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61.
A chemolithoautotrophic type of metabolism, which was hitherto unknown for purple nonsulfur bacteria, was demonstrated by growth experiments using Rhodopseudomonas capsulata Kb1 and Rhodopseudomonas acidophila 10050. These strains were able to grow in a mineral medium in the dark at the expense of H2, O2, and CO2. A minimum doubling time of 9 h was obtained for R. capsulata under an atmosphere containing less than 15% oxygen; higher oxygen concentrations suppressed autotrophic but not chemoorganotrophic growth. Oxygen sensitivity of chemoautotrophically growing cells of R. acidophila was even more pronounced, whereas cells growing chemotrophically on methanol almost tolerated the oxygen concentration of air. Highest oxygen sensitivity of growth of R. acidophila was observed with formate as substrate. The growth yield of cultures grown semiaerobically in the dark on methanol was 0.23 g dry cell material per g methanol consumed. 相似文献
62.
Mutants of Bacillus subtilis constitutive for L-leucine dehydrogenase synthesis were selected. Using these mutants we could determine two functional roles for the L-leucine dehydrogenase. This enzyme liberates ammonium ions from branched chain amino acids when supplied as the sole nitrogen source. Another function is to synthesize from L-isoleucine, L-leucine, and L-valine the branched chain -keto acids which are precursors of branched chain fatty acid biosynthesis. These results together with the inducibility of the enzyme suggest that the L-leucine dehydrogenase has primarily a catabolic rather than an anabolic function in the metabolism of Bacillus subtilis. 相似文献
63.
Anne Durand Fabien Chauveau Tae-Hee Cho Radu Bolbos Jean-Baptiste Langlois Laure Hermitte Marlène Wiart Yves Berthezène Norbert Nighoghossian 《PloS one》2012,7(11)
Injection of thrombin into the middle cerebral artery (MCA) of mice has been proposed as a new model of thromboembolic stroke. The present study used sequential multiparametric Magnetic Resonance Imaging (MRI), including Magnetic Resonance Angiography (MRA), Diffusion-Weighted Imaging (DWI) and Perfusion-Weighted Imaging (PWI), to document MCA occlusion, PWI-DWI mismatch, and lesion development. In the first experiment, complete MCA occlusion and reproducible hypoperfusion were obtained in 85% of animals during the first hour after stroke onset. In the second experiment, 80% of animals showed partial to complete reperfusion during a three-hour follow-up. Spontaneous reperfusion thus contributed to the variability in ischemic volume in this model. The study confirmed the value of the model for evaluating new thrombolytic treatments, but calls for extended MRI follow-up at the acute stage in therapeutic studies. 相似文献
64.
65.
Kalocayova Barbora Snurikova Denisa Vlkovicova Jana Navarova-Stara Veronika Michalikova Dominika Ujhazy Eduard Gasparova Zdenka Vrbjar Norbert 《Molecular and cellular biochemistry》2021,476(12):4323-4330
Molecular and Cellular Biochemistry - Previously it was shown that for reduction of anxiety and stress of experimental animals, preventive handling seems to be one of the most effective methods.... 相似文献
66.
Francová Kateřina Šumberová Kateřina Kučerová Andrea Šorf Michal Grill Stanislav Exler Norbert Vrba Jaroslav 《Wetlands Ecology and Management》2021,29(1):93-110
Wetlands Ecology and Management - Plants play an important role in fishpond littorals, but little is known about factors influencing their presence and growth patterns. We surveyed vegetation of... 相似文献
67.
Elyeza Bakaze Beloved Mensah Dzomeku Jens‐Norbert Wünsche 《The Annals of applied biology》2021,178(1):98-108
Each year 25–75% of banana and plantain yields are lost because of rhizome damages caused by banana weevil (Cosmopolites sordidus) in growing regions of sub‐Saharan Africa. However, the specific plant defence response of the rhizome tissue in relation to the C. sordidus attack is unknown. Consequently, in this study, we evaluated whether plant defence substances in the rhizome are correlated with the degree of larval damage and whether applications of methyl jasmonate (MJ) elicit a greater induction of the plant defence potential against C. sordidus. Moreover, we attempted to reveal cellular modifications in response to the root feeding herbivore through histochemical staining. The banana cultivars “Km5” and “Mbwazirume” with tolerance and susceptibility to C. sordidus, respectively, were used in a pot experiment to evaluate percent rhizome damage, leaf chlorophyll content, total phenolic content (TPC), antioxidant capacity and cell morphology in response to C. sordidus attack and/or MJ applications compared to untreated control plants. We found that C. sordidus‐induced rhizome damage was 30% in the susceptible cultivar but less than 5% in the tolerant cultivar. The percent rhizome damage was not related to leaf chlorophyll content but showed a significant negative linear relationship to both TPC and antioxidant capacity. Larvae feeding induced a considerably greater increase of polyphenolic defence compounds in Km5 than in Mbwazirume; however, this response was opposite in the MJ treatment, suggesting that the phytohormone induced the susceptible plant to invest more into the synthesis of defence chemicals that in turn lead to reduced C. sordidus damage. Tissue staining demonstrated a greater deposition of lignin and suberin in C. sordidus challenged rhizome, presumably to seal off healthy tissue with a physical barrier from continued pest attack. It is concluded that MJ induces polyphenolics in susceptible Mbwazirume banana that reduced C. sordidus damage. 相似文献
68.
