Effects of enhanced UV-B radiation in the field on the concentration of phenolics and chlorophyll fluorescence in two boreal and arctic–alpine lichens

Lichens constitute a prominent part of the vegetation at high latitudes and altitudes, but the effects of UV-B radiation on these symbiotic organisms are not well known. In a northern boreal site (Abisko, northern Sweden), the usnic acid-producing lichens Flavocetraria nivalis and Nephroma arcticum were exposed to enhanced UV-B radiation, corresponding to 25% ozone depletion, for two and one growing seasons, respectively. They were compared with lichens grown under ambient UV-B and harvested fresh from the field. The treated thalli of F. nivalis had been transplanted from a site 24 km from the treatment site. From this source locality, untreated thalli were also harvested. Enhanced UV-B did not affect concentrations of usnic acid and the two depsides phenarctin and nephroarctin. A gradual decline of usnic acid, probably coupled to unusually long periods of dry, sunny weather, was observed both under enhanced and ambient UV-B and in untreated thalli. Photosystem II efficiency in both species was slightly reduced by enhanced UV-B. However, differences between seasons were larger than differences between treatments, which indicate that UV-B effects are minor in comparison to other climatic variables. Concentrations of UV-B-absorbing phenolics in lichens do not show a simple relationship to UV-B dose and therefore cannot be used as bioindicators of UV-B levels.     

Ultrastructural,morphological, and molecular characterization of Colaconema infestans (Colaconematales,Rhodophyta) and its host Kappaphycus alvarezii (Gigartinales,Rhodophyta) cultivated in the Brazilian tropical region

Endophytic and epiphytic infections have caused serious problems for Kappaphycus farmers, such as reduction in biomass production and decrease in the yield and quality of carrageenan. During environmental monitoring from January 2011 to December 2012, along Pitimbu Beach, Paraíba State, northeastern Brazil, drifting thalli of Kappaphycus alvarezii (Gigartinales, Rhodophyta) were detected with red spots, apparently caused by epiphytic/endophytic infections. Therefore, drifting thalli of K. alvarezii farmed along the northeastern Brazilian coast were cultured in the laboratory and submitted to molecular and morphological analyses to identify and characterize the causative agent and its effects on the cellular structure and ultrastructure of the host alga K. alvarezii that was found to be infected by the endophyte Colaconema infestans (Colaconematales) identified through morphological and rbcL molecular evidence. Infected thalli of K. alvarezii were processed and analyzed through light, transmission electron, and scanning electron microscopy. Alterations were observed in morphology and cellular organization, including structural changes of chloroplasts and decrease in floridean starch grains, along with increased cell wall thickness. Therefore, while no outbreak has been reported, the discovery of C. infestans infection in drifting thallus of K. alvarezii suggests a potential threat to its cultivation that should be monitored.     

Vertical concentration gradients of heavy metals in Cladonia lichens across different parts of thalli

Certain lichens of the genus Cladonia are effective heavy-metal-tolerant colonisers of strongly contaminated and disturbed sites. Among them, Cladonia cariosa, Cladonia pyxidata and Cladonia rei are the major components of specific cryptogamic assemblages proven to be bioindicators of soil pollution. This study examines the bioaccumulation capacity and heavy metal accumulation pattern of these species in the context of element concentration levels in various parts of their thalli at various vertical distances from the ground. The content of Zn, Pb, Cd, As and Cu in primary squamules, lower and upper parts of secondary thalli (podetia), and fruiting bodies (apothecia), as well as the corresponding substrate, was analysed using the AAS method. The substrate turned out to be the main source of heavy metals in the examined Cladonia lichens. Element accumulation in particular parts of thalli greatly depends on metal enrichment in the immediate vicinity while Cu/Zn ratios for both substrate and lichen samples were very low and comparable within the species. Concentration levels in thalli usually decrease significantly with distance from the substrate. The exception is copper, which content was frequently higher in apothecia than in the upper parts of podetia. Low bioaccumulation factors calculated for the examined Cladonia specimens classified these lichens as weak accumulators of heavy metals. Even given an extremely high level of contaminants in the substrate, the upper parts of thalli are not greatly affected. Consequently, fruticose and erect growth form, in combination with low accumulation capacity and a remarkable decrease in metal content along a vertical gradient, may be an important attribute of Cladonia lichens in the colonisation of a highly contaminated substrate. The content of elements differs significantly between particular parts of Cladonia thalli; this should be taken into account whenever burdens of heavy metals are used as indicators in biomonitoring studies.     

