A microworld in Triassic amber

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Testate Amoeba Communities of Epilithic Mosses and Lichens: New Data from Russia, Switzerland and Italy

The testate amoebae (TA) of many potential habitats around the world have been barely investigated but data on species presence and abundance is essential to answering big questions about microbial biogeography and the diversity of protist life. One such habitat lacking basic data is epilithic mosses and lichens with only a small number of samples analysed in previous studies and no systematic attempt to understand potential environmental controls. We use a large dataset (n = 81) from sites in Russia, Switzerland and Italy to demonstrate that testate amoebae in this habitat are both abundant and diverse. The community of our samples was dominated by ubiquitous taxa and differed between the northern (Russia) and southern (Switzerland and Italy) sites, perhaps due to differences in climate or air quality. Community composition, concentration and diversity were explained by moisture content but not by elevation above the ground surface and there were no significant differences between communities of mosses and lichens. Surprisingly our data showed a significant difference between communities of epiphytic and epilithic lichens in the same region sampled at the same time. Our study adds to the evidence that moisture availability is a critical factor in structuring testate amoeba communities across habitats and highlights the paucity of knowledge of TA in many environments

Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma

Photodynamic therapy (PDT) is a treatment of cancer whereby tumours are destroyed by reactive oxygen species generated upon photoactivation of a photosensitizer drug. Hydrophobic photosensitizers are known to be ideal for PDT; however, their hydrophobicity necessitates that they are typically administered using emulsions. Here, a delivery vehicle for photodynamic therapy based on the co-self-assembly of both a Zn(ii)-phthalocyanine derivative photosensitizer and a polyethylene glycol (PEG) derivative onto gold nanoparticles is reported. The PEG on the particle surface ensured that the conjugates were water soluble and enhanced their retention in the serum, improving the efficiency of PDT in vivo. The pharmacokinetic behaviour of the nanoparticle conjugates following intravenous injection into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma showed a significant increase of retention of the nanoparticles in the tumour. PDT tumour destruction was achieved 3 h following injection of the nanoparticle conjugates leading to a remarkable 40% of the treated mice showing no tumour regrowth and complete survival. These results highlight that dual functionalised nanoparticles exhibit significant potential in PDT of cancer especially for difficult to treat cancers such as amelanotic melanoma

Novel, Meso-Substituted Cationic Porphyrin Molecule for Photo-Mediated Larval Control of the Dengue Vector Aedes aegypti

Dengue is a life-threatening viral disease of growing importance, transmitted by Aedes mosquito vectors. The control of mosquito larvae is crucial to contain or prevent disease outbreaks, and the discovery of new larvicides able to increase the efficacy and the flexibility of the vector control approach is highly desirable. Porphyrins are a class of molecules which generate reactive oxygen species if excited by visible light, thus inducing oxidative cell damage and cell death. In this study we aimed at assessing the potential of this photo-mediated cytotoxic mechanism to kill Aedes (Stegomyia) aegypti mosquito larvae. The selected porphyrin molecule, meso-tri(N-methylpyridyl),meso-mono(N-tetradecylpyridyl)porphine (C14 for simplicity), killed the larvae at doses lower than 1 µM, and at light intensities 50–100 times lower than those typical of natural sunlight, by damaging their intestinal tissues. The physicochemical properties of C14 make it easily adsorbed into organic material, and we exploited this feature to prepare an ‘insecticidal food’ which efficiently killed the larvae and remained active for at least 14 days after its dispersion in water. This study demonstrated that photo-sensitizing agents are promising tools for the development of new larvicides against mosquito vectors of dengue and other human and animal diseases