scholarly journals Changes in Alternative Pathway and Mitochondrial Respiration in Avocado in Response to Elevated Carbon Dioxide Levels

1997 ◽  
Vol 122 (2) ◽  
pp. 245-252 ◽  
Author(s):  
Diana L. Lange ◽  
Adel A. Kader
Keyword(s):  
Mitochondrial Respiration ◽  
Alternative Oxidase ◽  
Alternative Pathway ◽  
Respiratory Control ◽  
Persea Americana ◽  
Isolated Mitochondria ◽  
Harvest Dates ◽  
Avocado Fruit ◽  
Carbon Dioxide Levels

Partially ripened avocado [Persea americana (Mill.) cv. Hass] fruit harvested in either June or Aug. 1994 were kept at 10 °C in air (21% O2), 20% CO2 (17% O2, balance N2), or 40% CO2 (13% O2, balance N2) for 7 to 12 days and then were transferred to air at 10 °C for 2 to 3 days. Mitochondrial respiration was stimulated in response to elevated CO2 treatments at 10 °C. A shift to alternative pathway (Alt) respiration occurred on day 4 in experiments using avocados from both harvest dates, with a return to initial levels in only the 20% CO2-treated fruit (June-harvested fruit after return to air). Elevated CO2 at 20 °C decreased the in vitro O2 consumption of isolated mitochondria compared to mitochondria kept in air. The Alt pathway contributed less to the total O2 uptake of CO2-treated mitochondria compared to mitochondria kept in air. The respiratory control ratios of the CO2-treated fruit and mitochondria were higher and lower, respectively, than the air controls. Induction of 33 to 37 kD proteins (corresponding to the size of the alternative oxidase proteins) occurred in avocados after 4 days in 40% CO2. These results indicate that elevated CO2 has various effects depending on concentration, duration and temperature of exposure, and mitochondrial function of avocado fruit, such as increased and altered respiratory oxidation and up-regulation of alternative oxidase proteins.

scholarly journals Mitochondrial Self-restoration as an Index to the Capacity of Avocado Fruit to Sustain Atmospheric Stress at Two Climacteric States

1995 ◽  
Vol 120 (4) ◽  
pp. 643-649 ◽  
Author(s):  
Takaya Moriguchi ◽  
Roger J. Romani
Keyword(s):  
Strong Association ◽  
Respiratory Control ◽  
Persea Americana ◽  
Direct Exposure ◽  
Avocado Fruit ◽  
Pathogen Suppression ◽  
Hass Avocado ◽  
Atmosphere Storage

A strong association is implicit between mitochondrial function and the energy demands of cells responding to stress. Yet, the dynamics of this organelle-cellular dependency have been difficult to resolve. This study examines a new diagnostic parameter namely, mitochondrial maintenance and self-restoration as exhibited by the course of respiratory functions (states 3 and 4 respiratory rates, respiratory control) of mitochoudria extracted during and after exposure of intact `Hass' avocado (Persea americana) fruit to different stress atmospheres: anoxia (100% N2) or high (25% and 75%) CO2 for varying durations. Comparisons are made with direct exposure of the mitochondria themselves to similar atmospheres. In general, exposure of the fruit to CO2 rich atmospheres enhanced the capacity of their mitochondria to restore energy-linked functions whereas anoxia caused irreparable damage. The physiological (climacteric) state of the fruit also affected the stress capacity of the mitochondria contained therein, anaerobiosis being more harmful to mitochondria in riper fruit. In contrast to their effects in vivo, in vitro anoxia appeared to sustain mitochondrial energy-linked functions, whereas high CO2 was clearly harmful. These and other observations are discussed in the context of mitochondrial self-restoration or homeostasis and its relevance to postharvest stress-atmosphere storage for purposes such as pathogen suppression or insect control.

Effects of ageing and salicylate on beetroot mitochondria

2000 ◽  
Vol 27 (5) ◽  
pp. 445
Author(s):  
Felicity Johnson Potter ◽  
Ellen Bennett ◽  
Joseph T. Wiskich
Keyword(s):  
Mitochondrial Respiration ◽  
Alternative Oxidase ◽  
Alternative Pathway ◽  
The Other ◽  
Tissue Slices ◽  
Fresh Tissue ◽  
Outer Membranes ◽  
Ageing Treatment ◽  
Specific Induction ◽  
Increased Activity

Root tissue slices of Beta vulgaris were aged by aerated mixing for 5 d in 0.1 mM CaSO4 solution with and without 0.5 mM salicylate (pH 7.0). Mitochondria, isolated from treated and fresh beetroot tissue, were investigated, and the activities of the NAD(P)H oxidising pathways of the mitochondrial inner and outer membranes, together with the activity of the alternative pathway, were measured. From these we determined which non-phosphorylating pathways of mitochondrial respiration were induced by the treatments. The presence of salicylate in the ageing treatment was shown to increase the activity of the alternative pathway as well as the level of alternative oxidase protein. This increase was above that seen in the ageing treatment alone. Investigation of the other non-phosphorylating pathways of mitochondrial respiration indicated that while they also increased during ageing, they were not specifically affected by salicylate treatment. The specific induction of the alternative pathway increased activity by almost 4-fold from the fresh tissue and 2-fold from the aged tissue rates.

