Papers by Dra. Alma Lilián Guerrero Barrera
Environmental Earth Sciences, 2020
Single extraction and sequential extraction assays were used to compare the effect of low-tempera... more Single extraction and sequential extraction assays were used to compare the effect of low-temperature biochar and its nonpyrolyzed composted biosolids on Pb and Cd mobility in the buffered conditions of calcareous river sediments. Results showed that amendment reduced the mobility of both metals, though under higher pH conditions, the effect of the nonpyrolyzed composted biosolids on the mobility of Pb was more apparent. On the other hand, the low temperature biochar had a more significant effect on the mobility of both metals under low pH conditions. The single extraction scheme used to simulate varying physicochemical conditions confirmed that amendment decreased Pb mobility up to 49% and Cd up to 96%. Sequential extraction assays confirmed a shift in predominant metal-fraction associations; from potentially mobile fractions to the more immobile ferromanganese oxide and organic matter fractions. These results highlighted the significant impact biochar amendment can have on metal mobility even when temporarily buffered by the physicochemical conditions in the calcareous substrates.
International Journal of Molecular Sciences, 2020
TagB, TagC (tandem autotransporter genes B and C), and Sha (Serine-protease hemagglutinin autotra... more TagB, TagC (tandem autotransporter genes B and C), and Sha (Serine-protease hemagglutinin autotransporter) are recently described members of the SPATE (serine protease autotransporters of Enterobacteriaceae) family. These SPATEs can cause cytopathic effects on bladder cells and contribute to urinary tract infection in a mouse model. Bladder epithelial cells form an important barrier in the urinary tract. Some SPATEs produced by pathogenic E. coli are known to breach the bladder epithelium. The capacity of these newly described SPATEs to alter bladder epithelial cells and the role of the serine protease active site were investigated. All three SPATE proteins were internalized by bladder epithelial cells and altered the distribution of actin cytoskeleton. Sha and TagC were also shown to degrade mucin and gelatin respectively. Inactivation of the serine catalytic site in each of these SPATEs did not affect secretion of the SPATEs from bacterial cells, but abrogated entry into epithelial cells, cytotoxicity, and proteolytic activity. Thus, our results show that the serine catalytic triad of these proteins is required for internalization in host cells, actin disruption, and degradation of host substrates such as mucin and gelatin.
Frontiers in Veterinary Science, 2020
Actinobacillus pleuropneumonia is a swine (host) specific respiratory pathogen and the etiologica... more Actinobacillus pleuropneumonia is a swine (host) specific respiratory pathogen and the etiological agent of swine pleuropneumonia which affects pigs of all ages, many being asymptomatic carriers. This pathogen has high morbidity and mortality rates which generates large economic losses for the pig industry. Actinobacillus pleuropneumoniae is a widely studied bacterium, however its pathogenesis is not yet fully understood. The prevalence of the 18 serotypes of A. pleuropneumoniae varies by geographic region, in North American area, more specifically in Mexico, serotypes 1, 3, 5b, and 7 show higher prevalence. Actinobacillus pleuropneumoniae is described as a strict extracellular pathogen with tropism for lower respiratory tract. However, this study depicts the ability of these serotypes to adhere to non-phagocytic cells, using an endothelial cell model, as well as their ability to internalize them, proposing it could be considered as an intracellular pathogen.
