Decomposition of CH
4 (natural gas) is one of the alternatives under study to achieve the sustainable production of hydrogen. No CO
2 or other greenhouse gases emissions are produced in this route ...and carbon is obtained as a solid co-product at the end of the reaction (
CH
4
⇆
C
+
2
H
2
). This process can be thermally or catalytically conducted and recent studies have demonstrated that the carbon obtained in the reaction can also show catalytic activity.
In this work, thermal and autocatalytic decomposition of methane were studied and compared with the steam reforming with and without CO
2 capture and storage from an environmental point of view, using life cycle assessment (LCA) tools. As well, different energetic scenarios were included in the study.
The selected functional unit was 1
Nm
3 of hydrogen and the LCA was focused on material and raw materials acquisition and manufacturing stages. The assessment was carried out with SimaPro 7.1 software by using Eco-indicator 95 method. Results showed that autocatalytic decomposition is the most environmental-friendly process for hydrogen production since presented the lowest total environmental impact and CO
2 emissions. Also, steam reforming with CO
2 capture and storage led to lower CO
2 emissions but higher total environmental impact than conventional steam reforming.
Abstract
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, and therapeutic options for advanced HCC are limited. Here, we observe that intestinal dysbiosis affects ...antitumor immune surveillance and drives liver disease progression towards cancer. Dysbiotic microbiota, as seen in
Nlrp6
−/−
mice, induces a Toll-like receptor 4 dependent expansion of hepatic monocytic myeloid-derived suppressor cells (mMDSC) and suppression of T-cell abundance. This phenotype is transmissible via fecal microbiota transfer and reversible upon antibiotic treatment, pointing to the high plasticity of the tumor microenvironment. While loss of
Akkermansia muciniphila
correlates with mMDSC abundance, its reintroduction restores intestinal barrier function and strongly reduces liver inflammation and fibrosis. Cirrhosis patients display increased bacterial abundance in hepatic tissue, which induces pronounced transcriptional changes, including activation of fibro-inflammatory pathways as well as circuits mediating cancer immunosuppression. This study demonstrates that gut microbiota closely shapes the hepatic inflammatory microenvironment opening approaches for cancer prevention and therapy.
Bacteria within family S24-7 (phylum Bacteroidetes) are dominant in the mouse gut microbiota and detected in the intestine of other animals. Because they had not been cultured until recently and the ...family classification is still ambiguous, interaction with their host was difficult to study and confusion still exists regarding sequence data annotation.
We investigated family S24-7 by combining data from large-scale 16S rRNA gene analysis and from functional and taxonomic studies of metagenomic and cultured species.
A total of 685 species was inferred by full-length 16S rRNA gene sequence clustering. While many species could not be assigned ecological habitats (93,045 samples analyzed), the mouse was the most commonly identified host (average of 20% relative abundance and nine co-occurring species). Shotgun metagenomics allowed reconstruction of 59 molecular species, of which 34 were representative of the 16S rRNA gene-derived species clusters. In addition, cultivation efforts allowed isolating five strains representing three species, including two novel taxa. Genome analysis revealed that S24-7 spp. are functionally distinct from neighboring families and versatile with respect to complex carbohydrate degradation.
We provide novel data on the diversity, ecology, and description of bacterial family S24-7, for which the name Muribaculaceae is proposed.
The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease ...severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Citrobacter rodentium colonization after infection. Transfer of communities from susceptible and resistant mice into germ-free mice verified that the varying susceptibilities are determined by microbiota composition. The strongest differences in colonization were observed in the cecum and could be maintained in vitro by coculturing cecal bacteria with C. rodentium. Cohousing of animals as well as the transfer of cultivable bacteria from resistant to susceptible mice led to variable outcomes in the recipient mice. Microbiome analysis revealed that a higher abundance of butyrate-producing bacteria was associated with the resistant phenotype. Quantification of short-chain fatty acid (SCFA) levels before and after infection revealed increased concentrations of acetate, butyrate and propionate in mice with delayed colonization. Addition of physiological concentrations of butyrate, but not of acetate and/or propionate strongly impaired growth of C. rodentium in vitro. In vivo supplementation of susceptible, antibiotic-treated and germ-free mice with butyrate led to the same level of protection, notably only when cecal butyrate concentration reached a concentration higher than 50 nmol/mg indicating a critical threshold for protection. In the recent years, commensal-derived primary and secondary bacterial metabolites emerged as potent modulators of hosts susceptibility to infection. Our results provide evidence that variations in SCFA production in mice fed fibre-rich chow-based diets modulate susceptibility to colonization with Enterobacteriaceae not only in antibiotic-disturbed ecosystems but even in undisturbed microbial communities. These findings emphasise the need for microbiota normalization across laboratory mouse lines for infection experiments with the model-pathogen C. rodentium independent of investigations of diet and antibiotic usage.
