Seasonal changes in the content of lipids and photosynthetic pigments in a brown alga Saccharina cichorioides

Seasonal changes in the contents of lipids and photosynthetic pigments (PSP) were investigated in a brown alga Saccharina cichorioides Miyabe (Phaeophyceae, the family Laminariaceae). The content of lipids varied from 0.27 to 0.60% of the algal fresh weight. The content of glyceroglycolipids (GL) was much greater in the time of spore formation (June–July and September–October), phospholipids — in the spring and in September–October, and the content of neutral lipids — in the spring and in November. In the period of spore release (August and October), the level of GL and polyunsaturated fatty acids (PUFA) sharply decreased. A high level of PUFA was observed from March to July and in November. In August and October, the same as in the spring, the proportion of saturated fatty acids (FA) was great. The content of chlorophylls from March to November varied from 20.3 to 26.9%, and the level of carotenoids — from 10.7 to 16.1%. Total content of PSP was relatively high in March and in August–September. Free sterols accounted for 3.4–7.3% of total lipids; their proportion was greater in spring than in summer and autumn.     

Biological activity of lipids and photosynthetic pigments of Sargassum pallidum C. Agardh

The biological activity of lipids and photosynthetic pigments of the kelp Sargassum pallidum (Turner) C. Agardh has been studied. Free fatty acids and their esters demonstrated considerable antimicrobial activity against bacteria (Staphylococcus aureus and Escherichia coli), yeast-like fungi (Candida albicans), and opportunistic pathogenic (Aspergilius niger) and phytopathogenic (Fusarium oxysporum, and Septoria glycines) fungi. Glyceroglycolipids and neutral lipids demonstrated moderate activity. Fucoxanthin and chlorophylls weakly suppressed the growth of microorganisms. None of the studied substances demonstrated activity against Ehrlich’s carcinoma. It was shown that the season of weed harvesting affected both antimicrobial and hemolytic activities of different lipids due to changes in their fatty acid composition.     

Antimicrobic and hemolytic activity of low-molecular metabolits of brown seaweed <Emphasis Type="Italic">Laminaria cichorioides</Emphasis> (Miyabe)

Antimicrobial and hemolytic activity of ethanol extract of brown seaweed Laminaria cichorioides (Miyabe), its lipophilic fractions, various classes of substances of lipophilic fraction, such as chlorophylls, fucoxanthin, monogalactosyldiacylglycerols, digalactosyldiacylglycerols, sulfoquinovosyldiacylglycerols, and fatty acids were investigated. The antimicrobial activity was studied by means of yeast cells Safale S-04 and Candida albicans KMM 455, fungi Aspergillus niger KMM 4634 and Fusarium oxysporum KMM 4639, bacteria Staphylococcus aureus ATCC 21027 (gram-positive) and Escherichia coli ATCC 15034 (gram-negative) which demonstrated selective sensitivity to the studied substances. Hemolytic activity was investigated at concentrations of substances in the range of 0.2–200 μg/ml at different pH of erythrocyte suspension. All investigated substances caused hemolysis. The dependence of hemolytic activity of substances on pH of media was determined.     

Seasonal variation in phenolic composition, antibacterial and antioxidant activities of Ulva rigida (Chlorophyta) and assessment of antiacetylcholinesterase potential

The phenolic composition and antibacterial and antioxidant activities of the green alga Ulva rigida collected monthly for 12 months were investigated. Significant differences in antibacterial activity were observed during the year with the highest inhibitory effect in samples collected during spring and summer. The highest free radical scavenging activity and phenolic content were detected in U. rigida extracts collected in late winter (February) and early spring (March). The investigation of the biological properties of U. rigida fractions collected in spring (April) revealed strong antimicrobial and antioxidant activities. Ethyl acetate and n-hexane fractions exhibited substantial acetylcholinesterase inhibitory capacity with EC₅₀ of 6.08 and 7.6 μg mL^?1, respectively. The total lipid, protein, ash, and individual fatty acid contents of U. rigida were investigated. The four most abundant fatty acids were palmitic, oleic, linolenic, and eicosenoic acids.     

