Stimulation of the cyanide-resistant alternative respiratory pathway by oxygen in Acremonium chrysogenum correlates with the size of the intracellular peroxide pool

2003 ◽  
Vol 49 (3) ◽  
pp. 216-220 ◽  
Author(s):  
Levente Karaffa ◽  
Erzsébet Sándor ◽  
Erzsébet Fekete ◽  
József Kozma ◽  
Attila Szentirmai ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Respiratory Activity ◽  
Peroxyl Radical ◽  
Radical Scavenger ◽  
Acremonium Chrysogenum ◽  
Alternative Respiration ◽  
Respiratory Pathway ◽  
Submerged Cultures ◽  
Alternative Respiratory Pathway ◽  
The Relationship

The relationship between oxygen input and activity of the cyanide-resistant alternative respiration of submerged cultures of Acremonium crysogenum was investigated. The volumetric oxygen transfer coefficient of the respective cultures correlated positively within almost two ranges of magnitude with the size of the intracellular peroxide pool, which in turn, correlated with the activity of the cyanide-resistant alternative respiratory pathway. Increased aeration also stimulated the glucose uptake rate but had no effect on the total respiration rate or the growth rate. Addition of the lipid peroxyl radical scavenger DL-α-tocopherol to A. chrysogenum cultures decreased the rate of intracellular peroxide production as well as glucose uptake. An increase in the cyanide-resistant fraction of total respiration was observed, while growth and the total respiratory activity remained unchanged. We conclude that intracellular peroxides may stimulate the alternative respiration in A. chrysogenum.Key words: Acremonium chrysogenum, alternative respiration, oxygen, peroxide, Kla.

The Role of Cu in Respiration of Pea Plants and Heterotrophically Growing Scenedesmus Cells

1988 ◽  
Vol 43 (5-6) ◽  
pp. 438-442 ◽  
Author(s):  
Matilde Barón Ayala ◽  
Gerhard Sandmann
Keyword(s):  
Cytochrome Oxidase ◽  
Respiratory Activity ◽  
The Other ◽  
Nadh Oxidation ◽  
Alternative Respiration ◽  
Respiratory Pathway ◽  
Cu Deficiency ◽  
Alternative Respiratory Pathway

In Scenedesmus about half of NADH oxidation proceeds via a cyanide-sensitive and the other half via a cyanide-insensitive respiratory pathway. In contrast, respiration is completely cyanide sensitive in pea indicating that the alternative respiratory pathway is absent. Cu deficiency in pea plants and in heterotrophically grown Scenedesmus cells interferes with respiratory activity of mitochondria. In both organisms, the cyanide-sensitive NADH oxidation was strongly decreased during cultivation in low Cu media. Cu sensitivity was also observed for the alternative respiratory pathway in Scenedesmus. These results suggest that a Cu-containing component is involved in the alternative respiratory pathway. This is the main reason why alternative respiration cannot be regarded as a compensation for low cytochrome-oxidase activities during Cu starvation. The Cu dependency of the cyanide-sensitive respiration was located at the site of cytochrome oxidase. A strong coordination of the biosynthesis of the Cu-containing cytochrome-oxidase complex was evident. When the endogenous Cu pool was low, formation of cytochrome aa3, another component of cytochrome oxidase, was also decreased.

Analysis of the relationship between growth, cephalosporin C production, and fragmentation in Acremonium chrysogenum

2001 ◽  
Vol 47 (9) ◽  
pp. 801-806 ◽  
Author(s):  
Erzsébet Sándor ◽  
Attila Szentirmai ◽  
Gopal C Paul ◽  
Colin R Thomas ◽  
István Pócsi ◽  
...  
Keyword(s):  
Image Analysis ◽  
Cephalosporin C ◽  
Acremonium Chrysogenum ◽  
Fed Batch ◽  
Submerged Cultures ◽  
Batch Cultures ◽  
Chemostat Cultures ◽  
Fed Batch Fermentation ◽  
Cephalosporin C Production ◽  
The Relationship

Mycelial fragmentation in submerged cultures of the cephalosporin C (CPC) producing fungus Acremonium chrysogenum was characterized by image analysis. In both fed-batch and chemostat cultures, the proportion of mycelial clumps seemed to be the most sensitive morphological indicator of fragmentation. In a fed-batch fermentation culture, this declined from roughly 60% at inoculation to less than 10% after 43 h. Subsequent additions of glucose resulted in a sharp increase back to near the initial value, an increase that reversed itself a few hours after glucose exhaustion. Meanwhile CPC production continued to decline steadily. On the other hand, the addition of soybean oil enhanced CPC production, but had no significant effect on the morphology. Although it may sometimes appear that morphology and productivity are related in batch or fed-batch cultures, this study suggests that this is because both respond simultaneously to more fundamental physiological changes, dependent on the availability of carbon. In circumstances, such as supplementary carbon source addition, the relationship is lost. Chemostat cultures supported this belief, as CPC-production rates were hardly affected by the specific growth rate, but the morphology showed significant differences, i.e., lower dilution rates resulted in a lower proportion of clumps and in smaller clumps.Key words: image analysis, Acremonium chrysogenum, morphology, fragmentation, cephalosporin C.

