Effect of Succinic Acid-2,2-Dimethylhydrazide on Endogenous Auxin Level in Apple Shoots

Endogenous auxin levels in the shoots of apple cv. Ingrid Marie (red mutant) treated with SADH (succinic acid-2,2-dimethylhydrazide) were measured. SADH was applied in aqueous solution at 12.5, 25 or 50 mM concentrations in June, 3 weeks after flowering. The defoliated shoot tips were analysed just before SADH spray and 7, 15, 30 and 60 days after spraying. Similar treatments had been made in earlier years. When analysed before the treatment of the year started, shoot extracts of control plants contained higher auxin level than those shoots which were to receive SADH treatment, indicating a residual effect of SADH treatmens during previous years. There was almost no auxin activity in the shoots analysed after 7, 15 and 30 days of SADH treatment. The control plants maintained a high level of auxin activity during this period. However, after 60 days of treatment, shoots treated with 25 or 50 mM exhibited higher auxin activity than control shoots. There appears to be no relationship between the SADH concentration and reduction in auxin activity in the shoots at early stages after treatment.     

Ethylene Evolution Stimulated by Succimc Acid-2,2-Dimethylhydrazide in Apple Shoots

The rate of ethylene production in the shoot tips of the apple cultivar ‘Ingrid Marie’ (Red motant) after succinic acid-2,2-dimethylhydrazide (SADH) treatment was investigated. The shoots were treated with SADH at 12.5, 25 or 50 mM in the months of June, July and August. The samples were analysed 7,15, 30 and 60 days after SADH spray. Ethylene production was considerably higher in the SADH-treated shoots than in the untreated ones. Application of 12.5 or 25mMSADH late in June stimulated ethylene production 3-fold, while 50 mM produced a 5-fold increase in ethylene production 7 days after spraying. There was a continuous decrease in ethylene production at the subsequent samplings. In untreated control shoots there was a slight increase. However, even 60 days after spraying the shoots treated with 50 mM had higher ethylene production than the control shoots. The same relationship was found in the shoots treated in the months of July and August. A parallelism has been established between the rate of ethylene production and growth retardation, A residual effect of SADH treatment in earlier years was demonstrated and is discussed.     

A Protein Inhibitor of Polygalacturonase in Apple Fruits Treated with Aminoethoxyvinylglycine and Cobalt Chloride

Ethylene evolution changes were monitored during storage of apple fruits (Malus domestica Borkh., winter cultivar Mantuanskoe) treated with aminoethoxyvinylglycine and CoCl₂. The storage of fruits was shown to be accompanied by changes in the activity of a protein inhibitor of polygalacturonase (PIPG). This inhibitor has been previously isolated from apple fruit tissues. The protein inhibitor of polygalacturonase was also shown to inhibit the activity of an enzyme produced by certain nonpathogenic fungi. The role of PIPG in apple fruit resistance to these fungi is discussed.     

1-Aminocyclopropane-1-Carboxylic Acid Levels in Ripening Apple Fruits

1-Aminocyclopropane-1-carboxylic acid (ACC) in amino acid fractionsof apple fruits was assayed by chemical conversion to ethylene.The specificity of the assay was checked with other amino acids;homocysteine was the only naturally occurring compound foundto yield significant amounts of ethylene in the assay. Analysisof the thiol content of apples showed that homocysteine couldnot be a significant source of interference. Interference froman uncharacterized component of amino acid fractions was lessthan 20% of the ACC level in unripe fruit and insignificantin ripe fruit. Liquid chromatographic assay gave results inclose agreement with the standard assay. Higher apparent ACClevels were measured in unfractionated apple juice than in thestandard assay. Both of these methods and the liquid chromatographicassay were used on a number of apple samples during ripening.All three methods showed that ACC increased 30–40 foldwhereas ethylene production increased by a factor of 10⁴. Inindividual apples the ACC level increased about one day laterthan ethylene production. Key words: Apple fruit, 1-Aminocyclopropane-1-carboxylic acid, Analytical methods, Ethylene     

Succinic Acid Production with Actinobacillus succinogenes ZT-130 in the Presence of Succinic Acid

Glucose fermentation with Actinobacillus succinogenes was carried out at different initial concentrations of succinic acid (SA₀) to determine its effect on growth and on the production of succinic acid itself. The specific rates of biomass production, succinic, formic and acetic acids decreased with SA₀ (0–40 g/l). The partially dissociated form of succinic acid had a higher effect on cell growth and production of succinic acid as compared to the non-dissociated forms of the acids, a fact that has not been reported until now. Cell growth fitted the Jerusalimski model, and the Aiba–Shoda model was suitable for quantification of the inhibition for the production of succinic acid. The growth inhibition constants K _is and K _ip and their summatory were consistent with the experimental values obtained, i.e., 22 g/l for the produced acids and 38 g/l for total acids that were the limits at which the biomass formation ceased.     