Biological activity of metabolites of the herb <Emphasis Type="Italic">Kalanchoe diagremontania</Emphasis> (Hamet de la Bathie) Jacobs et Perr

In this study we investigated the hemolytic, antimicrobial, and phytoregulatory activity of various classes of lipids (triacylglycerols, free fatty acids (FFA), the glyceroglycolipids monogalactosyl diacylglycerol (MGDG), sulfoquinovosyl diacylglycerol (SQDG)), sterols, all of them were obtained from the medical herb Kalanchoe diagremontiana, and also pigments, phenolic compounds (FC), polysaccharides, and ethanol extract (EE) of the herbal. It was established that EE, FC, FFA, and sterols display pH-dependent membranothropic activity. FFA showed antimicrobial activity and stimulated growth of buckwheat stalk sprouts. K. diagremontiana glyceroglycolopids did not display expressed biological activity. Caroteniods displayed pH-independent membranothopic action and antibacterial activity. Chlorophylls displayed antimicrobial action, but did not influence erythrocytes and buckwheat sprouts. Polysaccharides acted against the microorganisms Safale S-04, Candida albicans, Fusarium oxysperum and buckwheat sprouts.     

Seasonal variation in antifouling activity of crude extracts of the brown alga Bifurcaria bifurcata (Cystoseiraceae) against cyprids of Balanus amphitrite and the marine bacteria Cobetia marina and Pseudoalteromonas haloplanktis

Previous studies have demonstrated that macroalgae from Brittany (France) contain products with antifouling activity against marine bacteria, fungi, diatoms, seaweeds and mussels. Little is known regarding the ecological function of these compounds and insufficient attention has been paid to evaluating the possible temporal variation in antifouling activity. Studies of chemical defenses in both terrestrial and marine organisms suggest that organisms vary widely in the production of chemical defenses associated with physical (temperature, light) and biological (e.g. grazing pressure) factors, season and geographical location. The present study aimed to investigate the antifouling activity of crude extracts of monthly collections of the brown alga, Bifurcaria bifurcata, against two marine bacteria, Cobetia marina and Pseudoalteromonas haloplanktis, and cypris larvae of the barnacle, Balanus amphitrite. The toxicity of the extracts was determined with a B. amphitrite nauplius assay.The antimicrobial activity of the extracts was found to be subject to seasonal variation, with the highest level of activity recorded from samples collected between April and September. Results of the anti-settlement experiments showed that the extracts of B. bifurcata (when tested from 0 to 100 μg/ml) can be divided into three groups on the basis of their minimum inhibitory concentrations (MICs): (1) extracts from plants collected from September to March reduced settlement at nontoxic concentrations (50-100 μg/ml); (2) extracts from plants collected from April to July (which were the most active extracts) reduced settlement significantly when tested at >5 μg/ml, but were toxic at 100 μg/ml; (3) the extract prepared from plants harvested in August was inhibitory at >25 μg/ml, but was toxic at 100 μg/ml. Toxicity tests on nauplii showed that LC₅₀ values of samples from the September to March collections were >100 μg/ml, demonstrating that they were nontoxic to nauplii. In contrast, samples obtained from the April to August collections were toxic to nauplii; the most toxic ones being from algae collected in May (LC₅₀=55.6 μg/ml) and in June (LC₅₀=38.3 μg/ml).The antifouling activity of extracts thus reached a peak in summer corresponding to maximal values for water temperature, light intensity and fouling pressure. It remains to be investigated whether this activity has an ecological role in the alga.     

