{'fraction_non_alphanumeric': 0.02434928631402183, 'fraction_numerical': 0.006717044500419815, 'mean_word_length': 5.340425531914893, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Chill-Induced Changes in the Activity and Abundance of the Vacuolar Proton-Pumping Pyrophosphatase from Mung Bean Hypocotyls

Changes in the properties of extractable vacuolar H+-pumping pyrophosphatase (V-PPase) and vacuolar ATPase activities in chilling-sensitive seedlings of mung bean (Vigna radiata) were investigated. Following chilling at 4[deg]C for 48 h, both hydrolytic and proton-pumping activities of the V-PPase increased 1.5- to 2-fold over controls and remained elevated even after 72 h at low temperatures. Vacuolar ATPase levels did not change significantly throughout the chilling regime. However a large increase in alcohol dehydrogenase activity during chilling suggests a shift toward fermentative metabolism, which can be expected to decrease ATPase activity in situ. Western blotting of vacuolar membrane-enriched fractions from control and treated plants has confirmed that the changes in V-PPase activity are mirrored by increases in the amount of pump protein. Results suggest a specific role for the V-PPase in protecting chill-sensitive plants from the injurious effects of low temperatures via the maintenance of the proton gradient across the vacuolar membrane.