Chloramphenicol Induced Changes in Some Respiratory Characteristics of Potato Tuber Callus

Chloramphenicol (CAP), an inhibitor of the mitochondrial proteinsynthesis inhibits callus induction and subsequent growth ofpotato tuber tissue discs. Tissue respiration increase did notoccur in the presence of CAP. Both with and without CAP theinitially CN^–-sensitive tissue becomes totally CN^–-resistantin 1–2 weeks. CAP blocks the development of mitcohondrial cytochrome oxidase.A gradual decrease in the activities of cytochrome oxidase andof cytochrome pathway-mediated mitochondrial respiration isfound in CAP-tissue. The mitochondrial alternative pathway whichis absent in mitochondria from freshly sliced tissue developsduring incubation both in the absence and presence of CAP. Thealternative pathway is only operative in uninhibited state IIIrespiration in mitochondria from CAP-tissue. Cycloheximide, an inhibitor of the cytoplasmic protein synthesisinhibits the developments of the alternative pathway and ofthe cytochrome pathway. Alcohol dehydrogenase activity increasestenfold in the tissue during two weeks of incubation on mediawith and without CAP. Alcohol production in the tissue did nottake place in the controls nor in the CAP-treated tissue. (Received April 18, 1981; Accepted July 17, 1981)     

Binding-Dissociation Properties of Potato Tuber Cell Wall-Associated {beta}-N-acetylglucosaminidase

The binding-dissociation properties of an endogenous cell wallprotein, ß-GlcNAcase, was compared to an artifactuallybound basic protein (cytochrome c) and acidic proteins (bovineserum albumin, -lactalbumin, ß-lactoglobulin and cytosolicß-GlcNAcase). Salt dissociation curves with monovalent,divalent and trivalent salts all indicated that the endogenouscell wall enzyme binds much tighter to the wall than does anyartificially bound protein. At high ionic strength (I=1.5),ammonium sulfate was as efficient as NaCl, KCl and LiCl in dissociatingthe cell wall enzyme. The pH of the dissociation medium onlyhas an effect on the dissociation of cell wall enzymes whenthe ionic strength of the buffer is low. The binding of proteinto purified cell walls is pH dependent in the physiologicalrange only if the protein has an acidic isoelectric pH. (Received May 27, 1992; Accepted August 3, 1992)     

Respiration and Carbohydrate Metabolism of Potato Tuber. Part I

The activity of tyrosinase, isolated from potatoes is suppressed in the presence of redox dyes and the composed dehydrogenase systems. The oxygen uptake of potato tuber increases, but after being cut into slices the dehydrogenase activity of tuber decreases in the lapse of time. This increase in oxygen uptake is caused by tyrosinase. Accordingly, tyrosinase does not seem to play the role as a terminal oxidase in the electron transferring systems.     

用聚合酶链式反应（PCR）检测马铃薯纺锤块茎类病毒

用DNA合成仪合成两个马铃薯纺锤块茎类病毒(Potato spindle tuber viroid, PSTVd)特异性引物,从感病的马铃薯块茎组织的核酸抽提液中,用反转录酶合成PSTVd eDNA,然后用PCR法进行扩增,扩增产物用电泳检测,建立了用PCR法检测PSTVd的新方法。结果表明,该方法特异性强,灵敏度可达0.15pg,比现有其它检测方法高,而且样品用量少。     

Cysteine and Methionine Regulation of Sulfate Uptake in Potato Tuber Discs (Solanum tuberosum)

Sulfate uptake in potato tuber discs is inhibited by cysteine and methionine with an 8 h lag period. Cysteine, but not methionine, inhibition can be reversed by washing the treated discs. During the experimental period cysteine is rapidly metabolized, while methionine persists as a free amino acid. Amino acid inhibition of sulfate uptake is overcome by increasing sulfate concentration. The kinetic parameters change suggesting a loss of flexibility of the sulfate uptake system caused by sulfur amino acids.     

Some Properties of Synthetic UDP(2)-fructose

UDP(2)-fructose was synthesized from d-fructofuranose-2-phosphate by the method of Khorana et al. The product thus obtained showed slightly higher paper chromatographic mobilities than those of UDP-glucose and UDP(1)-fructose, and a large negative optical rotation. In acid hydrolysis, this substance was quickly converted into UDP(1)-fructose and then the latter is hydrolyzed to UMP and fructose-1-phosphate. The rate constant of this first step is far larger than the acid hydrolysis rate constant of natural UDP-fructose isolated from the tubers of Jerusalem artichoke. When treated with the snake venom nucleotide pyrophosphatase, UDP(2)-fructose was splitted into UMP and a substance having the same paper chromatographic mobility as that of fructofuranose-2-phosphate. From these results and those reported previously, the structure of the synthetic product may be UDP(2)-β-d-fructofuranose. It was argued that the natural UDP-fructose may be UDP(2)-α-d-fructofuranose.     

The determination of the red cell isoenzymes 6-phosphogluconate dehydrogenase (E.C.1.1.1.44) and acid phosphatase (E.C.3.1.3.2) by means of agarosegel thinlayer electrophoresis (author's transl)

Methods for the determination of the red cell isoenzymes 6-PGD and acP by means of agarosegel thinlayer electrophoresis are referred. Using these relatively simple techniques, results can be obtained after at least two hours. The quality of separation in both systems is higher than that obtained after starch gel electrophoresis.     

Determination of isozymes of phosphoglycerate-mutase (E.C.2.7.5.3) and enolase (E.C.4.2.1.11) in human erythrocytes.

525 human hemolysates were tested for the isozymic patterns of phosphoglycerate mutase and enolase. Genetic models for interpreting the pherograms are suggested.     

