The Biosynthesis of (+)-Tartaric Acid in Pelargonium crispum

Metabolic conversion of l-galactono-1, 4-lactone and l-ascorbic acid to (+)-tartaric acid and oxalic acid has been studied in Pelargonium crispum, cv. Prince Rupert. Experiments with specifically labeled substrates suggest a path of conversion involving cleavage of l-ascorbic acid, or a metabolic product of l-ascorbic acid, between C₂ and C₃, such that oxalic acid arises from the two carbon fragment and (+)-tartaric acid from the four carbon fragment.     

Synthesis of l-(+)-Tartaric Acid from l-Ascorbic Acid via 5-Keto-d-Gluconic Acid in Grapes

5-Keto-l-idionic acid (5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid.     

Tartaric Acid Mediated Cr Hyperaccumulation and Biochemical alterations in seedlings of Hordeum vulgare L.

Journal of Plant Growth Regulation - The present study was done to evaluate the effects of tartaric acid (TA) amendment on physiology of Hordeum vulgare L. seedlings under Cr(VI) stress. Cr(VI) at...     

药用谷氨酸含量测定方法的改进

药用谷氨酸是具有生物活性的L-型谷氨酸。中国药典(1977年版)只对它的旋光度做了如下规定:(+)31.7～(+)32.3,而对其含量限度未做要求。据查英、美药典(1980年版)、日本药局方第十版对该药均无收载。因此我们做了一些工作。采用几种不同方法测定药用谷氨酸的含量,对凯氏定氮法、中和法、旋光法进行了比较。测定中以凯氏定氮法为准,计算回收率,并计算其均值、标准差及变异系数。实验结果表明,采用旋光法较好。回收率为100.003%,标准差为0.2525,变异系数为0.2525%。     

Stereoisomeric Characterization of Tartaric Acid Produced during l-Ascorbic Acid Metabolism in Plants

Labeled tartaric acids from Pelargonium crispum apices which had been fed l-ascorbic acid-6-(14)C and Vitis labrusca and Parthenocissus inserta tissues which had been fed l-ascorbic acid-1-(14)C were examined by chemical means to determine chiral configuration. In each instance, label was associated with (+)-tartaric acid.Similar experiments with labeled tartaric acid from P. crispum which had been labeled with d-glucose-1-(14)C or -6-(14)C led to the same result. No evidence was obtained for formation of labeled meso-tartaric acid in experiments described above. The recent suggestion of H. Ruffner and D. Rast (Z. Pflanzenphysiol. 73: 45-55, 1974) that conversion of l-ascorbic acid to tartaric acid in plants is a nonenzymatic process is re-examined in the light of present findings.     

EGTA和酒石酸对蓖麻Cd胁迫与积累的调控作用

通过盆栽试验研究了解毒剂酒石酸与螯合剂EGTA的单施与配施对强化蓖麻修复Cd污染土壤的作用,探讨重金属污染土壤植物修复中螯合剂与解毒剂配合使用的可行性。结果显示:(1)除酒石酸单施处理外,其余处理均可显著提高土壤中醋酸提取态Cd含量,增强土壤Cd的活性,并以酒石酸与EGTA配施的效果更显好,其土壤醋酸提取态Cd含量为对照的1.41~2.49倍。(2)EGTA能有效促进Cd从蓖麻根部向地上部的转移,但高剂量EGTA处理对蓖麻根系有明显的毒害作用;EGTA与酒石酸配合施能缓解Cd对植株的毒害作用,增大蓖麻生物量和Cd积累量,其地上部Cd积累量比对照增加4.56~8.32倍。(3)蓖麻叶片Cd含量、地上部积累总量以及土壤净化率随土壤醋酸提取态Cd含量的升高而增大,并且呈良好的线性递增关系。研究表明,酒石酸与EGTA配施可通过调控土壤Cd的植物可利用性和降低Cd的生理毒性来提高蓖麻对Cd的富集能力和对Cd污染土壤的修复效果。     

Isolation and Chemical Structure of New Oxidation Product of 5-Ketogluconic Acid,and a Hypothetical Pathway from Glucose to Tartaric Acid through this New Compound

In the course of study on the mechanism of the tartaric acid formation from 5-ketogluconic acid, a new intermediary substance with mauve color to Abdel-Akhel and Smith’s reagent was isolated from intact cell culture liquid. The chemical structure of this substance was determined as 1,2-dihydroxyethyl hydrogen L(+) tartrate from the results of hydrolysis experiments and from the identifications of the constituents of the molecule, and named “pretaric acid.” Tartaric acid was evidently produced from pretaric acid by intact cell culture. Clearly, then, pretaric acid appears to be an intermediate in the formation of tartaric acid from 5-ketogluconic acid. The authors assumed that in the formation of pretaric acid from 5-ketogluconic acid, a Baeyer-Villiger type oxidation occurred.     

