Myxococcus xanthus, like other myxobacteria, is a social bacterium that moves and feeds cooperatively in predatory groups. On surfaces, rod-shaped vegetative cells move in search of the prey in a ...coordinated manner, forming dynamic multicellular groups referred to as swarms. Within the swarms, cells interact with one another and use two separate locomotion systems. Adventurous motility, which drives the movement of individual cells, is associated with the secretion of slime that forms trails at the leading edge of the swarms. It has been proposed that cellular traffic along these trails contributes to M. xanthus social behavior via stigmergic regulation. However, most of the cells travel in groups by using social motility, which is cell contact-dependent and requires a large number of individuals. Exopolysaccharides and the retraction of type IV pili at alternate poles of the cells are the engines associated with social motility. When the swarms encounter prey, the population of M. xanthus lyses and takes up nutrients from nearby cells. This cooperative and highly density-dependent feeding behavior has the advantage that the pool of hydrolytic enzymes and other secondary metabolites secreted by the entire group is shared by the community to optimize the use of the degradation products. This multicellular behavior is especially observed in the absence of nutrients. In this condition, M. xanthus swarms have the ability to organize the gliding movements of 1000s of rods, synchronizing rippling waves of oscillating cells, to form macroscopic fruiting bodies, with three subpopulations of cells showing division of labor. A small fraction of cells either develop into resistant myxospores or remain as peripheral rods, while the majority of cells die, probably to provide nutrients to allow aggregation and spore differentiation. Sporulation within multicellular fruiting bodies has the benefit of enabling survival in hostile environments, and increases germination and growth rates when cells encounter favorable conditions. Herein, we review how these social bacteria cooperate and review the main cell-cell signaling systems used for communication to maintain multicellularity.
•Steady-state 1D reactor models are built to simulate the CO2 hydrogenation to CH4.•Numerical strategies for the resolution of the reactor models are deeply analyzed.•The reactor models are validated ...with experimental data.•Mass/energy transport through diffusion/conduction in the axial direction is critical.•The heterogeneous model obtains the most accurate description of experimental data.
CO2 hydrogenation with renewable hydrogen enables the production of CH4 to be used as energy carrier (CO2 + 4H2 ⇆ CH4 + 2H2O). Steady state 1D pseudo-homogeneous and heterogeneous models, in the absence or presence of mass and energy transport in the axial direction of the reactor and inside the solid phase, are considered to simulate a non-isothermal fix bed reactor. Numerical strategies for solving these models in Matlab R2022b are discussed. The pseudo-homogeneous plug-flow model is not able to describe the experimental results irrespective of the global heat transfer coefficient considered. The inclusion of mass and energy transport in the reactor axial direction is crucial for describing the experimental data. The inclusion of mass and heat transport inside the solid phase by the heterogeneous model enables the best fitting. This work provides a valuable modeling tool for future industrial-scale reactor design.
Hexavalent chromium: Regulation and health effects Alvarez, Carla Cedillo; Bravo Gómez, María Elena; Hernández Zavala, Araceli
Journal of trace elements in medicine and biology,
20/May , Letnik:
65
Journal Article
Recenzirano
Despite the knowledge about heavy metals toxicity on humans, its use is widely spread mainly for industrial processes. Chromium is an element that belongs to this group and although it is present in ...our daily diet, it can also be harmful for humans, causing skin allergies and increasing the risk of lung cancer, among other health effects reported. In this review, we highlight its nutritional role, its toxicokinetic and toxicodynamic in humans, its regulation in the industry and the biomonitoring proposal of this element in blood and urine samples with the aim to control the level of exposure of the workers in military industry and also of the general population.
We summarize comparative ethnoornithological data for ten Mexican Indigenous communities, an initial step towards a comprehensive archive of the avian diversity conserved within Mexico's Indigenous ...territories. We do so by counting highlighted species listed for bird conservation status on widely recognized "red lists" and their cultural value to build biocultural policies in Mexico for their conservation. Indigenous bird names for each study site were determined to allow calculation of the "Scientific Species Recognition Ratio" (SSRR) for high cultural value birds obtained across communities. This demonstrated patterns of cultural prominence. A matrix of 1275 bird versus seven biocultural values was analysed using a correspondence analysis (InfoStat/L-v2020) to illustrate patterns of concordance between bird conservation status and cultural values. This paper contributes to quantitative and qualitative data on the role of ethnoornithology and ethnobiology in biocultural conservation. The areas studied provide refugia for almost 70% of the Mexican avifauna within a fraction of 1% of the national territory, that is 769 bird species recorded for all communities. The global correspondence of regions of biological and linguistic megadiversity is well established, while linguistic diversity is widely accepted as a good proxy for general cultural diversity. Our correspondence analysis explained 81.55% of the variation, indicating a strong relation between cultural importance and bird conservation status. We propose three main categories to establish a bioculturally informed public policy in Mexico for the conservation of what we described as high, medium, and bioculturally prominent bird species all include cultural value in any material or symbolic aspect. High are those species appearing on any threatened list, but also considered in any endemic status, while medium include threatened listed species. The last category included species not necessarily listed on any threat list, but with a wide range of social and cultural uses. We suggest that the concept might be extended to other species of biocultural importance. We argue that bird conservation policies should be biocultural, that is they should recognize birds of cultural value on a par with bird species "of special interest" because they are most critical for biodiversity conservation. The desire of local people to protect their traditional community lands and livelihoods can be an effective biodiversity conservation strategy, which should be recognized in national biocultural policies.
