Evaluation of online learning readiness in the new distance learning normality.

The COVID-19 pandemic influenced teaching and learning in higher education. The transformation towards digital education challenged Faculty and students. This research examines the online learning readiness of students in a Higher Education Institution in Mexico. Specifically, we investigated how much prior digital skills, as well as having used the digital resources available by the university, influenced their academic achievement in distance learning settings. Seven dimensions of online learning readiness were selected to evaluate the student's preparation for the online learning process. Questionnaires were applied before the start and at the end of digital courses. Follow-up tools were offered to support the student, and two groups were observed, users and non-users of the digital devices. It was observed that students who used the support developed significantly better critical thinking, problem-solving, and time organization skills than non-users. On the other hand, although the evaluations were not significantly different, the lowest averages were found in the non-user group. Our results indicate that prior training in the use of digital tools is essential for the success of online education; in the same way, a timely follow-up with technical and pedagogical assistance is necessary for developing competencies. Training more autonomous and independent students capable of distance learning in a global world demands experts in digital education urgently. Educational institutions must embrace new technologies and teaching methods to meet the ever-changing needs of students. This research is expected to play a crucial role in promoting constructive discussions and facilitating informed decisions concerning the creation of future educational models.

Advances in Material Modification with Smart Functional Polymers for Combating Biofilms in Biomedical Applications.

Biofilms as living microorganism communities are found anywhere, and for the healthcare sector, these constitute a threat and allied mechanism for health-associated or nosocomial infections. This review states the basis of biofilms and their formation. It focuses on their relevance for the biomedical sector, generalities, and the major advances in modified or new synthesized materials to prevent or control biofilm formation in biomedicine. Biofilm is conceptualized as an aggregate of cells highly communicated in an extracellular matrix, which the formation obeys to molecular and genetic basis. The biofilm offers protection to microorganisms from unfavorable environmental conditions. The most frequent genera of microorganisms forming biofilms and reported in infections are Staphylococcus spp., Escherichia spp., and Candida spp. in implants, heart valves, catheters, medical devices, and prostheses. During the last decade, biofilms have been most commonly related to health-associated infections and deaths in Europe, the United States, and Mexico. Smart, functional polymers are materials capable of responding to diverse stimuli. These represent a strategy to fight against biofilms through the modification or synthesis of new materials. Polypropylene and poly-N-isopropyl acrylamide were used enough in the literature analysis performed. Even smart polymers serve as delivery systems for other substances, such as antibiotics, for biofilm control.

Analysis of the retention of women in higher education STEM programs.

Gender equity and quality education are Sustainable Development Goals that are present when a culture of equity and inclusion is pursued in society, companies, and institutions. Particularly in undergraduate programs in Science, Technology, Engineering, and Mathematics (STEM), there is a noticeable gender gap between men and women. The objective of this study was to find out the causes of permanence in STEM careers of women, as well as the possible causes of career abandonment towards another STEM or non-STEM career. This was done by analyzing historical data for admission to STEM careers and using an instrument (survey) for data collection carried out in a private university in Mexico. Historical data indicates that only 17% of the total population were women choosing a STEM career. A survey was carried out for 3 months to obtain information on the factors that affect the decision to opt for a STEM career or to remain in it. It was found that men and women prefer inspiring Faculty who motivate them to continue their careers. Factors such as the competitive environment and the difficulty of teaching with less empathetic Faculty were negative and decisive aspects of decision-making. School achievement did not influence the dropout rate of women in STEM careers. The factors of choice and desertion of women in STEM careers were determined, and actions of educational innovation such as mentoring and timely monitoring of already enrolled female students, digital platforms for students and Faculty, awareness workshops for Faculty, and talks with successful women in STEM areas were proposed.

Draft genome sequence of first Vibrio diabolicus in Mexico strain InDRE-D1-M1, an emergent threat.

INTRODUCTION: The complete genome of the marine environmental bacterium Vibrio diabolicus isolated from raw shrimp in the city of Guadalajara in the state of Jalisco in Mexico is reported here. METHODOLOGY: Vibrio spp. it was isolated and identified using standard microbiological and molecular techniques. Whole genome sequencing was performed using the Miseq system (Illumina, USA). RESULTS: The Multi Locus Sequence Typing profile of the isolated Vibrio bacteria coincided only with 4 specific loci (atpA, gyrB, pyrH and recA) and with a total coverage of the species belonging to Vibrio spp. Analysis of the complete genome of the Vibrio isolate and other closely related species, using the genomic fingerprints of the Virtual Analysis Method for PHylogenomic fingerprint estimation (VAMPHyRe) software, revealed the clustering of this species among the clade Vibrio diabolicus. The antibiogram revealed that this strain of Vibrio diabolicus is resistant to ampicillin, which is consistent with the bioinformatic finding of the ß-lactamase enzyme that hydrolyzes carbenicillin class A. CONCLUSIONS: This study demonstrated that the environmental marine bacterium Vibrio diabolicus contains carrier genes associated with pathogenicity and ecological function, which could represent a threat to public health.

