Divergent Synthesis of Unsymmetrical Bis-heteroaryl Ketones via Base-Promoted Cascade Reactions of 1,2-Alkynedione-Derived N-Propargylic ß-Enaminones.

Herein we disclose a transition-metal-free, one-pot two-step strategy for the synthesis of unsymmetrical bis-heteroaryl ketones. N-propargylic ß-enaminones generated by the Michael addition of propargylamines onto heteroaryl 1,2-alkynediones have been utilized as synthetic equivalents of pyridine or pyrrole scaffolds. The use of alcohol as a solvent resulted in the formation of 2-alkoxylated pyridine scaffold, whereas the use of DMSO promoted the formation of a pyrrole motif.

Non-SCFA microbial metabolites associated with fiber fermentation and host health.

Dietary fiber is degraded by commensal gut microbes to yield host-beneficial short-chain fatty acids (SCFAs), but personalized responses to fiber supplementation highlight a role for other microbial metabolites in shaping host health. In this review we summarize recent findings from dietary fiber intervention studies describing health impacts attributed to microbial metabolites other than SCFAs, particularly secondary bile acids (2°BAs), aromatic amino acid derivatives, neurotransmitters, and B vitamins. We also discuss shifts in microbial metabolism occurring through altered maternal dietary fiber intake and agricultural practices, which warrant further investigation. To optimize the health benefits of dietary fibers, it is essential to survey a range of metabolites and adapt recommendations on a personalized basis, according to the different functional aspects of the microbiome.

Gut microbial factors predict disease severity in a mouse model of multiple sclerosis.

Gut bacteria are linked to neurodegenerative diseases but the risk factors beyond microbiota composition are limited. Here we used a pre-clinical model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), to identify microbial risk factors. Mice with different genotypes and complex microbiotas or six combinations of a synthetic human microbiota were analysed, resulting in varying probabilities of severe neuroinflammation. However, the presence or relative abundances of suspected microbial risk factors failed to predict disease severity. Akkermansia muciniphila, often associated with MS, exhibited variable associations with EAE severity depending on the background microbiota. Significant inter-individual disease course variations were observed among mice harbouring the same microbiota. Evaluation of microbial functional characteristics and host immune responses demonstrated that the immunoglobulin A coating index of certain bacteria before disease onset is a robust individualized predictor of disease development. Our study highlights the need to consider microbial community networks and host-specific bidirectional interactions when aiming to predict severity of neuroinflammation.

Gut colonization with antibiotic resistance Escherichia coli pathobionts leads to disease severity in ulcerative colitis.

AIM: Escherichia coli is a Gram-negative commensal of human gut. Surprisingly, the role of E. coli in the pathogenesis of ulcerative colitis (UC) has not been explored till date. METHODS: Human gut microbiota composition and meta-gut resistome was evaluated using metagenomics. Antibiotic susceptibility of E. coli isolates against different class of antibiotics was investigated. Further, the genome sequence analysis of E. coli isolates was performed to get insight into the antimicrobial resistance (AMR) mechanism and virulence factors. Gut proteome of UC and non-UC was examined to understand the effect of resistant bacteria on host physiology. RESULTS: In UC patients, meta-gut resistome was found to be dominated by AMR genes (829) compared to healthy control (HC) [518]. Metagenome study revealed higher prevalence of AMR genes in rural population (378 in HC; 607 in UC) compared to urban (340 in HC; 578 in UC). Approximately, 40% of all E. coli isolates were multi-drug resistant with higher prevalence in UC (43.75%) compared to HC (33.33%). Up-regulated expression of antimicrobial human proteins (lactotransferrin, azurocidin, cathepsin G, neutrophil elastase, and neutrophil defensin 3) and immuneproteins (Protein S100-A9 and Protein S100-A8) suggest microbial infection in UC gut. CONCLUSIONS: In addition to the conventional culturomics method, multi-omics strategy provides deeper insights into the disease etiology, emergence of pathobionts, andits role in the disruption of the healthy gut environment in UC patients.

