Preparation of Magnetic MIL-68(Ga) Metal-Organic Framework and Heavy Metal Ion Removal Application.

A magnetic metal-organic framework nanocomposite (magnetic MIL-68(Ga)) was synthesized through a "one pot" reaction and used for heavy metal ion removal. The morphology and elemental properties of the nanocomposite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), as well as zeta potential. Moreover, the factors affecting the adsorption capacity of the nanocomposite, including time, pH, metal ion type and concentration, were studied. It was found that the adsorption capacity of magnetic MIL-68(Ga) for Pb2+ and Cu2+ was 220 and 130 mg/g, respectively. Notably, the magnetic adsorbents could be separated easily using an external magnetic field, regenerated by ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) and reused three times, in favor of practical application. This study provides a reference for the rapid separation and purification of heavy metal ions from wastewater.

Function of the phosphatidylinositol synthase Pis1 in maintenance of endoplasmic reticulum function and pathogenicity in Candida albicans.

Candida albicans is a common conditional pathogenic fungus in the human body, and its infections have received widespread attention in recent years. Phosphatidylinositol and its derivatives have significant regulatory effects on many physiological processes, such as cell metabolism and growth. In this study, we identified and studied the function of the phosphatidylinositol synthase Pis1 in Candida albicans. The protein has a conserved CAPT motif and multiple transmembrane domains. GFP tagging revealed that Pis1 was located at the endoplasmic reticulum (ER). The PIS1 knockout mutant was constructed using an induction system regulated by the MET3 promoter. Growth assays showed that PIS1 is an essential gene for normal growth of Candida albicans. Overexpression of PIS1 led to high sensitivity to both ER stress and cell wall stress, and down-regulated expression of the genes involved in ER stress response and maintenance of cell wall integrity. Interestingly, PIS1 overexpression enhanced secretion of the extracellular hydrolases. Virulence assays further revealed that PIS1 overexpression increased the fungal virulence, leading to quicker death of the fungus-infected mice and more severe fungal burden in the mouse kidneys. In summary, Pis1 is involved in ER stress response, maintenance of cell wall integrity, and pathogenicity of Candida albicans.

The Vacuole and Mitochondria Patch (vCLAMP) Protein Vam6 is Crucial for Autophagy in Candida albicans.

Vacuole and mitochondria patches (vCLAMPs) are involved in the stress resistance of yeast, but their exact role in autophagy remains so far unclear. This study, for the first time, investigated the role of the vCLAMP core protein Vam6 in autophagy of Candida albicans. The experiments demonstrated that the deletion of VAM6 led to a growth defect under nitrogen starvation. Also, western blotting revealed that the vam6Δ/Δ mutant attenuated degradation of Atg8 (an autophagy indicator), Lap41 (an indicator of the cytoplasm to vacuole targeting pathway), and Csp37 (a mitophagy indicator). Moreover, the activity of carboxypeptidase Y and the levels of the vacuolar phospholipase Atg15 were significantly decreased in the mutant, which confirmed the defect of autophagy caused by deletion of VAM6. Overall, these results revealed that Vam6 is essential in maintaining the autophagic process under nitrogen starvation, and this provided new insights into the correlation between vCLAMPs and autophagy.

The Vacuole and Mitochondria Patch (vCLAMP) Protein Mcp1 Is Involved in Maintenance of Mitochondrial Function and Mitophagy in Candida albicans.

The vacuole and mitochondria patches (vCLAMPs) are novel membrane contact sites in yeast. However, their role in autophagy has not been elucidated so far. In this article, the role of Mcp1, one core component of vCLAMP, in mitophagy of Candida albicans was investigated. Deletion of MCP1 led to abnormal accumulation of enlarged mitochondria and attenuated stability of mitochondrial DNA (mtDNA) in C. albicans when cultured in non-fermentable carbon sources. Furthermore, the mcp1Δ/Δ mutant exhibited defective growth and degradation of Csp37-GFP. These results indicate that Mcp1 plays a crucial role in mitophagy and maintenance of mitochondrial functions under the non-fermentable condition. Interestingly, this deletion had no impact on degradation of Atg8 (the macroautophagy reporter) and Lap41 (the cytoplasm-to-vacuole targeting pathway marker) under SD-N medium. Moreover, deletion of MCP1 inhibited filamentous growth and impaired virulence of the pathogen. This study provides an insight to vCLAMPs in cellular functions and pathogenicity in C. albicans.