Epidemiological surveillance of chikungunya fever in Mexico since its introduction in 2014-2016 and identification of circulating genotypes.

In 2014, the chikungunya virus (CHIKV) was detected for the first time in Mexico, the identified strain was the one corresponding to the Asian genotype which was phylogenetically grouped with the strains that circulated in the British Virgin Islands outbreak and was later classified with lineages of Caribbean strains. In three years, 13,569 cases of chikungunya were registered in Mexico. Although the transmission and spread of the virus are now considered a moderate risk, the danger that the virus reemerges is not ruled out due to the infestation of Aedes mosquitoes. In this study, we reviewed the chikungunya fever (CHIKF) cases reported between 2014 and 2016 to reanalyze the data. Seventeen cases were selected from different states where the circulation of the virus had been reported. Statistical data were analyzed and a retrospective analysis was carried out. Nucleic acid sequences were determined of these 17 samples. 2015 was the year with the highest number of cases (92.8%) and they were detected in 28 states of the country. There is a predominance of females, and the most affected age group was between 25 and 44 years. In 2016, CHIKV genotypes were not known, in this study the presence of the Asian genotype of Caribbean lineage was confirmed. The presence of the West African and ECSA genotypes was phylogenetically ruled out. The sequences obtained were deposited in GeneBank.

Evaluation of serological diagnostic tests of human brucellosis for prevention and control in Mexico.

Brucellosis is a zoonosis mainly present in developing countries. The WHO reports 500,000 new cases every year. From 2012 to 2016, 13,677 cases were reported in Mexico, with 2.00 to 2.64 rate per 100,000 inhabitants. To analyze the diagnostic algorithm of brucellosis in Mexico, we compared the commercial laboratory tests ELISA, Brucellacapt®, and lateral flow test (LFT) in a study of 473 individuals from two endemic Mexican populations. All patients were treated in first-level medical units for presenting brucellosis compatible symptoms and without a history of the disease. Clinical-epidemiological information was gathered and initial serum samples were obtained to react with anti-Brucella antibodies; subsequent samples were collected at follow-up treatment visits. Using the Rose Bengal screening, we found 165 negative samples and 308 positive reactive samples, of which 222 cases were confirmed and 234 were positive on at least one marker (IgG or IgM) or LFT. When Brucellacapt® was used, similar results to those observed with the conventional algorithm were found as judged by the Cohen's kappa coefficient (κ) (0.813, 95% CI 0.7788-0.8472). Similar κ indices between conventional algorithm and ELISA pair were found, 0.7038 (95% CI 0.6555-0.7521), representing high similarity between both groups of diagnosis. We conclude that conventional serodiagnoses, Brucellacapt® and LFT, presented inconclusive results and poor correlation between them. By contrast, ELISA test pair (IgG + IgM) presented high correlation with the conventional algorithm and greater capacity for correct positive and negative classification.

A challenge based learning experience in forensic medicine.

Learning about forensic sciences is a crucial part of the formation of professionals working in medicine and health areas; this includes a range of coverage from legal-medical cases to forensic autopsies. However, knowledge of forensics by medical students is limited, because the teaching focus has been on the fundamentals of procedures in this field. To develop the necessary skills, specific support, and targeted learning tasks should be designed to enable the integration of interdisciplinary work in processes, infrastructure, and equipment used in a high-quality-forensic investigation. The innovative educational experience of the Crime Scene Investigation CSI Lab was a week-long activity using the pedagogical strategy of Challenge-Based Learning. It addresses the problem that students need training in an authentic setting. The intervention, in September 2017, included 33 students from different disciplines such as medicine, law, and marketing. They participated in various learning settings in multidisciplinary teams and were challenged by experts from the State Institute for Forensic Sciences to analyze specific processes. The outcomes of the CSI Lab implementations provided evidence of how the students benefited from the experience. The results showed that 80% of the teams had an excellent approach to the solution, justification of the proposal and feasibility assessment. However, only 60% achieved a solution that met the requirements. The educational process was assessed by their perceptions of the educational strategy of the CSI Lab experience. The results indicated that 88.9% of the students believed that the experience broadened their perspectives on forensic sciences. 73.1% thought that the design of the activities, visits, and plenaries added value to their academic training, and 88.9% found it to be interesting. Regarding whether or not the activities helped the participants to understand and perform a legal-medicine investigation, 92.6% believed that it did help them recognize and understand the interventional areas and processes necessary for the investigation. CONCLUSION: Students demonstrated high acceptance of the context-rich design of the practical activities and educational experiences that were grounded in active learning. The effect on curriculum design is that the interactions and interdisciplinarity of the programs must be assessed, as these experiences could motivate them to engage in solving the social challenges of the 21st century.

