Preliminary investigation of diatoms growing on artificial substratum in the Eastern Harbour of Alexandria

The present investigation was carried out to estimate the growth of marine epiphytes on submerged glass slides. The study was performed in the Eastern Harbour of Alexandria. Diatoms dominated the epiphyticflora. They were represented by 33 genera. The genus Navicula included 9 species and was mainly represented by Navicula grevillei 80.4% of the genus number and less so by N. ammophila 13.1%. Navicula spp. appeared throughout the year with their maximum counts of 136769 cell/cm[2] by the end of the third week of December. The genus Grammatophora comprised 3 species namely; G. marina 55.7% of the genus number, G. oceanica 36.8% and G. anoulosa 7.5%. They appeared throughacet the year with a peak of 56123 cell/cm[2]after the second week of December. The genus Licmophora included 3 species, namely L. paradoxa 60.9% of the genus number, L. lvnobei 36.6% and L. flagellate 2.5%. The genus reached its maximum counts in the second week of December 69138 cell/cm[2]. The genus Nitzschia com prised eleven species and one variety. It was dominated by N, closterium 41.1% of the genus number, N, lonoissima 25.5% and N. lanceolata 17.0%. The genus showed a peak after the first week of both July 50740 cell/cm2 and August 33230 cell/cm[2]

Urease in ulva lactuca chlorophyta: uvales

Urease [Urea amidohydrolase] was isolated from the green alga, Ulva lactuca L. and purified 127 fold by a procedure that included [NH[4]]2SO][4] fractionation and column chromatography using Sephadex G-200 followed by DEAE-cellulose. The preparation gave two bands when analysed by polyacrylamide gel electrophoresis. The enzyme had a pH optimum of 8.1 in Tris-HCl buffer at 30?C and required -SH groups for activity. Its molecular weight and apparent K[m]values were estimated to be 478600 and 238 uM respectively

Studies on the bioconcentration of chlorinated hydrocarbon insecticides by algae from aqueous systems

Accumulation of three chlorinated hydrocarbon insecticides: DDT, Dieldrin and Lindane [gamma BHC] by the green algae Chlorella fusca and Scenedesmus acuminatus and the diatom Phaeodactylum tricornutum was studied. The microorganisms were exposed to 0.1 ppm [0.1 ug m1[-1]][14]C, DDT, dieldrin or BHC for a period of four hours at controlled temperature. The concentration of DDT and dieldrin within these algae was much higher than in the surrounding medium which indicates that these organisms can sorb and concentrate DDT and dieldrein. The highest accumulation of insecticides was observed for DDT and the lowest for gamma BHC. Bioconcentration of insecticides was higher in Phaeodactylum tricornutum than in Chlorells fusca or Scenedesmus acuminatus. There was a definite relationship between the uptake of DDT, dieldrin and BHC by the various algae and the hexane/water partition coefficient of these insecticides

Lipoxygenase from Ulva lactuca [Ubvales, chloropyta]

Lipoxygenase enzyme [linoleate oxygen oxidoreductase EC 1.99.2.1] was separated and purified from the green alga Ulvalactuca by extraction of the cell-free extract, precipitation with 45% to 70% solid ammonium sulfate and chromatography on DEAE Sephadex A 50. This preparation has given two bands [Lipoxygenase 1 and 2] by disc gel electrophoresis. Lipoxygenase enzyme from Ulva has been obtained in 60% yield with specific activity in the range of 1262 n mol, hydroperoxylinoleate mg[-1]protein. A purification 63-fold was achieved from Ulva. The optimum pH of Ulva lipoxygenase is 8.0. The molecular weights of lipoxygenase 1 and 2 were 120000 and 103000 respectively. K[m]and V [max] were 307.6 uM and 250 n mol per mg protein ml[-1]min[-1] respectively. No unusual amino acids were detected by the amino acid analyser. There is no cystine in Ulva lipoxygenase. The iron content of the purified lipoxygenase enzyme was 1.05 ppm