Effect of real-time oxygen consumption versus fixed flow-based low flow anesthesia on oxygenation and perfusion: a randomized, single-blind study.

Although low-flow anesthesia is widely used due to its various advantages, there are concerns about potential and relative hypoxia. Furthermore, oxygen is also a drug with benefits and adverse effects. We aimed to evaluate and compare the effect of real-time oxygen consumption versus fixed flow-based low flow anesthesia on oxygenation and perfusion and to compare the economic benefits. With ethical approvals and informed consent, participants were randomly assigned to a dynamic group (13 males, and 27 females) receiving fresh gas flows depending on real-time oxygen consumption (dynamic O2: N2O), and a fixed group (20 males, and 13 females) receiving fixed fresh gas flows of 600 mL/min (with O2: N2O of 1:1). Oxygen partial pressure and serum lactate were comparable between groups. However, isoflurane consumed and costs incurred were significantly different. Total oxygen consumption per minute was also significantly lower in the dynamic group than the fixed group. No episodes of hypoxia were observed in either group. Real-time oxygen consumption-based low flow anesthesia is feasible and cost-effective without affecting the patient's global perfusion and outcome.

An uncommon presentation of segmental Becker's nevus involving the T4 dermatome.

This case report explores a rare manifestation of Becker's nevus, where the patient exhibited an unusual dermatomal distribution featuring a hyperpigmented, irregular patch with associated hypertrichosis on the T4 segment. While Becker's nevus is a well-known dermatological condition typically observed in the upper back region, instances of dermatomal distribution are exceptionally uncommon. This case presents a unique occurrence of segmental Becker's nevus, highlighting the atypical presentation of this condition.

An Adsorption Based Downstream Processing Approach for Penicillin V from a Penicillium chrysogenum BIONCL I22 Culture Filtrate.

Penicillin V (phenoxy methyl penicillin) is highly sought after among natural penicillins because of its exceptional acid stability and effectiveness against common skin and respiratory infections. Given its wide-ranging therapeutic uses, there is a need to establish a greener method for its maximum recovery to reduce the carbon footprint. Here, we have identified and validated optimized operational conditions for resin-based penicillin V recovery. It was observed that Amberlite XAD4 had the highest penicillin V hydrophobic adsorption capacity among the other screened resins. Kinetic and isothermal studies using linear and nonlinear regression analysis showed that the adsorption process well fitted with pseudo-second-order kinetics (R 2 = 0.9816) and the Freundlich adsorption isotherm model (R 2 = 0.9871). Adsorption equilibrium was attained within 4 h, while maximum adsorption was observed at 3 mg/mL penicillin V concentration. Furthermore, the optimized extraction protocol was compared with the conventional butyl acetate-based downstream processing. Under optimum conditions resin-based penicillin V recovery was 2-fold higher as compared to the solvent extraction method and the resin could be reused for over six cycles without compromising the yield. These findings signify substantial progress toward the development of an environmentally sustainable approach for penicillin V recovery and a potentially viable method for extractive fermentation.

Peripheral blood smear - An expeditious test in the preliminary diagnosis of bone marrow embolism in a case of multiple fractures: A case report.

ABSTRACT: Bone marrow embolism is known to occur after fractures of long bones such as the femur and pelvis. We report a case of multiple fractures in a 32-year-old female patient, demonstrating bone marrow elements in the peripheral blood as early as 2 hours after trauma. This is the first case being reported with an ante-mortem demonstration of circulating marrow emboli in the peripheral blood, while the previously reported cases have demonstrated the emboli in post-mortem examination. A careful correlation of the clinical history of trauma, hematology auto-analyzer results, and the presence of bone marrow particles and fat globules in peripheral blood helped in arriving at the diagnosis of fat embolism in our case irrefutably.

Diet-driven differential response of Akkermansia muciniphila modulates pathogen susceptibility.