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930 ◽  
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Abstract Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

scholarly journals Kinetic analysis of the mitochondrial quinol-oxidizing enzymes during development of thermogenesis in Arum maculatum L

1996 ◽  
Vol 317 (1) ◽  
pp. 313-319 ◽  
Author(s):  
Graeme R. LEACH ◽  
Klaas KRAB ◽  
David G. WHITEHOUSE ◽  
Anthony L. MOORE
Keyword(s):  
Respiratory Rate ◽  
Succinate Dehydrogenase ◽  
Oxidase Activity ◽  
Alternative Oxidase ◽  
Alternative Pathway ◽  
Respiratory Control ◽  
Stage Of Development ◽  
Activation Level ◽  
Cytochrome Pathway ◽  
Arum Maculatum

The dependence of the rate of oxygen uptake upon the ubiquinone (Q)-pool reduction level in mitochondria isolated during the development of thermogenesis of Arum maculatum spadices has been investigated. At the α-stage of development, the respiratory rate was linearly dependent upon the reduction level of the Q-pool (Qr) both under state-3 and -4 conditions. Progression through the β/γ to the Δ-stage resulted in a non-linear dependence of the state-4 rate on Qr. In the Δ-stage of development, both state-3 and -4 respiratory rates were linearly dependent upon Qr due to a shift in the engagement of the alternative oxidase to lower levels of Qr. Western blot analysis revealed that increased alternative oxidase activity could be correlated with expression of a 35 kDa protein. Respiratory control was only observed with mitochondria in the α-stage of development. At the β/γ-stage of development, the addition of ADP resulted in a significant oxidation of the Q-pool which was accompanied by a decrease in the respiratory rate. This was due either to decreased contribution of the alternative pathway to the overall respiratory rate under state 3 or by deactivation of succinate dehydrogenase activity by ADP. Cold-storage of the spadices at the β-stage of development led to increased activity of both the cytochrome pathway and succinate dehydrogenase, without any change in alternative oxidase activity. Results are discussed in terms of how changes in the activation level of the alternative oxidase and succinate dehydrogenase influence the activity and engagement of the quinol-oxidizing pathways during the development of thermogenesis in A. maculatum.

An evaluation of the effects of five buffers on respiratory parameters of isolated mitochondria

1968 ◽  
Vol 46 (1) ◽  
pp. 43-50 ◽  
Author(s):  
R. A. Stinson ◽  
Mary Spencer
Keyword(s):  
Cytochrome C ◽  
Respiration Rate ◽  
Mitochondrial Respiration ◽  
Phosphate Buffer ◽  
Respiratory Control ◽  
Isolated Mitochondria ◽  
Respiratory Parameters ◽  
Control Respiration ◽  
Ethanesulfonic Acid ◽  
Ph Range

Certain compounds, recently introduced as buffers for biological work in the pH range 6–8, were evaluated by measurement of their effects on mitochondrial respiration. Respiratory control, respiration rate, ADP/O ratio, and the effect of added cytochrome c were measured on bean cotyledon mitochondria, after isolation and incubation of the mitochondria in one of five buffers: phosphate, Tris, Tricine (N-tris(hydroxymethyl)methylglycine), TES (N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid), and HEPES (N-2-hydroxyethylpiperazine-N1-2-ethanesulfonic acid). In all parameters measured, except response to added cytochrome c, purified TES was found to be superior to all other buffers. HEPES was the best in prevention of leakage of cytochrome c from the mitochondria but in other respects was similar to Tricine. Phosphate buffer proved superior to Tricine only with respect to cytochrome c retention by the mitochondria. Tris was the poorest buffer in which to measure any of these parameters. Aging the mitochondria in the various buffers amplified the inadequacies of the buffers and served to show the superiority of purified TES.

scholarly journals Non-Chemical Treatments for the Pre- and Post-Harvest Elicitation of Defense Mechanisms in the Fungi–Avocado Pathosystem

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6819
Author(s):  
Juan Antonio Herrera-González ◽  
Silvia Bautista-Baños ◽  
Mario Serrano ◽  
Gianfranco Romanazzi ◽  
Porfirio Gutiérrez-Martínez
Keyword(s):  
Defense Mechanisms ◽  
Persea Americana ◽  
Postharvest Quality ◽  
Plant Tissues ◽  
Pathogenic Microorganisms ◽  
Chemical Treatments ◽  
Avocado Fruit ◽  
Important Disease

