Effects of culture conditions on production of antibiotically active metabolites by the marine alga Spyridia filamentosa (Ceramiaceae, Rhodophyta). I. Light

The effect of irradiance over the range 5 to 70 μmol photon m⁻² s⁻¹ on production of antibiotically active metabolites was assessed for male and female gametophytes and tetrasporophytes of the red alga Sphyridia filamentosa (Wulfen) Harvey in Hooker in culture. Whole-algal extracts and ten recognizable TLC-separable zones were assayed against five human microorganisms pathogenic to humans. For all experimental irradiance conditions, the ten TLC zones displayed activity against four of the microorganisms. The maximum number of TLC zones with activity under any of the culture conditions was six each for male and female Spyridia at 70 μmol photon m⁻² s⁻¹. Small changes in irradiance resulted both in different activities against specific microorganisms and degree of activity. The fact that every TLC zone showed differing activities at different light conditions or when extracted from different life history stages strongly suggests the presence of multiple antibiotic principals in individual TLC zones. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphological,palynological, seed‐coat surface and karyological studies of Hesperis bicuspidata and H. stellata (Cruciferae) from Turkey

The taxonomic delimitation of Hesperis bicuspidata (Willd.) Poir. and H. stellata F. Dvo?ák is problematic, and we therefore studied morphological, palynological, seed‐coat surface and karyological features of both species to determine their degree of similarity. The morphology was described using 13 characters, each based on ten measurements on different specimens. Hesperis stellata and H. bicuspidata both show large variation in vegetative and reproductive organs; petal length varies between 18 and 26 mm and petal width is 3–7 mm; the corolla is lilac, whitish lilac, violet, dark violet or white in color, and fruits of both species are generally glabrous or have very short bifurcate hairs. Pollen and seed morphology were examined by LM and SEM. Pollen of both species is prolate‐spheroid or subprolate, tricolpate and reticulate. Their exine structures are the same. Hesperis bicuspidata is diploid (2n=14) but different chromosome types were present in the two studied specimens. Hesperis stellata is tetraploid (2n=28) showing the same chromosome types as the samples of H. bicuspidata. Eighteen morphometrical characters of H. bicuspidata, H. stellata, H. pisidica and H. armena were analysed by ANOVA. Notes on ecology and distribution are also presented for H. bicuspidata. Based on the results, H. stellata is reduced to a synonym of H. bicuspidata.     

Effects of culture conditions on production of antibiotically active metabolites by the marine alga Spyridia filamentosa (Ceramiaceae, Rhodophyta). I. Light

The effect of irradiance over the range 5 to 70 μmol photon m-2 s-1 on production of antibiotically active metabolites was assessed for male and female gametophytes and tetrasporophytes of the red alga Sphyridia filamentosa (Wulfen) Harvey in Hooker in culture. Whole-algal extracts and ten recognizable TLC-separable zones were assayed against five human microorganisms pathogenic to humans. For all experimental irradiance conditions, the ten TLC zones displayed activity against four of the microorganisms. The maximum number of TLC zones with activity under any of the culture conditions was six each for male and female Spyridia at 70 μmol photon m-2 s-1. Small changes in irradiance resulted both in different activities against specific microorganisms and degree of activity. The fact that every TLC zone showed differing activities at different light conditions or when extracted from different life history stages strongly suggests the presence of multiple antibiotic principals in individual TLC zones. This revised version was published online in June 2006 with corrections to the Cover Date.     

Identification of vibriocidal compounds from medicinal plants using chromatographic fingerprinting

The aim of the present study was to investigate the vibriocidal activity of bark of Syzygium cumini, leaves of Lawsonia inermis, fruits of Terminalia bellerica and identify the bioactive compounds. The vibriocidal activity of plant extracts was determined in aqueous and organic solvents, and the minimum inhibitory concentration (MIC) against Vibrio spp. using the disk diffusion method was established. The chemical constituents of the plant extracts were analysed by thin layer chromatography (TLC), the vibriocidal compounds were determined by TLC-bioautography and were further confirmed by high performance liquid chromatography (HPLC). Significant inhibitory activity was observed with ethanol extract of plants against the test bacteria while less antibacterial activity was observed in acetone, methanol and aqueous extracts. The MIC of the plant extracts ranged between 2.5 and 20 mg/ml. The TLC, TLC-bioautography and HPLC analysis showed that gallic acid and tannin present in ethanol extracts of S. cumini, tannin present in L. inermis and gallic acid present in T. bellerica may be responsible for the vibriocidal activity. S. cumini, L. inermis and T. bellerica can be used for the treatment of gastroenteritis, diarrhoea and cholera diseases after detailed investigations. We also conclude that the plants rich in gallic acid and tannin can be used as an alternative to search for new vibriocidal drugs.     