Response of the lichen-eating moth <Emphasis Type="Italic">Cleorodes lichenaria</Emphasis> larvae to varying amounts of usnic acid in the lichens

Lichens are characterized by a great variety of secondary metabolites. The function of these substances remains partly unknown. In this study, we propose that some of these metabolites may expel insect herbivores. To test this hypothesis, we reared larvae of the lichenivorous moth Cleorodes lichenaria on three selected lichens, Cladonia arbuscula subsp. mitis, Usnea hirta, and Usnea dasypoga. In experimental setup, the secondary metabolite usnic acid was removed from the lichens with acetone prior to feeding, whereas a control was left untreated. On all three lichens, removal of usnic acid from the lichens using acetone significantly prolonged survival of larvae and increased their viability. Larvae reared on control lichens contained significantly more usnic acid than those reared on treated lichens, both in their biomass and their faeces. These results support the hypothesis that usnic acid serves as a repellent against insect feeding, besides its well established functions of UV protection and antimicrobial properties.     

UV triggers the synthesis of the widely distributed secondary lichen compound usnic acid

Synthesis of the cortical dibenzofuran derivative usnic acid and the medullary depsidone salazinic acid was studied in Xanthoparmelia stenophylla thalli from which the compounds had been removed by acetone rinsing prior to a 21-day field experiment with UV absorbing and transmitting screens. Natural levels of ultraviolet radiation clearly induced the re-synthesis of usnic acid. The re-synthesis was boosted by the addition of ribitol, the carbohydrate delivered from the Trebouxia photobiont to the mycobiont. Salazinic acid was also weakly induced by UV. Re-synthesis was relatively low, up to 2.5 and 3.1% of start values for usnic and salazinic acid, respectively. However, given that the natural content of both compounds was high, constituting 12% of thallus dry weight, the absolute amounts of lichen compounds re-synthesised were not so small. We also studied the extractability of nine extracellular lichen compounds in three species X. stenophylla, Hypogymnia tubulosa, and Vulpicida pinastri, and found two distinct fractions of cortical compounds, one major that was completely extractable from living lichens and one minor that was only extractable with grinding. Medullary compounds were completely extracted without grinding. These findings did not influence the relative differences between treatments in our experiment, but may be of importance for future assessments of, e.g., quantitative studies of extracellular lichen compounds.     

QUANTITATIVE VARIATION IN VULPINIC AND PINASTRIC ACIDS PRODUCED BY TUCKERMANNOPSIS PINASTRI (LICHEN-FORMING ASCOMYCOTINA,PARMELIACEAE)

Tuckermannopsis pinastri is a lichen species found commonly on rocks and tree branches in boreal and alpine habitats in the northern United States. Members of this species produce three yellow-pigmented phenolic compounds: usnic, pinastric, and vulpinic acids. The objective of our study was to quantify the variation in concentration of the latter two of these compounds in relation to substrate factors, chlorophyll content, and thallus size. Using high-performance liquid chromatography, we analyzed 120 thalli of T. pinastri collected randomly from a single large population located at Spruce Knob, West Virginia. Although individuals were sampled from both tree and rock substrates that differed markedly in light intensity, these environmental factors were not correlated with observed variations in vulpinic or pinastric acid concentrations. Instead, compound concentrations were correlated most closely with thallus size, with small rather than large thalli having the highest concentrations of the two compounds. Small thalli did not have higher concentrations of chlorophylls than large thalli, however, which suggests that the rate of production of secondary compounds by the fungus in T. pinastri is independent of algal biomass. Inasmuch as lichen secondary compounds serve a defensive role against microorganisms and herbivores, our results suggest that small, juvenile thalli are better defended than more mature thalli.     

