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The acetyl-CoA pathway of autotrophic growth 总被引:3,自引:0,他引:3
Abstract The most direct conceivable route for synthesis of multicarbon compounds from CO2 is to join two molecules of CO2 together to make a 2-carbon compound and then polymerize the 2-carbon compound or add CO2 successively to the 2-carbon compound to make multicarbon compounds. Recently, it has been demonstrated that the bacterium, Clostridium thermoaceticum , grows autotrophically by such a process. The mechanism involves the reduction of one molecule of CO2 to a methyl group and then its combination with a second molecule of CO2 and CoA to form acetyl-CoA. We have designated this autotrophic pathway the acetyl-CoA pathway [1]. Evidence is accumulating that this pathway is utilized by other bacteria that grow with CO2 and H2 as the source of carbon and energy. This group includes bacteria which, like C. thermoaceticum , produce acetate as a major end product and are called acetogens or acetogenic bacteria. It also includes the methane-producing bacteria and sulfate-reducing bacteria.
The purpose of this review is to examine critically the evidence that the acetyl-CoA pathway occurs in other bacteria by a mechanism that is the same or similar to that found in C. thermoaceticum . For this purpose, the mechanism of the acetyl-CoA pathway, as found in C. thermoaceticum , is described and hypothetical mechanisms for other organisms are presented based on the acetyl-CoA pathway of C. thermoaceticum . The available data have been reviewed to determine if the hypothetical schemes are in accord with presently known facts. We conclude that the formation of acetyl-CoA by other acetogens, the methanogens and sulphate-reducing bacteria occurs by a mechanism very similar to that of C. thermoaceticum . 相似文献
The purpose of this review is to examine critically the evidence that the acetyl-CoA pathway occurs in other bacteria by a mechanism that is the same or similar to that found in C. thermoaceticum . For this purpose, the mechanism of the acetyl-CoA pathway, as found in C. thermoaceticum , is described and hypothetical mechanisms for other organisms are presented based on the acetyl-CoA pathway of C. thermoaceticum . The available data have been reviewed to determine if the hypothetical schemes are in accord with presently known facts. We conclude that the formation of acetyl-CoA by other acetogens, the methanogens and sulphate-reducing bacteria occurs by a mechanism very similar to that of C. thermoaceticum . 相似文献
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Perlińska-Lenart U Orlowski J Laudy AE Zdebska E Palamarczyk G Kruszewska JS 《Applied and environmental microbiology》2006,72(12):7778-7784
Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increased amount of N-acetylglucosamine, suggesting an increase in chitin content. Calcofluor white staining followed by fluorescence microscopy indicated changes in chitin distribution. Moreover, we also observed a decreased concentration of mannose and alkali-soluble beta-(1,6) glucan. A comparison of protein secretion from protoplasts with that from mycelia showed that the cell wall created a barrier for secretion in the DPM1 transformants. We also discuss the relationships between the observed changes in the cell wall, increased protein glycosylation, and the greater secretory capacity of T. reesei strains expressing the yeast DPM1 gene. 相似文献
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Acinetobacter baumannii causes serious infections especially in immunocompromised and/or hospitalized patients. Several A. baumannii strains are multidrug resistant and infect wounds, bones, and the respiratory tract. Current studies are focused on finding new effective agents against A. baumannii. Phage therapy is a promising means to fight this bacterium and many studies on procuring and applying new phages against A. baumannii are currently being conducted. As shown in animal models, phages against multidrug-resistant A. baumannii may control bacterial infections caused by this pathogen and may be a real hope to solve this dangerous health problem. 相似文献
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Zalejska-Fiolka J Kasperczyk A Kasperczyk S Błaszczyk U Birkner E 《Biological trace element research》2007,120(1-3):195-204
Effect of garlic supplementation on blood antioxidant status, lipid peroxidation, and coronary plaque formation process was
investigated in oxidized oil-fed rabbits. Eighteen adult male mixed European rabbits were given a balanced diet (21 g% protein,
34 g% fat, 45 g% carbohydrate), which contained isocaloristic addition of nonoxidized or oxidized rapeseed oil in the presence
and absence of garlic. The experiment lasted 24 weeks. At the beginning and every 6 weeks, rabbits were weighed, and blood
was taken. To evaluate the antioxidant status of the rabbits, erythrocytes malondialdehyde (MDA) concentration, total superoxide
dismutase (t-SOD), and glutathione peroxidase (GPX) activations were determined. After the experiment was completed, aortas
were dissected for histological examinations. Changes in the contents of the above parameters and histological examinations
showed that oxidized rapeseed, oil administered to rabbits, caused the development of atherosclerotic changes and disturbed
antioxidant status. The addition of garlic in such diets inhibited atherosclerotic changes in the aorta wall, and it is related
to the homeostatic activity of antioxidative enzymes and lipid peroxidation. 相似文献
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Kawiak Anna Królicka Aleksandra Lojkowska Ewa 《Plant Cell, Tissue and Organ Culture》2003,75(2):175-178
An efficient protocol for the micropropagation of Drosera anglica, D. binata and D. cuneifolia is described. Proliferation was obtained from leaf segments and shoot tips, which served as initial explants. The regeneration capacity of explants was influenced by factors such as nutrient media, concentrations of growth regulators and the type of medium (liquid or solid). The highest number of plants regenerating from D. binata explants was obtained on the growth regulator-free Vacin and Went medium. In the case of D. anglica the highest proliferation rate was obtained on the Fast medium supplemented with 0.05 M 6-benzyladenine (BA) and 0.005 M -naphthaleneacetic acid (NAA), whereas for D. cuneifolia the optimal regeneration medium proved to be 1/2 MS with the growth regulator supplementation estimated at 0.2 M BA and 0.2 M NAA. Liquid media significantly increased the regeneration potential of D. anglica and D. binata explants. 相似文献
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