Flotillin homologue is involved in the swimming behavior of Escherichia coli.

Cellular membrane is a key component for maintaining cell shape and integrity. The classical membrane structure and function by Singer and Nicolson groundbreaking model has depicted the membrane as a homogeneous fluid structure. This view has changed by the discovery of discrete domains containing different lipid compositions, called lipid rafts, which play a key role in signal transduction in eukaryotic cells. In the past few years, lipid raft-like structures have been found in bacteria also, constituted by cardiolipin and other modified lipids, perhaps involved in generating a specific site for protein clustering. Here, we report the analysis of a protein termed YqiK from Escherichia coli, a prohibitin homolog that has been implicated in stress sensing by the formation of membrane-associated microdomains. The E. coli yqiK-deficient mutant strain showed an enhanced swimming behavior and was resistant to ampicillin but its response to other stressing conditions was similar to that of the wild-type strain. The abnormal swimming behavior is reversed when the protein is expressed in trans from a plasmid. Also, we demonstrate that YqiK is not redundant with QmcA, another flotillin homolog found in E. coli. Our results, along with the data available in the literature, suggest that YqiK may be involved in the formation of discrete membrane-associated signaling complexes that regulate and agglomerate signaling proteins to generate cell response to chemotaxis.

Genotypic variability analysis of DENV-1 in Mexico reveals the presence of a novel Mexican lineage.

Here, we report for the first time the circulation of dengue virus type 1 (DENV-1) belonging to the lineage IV of genotype V (African American genotype) based on phylogenetic analysis of nucleotide sequences from 10 DENV-1-positive samples obtained in Mexico between 2012 and 2014. Our data revealed that the lineages III and IV of DENV-1 genotype V were found circulating during the same period, probably explaining the rise in the number of cases of severe dengue during that period.

Multiple regulators of the Flavohaemoglobin (hmp) gene of Salmonella enterica serovar Typhimurium include RamA, a transcriptional regulator conferring the multidrug resistance phenotype.

Microbial flavohaemoglobins are proteins with homology to haemoglobins from higher organisms, but clearly linked to nitric oxide (NO) metabolism by bacteria and yeast. hmp mutant strains of several bacteria are hypersensitive to NO and related compounds and hmp genes are up-regulated by the presence of NO. The regulatory mechanisms involved in hmp induction by NO and the superoxide-generating agent, methyl viologen (paraquat; PQ), are complex, but progressively being resolved. Here we show for the first time that, in Salmonella enterica serovar Typhimurium, hmp transcription is increased on exposure to PQ and demonstrate that RamA, a homologue of MarA is responsible for most of the hmp paraquat regulation. In addition we demonstrate NO-dependent elevation of Salmonella hmp transcription and Hmp accumulation. In both Escherichia coli and Salmonella modest transcriptional repression of hmp is exerted by the iron responsive transcriptional repressor Fur. Finally, in contrast to previous reports, we show that in E. coli and Salmonella, hmp induction by both paraquat and sodium nitroprusside is further elevated in a fur mutant background, indicating that additional regulators are implicated in this control process.

Spent media from cultures of environmental isolates of Escherichia coli can suppress the deficiency of biofilm formation under anoxic conditions of laboratory E. coli strains.

The prevailing lifestyle of bacteria is sessile and they attach to surfaces in structures known as biofilms. In Escherichia coli, as in many other bacteria, biofilms are formed at the air-liquid interface, suggesting that oxygen has a critical role in the biofilm formation process. It has been reported that anaerobically growing E. coli laboratory strains are unable to form biofilms even after 96 h of incubation on Luria Bertani (LB) medium. After analyzing 22,000 transposon-induced and 26,000 chemically-induced mutants we failed to isolate an E. coli laboratory strain with the ability to form biofilm under anaerobic growth conditions. Notably, seven strains from a collection of E. coli isolated from different hosts and the environment had the ability to form biofilm in the absence of oxygen. Interestingly, spent medium from cultures of one strain, Souza298, can promote biofilm formation of E. coli laboratory strains growing under anaerobic conditions. Our results led us to propose that laboratory E. coli strains do not release (or synthesize) a molecule needed for biofilm formation under anoxic conditions but that they bear all the required machinery needed for this process.

