Understanding a Core Pilin of the Type IVa Pili of Acidithiobacillus thiooxidans, PilV

( Araceli Hernández-sánchez ),( Edgar D. Páez-pérez ),( Elvia Alfaro-saldaña ),( Vanesa Olivares-illana ),( J. Viridiana García-meza ) 한국미생물생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.3

Pilins are protein subunits of pili. The pilins of type IV pili (T4P) in pathogenic bacteria are well characterized, but anything is known about the T4P proteins in acidophilic chemolithoautotrophic microorganisms such as the genus Acidithiobacillus. The interest in T4P of A. thiooxidans is because of their possible role in cell recruitment and bacterial aggregation on the surface of minerals during biooxidation of sulfide minerals. In this study we present a successful ad hoc methodology for the heterologous expression and purification of extracellular proteins such as the minor pilin PilV of the T4P of A. thiooxidans, a pilin exposed to extreme conditions of acidity and high oxidation-reduction potentials, and that interact with metal sulfides in an environment rich in dissolved minerals. Once obtained, the model structure of A. thiooxidans PilV revealed the core basic architecture of T4P pilins. Because of the acidophilic condition, we carried out in silico characterization of the protonation status of acidic and basic residues of PilV in order to calculate the ionization state at specific pH values and evaluated their pH stability. Further biophysical characterization was done using UV-visible and fluorescence spectroscopy and the results showed that PilV remains soluble and stable even after exposure to significant changes of pH. PilV has a unique amino acid composition that exhibits acid stability, with significant biotechnology implications such as biooxidation of sulfide minerals. The biophysics profiles of PilV open new paradigms about resilient proteins and stimulate the study of other pilins from extremophiles.

A Key Metabolic Regulator of Bone and Cartilage Health

Elizabeth Pérez-Hernández,Jesús Javier Pastrana-Carballo,Fernando Gómez-Chávez,Ramesh C. Gupta,Nury Pérez-Hernández 대한내분비학회 2022 Endocrinology and metabolism Vol.37 No.4

Taurine, a cysteine-derived zwitterionic sulfonic acid, is a common ingredient in energy drinks and is naturally found in fish and other seafood. In humans, taurine is produced mainly in the liver, and it can also be obtained from food. In target tissues, such as the retina, heart, and skeletal muscle, it functions as an essential antioxidant, osmolyte, and antiapoptotic agent. Taurine is also involved in energy metabolism and calcium homeostasis. Taurine plays a considerable role in bone growth and development, and high-profile reports have demonstrated the importance of its metabolism for bone health. However, these reports have not been collated for more than 10 years. Therefore, this review focuses on taurine–bone interactions and covers recently discovered aspects of taurine’s effects on osteoblastogenesis, osteoclastogenesis, bone structure, and bone pathologies (e.g., osteoporosis and fracture healing), with due attention to the taurine–cartilage relationship.

CCWater − A computer program for chemical classification of geothermal waters

Rodolfo Pérez-Espinosa,Kailasa Pandarinath,Francisco Javier Hernández-Campos 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.4

CCWater is a computer program developed for the application of extensively being used triangular diagrams for chemical classification and for identification of equilibrium conditions of waters. The program for these diagrams were developed as a Microsoft ExcelTM spreadsheet application and compiled using Visual BasicTM 6.0, which has enabled to execute an ExcelTM file from a program created by Visual BasicTM 6.0. The performances of all the four diagrams were validated by applying for the same chemical concentration data of the waters that was used by the original authors of these diagrams. The results obtained from this program were consistent with those of the original authors of these diagrams. As an example, CCWater is applied for chemical characterization of thermal waters from springs and geothermal wells of five geothermal fields of Mexico, in which four are electricity producing fields (Cerro Prieto, CPGF; Las Tres Vírgenes, LTVGF; Los Azufres, LAGF, and Los Humeros, LHGF) and the fifth geothermal field (La Primavera, LPGF) is in exploration stage. Majority of the reservoir temperatures estimated by Na/K geothermometers from geothermal well waters of CPGF, LAGF, LTVGF, and LPGF are within the limits of accepted differences (within ±20%) comparing to the average BHTs of the respective geothermal well. The good performances of the geothermometers in predicting the reservoir temperatures from well waters is expected because the well waters are fully equilibrated and are of Cl type, thus fulfilling the basic requirements. In contrary, though the spring waters of LHGF and LAGF are of HCO3 type (immature) and exhibited no equilibrium conditions, they also predicted reliable reservoir temperatures. This unusual but important observation in the behavior of the spring waters of LHGF and LAGF was made possible to known by chemical classification of these waters in to different groups and estimation of the reservoir temperatures by considering each water type of a geothermal field as a separate group. This application has shown the importance of chemical type of water and the existing chemical equilibrium conditions in successful using these waters in estimation of the reservoir temperatures, and hence the necessity of the computer program like CCWater. The software CCWater is easy to use, reliable, freely available and will be useful in the application of ternary diagrams for chemical characterization and to evaluate the equilibrium conditions of geothermal waters, particularly during the initial stage of geothermal exploration.

