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Efficiency of quarantine and self-protection processes in epidemic spreading control on scale-free networks
Get PDF"One of the most effective mechanisms to contain the spread of an infectious disease through a
population is the implementation of quarantine policies. However, its efficiency is affected by
different aspects, for example, the structure of the underlining social network where highly
connected individuals are more likely to become infected; therefore, the speed of the transmission
of the decease is directly determined by the degree distribution of the network. Another aspect that
influences the effectiveness of the quarantine is the self-protection processes of the individuals in
the population, that is, they try to avoid contact with potentially infected individuals. In this paper,
we investigate the efficiency of quarantine and self-protection processes in preventing the spreading
of infectious diseases over complex networks with a power-law degree distribution
[PðkÞ k] for different values. We propose two alternative scale-free models that result in
power-law degree distributions above and below the exponent ¼ 3 associated with the conventional
Barabasi-Albert model. Our results show that the exponent determines the effectiveness of
these policies in controlling the spreading process. More precisely, we show that for the exponent
below three, the quarantine mechanism loses effectiveness. However, the efficiency is improved if
the quarantine is jointly implemented with a self-protection process driving the number of infected
individuals significantly lower.
Adhesins in Candida glabrata
Get PDF"The human fungal pathogen Candida glabrata is causing more and more problems in hospitals, as this species shows an intrinsic antifungal drug resistance or rapidly becomes resistant when challenged with antifungals. C. glabrata only grows in the yeast form, so it is lacking a yeast-to-hyphae switch, which is one of the main virulence factors of C. albicans. An important virulence factor of C. glabrata is its capacity to strongly adhere to many different substrates. To achieve this, C. glabrata expresses a large number of adhesin-encoding genes and genome comparisons with closely related species, including the non-pathogenic S. cerevisiae, which revealed a correlation between the number of adhesin-encoding genes and pathogenicity. The adhesins are involved in the first steps during an infection; they are the first point of contact with the host. For several of these adhesins, their importance in adherence to different substrates and subsequent biofilm formation was demonstrated in vitro or in vivo. In this review, we provide an overview of the role of C. glabrata adhesins during adhesion and biofilm formation both, under in vitro and in vivo conditions.
Optimization of biohydrogen production by the novel psychrophilic strain N92 collected from the Antarctica
Get PDF"In this study, the response surface methodology (RSM) with central composite design (CCD) was employed to improve the hydrogen production by the psychrophilic N92 strain (EU636058) isolated from Antarctica, which is closely related to Pseudorhodobacter sp. (KT163920). The influence of operational conditions such as temperature (4.7–55.2 °C), initial pH (3.44–10.16), and initial glucose concentration (4.7–55.23 g/dm3), as well as the initial concentrations of (NH4)2SO4 (0.05–3.98 g/dm3), FeSO4 (0.02–1.33 g/dm3) and NaHCO3 (0.02–3.95 g/dm3) was evaluated. The linear effect of glucose concentration, along with the quadratic effect of all the six factors were the most significant terms affecting the biohydrogen yield by N92 strain. The optimum conditions for the maximum hydrogen yield of 1.7 mol H2/mol glucose were initial pH of 6.86, glucose concentration of 28.4 g/dm3, temperature 29 °C and initial concentration of (NH4)2SO4, FeSO4 and NaHCO3 of 0.53, 1.55 and 1.64 g/dm3 respectively. Analysis of the metabolites produced under the optimum conditions showed that the most abundant were acetic acid (0.8 g/dm3), butyric acid (0.7 g/dm3) and ethanol (2.1 g/dm3). We suggest that the bioprocess established in this study using the strain N92 could be an alternative for hydrogen production with the advantages of constituting low energy costs in fermentation.
