Karl Knobloch

Antibacterial and antifungal properties of essential oil components

ABSTRACT The solubility in water of essential oil constituents is directly related to their ability to penetrate the cell walls of a bacterium or fungus. The antimicrobial activity of essential oils is due to their solubility in the phospholipid bilayer of cell membranes. Terpenoids which are characterized by their lability have been found to interfere with the enzymatic reactions of energy metabolism.

Inhibitory effects of essential oil components on growth of food-contaminating fungi.

ZusammenfassungDie antimykotische Wirkung mehrerer Komponenten von ätherischen Ölen wurde mit einem Agar-Diffusionstest bestimmt. Die untersuchten Substanzen sind strukturell mit Eugenol verwandt. Äquimolare Mengen wurden an mehr als zehn Schimmelpilzstämmen getestet, von denen bekannt ist, daß sie Lebensmittel kontaminieren. Iso-Eugenol, Zimtaldehyd, Carvacrol, Eugenol und Thymol zeigten die stärkste antimykotische Wirkung. Der unempfindlichste Stamm war einPenicillium verrucosum var.cyclopium, während einP. viridicatum den sensibelsten darstellte. Einige Struktur-Wirkungsbeziehungen konnten in Betracht gezogen werden. Eine aktive Konfiguration bei phenolischen Verbindungen zur Entfaltung antimykotischer Wirkung scheint die freie Hydroxylgruppe in Verbindung mit einem Aklkylsubstituenten zu sein.SummaryThe antifungal activity of several components of essential oils were evaluated using a paper-disk method. The substances investigated are structurally related to eugenol. Equimolar amounts were tested on more than ten fungal strains known to contaminate food. Iso-eugenol, cinnamaldehyde, carvacrol, eugenol and thymol revealed the strongest antifungal activity. The most resistant strain appeared to bePenicillium verrucosum var.cyclopium, and the most sensitive wasP. viridicatum. Some of the structural effects were considered, including a free hydroxyl group[

The enzymatic system thiosulfate: Cytochrome c oxidoreductase from photolithoautotrophically grown Chromatium vinosum

Chromatium vinosum cells form a vesicular type intracytoplasmic membrane system during phototrophic growth on thiosulfate.—An enzyme protein transferring electrons from thiosulfate to cytochromes of type c was enriched from S-144. The colorless thiosulfate: cytochrome c oxidoreductase was characterized by a molecular weight of 36,000 (after dodecylsulfate treatment) and 35,000 (by gel filtration). Isoelectric focusing revealed a pI range of 4.4 to 4.7. Apparent Km values for the cytochromes tested were in the μM range. — The endogenous electron acceptor compound, isolated from the chromatophore fraction P-144, was found to be a membrane-bound cytochrome c-552. The homogeneous cytochrome protein had an average pI value of 4.65 and a molecular weight of 71,500 determined by gel filtration. By dodecylsulfate electrophoresis it was cleaved into two proteins representing particle weights of 45,000 and 20,000.

Über ätherische Öle des Ingwer,Zingiber oficinalis Roscoe

SummaryEssential oils from ginger rhizomes of different origins, such asZingiber officinalis Rosc. from India and Australia, differ remarkably in their terpenoid compositions. The main components of Indian ginger oil are the sesquiterpenoid hydrocarbons, arcurcumene, zingiberene, α-farnesene,β-bisabolene andβ-sesquiphellandrene. However, the essential oil from the Australian ginger consists mainly of the monoterpenoid hydrocarbons, camphene and phellandrene, and their oxygen-containing derivatives neral, geranial and 1,8-cineol.ZusammenfassungDie etherischen Öle aus Rhizomen von Ingwer (Zingiber officinalis Rosc.) indischer und australischer Herkunft unterscheiden sich grundlegend in ihrer Zusammensetzung. Hauptbestandteile des aus Indischem Ingwer gewonnenen Öls sind die Sesquiterpenkohlenwasserstoffe ar-Curcumen, Zingiberen, α-Farnesen,β-Bisabolen undβ-Sesquiphel-landren. Hingegen besteht das etherische Öl des Australischen Ingwwes hauptsächlich aus den Monoterpenkohlenwasserstoffen Camphen und Phellandren und deren sauerstoffhaltigen Derivaten Neral, Geranial und 1,8-Cineol.