Reovirus-directed Ribonucleic Acid Synthesis in Infected L Cells

Reovirus replication in L-929 mouse fibroblasts was unaffected by 0.5 mug of actinomycin per ml, a concentration which inhibited cell ribonucleic acid (RNA) synthesis by more than 90%. Under these conditions of selective inhibition, the formation of both single-stranded and double-stranded virus-specific RNA was detected beginning at 6 hr after infection. The purified double-stranded RNA was similar in size and base composition to virus RNA and presumably was incorporated into mature virus. The single-stranded RNA formed ribonuclease-resistant duplexes when annealed with denatured virus RNA but did not self-anneal, thus indicating that it includes copies of only one strand of the duplex. The single-stranded RNA was polyribosome-associated and may function as the virus messenger RNA. Production of both types of virus-induced RNA required protein synthesis 6 to 9 hr after infection. At later times in the infectious cycle, only double-stranded RNA synthesis was dependent on continued protein formation.     

微波诱变L(+)-乳酸高产菌株的选育

为了获得L-乳酸高产菌株,对干酪乳杆菌（Lactobacillus casei）CICC6028进行微波诱变。通过考察微波辐照功率和时间等因素对诱变结果的影响,得出最佳诱变方法是：间歇诱变方法,微波输出功率480W,辐照时间40s。最后得到一株遗传稳定的L（＋）-乳酸高产菌株MW-46,产酸量最高为98．12g／L,与出发菌相比,提高了54．14％。     

5'-Azido-N-1-Napthylphthalamic Acid, a Photolabile Analog of N-1-Naphthylphthalamic Acid : Synthesis and Binding Properties in Curcurbita pepo L

A photolabile analog of N-1-naphthylphthalamic acid (NPA), 5′-azido-N-1-naphthylphthalamic acid (Az-NPA), has been synthesized and characterized. This potential photoaffinity label for the plasma membrane NPA binding protein competes with [³H]NPA for binding sites on Curcurbita pepo L. (zucchini) hypocotyl cell membranes with K_0.5 = 2.8 × 10⁻⁷ molar. The K_0.5 for NPA under these conditions is 2 × 10⁻⁸ molar, indicating that the affinity of Az-NPA for the membranes is only 14-fold lower than NPA. While the binding of Az-NPA to NPA binding sites is reversible in the dark, exposure of the Az-NPA treated membranes to light results in a 30% loss in [³H]NPA binding ability. Pretreatment of the membranes with NPA protects the membranes against photodestruction of [³H]NPA binding sites by Az-NPA supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment.     

Synthesis and biological activity of (+)-hedychilactone A and its analogs from (+)-sclareolide

Natural product hedychilactone A (3) has been synthesized from (+)-sclareolide by an efficient route. Two of the synthetic intermediates, 10 and 12, have shown strong growth inhibition effects against five cancer cell lines, human umbilical vein endothelial cell (HUVEC) and nitric oxide (NO) production. In particular, compound 15 showed selective inhibition activity against HUVEC growth without any cytotoxicity among tested cancer cell lines.     

Sites of Abscisic Acid Synthesis and Metabolism in Ricinus communis L

The sites of abscisic acid (ABA) synthesis and metabolism in Ricinus communis L. were investigated by analyzing the levels of ABA and its two metabolites phaseic acid (PA) and dihydrophaseic acid (DPA) in the shoot tips, mature leaves, and phloem sap of stressed and nonstressed plants.     