Growth, morphology and photosynthetic responses of Neochloris oleoabundans during cultivation in a mixotrophic brackish medium and subsequent starvation

The green microalga Neochloris oleoabundans is able to grow in both low and high salinity media and is largely studied for its capability to accumulate lipids under starvation. Moreover, N. oleoabundans is a mixotrophic alga, and then organic carbon addition can promote its growth. This research aims to study the morpho-physiological aspects, with a particular attention on the photosynthetic response, both during mixotrophic growth and starvation in brackish media, more sustainable than freshwater cultivation. In the first step, the alga was cultivated mixotrophically in a brackish medium added with an apple waste product; in the second one, cells were starved also to verify lipid induction. Results indicate that growth is highly promoted during the first week of mixotrophic cultivation, while photosynthetic pigments and lipids are over-produced during the following three weeks of cultivation. In parallel, in mixotrophic cultures the maximum PSII quantum yield was enhanced during the exponential phase of growth. Interesting changes affected the mixotrophic cultures with respect to the partitioning of absorbed light energy. Starvation of both 7-day-grown mixotrophic and autotrophic cultures caused growth inhibition, pigments and photosynthesis downshifting, and concomitantly promoted evident lipid synthesis.     

Structural analysis of a highly sulfated fucan from the brown alga Laminaria cichorioides by tandem MALDI and ESI mass spectrometry

Water-soluble polysaccharide fractions were extracted from the brown alga Laminaria cichorioides. Samples were collected monthly from May to October in Troitsa Bay (Japan Sea, Russia). Analysis showed that the content and monosaccharide composition of the fractions changed with the collection season. Fucoidan was isolated and purified from the most fucose-rich fraction, collected in July, and subjected to autohydrolysis to obtain fucooligosaccharides, suitable for mass-spectrometric analysis. Both ESIMS and MALDI-TOFMS analyses show that multisulfated (up to 3) fucooligosaccharides with polymerization degree n from 2 to 5, including mono- and disulfated-fucose residues, were the major products of autohydrolysis. The structural features of the fucooligosaccharides and their alditol derivatives were elucidated by tandem MALDI-TOFMS and ESIMS. The results obtained allowed us to conclude that fragments of the fucoidan, collected in July, were predominantly linked with a (1→3)-type of linkage and that sulfate groups occupied mostly C-2 or C-2/C-4 of the α-l-fucose residues.     

Pharmacognostic study of aerial parts of Baikal skullcap (<Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi)

A pharmacognostic study of aerial parts of Scutellaria baicalensis Georgi (Lamiaceae family) has been carried out. A merchandising analysis has been performed to determine the basic quality parameters of S. baicalensis. A chemical composition analysis has revealed the presence of organic acids, free carbohydrates, polysaccharides, amino acids, alkaloids, flavonoids, phenolic acids, anthocyanins, tannins, photosynthetic pigments, lipids, and triterpene compounds. Ethyl acetate and ethanol fractions, extracted from the aerial parts of S. baikalensis, have shown a significant antiradical activity.     

Separation of Chlorophylls c(1) and c(2) from Pigment Extracts of Pavlova gyrans by Reversed-Phase High Performance Liquid Chromatography

Chlorophylls c₁ and c₂ have been separated from total pigment extracts of the alga Pavlova gyrans Butcher using a reversed-phase high-performance liquid chromatography system. Pigments were separated on a 5 micrometer C₁₈ column (25 centimeters × 4.6 millimeters) using a gradient of methanol-acetonitrile-water. Other photosynthetic pigments were also well resolved by the system used. The separation system described may replace current thin layer chromatography methods for qualitative and quantitative determination of chlorophyll c species.     

Why do the galls induced by Calophya duvauae Scott on Schinus polygamus (Cav.) Cabrera (Anacardiaceae) change colors?

