DIVERSITY OF HALOGENATED SECONDARY METABOLITES IN THE RED ALGA LAURENCIA NIPPONICA (RHODOMELACEAE,CERAMIALES)1,2

Many morphologically similar, but chemically distinct, populations have been found in the marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) growing in Japan. Each chemical type is characterized by a specific end-product of halogenated secondaly metabolite synthesis: chamigrane-type sesquiterpenoids such as prepacifenol and halochamigrene epoxide and C₁₅ bromoethers such as laurencin, laureatin, isoprelaurefucin, epilaurallene, and kumausallene. These seven types of secondary metabolite syntheses remained the same in the wild and under various culture conditions. Because bromoethers and terpenoids are probably synthesized by different metabolic pathways, it is virtually certain that different sets of enzymes participate in their synthesis. Prepacifenol- and laureatin-producing populations were selected as representatives of terpenoid and bromoether groups, respectively. F₁ tetrasporophytes derived from crosses between reciprocal, female and male gametophytes of prepacifenol- and laureatin-producing strains bore both types of metabolites, suggesting that the genes Producing these enzyme systems are encoded by nuclear genomes. The F₁ gametophytes resulting from the reciprocal crosses produced either prepacifenol or laureatin, and the four individuals derived from spore tetrads (a set of tetraspores derived from a single tetrasporangium) produced either prepacifenol or laureatin in a 1:1 ratio, indicating that genes participating in terpenoid synthsis and those participating in bromoether synthesis are on different loci of homologous chromosomes and are segregated at meiosis (tetrasporogenesis). One individual of this interpopulational F₁ gamtophyte produced both parental types of metabolite, perhaps indicating the occurrence of a recombination type. Natural hybrid individuals, including such recombination-type gametophytes, were found in a sympatric locality at which these two chemical types occur. F₁ tetrasporophytes derived from crosses between respective prepacifenol- and laureatin-producing strains and their F₁ gametohytes produced only parental-type metabolite-producing plants. These results indicate that the diverse chemical types can be referred to as races (chemical races).     

Structure-spectrum correlations in nucleic acids. I. Raman lines in the 600-700 cm-1 range of guanosine residue.

Raman spectra of nine crystals of known structures which involve guanosine moieties with various conformations have been observed. It has been established that a guanosine residue with the C3'endo-anti conformation gives a strong Raman line at 666 +/- 2 cm-1. It has also been found that the residue with 04'endo-anti gives a strong Raman line at 682 cm-1, and C3'exo-syn at 616 cm-1. The usefulness of these structure-spectrum correlations in the conformation studies of polynucleotides are shown.     

Comparative reproductive patterns in culture of differentGigartina subgenusMastocarpus andPetrocelis populations from northern Japan

Samples of theGigartina pacifica-ochotensis complex were collected at 21 localities around Hokkaido and northern Honshu. The carpospore and blade tip cultures showed 3 reproductive patterns. (1) 237 (86.8%) of the 273 cultured isolates derived from single plants have a direct type of life history. (2) 29 (10.6%) isolates exhibited a heteromorphic type with the alternation of foliose gametophytes and crustose tetrasporophytes. (3) 7 (2.6%) isolates showed a mixed pattern in which carposporelings developed intoPetrocelis-like crusts, basal discs with uprightGigartina blades, or chimera-like discs with compositePetrocelis-Gigartina anatomy. CulturedGigartina blades derived from bothG. pacifica andG. ochotensis were similar in morphology. In 18 cultures from 5 localitiesPetrocelis tetraspores developed into dioeciousGigartina gametophytes. A single tetrasporeling grew into aGigartina plant that reproduced directly. In hybridization experiments with 8 male and 14 female isolates from 4 localities on Hokkaido 85 (78.0%) of 109 were positive. On the basis of these and earlier studies it is concluded that a single species is present in northern Japan:G. pacifica Kjellm. has priority overG. ochotensis (Rupr.) Rupr. ex Yendo.     

Properties of membrane-bound α-glucosidases: Possible sugar receptor protein of the blowfly, Phormia regina

Previously reported PII-type α-glucosidase located in the precipitate of the labellar homogenate of the blowfly Phormia regina was solubilized by sodium deoxycholate (DOC) and further separated into three isozymes with different molecular weight: PII-M (mol. wt 9 × 10⁴). PII-D (mol. wt 2 × 10⁵) and PII-T (mol. wt 8 × 10⁵) by molecular sieve chromatography on Biogel P-300 or Ultragel AcA-34. These three isozymes had almost the same K_m's and relative values of V_m's for several substrates, suggesting that they had the same common active site.PII-D and PII-T are more strongly embedded in the membrane than PII-M, because the proportion of PII-D and PII-T was much increased when the remaining glucosidase in the precipitate after the first solubilization was reextracted by DOC. A large peak of α-glucosidase isozyme P-IV which preferentially hydrolyze sucrose eluted just after P-II (soluble P-II) when the supernatant fraction of the labellar homogenate was chromatographed on DEAE-Sephadex A-50. P-IV was scarcely present in the precipitate fraction.Soluble P-II had the same mol. wt as PII-M and had similar properties to PII-M except for the ratio of V_m's.A large proportion of PII-D was contained in the well washed labellar integuments, a preparation rich in labellar chemosensilla. It suggests that most of the insoluble α-glucosidase contained in the dendrite in labellar chemosensilla is PII-D. PII-D (and PII-T) are possible sites of the pyranose receptor molecule because their properties and localization agree well with those of the receptor.     

