Evaluation of functional characteristics of Acidithiobacillus thiooxidans microencapsulated in gum arabic by spray-drying as biotechnological tool in the mining industry.

The mining and metallurgical industry represents one of the leading causes of environmental pollution. In this context, the optimization of mineral waste management and the efficient extraction of metals of interest becomes an imperative priority for a sustainable future. Microorganisms such as Acidithiobacillus thiooxidans have represented a sustainable and economical alternative in recent years due to their capacity for environmental remediation in bioleaching processes because of their sulfur-oxidizing capacity and sulfuric acid generation. However, its use has been limited due to the reluctance of mine operators because of the constant reproduction of the bacterial culture in suitable media and the care that this entails. In this work, the central objective was to evaluate the functional characteristics of A. thiooxidans, microencapsulated and stored at room temperature for three years in vacuum bags, using a spray drying process with gum arabic as a wall vector. Growth kinetics showed a survival of 80 ± 0.52% after this long period of storage. Also, a qualitative fluorescence technique with a 5-cyano-2-3 ditolyl tetrazolium (CTC) marker was used to determine the respiratory activity of the microorganisms as soon as it was resuspended. On the other hand, the consumption of resuspended sulfur was evaluated to corroborate the correct metabolic functioning of the bacteria, with results of up to 50% sulfur reduction in 16 days and sulfate generation of 513.85 ± 0.4387 ppm and 524.15 ± 0.567 ppm for microencapsulated and non-microencapsulated cultures, respectively. These results demonstrate the success after three years of the microencapsulation process and give guidelines for its possible application in the mining-metallurgical industry.

Expression and characterization of a novel ß-1,4-endoglucanase from Bacillus subtilis strain isolated from a pulp and paper mill wastewater.

The production of fermentable sugars from lignocellulosic biomass is achieved by the synergistic action of a group of enzymes called cellulases. Cellulose is a long chain of chemically linked glucoses by ß-1,4 bonds. The enzyme ß-1,4-endoglucanase is the first cellulase involved in the degradation, breaking the bond of the amorphous regions. A ß-1,4-endoglucanase enzyme with high activity was obtained from a Bacillus subtilis strain isolated from wastewater of a pulp and paper mill. Sequencing and bioinformatic analysis showed that the gene amplified by PCR consisting of 1407 nucleotides and coding for a ß-1,4-endoglucanase enzyme of approximately 55 kDa. The open reading frame (ORF) encoding the mature endoglucanase (eglS) was successfully inserted in a modified cloning plasmid (pITD03) and into the pYD1 plasmid used for its expression in yeast. Carboxymethylcellulose (CMC) plate assay, SDS-PAGE, and zymogram confirmed the production and secretion by the transformed E. coli BL21-SI strain of a 39 kDa ß-1,4-endoglucanase consistent with the catalytic domain without the cellulose-binding module (CBM). The results showed that the truncated ß-1,4-endoglucanase had higher activity and stability.

Risk Factors Associated with COVID-19 Mortality in the State of Durango, Mexico.

The coronavirus disease 2019 (COVID-19) has caused over six million deaths worldwide since its emergence in Wuhan China, factors associated with COVID-19 mortality, such as comorbidities, age, and observed symptomatology still remain a major subject of study. In the present work, a total of 16,345 SARS-CoV-2 positive cases from Durango Mexico diagnosed from May 2020 to December 2021 were analyzed to establish an association of COVID-19 mortality with clinical and demographic variables in a case-control study. Selected variables include patient age, smoking status, sex, presence of comorbidities such as hypertension, diabetes and obesity, as well as patient symptomatology such as fever, dyspnea, abdominal pain and diarrhea. Results indicate that among analyzed data, the median age was 43 years; 54% were female, with a mortality rate of 5.66%. Multivariate regression analysis indicated that the comorbidities associated with the highest risk factor were advanced age (>60) with an odds ratio of 4.127 (IC 95%, 3.37-5.05), hypertension with 1.961 (IC 95%, 1.57-2.45), diabetes with 1.753 (IC 95%, 1.39-2.20) and obesity with 1.413 (IC 95%, 1.11-1.78) respectively. On the other hand, the symptom associated with the highest risk factor was dyspnea with an odds ratio of 18.369 (IC 95%, 14.42-23.39). Our data suggests an association between hypertension and old age with COVID-19 mortality. Other findings include the prevalence of dyspnea, polypnea and cyanosis as a major predictor for COVID-19 mortality, as well as lower mortality risks among health workers.