Trends in Developmental Biology, 2019
Mesenchymal stem cells (MSCs) are nonspecialized cells that have the property of selfrenewal and ... more Mesenchymal stem cells (MSCs) are nonspecialized cells that have the property of selfrenewal and differ in several ways from specialized cells. They are identified in a large number of adult tissues, such as skin, adipose tissue, peripheral blood, bone marrow, pancreas, intestine, brain,
Mesenchymal stem cells are present in adult tissues such as the human dental pulp. They are pluri... more Mesenchymal stem cells are present in adult tissues such as the human dental pulp. They are pluripotent and can differentiate into various specialized cell types in vitro through appropriate stimuli. Ameloblasts produce human tooth enamel only during embryonic development before tooth eruption, so endogenous regeneration is not possible. Various efforts have been aimed at generating natural or artificial substitutes for dental enamel with properties similar to the specific components of said tissue. The purpose of this study was to induce human dental pulp stem cells to produce enamel proteins using extracellular matrix derived from the rat tail tendon and pigskin. Primary cultures of human dental pulp stem cells were established and characterized by RT-PCR and immunofluorescence, using mesenchymal cell markers such as CD14, CD40, CD44, CD105, and STRO-1. The cells were then incubated with the extracellular matrix for fourteen days and labeled with specific antibodies to detect the expression of dental enamel proteins such as amelogenin, ameloblastin, enamelisin, tuftelin, and parvalbumin, characteristics of the phenotype of ameloblasts. This work demonstrated a positive effect of the extracellular matrix to induce the expression of enamel proteins in the stem cells of the human dental pulp.
Trends in Developmental Biology, 2019
Mesenchymal stem cells (MSCs) are nonspecialized cells that have the property of selfrenewal and ... more Mesenchymal stem cells (MSCs) are nonspecialized cells that have the property of selfrenewal and differ in several ways from specialized cells. They are identified in a large number of adult tissues, such as skin, adipose tissue, peripheral blood, bone marrow, pancreas, intestine, brain,
Revista latinoamericana de microbiología, 1995
Salmonella typhimurium LT-2, as Escherichia coli K12, was able to grow in a potassium concentrati... more Salmonella typhimurium LT-2, as Escherichia coli K12, was able to grow in a potassium concentration-dependent manner, down to a very low concentration (< 5 microM). Its metabolic swelling also was [K+]-dependent. When the cells were subjected to hyperosmotic shock, this ion was uptaken rapidly, probably due to a K(+)-high affinity transport-system, similar to the E. coli Kdp system. The shrinkage in presence of 0.6 M NaCl, however, was more noticeable in S. typhimurium, which expressed a smaller level of intracellular K+ than E. coli. The genetic locus responsible for the ability of S. typhimurium to grow in low [K+], was mapped in nitrosoguanidine mutants and localized around min 18, close to the gal operon. This asseveration was confirmed by experiments of reversion, conjugation, and transduction. The mutants required considerably more [K+] to grow and to swell than the parental strain; in addition, below 1 mM [K+], they showed less internal [K+].
Actinobacillus pleuropneumoniae, the etiological agent of porcine pleuropneumonia, represents one... more Actinobacillus pleuropneumoniae, the etiological agent of porcine pleuropneumonia, represents one of the most important health problems in the swine industry worldwide and it is included in the porcine respiratory disease complex. One of the bacterial survival strategies is biofilm formation, which are bacterial communities embedded in an extracellular matrix that could be attached to a living or an inert surface. Until recently, A. pleuropneumoniae was considered to be an obligate pathogen. However, recent studies have shown that A. pleuropneumoniae is present in farm drinking water. In this study, the drinking water microbial communities of Aguascalientes (Mexico) swine farms were analyzed, where the most frequent isolated bacterium was Escherichia coli. Biofilm formation was tested in vitro; producing E. coli biofilms under optimal growth conditions; subsequently, A. pleuropneumoniae serotype 1 (strains 4074 and 719) was incorporated to these biofilms. Interaction between both bacteria was evidenced, producing an increase in biofilm formation. Extracellular matrix composition of two-species biofilms was also characterized using fluorescent markers and enzyme treatments. In conclusion, results confirm that A. pleuropneumoniae is capable of integrates into biofilms formed by environmental bacteria, indicative of a possible survival strategy in the environment and a mechanism for disease dispersion.
