Studies on the metabolism of a sulfur-oxidizing bacterium VII. Oxidation of sulfite by a cell-free extract of Thiobacillus thiooxidans

Properties of the cell-free extract, prepared from a strainof Thiobacillus thiooxidans by sonic disruption followed byfractionation with centrifugatiori, were investigated with referenceto its sulfite-oxidizing activity. Without the addition of cofactors the particulate fraction(F-P)catalyzed oxidation of sulfite with oxygen or bacterial cytochromec-552 obtained from Pseudomonas stutzeri as electron acceptor.TMPD reduced by ascorbic acid was also oxidized by F-P. Thesoluble fraction(F-S) showed no activity in oxidizing sulfiteand TMPD, but stimulated TMPD oxidation by F-P. Oxygen uptake with either sulfite or TMPD as substrate was inhibitedby KCN, NaN₃, CO and c-phenanthroline. CO-Inhibition was reversedby light. Reduction of cytochrome c-552 by sulfite was insensitiveto these agents. Antimycin A markedly inhibited sulfite oxidation with eitheroxygen or cytochrome c-552 as electron acceptor, but was withouteffect on TMPD oxidation. DDC and SAO, both strong inhibitors of sulfur oxidation, didnot affect sulfite and TMPD oxidations. Cytochromes of the a, b and c types were contained in F-P. Thesecytochromes were rapidly reduced when F-P was incubated withsulfite. Cytochrome(s) of the c type was present in F-S, too. ¹VI.=References (3) ²Partly supported by a grant from the Ministry of Education ³Present address: Sanyo Women's College, Hatsukaichi, Hiroshima738, Japan ⁴Present address: Department of Biochemistry, Hiroshima UniversitySchool of Dentistry, Hiroshima 734, Japan (Received May 15, 1970; )     

Incorporation of some possible radioactive intermediates into chlorogenic acid in sliced sweet potato tissue

t-Cinnamic acid-2-¹⁴C, p-coumaric acid-2-¹⁴C and caffeic acid-2-¹⁴Cwere administered to discs of sweet potato roots and incorporationof each radioactive compound into chlorogenic acid was compared.The data suggest that chlorogenic acid is synthesized througheither or both of two major pathways, phenylalanine t-cinnamate t-cinnamoyl derivative p-coumaroyl derivative chlorogenicacid and phenylalanine t-cinnamate p-coumarate p-coumaroylderivative chlorogenic acid. ¹Part 75 of the phytopathological chemistry of sweet potatowith black rot and injury. ²Present address : Department of Biology, Tokyo MetropolitanUniversity, Setagaya-ku, Tokyo. (Received December 23, 1968; )     

A bimodal germination response to temperature in cocklebur seeds. II. ATP and adenylate pool

Abstract. The mechanism involved in a bimodal germination-temperature response in pre-soaked cocklebur (Xanthium pennsylvanicum Wallr.) seeds was studied with special reference to adenylate metabolism. Exposure to either low (optimal at 8°C) or high (optimal at 34°C) temperature which was effective in inducing the germination of the seeds brought about the accumulation of ATP in them. The ATP level remained unchanged at temperatures around 23°C. Pretreatment with KCN, stimulating germination even at 23°C, subsequently increased the ATP content, total adenylate pool and energy charge (EC) in the axial tissue prior to germination above those of the untreated controls. The lower the treatment temperature, the greater the inhibitory effect of KCN on ATP formation. An increase in germination following an increasing duration of pre-soaking at 8°C was comparable to increasing both the ATP content and total adenylate pool of axes, but not the EC value. Similarly, changes in germination following an increased exposure duration at 8°C correlated with changes in ATP content rather than EC value in the axes. Unlike the case of chilling, an increase in ATP level in response to 34°C was greater in the early period of water imbibition, during which times its germination-stimulating effect appeared more striking than in the later period, and it occurred without a concomitant rise in EC value because of the increased supply of AMP. Such a supply of AMP was reduced in the presence of benzohydroxamic acid or propyl gallale, inhibitors of an alternative respiratory pathway. It was thus concluded that both low temperature, coupled with warm temperature, and high temperature, by itself, can induce seed germination by increasing the ATP level as well as the total adenylate pool, but not the EC value, in the axial tissue. Further, that increases in both the ATP level and the adenylate pool especially are required for seed germination to proceed, probably depending on the activities of the cytochrome and alternative respiration pathways, respectively.     

Ubiquitous distribution of fluorescent protein in muscles of four species and two subspecies of eel (genus <Emphasis Type="Italic">Anguilla</Emphasis>)

In this study, the localization of fluorescent protein (FP) was characterized in the muscles of four species and two subspecies of eels Anguilla anguilla, A. australis, A. bicolor bicolor (b.), A. bicolor pacifica (p.) and A. mossambica in addition to the previously reported A. japonica. The open reading frame of each eel FP was 417 bp encoding 139 amino acid residues. The deduced amino acid sequences among the four species and two subspecies exhibited 91.4–100% identity, and belonged to the fatty-acid-binding protein (FABP) family. The gene structure of eel FPs in A. japonica, A. anguilla, A. australis, A. bicolor b., A. bicolor p. and A. mossambica have four exons and three introns, and were common to that of FABP family. The apo eel FPs expressed by Escherichia coli with recombinant eel FP genes were analysed for the fluorescent properties in the presence of bilirubin. The excitation and emission spectra of holo eel FPs had the maximum wavelengths of 490–496 and 527–530 nm, respectively. The holo eel FPs indicated that the fluorescent intensities were stronger in A. japonica and A. bicolor than in A. mossambica, A. australis and A. anguilla. The comparison of amino acid sequences revealed two common substitutions in A. mossambica, A. australis and A. anguilla with weak fluorescent intensity.     

