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Nature Metabolism Nov 2023Ammonia has been long recognized as a metabolic waste product with well-known neurotoxic effects. However, little is known about the beneficial function of endogenous...
Ammonia has been long recognized as a metabolic waste product with well-known neurotoxic effects. However, little is known about the beneficial function of endogenous ammonia. Here, we show that gut ammonia links microbe nitrogen metabolism to host stress vulnerability by maintaining brain glutamine availability in male mice. Chronic stress decreases blood ammonia levels by altering gut urease-positive microbiota. A representative urease-producing strain, Streptococcus thermophilus, can reverse depression-like behaviours induced by gut microbiota that was altered by stress, whereas pharmacological inhibition of gut ammonia production increases stress vulnerability. Notably, abnormally low blood ammonia levels limit the brain's availability of glutamine, a key metabolite produced by astrocytes that is required for presynaptic γ-aminobutyric acid (GABA) replenishment and confers stress vulnerability through cortical GABAergic dysfunction. Of therapeutic interest, ammonium chloride (NHCl), a commonly used expectorant in the clinic, can rescue behavioural abnormalities and GABAergic deficits in mouse models of depression. In sum, ammonia produced by the gut microbiome can help buffer stress in the host, providing a gut-brain signalling basis for emotional behaviour.
Topics: Mice; Male; Animals; Gastrointestinal Microbiome; Ammonia; Glutamine; Urease; Astrocytes
PubMed: 37872351
DOI: 10.1038/s42255-023-00909-5 -
Journal of Functional Biomaterials Jun 2023Medical gloves, along with masks and gowns, serve as the initial line of defense against potentially infectious microorganisms and hazardous substances in the health... (Review)
Review
Medical gloves, along with masks and gowns, serve as the initial line of defense against potentially infectious microorganisms and hazardous substances in the health sector. During the COVID-19 pandemic, medical gloves played a significant role, as they were widely utilized throughout society in daily activities as a preventive measure. These products demonstrated their value as important personal protection equipment (PPE) and reaffirmed their relevance as infection prevention tools. This review describes the evolution of medical gloves since the discovery of vulcanization by Charles Goodyear in 1839, which fostered the development of this industry. Regarding the current market, a comparison of the main properties, benefits, and drawbacks of the most widespread types of sanitary gloves is presented. The most common gloves are produced from natural rubber (NR), polyisoprene (IR), acrylonitrile butadiene rubber (NBR), polychloroprene (CR), polyethylene (PE), and poly(vinyl chloride) (PVC). Furthermore, the environmental impacts of the conventional natural rubber glove manufacturing process and mitigation strategies, such as bioremediation and rubber recycling, are addressed. In order to create new medical gloves with improved properties, several biopolymers (e.g., poly(vinyl alcohol) and starch) and additives such as biodegradable fillers (e.g., cellulose and chitin), reinforcing fillers (e.g., silica and cellulose nanocrystals), and antimicrobial agents (e.g., biguanides and quaternary ammonium salts) have been evaluated. This paper covers these performance-enhancing materials and describes different innovative prototypes of gloves and coatings designed with them.
PubMed: 37504844
DOI: 10.3390/jfb14070349 -
Nature Communications Oct 2023Ammonium (NH), a breakdown product of amino acids that can be toxic at high levels, is detected by taste systems of organisms ranging from C. elegans to humans and has...
Ammonium (NH), a breakdown product of amino acids that can be toxic at high levels, is detected by taste systems of organisms ranging from C. elegans to humans and has been used for decades in vertebrate taste research. Here we report that OTOP1, a proton-selective ion channel expressed in sour (Type III) taste receptor cells (TRCs), functions as sensor for ammonium chloride (NHCl). Extracellular NHCl evoked large dose-dependent inward currents in HEK-293 cells expressing murine OTOP1 (mOTOP1), human OTOP1 and other species variants of OTOP1, that correlated with its ability to alkalinize the cell cytosol. Mutation of a conserved intracellular arginine residue (R292) in the mOTOP1 tm 6-tm 7 linker specifically decreased responses to NHCl relative to acid stimuli. Taste responses to NHCl measured from isolated Type III TRCs, or gustatory nerves were strongly attenuated or eliminated in an Otop1 mouse strain. Behavioral aversion of mice to NHCl, reduced in Skn-1a mice lacking Type II TRCs, was entirely abolished in a double knockout with Otop1. These data together reveal an unexpected role for the proton channel OTOP1 in mediating a major component of the taste of NHCl and a previously undescribed channel activation mechanism.
Topics: Animals; Humans; Mice; Ammonium Chloride; HEK293 Cells; Protons; Taste; Taste Buds
PubMed: 37798269
DOI: 10.1038/s41467-023-41637-4 -
Antibiotics (Basel, Switzerland) Aug 2023Ammonium group containing polymers possess inherent antimicrobial properties, effectively eliminating or preventing infections caused by harmful microorganisms. Here,...
