The Machanism of Bacterial Oxidation of Sulphides

The bacteria used in the experiment are Thiobacillus Ferrooxidans separated from acidic mine water in sulphide deposits. The chemoautotrophic bacteria can act directly on sulphides and accelerate the oxidation of sulphides. The experiment shows that the bacteria, as an important microbial factor of gold's supergenous enrichment within the oxidized zones of sulphide deposits, are helpful to dissolve gold and silver in ferric sulphate. In the bacterial oxidation process, the precipitation of goethite is concerned both with the lower activity of ferric ions and with the existence of carbonates in solution. Meanwhile, the acid-resisting and oxidizing ability of the bacteria will certainly lead up to a microbial way of treating the acidic mine water.

Implantable versatile oxidized bacterial cellulose membrane for postoperative HNSCC treatment via photothermal-boosted immunotherapy

The recurrence of head and neck squamous cell carcinoma(HNSCC)after surgical resection continues to pose a major challenge to cancer treatment.Advanced HNSCC exhibits a low response rate to immune checkpoint blockade(ICB),while photothermal therapy(PTT)can increase the infiltration of immune cells to make tumors more susceptible to cancer immunotherapy.In this regard,we designed and constructed a novel multifunctional nanocomposite comprised of oxidized bacterial cellulose(OBC),thrombin(TB),and gold nanocages(AuNCs)containing anti-programmed death 1(PD-1)antibody(αPD-1@AuNCs),which allows the combination of therapies with remarkable postoperative antitumor immunity to control local tumor recurrence.TheαPD-1@AuNCs displayed high light-to-heat conversion efficiency and induced pyroptosis under near infrared(NIR)irradiation,which activated a potent antitumor immune response.More importantly,the therapeutic system could induce tumor pyroptosis and enhance antitumor immune response by increasing T-cell infiltration and reducing the immune suppressive cells,when combined with local ICB therapy,which effectively avoided the tumor recurrence in a HNSCC postoperative mice model.Overall,the newly developed multifunctional nanocomposites could be a promising candidate for the treatment of postoperative HNSCC.

Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive （Staphylococcus aureus） and gram-negative （Escherichia coli, Pseudomonas aeruginosa） bacteria. Particle size, morphology and chemical composition were determined using scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. Results indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus, but not against Escherichia coli and Pseudomonas aeruginosa. It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacterial cell wall. Furthermore, lanthanum oxide bulk particles were fotmd to enhance the pyocyanin pigment production in Pseudomonas aeruginosa.