Effect of anaerobic and stationary phase growth conditions on the heat shock and oxidative stress responses in Escherichia coli K-12.

The natural living style of Escherichia coli occurs in the gastrointestinal tract, where most of its existence is spent under anaerobic conditions and in stationary phase of growth. Here we report on the heat shock response of E. coli K-12 cells growing in the presence or absence of oxygen. An rpoH mutant (impaired in the synthesis of the sigma(32) transcriptional factor) exhibited an increased sensitivity to heat shock but only in the exponential phase of aerobic growth, suggesting that in anaerobic growth conditions, and in aerobic stationary phase, sigma(32)-independent mechanisms are playing a prime role in protecting cells from heat stress. Our results demonstrated that sigma(S) is not involved in this protection system. Studies on the kinetics of synthesis of Heat shock proteins (Hsp) after an abrupt rise in temperature demonstrated that in the absence of oxygen, the synthesis of Hsp is triggered faster and is sustained for a longer period of time compared to aerobic growth conditions. Finally, the heated cells in the exponential phase of aerobic growth displayed a high concentration of oxidatively damaged proteins in the presence of 4 mM H(2)O(2), in sharp contrast to cultures of stationary phase or anaerobic growth.

Genome-wide transcriptional profile of Escherichia coli in response to high levels of the second messenger 3',5'-cyclic diguanylic acid.

Cyclic diguanylic acid (c-di-GMP; cGpGp) is a global second messenger controlling motility and adhesion in bacterial cells. Intracellular concentrations of c-di-GMP depend on two opposite activities: diguanylate cyclase, recently assigned to the widespread GGDEF domain, and c-di-GMP-specific phosphodiesterase, associated with proteins harboring the EAL domain. To date, little is known about the targets of c-di-GMP in the cell or if it affects transcriptional regulation of certain genes. In order to expand our knowledge of the effect of this molecule on the bacterial metabolism, here we report on the Escherichia coli transcriptional profile under high levels of c-di-GMP. We show that an important number of genes encoding cell surface and membrane-bound proteins are altered in their transcriptional activity. On the other hand, genes encoding several transcriptional factors, such as Fur, RcsA, SoxS, and ZraR, are up-regulated, and others, such as GadE, GadX, GcvA, and MetR, are down-regulated. Transcription of motility and cell division genes were altered, and consistent with this was the physiological analysis of cells overexpressing yddV, a diguanylate cyclase; these cells displayed an abnormal cell division process when high levels of c-di-GMP were present. We also show evidence that the diguanylate cyclase gene yddV is co-transcribed with dos, a heme base oxygen sensor with c-di-GMP-specific phosphodiesterase activity. A delta dos::kan mutation rendered the cells unable to divide properly, suggesting that dos and yddV may be part of a fine-tuning mechanism for regulating the intracellular levels of c-di-GMP.

[Proteins with GGDEF and EAL domains: their role in bacterial metabolism]. / Proteínas con dominios GGDEF y EAL: su función en el metabolismo bacteriano.

The availability of multiple bacterial genome sequences has led to the discovery of several conserved domains of proteins. Recently, GGDEF and EAL domains have been described as domains responsible for the synthesis and degradation of c-di-GMP, a second messenger in bacteria. c-di-GMP has been involved in cellulose production and identified as a global regulator of several processes such as biofilm formation, motility and virulence, presumibly through a modification of the cell surface properties.

Anaerobic growth does not support biofilm formation in Escherichia coli K-12.

Association with a surface in a structure known as biofilm is the prevailing microbial lifestyle. Here we show the kinetics of biofilm formation of Escherichia coli W3110 in static cultures growing under aerobic or anaerobic conditions. Aerobically growing cells in LB medium started to produce detectable amounts of biofilm after 4 to 8 h, displaying maximal accumulation of formed biofilm at 24 h, corresponding to the onset of stationary phase. Then an abrupt reduction in the biomass of the biofilm was observed. This decrease was not prevented by external addition of fresh nutrients and coincided with the depletion of oxygen as measured by the enzymatic activity of the AdhE protein. No biofilm formation was detected in cultures grown anaerobically in LB or LB supplemented with nitrate, nitrite, DMSO or fumarate, even after 72 h of incubation, well inside the stationary phase, suggesting that under anaerobic growth conditions E. coli cannot form biofilms.