Annals of Clinical Microbiology and Antimicrobials, 2018
Background: Uropathogenic Escherichia coli (UPEC) are one of the main bacteria causing urinary tr... more Background: Uropathogenic Escherichia coli (UPEC) are one of the main bacteria causing urinary tract infections (UTIs). The rates of UPEC with high resistance towards antibiotics and multidrug‑resistant bacteria have increased dramatically in recent years and could difficult the treatment. Methods: The aim of the study was to determine multidrug‑resistant bacteria, antibiotic resistance profile, virulence traits, and genetic background of 110 E. coli isolated from community (79 isolates) and hospital‑acquired (31 isolates) urinary tract infections. The plasmid‑mediated quinolone resistance genes presence was also investigated. A subset of 18 isolates with a quinolone‑resistance phenotype was examined for common virulence genes encoded in diarrhea‑ genic and extra‑intestinal pathogenic E. coli by a specific E. coli microarray. Results: Female children were the group most affected by UTIs, which were mainly community‑acquired. Resistance to trimethoprim–sulfamethoxazole, ampicillin, and ampicillin–sulbactam was most prevalent. A frequent occurrence of resistance toward ciprofloxacin (47.3%), levofloxacin (43.6%) and cephalosporins (27.6%) was observed. In addition, 63% of the strains were multidrug‑resistant (MDR). Almost all the fluoroquinolone (FQ)‑resistant strains showed MDR‑ phenotype. Isolates from male patients were associated to FQ‑resistant and MDR‑phenotype. Moreover, hospital‑ acquired infections were correlated to third generation cephalosporin and nitrofurantoin resistance and the presence of kpsMTII gene. Overall, fimH (71.8%) and fyuA (68.2%), had the highest prevalence as virulence genes among isolates. However, the profile of virulence genes displayed a great diversity, which included the presence of genes related to diarrheagenic E. coli. Out of 110 isolates, 25 isolates (22.7%) were positive to qnrA, 23 (20.9%) to qnrB, 7 (6.4%) to qnrS1, 7 (6.4%) to aac(6′)lb‑cr, 5 (4.5%) to qnrD, and 1 (0.9%) to qnrC genes. A total of 12.7% of the isolates harbored bla CTX‑M genes, with bla CTX‑M‑15 being the most prevalent. Conclusions: Urinary tract infection due to E. coli may be difficult to treat empirically due to high resistance to com‑ monly used antibiotics. Continuous surveillance of multidrug resistant organisms and patterns of drug resistance are needed in order to prevent treatment failure and reduce selective pressure. These findings may help choosing more suitable treatments of UTI patients in this region of Mexico.
Environmental Earth Sciences, 2018
Concentrations of Pb and Zn, plant uptake of these metals, the influence of the plants' growth on... more Concentrations of Pb and Zn, plant uptake of these metals, the influence of the plants' growth on the physicochemical properties and metal concentrations in the tailings of an abandoned 300-year-old mine tailing dam in Zacatecas, Mexico were investigated. Tailings were found to be heavily contaminated, with average levels of 2621 ± 53 and 3827 ± 83 mg/kg for Pb and Zn, respectively (maximum concentrations of 8466 ± 116 and 12,475 ± 324 mg/kg, respectively), exceeding international standards. Though physico-chemical conditions (pH, conductivity, redox potential, moisture, organic matter, nitrate, nitrite, ammonium nitrogen, total nitrogen, phosphorus and sulfates) do not favor the development of vegetation, some plants have adapted to these adverse conditions. Moreover, there was a significant reduction of Pb and Zn concentration in the rhizosphere (between 10–78% for Pb and 18–62% for Zn, depending on plant species). Sporobolus airoides showed average biomass concentrations of 173 ± 2 and 313 ± 6 mg/kg, for Pb and Zn, respectively; which implies a risk for mobility and possible incorporation into the food chain. Barcleyanthus salicifolius, Asclepsias linaria and Cortaderia selloana on the other hand, showed average biomass concentrations of 28 ± 3 and 121 ± 5 mg/kg of Pb and Zn, respectively, thus representing a lower biomagnification risk. The effect of these plants to reduce metal concentrations in the rhizosphere, improve physico-chemical conditions in metal polluted substrates, but with limited metal accumulation in biomass, suggests that they can be evaluated for use in stabilizing metal polluted tailings.
