scholarly journals Alternative pathways of zeaxanthin biosynthesis in a Flavobacterium species. Experiments with nicotine as inhibitor

1974 ◽  
Vol 144 (2) ◽  
pp. 231-243 ◽  
Author(s):  
J C B McDermott ◽  
D J Brown ◽  
G Britton ◽  
T W Goodwin
Keyword(s):  
Cyclization Reaction ◽  
Biosynthetic Pathways ◽  
Anaerobic Conditions ◽  
Anaerobic Process ◽  
Alternative Pathways ◽  
Nicotine Concentration ◽  
Β Carotene

In Flavobacterium R1519, nicotine blocks zeaxanthin biosynthesis by specifically inhibiting the cyclization reaction. Lycopene (at high nicotine concentrations, e.g. 7.5mm) and rubixanthin (at low nicotine concentration, e.g. 1mm) replace zeaxanthin as the main carotenoid. On removal of the nicotine lycopene is converted into β-carotene under anaerobic conditions and into zeaxanthin in the presence of O2. The conversion in vivo of β-carotene into zeaxanthin was also demonstrated. Cyclization (an anaerobic process) thus precedes hydroxylation (O2-requiring) in the biosynthesis of zeaxanthin. The conversion in vivo of rubixanthin into β-cryptoxanthin and into zeaxanthin was demonstrated, thus indicating the operation of alternative pathways of zeaxanthin biosynthesis. Several alternative biosynthetic pathways are considered and the results are also discussed in terms of reaction sequences of carotenoid ‘half-molecules’.

scholarly journals Cytochrome c Deficiency Differentially Affects the In Vivo Mitochondrial Electron Partitioning and Primary Metabolism Depending on the Photoperiod

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 444
Author(s):  
Igor Florez-Sarasa ◽  
Elina Welchen ◽  
Sofia Racca ◽  
Daniel H. Gonzalez ◽  
José G. Vallarino ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Tca Cycle ◽  
Day Length ◽  
Primary Metabolism ◽  
Stress Signaling ◽  
Alternative Pathways ◽  
Tca Cycle Intermediates ◽  
Growth Adaptation ◽  
Plant Respiration

Plant respiration provides metabolic flexibility under changing environmental conditions by modulating the activity of the nonphosphorylating alternative pathways from the mitochondrial electron transport chain, which bypass the main energy-producing components of the cytochrome oxidase pathway (COP). While adjustments in leaf primary metabolism induced by changes in day length are well studied, possible differences in the in vivo contribution of the COP and the alternative oxidase pathway (AOP) between different photoperiods remain unknown. In our study, in vivo electron partitioning between AOP and COP and expression analysis of respiratory components, photosynthesis, and the levels of primary metabolites were studied in leaves of wild-type (WT) plants and cytochrome c (CYTc) mutants, with reduced levels of COP components, under short- and long-day photoperiods. Our results clearly show that differences in AOP and COP in vivo activities between WT and cytc mutants depend on the photoperiod likely due to energy and stress signaling constraints. Parallel responses observed between in vivo respiratory activities, TCA cycle intermediates, amino acids, and stress signaling metabolites indicate the coordination of different pathways of primary metabolism to support growth adaptation under different photoperiods.

scholarly journals Anaerobic Conditions Induce Expression of Polysaccharide Intercellular Adhesin in Staphylococcus aureus and Staphylococcus epidermidis

2001 ◽  
Vol 69 (6) ◽  
pp. 4079-4085 ◽  
Author(s):  
Sarah E. Cramton ◽  
Martina Ulrich ◽  
Friedrich Götz ◽  
Gerd Döring
Keyword(s):  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Extracellular Polysaccharide ◽  
Growth Conditions ◽  
Anaerobic Conditions ◽  
Anaerobic Environment ◽  
Specific Mrna