Improvement of zero waste sustainable recovery using microbial energy generation systems: A comprehensive review.

Microbial energy generation systems, i.e., bioelectrochemical systems (BESs) are promising sustainable technologies that have been used in different fields of application such as biofuel production, biosensor, nutrient recovery, wastewater treatment, and heavy metals removal. However, BESs face great challenges such as large-scale application in real time, low power performance, and suitable materials for their configuration. This review paper aimed to discuss the use of BES systems such as conventional microbial fuel cells (MFCs), as well as plant microbial fuel cell (P-MFC), sediment microbial fuel cell (S-MFC), constructed wetland microbial fuel cell (CW-MFC), osmotic microbial fuel cell (OsMFC), photo-bioelectrochemical fuel cell (PBFC), and MFC-Fenton systems in the zero waste sustainable recovery process. Firstly, the configuration and electrode materials used in BESs as the main sources to improve the performance of these technologies are discussed. Additionally, zero waste recovery process from solid and wastewater feedstock, i.e., energy recovery: electricity generation (from 12 to 26,680 mW m-2) and fuel generation, i.e., H2 (170 ± 2.7 L-1 L-1 d-1) and CH4 (107.6 ± 3.2 mL-1 g-1), nutrient recovery of 100% (PO43-P), and 13-99% (NH4+-N), heavy metal removal/recovery: water recovery, nitrate (100%), sulfate (53-99%), and sulfide recovery/removal (99%), antibiotic, dye removal, and other product recovery are critically analyzed in this review paper. Finally, the perspective and challenges, and future outlook are highlighted. There is no doubt that BES technologies are an economical option for the simultaneous zero waste elimination and energy recovery. However, more research is required to carry out the large-scale application of BES, as well as their commercialization.

Expression of a ß-glucosidase from Trichoderma reesei in Escherichia coli using a synthetic optimized gene and stability improvements by immobilization using magnetite nano-support.

The enzymatic conversion of lignocellulosic biomass to fermentable sugars is determined by the enzymatic activity of cellulases; consequently, improving enzymatic activity has attracted great interest in the scientific community. Cocktails of commercial cellulase often have low ß-glucosidase content, leading to the accumulation of cellobiose. This accumulation inhibits the activity of the cellulolytic complex and can be used to determine the enzymatic efficiency of commercial cellulase cocktails. Here, a novel codon optimized ß-glucosidase gene (B-glusy) from Trichoderma reesei QM6a was cloned and expressed in three strains of Escherichia coli (E. coli). The synthetic sequence containing an open reading frame (ORF) of 1491 bp was used to encode a polypeptide of 497 amino acid residues. The ß-glucosidase recombinant protein that was expressed (57 kDa of molecular weight) was purified by Ni agarose affinity chromatography and visualized by SDS-PAGE. The recombinant protein was better expressed in E. coli BL21 (DE3), and its enzymatic activity was higher at neutral pH and 30 °C (22.4 U/mg). Subsequently, the ß-glucosidase was immobilized using magnetite nano-support, after which it maintained >65% of its enzymatic activity from pH 6 to 10, and was more stable than the free enzyme above 40 °C. The maximum immobilization yield had enzyme activity of 97.2%. In conclusion, ß-glucosidase is efficiently expressed in the microbial strain E. coli BL21 (DE3) grown in a simplified culture medium.

Mechanisms associated to apoptosis of cancer cells by phenolic extracts from two canned common beans varieties (Phaseolus vulgaris L.).