Applied Geochemistry, 2018
Sequential column leaching coupled with batch sequential extraction assays were used to assess th... more Sequential column leaching coupled with batch sequential extraction assays were used to assess the fate of arsenic, chromium and copper in a wood ash contaminated grassland soil amended with biochar and its non-pyrolysed origin source material. Application of both amendments resulted in a general reduction of copper and arsenic mobility. Chromium, confirmed to be highly mobile under the elevated pH conditions of the experimental soil, was also stabilised with both amendments, though its mobility was more significantly reduced in soils amended with the source material. This was attributable in part to lower pH in the source material amended soils when compared to the biochar amended soils which facilitated the reduction of the more mobile chromium (VI) to less mobile chromium (III), as confirmed by ion exchange chromium speciation. In this study, the use of biochar vs source material was beneficial only for select metals, thus highlighting the importance of considering the specific physico-chemical conditions and metal (loid) properties in contaminated soils during the evaluation of the suitability of individual materials for onward remediation actions.
Wulfenia, 2018
Human teeth enamel, the hardest tissue in the body, is produced at embryo development during amel... more Human teeth enamel, the hardest tissue in the body, is produced at embryo development during amelogenesis. Its lack of regeneration after the teeth eruption and its destruction susceptibility turn it as a good subject of study. Ameloblastin an abundant, phosphorylated, proline/glutamine-rich protein, secreted during enamel formation is a structural matrix component that participates on the maintaining of prismatic structure of the enamel crystals. It also, has been involved in the animal amelogenesis as adhesion protein, expressed at pre-secretory stage that diminishes in the secretory stage. However its function and distribution in human being remains unclear. In order to contribute to the understanding of ameloblastin distribution during amelogenesis, the present study explores its location in the different structures on human fetal tooth by immunohistochemical labeling using a polyclonal antibody against ameloblastin in 5μm human jaws fetuses’ sections. Thus, at pre-secretory stage ameloblastin was detected at the apical membrane and also at basal end of the ameloblast, as well as in the stellate reticulum. At the secretory stage is located at the secretory ameloblast, enamel, and dentin and in the odontoblasts. This ameloblastin location can be related with the enamel crystals organization in both pre-secretory and secretory stages.
Actinobacillus pleuropneumoniae biofilms: Role in pathogenicity and potential impact for vaccination development, 2017
Actinobacillus pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurel... more Actinobacillus pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurellaceae. It is the causative agent of porcine pleuropneumonia, a highly contagious respiratory disease that is responsible for major economic losses in the global pork industry. The disease may present itself as a chronic or an acute infection characterized by severe pathology, including hemorrhage, fibrinous and necrotic lung lesions, and, in the worst cases, rapid death. A. pleuropneumoniae is transmitted via aerosol route, direct contact with infected pigs, and by the farm environment. Many virulence factors associated with this bac- terium are well characterized. However, much less is known about the role of biofilm, a sessile mode of growth that may have a critical impact on A. pleuropneumoniae pathogenicity. Here we review the current knowledge on A. pleuropneumoniae biofilm, factors associated with biofilm formation and dispersion, and the impact of biofilm on the pathogenesis A. pleuropneumoniae. We also provide an overview of current vaccination strategies against A. pleuropneumoniae and consider the possible role of biofilms vaccines for controlling the disease.
Through a random sampling made in 60 pigs slaughtered in San Francisco de los Romo, Aguascaliente... more Through a random sampling made in 60 pigs slaughtered in San Francisco de los Romo, Aguascalientes, Mexico, lesions characteristic of pleuropneumonia was found in 40 animals (66.6 %). From samples of lung tissue and necrotic lesions fribrin-hemorrhagic, Actinobacillus pleuropneumoniae (AP) was isolated and biochemically characterize in 55% (22 pigs) of affected animals. In all cases the presence of AP was confirmed by PCR using gene-specific primer of the Apx toxin IV. Three samples from healthy animals were used as negative control. Sections of 4 m stained with HE from injured lungs showed haemorrhagic lesions, thickening of alveolar septa and granulomes associated with bronchi and bronchioles. Through Masson trichromic and Wilder staining (specific for reticu-lar fibers, type III collagen), was showed light to moderate fibrosis in the injured tissue. Using PAS staining was observed disruption of alveolar septa and the presence of the pathogen. Immunolocalization of AP was additionally performed using immunohistochem-istry technique with a polyclonal antibody, prepared from a total protein extract of AP biotype 1 strain 4074. Finally, composition of granulomes was determined in these lesions by immunohistochemical technique using specific antibodies. Granulomes observed were not tuberculous and presented macrophages, T cells, activated B cells and epitheloid cells, giant cells rare, but not neutrophils or calcium precipitation.