植被类型对盐沼湿地空气生境节肢动物功能群的影响

2007年4-11月,在长江口崇明东滩盐沼湿地的芦苇带、海三棱藨草带和互花米草带设置固定样地,每月小潮期对空气生境的节肢动物进行了扫网取样调查。在此基础上,分析研究了盐沼湿地空气生境节肢动物功能群特征以及植被类型的影响,特别是对互花米草的生态效应进行了进一步讨论。调查期间共获得节肢动物标本3778头,分属2纲11目37科49种。根据不同种类的营养特征将其划分为植食性、捕食寄生性和腐食性三大功能群。其中,植食性功能群的种类、数量最为丰富,涉及1纲6目19科25种,物种数占总数的51.0%,个体数占总数的86.2%;捕食寄生性功能群次之,涉及2纲7目15科21种,物种数占总数的42.9%,个体数占总数的7.8%;腐食性功能群种类、数量最少,涉及1纲1目3科3种,物种数占总数的6.1%,个体数占总数的6.0%。不同植被带捕食寄生性功能群与植食性功能群均具有一定的"天敌跟随"特征,但主要表现在物种数上,而在个体数上的对应关系并不明显。不同植被带功能群的组成、多样性及月际变化特征存在一定差异,但是植被类型对功能群的影响并不显著。与已有研究结果不同,研究中外来种互花米草对空气生境的节肢动物并未表现出显著的负面影响,相应节肢动物功能群的物种数、个体数、多样性、月际变化等特征与其他植被带并没有显著差异。就植食性功能群而言,尽管互花米草带植食性功能群的个体数明显低于其它植被带,但是物种数并没有减少,相应的作用机理还有待进一步研究。     

Production of a novel and cold-active killer toxin by Mrakia frigida 2E00797 isolated from sea sediment in Antarctica

The psychrotolerant yeast Mrakia frigida 2E00797 isolated from sea sediment in Antarctica was found to be able to produce killer toxin against the pathogenic yeast (Metschnikowia bicuspidata WCY) in crab. When the psychrotolerant yeast was grown in the medium with pH 4.5 and 3.0% (wt/vol) NaCl and at 15°C, it could produce the highest amount of killer toxin against the pathogenic yeast M. bicuspidata WCY. The crude killer toxin activity against the pathogenic yeast M. bicuspidata WCY was the highest when it grew at 15°C in the assay medium with 3.0% (wt/vol) NaCl and pH 4.5. At temperatures higher than 25°C, the killing activity produced by M. frigida 2E00797 was completely lost and after the crude killer toxin was pre-incubated at temperatures higher than 40°C for 4 h, the killing activity was also completely lost. The killer toxin produced by M. frigida 2E00797 could kill only M. bicuspidata WCY, Candida tropicalis and Candida albicans among all the fungal species and bacterial species tested in this study.     

Isolation of heterothallic yeast strains ofMetschnikowia Kamienski and their mating reactions withChlamydozyma Wickerham spp

Isolation ofMetschnikowia bicuspidata var.australis in the haplophase from Antarctic waters, andM. bicuspidata var.zobellii in haplo-and diplophases at Chatham Is. N.Z., led to the study of mating reactions within theChlamydozyma - Metschnikowia complex. The results indicate the phylogenetic relationships between species. The plant-associatedCh. pulcherrima. Ch. reukaufii, andM. zygota are distinct species; when cross-mated they will conjugate but not produce asci. These three species are closely related toM. bicuspidata; when they are mated withM. bicuspidata and its varieties (var.australis and var.zobellii) asci are produced without spores. The taxonomic status ofM. bicuspidata and its varieties is based on less frequent formation of ascospores between than within taxa.The new varietyM. bicuspidata var.australis and the new combinationsM. zygota andM. bicuspidata var.zobellii are proposed.Contribution No. 925 from the Institute of Marine Sciences, University of Miami, Florida.     

