The metabolism of photosynthetically fixed carbon by isolated chloroplasts from Codium fragile (Chlorophyta: Siphonales) and by Elysia viridis (Mollusca: Sacoglossa)

The metabolism of photosynthetically fixed ¹⁴C by isolated chloroplasts from Codium fragile is compared with that by Elysia viridis (which contains C. fragile chloroplasts). There are marked differences between the two in the formation and subsequent metabolism of both soluble and insoluble products. Less than 6% of the carbon fixed by the isolated chloroplasts during a 15 min pulse of ¹⁴C-bicarbonate in the light is released into the medium over the succeeding 24 h. During photosynthesis glycollate and glucose monophosphate are the only labelled compounds released; after the pulse very little glycollate is released and over 24 h only glucose monophosphate and an unidentified compound are found in the medium. In E. viridis photosynthetically fixed carbon can be recovered from compounds of all major classes found in animals. Soon after the pulse, hexoses are the most heavily labelled compounds, but two hours later amino acids are more heavily labelled than hexoses. The unidentified compound is not found in the animals. E. viridis can absorb and metabolize exogenous glycollate and glucose. Earlier authors' suggestions that glucose is the compound which moves from the chloroplast to the animal cell are discussed, and it is proposed that both glucose monophosphate and glucose are formed outside the chloroplast from triose phosphate exported from it.     

Sterols of the siphonous marine alga Codium fragile

The marine siphonous green alga, Codium fragile, was shown to contain two 25-methylene sterols. These were identified as (24S)-24-ethylcholesta-5.25-dien-3β-ol and the previously unknown (24S)-24-methylcholesta-5,25-dien-3β-ol for which the trivial name codisterol is proposed.     

管藻目绿藻叶绿素蛋白复合物特性及比较研究

采用温和的ＰＡＧＥ法从管藻目刺松藻（Ｃｏｄｉｕｍ ｆｒａｇｉｌｅ （Ｓｕｒ．）Ｈａｒｉｏｔ）和假根羽藻（Ｂｒｙｏｐｓｉｓ ｃｏｒｔｉｃｕｌａｎｓ Ｓｅｔｃｈ．）,丝藻目绿藻软丝藻（Ｕｌｏｔｈｒｉｘ ｆｌａｃｃａ （Ｄｉｌｌｗ．）Ｔｈｕｒ．）,及菠菜（Ｓｐｉｎａｃｉａ ｌｏｅｒａｃｅａ Ｍｉｌｌ．）中分别得到１１、１１、７和９种色素蛋白复合物,对复合物的多种特性,包括分子量、Ｃｈｌ ａ／ｂ比值、叶绿     

Prasinoxanthin—a chemosystematic marker for algae

A new coccoid marine alga (clone Ω 48-23) contained chlorophylls a and b and carotenoids consisting of β,β-carotene (3% of total), β,ε-carotene (1%), zeaxanthin (2%), neoxanthin (21%), two minor unknowns (2 + 2%) and prasinoxanthin (69%). Prasinoxanthin is identical with xanthophyll K, previously considered characteristic of prasinophytes. From spectroscopic and chemical evidence prasinoxanthin is assigned the structure (3′R,-6′R)-3,6,3′ trihydroxy-7,8-dihydro-γ,ε-caroten-8-one, with tentative 3R,6R chirality from biogenetic considerations, thus representing the first algal carotenoid with a γ-end group. The structural relationship between prasinoxanthin and siphonaxanthin (ex Prasinophyceae and Siphonales) is discussed in chemosystematic terms.     

管藻目绿藻叶绿素蛋白复合物特性及比较研究

By mild PAGE method, 11, 11, 7 and 9 chlorophyll-protein complexes were isolated from two species of siphonous green algae (Codium fragile (Sur.) Hariot and Bryopsis corticulans Setch.), green alga (Ulothrix flacca (Dillw.) Thur.), and spinach (Spinacia oleracea Mill.), respectively. Apparent molecular weights, Chl a/b ratios, distribution of chlorophyll, absorption spectra, low temperature fluorescence spectra of these complexes were determined, and compared with one another. PSⅠ complexes of two siphonous green algae are larger in apparent molecular weight because of the attachment of relative highly aggregated LHCⅠ. Four isolated light-harvesting complexes of PSⅡ are all siphonaxanthin-Chl a/b-protein complexes, and they are not monomers and oligomers like those in higher plants. Especially, the absence of 730 nm fluorescence in PSⅠ complexes indicates a distinct structure and energy transfer pattern.     

Free protein amino acids of some Mediterranean Siphonales

Fifteen free protein amino acids have been quantitatively determined in nine green algae belongin to the order Siphonales. In all the species examined, aspartic acid, glutamic acid, alanine, glycine and serine dominate. Wide differences of the relative amounts of these amino acids in the various regardless of the genus were observed.     

Sterol composition of some mediterranean green algae

The distribution of sterols in ten Mediterranean green algae has been examined. Clionasterol is typical for the Siphonocladales and all the species of the Siphonales not belonging to the genus Codium, which is characterized by clerosterol. 28-Isofucosterol has been confirmed to be characteristic of the Ulotrichales.