Two varieties of common beans (Phaseolus vulgaris L.), Bayo Victoria and Negro 8025, were evaluated to determine the effect on cellular viability and mechanisms involved in apoptosis pathways, using a cellular model with HT-29 cells. Aqueous methanolic (50:50) extracts from cooked beans were analyzed for phenolic composition, identifying greater diversity of phenolic compounds in Bayo Victoria extracts. However, Negro 8025 showed greater phenolic content and cytotoxicity effects at lower media inhibitory concentrations, and greater effectiveness to activate apoptotic pathways. Proteins related to the arrest of cell cycle were modulated by both bean cultivars. Qualitative analysis by HPLC-PAD and HPLC-MS systems of phenolic compounds in common bean extracts showed mainly hydroxybenzoic and hydroxycinnamic acids, flavonols, and monomeric flavan-3-ols. Bioactive phenolics such as catechin, kaempferol, and ferulic acid were found in both cultivars as well anticancer phytochemicals such as quercetin, protocatechuic acid, myricetin, naringenin and their derivatives, and procyanidins. PRACTICAL APPLICATIONS: Polyphenols in common beans (Phaseolus vulgaris L.) cultivars processed by canning display chemoprotective potential as they activate mechanisms involved in apoptosis pathways. Phenolics in common beans modulate 28 proteins related to apoptotic processes. Therefore, a diet including canned beans (particularly darker varieties) might represent health benefits and cancer-preventive effects.

Simultaneous removal of Cd2+ and Zn2+ from aqueous solution using an upflow Al-electrocoagulation reactor: optimization by response surface methodology.

The presence of heavy metals in the environment has increased, and cadmium (Cd) and zinc (Zn) are considered to be among the most dangerous. An upflow Al-electrocoagulation reactor was used to remove Cd2+ and Zn2+ ions from aqueous media. The system consisted of perforated aluminum circular electrodes for fluid distribution with elimination of external agitation. The effect of different parameters, i.e. current intensity, electrolysis time, concentration of Cd2+ and Zn2+ ions and electrolytic support dose were optimized by response surface methodology. The results indicated that increasing the current intensity and the electrolysis time had a positive effect on the elimination efficiency of the pollutant ions. Likewise, increasing the dose of electrolytic support and decreasing the concentration of the pollutants improved the efficiency of the system. The optimal results were: current intensity of 0.4 A, electrolysis time of 40 min, ion concentration of 44.6 mg·L-1 and electrolytic support dose of 0.56 mg·L-1, with the maximum elimination percentages of 96 ± 3.8% and 96 ± 2.7% for Cd2+ and Zn2+, respectively. This study showed that the electrocoagulation process in an upflow electrocoagulation reactor could be successfully applied to remove pollutants from water.

Study of the Enzymatic Capacity of Kluyveromyces marxianus for the Synthesis of Esters.

Recently, biotechnological opportunities have been found in non-Saccharomyces yeasts because they possess metabolic characteristics that lead to the production of compounds of interest. It has been observed that Kluyveromyces marxianus has a great potential in the production of esters, which are aromatic compounds of industrial importance. The genetic bases that govern the synthesis of esters include a large group of enzymes, among which the most important are alcohol acetyl transferases (AATases) and esterases (AEATases), and it is known that some are present in K. marxianus, because it has genetic characteristics like S. cerevisiae. It also has a physiology suitable for biotechnological use since it is the eukaryotic microorganism with the fastest growth rate and has a wide range of thermotolerance with respect to other yeasts. In this work, the enzymatic background of K. marxianus involved in the synthesis of esters is analyzed, based on the sequences reported in the NCBI database.

Acyclic nucleoside phosphonates: a study on cytochrome P450 gene expression.