Biologically Active Polypeptides and Hydrolytic Enzymes in Sea Anemones of Northern Temperate Waters

The content of biologically active polypeptides in aqueous and ethanol extracts of seven sea anemone species collected near Sakhalin Island (Sea of Okhotsk) and in Posyet Bay (Sea of Japan) was analyzed. Water extracts of the sea anemone Cribrinopsis similis showed the highest hemolytic activity, while ethanol extracts proved to have toxic properties. The levels of toxic and hemolytic activity of extracts of sea anemones inhabiting northern temperate waters were 2 to 3 orders of magnitude lower, compared to tropic species. The reason for this is likely to be the differences in the habitat conditions and biological traits of these animals. The water extracts of all species possessed proteolytic, phospholipase A2, and low DNAase activities, except Actinostola sp., whose aqueous extract contained a high activity alkaline DNAase. The species studied contained a wide range of proteinase inhibitors, O-glycosyl hydrolases (glycosidases and polysaccharide hydrolases). Water extracts of C. similis and Stomphia coccinea possessed the highest laminarinase activity. High activity of N-galactopyranosidase was found in water extracts of S. coccinea and Oulactis orientalis.     

Production,purification, and characterization of a novel killer toxin from <Emphasis Type="BoldItalic">Kluyveromyces siamensis</Emphasis> against a pathogenic yeast in crab

The yeast Kluyveromyces siamensis HN12-1 isolated from mangrove ecosystem was found to be able to produce killer toxin against the pathogenic yeast (Metschnikowia bicuspidata WCY) in crab. When the killer yeast was grown in the medium with pH 4.0 and 0.5% NaCl and at 25 °C, it could produce the highest amount of killer toxin against the pathogenic yeast M. bicuspidata WCY. The killing activity of the purified killer toxin against the pathogenic yeast M. bicuspidata WCY was the highest when it was incubated at 25 °C in the assay medium without added NaCl and pH 4.0. The molecular weight of the purified killer toxin was 66.4 kDa. The killer toxin produced by the yeast strain HN12-1 could kill only the whole cells of M. bicuspidata WCY among all the yeast species tested in this study. This is the first time to report that the killer toxin produced by the yeast K. siamensis HN12-1 isolated from the mangrove ecosystem only killed pathogenic yeast M. bicuspidata WCY.     

The toxicity and biological effect of Pedalium murex L. extracts on the tobacco cutworm,Spodoptera litura (Fabr.) larvae

Petroleum ether, acetone, water and aqueous extract of Pedalium murex L. (Pedalaceae) leaves, root and fruit were tested against fourth instar larvae of the tobacco cutworm, Spodoptera litura (Fabr.) under laboratory conditions using leaf dip method. Larval mortality; larval, pupal and adult periods; pupal weight, pupation and adult emergence; larval and pupal deformities of S. litura were recorded. All the tested solvent extracts of P. murex were effective against S. litura life stages by causing mortality in a dose dependent manner. However, the efficacy was more significant with respect to acetone (leaf and root) and petroleum ether (root) at higher concentrations (0.8%) which leads to 100% larval mortality. The water and aqueous extracts of root caused 86.6 and 88.0% larval mortality respectively at 4% concentration. Among the plant parts tested, root had more importance followed by leaf and fruit. Plant extracts extended the larval, pupal and adult periods; reduced the pupal weight, pupal and adult emergence and caused larval–pupal deformities. Total life time was highly prolonged in acetone extracts of P. murex root. Though all the extracts were found to have insecticide activity, acetone and petroleum ether extracts of P. murex root can be used as an effective alternative to modern synthetic insecticides. Bioactive principles from these extracts can be isolated, identified and integrated in S. litura management.     