Germitorosone and methylgermitorosone,two hydroanthracene derivatives from seedlings of Cassia torosa

Two new yellow pigments, germitosone and methylgermitorosone, were isolated from the seedling of Cassia torosa. The structures of these substances were established as 3,7 dimethyl - 6 - methoxy - 1 - oxo - 2,3,8,9 - tetrahydroxy - 1,2,3,4 - tetrahydroanthracene and 6,9 dimethoxy - 3,7 - dimethyl - 1 - oxo - 2,3,8 - trihydroxy - 1,2,3,4 - tetrahydroanthracene respectively.     

Regulation of the production of the agglutination substances responsible for sexual agglutination in Saccharomyces cerevisiae: Changes associated with conjugation and temperature shift

Summary Isolated zygotes showed self-agglutination caused by the sex-specific glycoproteins, the agglutination substances responsible for sexual agglutination. The agglutination substances of both a and mating types were detected in the extracts obtained by the autoclave method from zygotes. Although the first diploid daughter cells from zygotes showed self-agglutinability, the self-agglutinability decreased gradually in the successive diploid daughter cells. The self-agglutination in diploid cells was also brought about by the complementary binding of the sex-specific agglutination substances of opposite mating types.The constitutive sexual agglutinability in a and cells was lost with concomitant loss of the agglutination substances in both cell wall and cytoplasmic fractions when cultured at a temperature higher than 35°C.The repression of the production of the agglutination substances was reversed by the opposite mating type pheromones even at the repressive temperature, 36°C, associated with the appearance of sexual agglutinability. The sex pheromones, a substance-I and substance-I, and the binding substance for substance-I were produced even at 36°C, repressive for the production of the agglutination substances.     

A probable lack of function of c-type cytochrome in the photosynthetic system of the blue-green alga Anabaena variabilis

Quantitative study of the cytochrome c acting in the photosyntheticsystem of the blue-green alga Anabaena variabilis (M-2) wasdone with membrane fragments and intact cells. Membrane fragments highly active in the NADP⁺-Hill reaction(above 200 µmoles/mg chl.a;-hr) retained photoresponsivecytochrome c equal only one-tenth that of P700, while the plastocyanincontent was almost equal to that of P700. The cytochrome contentin intact cells was a little larger than that in membrane fragmentson the chlorophyll a basis. However, the values relative toP700 (1/9) and plastocyanin (1/10) were identical with thosein membrane fragments. The content was also far smaller thanthat of reaction center II's (1/6). If the cytochrome mediatesall electrons from reaction center II, the cytochrome oxidation-reductionshould have a rate constant of 2.4?102 sec^–1 which isone order above of the rate constant of the cytochrome reduction(2.3 to 3.5?10¹sec^–1). These quantitative relationshipsindicate that in Anabaena variabilis (M-2), c-type cytochrome,either cytochrome f or algal cytochrome c, cannot function inthe main electron flow between two reaction centers. (Received September 8, 1978; )     

Studies on Thin-Layer Chromatography after Incubation with [35S]Methionine as an Aid to Identification of Mycobacteria

Thin-layer chromatography (TLC) of ethyl ether-ethanol extracts of mycobacteria obtained after incubation with [³⁵S] methionine is useful for differentiation among mycobacterial species, as the distribution of radioactive spots in TLC shows a characteristic pattern except for a few species, including M. intracellulare and M. gordonae. Some supplementary studies have been carried out in the present investigation and the following results have been obtained.

相似文献   

Effect of 6059-S,a novel oxacephem,on cross-linking reaction of peptidoglycan biosynthesis in Escherichia coli,Pseudomonas aeruginosa and Serratia marcescens

The effect of 6059-S, a novel 1-oxacephem, on peptidoglycan synthesis was investigated using ether-treated cells of Escherichia coli K 12, Pseudomonas aeruginosa KM 338 and Serratia marcescens IFO 12648. The cross-linking reaction of peptidoglycan synthesis in these organisms was inhibited by markedly low concentration of 6059-S.Non-standard abbreviations PBP penicillin binding protein - MIC minimum inhibitory concentration - ETB ether treated bacterial cells - SDS sodium dodecylsulfate     

Phlegmacins and anhydrophlegmacinquinones: Dimeric hydroanthracenes from seedlings of Cassia torosa

From seedlings of Cassia torosa four dimeric hydroanthracenes have been isolated. Two, a pair of atropisomeric dimers consisting of two molecules o