Significance of betaines in the increased chlorophyll content of plants treated with seaweed extract

Seaweed extract, prepared by alkaline extraction of Ascophyllum nodosum (L.) Le Jol., applied either to the soil or to the foliage of tomato plants, produced leaves with higher chlorophyll levels than those of control plants. The effects on leaf chlorophyll content were investigated using a cucumber bioassay procedure devised for cytokinins. The seaweed extract was shown to increase the chlorophyll levels of the cucumber cotyledons, but ‘peaks’ of activity were obtained when widely different concentrations were used. The possibility that these effects were the result of betaines present in the extract was considered. Glycinebetaine, γ-aminobutyric acid betaine and δ-aminovaleric acid betaine all produced significantly enhanced chlorophyll concentrations in the cotyledons. ‘Peaks’ of activity were observed for each betaine: for glycinebetaine at 10⁻⁶ and between 10⁻⁴ and 10¹ mg 1⁻¹, for γ-aminobutyric acid betaine at 10⁻⁶, between 10⁻⁴ and 10⁻¹, and 10¹ mg 1⁻¹, and for δ-aminovaleric acid betaine between 10⁻⁵ and 10¹ mg 1⁻¹. It was concluded that the effects of enhancing chlorophyll levels produced by the seaweed extract were due, at least in part, to betaines.     

Isolation of a sequence common to A- and B-chromosomes of rye (Secale cereale) by microcloning

The techniques of microdissection and microcloning have been applied to the isolation of B-chromosome DNA from rye. We have identified a DNA sequence on the rye B-chromosome which is homologous to an A-chromosome sequence, and which is dispersed and moderately repeated on the A- and B-chromosomes. This demonstrates that the rye B-chromosome is heterogeneous in the nature of its DNA sequence composition, containing sequences which are present on the A-chromosomes in addition to those not present on the A-chromosomes.     

Growth of a dissociated, filamentous stage of Codium species in laboratory culture

Unialgal cultures were established from isolated utricles for all five Codium species occurring in the British Isles and growth studies performed under different conditions of temperature (10-30 °C), photon irradiance (0-175 μmol m-2 s-1) and salinity (0-100% seawater growth medium). The species studied were C. fragile ssp. tomentosoides, C. fragile ssp. atlanticum, C. adhaerens, C. bursa, C. tomentosum and C. vermilara. All cultures developed into growth forms comprised of branched, dissociated, coenocytic filaments. All grew rapidly in culture, although the conditions for optimum growth sometimes differed for the individual entities. The development of typical Codium plants, with utricles, similar to the parental material, occurred only occasionally. The rapid growth of the dissociated, filamentous forms in laboratory culture led to the provision of sufficient quantities of plant material to enable detailed studies to be made of the lectins present in several of the species. This revised version was published online in August 2006 with corrections to the Cover Date.     

Isolation and characterization of brown algal polyphenols as inhibitors of α-amylase,lipase and trypsin

Extracts ofAscophyllum nodosum, Fucus serratus, F. vesiculosus andPelvetia canaliculata contain inhibitors of α-amylase, lipase and trypsin. The inhibitors were isolated and identified by¹H NMR spectroscopy as polyphenols which have apparent molecular weights in the range from 30 000 to 100 000 daltons, as determined by ultra-filtration with Amicon membranes. These polyphenols account for the whole of the inhibitory activity in crude algal extracts. The compounds inhibit α-amylase and trypsin in an apparently non-competitive manner, when preincubated with the enzymes, and the inhibition is directly proportional to the concentration of the inhibitor. Starch protects α-amylase when added to the enzyme together with the inhibitors. Under this condition the effectiveness of the inhibitors is reduced ten-fold.     

trans-4-hydroxy-β-prolinebetaine,a new betaine fromFurcellaria lumbricalis

From the red marine alga Furcellaria lumbricalis (Huds.) Lamour, a novel betaine has been isolated and characterised from infra-red and nuclear magnetic resonance spectroscopic and mass spectrometric data astrans-4-hydroxy-β-prolinebetaine.     