The erosion of the colonic mucus layer by a dietary fiber-deprived gut microbiota results in heightened susceptibility to an attaching and effacing pathogen, Citrobacter rodentium. Nevertheless, the questions of whether and how specific mucolytic bacteria aid in the increased pathogen susceptibility remain unexplored. Here, we leverage a functionally characterized, 14-member synthetic human microbiota in gnotobiotic mice to deduce which bacteria and functions are responsible for the pathogen susceptibility. Using strain dropouts of mucolytic bacteria from the community, we show that Akkermansia muciniphila renders the host more vulnerable to the mucosal pathogen during fiber deprivation. However, the presence of A. muciniphila reduces pathogen load on a fiber-sufficient diet, highlighting the context-dependent beneficial effects of this mucin specialist. The enhanced pathogen susceptibility is not owing to altered host immune or pathogen responses, but is driven by a combination of increased mucus penetrability and altered activities of A. muciniphila and other community members. Our study provides novel insights into the mechanisms of how discrete functional responses of the same mucolytic bacterium either resist or enhance enteric pathogen susceptibility.

A viscosity measurement technique for ultra-low sample volumes.

We describe a unique method to measure the viscosity of liquids based on the fluid mechanics of thin films. A drop of sample is spread over a substrate by contacting a blade with the drop and moving the blade across the substrate. The thickness of the film is determined by the capillary number, which measures the competition between the viscous force that smears the liquid over the glass slide and the surface tension that resists the deformation of the interface. We show that the length of the smear for a fixed sample volume is also set by capillary number and can be used as a reliable measure of fluid viscosity. The technique is especially suitable for viscosity measurements of biological fluids where viscosities are low and sample sizes are small. The technique can detect small changes in blood viscosity enabling it to be used as a non-specific, screening tool for diseases and therapeutic interventions.

Multicomponent (bio)markers for obesity risk prediction: a scoping review protocol.

INTRODUCTION: Despite international efforts, the number of individuals struggling with obesity is still increasing. An important aspect of obesity prevention relates to identifying individuals at risk at early stage, allowing for timely risk stratification and initiation of countermeasures. However, obesity is complex and multifactorial by nature, and one isolated (bio)marker is unlikely to enable an optimal risk stratification and prognosis for the individual; rather, a combined set is required. Such a multicomponent interpretation would integrate biomarkers from various domains, such as classical markers (eg, anthropometrics, blood lipids), multiomics (eg, genetics, proteomics, metabolomics), lifestyle and behavioural attributes (eg, diet, physical activity, sleep patterns), psychological traits (mental health status such as depression) and additional host factors (eg, gut microbiota diversity), also by means of advanced interpretation tools such as machine learning. In this paper, we will present a protocol that will be employed for a scoping review that attempts to summarise and map the state-of-the-art in the area of multicomponent (bio)markers related to obesity, focusing on the usability and effectiveness of such biomarkers. METHODS AND ANALYSIS: PubMed, Scopus, CINAHL and Embase databases will be searched using predefined key terms to identify peer-reviewed articles published in English until January 2024. Once downloaded into EndNote for deduplication, CADIMA will be employed to review and select abstracts and full-text articles in a two-step procedure, by two independent reviewers. Data extraction will then be carried out by several independent reviewers. Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews and Peer Review of Electronic Search Strategies guidelines will be followed. Combinations employing at least two biomarkers from different domains will be mapped and discussed. ETHICS AND DISSEMINATION: Ethical approval is not required; data will rely on published articles. Findings will be published open access in an international peer-reviewed journal. This review will allow guiding future directions for research and public health strategies on obesity prevention, paving the way towards multicomponent interventions.

Opposing diet, microbiome, and metabolite mechanisms regulate inflammatory bowel disease in a genetically susceptible host.