A Bordetella pertussis proteoliposome induces protection in mice without affecting the immunogenicity of diphtheria and tetanus toxoids in a trivalent formulation

Sonsire Fernández Castillo,Mario Landys Chovel,Niurka Gutiérrez Hernández,Lorena Corcho González,Amaya Blanco,Daily Serrano Hernández,Mildrey Fariñas Medina,Maydelis Álvarez Tito,José Luis Pérez Quiño 대한백신학회 2016 Clinical and Experimental Vaccine Research Vol.5 No.2

In this study, a formulation of Bordetella pertussis proteoliposome (PLBp), diphtheria, and tetanus toxoids and alum (DT-PLBp) was evaluated as a trivalent vaccine candidate in BALB/c mice. Vaccine-induced protection was estimated using the intranasal challenge for pertussis and enzyme-linked immunosorbent assay to assess serological responses for diphtheria or tetanus. Both, diphtheria-tetanus-whole cell pertussis (DTP) and diphtheria-tetanus vaccines (DT) were used as controls. Animals immunized with DT-PLBp, PLBp alone, and DTP showed total reduction of CFU in lungs 7 days after intranasal challenge. Likewise, formulations DT-PLBp, DTP, and DT elicited antibody levels ≥2 IU/mL against tetanus and diphtheria, considered protective when neutralization tests are used. Overall, results showed that combination of PLBp with tetanus and diphtheria toxoids did not affect the immunogenicity of each antigen alone.

Hyperbaric oxygenation applied before or after mild or hard stress: effects on the redox state in the muscle tissue

Claudia Carolina Pérez-Castro,Alexandre Kormanovski,Gustavo Guevara-Balcázar,María del Carmen Castillo-Hernández,José Rubén García-Sánchez,Ivonne María Olivares-Corichi,Pedro López-Sánchez,Iván Rubio- 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.1

The mechanism is unclear for the reported protective effect of hyperbaric oxygen preconditioning against oxidative stress in tissues, and the distinct effects of hyperbaric oxygen applied after stress. The trained mice were divided into three groups: the control, hyperbaric oxygenation preconditioning, and hyperbaric oxygenation applied after mild (fasting) or hard (prolonged exercise) stress. After preconditioning, we observed a decrease in basal levels of nitric oxide, tetrahydrobiopterin, and catalase despite the drastic increase in inducible and endothelial nitric oxide synthases. Moreover, the basal levels of glutathione, related enzymes, and nitrosative stress only increased in the preconditioning group. The control and preconditioning groups showed a similar mild stress response of the endothelial and neuronal nitric oxide synthases. At the same time, the activity of all nitric oxide synthase, glutathione (GSH) in muscle, declined in the experimental groups but increased in control during hard stress. The results suggested that hyperbaric oxygen preconditioning provoked uncoupling of nitric oxide synthases and the elevated levels of GSH in muscle during this study, while hyperbaric oxygen applied after stress showed a lower level of GSH but higher recovery post-exercise levels in the majority of antioxidant enzymes. We discuss the possible mechanisms of the redox response and the role of the nitric oxide in this process

Hydrodynamic effects on the overall adsorption rate of phenol on activated carbon cloth through the advection-diffusion model application

E. García-Hernández,C.G. Aguilar-Madera,E.C. Herrera-Hernández,R. Ocampo-Pérez,E. Bailón-García,Farid B. Cortés 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-

In this work, a mathematical formulation based on fundamental principles of momentum and masstransport with a kinetic adsorption model at the liquid-solid interface is proposed. This formulation wasnumerically solved and used for the interpretation of adsorption rate data of phenol onto an activatedcarbon cloth in a stirred tank adsorber under different agitation rates. The mathematical model solutionwas compared with the obtained by mathematical models that neglect the local velocity andconcentration profiles in the solution; external mass transfer model (EMTM) and thefirst-order kineticmodel (FOM). The results showed that under all studied stirring speeds (30 200 rpm) the proposedmodel was able to capture the dynamics of the concentration decay curves, while EMTM and FOM modelswere only able to interpret the data at high stirring speeds, indicating that velocity profiles play animportant role during phenol adsorption. Particular “wake zones” were identified behind the mobileadsorbent, which importantly promotes the transport of solute toward the activated carbon cloth. As aresult, it was found that convective transport is much more important than diffusive transport in thesolution.