1. Nucleotide analogues comprise an important class of drugs used in treatment of viral infections but also cancer. These drugs affect the structural integrity of DNA and activate different pathways and processes in the cell and may directly or indirectly influence the drug metabolizing system. Adefovir dipivoxil (AD) and tenofovir disoproxil (TD) are nucleotide analogues approved for the treatment of chronic hepatitis B and/or HIV/AIDS infection. 2. To evaluate the risk of their drug-drug interactions on the level of drug metabolism, an effect of both compounds on cytochromes P450 expression was studied using cDNA microarrays, real-time RT-PCR and immunoblotting. Mice were given intraperitoneally 25 mg/kg of AD or TD, respectively. As a positive control, a combination of prototypic cytochromes P450 (CYP) inducers, phenobarbital and ß-naphthoflavone was chosen. 3. The data obtained showed a significant CYP induction in the positive control group, but no clinically significant induction of CYP genes by AD or TD was observed. Our results support the evidence of safety of AD and TD with respect to drug-drug interactions based on enzyme induction. These findings are important as a plethora of new antivirals of different types are being tested and introduced to clinical practice, mostly to be used in combinations.

HER2 in gastric cancer: an immunohistochemical study on tissue microarrays and the corresponding whole-tissue sections with a supplemental fish study.

Since focal HER2 expression is an issue in GC, TMA construction from the paraffin-embedded surgically-obtained tissue may not reflect its real status. The aim of this study was to assess the HER2 status in tissue microarrays (TMAs) and the corresponding whole sections using HercepTest immunohistochemistry (IHC), and to correlate it and to assess the concordance of HER2 IHC and fluorescence in situ hybridization (FISH) in TMAs. Concordance of the HER2 expression status for 302 cases of gastric cancer using 9 paired TMAs was evaluated using a 2-mm core size and 305 corresponding whole sections. Concordance of the IHC and FISH HER2 status was compared. In addition,, the HER2 status was compared to clinicopathological characteristics and patients' survival. Using the whole-section approach, HER2 over-expression was found in 25.2 % (HER2 3+ 6.6 %, HER2 2+ 18.7 %) of tumours. The overall concordance of IHC between the cores and the whole section was 84.9 %; 15.1 % of the tumours showed HER2 amplification. The overall concordance of IHC and FISH on cores was 75.7 %. The level of amplification correlated with the IHC score. Relationship between the intestinal and papillary types and tumour grade was observed for tumours with over-expression and amplification, whereas tumour location was related only to over-expression. There was a statistically significant difference in the overall survival of the patients, which was related to HER2 amplification. In conclusion, good concordance of the IHC HER2 results between tissue cores in TMA and whole sections, and excellent concordance of the IHC and FISH results on tissue cores was found. At least a part of the observed IHC HER2 heterogeneity could very likely be explained by fixation artifacts. With adequate fixation, a higher concordance of IHC HER2 between the cores and the whole sections can be expected. The TMA approach could enable an easier analysis of more than one representative tumour block.

Localización de Serratia marcescens en perfil bacteriológico y fúngico de la conjuntiva de caballos clínicamente sanos en Monterrey, Nuevo León, México / Localization of Serratia marcescens in bacterial and fungal profile of conjunctiva of clinically healthy horses from Monterrey, Nuevo Leon, Mexico

The conjunctival normal microflora, formed by fungi, yeast and bacteria, of 50 clinically healthy horses from Monterrey, Nuevo Leon, was identified using three to 12 year-old horses of different breeds and gender. Samples were taken from the conjunctival sac of both eyes (n =100 eyes) using a cotton swab under sterile conditions. No eye was negative to the presence of the microorganism. There were differences in colony types in each eye of the same animal. One hundred percent were positive to fungal and bacteria colonies in both eyes, while 60% were positive to yeast. In the present study Serratia marcescens, a pathogenic, opportunist and multidrug-resistant organism, is reported for the first time in the conjunctival sac in horses. Serratia marcescens was isolated from 21 clinically healthy horses (42%) with a number of colony forming units (cfu) that ranged from 9 to 42.