ABSTRACT Products of the intercellular adhesion (ica) operon in Staphylococcus aureus and Staphylococcus epidermidis synthesize a linear β-1,6-linked glucosaminylglycan. This extracellular polysaccharide mediates bacterial cell-cell adhesion and is required for biofilm formation, which is thought to increase the virulence of both pathogens in association with prosthetic biomedical implants. The environmental signal(s) that triggers ica gene product and polysaccharide expression is unknown. Here we demonstrate that anaerobic in vitro growth conditions lead to increased polysaccharide expression in both S. aureus and S. epidermidis, although the regulation is less stringent inS. epidermidis. Anaerobiosis also dramatically stimulates ica-specific mRNA expression inica- and polysaccharide-positive strains of both S. aureus and S. epidermidis.These data suggest a mechanism whereby ica gene expression and polysaccharide production may act as a virulence factor in an anaerobic environment in vivo.

The Infection of the ventriculus of the adult honeybee by Nosema apis (Zander)

Parasitology ◽  
1955 ◽  
Vol 45 (1-2) ◽  
pp. 86-94 ◽  
Author(s):  
L. Bailey
Keyword(s):  
Calcium Phosphate ◽  
Central Region ◽  
Polar Filament ◽  
Rapid Development ◽  
Nosema Apis ◽  
Anaerobic Conditions ◽  
Free Living ◽  
Initial Infection ◽  
High Level

1. Spores of Nosema apis nearly all germinate within 30 min. after entering the ventriculus of the honeybee.2. The cause of germination in vivo remains unknown, but is probably not a change of osmotic pressure or pH and is probably not due to anaerobic conditions or an enzyme. The agent causing germination is probably unstable and is destroyed when removed from the bee.3. The anterior end of the ventriculus receives an initial heavy infection and the circumstantial evidence which this provides supports the theory that a free living ‘planont’ stage does not exist but that the parasite is injected directly into the host cell from the spore via the hollow polar filament.4. The central region of the ventriculus which contains many granules of calcium phosphate receives the lowest initial infection. It is considered possible that the granules inhibit the initial rapid development of the parasite by maintaining an unfavourably high level of pH until they are eventually dissolved by the slowly developing organism.

METABOLISM OF RAM TESTICULAR SPERMATOZOA IN THE PRESENCE OF TESTOSTERONE AND RELATED STEROIDS

1970 ◽  
Vol 65 (3) ◽  
pp. 565-576 ◽  
Author(s):  
J. K. Voglmayr ◽  
R. N. Murdoch ◽  
I. G. White
Keyword(s):  
Aerobic Glycolysis ◽  
Rete Testis ◽  
Glycolytic Metabolism ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Testicular Spermatozoa ◽  
Almost All ◽  
Oxidation Of Glucose

ABSTRACT The effects of testosterone* and related steroids on the oxidative and glycolytic metabolism of freshly collected ram testicular spermatozoa and of spermatozoa stored under air in rete testis fluid for 3 days at 3°C have been studied. When freshly collected testicular spermatozoa were incubated with glucose under aerobic conditions only a small proportion of the utilized glucose could be accounted for as lactate. The addition of a number of steroids, including testosterone, androstanedione, 5β-androstanedione, androsterone, epiandrosterone and 5β-androsterone, greatly increased aerobic glycolysis, the oxidation of the substrate and the proportion of the utilized substrate converted to lactic acid. After 3 days storage at 3°C, testicular spermatozoa respired at a greater rate than spermatozoa freshly collected from the testes. Although the stimulating effect of steroids on aerobic glycolysis increased after storage, they depressed rather than stimulated the oxidation of glucose by stored testicular spermatozoa. With the exception of androstanedione, which slightly stimulated glycolysis, storage of testicular spermatozoa for 3 days in the presence of steroids did not significantly influence their subsequent metabolism when washed free of the steroids. Both freshly collected and stored ram testicular spermatozoa displayed a marked Pasteur effect, and utilized more glucose and produced more lactate under anaerobic than under aerobic conditions. In the absence of oxygen the steroids did not stimulate glycolysis to any extent. However, epiandrosterone depressed the glycolysis of freshly collected spermatozoa under anaerobic conditions and after storage, 5β-androsterone had a similar effect. Androstanedione, 5β-androstanedione, epiandrosterone and 5β-androsterone were the most effective steroids in altering the metabolism of testicular spermatozoa and, under almost all conditions of incubation, depressed the synthesis of amino acids from glucose. The results suggest that the effects of testosterone and related steroids in vitro may depend on the age of the spermatozoa after their release from the Sertoli cells; the steroid effects may have important consequences in vivo in relation to sperm maturation.