Inflammatory bowel diseases (IBDs) are chronic conditions characterized by periods of spontaneous intestinal inflammation and are increasing in industrialized populations. Combined with host genetics, diet and gut bacteria are thought to contribute prominently to IBDs, but mechanisms are still emerging. In mice lacking the IBD-associated cytokine, interleukin-10, we show that a fiber-deprived gut microbiota promotes the deterioration of colonic mucus, leading to lethal colitis. Inflammation starts with the expansion of natural killer cells and altered immunoglobulin-A coating of some bacteria. Lethal colitis is then driven by Th1 immune responses to increased activities of mucin-degrading bacteria that cause inflammation first in regions with thinner mucus. A fiber-free exclusive enteral nutrition diet also induces mucus erosion but inhibits inflammation by simultaneously increasing an anti-inflammatory bacterial metabolite, isobutyrate. Our findings underscore the importance of focusing on microbial functions-not taxa-contributing to IBDs and that some diet-mediated functions can oppose those that promote disease.

Akkermansia muciniphila and Parabacteroides distasonis synergistically protect from colitis by promoting ILC3 in the gut.

Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the gastrointestinal tract. The etiology of IBD remains elusive, but the disease is suggested to arise from the interaction of environmental and genetic factors that trigger inadequate immune responses and inflammation in the intestine. The gut microbiome majorly contributes to disease as an environmental variable, and although some causative bacteria are identified, little is known about which specific members of the microbiome aid in the intestinal epithelial barrier function to protect from disease. While chemically inducing colitis in mice from two distinct animal facilities, we serendipitously found that mice in one facility showed remarkable resistance to disease development, which was associated with increased markers of epithelial barrier integrity. Importantly, we show that Akkermansia muciniphila and Parabacteroides distasonis were significantly increased in the microbiota of resistant mice. To causally connect these microbes to protection against disease, we colonized susceptible mice with the two bacterial species. Our results demonstrate that A. muciniphila and P. distasonis synergistically drive a protective effect in both acute and chronic models of colitis by boosting the frequency of type 3 innate lymphoid cells in the colon and by improving gut epithelial integrity. Altogether, our work reveals a combined effort of commensal microbes in offering protection against severe intestinal inflammation by shaping gut immunity and by enhancing intestinal epithelial barrier stability. Our study highlights the beneficial role of gut bacteria in dictating intestinal homeostasis, which is an important step toward employing microbiome-driven therapeutic approaches for IBD clinical management. IMPORTANCE: The contribution of the gut microbiome to the balance between homeostasis and inflammation is widely known. Nevertheless, the etiology of inflammatory bowel disease, which is known to be influenced by genetics, immune response, and environmental cues, remains unclear. Unlocking novel players involved in the dictation of a protective gut, namely, in the microbiota component, is therefore crucial to develop novel strategies to tackle IBD. Herein, we revealed a synergistic interaction between two commensal bacterial strains, Akkermansia muciniphila and Parabacteroides distasonis, which induce protection against both acute and chronic models of colitis induction, by enhancing epithelial barrier integrity and promoting group 3 innate lymphoid cells in the colonic mucosa. This study provides a novel insight on how commensal bacteria can beneficially act to promote intestinal homeostasis, which may open new avenues toward the use of microbiome-derived strategies to tackle IBD.

Genome sequencing and protein modeling unraveled the 2AP biosynthesis in Bacillus cereus DB25.

2-Acetyl-1-pyrroline (2AP) is an important and major flavor aroma compound responsible for the fragrance of basmati rice, cheese, wine, and several other food products. Biosynthesis of 2AP in aromatic rice and a few other plant species is associated with a recessive Betaine aldehyde dehydrogenase 2 (BADH2) gene. However, the literature is scant on the relationship between the functional BADH2 gene and 2AP biosynthesis in prokaryotic systems. Therefore, in the present study, we aimed to explore the functionality of the BADH2 gene for 2AP biosynthesis in 2AP synthesizing rice rhizobacterial isolate Bacillus cereus DB25 isolated from the rhizosphere of basmati rice (Oryza sativa L.). Full-length BcBADH2 sequence was obtained through whole genome sequencing (WGS) and further confirmed through traditional PCR and Sanger sequencing. Then the functionality of the BcBADH2 gene was evaluated in-silico through bioinformatics analysis and protein docking studies and further experimentally validated through enzyme assay. The sequencing and bioinformatics analysis results revealed a full-length 1485 bp BcBADH2 coding sequence without any deletion or premature stop codons. Full-length BcBADH2 was found to encode a fully functional protein of 54.08 kDa with pI of 5.22 and showed the presence of the conserved amino acids responsible for enzyme activity. The docking studies confirmed a good affinity between the protein and its substrate whereas the presence of BcBADH2 enzyme activity confirmed the functionality of BADH2 enzyme in B. cereus DB25. In conclusion, the findings of the present study suggest that B. cereus DB25 is able to synthesize 2AP despite a functional BADH2 gene and there may be a different molecular mechanism responsible for 2AP biosynthesis in bacterial systems, unlike that found in aromatic rice and other eukaryotic plant species.

