Spectrophotometric Studies of Indolic Compounds from Vinca Minor L.

The most medically representative plant in the Apocynaceae family is Vinca minor. Vinca minor is a perennial, herbaceous plant, commonly known as Saschiu. In the present research we aimed to isolate the indole compounds from Vinca minor L. and to carry out some physico-chemical studies on these compounds: UV-VIS spectroscopy and the determination of the polyphenols content using Folin-Ciocâlteu method. The spectrophotometric study of the alcoholic plant extracts obtained from the leaf and stem of Vinca minor was performed using the UV-VIS spectrophotometric method and a VWR UV-630PC double beam spectrophotometer. Both samples of plant alcoholic extracts obtained from the leaf and from the stem of Vinca minor L. had the specific absorption maxima detected in the range 225-350 nm and the absorbance maximum in both cases was 3.5 (u.a- absorbency units). The total content of polyphenols was determined by the Folin-Ciocâlteu method from alcoholic extracts of different concentrations: 40 percent, 70 percent, 96 percent (T40, T70, T96, F40, F70, F96) obtained from the leaf and stem of Vinca minor plant using the spectrophotometer model JASCO- 550 UV VIS. Regarding the alcoholic extracts obtained from the leaf of Vinca minor L., the concentrations of polyphenols were between 812.50 mg / 100g pv and 1737.50 mg / 100g pv and and in the case of alcoholic extracts obtained from the strain, the results were between 1525.00-3962.50 mg GAE / 100 g pv, results that were in accordance with the literature.

Targeting Dietary and Microbial Tryptophan-Indole Metabolism as Therapeutic Approaches to Colon Cancer

Tryptophan metabolism, via the kynurenine (Kyn) pathway, and microbial transformation of tryptophan to indolic compounds are fundamental for host health; both of which are altered in colon carcinogenesis. Alterations in tryptophan metabolism begin early in colon carcinogenesis as an adaptive mechanism for the tumor to escape immune surveillance and metastasize. The microbial community is a key part of the tumor microenvironment and influences cancer initiation, promotion and treatment response. A growing awareness of the impact of the microbiome on tryptophan (Trp) metabolism in the context of carcinogenesis has prompted this review. We first compare the different metabolic pathways of Trp under normal cellular physiology to colon carcinogenesis, in both the host cells and the microbiome. Second, we review how the microbiome, specifically indoles, influence host tryptophan pathways under normal and oncogenic metabolism. We conclude by proposing several dietary, microbial and drug therapeutic modalities that can be utilized in combination to abrogate tumorigenesis.

Targeting Dietary and Microbial Tryptophan-Indole Metabolism as Therapeutic Approaches to Colon Cancer

Tryptophan metabolism, via the kynurenine (Kyn) pathway, and microbial transformation of tryptophan to indolic compounds, are fundamental for host health; both of which are altered in colon carcinogenesis. Alterations in tryptophan metabolism begin early in colon carcinogenesis as an adaptive mechanism for the tumor to escape immune surveillance and metastasize. The microbial community is a key part of the tumor microenvironment and influences cancer initiation, promotion and treatment response. A growing awareness of the impact of the microbiome on tryptophan (Trp) metabolism in the context of carcinogenesis has prompted this review. We first compare the different metabolic pathways of Trp under normal cellular physiology to colon carcinogenesis, in both the host cells and the microbiome. Second, we review how the microbiome, specifically indoles, influence host tryptophan pathways under normal and oncogenic metabolism. We conclude by proposing several dietary, microbial and drug therapeutic modalities that can be utilized in combination to abrogate tumorigenesis.

Coal-Degrading Bacteria Display Characteristics Typical of Plant Growth Promoting Rhizobacteria

Coal mining produces large quantities of discard that is stockpiled in large dumps. This stockpiled material, termed coal discard, poses an environmental threat emphasising the need for appropriate bioremediation. Here, metagenomic analysis of the 16S rRNA from ten coal-degrading strains previously isolated from coal slurry from discard dumps and from the rhizosphere of diesel-contaminated sites was used to establish genetic relatedness to known plant growth-promoting (PGP) bacteria in the NCBI database. Measurement of indole and ammonium production and solubilisation of P and K were used to screen bacteria for PGP characteristics. BLAST analysis revealed ≥ 99% homology of six isolates with reference PGP strains of Bacillus, Escherichia, Citrobacter, Serratia, Exiguobacterium and Microbacterium, while two strains showed 94% and 91% homology with Proteus. The most competent PGP strains were Proteus strain ECCN 20b, Proteus strain ECCN 23b and Serratia strain ECCN 24b isolated from diesel-contaminated soil. In response to L-trp supplementation, the concentration of indolic compounds (measured as indole-3-acetic acid) increased. Production of ammonium and solubilisation of insoluble P by these strains was also apparent. Only Serratia strain ECCN 24b was capable of solubilising insoluble K. Production of indoles increased following exposure to increasing aliquots of coal discard, suggesting no negative effect of this material on indole production by these coal-degrading bacterial isolates and that these bacteria may indeed possess PGP characteristics.

