Sophorolipids are carbohydrate-based, amphiphilic biosurfactants that are of increasing interest for use in environmentally benign cleaning agents. Sophorolipid production was tested for 26 strains ...representing 19 species of the Starmerella yeast clade, including Starmerella bombicola and Candida apicola, which were previously reported to produce sophorolipids. Five of the 19 species tested showed significant production of sophorolipids: S. bombicola, C. apicola, Candida riodocensis, Candida stellata and a new species, Candida sp. NRRL Y-27208. A high-throughput matrix-assisted laser desorption/ionization-time of flight MS assay was developed that showed S. bombicola and C. apicola to produce a lactone form of sophorolipid, whereas C. riodocensis, C. stellata and Candida sp. NRRL Y-27208 produced predominantly free acid sophorolipids. Phylogenetic analysis of sequences for the D1/D2 domains of the nuclear large subunit rRNA gene placed all sophorolipid-producing species in the S. bombicola subclade of the Starmerella clade.
Magic, sorcery and witchcraft are among the most common themes of the great medieval Icelandic sagas and poems, the problematic yet vital sources that provide our primary textual evidence for the ...Viking Age that they claim to describe. Yet despite the consistency of this picture, surprisingly little archaeological or historical research has been done to explore what this may really have meant to the men and women of the time. This book examines the evidence for Old Norse sorcery, looking at its meaning and function, practice and practitioners, and the complicated constructions of gender and sexual identity with which these were underpinned. Combining strong elements of eroticism and aggression, sorcery appears as a fundamental domain of women's power, linking them with the gods, the dead and the future. Their battle spells and combat rituals complement the men's physical acts of fighting, in a supernatural empowerment of the Viking way of life. What emerges is a fundamentally new image of the world in which the Vikings understood themselves to move, in which magic and its implications permeated every aspect of a society permanently geared for war. In this fully revised and expanded second edition, Neil Price takes us with him on a tour through the sights and sounds of this undiscovered country, meeting its human and otherworldly inhabitants, including the Sámi with whom the Norse partly shared this mental landscape. On the way we explore Viking notions of the mind and soul, the fluidity of the boundaries that they drew between humans and animals, and the immense variety of their spiritual beliefs. We find magic in the Vikings' bedrooms and on their battlefields, and we meet the sorcerers themselves through their remarkable burials and the tools of their trade. Combining archaeology, history and literary scholarship with extensive studies of Germanic and circumpolar religion, this multi-award-winning book shows us the Vikings as we have never seen them before.
Poly(β-L-malic acid) (PMA) is a natural biopolyester that has pharmaceutical applications and other potential uses. In this study, we examined PMA production by 56 strains of the fungus Aureobasidium ...pullulans representing genetically diverse phylogenetic clades. Thirty-six strains were isolated from various locations in Iceland and Thailand. All strains from Iceland belonged to a newly recognized clade 13, while strains from Thailand were distributed among 8 other clades, including a novel clade 14. Thirty of these isolates, along with 26 previously described strains, were examined for PMA production in medium containing 5% glucose. Most strains produced at least 4 g PMA/L, and several strains in clades 9, 11, and 13 made 9–11 g PMA/L. Strains also produced both pullulan and heavy oil, but PMA isolated by differential precipitation in ethanol exhibited up to 72% purity with no more than 12% contamination by pullulan. The molecular weight of PMA from A. pullulans ranged from 5.1 to 7.9 kDa. Results indicate that certain genetic groups of A. pullulans are promising for the production of PMA.
Angustmycin A has anti-mycobacterial and cytokinin activities, and contains an intriguing structure in which an unusual sugar with C5'-C6' dehydration is linked to adenine via an N-glycosidic bond. ...However, the logic underlying the biosynthesis of this molecule has long remained obscure. Here, we address angustmycin A biosynthesis by the full deciphering of its pathway. We demonstrate that AgmD, C, A, E, and B function as D-allulose 6-phosphate 3-epimerase, D-allulose 6-phosphate pyrophosphokinase, adenine phosphoallulosyltransferase, phosphoribohydrolase, and phosphatase, respectively, and that these collaboratively catalyze the relay reactions to biosynthesize angustmycin C. Additionally, we provide evidence that AgmF is a noncanonical dehydratase for the final step to angustmycin A via a self-sufficient strategy for cofactor recycling. Finally, we have reconstituted the entire six-enzyme pathway in vitro and in E. coli leading to angustmycin A production. These results expand the enzymatic repertoire regarding natural product biosynthesis, and also open the way for rational and rapid discovery of other angustmycin related antibiotics.