One of the galling herbivores associated to the superhost Schinus polygamus (Cav.) Cabrera (Anacardiaceae) is Calophya duvauae Scott (Hemiptera: Calophyidae). The galls are located on the adaxial surface of leaves and vary from red to green. The levels of their pigments were herein investigated in relation to age. Samples were collected between June 2008 and March 2009, in a population of S. polygamus at Canguçu municipality, Rio Grande do Sul, Brazil. Galls were separated by color, measured, dissected, and the instar of the inducer was determined. The levels of photosynthetic (chlorophyll a and b, total chlorophylls, and carotenoids) and protective pigments (anthocyanins) were also evaluated. Red galls were more numerous than the green ones, and the induction should occur preferentially on young leaves, but may also occur on mature leaves. Immature stages of C. duvauae were observed in all samples throughout the year, characterizing its life cycle as multivoltine. There was a significant correlation between the instar of the inducer and the size of the gall (r = 0.675, p < 0.001), with larger galls corresponding to more advanced instars. The ratio between red and green galls varied over the samples, with the highest (96%) and lowest (38%) frequency of red galls observed in September, and December 2008, respectively. The average amounts of chlorophyll b and total chlorophylls were 70% lower in the gall tissues when compared to non-galled portions of galled leaves. There is a notable reduction in the contents of all pigments in the galls when compared to non-galled leaves, especially for total anthocyanins in green galls. The red galls presumably had the constant stimuli of healthy gall inducers, whereas in green galls they died prematurely, due to the interference of parasitoids and inquilines. The alterations in gall structure and color were related to the gradual decreasing in galling stimuli.     

Study of photosynthetic characteristics of the Pyropia yezoensis thallus during the cultivation process

The photosynthetic characteristics of thalli of cultured Pyropia yezoensis strains collected in January, February, and March in seaweed cultivation area of South China Yellow Sea were studied. Results showed that the maximum quantum efficiency (F _v/F _m) of all P. yezoensis thallus collected at different times was 0.65. The actual quantum efficiency (ΔF/F _m′) of samples in January was the lowest of all samples, while the ΔF/F _m′ of samples in March was significantly higher than those in January and February. The increase of temperature and photosynthetic pigments ratios of phycoerythrin and chlorophyll a (PE/Chla) and phycocyanin and chlorophyll a (PC/Chla) from January to March may be the important reasons for the increase in light use efficiency of thallus; although the thallus in March was significantly thicker than in January which may have reduced the light energy absorbed by photosynthetic pigments, the increase of relative high energy use efficiency also helped to maintain the photosynthetic oxygen evolution rate in March. The thicker thallus also reduced photodamage, and the thallus area was increased obviously in March, so the growth rate of thallus in March was over 35 % higher than that in February. Our research indicates that the photosynthetic characteristics of P. yezoensis strains thalli have a close relationship with their growth stage and environmental factors especially temperature, and those photosynthetic characteristics are also reflected in the growth rate of the thalli.     

Alteration in growth and thylakoid membrane lipid composition of <Emphasis Type="Italic">Azolla caroliniana</Emphasis> under phosphate deficiency

The changes in the fresh biomass accumulation, photosynthetic and anthocyanin pigments, photosystem 2 (PS 2) activity, ultrastructure of chloroplast, total lipids and fatty acid composition of thylakoid membrane were followed in the aquatic fern Azolla caroliniana grown on medium either deficient or supplied with various phosphorus concentrations. The content of photosynthetic pigments and the anthocyanin/chlorophyll ratio increased significantly with increasing PO₄ ³⁻ concentration. Phosphate deficiency inhibited growth and PS 2 activity and decreased content of total lipids and phospholipids in isolated thylakoids. This was accompanied with a significant increase in the percentage of galalactolipids.     

Effect of UV-B and high visual radiation on photosynthesis in freshwater (nostoc spongiaeforme) and marine (Phormidium corium) cyanobacteria