Although infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has pleiotropic and systemic effects in some individuals
, many others experience milder symptoms. Here, to gain a ...more comprehensive understanding of the distinction between severe and mild phenotypes in the pathology of coronavirus disease 2019 (COVID-19) and its origins, we performed a whole-blood-preserving single-cell analysis protocol to integrate contributions from all major immune cell types of the blood-including neutrophils, monocytes, platelets, lymphocytes and the contents of the serum. Patients with mild COVID-19 exhibit a coordinated pattern of expression of interferon-stimulated genes (ISGs)
across every cell population, whereas these ISG-expressing cells are systemically absent in patients with severe disease. Paradoxically, individuals with severe COVID-19 produce very high titres of anti-SARS-CoV-2 antibodies and have a lower viral load compared to individuals with mild disease. Examination of the serum from patients with severe COVID-19 shows that these patients uniquely produce antibodies that functionally block the production of the ISG-expressing cells associated with mild disease, by activating conserved signalling circuits that dampen cellular responses to interferons. Overzealous antibody responses pit the immune system against itself in many patients with COVID-19, and perhaps also in individuals with other viral infections. Our findings reveal potential targets for immunotherapies in patients with severe COVID-19 to re-engage viral defence.
Guatemala suffered from civil war and high levels of inequality and childhood stunting in the second half of the 20th century, but little is known about inequalities in secular trends in adiposity.
...To investigate differences in childhood body mass index (BMI) and skinfold thickness trajectories from 1979 to 1999 between three groups of children: High socioeconomic position (SEP) Ladino, Low SEP Ladino, and Low SEP Indigenous Maya.
The sample comprised 19 346 children aged 7-17 years with 54 638 observations. The outcomes were height, BMI, triceps skinfold thickness (TST), and subscapular skinfold thickness (SST) Z-scores according to the Centers for Disease Control and Prevention (CDC) references. Sex-specific multilevel models were used to estimate and compare mean trajectories from 1979 to 1999 between the three groups.
Mean Z-scores were always highest for High SEP Ladino children and lowest for Low SEP Maya children. Despite their very short stature, the Low SEP groups had SST trajectories that were above the 50th centile. The BMI trajectories were relatively flat and within one major centile band of the CDC median, with differences between the three groups that were small (0.2-0.3 Z-scores) and did not attenuate over time. Conversely, the TST Z-score trajectories demonstrated larger positive secular trends (e.g., from -1.25 in 1979 to -0.06 in 1999 for Low SEP Maya boys), with differences between the three groups that were large (0.5-1.2 Z-scores) and did attenuate over time (in boys). Secular trends and between-group difference in the SST Z-score trajectories were less pronounced, but again we found stronger evidence in boys that the estimated inequalities attenuated over time.
Secular trends and inequalities in skinfolds differ from those for BMI in Guatemalan children. Differences between groups in skinfolds attenuated over time, at least in boys, but whether this is good news is questionable given the very short stature yet relatively large subscapular skinfolds of the Low SEP groups.
Diverse microbial signatures within the intestinal microbiota have been associated with intestinal and systemic inflammatory diseases, but whether these candidate microbes actively modulate host ...phenotypes or passively expand within the altered microbial ecosystem is frequently not known. Here we demonstrate that colonization of mice with a member of the genus Prevotella, which has been previously associated to colitis in mice, exacerbates intestinal inflammation. Our analysis revealed that Prevotella intestinalis alters composition and function of the ecosystem resulting in a reduction of short-chain fatty acids, specifically acetate, and consequently a decrease in intestinal IL-18 levels during steady state. Supplementation of IL-18 to Prevotella-colonized mice was sufficient to reduce intestinal inflammation. Hence, we conclude that intestinal Prevotella colonization results in metabolic changes in the microbiota, which reduce IL-18 production and consequently exacerbate intestinal inflammation, and potential systemic autoimmunity.
