Gasotransmitters: novel regulators of ion channels and transporters

An ROS-Responsive Donor That Self-Reports Its H2S Delivery by Forming a Benzoxazole-Based Fluorophore

Hydrogen sulfide (H2S), an endogenous signaling molecule, is known to play a pivotal role in neuroprotection, vasodilation, and hormonal regulation. To further explore the biological effects of H2S, refined donors that facilitate its biological delivery, especially under specific (patho) physiological conditions, are needed. In the present study, we demonstrate that ortho-substituted, aryl boronate esters provide two unique and distinct pathways for H2S release from thioamide-based donors: Lewis acid-facilitated hydrolysis and reactive oxygen species (ROS)-induced oxidation/cyclization. Through a detailed structure-activity relationship study, donors that resist hydrolysis and release H2S solely via the latter mechanism were identified, which have the added benefit of providing a potentially useful heterocycle as the lone byproduct of this novel chemistry. To highlight this, we developed an ROS-activated donor (QH642) that simultaneously synthesizes a benzoxazole-based fluorophore en route to its H2S delivery. A distinct advantage of this design over earlier self-reporting donors is that fluorophore formation is possible only if H2S has been discharged from the donor. This key feature eliminates the potential for false positives and provides a more accurate depiction of reaction progress and donor delivery of H2S, including in complex cellular environments.

Gases in Sepsis: Novel Mediators and Therapeutic Targets

Sepsis, a potentially lethal condition resulting from failure to control the initial infection, is associated with a dysregulated host defense response to pathogens and their toxins. Sepsis remains a leading cause of morbidity, mortality and disability worldwide. The pathophysiology of sepsis is very complicated and is not yet fully understood. Worse still, the development of effective therapeutic agents is still an unmet need and a great challenge. Gases, including nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S), are small-molecule biological mediators that are endogenously produced, mainly by enzyme-catalyzed reactions. Accumulating evidence suggests that these gaseous mediators are widely involved in the pathophysiology of sepsis. Many sepsis-associated alterations, such as the elimination of invasive pathogens, the resolution of disorganized inflammation and the preservation of the function of multiple organs and systems, are shaped by them. Increasing attention has been paid to developing therapeutic approaches targeting these molecules for sepsis/septic shock, taking advantage of the multiple actions played by NO, CO and H₂S. Several preliminary studies have identified promising therapeutic strategies for gaseous-mediator-based treatments for sepsis. In this review article, we summarize the state-of-the-art knowledge on the pathophysiology of sepsis; the metabolism and physiological function of NO, CO and H₂S; the crosstalk among these gaseous mediators; and their crucial effects on the development and progression of sepsis. In addition, we also briefly discuss the prospect of developing therapeutic interventions targeting these gaseous mediators for sepsis.

The microbiome of oral cavity patients with periodontitis, adhesive and biofilm forming properties

The work characterizes the intestinal microbiota of patients with ischemic stroke, including the spectrum, frequency and number of microorganisms, as well as the spectrum and amount of gas signaling molecules secreted by lactobacilli. It was found that in patients with ischemic stroke, the frequency of the main representatives of normal microflora, Bifidobacterium spp., Lactobacillus spp., Escherichia coli, decreased in 2-3 times, and the same time the prevalence of Clostridia spp., Bacillus spp., Peptostreptococcus spp., Klebsiella spp. increased in 2-3 times; yeast like fungi C. albicans was isolated in 25% of cases. Lactobacilli isolated from the intestinal microbiota of patients with ischemic stroke were represented by a wide variety of species: L. rhamnosus, L. fermentum, L. plantarum, L. brevis, L. pentosus, L. curvatus, L. salivarius. In most cases, they did not produce NO, they released CO 2 times less compared to healthy people. The most active NO producers - L. plantarum, CO - L. rhamnosus.

Ozone and its derivatives in veterinary medicine: A careful appraisal

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In the Vet field, there are lot of scientific publications with missing or incomplete data, poor case reports and papers without a control group or unrepresentative sample.

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Differences between animal and human blood composition, anatomy and physiology must be taken into consideration, especially in therapies not yet fully approved.

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Some practitioners produce their own ozonated solution or autohemotherapy, in the absence of information regarding the compatibility of the material used.

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Other than the properties of the commercial preparations, the standardization of both treatment methods and times influence the results obtained with ozone therapy.

The therapeutic use of ozone and its derivatives in the veterinary medicine it is still in an emergent stage. Gaseous ozone chemical instability makes necessary its extemporaneous preparation and the accordance about ozone treatments with the highest quality standards in publications is of paramount importance. Moreover, the numerous method of administration in different animal species, the prevalence of case reports, the deficiency of consistent evaluation of the outcomes, as well as the lack of standardization of the treatment operating procedures represents an open question for its spreading and official approval. The keywords “ozone”, “ozonated”, “ozonation” “ozonized”, “ozonization”, “oxygen-ozone therapy”, “veterinary”, “pets”, “animal” were used to perform a literature review using PubMed, Cochrane, Google Scholar, Zotero databases with the temporal restriction for published manuscripts starting from 2010. All the researches were critically evaluated, regardless of the impact factor, if any, of the journals in which they were presented. The deepening of the mechanisms of action of this bio-oxidative therapy can open new horizons on its use. The distinctive condition to achieve such a scenario is an improved knowledge of the qualitative/quantitative characteristics of ozone and its derivatives. All with the aim of taking nothing away to the cited original research papers, but of improving the promising therapeutic implications of ozone therapy in veterinary medicine as a standardization stimulus about this therapeutic resource with multiple application specificities.

