Biologically Active Metabolites Produced by the Basidiomycete Quambalaria cyanescens

Four strains of the fungus Quambalaria cyanescens (Basidiomycota: Microstromatales), were used for the determination of secondary metabolites production and their antimicrobial and biological activities. A new naphthoquinone named quambalarine A, (S)-(+)-3-(5-ethyl-tetrahydrofuran-2-yliden)-5,7,8-trihydroxy-2-oxo-1,4-naphthoquinone (1), together with two known naphthoquinones, 3-hexanoyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone (named here as quambalarine B, 2) and mompain, 2,5,7,8-tetrahydroxy-1,4-naphthoquinone (3) were isolated. Their structures were determined by single-crystal X-ray diffraction crystallography, NMR and MS spectrometry. Quambalarine A (1) had a broad antifungal and antibacterial activity and is able inhibit growth of human pathogenic fungus Aspergillus fumigatus and fungi co-occurring with Q. cyanescens in bark beetle galleries including insect pathogenic species Beauveria bassiana. Quambalarine B (2) was active against several fungi and mompain mainly against bacteria. The biological activity against human-derived cell lines was selective towards mitochondria (2 and 3); after long-term incubation with 2, mitochondria were undetectable using a mitochondrial probe. A similar effect on mitochondria was observed also for environmental competitors of Q. cyanescens from the genus Geosmithia.     

An Application of the Shark Skin Denticle Geometry for Windbreak Fence Design and Fabrication

Windbreak fences in open and urban areas can be used to effectively reduce the wind velocity.In this paper we examine how the geometrical shape of the windbreak fence can optimally mitigate wind velocity.We propose an approach for windbreak fence design based on a bionic parametric model of the shark skin denticle geometry,which improves the reduction of the wind velocity around and behind the windbreak fences.The generative model was used to estimate improvements by variations in the parameters of the fence panel's geometrical shape,inspired by shark skin denticles.The results of the Computational Fluid Dynamics (CFD) analysis indicates that the fence surface inspired by shark skin performs much better than both flat and corrugated surfaces.Taking into account the complex geometry of the surface inspired by shark skin denticles,we propose a fabrication process using an expanded polystyrene foam (EPS) material,created using an industrial robot ann with a hot-wire tool.Creating EPS moulds for the shark skin denticle panels allows for a richer variety material to be used in the final design,leading both to higher efficiency and a more attractive design.     

Anti‐angiogenic effects of the blue‐green alga Arthrospira platensis on pancreatic cancer

Arthrospira platensis, a blue‐green alga, is a popular nutraceutical substance having potent antioxidant properties with potential anti‐carcinogenic activities. The aim of our study was to assess the possible anti‐angiogenic effects of A platensis in an experimental model of pancreatic cancer. The effects of an A platensis extract were investigated on human pancreatic cancer cells (PA‐TU‐8902) and immortalized endothelial‐like cells (Ea.hy926). PA‐TU‐8902 pancreatic tumours xenografted to athymic mice were also examined. In vitro migration and invasiveness assays were performed on the tested cells. Multiple angiogenic factors and signalling pathways were analysed in the epithelial, endothelial and cancer cells, and tumour tissue. The A platensis extract exerted inhibitory effects on both migration and invasion of pancreatic cancer as well as endothelial‐like cells. Tumours of mice treated with A platensis exhibited much lesser degrees of vascularization as measured by CD31 immunostaining (P = .004). Surprisingly, the VEGF‐A mRNA and protein expressions were up‐regulated in pancreatic cancer cells. A platensis inhibited ERK activation upstream of Raf and suppressed the expression of ERK‐regulated proteins. Treatment of pancreatic cancer with A platensis was associated with suppressive effects on migration and invasiveness with various anti‐angiogenic features, which might account for the anticancer effects of this blue‐green alga.     

The form of a trade‐off determines the response to competition

Understanding how populations and communities respond to competition is a central concern of ecology. A seminal theoretical solution first formalised by Levins (and re‐derived in multiple fields) showed that, in theory, the form of a trade‐off should determine the outcome of competition. While this has become a central postulate in ecology it has evaded experimental verification, not least because of substantial technical obstacles. We here solve the experimental problems by employing synthetic ecology. We engineer strains of Escherichia coli with fixed resource allocations enabling accurate measurement of trade‐off shapes between bacterial survival and multiplication in multiple environments. A mathematical chemostat model predicts different, and experimentally verified, trajectories of gene frequency changes as a function of condition‐specific trade‐offs. The results support Levins' postulate and demonstrates that otherwise paradoxical alternative outcomes witnessed in subtly different conditions are predictable.     

The Effects of Mycoplasma Contamination upon the Ability to Form Bioengineered 3D Kidney Cysts

Mycoplasma contamination of cell cultures is a pervasive, often undiagnosed and ignored problem in many laboratories that can result in reduced cell proliferation and changes in gene expression. Unless contamination is specifically suspected, it is often undetected in two dimensional (2D) cultures and the resulting effects of mycoplasma contamination are rarely appreciated and can lead to incorrect conclusions. Three dimensional (3D) tissue cultures are increasingly utilized to explore tissue development and phenotype. However, 3D cultures are more complex than 2D cell cultures and require a more controlled cellular environment in order to generate structures necessary to mimic in vivo responses and are often maintained for longer time periods. Changes to the microenvironment are assumed to have a more extreme effect upon the success of 3D tissue cultures than 2D cell cultures, but the effects of mycoplasma have not been studied. To test this hypothesis, we grew 2D cell cultures and 3D tissues from pig kidney epithelial cells (LLC-PK1) that were contaminated with mycoplasma and the same stock of cells after mycoplasma removal. We did not observe an effect of mycoplasma contamination on proliferation in 2D monolayer cell culture. However, cyst formation in 3D tissues was altered, with effects upon the number, size and structure of cysts formed. These data serve to reinforce the necessity of testing cell stocks for mycoplasma contamination.     

Midkine and Pleiotrophin Concentrations in Amniotic Fluid in Healthy and Complicated Pregnancies

BackgroundMidkine (MDK) and pleiotrophin (PTN) are heparin-binding growth factors that, in rodents, are highly expressed in early life and decrease to undetectable levels by adulthood. The potential roles of MDK and PTN in human growth and development are not completely elucidated.ConclusionThe concentration of MDK but not that of PTN declined with gestational age. Both MDK and PTN concentrations were found to be lower in pregnancies that were complicated by chorioamnionitis at term, raising the possibility that these growth factors might be useful as markers for infection.