T-2 toxin is a trichothecene mycotoxin produced when Fusarium fungi infect grains, especially oats and wheat. Ingestion of T-2 toxin contaminated grain can cause diarrhea, hemorrhaging, and feed ...refusal in livestock. Cereal crops infected with mycotoxin-producing fungi form toxin glycosides, sometimes called masked mycotoxins, which are a potential food safety concern because they are not detectable by standard approaches and may be converted back to the parent toxin during digestion or food processing. The work reported here addresses four aspects of T-2 toxin-glucosides: phytotoxicity, stability after ingestion, antibody detection, and the anomericity of the naturally occurring T-2 toxin-glucoside found in cereal plants. T-2 toxin-β-glucoside was chemically synthesized and compared to T-2 toxin-α-glucoside prepared with Blastobotrys muscicola cultures and the T-2 toxin-glucoside found in naturally contaminated oats and wheat. The anomeric forms were separated chromatographically and differ in both NMR and mass spectrometry. Both anomers were significantly degraded to T-2 toxin and HT-2 toxin under conditions that mimic human digestion, but with different kinetics and metabolic end products. The naturally occurring T-2 toxin-glucoside from plants was found to be identical to T-2 toxin-α-glucoside prepared with B. muscicola. An antibody test for the detection of T-2 toxin was not effective for the detection of T-2 toxin-α-glucoside. This anomer was produced in sufficient quantity to assess its animal toxicity.
Summary
Copper (Cu) concentration is greatly reduced in the open sea so that phytoplankton must adjust their uptake systems and acclimate to sustain growth. Acclimation to low Cu involves changes to ...the photosynthetic apparatus and specific biochemical reactions that use Cu, but little is known how Cu affects cellular metabolic networks. Here we report results of whole transcriptome analysis of a plastocyanin‐containing diatom, Thalassiosira oceanica 1005, during its initial stages of acclimation and after long‐term adaptation in Cu‐deficient seawater. Gene expression profiles, used to identify Cu‐regulated metabolic pathways, show downregulation of anabolic and energy‐yielding reactions in Cu‐limited cells. These include the light reactions of photosynthesis, carbon fixation, nitrogen assimilation and glycolysis. Reduction of these pathways is consistent with reduced growth requirements for C and N caused by slower rates of photosynthetic electron transport. Upregulation of oxidative stress defence systems persists in adapted cells, suggesting cellular damage by increased reactive oxygen species (ROS) occurs even after acclimation. Copper deficiency also alters fatty acid metabolism, possibly in response to an increase in lipid peroxidation and membrane damage driven by ROS. During the initial stages of Cu‐limitation the majority of differentially regulated genes are associated with photosynthetic metabolism, highlighting the chloroplast as the primary target of low Cu availability. The results provide insights into the mechanisms of acclimation and adaptation of T. oceanica to Cu deficiency.