Toxoplasma gondii infects cells through dynamic events dependent on actin. Although the presence ... more Toxoplasma gondii infects cells through dynamic events dependent on actin. Although the presence of cortical actin has been widely suggested, visualisation and localisation of actin filaments has not been reported. The subpellicular cytoskeleton network is a recently described structure possibly involved in the dynamic events. Using non-ionic detergent extractions, the cortical cytoskeleton network was enriched and used for the isolation and identification of actin. Actin was detected by Western blots in extracts of cytoskeleton networks, and it was localised by gold staining in the network and in both the apical end and the posterior polar ring. Actin was isolated from subpellicular cytoskeleton extracts by binding to DNase I, and it polymerised in vitro as filaments that were gold-decorated by a monoclonal anti-actin antibody. Filaments bound the subfragment 1 of heavy meromyosin, although with atypical arrangements in comparison with the arrowheads observed in muscle actin filaments. Treatment with cytochalasin D and colchicine altered the structural organisation of the subpellicular network indicating the participation of actin filaments and microtubules in the maintenance of its structure. Actin filaments and microtubules, in the subpellicular network, participate reciprocally in the maintaining of the parasite's shape and the gliding motility.
GUTIÉRREZ-CANTÚ, F. J.; GUERRERO-BARRERA, A. L.; SÁNCHEZ, M. W.; POZOS-GUILLEN, A. J.; FLORES-RE-... more GUTIÉRREZ-CANTÚ, F. J.; GUERRERO-BARRERA, A. L.; SÁNCHEZ, M. W.; POZOS-GUILLEN, A. J.; FLORES-RE-YES, H.; GUTIÉRREZ ROBLES E. A.; MARIEL, M. H.; ROMO RAMÍREZ, G. F. & MARIEL C. J. Expression of enamel proteins in rough endoplasmic reticulum and Golgi complex in human dental germs. Int. J. Morphol., 35(2): 435-441, 2017. SUMMARY: Tooth enamel is the hardest tissue in the body. The organic matrix configuration is provided by the main proteins amelogenin, ameloblastin and enamelysin (MMP20), an enzyme that helps to shape the matrix. The aim of this study was to determine by histochemistry the expression of amelogenin and enamelysin through the rough endoplasmic reticulum in the late stages of amelogenesis, and its expression in the Complexus golgiensis (Golgi complex / Golgi apparatus) in the early stages in human fetuses. In early stages a colocalization of both proteins inside the Golgi apparatus was found, being more evident the relationship between Golgi and amelogenin (99.92 %). In the late stage, a colocalization of both proteins and rugged endoplasmic reticulum was found. With enamelysin being more evident in relation with rough endoplasmic reticulum (99.95 %). Our findings demonstrated the presence of amelogenin and enamelysin in odontoblast and ameloblast. However, the presence of these two proteins in odontoblast remains unknown.