Interspecific variation in desiccation survival time of Aedes (Stegomyia) mosquito eggs is correlated with habitat and egg size

Summary Survival times of eggs under three humidity conditions (42%, 68%, 88% RH) were investigated among Aedes (Stegomyia) mosquitoes from temperate and tropical zones (5 species and 20 geographical strains). This subgenus tends to occupy small aquatic sites as larvae, where desiccation resistance of eggs is necessary during habitat drought. Interspecific comparison showed that the egg survival time was correlated with egg volume and dryness of source locality, and probably with habitat. Aedes aegypti is associated most with arid climate and human-disturbed habitats — its large eggs survived the longest periods at all humidities. Aedes albopictus ranges from tropics to temperate zones and inhabits both disturbed and forest habitats — its eggs were less desiccation-resistant than A. aegypti eggs. The survival times for forest species eggs (A. riversi, A. galloisi, A. flavopictus) were variable at high humidities but at the lowest humidity were consistently shorter than for eggs of A. aegypti and A. albopictus.     

Chromatographic and Biological Screening of Chosen Species of Schisandraceae Family: Schisandra chinensis,S. rubriflora,S. sphenanthera,S. henryi and Kadsura japonica

HPLC and TLC profiling was carried out for leaf and fruit extracts of five Schisandraceae species: Schisandra chinensis, S. rubriflora, S. spehenanthera, S. henryi and Kadsura japonica. HPLC measurements confirmed presence of lignans and phenolic compounds in fruits and leaves of all tested species. The most abundant in lignans was S. chinensis fruit extract in which 15 compounds were detected (e. g.: schisandrol A, schisanhenol, γ-schisandrin, gomisin N). The effect-directed detection, i. e., TLC-direct bioautography against Bacillus subtilis, showed exceptionally high activity for S. chinensis and S. rubriflora fruit extracts. On the other hand, TLC-DB enzyme tests (α-glucosidase, lipase, tyrosinase and acetylcholinesterase (AChE) inhibition assays) showed that all fruit and leaf extracts have ability to inhibit the above-mentioned enzymes (except for the K. japonica fruit). The leaf extracts showed much stronger antioxidant activity than the fruit ones, which were assessed and compared using both TLC-direct bioautography and spectrophotometric measurements based on ABTS, DPPH and FRAP tests.     

Studies on the efficiency of different extraction procedures on the anti microbial activity of selected medicinal plants

Many doubts still persist even today when it comes to selection of the solvents for extracting the active constituents from various Indian medicinal plants. This study was aimed at assessing and establishing the best solvent for extracting the active constituents from 10 plant extracts. Thin layer chromatography (TLC) was used to separate and establish the active constituents present in each of the medicinal plants. Active constituents from each plant were extracted by using three different solvent systems namely diethyl ether, chloroform and hexane and were tested against three species of gram negative and three species of gram positive bacteria (Escherichia coli, Pseudomonas aureginosa, Streptococcus pneumoniae, Aeromonas hydrophila, Staphylococcus aereus, Bacillus cereus) by means of agar well diffusion assay. Studies on the antioxidant activity studies were also carried out for these plant extracts by using Diphenylpicryl-hydrazyl (DPPH) method. For the antimicrobial activity, the study revealed that among the selected plants, Azadiracta indica, Pongamia pinnata, Aloe barbadensis had the maximum antibacterial activity. Among the extraction procedures diethyl ether was found to be the best solvent that could be used for the extraction procedure. On the antioxidant activity part, Coleus amboinicus and Calotropis procera were found to have high antioxidant activity of 91.64% and 88.72% respectively and the further results are reported and discussed.     

Germination-Arrest Factor (GAF): 3. Determination that the herbicidal activity of GAF is associated with a ninhydrin-reactive compound and counteracted by selected amino acids

A novel, naturally-occurring herbicide (Germination-Arrest Factor, GAF), produced by Pseudomonas fluorescens WH6 and several related isolates of rhizosphere bacteria, irreversibly arrests germination of the seeds of a wide range of graminaceous species, including a number of important grassy weed species. GAF activity has been shown previously to be associated with a hydrophilic, low molecular weight compound that contains an acid group. In the present study, thin-layer chromatography (TLC) of extracts of WH6 culture filtrate demonstrated that GAF activity migrates on TLC plates with a particular ninhydrin-reactive compound. This compound was found to be present in GAF-producing P. fluorescens isolates and absent in P. fluorescens strains that lack the ability to produce GAF. Treatments, including mutagenesis, which resulted in the loss of GAF activity in culture filtrates from P. fluorescens WH6 were shown to result in the disappearance of this ninhydrin-reactive compound from extracts of WH6 culture filtrates or in alteration of its appearance on TLC chromatograms. The ninhydrin-reactivity of GAF indicates that it probably contains an amino group, as well as the acid group previously demonstrated, and suggests that GAF may be a small peptide or amino acid analog. Biological investigations motivated by this conclusion demonstrated that the effects of GAF in inhibiting the germination of seeds of annual bluegrass (Poa annua L.) could be counteracted by treatment with alanine or glutamine and, to lesser extent, by several other amino acids, suggesting that this compound may act by interfering with some aspect of amino acid metabolism or function.     

