Lipid mobilization, gluconeogenesis and ageing-related processes in dormant walnut kernels during moist chilling and warm incubation

2009 ◽  
Vol 19 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Tahereh Nezamdoost ◽  
Fatemeh Tamaskani ◽  
Ahmad Abdolzadeh ◽  
Hamid Reza Sadeghipour

AbstractTo understand the beneficial effects of cold conditions during the alleviation of dormancy of walnut (Juglans regiaL.), lipid mobilization, gluconeogenesis and changes related to ageing were compared in dormant kernels incubated in the cold and under deteriorating warm conditions. Stratifying kernels at 5°C for 30 d enhanced their germination capacity, whereas warm-incubated (27°C) kernels turned rancid after 20 d and had reduced germination. Kernel imbibition was sufficient to bring about lipid mobilization, irrespective of temperature of incubation. Although imbibed kernels displayed high isocitrate lyase activity, starch and soluble sugar accumulation occurred only under cold conditions. Deteriorative 64 kDa fatty acyl-ester hydrolase activity declined in cold-stratified kernels. Cold treatment also led to reduced lipid peroxidation and hydrogen peroxide in kernels. The activity of NADP+-isocitrate dehydrogenase, an NADPH-generating enzyme, declined in warm-incubated kernels. Thus, warm-incubated kernels undergo ageing associated with oxidative stress, but there are beneficial effects of cold stratification in preventing deteriorative ageing-related processes. Imbibition is sufficient to allow lipid mobilization to occur in dormant walnut kernels, although cold stratification accompanied by gluconeogenesis is essential for kernel germination.

2018 ◽  
Vol 45 (10) ◽  
pp. 1009 ◽  
Author(s):  
Yuanqin Zhao ◽  
Yanchun Ma ◽  
Qiang Li ◽  
Yang Yang ◽  
Jianrong Guo ◽  
...  

Utilisation of stored lipids plays an important role in germination of oil seeds. In the present study, key enzyme activity (lipase, isocitrate lyase and malate synthase) in lipid utilisation was determined during germination in dimorphic seeds of euhalophyte Suaeda salsa (L.) Pall. The results revealed that the percentage of germination were highest in intertidal brown seeds, followed by inland brown seeds and then inland black seeds moistened with 0 and 300 mM NaCl during early seed germination. The same trend was found in the activity of three enzymes and soluble sugar content when seeds were moistened with 0 and 300 mM NaCl for 3 h. Salinity reduced the activity of three enzymes in inland brown and black seeds in the initial 3 h, except that salinity had no adverse effect on isocitrate lyase activity of brown seeds. Salinity had no adverse effect on three enzymes in inland brown and black seeds in the initial 30 h, except that it decreased malate synthase activity of black seeds. Salinity had no effect on three enzymes in intertidal brown seeds in the initial 3 h and 30 h. In conclusion, high activity of these enzymes in brown seeds may play an important role in utilisation of stored lipids during their rapid seed germination.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1328
Author(s):  
Danielle Le Lievre ◽  
Rachelle Anderson ◽  
Helen Boldingh ◽  
Janine Cooney ◽  
Richard Seelye ◽  
...  

Consumer acceptance of fruit is determined by size, flavour and ripeness. In this study we investigated how altering the carbohydrate supply to Actinidia chinensis var. chinensis ‘Zesy002′ kiwifruit altered the balance between growth and accumulation of metabolites. Canes were phloem girdled and fruit thinned to a leaf-to-fruit ratio (L:F) of either 2 (Low carbohydrate) or 6 (High carbohydrate) at either 38 (Early) or 86 (Late) days after anthesis (DAA) and compared with ungirdled control canes with a L:F of 3. Fruit growth, metabolite accumulation, cytokinin concentrations and maturation were monitored and the sensory attributes of ripe fruit were assessed. The final weight of Early-High and Late-High carbohydrate fruit was 38% and 16% greater compared with control fruit. High carbohydrate fruit had increased starch,soluble sugar and cytokinin concentrations and fruit began to mature earlier and those with a Low carbohydrate had decreased concentrations and matured later compared with control fruit. Control fruit were described by consumers as more acidic and under-ripe compared with those from Early-High carbohydrate canes, but as sweeter than those from Low carbohydrate canes. This study showed that carbohydrate supply can have a major impact on the growth, sugar accumulation and maturity of ‘Zesy002′ fruit sinks.