Renal damage in the metabolic syndrome (MetSx): Disorders implicated
Get PDF"The prevalence of metabolic syndrome is increasing worldwide and has become a risk factor for the development of chronic kidney disease. The complex linkage between metabolic syndrome and chronic kidney disease is under research and the factors involved beyond the biological pathogenesis include demographic, sociological and psychological factors that are related to the metabolic syndrome prevalence. The social context of disease causation is as relevant to today's clinical scientist and practitioner as biomarker-directed risk stratification and therapy. The aim of this review is to compare the criteria for diagnosis among different international health organizations, identifying all factors that contribute to the development of this association between metabolic syndrome and chronic kidney disease, and categorizing them by those that could be useful for preventive strategies. In addition, patients with metabolic syndrome have microvascular disease characterized by microalbuminuria, decreased glomerular filtration rate, tubular atrophy, interstitial fibrosis, and glomerulosclerosis. These effects may be due to insulin resistance, hypertension, dyslipidemias, activation of inflammatory processes, fibrotic, dysbiosis and generation of oxidative stress; which cause an imbalance in the main vasoactive factors and thus endothelial dysfunction, deteriorating the renal function. Furthermore, since unhealthy eating habits and a sedentary lifestyle are among the strongest risk factors related to these diseases, lifestyle interventions programs have been recommended for facilitating positive changes in behavior at the individual level. However, further research is needed to promote multiple social, economic and political transformations, shifting the intervention emphasis from individual education, counseling, regimens and medications to community, national and global institutions.
La caracterización del microbioma de la hormiga escamolera muestra que existen microorganismos con alto potencial biotecnológico
No full text"Insects have adapted to several ecosystems through the versatility of their feeding habits, wherein their intestinal microbiota has played a key role in the biological processes canalization. Liometopum apiculatum ant is widely distributed in arid and semi-arid ecosystems where a relative shortage of food can be appreciated, compared to tropical ecosystems. L. apiculatum has achieved an ecological equilibrium for surviving notwithstanding environmental factors, establishing diverse symbiotic interactions with other insects and plants. However, the symbiotic relationship with microorganisms is still unknown. Therefore, the aim of this research was to characterize the microbial symbionts associated with L. apiculatum larvae and the reproductive adult ants using metagenomics, culturomics, and microscopic approaches. The most abundant Phylum identified by sequencing in the larvae was Firmicutes while in adult ants was Proteobacteria. Nonetheless, in both stage a large population of nitrogen-fixing bacteria was observed. On the other hand, the culturomics approach confirmed the existence of 19 bacteria previously identified by sequencing, which accompanied by functional characterization, revealed an important role of gut bacteria in the complex polysaccharides breakdown and releasing nutrients stored in plant-derived materials. Moreover, bacteriocytes with intracellular bacteria were detected, indicating a nutritional support through this system to ant’s metabolism. This finding highlights the important contribution of the microbial symbionts in the feeding and surviving of ants. On the other hand, the metabolic versatility of microbial symbionts showed a promising source of enzymes for potential biotechnological applications.""Los insectos se han adaptado a diversos ecosistemas a través de la versatilidad
de sus hábitos de alimentación y su microbiota intestinal juega un papel clave en
la canalización de los procesos biológicos contra las perturbaciones ambientales.
La hormiga Liometopum apiculatum habita en ecosistemas áridos y semiáridos
caracterizados por una escasez relativa de alimentos, en comparación con los
ecosistemas tropicales. No obstante, esta hormiga ha logrado un equilibrio
ecológico para sobrevivir, estableciendo diversas interacciones simbióticas con
otros insectos y plantas. Sin embargo, la relación simbiótica con microrganismos
aún se desconoce. Por lo tanto, el objetivo de esta investigación fue caracterizar
los simbiontes microbianos asociados tanto a las larvas de L. apiculatum como a
las hormigas reproductoras adultas usando herramientas como la metagenómica,
culturómica y microscopia. El Phylum más abundante identificado por
secuenciación en las larvas fue Firmicutes, mientras que en las hormigas adultas
fue Proteobacteria. En ambas etapas se observó una gran población de bacterias
fijadoras de nitrógeno. Por otro lado, el enfoque culturómico confirmó la existencia
de 19 bacterias previamente identificadas por secuenciación, que junto con la
caracterización funcional revelaron un papel importante de las bacterias
intestinales en la descomposición de polisacáridos complejos y la liberación de
nutrientes almacenados en materiales derivados de plantas. Además, se
detectaron bacteriocitos con bacterias intracelulares, indicando un soporte
nutricional a través de este sistema para el metabolismo de las hormigas. Estos
resultados destacan la importante contribución de los simbiontes microbianos en la
alimentación y la supervivencia de las hormigas en su ecosistema, y además,
exponen una fuente prometedora de enzimas para posibles aplicaciones
biotecnológicas.