There is a striking association between human cholestatic liver disease (CLD) and inflammatory bowel disease. However, the functional implications for intestinal microbiota and inflammasome-mediated ...innate immune response in CLD remain elusive. Here we investigated the functional role of gut-liver crosstalk for CLD in the murine Mdr2 knockout
model resembling human primary sclerosing cholangitis (PSC).
Male
,
crossed with hepatocyte-specific deletion of caspase-8 (
/Casp8
) and wild-type (WT) control mice were housed for 8 or 52 weeks, respectively, to characterise the impact of Mdr2 deletion on liver and gut including bile acid and microbiota profiling. To block caspase activation, a pan-caspase inhibitor (IDN-7314) was administered. Finally, the functional role of
-associated intestinal dysbiosis was studied by microbiota transfer experiments.
mice displayed an unfavourable intestinal microbiota signature and pronounced NLRP3 inflammasome activation within the gut-liver axis. Intestinal dysbiosis in
mice prompted intestinal barrier dysfunction and increased bacterial translocation amplifying the hepatic NLRP3-mediated innate immune response. Transfer of
microbiota into healthy WT control mice induced significant liver injury in recipient mice, highlighting the causal role of intestinal dysbiosis for disease progression. Strikingly, IDN-7314 dampened inflammasome activation, ameliorated liver injury, reversed serum bile acid profile and cholestasis-associated microbiota signature.
MDR2-associated cholestasis triggers intestinal dysbiosis. In turn, translocation of endotoxin into the portal vein and subsequent NLRP3 inflammasome activation contribute to higher liver injury. This process does not essentially depend on caspase-8 in hepatocytes, but can be blocked by IDN-7314.
Summary
Background
A strict gluten‐free diet is the cornerstone of treatment for coeliac disease. Studies of gluten‐free diet adherence have rarely used validated instruments. There is a paucity of ...data on long‐term adherence to the gluten‐free diet in the adult population.
Aims
To determine the long‐term adherence to the gluten‐free diet and potential associated factors in a large coeliac disease referral centre population.
Methods
We performed a mailed survey of adults with clinically, serologically and histologically confirmed coeliac disease diagnosed ≥5 years prior to survey. The previously validated Celiac Disease Adherence Test was used to determine adherence. Demographic, socio‐economic and potentially associated factors were analysed with adherence as the outcome.
Results
The response rate was 50.1% of 709 surveyed, the mean time on a gluten‐free diet 9.9 ± 6.4 years. Adequate adherence (celiac disease adherence test score <13) was found in 75.5% of respondents. A higher level of education was associated with adequate adherence (P = 0.002) even after controlling for household income (P = 0.0220). Perceptions of cost, effectiveness of the gluten‐free diet, knowledge of the gluten‐free diet and self‐effectiveness at following the gluten‐free diet correlated with adherence scores (P < 0.001).
Conclusions
Long‐term adherence to a gluten‐free diet was adequate in >75% of respondents. Perceived cost remains a barrier to adherence. Perceptions of effectiveness of gluten‐free diet as well as its knowledge, are potential areas for intervention.
Many bacteria move using a complex, self-assembling nanomachine, the bacterial flagellum. Biosynthesis of the flagellum depends on a flagellar-specific type III secretion system (T3SS), a protein ...export machine homologous to the export machinery of the virulence-associated injectisome. Six cytoplasmic (FliH/I/J/G/M/N) and seven integral-membrane proteins (FlhA/B FliF/O/P/Q/R) form the flagellar basal body and are involved in the transport of flagellar building blocks across the inner membrane in a proton motive force-dependent manner. However, how the large, multi-component transmembrane export gate complex assembles in a coordinated manner remains enigmatic. Specific for most flagellar T3SSs is the presence of FliO, a small bitopic membrane protein with a large cytoplasmic domain. The function of FliO is unknown, but homologs of FliO are found in >80% of all flagellated bacteria. Here, we demonstrate that FliO protects FliP from proteolytic degradation and promotes the formation of a stable FliP-FliR complex required for the assembly of a functional core export apparatus. We further reveal the subcellular localization of FliO by super-resolution microscopy and show that FliO is not part of the assembled flagellar basal body. In summary, our results suggest that FliO functions as a novel, flagellar T3SS-specific chaperone, which facilitates quality control and productive assembly of the core T3SS export machinery.
PDF