Human activity is causing depletion of ozone in stratosphere, resulting in increased UV-B radiation and global warming. However, impact of these climatic changes on the aquatic organism (especially marine) is not fully understood. Here, we have studied the effect of excess UV-B and visible radiation on photosynthetic pigments, fatty acids content, lipid peroxidation, nitrogen content, nitrogen reductase activity and membrane proteins, induction of mycosporine-like amino acids (MAAs) and antioxidant enzymes superoxide dismutase (SOD) and ascorbate peroxidase (APX) in freshwater (Nostoc spongiaeform) and marine (Phormidium corium) cyanobacteria. UV-B treatment resulted in an increase in photosynthetic pigments in Nostoc and decrease in Phormidium, but high light treatment caused photobleaching of most of the pigments in both the species. Unsaturation level of fatty acids of both total and glycolipids remained unchanged in both the cyanobacteria, as a result of UV-B and high light treatments. Saturated fatty acids of total and glycolipids declined slightly in Nostoc by both the treatments. but remained unchanged in Phormidium. No changes in the unsaturated lipid content in our study probably suggested adaptation of the organism to the treatments. However, both treatments resulted in peroxidation of membrane lipids, indicating oxidative damage to lipids without any change in the level of unsaturation of fatty acid in the cell membrane. Qualitative and quantitative changes were observed in membrane protein profile due to the treatments. Cyanobacteria were able to synthesize MAAs in response to the UV-B treatment. Both treatments also increased the activities of SOD and APX. In conclusion, the study demonstrated induction of antioxidants such as SOD and APX under visible light treatment and screening pigment (MAAs) under UV-B treatment, which might protect the cyanobacteria from oxidative damage caused by high light and UV-B radiation.     

Seasonal changes in the content of lipids,fatty acids,and pigments in brown alga <Emphasis Type="Italic">Costaria costata</Emphasis>

We compared the content of total lipids, particular lipid classes, fatty acids (FAs), and pigments in the brown alga Costaria costata [Turn.] Saund (Laminariaceae) in different seasons: during algal active life (April–June) and in the beginning of their degradation (the end of July). Lipids comprised only a small part of algal extractable compounds (10.9–13.4%). Their higher content was observed in May, in the period of alga preparation to sporogenesis. Polar lipids, glyceroglycolipids (GL) and phospholipids (PL), comprised a great part of total lipids in spring months and June, whereas neutral lipids, in July. GL predominated in polar lipids in spring and summer. The highest content of GL was observed in May and PL in April. Storage lipids comprised a great part of lipids in July. The content of sterols was the highest in April and May. In summer months, the content of sterols decreased and remained on unchanged level until thallus degradation. Polyunsaturated FAs (PUFAs) comprised the most part of FAs. Their highest content was observed in April. The main part of PUFAs were those of ω-3 series. In July, the level of these PUFA decreased substantially. The levels of ω-6 PUFAs were approximately similar in spring and summer months. The lowest content of monounsaturated FAs was detected in April; in May and July; the relative content of these FAs increased sharply. We also detected seasonal changes in the content of pigments and the ratios between them.     

Pigment and lipid compositions of algal and bacterial communities in Ace Lake,Vestfold Hills,Antarctica

The compositions of carotenoids, chlorophylls and lipids at four depths in Ace Lake have been determined as a means of studying the vertical zonation of species in the lake and for comparison with the lipids found in the bottom sediments. The four major species of phytoplankton found in the lake were identified by electron microscopy. The most abundant phytoplankter was Pyramimonas gelidicola McFadden (Chlorophyta, Prasinophyceae) which occurred in greatest numbers at 10 m, the base of the oxylimnion. The pigments and lipids at this depth were mainly derived from this alga. At 11 m (the top of the anoxylimnion) only traces of lipids and pigments attributable to P. gelidicola were found, indicating only limited settling of algal cells through to the anoxylimnion, at least in summer. The pigments at 11 m were dominated by bacteriochlorophylls c derived from green photosynthetic bacteria Chlorobium spp. These pigments were also abundant at 23 m suggesting the presence of intact bacterial cells which had settled out from higher in the water column. Major non-polar lipid classes in the sediments included sterols, alcohols, hydrocarbons and an unusual suite of very long-chain unsaturated ketones and esters which have not previously been reported from antarctic environments. Several novel compounds, not found previously in either sediments or organisms, are reported. These include tri- and tetra-unsaturated straight-chain C₃₉ methyl ketones and C₄₀ ethyl ketones and the methyl ester of a tetra-unsaturated straight-chain C₃₆ fatty acid. The distributions of lipids in the sediment were markedly different from those in the water column indicating extensive bacterial degradation and recycling of labile lipids.     