1983 ◽  
Vol 66 (6) ◽  
pp. 1232-1236 ◽  
Author(s):  
M.C. Albizzatti de Rivadeneira ◽  
M.C. Manca de Nadra ◽  
A.A. Pesce de Ruiz Holgado ◽  
G. Oliver

1978 ◽  
Vol 24 (2) ◽  
pp. 149-153 ◽  
Author(s):  
T. M. Lakshmi ◽  
Robert B. Helling

Levels of several intermediary metabolites were measured in cells grown in acetate medium in order to test the hypothesis that the glyoxylate cycle is repressed by phosphoenolpyruvate (PEP). Wild-type cells had less PEP than either isocitrate dehydrogenase – deficient cells (which had greater isocitrate lyase activity than the wild type) or isocitrate dehydrogenase – deficient, citrate synthase – deficient cells (which are poorly inducible). Thus induction of the glyoxylate cycle is more complicated than a simple function of PEP concentration. No correlation between enzyme activity and the level of oxaloacetate, pyruvate, or citrate was found either. Citrate was synthesized in citrate synthase – deficient mutants, possibly via citrate lyase.


2020 ◽  
Vol 69 (1-2) ◽  
pp. 5-11
Author(s):  
Dijana Kulačanin ◽  
Sandra Bijelić ◽  
Jovana Šućur ◽  
Borivoje Bogdanović ◽  
Sezai Ercisli ◽  
...  

SummaryThe beneficial effects of walnuts and walnut products on human health, due primarily to their rich polyphenolic content, have been appreciated as an empirical fact for centuries. The purpose of this study is to determine the polyphenolic contents of liqueurs made from the walnut selections ‘Rasna’ and ‘Sava’ and the walnut cultivar ‘Šampion’ (all harvested at three different times), as well as the polyphenolic contents of their green husks. The walnut liqueurs were prepared according to two traditional recipes using young walnut fruits. The highest antioxidant capacity was recorded in the liqueur made from the ‘Rasna’ walnut selection (89.94%), whereas the highest contents of phenols (83.28 mg GAE/g FW), flavonoids (0.83 mg QE/g FW) and proanthocyanidins were found in the liqueur made from the ‘Šampion’ cultivar (14.75 mg CE/g FW). The youngest ‘Rasna’ walnuts, harvested at the first experimental time point, exhibited the highest phenolic and tannin contents, whereas the highest flavonoid content was observed in the ‘Šampion’ cultivar. The biochemical results obtained indicate a decrease in the polyphenolic content of walnut fruits with their growth and development. Moreover, the polyphenolic profiles of the walnut liqueurs considered were found to be greatly affected by the method of preparation and the cultivar/selection of walnuts.


Weed Science ◽  
1970 ◽  
Vol 18 (5) ◽  
pp. 565-571
Author(s):  
J. A. Mulliken ◽  
C. A. Kust ◽  
L. E. Schrader

Endosperm dry weight, protein, and fat losses accompanied rapid radicle growth of velvetleaf (Abutilon theophrasti Medic.) between 12 and 36 hr of germination at 31 C. Cotyledonary reserves were mobilized after 36 hr. Isocitrate lyase activity sedimented with a particulate fraction in varying degrees, but maximal activity developed at times coincident with fat mobilization. Respiration of excised endosperms reached maximal rates shortly after radicle emergence. The actions of hydrogen cyanide, carbon monoxide, and 2,4-dinitrolphenol indicated that respiration of endosperms excised from imbibed and germinated seed was due to cytochrome oxidase activity, and was coupled to phosphorylation.


1970 ◽  
Vol 16 ◽  
pp. 95-99 ◽  
Author(s):  
Md Rezaul Karim ◽  
MMH Khan ◽  
Md Salim Uddin ◽  
NK Sana ◽  
F Nikkon ◽  
...  