Biosynthesis of (+)-Tartaric Acid from l-[4-C]Ascorbic Acid in Grape and Geranium

The metabolic fate of l-[4-¹⁴C]ascorbic acid has been examined in the grape (Vitis labrusca L.) and lemon geranium (Pelargonium crispum L. L'Hér. cv. Prince Rupert) under conditions comparable to data from l-[1-¹⁴C]ascorbic acid and l-[6-¹⁴C]ascorbic acid experiments. In detached grape leaves and immature berries, l-[4-¹⁴C]ascorbic acid and l-[1-¹⁴C]ascorbic acid were equivalent precursors to carboxyl labeled (+)-tartaric acid. In geranium apices, l-[4-¹⁴C]ascorbic acid yielded internal labeled (+)-tartaric acid while l-[6-¹⁴C]ascorbic acid gave an equivalent conversion to carboxyl labeled (+)-tartaric acid. These findings clearly show that two distinct processes for the synthesis of (+)-tartaric acid from l-ascorbic acid exist in plants identified as (+)-tartaric acid accumulators. In grape leaves and immature berries, (+)-tartaric acid synthesis proceeds via preservation of a four-carbon fragment derived from carbons 1 through 4 of l-ascorbic acid while carbons 3 through 6 yield (+)-tartaric acid in geranium apices.     

Optimization of the Process for the Production of L(+)‐Lactic Acid from Cull Potato by Rhizopus oryzae

Cull potato is currently an under‐utilized biomass in the potato processing states of the USA. L(+)‐Lactic acid production by three Rhizopus strains and one homofermentative, facultative anaerobic Lactobacillus amylophilus strain was investigated using potatoes as the sole nutrient supply in the culture medium. Rhizopus oryzae NRRL 395 was chosen as the strain for further studies because it showed the highest lactate yield. The fermentation conditions for seed cultures were studied for three treatment structures using a completely randomized design. Optimum conditions for the seed culture were determined to be 2 % potato medium, 10⁴ spores/mL concentration, and 24 h of fermentation. Plackett‐Burman and central composite designs were used to screen and optimize the factors for lactic acid production. Substrate (potato) concentration, fermentation temperature, and shaking speed were found to be the most significant factors affecting both the yield and concentration of lactate. Optimum values for substrate concentration, fermentation temperature, and shaking speed were 10 %, 27 °C, and 170 rpm, respectively. Under these optimum conditions, the lactate concentration was predicted by the model to be 35.5 g/L, which was verified by the experimental data (33.3 g/L). The results indicate that cull potato can be an effective feedstock for R. ryzae NRRL 395 in the production of lactic acid.     

Nephrotoxic Lesions from 5-Aminosalicylic Acid

5-Aminosalicylic acid given to rats as a single intravenous injection led to necrosis of the proximal convoluted tubules and of the renal papilla. These two lesions developed at the same time and the cortical lesions did not appear to be a consequence of the renal papillary necrosis. Since the compound possesses the molecular structure both of a phenacetin derivative and of a salicylate these observations may be relevant to the problem of renal damage incident to abuse of analgesic compounds and suggest the possibility that in this syndrome cortical lesions may develop independently of renal papillary necrosis.     

The Effect of 2,3.5 Triiodobenzoic Acid on Caulogenesis in Callus Cultures of Tomato and Pelargonium

Stem explants from winter grown tomatoes cultured on a cytokinin, auxin-free medium, developed one or two adventitious shoots at the top end of the explant. Addition of the auxin transport inhibitor. 2,3,5-triiodobenzoic acid (TIBA) to the medium stimulated caulogenesis with loss of polarity. Callus, initiation in pelargonium and ‘geranium’ petiole explants requires both auxin and cytokinin. On transfer, after callus induction to an auxin-free medium, rhizogenesis occurs in pelargonium cultures followed by caulogenesis. Few shoots develop and unless these are removed, further caulogenesis is suppressed. Bud-like structures were formed in the callus. Subculture on auxin-free medium containing cytokinin and TIBA resulted in shoot formation from these bud-like organs. An analogy with apical dominance is suggested. In ‘geranium’ callus, shoots developed with a low frequency (c. in 2% of the cultures): caulogenesis was increased to 80% when calli were subcultured from auxin-free, cytokinin medium after green nodule formation to cytokinin-TIBA medium. Histological studies of green nodules in ‘geranium’ callus indicated a variation in morphological development within and between nodules. It is suggested that auxin synthesis may occur at some microscopic stage in morphogenesis in ‘geranium’ cultures which suppresses further caulogenesis. This may be overcome by the addition of TIBA to the medium at the appropriate stage in morphogenesis. The possible interaction of endogenous auxin in morphogenesis is discussed.