Se identificó la microflora normal, formada por hongos, levaduras y bacterias, de la conjuntiva en 50 caballos clínicamente sanos, de diferente raza y sexo, de tres a 12 años de edad, del área metropolitana de Monterrey, Nuevo León. Las muestras se tomaron del saco conjuntival de ambos ojos (n = 100 ojos) con un hisopo bajo condiciones estériles. Ningún ojo fue negativo a la presencia de microorganismos. Hubo a menudo diferencias en los tipos de colonias entre los ojos del mismo animal, 100% fueron positivos a la presencia de hongos y bacterias en ambos ojos, y 60% positivos a la presencia de levaduras. Este estudio presenta, por vez primera en conjuntiva de caballos, la presencia de Serratia marcescens, considerada microorganismo patógeno oportunista con multirresistencia a fármacos. En esta investigación, Serratia marcescens se logró aislar de 21 caballos clínicamente sanos (42%) con rango de nueve a 42 unidades formadoras de colonias (ufc).

The testicular form of hormone-sensitive lipase HSLtes confers rescue of male infertility in HSL-deficient mice.

Inactivation of the hormone-sensitive lipase gene (HSL) confers male sterility with a major defect in spermatogenesis. Several forms of HSL are expressed in testis. HSLtes mRNA and protein are found in early and elongated spermatids, respectively. The other forms are expressed in diploid germ cells and interstitial cells of the testis. To determine whether the absence of the testis-specific form of HSL, HSLtes, was responsible for the infertility in HSL-null mice, we generated transgenic mice expressing HSLtes under the control of its own promoter. The transgenic animals were crossed with HSL-null mice to produce mice deficient in HSL in nongonadal tissues but expressing HSLtes in haploid germ cells. Cholesteryl ester hydrolase activity was almost completely blunted in HSL-deficient testis. Mice with one allele of the transgene showed an increase in enzymatic activity and a small elevation in the production of spermatozoa. The few fertile hemizygous male mice produced litters of very small to small size. The presence of the two alleles led to a doubling in cholesteryl ester hydrolase activity, which represented 25% of the wild type values associated with a qualitatively normal spermatogenesis and a partial restoration of sperm reserves. The fertility of these mice was totally restored with normal litter sizes. In line with the importance of the esterase activity, HSLtes transgene expression reversed the cholesteryl ester accumulation observed in HSL-null mice. Therefore, expression of HSLtes and cognate cholesteryl ester hydrolase activity leads to a rescue of the infertility observed in HSL-deficient male mice.

Hormone-sensitive lipase null mice exhibit signs of impaired insulin sensitivity whereas insulin secretion is intact.

Lipid metabolism plays an important role in glucose homeostasis under normal and pathological conditions. In adipocytes, skeletal muscle, and pancreatic beta-cells, lipids are mobilized from acylglycerides by the hormone-sensitive lipase (HSL). Here, the consequences of a targeted disruption of the HSL gene for glucose homeostasis were examined. HSL null mice were slightly hyperglycemic in the fasted, but not fed state, which was accompanied by moderate hyperinsulinemia. During glucose challenges, however, disposal of the sugar was not affected in HSL null mice, presumably because of release of increased amounts of insulin. Impaired insulin sensitivity was further indicated by retarded glucose disposal during an insulin tolerance test. A euglycemic hyperinsulinemic clamp revealed that hepatic glucose production was insufficiently blocked by insulin in HSL null mice. In vitro, insulin-stimulated glucose uptake into soleus muscle, and lipogenesis in adipocytes were moderately reduced, suggesting additional sites of insulin resistance. Morphometric analysis of pancreatic islets revealed a doubling of beta-cell mass in HSL null mice, which is consistent with an adaptation to insulin resistance. Insulin secretion in vitro, examined by perifusion of isolated islets, was not impacted by HSL deficiency. Thus, HSL deficiency results in a moderate impairment of insulin sensitivity in multiple target tissues of the hormone but is compensated by hyperinsulinemia.

Mutational analysis of the hormone-sensitive lipase translocation reaction in adipocytes.