Adaptation and Probiotic Potential of Lactobacilli, Isolated from the Oral Cavity and Intestines of Healthy People

The present study shows that, from 300 Lactobacillus strains isolated from the oral cavity and large intestine of 600 healthy people, only 9 had high antagonistic activity against pathogens and opportunistic pathogens. All antagonistic strains of lactobacilli have been identified by 16S rRNA sequencing and assigned to four species: Lactobacillus fermentum, Lactobacillus rhamnosus, Lactobacillus plantarum, and Lactobacillus casei. In addition, these lactobacilli appeared to be nonpathogenic and had some probiotic potential: the strains produced lactic acid and bacteriocins, showed high sensitivity to broad-spectrum antibiotics, and were capable of forming biofilms in vitro. With the help of PCR and specific primers, the presence of genes for prebacteriocins in L. plantarum (plnEF, plnJ, plnN) and L. rhamnosus (LGG_02380 and LGG_02400) has been revealed. It was found that intestinal strains of lactobacilli were resistant to hydrochloric acid and bile. Lactobacilli isolated from the oral cavity were characterized by a high degree of adhesion, whereas intestinal strains were characterized by average adhesion. Both types of lactobacilli had medium to high rates of auto-aggregation and hydrophobicity and could coaggregate with pathogens and opportunistic pathogens. Additionally, the ability of the lactobacilli strains to produce gasotransmitters, CH₄, CO₂, C₂H₆, CO, and NH₃, has been revealed.

Neuromodulatory effects and targets of the SCFAs and gasotransmitters produced by the human symbiotic microbiota

The symbiotic gut microbiota plays an important role in the development and homeostasis of the host organism. Its physiological, biochemical, behavioral, and communicative effects are mediated by multiple low molecular weight compounds. Recent data on small molecules produced by gut microbiota in mammalian organisms demonstrate the paramount importance of these biologically active molecules in terms of biology and medicine. Many of these molecules are pleiotropic mediators exerting effects on various tissues and organs. This review is focused on the functional roles of gaseous molecules that perform neuromediator and/or endocrine functions. The molecular mechanisms that underlie the effects of microbial fermentation-derived gaseous metabolites are not well understood. It is possible that these metabolites produce their effects via immunological, biochemical, and neuroendocrine mechanisms that involve endogenous and microbial modulators and transmitters; of considerable importance are also changes in epigenetic transcriptional factors, protein post-translational modification, lipid and mitochondrial metabolism, redox signaling, and ion channel/gap junction/transporter regulation. Recent findings have revealed that interactivity among such modulators/transmitters is a prerequisite for the ongoing dialog between microbial cells and host cells, including neurons. Using simple reliable methods for the detection and measurement of short-chain fatty acids (SCFAs) and small gaseous molecules in eukaryotic tissues and prokaryotic cells, selective inhibitors of enzymes that participate in their synthesis, as well as safe chemical and microbial donors of pleiotropic mediators and modulators of host intestinal microbial ecology, should enable us to apply these chemicals as novel therapeutics and medical research tools.

Diffusible gas transmitter signaling in the copepod crustacean Calanus finmarchicus: identification of the biosynthetic enzymes of nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) using a de novo assembled transcriptome

Neurochemical signaling is a major component of physiological/behavioral control throughout the animal kingdom. Gas transmitters are perhaps the most ancient class of molecules used by nervous systems for chemical communication. Three gases are generally recognized as being produced by neurons: nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S). As part of an ongoing effort to identify and characterize the neurochemical signaling systems of the copepod Calanus finmarchicus, the biomass dominant zooplankton in much of the North Atlantic Ocean, we have mined a de novo assembled transcriptome for sequences encoding the neuronal biosynthetic enzymes of these gases, i.e. nitric oxide synthase (NOS), heme oxygenase (HO) and cystathionine β-synthase (CBS), respectively. Using Drosophila proteins as queries, two NOS-, one HO-, and one CBS-encoding transcripts were identified. Reverse BLAST and structural analyses of the deduced proteins suggest that each is a true member of its respective enzyme family. RNA-Seq data collected from embryos, early nauplii, late nauplii, early copepodites, late copepodites and adults revealed the expression of each transcript to be stage specific: one NOS restricted primarily to the embryo and the other was absent in the embryo but expressed in all other stages, no CBS expression in the embryo, but present in all other stages, and HO expressed across all developmental stages. Given the importance of gas transmitters in the regulatory control of a number of physiological processes, these data open opportunities for investigating the roles these proteins play under different life-stage and environmental conditions in this ecologically important species.