scholarly journals Carotenoid Profiling of a Red Seaweed Pyropia yezoensis: Insights into Biosynthetic Pathways in the Order Bangiales

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 426 ◽  
Author(s):  
Jiro Koizumi ◽  
Naoki Takatani ◽  
Noritoki Kobayashi ◽  
Koji Mikami ◽  
Kazuo Miyashita ◽  
...  
Keyword(s):  
1H Nmr ◽  
Metabolic Pathways ◽  
Pyropia Yezoensis ◽  
Biosynthetic Pathways ◽  
Red Seaweed ◽  
Red Seaweeds ◽  
Natural Pigments ◽  
Photosynthetic Organisms ◽  
Metabolic Products ◽  
Β Carotene

Carotenoids are natural pigments that contribute to light harvesting and photo-protection in photosynthetic organisms. In this study, we analyzed the carotenoid profiles, including mono-hydroxy and epoxy-carotenoids, in the economically valuable red seaweed Pyropia yezoensis, to clarify the detailed biosynthetic and metabolic pathways in the order Bangiales. P. yezoensis contained lutein, zeaxanthin, α-carotene, and β-carotene, as major carotenoids in both the thallus and conchocelis stages. Monohydroxy intermediate carotenoids for the synthesis of lutein with an ε-ring from α-carotene, α-cryptoxanthin (β,ε-caroten-3’-ol), and zeinoxanthin (β,ε-caroten-3-ol) were identified. In addition, β-cryptoxanthin, an intermediate in zeaxanthin synthesis from β-carotene, was also detected. We also identified lutein-5,6-epoxide and antheraxanthin, which are metabolic products of epoxy conversion from lutein and zeaxanthin, respectively, by LC-MS and 1H-NMR. This is the first report of monohydroxy-carotenoids with an ε-ring and 5,6-epoxy-carotenoids in Bangiales. These results provide new insights into the biosynthetic and metabolic pathways of carotenoids in red seaweeds.

β-carotene as an inhibitor of benzo(a)pyrene and mitomycin C induced chromosomal breaks in the bone marrow of mice

1985 ◽  
Vol 27 (5) ◽  
pp. 598-602 ◽  
Author(s):  
A. S. Raj ◽  
Morris Katz
Keyword(s):  
Bone Marrow ◽  
Mitomycin C ◽  
Micronucleus Assay ◽  
Leafy Vegetables ◽  
Hybrid Strain ◽  
Green Leafy Vegetables ◽  
Polychromatic Erythrocytes ◽  
Chromosomal Breaks ◽  
Β Carotene

Female mice of hybrid strain B6C3F1, 8–10 weeks old, were fed on powdered food with or without β-carotene (100 mg/kg food). After 1 week of these diets, some of each group of mice were injected i.p. with either benzo(a)pyrene (150 mg/kg) in dimethyl sulfoxide, or mitomycin C (1 mg/kg) in distilled water. In the course of separate experiments, bone marrow samples were collected at various intervals after injection for analysis in the in vivo bone marrow micronucleus assay. At the time at which the maximum induction was observed, which coincided between experiments, the frequency of micronuclei induced by benzo(a)pyrene was reduced by 41–61% and that induced by mitomycin C was reduced by 44–71% in the presence of β-carotene. β-carotene is widely distributed in plant material such as carrots and green leafy vegetables and, as such, is a component of the human diet. Our results suggest that β-carotene provides significant protection against the genotoxicity of benzo(a)pyrene and mitomycin C.Key words: β-carotene, inhibitor, chromosomal breaks, micronucleated polychromatic erythrocytes.