scholarly journals Respiration in a New Tuber Crop, Apios americana

1995 ◽  
Vol 120 (4) ◽  
pp. 656-660 ◽  
Author(s):  
M.E. Musgrave ◽  
W.J. Blackmon
Keyword(s):  
Genetic Background ◽  
Alternative Pathway ◽  
Tissue Respiration ◽  
Alternative Respiration ◽  
Genetic Line ◽  
Respiratory Pathway ◽  
Breeding Lines ◽  
Apios Americana ◽  
Alternative Respiratory Pathway ◽  
Tuber Crop

The objective of this study was to investigate the respiratory pathways in the underground storage tissues (tubers, fleshy roots, and rhizomes) of Apios americana Medikus (apios). Freshly sliced tubers of experimental breeding lines expressed variable capacities for alternative respiration, depending on genetic background, although the alternative respiratory pathway was not engaged in any of the apios tissues tested. The capacity of the alternative pathway present upon slicing was consistent with genetic line over the 5 years of the study. Respiration patterns of tubers and fleshy roots were comparable within a genetic line; however, substantial differences were found in the respiration of the nonthickened sections of rhizomes compared with the storage tubers. Total respiration of stored rhizomes was high (up to 2.7 μl O2/g per rein) compared to that of tubers (up to 0.9 μl O2/g per min). Rhizome tissue respiration had a large capacity for alternative respiration (40%-60% of total respiration), while tuber tissue had 0% to 73% alternative respiration, depending on genetic source. Epidermal layers, obtained from tubers that lacked a capacity for alternative respiration after slicing, had alternative respiration rates comparable to those of rhizomes. Furthermore, the alternative pathway could be induced in these tubers through conventional aging techniques. Etiolated shoots and rhizomes growing from these tubers also had an alternative respiration capacity that was half of the total rate. These results demonstrate that, although the capacity for alternative respiration is present in tissues of apios, freshly sliced tubers may or may not exhibit this pathway depending on genetic background. This attribute maybe significant as apios undergoes further domestication.

Cloning and Analysis of the Alternative Oxidase Gene of Neurospora crassa

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Qiuhong Li ◽  
R Gary Ritzel ◽  
Lesley L T McLean ◽  
Lee McIntosh ◽  
Tak Ko ◽  
...  
Keyword(s):  
Neurospora Crassa ◽  
Alternative Oxidase ◽  
Electron Flow ◽  
Mitochondrial Protein ◽  
Transcriptional Level ◽  
Wild Type ◽  
Respiratory Pathway ◽  
Oxidase Gene ◽  
Alternative Respiratory Pathway ◽  
Cytochrome Pathway

Mitochondria of Neurospora crassa contain a cyanide-resistant alternative respiratory pathway in addition to the cytochrome pathway. The alternative oxidase is present only when electron flow through the cytochrome chain is restricted. Both genomic and cDNA copies for the alternative oxidase gene have been isolated and analyzed. The sequence of the predicted protein is homologous to that of other species. The mRNA for the alternative oxidase is scarce in wild-type cultures grown under normal conditions, but it is abundant in cultures grown in the presence of chloramphenicol, an inhibitor of mitochondrial protein synthesis, or in mutants deficient in mitochondrial cytochromes. Thus, induction of alternative oxidase appears to be at the transcriptional level. Restriction fragment length polymorphism mapping of the isolated gene demonstrated that it is located in a position corresponding to the aod-1 locus. Sequence analysis of mutant aod-1 alleles reveals mutations affecting the coding sequence of the alternative oxidase. The level of aod-1 mRNA in an aod-2 mutant strain that had been grown in the presence of chloramphenicol was reduced several fold relative to wild-type, supporting the hypothesis that the product of aod-2 is required for optimal expression of aod-1.

Arabidopsis mtHSC70-1 plays important roles in the establishment of COX-dependent respiration and redox homeostasis

2019 ◽  
Vol 70 (20) ◽  
pp. 5575-5590 ◽  
Author(s):  
Shan-Shan Wei ◽  
Wei-Tao Niu ◽  
Xiao-Ting Zhai ◽  
Wei-Qian Liang ◽  
Meng Xu ◽  
...  
Keyword(s):  
Alternative Oxidase ◽  
Redox Homeostasis ◽  
Superoxide Dismutase 1 ◽  
Respiratory Pathway ◽  
Cellular Processes ◽  
Growth Defects ◽  
Alternative Respiratory Pathway ◽  
Abnormal Mitochondria ◽  
Shock Proteins ◽  
Severe Growth

Abstract The 70 kDa heat shock proteins function as molecular chaperones and are involved in diverse cellular processes. However, the functions of the plant mitochondrial HSP70s (mtHSC70s) remain unclear. Severe growth defects were observed in the Arabidopsis thaliana mtHSC70-1 knockout lines, mthsc70-1a and mthsc70-1b. Conversely, the introduction of the mtHSC70-1 gene into the mthsc70-1a background fully reversed the phenotypes, indicating that mtHSC70-1 is essential for plant growth. The loss of mtHSC70-1 functions resulted in abnormal mitochondria and alterations to respiration because of an inhibition of the cytochrome c oxidase (COX) pathway and the activation of the alternative respiratory pathway. Defects in COX assembly were observed in the mtHSC70-1 knockout lines, leading to decreased COX activity. The mtHSC70-1 knockout plants have increased levels of reactive oxygen species (ROS). The introduction of the Mn-superoxide dismutase 1 (MSD1) or the catalase 1 (CAT1) gene into the mthsc70-1a plants decreased ROS levels, reduced the expression of alternative oxidase, and partially rescued growth. Taken together, our data suggest that mtHSC70-1 plays important roles in the establishment of COX-dependent respiration.

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