Indolyl-3-acetic Acid and Ethylene Levels in Ripening Apple Fruits

Indolyl-3-acetic acid (IAA) levels in apple (Malus domesticaBorkh.) fruits were determined fluorimetrically after formationof 2-methylindolo--pyrone in purified extracts. The propertiesof the fluorescent products in apple samples were identicalwith those of authentic IAA. The assays were performed on samplesof cortex with or without peel from the varieties James Grieveand Worcester Pearmain during the last 50—70 d of theirdevelopment on the tree. At the same time the ethylene concentrationin the core cavity of the fruits was measured as a guide tothe progress of ripening. IAA concentration showed a 3—4-foldincrease prior to the rapid rise in ethylene concentration butfell to about its original level as this rise occurred. IAAwas also measured in the seeds of James Grieve apples, whereit rose to a peak concentration and declined before the peakobserved in the fleshy tissue of the fruit. IAA in the seedsincreased markedly after 15 d storage of the fruit harvested136 d after full bloom.     

Effect of Abscisic Acid on Sorbitol Uptake in Growing Apple Fruits

Levels of abscisic acid (ABA) in the fruit flesh of developingapples (cv. Golden Delicious) were measured by electron capturegas chromatography. ABA content of the tissue, calculated ona fresh weight basis, decreased at a constant rate from 200µg g^–1 in young fruit to 10 µg g^–1 inolder fruit and then increased when the ripening process commenced.On a whole fruit basis, the ABA level increased during the initialphase of fruit growth, remained constant during the linear growthphase and increased again when fruits started to ripen. During fruit development the ABA content correlated with therate of sorbitol uptake, when measured after discs of fruittissue were incubated in [¹⁴C]sorbitol. Sorbitol uptake washigh during the initial growth phase and declined at a constantrate during fruit development. ABA present in the incubation medium stimulated sorbitol uptakeinto fruit tissue at concentrations higher than 10^–8 M,whereas indolyl-3-acetic acid had no effect on uptake. When comparing sorbitol uptake in different zones of young fruit,it was found that uptake was higher in discs of outer fruitlayers than in discs from inner fruit zones. Key words: Pyrus malus, Apple, Abscisic acid, Sorbitol     

Activities of Indoleacetic Acid Oxidase and Peroxidase in Ripening Apple Delicious Fruits

Peroxidase was extracted from the apple (Delicious) fruit and the apple stalk during the various stages of ripening. Activities of peroxidase and IAA oxidase of fruits are different.The activities of peroxidase and IAA oxidase in the apple stalk are much higher than that in the apple fruits. Gel electrophoresis revealed that the number of isozymic bands of peroxidase in the stalk (7–9 bands) were more than that in the fruit (6 bands). It is inferred that peroxidase in apple stalk might play a more important role in IAA and some other inhibitors oxidized before then went into the fruits.     

苹果果实细胞质中依赖活体组织的ABA高亲和力特异结合蛋白

将苹果（Malus pumila L.cv.Starkrimon)果肉微粒体和细胞可溶组分在含有^3H-ABA的缓冲介质中分别温育,仅在细胞可溶组分中测到微弱的^3H-ABA结合活性。但是,如何将果肉组织圆片在^3H-ABA缓冲介质中直接温育,经制备亚细胞组分后直接测定,在细胞可溶组分中测到很高的^3H-ABA特异结合活性。果肉圆片用沸水预先热处理使细胞可溶组分中的^3H-ABA结合活性完全丧失,说明ABA结合依赖于组织的活体状态。药理实验证明了ABA结合位点的蛋白质性质,同时证明该蛋白的活性中心具有－SH和丝氨酸基因。ABA结合蛋白对ABA的结合具有可饱和性、可逆性和高亲和力。Scatchard作图证明存在2种ABA结合蛋白,一种具有较高的亲和力,其解离常数（Kd)为2.9mmol/L,另一种亲和力相对较低,其Kd值为71.4nmol/L。用ABA结构相似物进行的竞争实验证明了ABA结合蛋白对配体结合的立体特异性。分析了ABA结合蛋白与ABA结合的时间曲线、pH和温度依赖性。本研究检测到的依赖活体组织的ABA结合蛋白可能是果实发育过程中介导ABA信号的受体。     

Bruise and Pressure Injury in Apple Fruits

The degree of injury in a freshly bruised region can be quantitativelymeasured by means of the resistance ratio (low-frequency resistance/high-frequencyresistance), since this ratio decreases progressively and significantlywith increased severity of bruising. The decrease is attributedmainly to mechanical injury of cell membranes. In addition to the prompt decrease in resistance ratio in thebruised regions there is also a delayed decrease, attributedto delayed injury resulting from the toxic after-effects ofliberated sap. Slight but significant decreases in resistanceratio are found external to the bruised region and are attributedto the toxic effects of extruded sap.     