Molecular Comparison of Pyrophosphate- and ATP-Dependent Fructose 6-Phosphate 1-Phosphotransferases from Potato Tuber

The aim of this work was to compare the molecular properties of pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP) and ATP:fructose 6-phosphate 1-phosphotransferase (PFK). Both enzymes were purified to apparent homogeneity from potato tubers (Solanum tuberosum cv Record). Neither PFP nor PFK preparations contained detectable activity of the other enzyme. PFP was composed of two polypeptides of apparent molecular weight 58,000 and 55,700 whereas PFK contained four polypeptides of apparent molecular weight between 46,300 and 53,300. Chemical cleavage of individual PFP and PFK polypeptides gave a different set of fragments for each polypeptide. On Western blots antisera against PFP failed to cross-react with any of the four PFK polypeptides, and antibodies against PFK failed to bind to either of the PFP polypeptides. Antibodies that immunoprecipitate PFP activity had no effect on PFK activity. Conversely, antibodies against the four PFK polypeptides precipitated the activity of PFK, but not that of PFP. This work shows that potato tuber PFP and PFK are composed of distinct, unrelated polypeptides and indicate that interconversion between PFP and PFK is unlikely.     

Rapid Detection of Potato Spindle Tuber Viroid (PSTV) by Dot Blot Hybridization

A PSTV probe of 350 bases, prepared in our laboratory, was used to detect picogram quantities of viroids by a simplified, improved, dot blot, hybridization technique in crude potato and tomato extracts. Optimum conditions for certification of PSTV-free potato plants were established, involving formamide concentration, washing stringencies, exposure time during autoradiography and method of probe radiolabelling. Ten pg of purified PSTV in water and 50 pg of purified PSTV added to healthy plant extract were detected. Also hybridization signals could be detected from as little as 0.075 mg of infected plant tissue.     

Production of Potato Spindle Tuber Viroid (PSTV) by Large Scale Fermentation of PSTY-Infected Potato Cell Suspension Cultures

Berlin, J., Wray, V., Forche, E., Reng, H.–G , Schler,H, Luckinger, R. and Mhlbach, H.–P. 1985. Production ofpotato spindle tuber viroid (PSTV) by large scale fermentationof PSTV–infected potato cell suspension cultures.—J.exp. Bot 36: 1985–1995. Cell suspension cultures of Solatiumdemissum, infected with the potato spindle tuber viroid (PSTV),were scaled up to volumes of up to 800 dm³ to provide sufficientand uniform plant material for subsequent studies on viroidbiosynthesis. Here we describe the technological aspects ofproducing the required amounts of biomass and viroid. The cells,which had been maintained on a medium containing expensive coconutmilk, were first adapted to rapid growth on the less expensiveB5–medium. The physiological state of the cells was monitoredby in vivo ³¹P–NMR spectroscopy Under the chosen conditionsthe scale–up from 10 dm³ inoculum from shake flasks tothe harvest of the 800 dm³ stirred fermenter lasted 38 d andprovided 112 kg biomass. Growth characteristics and viroid productionin shake flasks and large bioreactors were rather similar. Gelelectrophoretic analysis of isolated nucleic acids using silverstaining and Northern blot hybridization revealed a PSTV–contentof approximately 700 µg PSTV per kg fresh mass of culturedcells. Key words: Solanum demissum, plant cell cultures, potato spindle tuber viroid, biomass production, fermentation, in vivo ³¹P-NMR     

Mercury and the activity of erythrocyte and bone marrow glutathione reductase (E.C. 1.6.4.2.) and glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49) in rats

These studies were carried out on male Wistar rats. Erythrocyte and bone marrow activity of glutathione reductase (GR - E.C. 1.6.4.2) and glucose-6-phosphate dehydrogenase (G6PD - E.C. 1.1.1.49) were determined as affected by mercury. Under physiological conditions the above enzymes were found to be markedly more active in the bone marrow than in erythrocytes. The present experiments have revealed that within the first days there will be an increase in enzyme activity in the bone marrow as well as in glutathione reductase in erythrocytes. Simultaneously, a decline in the activity of erythrocytes could be observed which began within the very first days of the experiments as well as a decrease in the bone marrow, which occurred later in the course of the experiment.     

Alteration of Coding Properties of Polysome-Associated Messenger RNA in Potato Tuber Slices during Aging

Kinetics of polysome formation, translational capacity, and coding properties of polysome-associated messenger RNA were investigated in potato tuber tissue discs during aging. Polysome content rapidly increased immediately after slicing from 14% of total ribosomes in freshly sliced discs to 55% within 12 hours of aging. The amount of polysomal RNA also increased 5-fold during this period. Translational capacity of polysome-associated messenger RNA increased in parallel with the increase in content of polysomal RNA of the tissue discs when measured in a wheat germ cell-free system. Analysis of the in vitro translation products by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the majority of polypeptides coded by the messenger RNA did not vary greatly during the period of rapid polysome formation. Three types of messenger RNA were found to change in amount during that period: those which appeared only after aging, those which disappeared during aging, and those which disappeared early but reappeared later in the aging period.     

Isolation and Some Properties of Anti-proteolytic Polypeptides from Potato

A new nematicidal alkaloid, peniprequinolone (1), together with the known alkaloids penigequinolones A and B (2a, 2b), 3-methoxy-4-hydroxy-4-(4′-methoxyphenyl)quinolinone (3), and 3-methoxy-4,6-dihydroxy-4-(4′-methoxyphenyl)quinolinone (4), were isolated from Penicillium cf. simplicissimum (Oudemans) Thom. Cyclopenin (5) and a compound (6a/6b) structurally related to cyclopenin also were isolated from the fungus, and their structures were established by spectroscopic analysis. The biological activities of 1, 2, 3, 4, and 5 were examined by a bioassay with root-lesion nematodes.