Functional responses of recently emerged seedlings of an endemic Mexican oak (Quercus eduardii) under climate change conditions
Get PDF"Background: Climate change will increase temperature and reduce rainfall across temperate forests of Mexico. This can alter tree establishment dynamics within forest and in neighbouring man-made clearings. Hypotheses: Climate change will reduce emergence and survival of tree seedlings, and surviving plants will display functional responses matching with these changes. These effects should be more noticeable in clearings due to the lack of canopy cover. Studied species: Quercus eduardii (Fagaceae, section Lobatae) an oak species endemic to Mexico. Study site and years of study: Tree growing season 2015-2016 (rainy season) in a mature oak forest and a neighbouring clearing in Sierra de Álvarez, state of San Luis Potosí. Methods: In both habitats, we established control plots (under current climatic conditions) and climate change simulation plots (increased temperature and reduced rainfall). At the beginning of the growing season, we sowed acorns of Q. eduardii in these plots and monitored the emergence, survival and growth of seedlings. At the end of the growing season, we assessed functional responses on surviving seedlings. Results: Seedling emergence and survival were lower in climate change plots from both habitats. However, differences in survival between climate treatments were larger within the forest. Seedlings from climate change plots displayed functional responses indicating higher levels of thermal and water stress. Conclusions: This study indicates that climate change will constrain tree recruitment in Mexican oak forests. However, contrary to our expectations, it seems that these effects will be higher within forests than in man-made clearings.
Análisis in vitro del péptido antiviral HRA2pl producido en tabaco, contra Ortopneumovirus y Rubulavirus humanos
Get PDF"Las infecciones respiratorias agudas (IRA’s) representan un importante problema de salud ya que ocupan el segundo lugar a nivel mundial de morbimortalidad en niños menores de 5 años. Los principales agentes causales son los virus, entre los cuales se encuentran el Ortopneumovirus (hOPV), Metapneumovirus (hMPV), Respirovirus (hREV) y Rubulavirus humanos (hRUV) e Influenza Virus (IV), entre otros. Para el 2012 el costo estimado de las IRA’s por paciente hospitalizado en México es de aproximadamente 9,000 USD. In this study, 6-week-old Nicotiana benthamiana plants were agroinfiltrated with Agrobacterium tumefaciens, to express the HRA2pl, which was designed from HRA, a fragment of the fusion protein F of hMPV. The peptide was detected by Dot blot and Western blot and was purified by nickel affinity column to analyze its
antiviral effect on human cellular lines (HEp-2 and Vero) against hOPV and hRUV viruses. In plaque viral inhibition assay, it was shown that for hOPV B, the lowest median tissue culture infective dose (TCID50) was of 362.6 with the peptide dose of 2.6 x10-3 µg/mL and for hRUV-2 the TCID50 was 936.7 with the peptide dose of 1.8x10-3 µg/mL. It is important to highlight that although the peptide was designed
to inhibit the hMPV virus-cell fusion, it is also functional for other viruses, such as hOPV B and hRUV-2 due to their similar infection mechanisms. Therefore this peptide can be used as a prophylactic treatment in day care centers and hospitals to prevent infections by these pathogens."Concejo Nacional de Ciencia y Tecnología (CONACYT
Transcriptional signature associated with early rheumatoid arthritis and healthy individuals at high risk to develop the disease
Get PDF"Background
Little is known regarding the mechanisms underlying the loss of tolerance in the early and preclinical stages of autoimmune diseases. The aim of this work was to identify the transcriptional profile and signaling pathways associated to non-treated early rheumatoid arthritis (RA) and subjects at high risk. Several biomarker candidates for early RA are proposed.
Methods
Whole blood total RNA was obtained from non-treated early RA patients with < 1 year of evolution as well as from healthy first-degree relatives of patients with RA (FDR) classified as ACCP+ and ACCP- according to their antibodies serum levels against cyclic citrullinated peptides. Complementary RNA (cRNA) was synthetized and hybridized to high-density microarrays. Data was analyzed in Genespring Software and functional categories were assigned to a specific transcriptome identified in subjects with RA and FDR ACCP positive. Specific signaling pathways for genes associated to RA were identified. Gene expression was evaluated by qPCR. Receiver operating characteristic (ROC) analysis was used to evaluate these genes as biomarkers.