Differences in surface-dwelling beetles of grasslands invaded and non-invaded by goldenrods (Solidago canadensis,S. gigantea) with special reference to Carabidae

We evaluated surface-dwelling Coleoptera with special reference to ground beetles (Coleoptera: Carabidae) using pitfall traps across fourteen stands of grasslands invaded and non-invaded by invasive goldenrods (Solidago canadensis L. and S. gigantea Ait.) over a 3 year period. We analysed differences in assemblages of invaded and non-invaded grasslands and tested responses of surface-dwelling beetles and carabids to invasion of goldenrods. We identified 29 Coleoptera families and 91 Carabidae species. Solidago invaded grasslands showed significantly higher activity-abundance of rove and carrion beetles and supported greater diversity and significantly higher evenness of surface-dwelling Coleoptera and the number of sampled families and individuals was higher too. We found lower taxonomic richness and significantly lower activity-abundance of carabids across goldenrods stands. Several less common Carabidae species and significantly higher representation of stenotopic brachypterous habitat specialists were also observed within invaded stands. We confirmed that differences in plant cover connected with invasion of goldenrods, soil moisture and abandonment of invaded habitats are the driving mechanisms of changes in surface-dwelling Coleoptera and ground beetles assemblages composition across Solidago invaded grasslands. Overall, changes of grassland biotopes connected with invasion of goldenrods significantly alter Coleoptera families and Carabidae assemblages, but not necessarily reduce diversity.     

Penicillium strains isolated from Slovak grape berries taxonomy assessment by secondary metabolite profile

The secondary metabolite profiles of microfungi of the genus Penicillium isolated from samples of grape berries collected in two different phases during two vegetative seasons in Slovakia is described to assess the taxonomy. Three Slovak vine regions have been selected for this study, based on their climatic differences and national economic importance. Cultures of microfungi isolated from berries were incubated on different selective media for macro and micromorphology identification. The species Penicillium brevicompactum, Penicillium crustosum, Penicillium chrysogenum, Penicillium expansum, Penicillium palitans and Penicillium polonicum were identified according to growth and morphology. The related strains were found to produce a broad spectrum of fungal metabolites, including roquefortine C, chaetoglobosin A, penitrem A, cyclopeptin, cyclopenin, viridicatin, methylviridicatin, verrucofortine, secalonic acid D, cyclopiazonic acid, fumigaclavine and mycophenolic acid. Chemotaxonomy was performed using high-performance liquid chromatography (HPLC) and mass spectrometry (MS). Dried grape berries were also analyzed allowing to assess the presence of patulin, roquefortine C and penicillic acid; this last one has been identified in dried berries but not in vitro.     

Chimpanzees of Sapo Forest,Liberia: Density,nests, tools and meat-eating

Two months were spent surveying for chimpanzees (Pan troglodytes verus) in the Sapo Forest, eastern Liberia. The population density, as estimated from the number of nests found on transects, appears lower than that in other forest sites. Nests were more similar to those of other forest-living chimpanzees than of a savannah population. Most nests were found in areas of primary forest. Evidence was found of the chimpanzees using stones as hammers to break open four species of nut; there may be differences in materials and techniques used in this behaviour between Sapo chimpanzees and those in Tai Forest, Ivory Coast. Analysis of faeces revealed that Sapo chimpanzees eat meat.     

Freshwater Crustacea (Cladocera,Copepoda) of Iceland: taxonomy,ecology, and biogeography

Of the many types of freshwater bodies across Iceland (e.g., lakes, springs, rivers, and ponds), greater effort has been invested in researching the freshwater Crustacea (Cladocera, Copepoda) of more permanent, larger, and deeper water bodies than on smaller or more ephemeral sites. To address this, we described the fauna of 12 shallow freshwater bodies distributed from the coast to the central highlands of Iceland. We identified 16 species in 11 genera belonging to six families of Cladocera, and 12 species in eight genera belonging to four families of Copepoda. Five of the species we identified (Alona werestschagini, Cyclops vicinus, Daphnia cristata, Diacyclops abyssicola, and Heterocope borealis) represent new distribution records for Iceland, increasing the number of species now known from this region to 34 Cladocera and 38 Copepoda taxa. Additionally, we discuss the taxonomy of some species with doubtful taxonomical status. Six crustacean taxocenes are described, each characterized by the dominance of different taxa, with bottom sediment characteristics best explaining species assemblage structure. We evaluated the relationships between Icelandic Cladocera and Copepoda faunas and those of the adjacent Svalbard, Faroe, and Shetland Islands, Greenland, and the mainland Norway. The taxonomic composition of the Icelandic fauna is dominated by widely distributed Holarctic, and secondarily Palaearctic and Nearctic species, and is more similar to the faunas of the major North Atlantic islands (64.2–71.8 % similarity) than it is to that of continental Norway.     