Antimicrobial activity of the toxin VdTX-I from the spider Vitalius dubius (Araneae,Theraphosidae)

BackgroundCurrently there is an urgent need to develop new classes of antimicrobial agents with different mechanisms of action from conventionally antibiotics used for the control of pathogenic microorganisms. The acylpolyamine called VdTX-I was isolated from the venom of the tarantula Vitalius dubius, and first described with activity as an antagonist of nicotinic cholinergic receptors. The main objective of this study was to investigate the antimicrobial activity found in the venom of the spider, with emphasis on the toxin VdTX-I.MethodsAntimicrobial assays were performed in 96 well plates culture against 14 micro-organisms (fungi, yeasts and bacteria), which were tested concentrations from 0.19 to 100 μM of VdTX-I. After qualitative analysis, dose-response curve assays were performed in bacterial kill curve using MTT reagent and hemolytic assay.ResultsThe antimicrobial activity of the VdTX-I toxin was observed in 12 tested species of Candida, Trichosporiun, Staphylococcus and Micrococcus. The toxicity had a dose-response at 3.12 µM – 100 μM in Candida albicans, Candida guillermondii, Micrococcus luteus and Escherichia coli. VdTX-I took about 5 min to inhibit bacterial growth, which was faster than streptomycin. The toxin showed no hemolytic activity between 0.19 and 100 μM. At 2.5 µg/mL of toxin it was observed no growth inhibition against a mammalian cell lineage.ConclusionsThe VdTX-I toxin has a significant antimicrobial activity, with broad spectrum, and is experimentally inert to mammalian blood cells.General SignificanceThis paper explores the antimicrobial potential of the spider toxin VdTX-I, which can provide a new model to design new antimicrobial drugs.     

Evidence of reproductive cost in the triphasic life history of the red alga Gracilaria chilensis (Gracilariales,Rhodophyta)

The extent of changes in basic physiological and demographic traits associated with reproduction was investigated in the highly cultivated haploid–diploid red alga, Gracilaria chilensis. Sixty individuals bearing vegetative and reproductive fronds collected in the natural population of Niebla (39°52′?S, 73°23′?W), in Chile, were cultivated under controlled culture conditions. Our results demonstrated that vegetative fronds have a higher survival rate and a better growth rate than reproductive ones irrespective of the type of individual analyzed (male gametophyte, female gametophyte, and tetrasporophyte). Moreover, the reproductive fronds clearly showed a decrease in photosynthetic activity compared to non-reproductive ones. In males and tetrasporophytes, the photosynthetic reduction in reproductive individuals could be explained by a physical effect of reproductive structure development as well as spores release, disrupting the continuity of the photosynthetic cortical tissues. Translocation of photoassimilates from nearby vegetative tissue or the previous accumulation of photosynthetic products seems to be a prerequisite for reproductive structure development in this species. Altogether, these results document for the first time in G. chilensis that reproduction has a strong physiological effect on male, female, and tetrasporophyte fronds. This trade-off between reproduction, growth, and survival suggest the existence of reproductive costs in the life history of G. chilensis.     

Identification and target-modifications of temporin-PE: A novel antimicrobial peptide in the defensive skin secretions of the edible frog, Pelophylax kl. esculentus

A potent natural antimicrobial peptide named temporin-PE was identified and encoded from the skin secretions of Pelophylax kl. esculentus via “shotgun” cloning and LC-MS/MS fragmentation analysis. Target-modifications were carried out to further enhance the antimicrobial and anti-proliferative bioactivities, whilst decreasing the hemolytic effect. A range of bioassays demonstrated that replacing a proline with a tyrosine residue resulted in a loss of the bioactivity against Gram-negative bacteria, but dramatically improved the hemolytic and anti-proliferative activity, indicating the FLP- motif influences the hemolytic activity of temporins. Moreover, the coupling of TAT to the peptide dramatically improved its antimicrobial activity, indicating coupling TAT to these peptides could be considered as a potential tool to improve their antimicrobial activity. Overall, we have shown that targeted modifications of this natural antimicrobial peptide can adjust its bioactivities to help its development as an antibiotic or anti-proliferative agent.