In vitro antihemolytic effect, in vivo anti inflammatory and In vitro antioxidant activity of Anchusa azurea Mill

2021 ◽  
Vol 20 ◽  
Author(s):  
Boussoualim Naouel ◽  
Trabsa Hayat ◽  
Krache Imane ◽  
Ouhida Soraya ◽  
Arrar Lekhmissi ◽  
...  
Keyword(s):  
Methanolic Extract ◽  
Folk Medicine ◽  
Oxidative Degradation ◽  
Negative Control ◽  
Dependent Manner ◽  
Anti Inflammatory ◽  
Β Carotene ◽  
Inflammatory Effect

Background: Anchusa azurea Mill. (AA) is a medicinal plant largely used traditionally in folk medicine in Algeria, it is locally named: hamham. It is effective in the treatment of various diseases. Objectives: The aim of the present study is to determine the antioxidant, anti-inflammatory and anti-hemolytic effects of phenolic fractions from Anchusa azurea Mill. Methods: In this study, various extracts from Anchusa azurea Mill. (AA) using solvents with increasing polarity were prepared. The quantification of polyphenols and flavonoids was determined. The anti-radical activity of the different extracts was evaluated using DPPH and by measuring the inhibition of the oxidative degradation of β-carotene. The In vitro antihemolytic effect of the plant extracts is determined (CrE, ChE, AcE and AqE). For each extract, four concentrations were tested: 10.59, 21.18, 42.37, 84.74 µg/ml. Vitamin C is used as a standard. Free-radical attack was measured by measuring the HT50 (Half-Hemolysis Time). The anti-inflammatory effect using PMA on mice of the methanolic extract (CrE) was evaluated. Results: The quantification of polyphenols and flavonoids showed that ethyl acetate extract (AcE) contains a higher amount of polyphenols. However, chloroform extract (ChE) presents a higher amount of flavonoids. AcE showed an important scavenging activity using the DPPH radical (IC50= 68.35 µg/ml). The results showed that AcE also exhibited very great inhibition on the oxidation of β-carotene/linoleic acid (84.33%). All extracts increased the HT50 values (Half-Hemolysis Time) in a dose-dependent manner. The three highest concentrations (21.18, 42.37 and 84.74 µg / ml) of ChE caused a very significant delay (p ≤ 0.001) of hemolysis compared to the negative control and the positive control "VIT C". The anti-inflammatory effect using PMA on mice showed that the methanolic extract (CrE) of AA reduced the weight of the ear edema. Conclusions: This plant has a strong pharmacological power, which supports its traditional medicinal use.

Further evidence for the existence of cyclic and non-cyclic photophosphorylation in vivo by means of desaspidin and DCMU

1967 ◽  
Vol 22 (5) ◽  
pp. 537-540 ◽  
Author(s):  
W. Urbach ◽  
W. Simonis
Keyword(s):  
Antimycin A ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Cyclic Photophosphorylation ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

The effect of desaspidin and DCMU on photophosphorylation in intact cells under aerobic and anaerobic conditions has been studied. Desaspidin is mainly effective in N2 and inhibits under these conditions the DCMU-insensitive cyclic photophosphorylation in vivo like antimycin A. The inhibition of the phosphorylation in light by DCMU is stronger in N2 than in air which suggests a partial existence of oxydative phosphorylation during illumination.

scholarly journals β-carotene Suppresses Colon Cancer by Regulating M2 Macrophages and Tumor-associated Fibroblasts in Vitro and in Vivo (P02-015-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Yerin Kim ◽  
Na Youn Lee ◽  
Yoo Sun Kim ◽  
Yuri Kim
Keyword(s):  
Colon Cancer ◽  
Cancer Cells ◽  
Macrophage Polarization ◽  
M2 Macrophage ◽  
Invasion And Migration ◽  
And Migration ◽  
Emt Markers ◽  
Β Carotene