The greatest challenge for the avocado (Persea americana Miller) industry is to maintain the quality of the fruit to meet consumer requirements. Anthracnose is considered the most important disease in this industry, and it is caused by different species of the genus Colletotrichum, although other pathogens can be equally important. The defense mechanisms that fruit naturally uses can be triggered in response to the attack of pathogenic microorganisms and also by the application of exogenous elicitors in the form of GRAS compounds. The elicitors are recognized by receptors called PRRs, which are proteins located on the avocado fruit cell surface that have high affinity and specificity for PAMPs, MAMPs, and DAMPs. The activation of defense-signaling pathways depends on ethylene, salicylic, and jasmonic acids, and it occurs hours or days after PTI activation. These defense mechanisms aim to drive the pathogen to death. The application of essential oils, antagonists, volatile compounds, chitosan and silicon has been documented in vitro and on avocado fruit, showing some of them to have elicitor and fungicidal effects that are reflected in the postharvest quality of the fruit and a lower incidence of diseases. The main focus of these studies has been on anthracnose diseases. This review presents the most relevant advances in the use of natural compounds with antifungal and elicitor effects in plant tissues.

Mitochondrial protein expression in tomato fruit during on-vine ripening and cold storage

2002 ◽  
Vol 29 (7) ◽  
pp. 827 ◽  
Author(s):  
Ruth C. Holtzapffel ◽  
Patrick M. Finnegan ◽  
A. Harvey Millar ◽  
Murray R. Badger ◽  
David A. Day
Keyword(s):  
Electron Transport ◽  
Alternative Oxidase ◽  
Uncoupling Protein ◽  
Tricarboxylic Acid Cycle ◽  
Tomato Fruit ◽  
Expression Patterns ◽  
Mitochondrial Protein ◽  
Respiratory Control ◽  
Isolated Mitochondria ◽  
Plant Uncoupling Protein

We have investigated the activity and abundance of a number of respiratory chain components in ripening and cold-treated tomato fruits (Lycopersicon esculentum L. Mill cvv. Moneymaker and Sweetie). Expression of the alternative oxidase (AOX) protein increased dramatically in both situations. Levels of the plant uncoupling protein (UCP) initially fell, but increased substantially in the later stages of ripening. In contrast, ATP synthase subunits and the COXII subunit of cytochrome oxidase decreased during ripening and increased slightly in response to cold stress. Other proteins involved in electron transport, tricarboxylic acid cycle function, chaperonin function, and membrane transport were also studied. These showed varying degrees of enhanced and depressed expression patterns. There were modest changes in whole fruit respiratory activities, and electron transport capacity of isolated mitochondria in response to these stimuli. However, respiratory control by ADP in the isolated mitochondria decreased as AOX capacity and abundance increased, indicating that although total respiration rates changed little, flux between the coupled and uncoupled pathways altered. The changes observed in AOX and UCP accumulation in tomato fruit that were vine-ripened were significantly different from post-harvest ripening patterns previously reported. The altered protein profiles are discussed in the context of on- and off-vine ripening and the potentially different roles of uncoupled respiration in each situation.

scholarly journals PHYTOCHEMICAL SCREENING AND IN VITRO ANTIOXIDANT AND ANTI-DIABETIC POTENTIALS OF PERSEA AMERICANA MILL. (LAURACEAE) FRUIT EXTRACT

2018 ◽  
Author(s):  
Mahadeva Rao US
Keyword(s):  
Therapeutic Potential ◽  
Kinetic Studies ◽  
Inhibitory Effect ◽  
Persea Americana ◽  
Phytochemical Screening ◽  
Fruit Extract ◽  
Avocado Fruit ◽  
Percentage Yield ◽  
Hydrolyzing Enzymes

Diabetes mellitus (DM) is a metabolic disorder characterized by insulin resistance and pancreatic β-cell dysfunction and the management of blood glucose level is an important strategy in the control of the disease and complications associated with it. Therefore, components that cause uptake of glucose from the bloodstream and inhibitors of carbohydrate hydrolyzing enzymes can be useful in treatment of DM and medicinal plants are often used to achieve this aim. Avocado fruit is rich in phytochemicals necessary for treatment of DM. The purpose of this study was to investigate the inhibitory effect of Persea americana fruit extracts on α-amylase and α-glucosidase enzymes. The percentage yield, phytochemical screening (both qualitative and quantitative), in vitro antioxidant and anti-diabeticassays, and kinetic studies were performed with different solvent extracts of Avocado fruit pulp. Results: Avocado hadgreat and promising potential as pharmaceutical agent, particularly to be developed as anti-diabetic through the inhibition of α-glucosidase and α- amylase enzymes.  In vitro studies of the antioxidant activity of the fruit extract gaveanevidence and strong biochemical rationale of their therapeutic potential. The fruit extract of P. americana may play an important role in the development of nutraceuticals and also in the management of oxidative stress induced DM.

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