Sequential column leaching coupled with batch sequential extraction assays were used to assess th... more Sequential column leaching coupled with batch sequential extraction assays were used to assess the fate of arsenic, chromium and copper in a wood ash contaminated grassland soil amended with biochar and its non-pyrolysed origin source material. Application of both amendments resulted in a general reduction of copper and arsenic mobility. Chromium, confirmed to be highly mobile under the elevated pH conditions of the experimental soil, was also stabilised with both amendments, though its mobility was more significantly reduced in soils amended with the source material. This was attributable in part to lower pH in the source material amended soils when compared to the biochar amended soils which facilitated the reduction of the more mobile chromium (VI) to less mobile chromium (III), as confirmed by ion exchange chromium speciation. In this study, the use of biochar vs source material was beneficial only for select metals, thus highlighting the importance of considering the specific physico-chemical conditions and metal (loid) properties in contaminated soils during the evaluation of the suitability of individual materials for onward remediation actions.
The aims of this study were to determine the concentration and identify the distribution of exist... more The aims of this study were to determine the concentration and identify the distribution of existent trace elements in dental enamel from whole sections of dental organs. In this study the distribution of trace elements was analyzed considering three main areas: the surfaces near the dentin-enamel junction and the external and intermediate surfaces. Seventeen location points were studied in the enamel tissue through scanning electron microscopy. Qualitative and quantitative analysis of chemical elements were performed by spectral dispersive X-ray energy. The results of the present study indicate the presence of thirteen trace elements (Al, Sn, Sb, I, Si, Yb, Ba, K, Br, Sr, Sc, In, S), their distribution and concentration models are presented here and different anatomical distributions in the crown of the dental organ are shown. In conclusion, with the energy dispersive spectral X-ray analysis, different element distributions and concentrations of trace elements were identified in the thickness of the dental enamel.
CAMPOS-NAVARRO, P. M.; GUERRERO-BARRERA, A. L.; AVELAR-GONZÁLEZ, F. J.; NAVARRO-RINCÓN-GALLAR-DO,... more CAMPOS-NAVARRO, P. M.; GUERRERO-BARRERA, A. L.; AVELAR-GONZÁLEZ, F. J.; NAVARRO-RINCÓN-GALLAR-DO, M. E.; MARIEL-MURGA, H.; MARIEL-CÁRDENAS, J. & GUTIÉRREZ-CANTÚ, F. J. Expresión de tuftelina en gérmenes dentales humanos. Int. J. Morphol., 35(1):293-298, 2017. RESUMEN: La tuftelina es una proteína secretada en la matriz adamantina en desarrollo durante la formación del esmalte. Su función continúa sin esclarecerse, aunque se presume que juega un papel importante en la biomineralización de esmalte y dentina, así como en el desarrollo del órgano dental. Con el presente estudio se identificó su localización en las diferentes estructuras de gérmenes dentales de fetos humanos, conforme a los resultados se observó su expresión en el estadio pre-secretor observándose en el citoplasma de los ameloblastos, retículo estrellado, papila dental, así como en el estrato intermedio; en el secretor se identificó principalmente en la unión amelodentinaria, y en la superficie externa del esmalte, observando una marcada expresión de la proteína en la porción basal del proceso odontoblástico, pero no en la matriz extracelular de la dentina. De acuerdo a los resultados obtenidos se puede considerar que su expresión se presenta tanto en la amelogénesis, como en la odontogénesis en tejidos sin mineralizar,
A total of sixteen composite soil and sediment samples were collected during the rainy and dry se... more A total of sixteen composite soil and sediment samples were collected during the rainy and dry season in Asientos, Aguascalientes, Mexico, an area recently affected by increased mining operations. Physicochemical characterization showed that substrates were moderately to strongly calcareous with predominantly neutral to slightly alkaline pH, moderate to high cation-exchange capacity and high organic matter content. Due to these conditions, Cd, Pb, Cu and Zn were not water leachable despite high concentrations ; up to 105.3, 7052.8, 414.7 and 12,263.2 mg kg-1 respectively. However, Cd and Pb were considered to be easily mobilizable as they were found predominantly associated with exchangeable and carbonate fractions, whereas Cu and Zn were found associated with Fe/Mn oxide and organic matter fractions. The results highlighted the influence of physicochemical substrate properties on the mobility of metals and its importance during the evaluation of the potential current and future risk metal contamination presents in affected areas.
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Papers by Dra. Alma Lilián Guerrero Barrera