PMID- 12060295
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 1399-3054 (Electronic)
IS  - 0031-9317 (Linking)
VI  - 113
IP  - 2
DP  - 2001 Oct
TI  - Regulation of alternative oxidase activity during phosphate deficiency in bean 
      roots (Phaseolus vulgaris).
PG  - 185-192
AB  - Cyanide-resistant respiration was studied in mitochondria isolated from the roots 
      of bean plants (Phaseolus vulgaris L. cv. Zlota Saxa) grown hydroponically up to 
      16 days on a phosphate-sufficient (+P, control) or phosphate-deficient (-P) 
      medium. Western blotting indicated that the alternative oxidase (AOX) was present 
      only in its reduced (active) form, both in phosphate-sufficient and 
      phosphate-deficient roots, but in the latter, the amount of AOX protein was 
      greater. Addition of pyruvate to the isolation, washing and reaction media made 
      mitochondria from +P roots cyanide-insensitive, similar to mitochondria from -P 
      roots. The doubled activity of NAD-malic enzyme (NAD-ME) in -P compared with +P 
      root mitochondria may suggest increased pyruvate production in -P mitochondria. 
      Lower cytochrome c oxidase (COX) activity and no uncoupler effect on respiration 
      indicated limited cytochrome chain activity in -P mitochondria. In -P 
      mitochondria, the oxygen uptake decreased and the level of Q reduction increased 
      from 60 to 80%. With no pyruvate present (AOX not fully activated), inhibition of 
      the cytochrome pathway resulted in an increased level of the ratio of reduced 
      ubiquinone (Qr) to total ubiquinone (Qt) (Qr/Qt) in +P mitochondria, but did not 
      change Qr/Qt in -P mitochondria. When pyruvate was present, the kinetics for AOX 
      were similar in mitochondria from -P and +P roots. It is suggested that AOX 
      participation in -P respiration may provide an acclimation to phosphate 
      deficiency. Stabilization of the ubiquinone reduction level by AOX might prevent 
      the harmful effect of an increased formation of reactive oxygen species.
FAU - Juszczuk, Izabela M
AU  - Juszczuk IM
AD  - Institute of Experimental Plant Biology, University of Warsaw, Miecznikowa 1, 
      PL-02-096 Warsaw, Poland Department of Molecular Cell Physiology, Free 
      University, De Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands.
FAU - Wagner, Anneke M
AU  - Wagner AM
FAU - Rychter, Anna M
AU  - Rychter AM
LA  - eng
PT  - Journal Article
PL  - Denmark
TA  - Physiol Plant
JT  - Physiologia plantarum
JID - 1256322
EDAT- 2002/06/13 10:00
MHDA- 2002/06/13 10:01
CRDT- 2002/06/13 10:00
PHST- 2002/06/13 10:00 [pubmed]
PHST- 2002/06/13 10:01 [medline]
PHST- 2002/06/13 10:00 [entrez]
AID - 1130205 [pii]
AID - 10.1034/j.1399-3054.2001.1130205.x [doi]
PST - ppublish
SO  - Physiol Plant. 2001 Oct;113(2):185-192. doi: 10.1034/j.1399-3054.2001.1130205.x.