Ammonium group containing polymers possess inherent antimicrobial properties, effectively eliminating or preventing infections caused by harmful microorganisms. Here, homopolymers based on monomers containing ammonium groups were synthesized via Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT) and evaluated as potential antibacterial agents. The antimicrobial activity was evaluated against Gram-positive ( and ) and Gram-negative bacteria ( and ). Three polymers, poly(diallyl dimethyl ammonium chloride), poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and poly(vinyl benzyl trimethylammonium chloride), were examined to explore the effect of molecular weight (10 kDa, 20 kDa, and 40 kDa) on their antimicrobial activity and toxicity to mammalian cells. The mechanisms of action of the polymers were investigated with dye-based assays, while Scanning Electron Microscopy (SEM) showed collapsed and fused bacterial morphologies due to the interactions between the polymers and components of the bacterial cell envelope, with some polymers proving to be bactericidal and others bacteriostatic, while being non-hemolytic. Among all the homopolymers, the most active, non-Gram-specific polymer was poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride), with a molecular weight of 40 kDa, with minimum inhibitory concentrations between 16 and 64 µg/mL, showing a bactericidal mode of action mediated by disruption of the cytoplasmic membrane. This homopolymer could be useful in biomedical applications such as surface dressings and in areas such as eye infections.
PubMed: 37627740
DOI: 10.3390/antibiotics12081320 -
Carbohydrate Polymers Oct 2023The management of deep burn injuries is extremely challenging, ascribed to their delayed wound healing rate, susceptibility for bacterial infections, pain, and increased...
The management of deep burn injuries is extremely challenging, ascribed to their delayed wound healing rate, susceptibility for bacterial infections, pain, and increased risk of hypertrophic scarring. In our current investigation, a series of composite nanofiber dressings (NFDs) based on polyurethane (PU) and marine polysaccharides (i.e., hydroxypropyl trimethyl ammonium chloride chitosan, HACC and sodium alginate, SA) were accomplished by electrospinning and freeze-drying protocols. The 20(R)-ginsenoside Rg3 (Rg3) was further loaded into these NFDs to inhibit the formation of excessive wound scars. The PU/HACC/SA/Rg3 dressings showed a sandwich-like structure. The Rg3 was encapsulated in the middle layers of these NFDs and slowly released over 30 days. The PU/HACC/SA and PU/HACC/SA/Rg3 composite dressings demonstrated superior wound healing potentials over other NFDs. These dressings also displayed favorable cytocompatibility with keratinocytes and fibroblasts and could dramatically accelerate epidermal wound closure rate following 21 days of the treatment of a deep burn wound animal model. Interestingly, the PU/HACC/SA/Rg3 obviously reduced the excessive scar formation, with a collagen type I/III ratio closer to the normal skin. Overall, this study represented PU/HACC/SA/Rg3 as a promising multifunctional wound dressing, which promoted the regeneration of burn skins and attenuated scar formation.
Topics: Animals; Cicatrix; Polyurethanes; Nanofibers; Wound Healing; Burns; Alginates; Bandages
PubMed: 37364955
DOI: 10.1016/j.carbpol.2023.121085 -
Journal of Pharmaceutical Analysis Dec 2023The () of cation-chloride cotransporters (CCCs) comprises potassium chloride cotransporters (KCCs, e.g. KCC1, KCC2, KCC3, and KCC4)-mediated Cl extrusion, and sodium... (Review)
Review
The () of cation-chloride cotransporters (CCCs) comprises potassium chloride cotransporters (KCCs, e.g. KCC1, KCC2, KCC3, and KCC4)-mediated Cl extrusion, and sodium potassium chloride cotransporters (N[K]CCs, NKCC1, NKCC2, and NCC)-mediated Cl loading. The CCCs play vital roles in cell volume regulation and ion homeostasis. Gain-of-function or loss-of-function of these ion transporters can cause diseases in many tissues. In recent years, there have been considerable advances in our understanding of CCCs' control mechanisms in cell volume regulations, with many techniques developed in studying the functions and activities of CCCs. Classic approaches to directly measure CCC activity involve assays that measure the transport of potassium substitutes through the CCCs. These techniques include the ammonium pulse technique, radioactive or nonradioactive rubidium ion uptake-assay, and thallium ion-uptake assay. CCCs' activity can also be indirectly observed by measuring γ-aminobutyric acid (GABA) activity with patch-clamp electrophysiology and intracellular chloride concentration with sensitive microelectrodes, radiotracer Cl, and fluorescent dyes. Other techniques include directly looking at kinase regulatory sites phosphorylation, flame photometry, Na uptake assay, structural biology, molecular modeling, and high-throughput drug screening. This review summarizes the role of CCCs in genetic disorders and cell volume regulation, current methods applied in studying CCCs biology, and compounds developed that directly or indirectly target the CCCs for disease treatments.