A novel double heme substitution produces a functional bo3 variant of the quinol oxidase aa3 of Bacillus cereus. Purification and paratial characterization.

A novel bo3-type quinol oxidase was highly purified from Bacillus cereus PYM1, a spontaneous mutant unable to synthesize heme A and therefore spectroscopically detectable cytochromes aa3 and caa3. The purified enzyme contained 12.4 nmol of heme O and 11.5 nmol of heme B mg-1 protein. The enzyme was composed of two subunits with an Mr of 51,000 and 30,000, respectively. Both subunits were immunoreactive to antibodies raised against the B cereus aa3 oxidase. Moreover, amino-terminal sequence analysis of the 30-kDa subunit revealed that the first 19 residues were identical to those from the 30-kDa subunit of the B. cereus aa3 oxidase. The purified bo3 oxidase failed to oxidize ferrrocytochrome c (neither yeast nor horse) but oxidized tetrachlorohydroquinol with an apparent Km of 498 microM, a Vmax of 21 micromol of O2 min-1mg-1, and a calculated turnover of 55 s-1. The quinol oxidase activity with tetrachlorohydroquinol was inhibited by potassium cyanide and 2-n-heptyl 4-hydroxyquinoline-N-oxide with an I50 of 24 and 300 microM, respectively. Our results demonstrate that the bo3 oxidase of this mutant is not the product of a new operon but instead is a cytochrome aa3 apoprotein encoded by the qox operon of the aa3 oxidase of B. cereus wild type promiscuously assembled with hemes B and O replacing heme A, producing a novel bo3 cytochrome. This is the first reported example of an enzymatically active promiscuous oxidase resulting from the simultaneous substitution of its original hemes in the high and low spin sites.

Flavohemoglobin Hmp, but not its individual domains, confers protection from respiratory inhibition by nitric oxide in Escherichia coli.

Escherichia coli possesses a two-domain flavohemoglobin, Hmp, implicated in nitric oxide (NO) detoxification. To determine the contribution of each domain of Hmp toward NO detoxification, we genetically engineered the Hmp protein and separately expressed the heme (HD) and the flavin (FD) domains in a defined hmp mutant. Expression of each domain was confirmed by Western blot analysis. CO-difference spectra showed that the HD of Hmp can bind CO, but the CO adduct showed a slightly blue-shifted peak. Overexpression of the HD resulted in an improvement of growth to a similar extent to that observed with the Vitreoscilla hemeonly globin Vgb, whereas the FD alone did not improve growth. Viability of the hmp mutant in the presence of lethal concentrations of sodium nitroprusside was increased (to 30% survival after 2 h in 5 mM sodium nitroprusside) by overexpressing Vgb or the HD. However, maximal protection was provided only by holo-Hmp (75% survival under the same conditions). Cellular respiration of the hmp mutant was instantaneously inhibited in the presence of 13.5 microM NO but remained insensitive to NO inhibition when these cells overexpressed Hmp. When HD or FD was expressed separately, no significant protection was observed. By contrast, overexpression of Vgb provided partial protection from NO respiratory inhibition. Our results suggest that, despite the homology between the HD from Hmp and Vgb (45% identity), their roles seem to be quite distinct.

Plasmid DNA supercoiling and gyrase activity in Escherichia coli wild-type and rpoS stationary-phase cells.

Stationary-phase cells displayed a distribution of relaxed plasmids and had the ability to recover plasmid supercoiling as soon as nutrients became available. Preexisting gyrase molecules in these cells were responsible for this recovery. Stationary-phase rpoS cells showed a bimodal distribution of plasmids and failed to supercoil plasmids after the addition of nutrients, suggesting that rpoS plays a role in the regulation of plasmid topology during the stationary phase.

A mutation in rpoS enhances biofilm formation in Escherichia coli during exponential phase of growth.

Biofilm formation in Escherichia coli is a process that involves slow growth and stress conditions where several molecular signals and growth phase regulated genes are involved. Here we show that rpoS mutant strains (defective in the stress regulator sigma(S)) exhibit an increased production of biofilm, especially in the exponential phase of growth. Our results indicate that rpoS mutants produce an extracellular factor that promotes the production of biofilm during the exponential phase of growth. Thus, RpoS plays an important role in the regulation of the amount and initiation of biofilm formation in E. coli.