The Development of a High Performance Liquid Chromatograph with a Sensitive On-stream Radioactivity Monitor for the Analysis of 3H- and 14C-labelled Gibberellins

The development of a high performance liquid chromatograph forthe separation of gibberellins is described. The system combineshigh efficiency, peak capacity, and sample capacity with rapidspeed of analysis. In addition, the constructional details ofa sensitive on-stream radioactivity monitor are outlined. Theoverall versatility of the chromatograph is demonstrated bythe separation of a range of ³H- and ¹⁴C-labelled Gibberellinsand gibberellin precursors. The system also has considerablepotential for the analysis of abscisic acid and acidic and neutralindoles.     

Effects of growth conditions on formation of cytochrome system of a denitrifying bacterium, Pseudomonas stutzeri

Cytochrome systems in cells of a denitrifying bacterium, Pseudomonasstutzeri (VAN NIEL strain), grown under different atmosphericconditions were compared with reference to the effects of nitrateand nitrite on cytochrome synthesis. When a culture was sufficiently aerated (aerobic conditions),synthesis of all cytochrome components was repressed, regardlessof the presence or absence of nitrate and nitrite. When aeratedmoderately (semi-aerobic conditions), both soluble and paniculatecytochromes c-552 and cytochrome b-558 contents markedly increasedeven in the absence of nitrate and nitrite. Under anaerobic or semi-aerobic conditions, nitrite inducedcytochrome a₂–c synthesis. This inductive effect of nitritewas counteracted by nitrate. Nitrate also repressed particulatecytochrome c-552 synthesis to some extent but nitrite did not. ¹Present address: Department of Biochemistry, Hiroshima UniversitySchool of Dentistry, Hiroshima, Japan (Received June 24, 1969; )     

Algivory in food webs of three temperate Andean rivers

Food web analyses have been fundamental in understanding community organization and ecosystem functioning. To date, a number of studies demonstrate that stream food webs depend to a large extent on allochthonous detritus, but there are more recent studies that show a high degree of autochthony. Our food‐web study was carried out in three Andean rivers (Coilaco, Guampoe and Trancura) within the catchment area of Toltén River in southern Chile. Based on the analyses of 4251 invertebrate gut contents, we found that these Andean stream food webs are dominated by herbivores (range: 50–73% of all species) supported by a species‐rich algal (basal) component, and characterized by a low proportion of omnivores (range: 8–27% of all species) and predatory species (range: 10–24%). Significant differences in the number of feeding links of the herbivores Meridialis diguillina and Antarctoperla michaelseni and the omnivore Smicridea chilensis were found between seasons. The spring herbivore Aubertoperla sp. showed significant differences between rivers. S. chilensis fed on 50 different prey items as compared with the herbivores whose maximum number of links ranged between 37 and 40. Web sizes ranged between 93 and 131 species and the proportion of top species was distinctly lower than those of basal (up to 0.651 in Coilaco River) and intermediate species. Direct connectance (links per species²) values were low and similar among rivers (range: 0.051–0.074), whereas mean food chain length ranged between 2.23 and 2.90. The distributions of web property values from the Andean rivers differed from those previously published. In contrast to previous predictions, mean food chain length in these Andean streams displayed a scale‐invariant pattern across different web sizes, but it was significantly related to the proportion of intermediate species.     

Studies on organic acid metabolism and ethylene production during controlled atmosphere storage of apples {Mallus pumila MILLER, cv. Rolls)

Organic acid metabolism and ethylene formation during controlledatmosphere storage (CA-storage) of apples (Mallus pumila MILLER,cv Rolls) were studied. A higher titratable acidity was observedin apples during CA-storage as compared to those in air control.The incorporation of atmospheric ¹⁴CO₂ into malic acid was greaterin apples stored in the higher CO₂ concentration. The conversionof succinic acid-¹⁴C into fumaric acid-¹⁴C was slightly lessin the apple in modified high carbon dioxide atmosphere thanthose in air. O₂ uptake and CO₂ output by apple slices weremarkedly inhibited by the addition of succinic and malic acidsat a concentration higher than 25 mM. These factors seem to be the possible cause of a higher acidityof fruits stored in CA-condition. Ethylene production from wholefruits or tissue slices was markedly inhibited under CA-condition. The retardation of acid metabolism and the inhibition of ethyleneproduction of apples during CA-storage seem to be the importantfactors which help to maintain their storage quality. (Received March 18, 1970; )