The cytochromes in microsomal fractions of germinating mung beans

Hendry, G. A. F.; Houghton, Jennifer D.; Jones, Owen

doi:10.1042/bj1940743

Cited by 44 publications

(30 citation statements)

References 23 publications

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“…a peak is observed at 549 nm that is attributable to a c-type Cyt. In light of previous studies of microsomal membranes isolated from legume seedlings (Hendry et al, 1981;Lü thje et al, 1997), it is most likely that b-and c-type Cyts observed in cowpea cotyledons are from plasma membrane oxidases. In I. glandulifera pollen, the difference spectra (Fig.…”

Section: In Situ Spectrophotometric Determination Of Redox States Of mentioning

confidence: 99%

“…The relations between redox status and metabolic functions of Cyts have been extensively characterized in seeds by spectrophotometry of isolated mitochondria (Lance and Bonner, 1968;Wilson and Bonner, 1971;Ikuma, 1972;Sowa et al, 1993) and isolated microsomal membranes (Hendry et al, 1981;Lü thje et al, 1997). Extraction of mitochondria from dry tissues often leads to loss of structural and functional integrity (Hoekstra and van Roekel, 1983) or, at best, gives a low yield of intact material (Attucci et al, 1991).…”

Section: Desiccation Induces the Reduction Of Mitochondrial Cyts In Amentioning

confidence: 99%

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The Responses of Cytochrome Redox State and Energy Metabolism to Dehydration Support a Role for Cytoplasmic Viscosity in Desiccation Tolerance

Leprince

Hoekstra

1998

Plant Physiology

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To characterize the depression of metabolism in anhydrobiotes, the redox state of cytochromes and energy metabolism were studied during dehydration of soaked cowpea (Vigna unguiculata) cotyledons and pollens of Typha latifolia and Impatiens glandulifera. Between water contents (WC) of 1.0 and 0.6 g H 2 O/g dry weight (g/g), viscosity as measured by electron spin resonance spectroscopy increased from 0.15 to 0.27 poise. This initial water loss was accompanied by a 50% decrease in respiration rates, whereas the adenylate energy charge remained constant at 0.8, and cytochrome c oxidase (COX) remained fully oxidized. From WC of 0.6 to 0.2 g/g, viscosity increased exponentially. The adenylate energy charge declined to 0.4 in seeds and 0.2 in pollen, whereas COX became progressively reduced. At WC of less than 0.2 g/g, COX remained fully reduced, whereas respiration ceased. When dried under N 2 , COX remained 63% reduced in cotyledons until WC was 0.7 g/g and was fully reduced at 0.2 g/g. During drying under pure O 2 , the pattern of COX reduction was similar to that of air-dried tissues, although the maximum reduction was 70% in dried tissues. Thus, at WC of less than 0.6 g/g, the reduction of COX probably originates from a decreased O 2 availability as a result of the increased viscosity and impeded diffusion. We suggest that viscosity is a valuable parameter to characterize the relation between desiccation and decrease in metabolism. The implications for desiccation tolerance are discussed.

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Section: In Situ Spectrophotometric Determination Of Redox States Of mentioning

confidence: 99%

Section: Desiccation Induces the Reduction Of Mitochondrial Cyts In Amentioning

confidence: 99%

The Responses of Cytochrome Redox State and Energy Metabolism to Dehydration Support a Role for Cytoplasmic Viscosity in Desiccation Tolerance

Leprince

Hoekstra

1998

Plant Physiology

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“…There are no reports of cytochrome P-450 in seeds, but many reports of cytochrome P-450 in young seedlings. The daily development of cytochrome P-450 in germinating mung bean, has been recorded (Hendry, Houghton & Jones, 1981a). Figure 1 shows the appearance of cytochrome P-450 within 24 h of radical eruption of the testa following germination.…”

Section: Introductionmentioning

confidence: 99%

Why Do Plants Have Cytochrome P‐450? Detoxification Versus Defence

Hendry

1986

New Phytologist

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SUMMARYEvidence is presented which suggests that cytochrome P-450, in plants, probably functions as in all other eukaryotic organisms, principally as a detoxification mechanism. In plants this function is largely suppressed during tissue maturation coinciding with cell vacuolation. The consequential accumulation and isolation of potential toxins within vacuoles provides higher plants with an anti-herbivore defence of evolutionary significance.

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“…Initial attempts to correlate light-mediated Cyt reduction with other plasma membrane redox reactions have also been presented (3). Descriptions of plant Cyt have been almost exclusively based on crude membrane homogenates (12,13,26 Nitrate-sensitive ATPase (100 mM KN03) (22) was used as tonoplast marker. All ATPase activities were measured at pH 6.5 and in the presence of 100 Mm ammonium molybdate to inhibit nonspecific phosphatase activities (2).…”

mentioning

confidence: 99%

b-Type Cytochromes in Higher Plant Plasma Membranes

Asard¹,

Venken²,

Caubergs³

et al. 1989

Plant Physiol.

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The composition and characteristics of b-type cytochromes from higher plant plasma membranes, purified using aqueous two-phase partitioning, were investigated. At least three different cytochromes were identified by their wavelength maxima and redox midpoint potentials (Eo'). Cytochrome b-560.7 (Eo' from +110 to +160 millivolts) was present in zucchini (Cucurbita pepo) hypocotyls and bean (Phaseolus vulgaris L.) hooks, although in different concentrations. The main component in cauliflower (Brassica oleracea L.) inflorescences (cytochrome b-558.8) is probably functionally similar to this cytochrome. The plasma membrane generally contains two to three cytochrome species. However, the occurrence and concentrations were species dependent. The high potential cytochrome can be reduced by ascorbate but not NADH, and may be involved in blue light perception.

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The cytochromes in microsomal fractions of germinating mung beans

Cited by 44 publications

References 23 publications

The Responses of Cytochrome Redox State and Energy Metabolism to Dehydration Support a Role for Cytoplasmic Viscosity in Desiccation Tolerance

The Responses of Cytochrome Redox State and Energy Metabolism to Dehydration Support a Role for Cytoplasmic Viscosity in Desiccation Tolerance

Why Do Plants Have Cytochrome P‐450? Detoxification Versus Defence

b-Type Cytochromes in Higher Plant Plasma Membranes

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