In Vitro Antimicrobial Activity of <Emphasis Type="Italic">Acacia catechu</Emphasis> and Its Phytochemical Analysis

Acacia catechu, commonly known as catechu, cachou and black cutch is an important medicinal plant and an economically important forest tree. The methanolic extract of this plant was found to have antimicrobial activities against six species of pathogenic and non-pathogenic microorganisms: Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The maximum zone of inhibition (20 mm) was found to be exhibited against S. aureus. For this organism the minimum bactericidal concentration (MBC) of the crude extract was 1,000 μg/ml. The extract was found to be equally effective against gram positive and gram negative bacteria. The antimicrobial activity of the extract was found to be decreased during purification. The chemical constituents of organic plant extracts were separated by thin layer chromatography (TLC) and the plant extracts were purified by column chromatography and were further identified by Gas chromatography–mass selection (GC–MS) analysis. The composition of A. catechu extract had shown major components of terpene i.e. camphor (76.40%) and phytol (27.56%) along with other terpenes in minor amounts which are related with their high antibacterial and antifungal properties.     

Ecological studies on the community of drifting seaweeds in the south-eastern coastal waters of Izu Peninsula, central Japan. II: Seasonal changes in plants showing maximum stipe length in drifting seaweed communities

The authors examined seasonal patterns in 20 sargas‐saceous species (maximum stipe length of ≥45 cm) from 902 patches of drifting seaweeds in the southeastern coastal waters of the Izu Peninsula, central Japan, between spring and autumn, 1991–1993. The first analysis, dealing with plants occurring for three consecutive years, examined the top three ranked species determined from monthly pooled means of frequency of appearance in these 3 years. The second analysis examined not only the top‐ranked species in monthly means in each year, but also the continuity of appearance of species among years. The third analysis was made from dendrogram analysis based on monthly samples from each year. The first and second analyses revealed three seasonally discernible changes. From April to June, dominance shifted from Sargassum horneri (Turner) C. Agardh to Sargassum yamamotoi Yoshida with a stable transition; in July, S. yamamotoi, Sargassum macrocarpum C. Agardh, Sargassum crispi‐folium Yamada and Sargassum piluliferum (Turner) C. Agardh appeared consistently in an unstable domination with low frequency of appearance by Sargassum nipponicum Yendo, Sargassum fulvellum (Turner) C. Agardh, S. macrocarpum or S. crispifolium; in August to October, there was a stable shift from S. macrocarpum to Sargassum micracanthum (Kützing) Endlicher and Sargassum ringgoldianum Harvey. In the third analysis, monthly samples from each year were divided into four groups, characterized using the top five ranks. This characterization indicated that the top‐ranked species shifted from S. horneri to S. yamamotoi, to S. macrocarpum and to S. micracanthum with the change of seasons. Because of an overlap in the characteristic species in these three analyses, seven species (S. horneri, S. micracanthum, S. yamamotoi, S. macrocarpum, S. ringgoldianum, S. nipponicum and S. crispifolium) were regarded as dominant species. Results are compared to our previous study and it is suggested that the similarity in the pattern of plant community during seasonal changes over the period from April to June and in July resulted from both stable and unstable changes, respectively, but discrepancies in the pattern of plant community during seasonal change from August to October were the result of differences in the frequency of appearance of S. ringgoldianum and S. macrocarpum in August 1991. These results indicated that the seasonal changes of dominant species in the plant community from April to October in this study area were periodic except in July.     

