Biooxidation of hydrogen sulfide to sulfur by moderate thermophilic acidophilic bacteria.

The copper industry utilizes significant amounts of sulfuric acid in its processes, generating sulfate as waste. While sulfate-reducing bacteria can remove sulfate, it produces hydrogen sulfide (H2S) as a byproduct. This study examined the capability of a consortium consisting of Sulfobacillus thermosulfidooxidans and Sulfobacillus acidophilus to partially oxidize H2S to S° at a temperature of 45 °C. A fixed-bed bioreactor, with glass rings as support material and sodium thiosulfate as a model electron donor, was inoculated with the consortium. Formation of biofilms was crucial to maintain the bioreactor's steady state, despite high flow rates. Afterward, the electron donor was changed to H2S. When the bioreactor was operated continuously and with high aeration, H2S was fully oxidized to SO42-. However, under conditions of low aeration and at a concentration of 0.26 g/L of H2S, the consortium was able to oxidize H2S to S° with a 13% yield. S° was discovered attached to the glass rings and jarosite. The results indicate that the consortium could oxidize H2S to S° with a 13% yield under low aeration and at a concentration of 0.26 g/L of H2S. The findings highlight the capability of a Sulfobacillus consortium to convert H2S into S°, providing a potential solution for addressing environmental and safety issues associated with sulfate waste generated by the mining industry.

Endocarditis caused by anaerobic bacteria.

BACKGROUND: Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). METHODS: We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). RESULTS: Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). CONCLUSION: IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms.

Heavy ion beam measurement of the hydration of cementitious materials.

The setting and development of strength of Portland cement concrete depends upon the reaction of water with various phases in the Portland cement. Nuclear resonance reaction analysis (NRRA) involving the (1)H((15)N,alpha,gamma)(12)C reaction has been applied to measure the hydrogen depth profile in the few 100 nm thick surface layer that controls the early stage of the reaction. Specific topics that have been investigated include the reactivity of individual cementitious phases and the effects of accelerators and retarders.

Cholinesterase inhibitor rivastigmine enhance the mitochondrial electron transport chain in lymphocytes of patients with Alzheimer's disease.

Electron transport chain (ETC) dysfunction has been claimed to contribute to the expression of neurodegenerative disorders. We have investigated the effects of the treatment with rivastigmine, a commonly used cholinesterase inhibitor, on lymphocyte mitochondria of patients with Alzheimer's disease (AD). Increased enzymatic activities of diverse complexes and oxidative capacity of the ETC were found. Enhanced mitochondrial ETC function may contribute to the beneficial effects of rivastigmine on clinical manifestations of AD.

[Cardiac tamponade as a clinical symptom of systemic lupus erythematosus]. / Taponamiento cardíaco como presentación clínica de lupus eritematoso sistémico.

Pericarditis is the most frequent cardiac manifestation of systemic lupus erythematosus (SLE), but pericardial effusion causing tamponade rarely occurs, and it is even less frequent for the pericardial tamponade to be the presenting feature of SLE. We report a case of pericardial tamponade due to SLE with severe hemodynamic involvement as the clinical presentation of the disease. We comment on its clinical course and its rarity in the medical literature.

[Biomass of Rhizopus oligosporus as an adsorbent for metal ions]. / Biomasa de Rhizopus oligosporus como adsorbente de iones metálicos.

The effect of different parameters on the adsorption of metal ions by Rhizopus oligosporus has been studied. The uranium sorption by dried biomass was rapid, reaching in 5 min around 95.% of the binding capacity. The uranium-binding capacity of the culture showed an inverse relation to the growth kinetic. The relationship between sorption and equilibrium concentration was similar to an adsorption isotherm. Using the Langmuir model, a maximum sorption capacity of 0.52 mmoles uranium/g dry biomass and an affinity constant of 101 l/mmol uranium at pH 4.15 were determined. The best capacity of the biomass to bind ions (UO2(2+), Cu2+, Cd2+ and Zn2+) was best at pH 4.5-5.5. By using hydrochloric acid as eluant a 18% uranium removal of the biomass-bound ions was obtained at pH 1.0. The presence of other cations inhibited uranium-binding in the following order: Cu2+ > Cd2+ > Zn2+ > Mg2+ > Ca2+.

[Pulmonary infection caused by Rhodococcus equi in a renal transplant recipient]. / Infección pulmonar por Rhodococcus equi en un trasplantado renal.

Rhodococcus equi is a primarily pathogen in animals and it has only rarely been seen in immunocompromised humans. We describe our experience with an HIV-negative patient with a functioning renal graft under cyclosporin-azathioprine-prednisone therapy. The patient died after a two months recurrent multifocal pneumonia. The cultures from sputum and blood were negatives but R. equi was isolated from lungs in the necropsy. Most of the 41 cases we had found in the literature had AIDS or HIV infection. Six cases had a kidney graft under azathioprine-prednisone therapy. Rhodococcus equi infection may be missed in some instances due to incomplete or improper identification of the organism, that grows well in aerobic media but is usually regarded as a component of normal flora or as a contaminant. The ability of R. equi to persist in and eventually to destroy macrophages is the basis of its pathogenicity. It also explains the clinical resistance to antibiotics without intracellular activity. Rhodococcus equi infection must be suspected in immunocompromised patients with recurrent pneumonia. Correct identification and combined therapy with lipophilic antibiotics that penetrate the macrophages are necessary to prevent the high mortality of this infection.

Biosorption of metal ions byAzotobacter vinelandii.

Azotobacter vinelandii was better than eitherDerxia gummosa orRhizobium trifolii for sorption of UO 2 (2+) . Its maximum binding capacity was 0.25 mmol UO 2 (2+) /g dry biomass with an affinity constant of 333 l/mmol at pH 4.1 according to the Langmuir model. In a semisynthetic medium,A. vinelandii showed the highest sorption capacity in the early stationary phase. The binding of UO 2 (2+) , Cu(2+), Ca(2+) and Zn(2+) was affected by the pH of the solution. With HCl as eluent, virtually all the sorbed UO 2 (2+) was released. The presence of Cu(2+), Cd(2+), Ca(2+), and Zn(2+) inhibited the UO 2 (2+) biosorption whereas Mg(2+) and K(+) had no effect.