Secondary Metabolites of Micromycetes in Plants of the Family Fabaceae,Genus <Emphasis Type="Italic">Trifolium</Emphasis>

The component composition and content of mycotoxins in perennial grasses of five species of the genus Trifolium, selected from natural biocenoses in different periods of vegetation, were studied. In the terrestrial parts of plants, the permanent presence of alternariol, cyclopiazonic acid, and emodin was shown. It was noted that differences in contamination are most clearly expressed in meadow clover Trifolium pratense L. and white clover Trifolium repens L., while alsike clover Trifolium hybridum L. occupies an intermediate position. It was found that zigzag clover Trifolium medium L. and mountain clover Trifolium montanum L., morphologically close to meadow clover, practically did not differ in the composition of toxic metabolites. The ways of formation of metabolic equilibrium in plants with participation of microscopic fungi are discussed.     

Molluscicidal activity of the Puerto Rican Weed,Solatium nodiflorum,against snail hosts ofFasciola hepatica

After screening 200 species of Puerto Rican plants, Solanum nodiflorumwas selected for comprehensive laboratory evaluation as a source of natural molluscicide. All parts of this plant were found toxic to the snails Fossaria (Lymnaea) cubensis, Lymnaea columella, Biomphalaria glabrata,and Physa cubensis.No toxicity was found against Marisa cornuarietisand Tarebia granifera. The toxicant was not affected by pH and dry storage. There was a direct correlation between temperature and molluscicidal activity. The plant is easy to find locally and could be developed into cheap, safe means for controlling both Schistosomaand Fasciolasnail hosts in Puerto Rico.     

Occurrence of the plant growth regulator jasmonic acid in plants

The natural occurrence of jasmonic acid and its methyl ester in plants has been studied using different methods such as GC, GC-MS, HPLC, radioimmunoassay, and bioassay. Jasmonic acid was detected in several Leguminosae plants and a number of species belonging to nine other Angiospermae families. Highest amounts occurred in fruit parts, especially the immature pericarp, but it was found also in flowers and vegetative plant parts, e.g. leaves, stems, and germs. Young apple fruits contain both jasmonic acid and methyl jasmonate, and in Douglas fir, the only Gymnospermae species studied, only the methyl ester could be detected. Jasmonic acid is discussed as an endogenous plant growth regulator widely distributed in higher plants.     

A new circumscription of the lichen genus <Emphasis Type="Italic">Nephromopsis</Emphasis> (Parmeliaceae,lichenized Ascomycetes)

The phylogeny of the cetrarioid lichens with bifusiform spermatia and dorsiventral thalli which contain usnic acid is reanalysed using three parts of the genome, ITS rDNA, β-tubulin and GAPDH sequences. Molecular data from five cetrarioid species are presented for the first time, and 13 new sequences are combined with sequences from the gene bank to delimit the genus Nephromopsis. A monophyletic clade of Nephromopsis, Tuckneraria, ‘Cetraria’ leucostigma and ‘C.’ melaloma is identified and circumscribed as one genus, Nephromopsis, which now includes 19 species. Four new combinations are presented. A key to the species is provided.     

Are “universal” DNA primers really universal?

“Universal” DNA primers LCO 1490 and HCO 2198 were originally designed from three coding and six anticoding strands by comparing highly conserved regions of mitochondrial cytochrome c oxidase subunit I (COI) genes across 15 taxa. These primers have been successful in amplifying a 710-bp fragment of highly conserved regions of the COI gene for more than 80 invertebrate species from 11 phyla. In the present study, 130,843 variations were reviewed in the primer region of mitochondrial molecular markers by comparing 725 COI sequences from the kingdom Animalia. It was found that, for 177 invertebrate species, the forward primer (LCO 1490) showed only four conserved regions, compared to 12 in the original study. For ascidians, fungi and vertebrates, it showed approximately 50 % conserved regions, dropping to one conserved region for echinoderms. However, the reverse primer (HCO 2198) was highly conserved across 725 COI primer sequences. A similar pattern was observed in amino acid distributions. There was a significant difference in the means of base pair differences from the level of family, genus and species for LCO 1490 [analysis of variance (ANOVA), F _6,188?=?8.193, P?ANOVA, F _6,77?=?2.538, P?相似文献   

The potential hazards of Aspergillus sp. in foods and feeds,and the role of biological treatment: A review

The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.     