Draft genome sequence of Kluyvera ascorbata HAK22 isolated from human feces.

The whole genome sequence of rare human pathogen Kluyvera ascorbata strain HAK22 is reported. The K. ascorbata HAK22 was isolated from healthy human from Gurugram, Haryana, India. The draft genome has a length of 4.7 Mbp, with 54.36% GC content and 4,411 proteins, 4,470 genes, and 18 antimicrobial resistance genes.

Nucleophilic Acylation-Annulation Cascade of 2-Chlorobenzonitriles Using Aldehydes Triggered by N-Heterocyclic Carbenes.

A general and practical route to the synthesis of functionalized isoindolin-2-ones from commercially available aldehydes and 2-chlorobenzonitriles under mild conditions initiated by N-heterocyclic carbenes is presented. The catalytically generated Breslow intermediates from aldehydes and carbenes underwent smooth SNAr with 2-chlorobenzonitriles followed by annulation triggered by adventitious water present in DMF to furnish the functionalized isoindolin-2-ones in good to excellent yields.

Enantioselective Synthesis of C-O Axially Chiral Diaryl Ethers by NHC-Catalyzed Atroposelective Desymmetrization.

Axially chiral diaryl ethers, a distinguished class of atropisomers possessing unique dual C-O axis, hold immense potential for diverse research domains. In contrast to the catalytic enantioselective synthesis of conventional single axis bearing atropisomers, the atroposelective synthesis of axially chiral ethers containing flexible C-O axis remains a significant challenge. Herein, we demonstrate the first N-heterocyclic carbene (NHC)-catalyzed synthesis of axially chiral diaryl ethers via atroposelective esterification of dialdehyde-containing diaryl ethers. Mechanistically, the reaction proceeds via NHC-catalyzed desymmetrization strategy to afford the corresponding axially chiral diaryl ether atropisomers in good yields and high enantioselectivities under mild conditions. The derivatization of the synthesized product expands the utility of present strategy via access to a library of C-O axially chiral compounds. The temperature dependency and preliminary investigations on the racemization barrier of C-O bonds are also presented.

Akkermansia muciniphila exacerbates food allergy in fibre-deprived mice.

Alterations in the gut microbiome, including diet-driven changes, are linked to the rising prevalence of food allergy. However, little is known about how specific gut bacteria trigger the breakdown of oral tolerance. Here we show that depriving specific-pathogen-free mice of dietary fibre leads to a gut microbiota signature with increases in the mucin-degrading bacterium Akkermansia muciniphila. This signature is associated with intestinal barrier dysfunction, increased expression of type 1 and 2 cytokines and IgE-coated commensals in the colon, which result in an exacerbated allergic reaction to food allergens, ovalbumin and peanut. To demonstrate the causal role of A. muciniphila, we employed a tractable synthetic human gut microbiota in gnotobiotic mice. The presence of A. muciniphila within the microbiota, combined with fibre deprivation, resulted in stronger anti-commensal IgE coating and innate type-2 immune responses, which worsened symptoms of food allergy. Our study provides important insights into how gut microbes can regulate immune pathways of food allergy in a diet-dependent manner.