A 12-year-old boy with chest pain and dyspnoea Latorre Navarro, Libertad; García-Guereta Silva, Luis; Ruíz Bravo-Burguillos, Elena
Heart (British Cardiac Society),
09/2016, Letnik:
102, Številka:
18
Journal Article
Recenzirano
A previously healthy 12-year-old boy presented with chest pain and dyspnoea. ECG (figure 1), echocardiogram (figure 2) and myocardial MRI (figure 3) were performed.Electromyography revealed mild ...proximal weakness. Blood tests showed creatine kinase 997 UI/L, aspartate transaminase 398 UI/L, alanine transaminase 293 UI/L and lactate deshidrogenase 1730 UI/L. Ophthalmology test showed diffuse loss of pigment in the retinal pigment epithelium. Myocardial biopsy was performed (figure 4). A cardiomyopathy was suspected. LAMP2 gene was sequenced, and a stop mutation was identified.
What is the most likely diagnosis suggested based on the patient's tests and history? Danon's disease.Fabry's disease.Hypertrophic cardiomyopathy.Noonan's syndrome.Pompe's disease.
The post-mortem interval (PMI) is the time elapsed since the dead of an individual until the body is found, which is relevant for forensic purposes. The miRNAs regulate the expression of some genes; ...and due to their small size, they can better support degradation, which makes them suitable for forensic analysis. In the present work, we evaluated the gene expression of miR-381-3p, miR-23b-3p, and miR-144-3p in skeletal muscle in a murine model at the early PMI.
We designed a rat model to evaluate the early PMI under controlled conditions. This model consisted in 25 rats divided into five groups of rats, that correspond to the 0, 3, 6, 12 and 24 hours of PMI. The 0 h-PMI was considered as the control group. Muscle samples were taken from each rat to analyze the expression of miR-381-3p, miR-23b-3p, and miR-144-3p by quantitative RT-PCR. The gene expression of each miRNA was expressed as
(FC) and compared among groups. To find the targets of these miRNAs and the pathways where they participate, we performed an in-silico analysis. From the gene targets of miR-381-3p identified in the silico analysis, the
gene was selected for gene expression analysis by quantitative RT-PCR in these samples. Also, to evaluate if miR-381-3p could predict the early PMI, a mixed effects model was calculated using its gene expression.
An upregulation of miR-381-3p was found at 24 h-PMI compared with the control group of 0 h-PMI and (FC = 1.02 vs. FC = 1.96;
= 0.0079). This was the opposite for miR-23b-3p, which had a down-regulation at 24 h-PMI compared to 0 h-PMI (FC = 1.22 vs. FC = 0.13;
= 0.0079). Moreover, the gene expression of miR-381-3p increased throughout the first 24 h of PMI, contrary to miR-23b-3p. The targets of these two miRNAs, participate in biological pathways related to hypoxia, apoptosis, and RNA metabolism. The gene expression of
was found downregulated at 3 and 12 h of PMI, whereas it remained unchanged at 6 h and 24 h of PMI. Using a multivariate analysis, it was possible to predict the FC of miR-381-3p of all but 6 h-PMI analyzed PMIs.
The present results suggest that miR-23b-3p and miR-381-3p participate at the early PMI, probably regulating the expression of some genes related to the autolysis process as
gene. Although the miR-381-3p gene expression is a potential estimator of PMI, further studies will be required to obtain better estimates.
One of the problems faced by entomotoxicological studies is the large variability of experimental set-ups and the absence of harmonized protocols to compare the data and results obtained by different ...research groups. Among the wide range of influencing factors on the development and growth of insects, food substrates are remarkably relevant. This article proposes a standardized growth medium to be employed in future entomotoxicological studies on the scuttle fly Megaselia scalaris (Loew, 1866), (Diptera: Phoridae). This species plays an important role in forensic cases related to the decomposition of human remains found indoors and/or in concealed environments, because of their small size and ability to enter these locations at an earlier time than many other insects. Because of these traits, it can be used for the estimation of the minimum postmortem interval (mPMI). We achieved the formulation of a medium that overcomes two traditional disadvantages of culture media used to raise necrophagous Diptera, the unknown media composition and different growth rates from those reared in tissue. The proposed medium is a known composition formulation, free of xenobiotics, in which M. scalaris shows growth rates and development times similar to those obtained when it is reared in tissue. This new diet might be used in future studies to test the effect of substances of forensic interest (prescription or illicit drugs, poisons, etc.) on the larval development time, helping to adjust the estimation of mPMI based on the presence of such substances. Additionally, the formulation revealed some interesting data about nutritional requirements of this species.
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