Über die Komponenten des atherischen Öls aus Estragon (Artemisia dracunculus L.)

Summary30 compounds could be identified in the essential oil of tarragon (Artemisia dracunculus L.). The main components were sabinene, methyl eugenol, estragol and elemicine. The content of essential oil per unit dry weight had a characteristic seasonal dependence.ZusammenfassungIm ätherischen Öl des Estragons (Artemisia dracunculus L.) wurden 30 Einzelkomponenten identifiziert. Als Hauptkomponenten fanden sich Sabinen, Methyleugenol, Estragol und Elemicin. Der Gehalt an ätherschm Öl zeigte eine charakteristische jahreszeitliche Abhängigkeit.

On the quantitation of bacteriochlorophyll in chromatophore suspensions from purple bacteria

Abstract A direct photometric quantitation of bacteriochlorophyll (BChl) at 375 nm in aqueous chromatophore suspensions from various purple bacteria is described. The assay is rapid and reproducible. It is utilized easily for processing large numbers of samples and is as sensitive as extraction methods usually applied today. Drawbacks of extraction methods, particularly not quantitative extractions, photo- and autooxidation are avoided. There is good linearity up to 20 μg BChl/ml suspension, and no interference by buffers is observed.

On the Enzymatic System Thiosulfate-Cytochrome c-Oxidoreductase

Inorganic sulfur compounds in various reduced stages serve as essential electron donors for a variety of microorganisms. The photosynthetic sulfur bacteria depend on light as their energy source in an anaerobic environment (photolithotrophs). The chemolithotrophs lack chlorophyll and use the inorganic reduced sulfur as the source of energy and electrons under aerobic conditions (Fig. 1).

The enzymatic system thiosulfate: Cytochrome c oxidoreductase from photolithoautotrophically grown Rhodopseudomonas palustris

Rhodopseudomonas palustris cells, characterized by a lamellar type intracytoplasmic chromatophore membrane system after phototrophic growth, yielded a crude supernatant cell-free fraction (S-144) after ultracentrifugation which retained the contents of both the cell compartments. After thiosulfate-dependent growth, a protein system was isolated from S-144 which catalyzed the thiosulfate-linked reduction of an endogenous c-type cytochrome. — The colorless oxidoreductase protein, after purification to homogeneity, revealed a molecular weight of 93,000 and, after SDS treatment, a particle weight of 48,000. It was focused at an average pI of 5.45. Apparent Km values for several substrates were in the μM range. The electron acceptor for thiosulfate oxidation was found to be a cytochrome c from S-144. The homogeneous acceptor protein, at liquid nitrogen temperature, exhibited absorption maxima at 549.0, 518.5 and 418.0 nm, and shoulders at 525.5, 512.0 and 508.0 nm. Its molecular weight was found to be 17,000 (gel filtration) and 16,000 (SDS gel electrophoresis). It was characterized by a pI of 10.0. Its midpoint redox potential of Em,7.0=+228 mV was determined by redox titrations and the value of +205 mV by spectrophotometric calculations.

Phosphatidyl cholin as the main phospholipid within essential oil residues from the orange fruit

ZusammenfassungDas ätherische Öl von Orangen verschiedener Herkunft hinterläßt nach der Aufarbeitung und Reinigung ein dunkelrotes Öl. Dieser Rückstand enthält Phospholipide. Phosphatidyl-Cholin wurde als die hauptsächlich vorkommende Komponente identifiziert.SummaryThe essential oil obtained from oranges of different origin leaves a dark red oil after purification. The residue holds phospholipids. Phosphatidyl cholin has been identified as the main compound.

