wild-type cells. The RNA profiles on sucrose gradients of mutants of Euglena show no remarkable deviation from the profile established for wild-type cells. The labeling patterns obtained after 24 hours of incubation in light and in darkness differ from that obtained for wild-type cells in that all mutants show less of a light-minus-dark difference than wild-type and that mutants lacking plastid-associated DNA and detectable amounts of chlorophyll incorporate considerably more 32Pi into RNA in darkness than wild-type. One such mutant shows no significant difference in its light-dark labeling pattern. These observations indicate that cells possessing normal proplastids capable of forming functional chloroplasts regulate metabolism of RNA in darkness in a different manner than with either rudimentary chloroplasts or containing no detectable plastids structures. The possible involvement of more than one photoreceptor system in metabolic control is discussed.

Notes: Zusammenfassung Die A-ähnliche Substanz aus Pepton sowie die Gruppenmerkmale A und B aus menschlichem Speichel werden durch manche Stämme des Gasbrandbacillus Fränkel-Welsh abgebaut. Eine entsprechende Wirkung anderer Bakterien, darunter stark proteolytischer und peptolytischer Arten, konnte in Bestätigung früherer Beobachtungen bisher nicht festgestellt werden.

Notes: Zusammenfassung Am Beispiel der Poliomyelitis wird gezeigt, daß die epidemiologischen Besonderheiten einer Infektionskrankheit in der Blutgruppenverteilung der Erkrankten zum Ausdruck kommen können. Da die Poliomyelitis am häufigsten und schwersten bei Personen aus noch wenig durchseuchten, im allgemeinen also auch vom großen Verkehr abgelegenen Gebieten auftritt, so ist zu erwarten, daß die Poliomyelitiskranken eines größeren Bezirkes (unter Umständen auch schon einer größeren Stadt) in ihrer Blutgruppenverteilung nicht dem Durchschnitt der Gesamtbevölkerung entsprechen, sondern sich der Gruppenverteilung der abgelegenen Gebiete nähern. Die im Schrifttum vorhandenen Zahlenunterlagen entsprechen dieser Erwartung. In einem Gebiet, wo die Verhältnisse derartig liegen, kann leicht eine unmittelbare Verknüpfung zwischen Krankheitsempfänglichkeit bzw. Widerstandsfähigkeit und einer bestimmten Blutgruppevorgetäuscht werden.