Mosquito indolergic receptors belong to an ancient and functionally conserved Dipteran gene lineage

Diptera is a megadiverse group of flies with sophisticated chemical detection systems, which exploits an incredible variety of ecological niches. Among the vast array of odorants in natural environments, indoles stand out as playing crucial roles in mediating fly behavior. In mosquitoes, indolic compounds are detected by an ancient class of conserved indolergic Odorant Receptors (indolORs). In this study, we have identified a set of 92 putative indolOR genes encoded in the genomes of Nematoceran and Brachyceran flies, resolved their phylogenetic relationships, and defined conserved elements in their gene structures. Further, we have quantified indolOR transcript abundance in the antennae of the housefly, Musca domestica, and have characterized MdomOR30a as a skatole receptor using a heterologous expression system. The presence of indolORs in species operating in different ecological contexts suggests that indoles act as pleiotropic signals for resource exploitation at multiple developmental stages. Further characterization of indolORs will impact our understanding of insect chemical ecology and will provide targets for the development of novel odor-based tools that can be integrated into existing vector surveillance and control programs.

Net release and uptake of xenometabolites across intestinal, hepatic, muscle, and renal tissue beds in healthy conscious pigs

Xenometabolites from microbe origins influence host health and disease, but absorption and tissue uptake of these metabolites remain speculative. Results herein are the first to demonstrate in vivo organ uptake and release of these metabolites. We used a conscious catheterized pig model to confirm gastrointestinal origins for several xenometabolites (e.g., indolic compounds, 4-hydroxyphenyllactic acid, dodecanendioic acid, and phenylacetylgycine). Liver and kidney were major sites for xenometabolite uptake, likely highlighting liver conjugation metabolism and renal excretion.

P0703IDENTIFICATION AND QUANTIFICATION OF UREMIC TOXIN PRECURSORS-GENERATING GUT BACTERIA IN CHRONIC KIDNEY DISEASE

Background and Aims In chronic kidney disease (CKD), impaired kidney function results in the accumulation of uremic toxins, which exert deleterious biological effects, contributing to cardiovascular morbidity and mortality. Protein-bound uremic toxins (PBUTs), such as p-cresyl sulfate, indoxyl sulfate and indole-3-acetic acid (IAA), originate from phenolic and indolic compounds, which are end products of the gut bacterial metabolization of aromatic amino acids (AAA). This study investigated the microbial composition in different stages of CKD by isolating, identifying and quantifying PBUT precursor-generating bacteria from fecal samples. Method Using fecal samples from patients in CKD stage 1 (n=6) and stage 5 (n=6), bacteria were cultured in a yeast casitone fatty acid glucose broth medium supplemented with AAA under aerobic (2d at 37°C) and anaerobic conditions (7d at 37°C), and confirmed as PBUT precursor-generating bacteria based on their generation capacity of phenolic and indolic compounds, measured with (U)HPLC. Next, fecal DNA from 14 controls, 111 non-dialyzed and 27 dialyzed CKD patients was used to quantify the total bacterial number but also of 11 of the identified PBUT precursor-generating bacteria with qPCR. Using a Kruskal-Wallis test, bacterial loads were compared between the different CKD stages and control. Correlations between disease stages (control and CKD 1-5) and the abundance of bacterial species were assessed with the Spearman’s rank test. Results In total, 150 different bacterial species were isolated from the CKD fecal samples, of which 101 were identified and 92 classified as PBUT precursor-generating bacteria. In general, p-cresol and phenol were mainly generated under anaerobic conditions, while indole and IAA were generated under both aerobic and anaerobic conditions. Phenolic compounds and IAA were predominantly generated by bacterial species belonging to the Bacteroidaceae, Clostridiaceae, Enterococcaceae and Tannerellaceae, while indolic compounds were mainly generated by Bifidobacteriaceae and Enterobacteriaceae. Quantitative analysis of 11 confirmed PBUT precursor-generating bacteria revealed a higher abundance of Streptococcus spp. and Enterobacteriaceae in fecal samples from HD patients compared to controls and early CKD stages, and for Roseburia spp. compared to CKD 5. Moreover, in HD, the abundance of Clostridioides difficile and Lactobacillus spp. was increased compared to CKD 1-5, and of Escherichia coli compared to control (all p>0.05). The abundance of Bacteroides spp., Faecalibacterium prausnitzii, Akkermansia muciniphila and Bifidobacterium spp. as well as the total number of bacteria was comparable among the different CKD stages and controls. Finally, decrease in kidney function (ranging from control to CKD 5) positively correlated with the abundance of Enterobacteriaceae (rs=0.210), and E. coli (rs=0.286), while an inverse correlation was found with Streptococcus spp. (rs=-0.255), Butyricoccus spp. (rs=-0.326), F. prausnitzii (rs=-0.250), Roseburia spp. (rs=-0.342) and Bifidobacterium spp. (rs=-0.303) (all p>0.05). Conclusion The identified PBUT precursor-generating bacteria are potential targets to reduce the plasma PBUT levels in CKD. In addition, in this CKD cohort, based on qPCR, an altered gut microbial composition with the progression of CKD could be established/confirmed.