Photosynthetische Sulfid-Oxydation Grüner Pflanzen

Hydrogen sulphide is an essential electron donor in the photosynthesis of sulphur bacteria. In addition, it has been known to be an inhibitor of photosynthesis in green plants. More specifically, it is assumed that sulphide interacts with the oxygen-evolving system. If the view is accepted that there is a more or less uniform concept of photosynthesis which is valid for all assimilating organisms, the role of sulphide as an inhibitor in green plant photosynthesis hardly seems to be acceptable.Our experiments show that sulphide indeed depresses photosynthetic oxygen evolution. However, during the period of decreased oxygen liberation, sulphide at a concentration up to 10(-3) M is oxidized by the living cells. During the oxidation of sulphide, photosynthetic oxygen evolution simultaneously increases. Oxidation of sulphide proceeds only in the light and in the presence of CO2. This new photosynthetic reaction has characteristics in common with CO2 assimilation. The rate of the sulphide oxidation reaction is comparatively low: when there is normal activity, 10 to 15 molecules of O2 are liberated while one molecule of S(--) is oxidized.Organisms tested thus far were blue-green, green and red algae as well as the flowering plants Lemna and Spirodela. Each of these plants, when photosynthetically active, was capable of oxidizing sulphide photosynthetically, indicating that S(--) may also play the role of a (secondary) electron donor in the photosynthesis of green plants.SummaryHydrogen sulphide is an essential electron donor in the photosynthesis of sulphur bacteria. In addition, it has been known to be an inhibitor of photosynthesis in green plants. More specifically, it is assumed that sulphide interacts with the oxygen-evolving system. If the view is accepted that there is a more or less uniform concept of photosynthesis which is valid for all assimilating organisms, the role of sulphide as an inhibitor in green plant photosynthesis hardly seems to be acceptable.Our experiments show that sulphide indeed depresses photosynthetic oxygen evolution. However, during the period of decreased oxygen liberation, sulphide at a concentration up to 10-3 M is oxidized by the living cells. During the oxidation of sulphide, photosynthetic oxygen evolution simultaneously increases. Oxidation of sulphide proceeds only in the light and in the presence of CO2. This new photosynthetic reaction has characteristics in common with CO2 assimilation. The rate of the sulphide oxidation reaction is comparatively low: when there is normal activity, 10 to 15 molecules of O2 are liberated while one molecule of S-- is oxidized.Organisms tested thus far were blue-green, green and red algae as well as the flowering plants Lemna and Spirodela. Each of these plants, when photosynthetically active, was capable of oxidizing sulphide photosynthetically, indicating that S-- may also play the role of a (secondary) electron donor in the photosynthesis of green plants.Zusammenfassung1.Die Tatsache, daß Sulfid bei der Bakterien-Photosynthese einen essentiellen Elektronendonator darstellt, andererseits (wie seit über 40 Jahren bekannt) ein Photosynthesegift grüner Pflanzen sein soll, war neben Hinweisen und anderslautenden Vermutungen aus der Literatur Ausgangspunkt der Untersuchungen.2.Es wird eine einfache und schnelle Methode zur quantitativen S---Bestimmung beschrieben.3.Die getesteten Objekte waren einzellige Blau-, Grün- und Rotalgen sowie die Blütenpflanzen Lemna und Spirodela. Alle geprüften photosynthetisch aktiven Organismen waren zu einer S---Oxydation befähigt, die a) nur im Licht möglich ist; b) einen CO2-Gehalt des Mediums voraussetzt; c) temperaturabhängig its; d) bei erhöhter Photosynthese gesteigert und bei verminderter Photosynthese herabgesetzt ist; e) einer offenbar jahresperiodischen Rhythmik unterliegt.4.Es handelt sich um einen photosynthetischen Vorgang (“Photosynthetische Sulfidoxydation grüner Pflanzen”), wobei die S---Oxydation relativ langsam abläuft. 10 bis 15 Moleküle O2 werden entwickelt, während ein Molekül S-- oxydiert wird.