Lichen Secondary Metabolites in Flavocetraria cucullata Exhibit Anti-Cancer Effects on Human Cancer Cells through the Induction of Apoptosis and Suppression of Tumorigenic Potentials

Lichens are symbiotic organisms which produce distinct secondary metabolic products. In the present study, we tested the cytotoxic activity of 17 lichen species against several human cancer cells and further investigated the molecular mechanisms underlying their anti-cancer activity. We found that among 17 lichens species, F. cucullata exhibited the most potent cytotoxicity in several human cancer cells. High performance liquid chromatography analysis revealed that the acetone extract of F. cucullata contains usnic acid, salazinic acid, Squamatic acid, Baeomycesic acid, d-protolichesterinic acid, and lichesterinic acid as subcomponents. MTT assay showed that cancer cell lines were more vulnerable to the cytotoxic effects of the extract than non-cancer cell lines. Furthermore, among the identified subcomponents, usnic acid treatment had a similar cytotoxic effect on cancer cell lines but with lower potency than the extract. At a lethal dose, treatment with the extract or with usnic acid greatly increased the apoptotic cell population and specifically activated the apoptotic signaling pathway; however, using sub-lethal doses, extract and usnic acid treatment decreased cancer cell motility and inhibited in vitro and in vivo tumorigenic potentials. In these cells, we observed significantly reduced levels of epithelial-mesenchymal transition (EMT) markers and phosphor-Akt, while phosphor-c-Jun and phosphor-ERK1/2 levels were only marginally affected. Overall, the anti-cancer activity of the extract is more potent than that of usnic acid alone. Taken together, F. cucullata and its subcomponent, usnic acid together with additional component, exert anti-cancer effects on human cancer cells through the induction of apoptosis and the inhibition of EMT.     

Rhodopseudomonas globiformis,sp. n., a new species of the Rhodospirillaceae

Enrichments of pH: 5.1, inoculated from a warm, acidic sulfur spring of the Yellowstone Park, yielded purple red cultures of a mobile, spherical organism belonging to the Rhodospirillaceae, described herein as a new species Rhodopseudomonas globiformis. Under favourable conditions, the cells are 1.6–1.8 μm in diameter, smaller and larger cells may occur. The photopigments consist of bacterio-chlorophyll a_P and new aliphatic methoxylated ketocarotenoids. The organism grows either under anaerobic conditions in the light or under microaerophilic conditions in the dark. Biotin, p-aminobenzoic acid and a source of reduced sulfur are required as growth factors. Gluconate, mannitol, fructose and ethanol are the best carbon sources at a pH of 4.9. Growth is inhibited by low concentrations of sulfide.     

Study of effect of substitution of the penultimate amino acid residue on expression,structure, and functional properties of Yersinia pseudotuberculosis OmpY porin

The purpose of the study was to compare the expression of two Yersinia pseudotuberculosis proteins, wild-type porin OmpY and the mutant porin OmpY designated as OmpY-Q having the uncharged amino acid residue Gln instead of positively charged Arg at the penultimate position in the same heterologous host. According to the literature, a similar substitution (Lys to Gln) of the penultimate amino acid residue in Neisseria meningitidis porin PorA drastically improved the assembly of the protein in the E. coli outer membrane in vivo. Site-directed mutagenesis was used to replace Arg by Gln (R338Q) in OmpY, and the conditions for optimal expression and maturation of OmpY-Q were selected. It was found that the growth rates of E. coli strains producing OmpY and OmpY-Q and the expression levels of the porins were approximately equal. Comparative analysis of recombinant OmpY and OmpY-Q did not show significant differences in structure, antigenic, and functional properties of the porins, or any noticeable effect of the R338Q substitution in OmpY on its assembly in the E. coli outer membrane in vivo. The probable causes of discrepancies between our results and the previous data on porin PorA are discussed considering the known mechanisms of biogenesis of porins at the periplasmic stage.