One‑ and two‑dimensional carbon nanomaterials as adsorbents of cationic and anionic dyes from aqueous solutions

E. E. Pérez‑Ramírez,M. de la Luz‑Asunción,A. L. Martínez‑Hernández,G. de la Rosa‑Álvarez,S. Fernández‑Tavizón,P. Salas,C. Velasco‑Santos 한국탄소학회 2019 Carbon Letters Vol.29 No.2

One- and two-dimensional carbon nanomaterials were tested as adsorbents for the elimination of two anionic dyes, reactive red 2 and methyl orange, and the cationic dye methylene blue from aqueous solutions under the same conditions. Carbon nanomaterials performed well in the removal of dyes. Surface oxygenated groups in the nanomaterials improved the cationic dyes’ adsorption, but not the adsorption of the anionic dye. The interactions between nanomaterials and dyes were verified by infrared and Raman spectroscopy. The pseudo-second order kinetic model was better fitted to the kinetic experimental data than the Elovich and pseudo-first order models. The equilibrium adsorption data were best fitted by the Langmuir model. The dimensions and morphology of the carbon nanomaterials play an important role in the adsorption of the three dyes. The main mechanism of adsorption of anionic dyes is by the interactions of the aromatic rings of the dye structures and π delocalized electrons on carbon nanostructures; the adsorption of cationic dye is mainly due to electrostatic interactions.

Sorption of BTEX on a nanoporous composite of SBA-15 and a calcined hydrotalcite

Sampieri Alvaro,Pérez-Osorio Gabriela,Hernández-Espinosa Miguel Ángel,Ruiz-López Irving Israel,Ruiz-Reyes Mayra,Arriola-Morales Janette,Narváez-Fernández Rocío Iliana 나노기술연구협의회 2018 Nano Convergence Vol.5 No.21

Benzene, toluene, ethylbenzene, and p-xylene (BTEX) are hazardous volatile organic compounds mostly released from fuel combustion, paint gas emissions, and biomass burning. In this work, it is studied the BTEX sorption influence on the surface reactivity of a new kind of nanoporous composite, prepared via an in situ functionalization of SBA-15 with a Mg–Al calcined hydrotalcite (HTC). During its preparation, Mg/Al mixed oxides are indeed formed and dispersed on the SBA-15 surface with non-blockage porosity. Furthermore, the physicochemical surface properties are exalted from its precursors and it is synergistically favorable for the BTEX sorption at low pressure and temperature.

Oxidative Refolding of Lysozyme Assisted by DsbA, DsbC and the GroEL Apical Domain Immobilized in Cellulose

Aurora Antonio-Pérez,Tania Rivera-Hernández,Luz María Aldaz-Martínez,Jaime Ortega-López 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

Expression of recombinant proteins in Escherichia coli often leads to formation of inclusion bodies (IB). If a recombinant protein contains one or more disulfide bonds,protein refolding and thiol oxidation reactions are required to recover its biological activity. Previous studies have demonstrated that molecular chaperones and foldases assist with the in vitro protein refolding. However, their use has been limited by the stoichiometric amount required for the refolding reaction. In search of alternatives to facilitate the use of these folding biocatalysts in this study, DsbA, DsbC,and the apical domain of GroEL (AD) were fused to the carbohydrate-binding module CBDCex of Cellulomonas fimi. The recombinant proteins were purified and immobilized in cellulose and used to assist the oxidative refolding of denatured and reduced lysozyme. The assisted refolding yields obtained with immobilized folding biocatalysts were at least twice of those obtained in the spontaneous refolding,suggesting that the AD, DsbA, and DsbC immobilized in cellulose might be useful for the oxidative refolding of recombinant proteins that are expressed as inclusion bodies. In addition, the spontaneous or assisted refolding kinetics data fitted well (r2 > 0.9) to a previously reported lysozyme refolding model. The estimated refolding (kN)and aggregation (kA) constants were consistent with the hypothesis that foldases assisted the oxidative refolding of lysozyme by decreasing protein aggregation rather than increasing the refolding rate.

Diet-induced obese mice exhibit altered immune responses to early Salmonella Typhimurium oral infection

Ricardo Ernesto Ramírez-Orozco,Elena Franco Robles,Victoriano Pérez Vázquez,Joel Ramírez Emiliano,Marco Antonio Hernández Luna,Sergio López Briones 한국미생물학회 2018 The journal of microbiology Vol.56 No.9

Obesity is a chronic disease associated with different metabolic diseases as well as alterations in immune cell function. It is characterized by a chronic systemic low grade inflammation. There are several studies demonstrating the influence of obesity on the impaired immune response to infection. However, it is not completely clear whether the obese environment influences the development or maintenance of the immune response against infections. The aim of this study was to determine how obesity induced by a high-fat diet affects the immune response to an early oral Salmonella infection. Four groups of mice were kept in separate cages. Two of these designated as controls, fed with a normal diet; whereas other two groups were fed with a high fat diet for 10 weeks. Some mice were used for Salmonella oral infection. After 7 days of oral infection with S. Thypimurium the proportions of spleen cell subsets expressing activation markers in normal diet and HFD obese mice were stained with monoclonal antibodies and analyzed by flow cytometry. Also, mRNA levels of different cytokines were quantified by RT-PCR. It was found that obesity affects the function of the immune system against an early oral Salmonella infection, decreasing NK cells, altering the expression of activation molecules as well as cytokines mRNA levels. Interestingly, the expression some activation molecules on T lymphocytes was reestablished after Salmonella infection, but not the CD25 expression. Immune alterations could lead to immunosuppression or increased susceptibility to infections in HFD obese mice.