Liamocins are structurally unique, heavier-than-water “oils” produced by certain strains of Aureobasidium pullulans. The aim of the current study is to identify new sources of liamocins and evaluate ...their potential as anticancer agents. Nine strains of A. pullulans from phylogenetic clades 8, 9, and 11 were examined for the first time for production of liamocins. Strains in these clades have only been isolated from tropical environments, and all strains tested here were from various locations in Thailand. Strains RSU 9, RSU 21, and RSU 29, all from clade 11, produced from 7.0 to 8.6 g liamocins/l from medium containing 5 % sucrose. These are the highest yields of liamocins that we have found thus far. These strains also produced from 9.4 to 17 g pullulan/l. The structural identity of liamocins was confirmed by matrix-assisted laser desorption/ionization mass spectrometry; differential spectra were obtained in which the dominant ion was either at about m/z 805.5 or m/z 949.6, consistent with the structure of liamocins. Liamocins from A. pullulans strains RSU 9 and RSU 21 inhibited two human breast cancer cell lines and a human cervical cancer cell line (IC₅₀ values of 32.2 ± 1.4 to 63.1 ± 2.4 μg liamocins/ml) but were not toxic to a normal cell line. Liamocins weakly inhibited a strain of Enterococcus faecalis, but did not inhibit strains of Lactobacillus fermentum, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Thus, A. pullulans phylogenetic clade 11 is a promising source of liamocins, and these compounds merit further examination as potential anticancer agents.
OBJECTIVES: To compare production of antibacterial liamocins (polyol lipids) by diverse strains of Aureobasidium pullulans grown on different culture media. RESULTS: Liamocins produced by strains of ...A. pullulans have potential agricultural and pharmaceutical applications as antibacterials with specificity against Streptococcus spp. Six strains of A. pullulans were characterized for liamocin production on four different culture media. The choice of strain and culture medium affected growth, liamocin yields, and production of contaminating pigments. Best growth and highest liamocin yields were obtained using A. pullulans strain NRRL 50384 grown on a sucrose basal medium. Unexpectedly, the choice of strain and culture medium also affected the structure of liamocins produced, providing novel types of liamocins. Liamocins varied not only in the ratios of trimer and tetramer polyester tail groups, but also in the nature of the polyol headgroup, which could include mannitol, arabitol, or glycerol. CONCLUSIONS: The ability to conveniently produce novel types of liamocins in good yields will provide novel antibacterials for applied uses, and facilitate structure-function studies on the mechanism of antibacterial activity.
•Soybeans obtained from many 2013-2016 production locations around the United States.•Analysis of total isoflavone and total saponin quantification performed by HPLC.•Preprocessing algorithms were ...applied to NIRS spectra to minimize variation.•Multiple Linear Regression based models predict isoflavone content.•Predictions had high regression coefficients, low standard errors of calibration.
Over 3200 discrete soybean samples were obtained from production locations around the United States during the years 2012–2016. Ground samples were scanned on near infrared spectrometers (NIRS) and analyzed by HPLC for total isoflavone and total saponin composition, as well as total carbohydrate composition. Multiple Linear Regression (MLR) analysis of preprocessed spectral data was used to develop optimized models to predict isoflavone content. The selection of a suitable calibration model was based on a high regression coefficient (R2), and lower standard error of calibration (SEC) values. Robust validated predictions were obtained for isoflavones, however less than robust calibrations were obtained for the total saponins. The correlations were not as robust for predicting the carbohydrate composition. NIRS is a suitable, rapid, nondestructive method to determine isoflavone composition in ground soybeans. Useful isoflavone composition predictions for large numbers of soybean samples can be obtained from quickly obtained NIRS scans.
Trichothecenes are sesquiterpenoid toxins produced by Fusarium species. Since these mycotoxins are very stable, there is interest in microbial transformations that can remove toxins from contaminated ...grain or cereal products. Twenty-three yeast species assigned to the Trichomonascus clade (Saccharomycotina, Ascomycota), including four Trichomonascus species and 19 anamorphic species presently classified in Blastobotrys, were tested for their ability to convert the trichothecene T-2 toxin to less-toxic products. These species gave three types of biotransformations: acetylation to 3-acetyl T-2 toxin, glycosylation to T-2 toxin 3-glucoside, and removal of the isovaleryl group to form neosolaniol. Some species gave more than one type of biotransformation. Three Blastobotrys species converted T-2 toxin into T-2 toxin 3-glucoside, a compound that has been identified as a masked mycotoxin in Fusarium-infected grain. This is the first report of a microbial whole-cell method for producing trichothecene glycosides, and the potential large-scale availability of T-2 toxin 3-glucoside will facilitate toxicity testing and development of methods for detection of this compound in agricultural and other products.
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