The Geological Roles Played by Microfungi in Interaction with Sulfide Minerals from Libiola Mine,Liguria, Italy

The potential role played by fungi in the weathering of sulfide abandoned mines and waste rock dumps is scarcely investigated, yet. In particular microfungi may produce biofilms that work as sites of metals and minerals precipitation. This study aimed to investigate interactions, bioalteration, and biocorrosion between three microfungi (Trichoderma harzianum group, Penicillium glandicola, P. brevicompactum) isolated from the Libiola sulfide mine (Liguria, Italy) and pyrite-rich mineralizations occurring within the waste rock dumps. After six weeks of incubation, Environmental Scanning Electron Microscope (ESEM) analyses showed how single pyrite crystals were completely corroded and altered by all the selected species. These results represent the first step to establish that fungi play a central role in the biogeochemical cycles of extreme and contaminated sites such as sulfide mines, and that they actively contribute to the evolution of the degraded ecosystem to more harmonized scenery.     

Gypsum Biomineralization in Sulphide-rich Hardpans by a Native Trichoderma harzianum Rifai Strain

Natural acid mine drainage affects abandoned sulfide mines worldwide, causing hardpan formation and heavy metal leaching. Hardpans are characterized by very low permeability, thus representing a significant limiting factor for oxygen and water circulation in the rhizosphere. Our work shows the results concerning the gypsum biomineralization capability of a native Trichoderma harzianum Rifai strain in sulfide -rich hardpans. Two months after the fungal inoculum, hardpan clasts resulted, completely covered by T. harzianum mycelium, where newly formed gypsum crystals occur. Our study provided the first evidence about interaction between T. harzianum and sulfide -mineralized hardpans as well as about its influence on gypsum genesis.     

Diel modulation of Hsp70 and Hsp60 in corals living in a shallow reef

Coral Reefs - In corals, different biological processes are associated with the daily variation of temperature and light, which in shallow reefs can vary widely and regularly reach extreme levels....     

Cytokine-Regulated Expression of Platelet-Derived Growth Factor Gene and Protein in Cultured Human Astrocytes

Abstract: To elucidate mechanisms regulating the production of platelet-derived growth factor (PDGF) in the CNS, we analyzed the influence of a panel of cytokines on PDGF mRNA and protein levels in astrocyte-enriched cultures from the human embryonic brain and spinal cord. Using a specific ELISA, PDGF AB protein was detected in serum-free astrocyte supernatants and its levels were significantly increased after treatment of the cultures with transforming growth factor-β₁ (TGF-β₁) or tumor necrosis factor-α (TNF-α); the largest increase was detected after combined treatment with the two cytokines. Interleukin-1β (IL-1β) by itself had little or no effect but synergized with TGF-β₁ in enhancing PDGF AB production. Supernatants from human astrocyte cultures stimulated the proliferation of rat oligodendrocyte progenitors, and most of the mitogenic activity could be accounted for by PDGF. By northern blot analysis, both PDGF A- and PDGF B-chain mRNAs were detected in untreated astrocytes. PDGF B-chain mRNA levels were increased by TGF-β₁, TNF-α, TNF-α/TGF-β₁, or IL-1β/TGF-β₁, whereas PDGF A-chain mRNA levels were not consistently affected by cytokine treatments. These in vitro data indicate that TGF-β₁, TNF-α, and IL-1β are able to stimulate astrocyte PDGF production. This cytokine network could play a role in CNS development and repair after injury or inflammation.     

Specific compositional patterns of synonymous positions in homologous mammalian genes

All 69 homologous coding sequences that are currently available in four mammalian orders were aligned and the synonymous (ie., third) positions of quartet (fourfold degenerate) codons were divided into three classes (that will be called conserved, intermediate, and variable), according to whether they show no change, one change, and more than one change, respectively. The three classes were analyzed in their compositional patterns. In the majority of GC-rich genes, the three classes of positions (but especially conserved positions) exhibited significantly different base compositions compared to expectations based on a random substitution process from the ancestral (consensus) sequence to the present-day (actual) sequences. Significant differences were rare in GC-poor genes.An analysis of the present results indicates that natural selection plays a role in the synonymous nucleotide substitution process, especially in GC-rich genes which represent the vast majority of mammalian genes.This paper is dedicated to the memory of Dr. Motoo Kimura (1924–1994)Correspondence to: Giorgio Bernardi