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Z Kaniuga

Publications and source records attributed to Z Kaniuga.

At least 19 recordsLinked to original sources
PubMed1997

Galactolipase and chilling sensitivity of plants.

Galactolipase is a lipid acyl hydrolase (EC 3.1.1.26) acting predominantly on galactolipids which constitute up to 80% of total acyl lipids in chloroplast membrane. Evidence is presented on the involvement of this enzyme in plant response to chilling via degradation of membrane lipids and the increase of free fatty acids, associated with reduced oxygen evolution in the Hill reaction. The occurrence of two pools of fatty acids has been hypothesized. Analysis of numerous plant species showed higher galactolipase activity in the chilling-sensitive than in the chilling-resistant plants. Differences in the pH-dependence curve and in the response to detergents of galactolipases from these two groups of plants suggest heterogeneity of the enzyme. Referring to the hypothesis concerning the role of high melting-point fatty acids of phosphatidylglicerol molecular species in chilling sensitivity the data are presented against generalization of this hypothesis.

Carboxylic Ester Hydrolases↗
PubMed1993

Discrimination between chilling-sensitive and chilling-resistant plants based on measurements of free fatty acid accumulation and inactivation of oxygen evolution in aged chloroplasts.

The effect of aging of isolated chloroplasts of two chilling-sensitive (CS) and three chilling-resistant (CR) plants on the inactivation of oxygen evolution and accumulation of free fatty acids (FFA) was studied at 30 degrees C, pH 5.5 or 7.0, in the absence or presence of either sorbitol or NaCl. Considerable accumulation of FFA in aged chloroplasts of CS plants: bean and maize line F7-RpIII was accompanied by a marked inactivation of oxygen evolution. This relation was not, however, found in chloroplasts of CR species: pea, wheat and maize line EP1-RpI, in which the accumulation of FFA upon aging was very low whereas the decline of the rate of oxygen evolution was pronounced. In contrast to changes observed at pH 5.5, the inactivation of oxygen evolution in chloroplasts of CR species aged at pH 7.0 was dependent on the composition of the medium, especially in wheat chloroplasts. Thus, for the evaluation of chilling sensitivity based on the measurements of oxygen evolution activity solely, either aging of chloroplasts at pH 5.5 or possibly at pH 7.0 with NaCl included into the incubation medium may be recommended. It is concluded that determination of both the extent of FFA accumulation and inactivation of oxygen evolution in aged chloroplasts might be applied as chilling tolerance indexes.

Chloroplasts↗
PubMed1987

Comparison of galactolipase activity and free fatty acid levels in chloroplasts of chill-sensitive and chill-resistant plants.

Galactolipase activity in chloroplasts of several chill-resistant plants was found to be very low [0.02-0.13 mumol free fatty acid (FFA) liberated min-1 mg protein-1] or not detected. The same phenomenon was observed for soybean and members of the Cucurbitaceae such as cucumber, pumpkin, melon and squash. Since, following cold storage of cucumber leaves, the levels of monogalactosyl-diacylglycerol and digalactosyl-diacylglycerol in chloroplasts decrease while those of FFA accumulate it seems likely that in these typical chill-sensitive plants galactolipase is present but inactivated during isolation procedure. The low galactolipase activity in chloroplasts was accompanied by a relatively low FFA content ranging from 0.05 mumol to 0.30 mumol FFA mg chlorophyll (Chl)-1. However, both pea and horse bean chloroplasts (with low galactolipase activity) exhibit about 0.45 mumol FFA mg Chl-1. Elevated galactolipase activity was observed in chloroplasts of most chill-sensitive species (ranging from 0.31 mumol to 1.32 mumol FFA liberated min-1 mg protein-1) as well as in chloroplasts from broad bean, a member of a chill-resistant species (1.26 mumol FFA liberated min-1 mg protein-1). In addition in this latter group of plants FFA level in chloroplasts often did not fit the galactolipase activity. The results suggest that there exists a tendency for chilling tolerance of plants to decrease both galactolipase activity and FFA level. However, in some plant species with elevated galactolipase activity the chloroplast FFA level does not correlate with enzyme activity.

Carboxylic Ester Hydrolases↗
PubMed1985

Isolation and characterization of an iron-containing superoxide dismutase from tomato leaves, Lycopersicon esculentum.