The relative efficiency of nitrogen fixation in pea root nodules

Summary Experiments were performed to investigate the causes of low relative efficiency, RE, in legume root nodules. Nitrogen fixing activity and RE varied with time of incubation of nodules and with different temperatures and oxygen concentrations. The effects of nitrogen concentration and carbon dioxide concentration were also examined. In each case the RE was inversely related to nitrogen fixing activity; measured by acetylene reduction. Increasing the nitrogen concentration had no effect on either nitrogen fixing activity or RE. Experiments with isolated bacteroids gave higher RE values than the whole nodules from which they were isolated. All the results were consistent with hydrogen inhibition of nitrogenase within the nodule being the cause of low RE.     

Steroidal sapogenins from leaves of some species of Agave and Furcraea

The steroidal sapogenins yielded by the leaves of Agave aurea, A. avellanidens, A. cerulata, A. cerulata ssp. subcerulata, A. cocui, A. goldmaniana, A. shawii and Furcraeamacrophylla are recorded. In all these species, hecogenin and tigogenin were the major sapogenins isolated. Gitogenin was found in the extracts of all the leaf samples, except that of A. shawii, and manogenin and 9-dehydromanogenin in all but that of A. cocui. Chlorogenin was isolated from A. cocui, but was not detected in any of the other species examined. Qualitative and quantitative variations were found in the sapogenin contents of extracts of different regions of the same leaves of A. cocui and F. macrophylla. In particular, hecogenin predominated in the basal regions and tigogenin in the apical.     

Anticoagulant activity of a proteoglycan in extracts ofCodium fragile ssp.atlanticum

Aqueous extracts ofCodium fragile ssp.atlanticum possess marked anticoagulant activity. The compounds responsible appear to be proteoglycans with molecular weights, determined by a low angle, laser light-scattering method, of 1.8 × 10⁶ daltons, with a polydispersity value of 1.2.     

Chemical composition and antioxidant activities of Jeddah corniche algae,Saudi Arabia

The increased use of natural product in the pharmaceutical industry has led to an increase in demand for screening for bioactive compounds in marine algae. An important economic algae, through chemical composition analysis and their antioxidant activities were investigated in this study. Chemical composition analysis of three algal samples from the Chlorophyta Ulva lactuca (U), Phaeophyta Sargassum crassifolia (S) and Rhodophyta Digenea simplex (D) was tested. Main components were sugars (57.40–185.13 mg/g dry weight), uronic acids (29.3–45.26 mg/g dry weight), sulfate (94.7–181.2 mg/g dry weight), amino acids (7.6–16.7 mg/g dry weight) and small amounts of betaines (2.38–8.47 mg/g dry weight). Hydrolyzed chemical composition analysis fractions of algal extract was shown a great proportion of sugars plus sulfate (as polysaccharide composed) ranges between 332 and 538.2 mg/g dry weight with trace amounts of uronic acids (⩽9%). All three algal extract showed antioxidant activities on lipoxygenase, DPPH and on Ames test. Two of aqueous extracts (U and D) inhibited lipoxygenase activity by less than 50%, where as the methanolic extract (S) caused 76% inhibition of the control. In all cases, the methanolic extract were more inhibitory than the aqueous extract. The (S) showed the highest antioxidant activity with DPPH (69%) in aqueous extract and in methanol extract with Ames test (85%). Both U and D showed antioxidant activity with DPPH in hexane by less of 25% where as in both aqueous and methanolic extracts by less than 50% of the control. Aqueous and methanolic extracts of U and D showed high inhibition by Ames test which caused 70% and 75% respectively. IR spectra of algal extracts (U; D and S) range from 1450 to 750 cm⁻¹ were very similar absorption band at 1430, 1370, 1250, 1130, 1110, 1050 and 1020 cm⁻¹. Absorption bands were due to uronic acids, glucosides and sulfate. The presence of sulfated polysaccharide material in the fractions UF2, DF2 and SF2 were found as cell wall storage of marine algae, confirmed by ¹³C NMR spectroscopy. It is concluded that the algal species probably have a different components and can be used in the activities of antioxidant enzymes as reduced the risks of enzymes. But the correlation between the chemical composition and antioxidant activities of algal extracts needs further investigation.Abbreviations: (U), Ulva lactuca; (S), Sargassum crassifolia; (D), Digenea simplex; DPPH, α-diphenyl-β-picrylhydrazyl; HPLC, high performance liquid chromatographic