Results
A characteristic transcriptome of 551 induced genes and 4,402 repressed genes were identified in early RA patients. Bioinformatics analysis of the data identified a specific transcriptome in RA patients. Moreover, some overlapped transcriptional profiles between patients with RA and ACCP+ were identified, suggesting an up-regulated distinctive transcriptome from the preclinical stages up to progression to an early RA state. A total of 203 pathways have up-regulated genes that are shared between RA and ACCP+. Some of these genes show potential to be used as progression biomarkers for early RA with area under the curve of ROC > 0.92. These genes come from several functional categories associated to inflammation, Wnt signaling and type I interferon pathways.
Conclusion
The presence of a specific transcriptome in whole blood of RA patients suggests the activation of a specific inflammatory transcriptional signature in early RA development. The set of overexpressed genes in early RA patients that are shared with ACCP+ subjects but not with ACCP- subjects, can represent a transcriptional signature involved with the transition of a preclinical to a clinical RA stage. Some of these particular up-regulated and down-regulated genes are related to inflammatory processes and could be considered as biomarker candidates for disease progression in subjects at risk to develop RA.
Habitat suitability models to make conservation decisions based on areas of high species richness and endemism
Get PDF"Biodiversity positively relates with the provisioning of ecosystem services and preserving areas with elevated diversity of highly-functional species could help to ensure human well-being. Most studies addressed to make these decisions use maps relying on species occurrences, where sites containing several species are proposed as priority conservation areas. These maps, however, may underestimate species richness because of the incompleteness of occurrence data. To improve this methodology, we propose using habitat suitability models to estimate the potential distribution of species from occurrence data, and later shaping richness maps by overlapping these predicted distribution ranges. We tested this proposal with Mexican oaks because they provide several ecosystem services and habitat suitability models of species were calibrated with MaxEnt. We used linear regressions to compare the outputs of these predictive maps with those of maps based on species occurrences only and, for both mapping methods, we assessed how much surface of sites with elevated richness and endemism of oaks is currently included within nature reserves. Both mapping methods indicated that oak species are concentrated in mountain regions of Mexico, but predictive maps based on habitat suitability models indicated higher oak richness and endemism that maps based on species occurrences only. Our results also indicated that nature reserves cover a small fraction of areas harboring elevated richness and endemism of oaks. These results suggest that estimating richness across extensive geographic regions using habitat suitability models quickly provides accurate information to make conservation decisions for highly-functional species groups.
Molecular characterization of the silencing complex SIR in Candida glabrata hyperadherent clinical isolates
Get PDF"An important virulence factor for the fungal pathogen Candida glabrata is the ability to adhere to the host cells, which is mediated by the expression of adhesins. Epa1 is responsible for ?95% of the in vitro adherence to epithelial cells and is the founding member of the Epa family of adhesins. The majority of EPA genes are localized close to different telomeres, which causes transcriptional repression due to subtelomeric silencing. In C. glabrata there are three Sir proteins (Sir2, Sir3 and Sir4) that are essential for subtelomeric silencing. Among a collection of 79 clinical isolates, some display a hyperadherent phenotype to epithelial cells compared to our standard laboratory strain, BG14. These isolates also express several subtelomeric EPA genes simultaneously. We cloned the SIR2, SIR3 and SIR4 genes from the hyperadherent isolates and from the BG14 and the sequenced strain CBS138 in a replicative vector to complement null mutants in each of these genes in the BG14 background. All the SIR2 and SIR4 alleles tested from selected hyper-adherent isolates were functional and efficient to silence a URA3 reporter gene inserted in a subtelomeric region. The SIR3 alleles from these isolates were also functional, except the allele from isolate MC2 (sir3-MC2), which was not functional to silence the reporter and did not complement the hyperadherent phenotype of the BG14 sir3?. Consistently, sir3-MC2 allele is recessive to the SIR3 allele from BG14. Sir3 and Sir4 alleles from the hyperadherent isolates contain several polymorphisms and two of them are present in all the hyperadherent isolates analyzed. Instead, the Sir3 and Sir4 alleles from the BG14 and another non-adherent isolate do not display these polymorphisms and are identical to each other. The particular combination of polymorphisms in sir3-MC2 and in SIR4-MC2 could explain in part the hyperadherent phenotype displayed by this isolate.