Speciation in the yeast genusMetschnikowia

Genetic studies were employed to rationalize speciation in the yeast genusMetschnikowia. Using haploid cultures derived parasexually or from isolated single ascospores, hybrids were produced between mostMetschnikowia taxa. The results provided strong evidence for the acceptance ofM. bicuspidata as type of the genus, and enabled clarification of the relationships among the recognized species. Speciation was based primarily on ascus and ascospore morphology, as classification based on physiological properties was shown to be ineffective.Metschnikowia bicuspidata var.californica var. nov. is described, and some possible evolutionary trends are discussed.Partial support for J. I. P. from a C.S.I.R.O., Australia, Overseas Postgraduate studentship is gratefully acknowledged.     

Mycorrhizal improvement in non-leguminous nitrogen fixing associations with particular reference toHippophaë rhamnoides L.

Summary The roots ofHippophaë rhamnoides which regularly bear actinomycete induced nodules when growing on Scottish sand dunes have also been found to support an endomycorrhizal association withGlomus fasciculatus. Ultrastructural and cytochemical studies carried out on the indigenous infections of establishedHippophaë mycorrhizal roots would support the postulate that transport is indeed occurring between the fungal symbiont and the host plant and vice versa in respect of phosphate and carbohydrate. Experiments using various inoculation regimes, demonstrated the significant improvement in the mycorrhizal/nodulated plants compared to the nodulated-only and the mycorrhizal-only plants with respect to plant growth, uptake of phosphate and nitrogenase activity, when grown in a medium poor in combined nitrogen and soluble phosphate. Preliminary work onAlnus andMyrica species growing in Central Scotland indicates that the mycorrhizae associated with these nodulated root systems exhibit a different interaction pattern which may be dependent on habitat type and associated angiosperm species.     

The intersection of ecological risk assessment and plant communities: an analysis of <Emphasis Type="Italic">Agrostis</Emphasis> and <Emphasis Type="Italic">Panicum</Emphasis> species in the northeastern U.S.

Ecological risk assessments for grass species with novel traits are advisable, or required, in order to identify potential environmental harms prior to large-scale cultivation. Credible risk assessments are built upon knowledge of the communities that could be negatively affected by crop-to-wild gene flow, new weeds, or invasive plants. This study focused on two cultivated grasses with different life histories: the exotic, weedy Agrostis stolonifera (creeping bentgrass) and the native Panicum virgatum (switchgrass). Vascular plant communities were analyzed in 190 transects (50 m) in ten habitat types across two ecoregions (inland and coastal) in the northeastern U.S. Ordination plots and dendrogram analysis showed clustering of inland plant community assemblages within habitat types, while coastal plant communities were similar across the habitats studied. Agrostis and Panicum species had unequal distribution across the habitat types and ecoregions. Agrostis species were more common in the inland ecoregion and habitats receiving moderate management or disturbance events. In both ecoregions, A. stolonifera had high co-occurrence values with other exotic Agrostis species, suggesting potential for interspecific gene flow. P. virgatum was most common in inland roadside and wasteland habitats, but was distributed equally in the three coastal habitats. Co-occurrence between P. virgatum and congenerics was infrequent, although one transect had both P. virgatum and the state-listed coastal species Panicum amarum. This is the first study to characterize Agrostis and Panicum plant communities and distribution providing the basis for ecological risk assessments, coexistence-strategies, and geographic exclusion zones.     

Lignicolous fungi from northern Serbia as natural sources of antioxidants

As a result of an interest in natural derived metabolites, lignicolous fungi have taken on great importance in biochemical investigations. In the present study, antioxidative screening analyses have included in vitro testing of different extracts (aqueous, methanol, chloroform) of four fungal species using three different assays: Fe²⁺/ascorbate-induced lipid peroxidation by TBA assay, the neutralisation of OH· radicals and the radical scavenging capacity with the DPPHk]assay. TLC analysis confirmed the existance of phenolics in the extracts, but also indicates the presence of some other compounds. The obtained results indicate that MeOH extracts manifested a degree of activity higher than that of CHCl₃ extracts. With respect to antioxidative activity, the extracts can be ranged in the following declining order: G. lucidum, G. applanatum, M. giganteus and F. velutipes. These results suggest that analyzed fungi are of potential interest as sources of strong natural antioxidants that could be used in the food industries and nutrition.