Significant differences were found in sugar content and carbohydrate splitting enzyme activities in tubers of ten indigenous potato varieties at harvesting and after keeping at cold storage. The activities of invertase, amylase, β-galactosidase and cellulase in all varieties were found to be increased by 2-12, 1.2-4, 1.9-4.5, and 1.1-3.7 folds, respectively from harvesting to cold stored potatoes. The amount of starch and sucrose were found to be decreased by 1.15-2.8 and 1.02-1.4 folds, respectively from harvesting to cold stored in all varieties. Total soluble sugar and reducing sugar contents in potatoes were increased by 1.02-1.4 and 4-11 folds, respectively from harvesting to cold stored in all varieties of potatoes. The amount of reducing sugar increased in cold stored potatoes due to the increased activities of carbohydrate splitting enzymes. Key words: Potatoes, Indigenous, Carbohydrate splitting enzymes, Sugars. DOI:10.3329/jbs.v16i0.3748 J. bio-sci. 16: 95-99, 2008


2014 ◽  
Vol 50 (No. 1) ◽  
pp. 43-51 ◽  
Author(s):  
R. Kabiri ◽  
F. Nasibi ◽  
H. Farahbakhsh

To study the effect of salicylic acid on photosynthetic pigments (chlorophyll a, b, total chlorophyll, and carotenoids), polyphenol compounds, anthocyanin, flavonoids, phenylalanine ammonia-lyase activity, malondialdehyde, lipoxygenase activity, electrolyte leakage, relative water content, soluble sugar contents, and protein content of black cumin (Nigella sativa) under drought stress in hydroponic culture, an experiment was conducted as a completely randomised design in a factorial arrangement with three replicates. Experimental treatments included salicylic acid at three levels (0, 5, and 10µM) and drought stress (induced by polyethylene glycol 6000) at four levels (0, –0.2, –0.4, and –0.6 MPa). Results showed that salicylic acid application through the root medium increased drought tolerance of black cumin seedlings. Plants pre-treated with salicylic acid exhibited slight injury symptoms whereas those not pre-treated with salicylic acid had moderate damage and lost considerable portions of their foliage. In conclusion, salicylic acid could protect the Nigella plant against drought stress through increasing of all the mentioned traits, and 10µM salicylic acid was the most effective level under both conditions.


2000 ◽  
Vol 182 (24) ◽  
pp. 7007-7013 ◽  
Author(s):  
Marijke A. H. Luttik ◽  
Peter Kötter ◽  
Florian A. Salomons ◽  
Ida J. van der Klei ◽  
Johannes P. van Dijken ◽  
...  

ABSTRACT The Saccharomyces cerevisiae ICL1 gene encodes isocitrate lyase, an essential enzyme for growth on ethanol and acetate. Previous studies have demonstrated that the highly homologousICL2 gene (YPR006c) is transcribed during the growth of wild-type cells on ethanol. However, even when multiple copies are introduced, ICL2 cannot complement the growth defect oficl1 null mutants. It has therefore been suggested thatICL2 encodes a nonsense mRNA or nonfunctional protein. In the methylcitrate cycle of propionyl-coenzyme A metabolism, 2-methylisocitrate is converted to succinate and pyruvate, a reaction similar to that catalyzed by isocitrate lyase. To investigate whetherICL2 encodes a specific 2-methylisocitrate lyase, isocitrate lyase and 2-methylisocitrate lyase activities were assayed in cell extracts of wild-type S. cerevisiae and of isogenicicl1, icl2, and icl1 icl2 null mutants. Isocitrate lyase activity was absent in icl1 andicl1 icl2 null mutants, whereas in contrast, 2-methylisocitrate lyase activity was detected in the wild type and single icl mutants but not in the icl1 icl2mutant. This demonstrated that ICL2 encodes a specific 2-methylisocitrate lyase and that the ICL1-encoded isocitrate lyase exhibits a low but significant activity with 2-methylisocitrate. Subcellular fractionation studies and experiments with an ICL2-green fluorescent protein fusion demonstrated that theICL2-encoded 2-methylisocitrate lyase is located in the mitochondrial matrix. Similar to that of ICL1, transcription of ICL2 is subject to glucose catabolite repression. In glucose-limited cultures, growth with threonine as a nitrogen source resulted in a ca. threefold induction ofICL2 mRNA levels and of 2-methylisocitrate lyase activity in cell extracts relative to cultures grown with ammonia as the nitrogen source. This is consistent with an involvement of the 2-methylcitrate cycle in threonine catabolism.


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