Abstract Objectives Tumor-associated macrophages (TAMs) and tumor-associated fibroblasts (TAFs) are consisted of tumor microenvironment (TME), which are involved in cancer progression and metastasis. Interactions within TME induce M2 macrophage phenotype, TAMs, and activate TAFs. β-carotene (BC) is a well-known antioxidant and showed protective effects on several diseases, including cancers. The object of this study is to investigate the anti-colorectal cancer (CRC) effects of BC by controlling macrophage polarization and fibroblast activation. Methods TAMs were induced by treating with phorbol-12-myristate-13-acetate (PMA) and interleukin-4 (IL-4) in U937 cells and TAFs were induced by treating with transforming growth factor-β1 (TGF-β1) in CCD-18Co cells. To understand the effect of TME on cancer cells, HCT116 colon cancer cells were co-cultured with TAM or TAF conditioned media. The effects of BC on the expressions of cancer stem cells (CSCs) markers, epithelial-mesenchymal transition (EMT) markers along with invasion and migration were investigated. To confirm these results, the azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colitis-associated CRC mice model was used. Results BC decreased M2 macrophage polarization with activating IL-6/STAT3 signaling pathways and suppressed the expressions of fibroblast activation markers and EMT markers. In addition, BC inhibited the expressions of TME-induced CSCs markers and EMT and suppressed cell invasion and migration. Furthermore, BC supplementation suppressed tumorigenesis and the expressions of M2 macrophage-associated markers, including CD206, Arg1, and Ym-1 as well as CSCs markers in vivo. Conclusions BC suppressed CRC by regulating TAMs and TAFs in vitro and in vivo, which indicated the potential therapeutic effects of BC on inflammatory diseases. Funding Sources This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education and Brain Korea 21 Plus.

scholarly journals A Mutant of Paracoccus denitrificans with Disrupted Genes Coding for Cytochrome c550 and Pseudoazurin Establishes These Two Proteins as the In Vivo Electron Donors to Cytochrome cd1 Nitrite Reductase

2003 ◽  
Vol 185 (21) ◽  
pp. 6308-6315 ◽  
Author(s):  
Isobel V. Pearson ◽  
M. Dudley Page ◽  
Rob J. M. van Spanning ◽  
Stuart J. Ferguson
Keyword(s):  
Nitrite Reductase ◽  
Paracoccus Denitrificans ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
Electron Mediator ◽  
Intact Cells ◽  
Cytochrome Cd1 ◽  
Membrane Bound ◽  
Electron Carriers

ABSTRACT In Paracoccus denitrificans, electrons pass from the membrane-bound cytochrome bc 1 complex to the periplasmic nitrite reductase, cytochrome cd 1. The periplasmic protein cytochrome c 550 has often been implicated in this electron transfer, but its absence, as a consequence of mutation, has previously been shown to result in almost no attenuation in the ability of the nitrite reductase to function in intact cells. Here, the hypothesis that cytochrome c 550 and pseudoazurin are alternative electron carriers from the cytochrome bc 1 complex to the nitrite reductase was tested by construction of mutants of P. denitrificans that are deficient in either pseudoazurin or both pseudoazurin and cytochrome c 550. The latter organism, but not the former (which is almost indistinguishable in this respect from the wild type), grows poorly under anaerobic conditions with nitrate as an added electron acceptor and accumulates nitrite in the medium. Growth under aerobic conditions with either succinate or methanol as the carbon source is not significantly affected in mutants lacking either pseudoazurin or cytochrome c 550 or both these proteins. We concluded that pseudoazurin and cytochrome c 550 are the alternative electron mediator proteins between the cytochrome bc 1 complex and the cytochrome cd 1-type nitrite reductase. We also concluded that expression of pseudoazurin is mainly controlled by the transcriptional activator FnrP.

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