Timothy A. Swearengin Eugene E. Fibuch Norbert W. Seidler 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):575-579
The mechanism of inhalation anesthesia remains to be fully elucidated. While certain neuronal membrane proteins are considered sites of action, cytosolic proteins may also be targets. We hypothesize that inhaled anesthetics may act via glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which has recently been shown to participate in neuronal inhibition. We examined the effects of sevoflurane, a halogenated ether anesthetic, on the catalytic and fluorescence properties of GAPDH. Initial rates of oxidoreductase activity decreased approximately 30% at saturating levels of sevoflurane. NADH-stimulated oxidoreductase activity (25 μM NADH; 0.8 mM NAD+) increased with sevoflurane. Sevoflurane quenched tryptophan fluorescence emission and increased polarization. Additionally, sevoflurane increased the susceptibility of GAPDH to thermal denaturation suggesting an effect on conformation. Our findings warrant further research on sevoflurane's effect on GAPDH and indicate that this approach may lead to delineation of a novel contribution to the mechanism of anesthesia. 相似文献
69.
Katrine A. Gorham Mads P. Sulbaek Andersen Simone Meinardi Ralph J. Delfino Norbert Staimer Thomas Tjoa 《Biomarkers》2013,18(1):17-25
The relationship of exhaled ethane and n-pentane to exhaled NO, carbonylated proteins, and indoor/outdoor atmospheric pollutants were examined in order to evaluate ethane and n-pentane as potential markers of airway inflammation and/or oxidative stress. Exhaled NO and carbonylated proteins were found to have no significant associations with either ethane (p = 0.96 and p = 0.81, respectively) or n-pentane (p = 0.44 and 0.28, respectively) when outliers were included. In the case where outliers were removed n-pentane was found to be inversely associated with carbonylated proteins. Exhaled hydrocarbons adjusted for indoor hydrocarbon concentrations were instead found to be positively associated with air pollutants (NO, NO2 and CO), suggesting pollutant exposure is driving exhaled hydrocarbon concentrations. Given these findings, ethane and n-pentane do not appear to be markers of airway inflammation or oxidative stress. 相似文献
70.
Nicole Tegtmeyer Francisco Rivas Traverso Manfred Rohde Omar A. Oyarzabal Norbert Lehn Wulf Schneider-Brachert Richard L. Ferrero James G. Fox Douglas E. Berg Steffen Backert 《PloS one》2013,8(8)
Colonization by Helicobacter species is commonly noted in many mammals. These infections often remain unrecognized, but can cause severe health complications or more subtle host immune perturbations. The aim of this study was to isolate and characterize putative novel Helicobacter spp. from Bengal tigers in Thailand. Morphological investigation (Gram-staining and electron microscopy) and genetic studies (16SrRNA, 23SrRNA, flagellin, urease and prophage gene analyses, RAPD DNA fingerprinting and restriction fragment polymorphisms) as well as Western blotting were used to characterize the isolated Helicobacters. Electron microscopy revealed spiral-shaped bacteria, which varied in length (2.5–6 µm) and contained up to four monopolar sheathed flagella. The 16SrRNA, 23SrRNA, sequencing and protein expression analyses identified novel H. acinonychis isolates closely related to H. pylori. These Asian isolates are genetically very similar to H. acinonychis strains of other big cats (cheetahs, lions, lion-tiger hybrid and other tigers) from North America and Europe, which is remarkable in the context of the great genetic diversity among worldwide H. pylori strains. We also found by immunoblotting that the Bengal tiger isolates express UreaseA/B, flagellin, BabA adhesin, neutrophil-activating protein NapA, HtrA protease, γ-glutamyl-transpeptidase GGT, Slt lytic transglycosylase and two DNA transfer relaxase orthologs that were known from H. pylori, but not the cag pathogenicity island, nor CagA, VacA, SabA, DupA or OipA proteins. These results give fresh insights into H. acinonychis genetics and the expression of potential pathogenicity-associated factors and their possible pathophysiological relevance in related gastric infections. 相似文献