PubMed: 38223443
DOI: 10.1016/j.jpha.2023.09.002 -
IUCrData Oct 2023The asymmetric unit in the title salt, (CHN)[SnCl(CHClF)], features a di-butyl-ammonium cation in a general position and a diorganotin tetra-chloride dianion, ....
The asymmetric unit in the title salt, (CHN)[SnCl(CHClF)], features a di-butyl-ammonium cation in a general position and a diorganotin tetra-chloride dianion, . tetra-chlorido-bis-(3-trifuoro-methyl-phen-yl)stannate(IV), located on a centre of inversion; the Sn atom is octa-hedrally coordinated. In the crystal, charge-assisted N-H⋯Cl hydrogen bonds along with C-H⋯F contacts occur within supra-molecular layers that inter-digitate along the -axis direction.
PubMed: 37936588
DOI: 10.1107/S2414314623009136 -
Clinical, Cosmetic and Investigational... 2023The recent global pandemic has resulted in increased use of quaternary ammonium compounds (QACs). Currently, QACs are active ingredients in 292 disinfectants recommended... (Review)
Review
The recent global pandemic has resulted in increased use of quaternary ammonium compounds (QACs). Currently, QACs are active ingredients in 292 disinfectants recommended by the US EPA for use against SARS-CoV-2. Among QACs, benzalkonium chloride (BAK), cetrimonium bromide (CTAB), cetrimonium chloride (CTAC), didecyldimethylammonium chloride (DDAC), cetrimide, quaternium-15, cetylpyridinium chloride (CPC), and benzethonium chloride (BEC) were all identified as potential culprits of skin sensitivity. Given their widespread utilization, additional research is needed to better classify their dermal effects and identify other cross-reactors. In this review, we aimed to expand our knowledge about these QACs to further dissect its potential allergic and irritant dermal effects on healthcare workers during COVID-19.
PubMed: 37409071
DOI: 10.2147/CCID.S410910 -
PloS One 2023Erythropalum scandens Bl. is a woody vegetable with high nitrogen demand that inhabits southern China. Ammonium and nitrate are the two main forms of inorganic nitrogen...
Erythropalum scandens Bl. is a woody vegetable with high nitrogen demand that inhabits southern China. Ammonium and nitrate are the two main forms of inorganic nitrogen that plants directly absorb. A pot experiment was performed to determine the growth, physiological responses, and preferences of 12-month-old E. scandens seedlings for ammonium and nitrate. Aboveground and underground growth indexes, biomass, physiological and biochemical indexes (chlorophyll [Chl], soluble sugar, soluble protein and free proline contents), and substrate pH and nitrogen contents were determined under different nitrate and ammonium ratios (0 NO3-: 100 NH4+, 25 NO3-: 75 NH4+, 50 NO3-: 50 NH4+, 75 NO3-: 25 NH4+, and 100 NO3-: 0 NH4+), and the control (0 NO3-: 0 NH4+). The results showed that ammonium and nitrate improved the growth and physiological status of E. scandens seedlings in most of the treatments compared to the control. The aboveground growth status and biomass accumulation of E. scandens seedlings were significantly better under the 0 NO3-: 100 NH4+ treatment during fertilization compared with all other treatments. However, the growth status of the underground parts was not significantly different among treatments. Significant differences in osmoregulator content, except for soluble sugars, and Chl content were observed. Soluble sugars and soluble proteins were highest under the 0 NO3-: 100 NH4+ treatment at the end of fertilization (day 175). However, free proline accumulated during fertilization and the increase in NO3- indicated that excessive use of NO3- had a negative effect on the E. scandens seedlings. The order of accumulating nitrogen content was leaves > roots > stems. The highest N accumulation occurred in the aboveground parts under the 0 NO3-: 100 NH4+ treatment, whereas the highest N accumulation occurred in the underground parts under the 50 NO3-: 50 NH4+ treatment. Substrate pH increased at the end of fertilization (day 175) compared with the middle stage (day 75), while total nitrogen, ammonium, and nitrate were highly significantly different among the treatments. Total nitrogen and NH4+ content were the highest under the 0 NO3-: 100 NH4+ treatment, while NO3- content was the highest under the 100 NO3-: 0 NH4+ treatment. In conclusion, 12-month-old E. scandens seedlings grew best, and had better physiological conditions in NH4+ than NO3-. The 0 NO3-:100 NH4+ treatment (ammonium chloride 3.82 g/plant) resulted in the best growth and physiological conditions. Most of the growth and physiological indexes were inhibited with the increase in nitrate.
Topics: Nitrates; Ammonium Compounds; Chlorophyll; Seedlings; Nitrogen; Proline; Sugars; Plant Roots
PubMed: 37540657
DOI: 10.1371/journal.pone.0289659