Zur Kenntnis der Phlobaphenkörper in Früchten einigerMalus-Arten

Zusammenfassung Die von Molisch in der Epidermis und dem Hypoderm der Weinbeeren entdeckte Erscheinung, daß sich an der den Sonnenstrahlen ausgesetzten Seite dieser Früchte aus flüssigem Gerbstoff feste und gefärbte Phlobaphenballen bilden, wird auch in der Epidermis der Früchte vonMalus Toringo undM. floribunda beobachtet. Da — besonders beiMalus-Toringo- Früchten — unter der Einwirkung des Lichtes an der besonnten Fruchtseite reichlich auch Anthozyan erscheint, kommt es an dieser Seite zu einer mosaikartigen Verteilung der Zellen, von denen die einen feste, gelb bis gelbbraun gefärbte Phlobaphenkörper (verfestigte Vakuolen), die anderen flüssige, anthozyanführende Vakuolen enthalten. In manchen Fällen befinden sich beide Arten von Vakuolen in ein und derselben Zelle. Einige feste Vakuolen (Phlobaphenkörper) sind in einer intrazellulären Membran eingekapselt, deren Gerüstsubstanz Zellulosecharakter hat.In den flüssigen, ungefärbten Vakuolen, aus denen Phlobaphenkörper entstehen, wurde die Anwesenheit des Gerbstoffes sichergestellt. Es wird aber vermutet, daß den Gerbstoffen auch andere kolloide Substanzen beigemengt sind.Die Untersuchung wurde während meines dreimonatigen Aufenthaltes im Pflanzenphysiologischen Institut der Universität Graz durchgeführt. Dem Vorstand des Institutes, Herrn Professor Dr. F. Weber, sowie Herrn Professor Dr. O. Härtel und Frau Dr. L. Brat danke ich bestens für ihr liebenswürdiges Entgegenkommen.     

Phycobilisomes from the mutant cyanobacterium Synechocystis sp. PCC 6803 missing chromophore domain of ApcE

Phycobilisome (PBS) is a giant photosynthetic antenna associated with the thylakoid membranes of cyanobacteria and red algae. PBS consists of two domains: central core and peripheral rods assembled of disc-shaped phycobiliprotein aggregates and linker polypeptides. The study of the PBS architecture is hindered due to the lack of the data on the structure of the large ApcE-linker also called L_CM. ApcE participates in the PBS core stabilization, PBS anchoring to the photosynthetic membrane, transfer of the light energy to chlorophyll, and, very probably, the interaction with the orange carotenoid protein (OCP) during the non-photochemical PBS quenching. We have constructed the cyanobacterium Synechocystis sp. PCC 6803 mutant lacking 235 N-terminal amino acids of the chromophorylated PBL_CM domain of ApcE. The altered fluorescence characteristics of the mutant PBSs indicate that the energy transfer to the terminal emitters within the mutant PBS is largely disturbed. The PBSs of the mutant become unable to attach to the thylakoid membrane, which correlates with the identified absence of the energy transfer from the PBSs to the photosystem II. At the same time, the energy transfer from the PBS to the photosystem I was registered in the mutant cells and seems to occur due to the small cylindrical CpcG2-PBSs formation in addition to the conventional PBSs. In contrast to the wild type Synechocystis, the OCP-mediated non-photochemical PBS quenching was not registered in the mutant cells. Thus, the PBL_CM domain takes part in formation of the OCP binding site in the PBS.     

Research on the ability of propionic acid and vitamin B12 biosynthesis by <Emphasis Type="Italic">Propionibacterium freudenreichii</Emphasis> strain T82

The purpose of this study was to determine the potential for biosynthesis of propionic acid and vitamin B12 by Propionibacterium freudenreichii T82 in a medium containing various sources of carbon (glucose, fructose, and saccharose). These sugars are present in apple pomaces, which are the waste from the production of apple juice. Using statistical analysis design of experiments (DoE), the results allowed us to determine which sugars (carbon sources) exert the most beneficial influence on the biosynthesis of propionic acid and cobalamin. The highest production of propionic acid by the tested bacterial strain was obtained in a medium in which glucose accounted for at least 50% of the available carbon sources. Depending on the culture medium, the concentration of this metabolite ranged from 23 to 40 g/L. P. freudenreichii T82 produced the smallest amount of acid in medium in which the dominant nutrient source was saccharose. The results obtained indicated an inverse relationship between the amount of acid produced by the bacteria and vitamin B12 biosynthesis. Because of the high efficiency of propionic acid biosynthesis by P. freudenreichii T82, the prospect of using this strain to obtain propionate with the simultaneous disposal of waste materials (such as apple pomaces) which contain glucose and/or fructose is very promising.     

Comparative effects of ammonium,nitrate and urea on growth and photosynthetic efficiency of three bloom‐forming cyanobacteria

相似文献   

Screening of the Antarctic marine sponges (Porifera) as a source of bioactive compounds

Sponges (Porifera) currently represent one of the richest sources of natural products and account for almost half of the pharmacologically active compounds of marine origin. However, to date very little is known about the pharmacological potential of the sponges from polar regions. In this work we report on screening of ethanolic extracts from 24 Antarctic marine sponges for different biological activities. The extracts were tested for cytotoxic effects against normal and transformed cell lines, red blood cells, and algae, for modulation of the activities of selected physiologically important enzymes (acetylcholinesterase, butyrylcholinesterase, and α-amylase), and for inhibition of growth of pathogenic and ecologically relevant bacteria and fungi. An extract from Tedania (Tedaniopsis) oxeata was selectively cytotoxic against the cancer cell lines and showed growth inhibition of all of the tested ecologically relevant and potentially pathogenic fungal isolates. The sponge extracts from Isodictya erinacea and Kirkpatrickia variolosa inhibited the activities of the cholinesterase enzymes, while the sponge extracts from Isodictya lankesteri and Inflatella belli reduced the activity of α-amylase. Several sponge extracts inhibited the growth of multiresistant pathogenic bacterial isolates of different origins, including extended-spectrum beta-lactamase and carbapenem-resistant strains, while sponge extracts from K. variolosa and Myxilla (Myxilla) mollis were active against a human methicillin-resistant Staphylococcus aureus strain. We conclude that Antarctic marine sponges represent a valuable source of biologically active compounds with pharmacological potential.