In Vivo Tissue-dependent Abscisic Acid Specific-binding Proteins with High Affinity in Cytosol of Developing Apple Fruits (in English)

The in vivo highly tissue-dependent abscisic acid (ABA) specific-binding sites localized in cytosol were identified and characterized in the flesh of developing apple ( Malus pumila L. cv. Starkrimon) fruits. ABA binding activity was scarcely detectable in the microsomes and the cytosolic fraction isolated from the freshly harvested fruits via an in vitro ABA binding incubation of the subcellular fractions. If, however, instead that the subcellular fractions were in vitro incubated in H-ABA binding medium, the flesh tissue discs were directly in vivo incubated in H-ABA binding medium, a high ABA binding activity to the cytosolic fraction isolated from these tissue discs was detected. The in vivo ABA binding capacity of the cytosolic fraction was lost if the tissue discs had been pretreated with boiling water, indicating that the ABA binding needs a living state of tissue. The in vivo tissue-dependent binding sites were shown to possess protein nature with both active serine residua and thiol-group of cysteine residua in their functional binding center. The ABA binding of the in vivo tissue-dependent ABA binding sites to the cytosolic fraction was shown to be saturable, reversible, and of high affinity. The scatchard plotting gave evidence of two different classes of ABA binding proteins, one with a higher affinity ( Kd =2.9 nmol/L) and the other with lower affinity ( Kd =71.4 nmol/L). Phaseic acid, 2- trans -4- trans -ABA or cis-trans -(－)-ABA had substantially no affinity to the binding proteins, indicating their stereo-specificity to bind physiologically active ABA. The time course, pH- and temperature-dependence of the in vivo tissue-dependent binding proteins were determined. It is hypothesized that the detected ABA-binding proteins may be putative ABA-receptors that mediate ABA signals during fruit development.     

产琥珀酸放线杆菌发酵生产琥珀酸的研究进展

近年来,因瘤胃微生物产琥珀酸放线杆菌Actinobacillus succinogenes具有高的琥珀酸产量,并能够利用多种碳源进行发酵等优点,在利用发酵法生产琥珀酸领域具有广泛的应用前景和商业化价值,因而其代谢途径和发酵工艺等基础研究成为国内外研发的热点。近年来,人们在产琥珀酸放线杆菌的代谢途径、琥珀酸发酵动力学模型、新型经济培养基以及高产菌株选育等方面的研究取得了很大进展,对研发琥珀酸发酵工艺、降低生产成本和节能减耗等具有重要的理论意义。     

Xylem, Phloem and Transpiration Flows in Developing Apple Fruits

Xylem, phloem and transpiration flows were measured in developingfruits of the apples Royal Gala and Cox's Orange Pippin at early,mid and late stages during their development. Fruit volume growthwas first computed from measurements of diameter made usinga system of sensitive displacement transducers. Xylem, phloemand transpiration flow components (of which fruit volume growthis the integral) were then separated using a scheme of treatmentswhich disabled one or other flow at a time. Changes observed during development in the patterns of the threeflows are in general agreement with expectations based on lessdirect observations (loc. cit. Ferguson and Watkins, 1989).Recognizing the distinctive mineral compositions of xylem andphloem streams, the changes also accommodate, and seem to explain,published observations of mineral accumulation in apple. Significant differences in the pattern of xylem and phloem flowwere observed between the varieties examined. These may explainvarietal differences in susceptibility to the mineral imbalancedisorder bitter-pit. Xylem flows were shown to reverse at times; that is they flowedfrom fruit to tree. This occurred particularly during periodsof high evaporative demand. Xylem reversal is of importanceto the overall water economy of a tree but may also have specialimportance to the mineral composition of the fruit. Key words: Mineral nutrition, bitter-pit, apple, xylem, phloem, transpiration, water balance     

琥珀酸发酵菌种研究进展

琥珀酸作为一种重要的化学中间体的潜力已经为人们所认识,而发酵法生产琥珀酸是使这一潜力变为经济上可行的最好方法之一。菌种在发酵法中占有非常重要的地位,是决定整个过程的关键。系统介绍了关于发酵法生产琥珀酸的菌种研究进展,并对各种菌株的发酵特点和问题做了分析,最后展望了菌种的发展方向。     

HPLC法测定九节菖蒲中琥珀酸含量

目的:建立九节菖蒲中琥珀酸含量的HPLC测定法.方法:采用Kromasil C18色谱柱(150 mm×4.6mm,5μm);甲醇-0.02mol/L KH2PO4缓冲液(7∶93)(pH 2.5)为流动相;流速0.5 mL/min;柱温为30℃;检测波长为214nm.结果:琥珀酸在4～48μg范围内具有良好的线性关系,平均加样回收率为99.15％.九节菖蒲样品中的琥珀酸含量,以干燥品计为0.200％～0.318％.结论:该方法可行,重复性好,可用于九节菖蒲中琥珀酸含量的测定.     

Succinic Acid Turnover and Propionate Production in the Bovine Rumen

High velocity constants for conversion of added succinate to propionate, together with estimations of pool size, showed that extracellular succinate is the major precursor of the propionate formed in the rumen. Some bacteria give off succinate as a final fermentation product which is decarboxylated by others to propionate.     

Ribonucleic Acid Synthesis in Bacteria Treated with Toluene

Escherichia coli and Bacillus megaterium rendered permeable to ribonucleoside triphosphates by toluene treatment retain the capacity to synthesize discrete ribonucleic acid species.