Lipolysis in adipocytes governs the release of fatty acids for the supply of energy to various tissues of the body. This reaction is mediated by hormone-sensitive lipase (HSL), a cytosolic enzyme, and perilipin, which coats the lipid droplet surface in adipocytes. Both HSL and perilipin are substrates for polyphosphorylation by protein kinase A (PKA), and phosphorylation of perilipin is required to induce HSL to translocate from the cytosol to the surface of the lipid droplet, a critical step in the lipolytic reaction (Sztalryd C., Xu, G., Dorward, H., Tansey, J. T., Contreras, J.A, Kimmel, A. R., and Londos, C. (2003) J. Cell Biol. 161, 1093-1103). In the present paper we demonstrate that phosphorylation at one of the two more recently discovered PKA sites within HSL, serines 659 and 660, is also required to effect the translocation reaction. Translocation does not occur when these serines residues are mutated simultaneously to alanines. Also, mutation of the catalytic Ser-423 eliminates HSL translocation, showing that the inactive enzyme does not migrate to the lipid droplet upon PKA activation. Thus, HSL translocation requires the phosphorylation of both HSL and perilipin.

Hormone-sensitive lipase is a cholesterol esterase of the intestinal mucosa.

The identity of the enzymes responsible for lipase and cholesterol esterase activities in the small intestinal mucosa is not known. Because hormone-sensitive lipase (HSL) catalyzes the hydrolysis of acylglycerols and cholesteryl esters, we sought to determine whether HSL could be involved. HSL mRNA and protein were detected in all segments of the small intestine by Northern and Western blot analyses, respectively. Immunocytochemistry experiments revealed that HSL was expressed in the differentiated enterocytes of the villi and was absent in the undifferentiated cells of the crypt. Diacylglycerol lipase and cholesterol esterase activities were found in the different segments. Analysis of gut from HSL-null mice showed that diacylglycerol lipase activity was unchanged in the duodenum and reduced in jejunum. Neutral cholesterol esterase activity was totally abolished in duodenum, jejunum, and ileum of HSL-null mice. Analysis of HSL mRNA structure showed two types of transcripts expressed in equal amounts with alternative 5'-ends transcribed from two exons. This work demonstrates that HSL is expressed in the mucosa of the small intestine. The results also reveal that the enzyme participates in acylglycerol hydrolysis in jejunal enterocytes and cholesteryl ester hydrolysis throughout the small intestine.

Hormone-sensitive lipase is not required for cholesteryl ester hydrolysis in macrophages.

Storage of cholesteryl esters in the cytoplasm of macrophages is one of the earliest and most ubiquitous event observed in the development of arteriosclerosis. Macrophages have an enormous capacity to uptake and store cholesterol in the form of cytosolic cholesteryl ester droplets. These stores are mobilized by the action of a neutral cholesteryl ester hydrolase (NCEH), producing free cholesterol that is either secreted to extracellular acceptors or reesterified. It has been proposed that hormone-sensitive lipase (HSL) is responsible for the NCEH activity in macrophages. The present work shows, however, that peritoneal macrophages from HSL null mice hydrolyze cytosolic stores of cholesteryl esters at a comparable rate to that of peritoneal macrophages from wild-type mice, therefore demonstrating that HSL is not the main NCEH in macrophages.

Instalaciones automatizadas en la clínica dental [I] / Automated installations in the dental clinic [I]

el gran desarrollo alcanzado por la tecnología electrónica plasmado en uno de sus componentes más prestigiosos, el microprocesador, ha permitido la realización de sistemas electrotécnicos basados en las denominadas aplicaciones inteligentes Estas aplicaciones introducidas en las instalaciones de la clínica dental, aportan unas ventajas sustanciales tanto a los procesos de control y monitorización como a la gestión efectiva de la energía consumida. El rápido desarrollo del concepto de programación junto a los grandes logros tecnológicos alcanzados en la integración de unos componentes electrónicos llamados transis-tores, prepararon el camino para la llegada del microprocesador al principio de los 70. Este circuito integrado tiene ta ventaja de ser programable y constituye una parte fundamental en los sistemas diseñados para la realización de instalaciones automatizadas (AU)