A cyanide-insensitive superoxide dismutase was purified from tomato leaves (Lycopersicon esculentum, Mill., var. Venture) to apparent homogeneity. The enzyme had twofold higher specific activity (about 4000 standard units) than ferric superoxide dismutases purified from Brassica campestris [Salin, M. L. and Bridges, S. M. (1980) Arch. Biochem. Biophys. 201, 369-374] and Nuphar luteum [Salin, M.L. and Bridges, S. M. (1982) Plant Physiol. 69, 161-165]. The protein had a relative molecular mass of about 42000 and was composed of two equal subunits noncovalently joined. It was negatively charged (pI = 4.6) and contained about 1.45 mol Fe/mol dimer and negligible amounts of Mn, Cu and Zn. Absorption spectrum and sensitivity to NaN3, H2O2 and temperature are also reminiscent of other ferric superoxide dismutases. Comparison of amino acid composition indicated, however, a closer relationship to the Mn-containing enzymes rather than to other Fe-containing superoxide dismutases. Two possible ways of Fe-containing superoxide dismutase acquisition by vascular plants were suggested.

Amino Acids↗
PubMed1981

Photosynthetic apparatus of chilling-sensitive plants. IX. The involvement of alpha-tocopherol in the electron transport chain and the anti-oxidizing system in chloroplasts of tomato leaves.

1. The role of tocopherols in tomato chloroplasts from fresh, cold and dark-stored as well as stored and illuminated leaves was studied. 2. The cold and dark storage of leaves results in a loss of chloroplast alpha- and gamma-tocopherols of about 30-40% accompanied by an increase in chloroplast delta-tocopherol of about 40%. On illumination of stored leaves, an elevation of alpha- and gamma-tocopherol level to about 110 and 95% of the control, respectively, occurs, whilst delta-tocopherol content is not affected. 3. Experiments performed with 2,2-diphenyl-1-picrylhydrazyl-treated chloroplasts show that only about 70% of total alpha-tocopherol is functionally active in the electron transport of Photosystem II between the diphenylcarbazide (DPC) donation site and the inhibition site of DBMIB. 4. A small amount of alpha-tocopherol quinone (about 10% of alpha-tocopherol content) is found in chloroplasts from fresh, fresh and illuminated as well as cold and dark-stored tomato leaves, whereas the illumination of the latter increases the chloroplast alpha-tocopherol quinone content 3-fold. Moreover, following the illumination of chloroplasts from cold and dark-stored as well as stored and illuminated leaves, the oxidation of exogenous alpha-tocopherol to alpha-tocopherol quinone is 2-fold faster then in chloroplasts from fresh leaves. 5. The primary product ('alpha-tocopheroxide') formed during the alpha-tocopherol oxidation by illuminated chloroplasts was identified as 8a-hydroxy-alpha-tocopheron. 6. Exogenous alpha-tocopherol inhibits the lipid photoperoxidation by about 40-50% in chloroplasts from all three kinds of tomato leaf. 7. The results seem to suggest that chloroplast alpha-tocopherol is involved in both electron transport of PS II and antioxidizing system of chloroplasts.

2,6-Dichloroindophenol↗
PubMed1980

Photosynthetic apparatus in chilling-sensitive plants. VII. Comparison of the effect of galactolipase treatment of chloroplasts and cold-dark storage of leaves on photosynthetic electron flow.

1. Both galactolipase treatment of tomato chloroplasts and the cold and dark storage of leaves induce a large degradation of chloroplast monogalactosyl diacylglycerol and digalactosyl diacylglycerol as well as an accumulatwon of free fatty acids accompanied by the inhibition of Hill reaction activity with water as electron donor. All these changes are reversed upon illumination of the leaves. 2. Inhibition of diphenylcarbazide (DPC) leads to dichlorophenolindophenol (DCIP) activity by free fatty acids released following galactolipase treatment of chloroplasts isolated from either fresh or cold and dark-stored and illuminated leaves is almost completely reversed by either bovine serum albumin or Mn2+, while that in chloroplasts from the cold and dark-stored leaves is reversed by bovine serum albumin and Mn2+ only up to about 60 and 25%, respectively. 3. Fatty acids released during the treatment of chloroplasts with galactolipase affect the electron transport mainly in the same site as exogenous unsaturated fatty acids do, while those released due to endogenous galactolipase activity appear to affect also in the region damaged by either Tris washing of chloroplasts or the cold and dark treatment of leaves. 4. The loss of manganese from chloroplasts (Kaniuga, Z., Zabek, J. and Sochanowicz, B. (1978) Planta 144, 49-56) seems to be the main reason of cold and dark-induced inactivation of Hill reaction activity in chloroplasts of chilling-sensitive plants, while both the degradation of galactolipids and the accumulation of fatty acids are of secondary importance.

Chloroplasts↗