Clinical resistance to amikacin and other aminoglycosides is usually due to enzymatic acetylation of the antimicrobial molecule. A ubiquitous resistance enzyme among Gram-negatives is the aminoglycoside 6'-N-acetyltransferase type Ib [AAC(6')-Ib], which catalyzes acetylation using acetyl-CoA as donor substrate. Therapies that combine the antibiotic and an inhibitor of the inactivation reaction could be an alternative to treat infections caused by resistant bacteria. We had previously observed that metal ions such as Zn2+ or Cu2+ in complex with ionophores interfere with the AAC(6')-Ib-mediated inactivation of aminoglycosides and reduced resistance to susceptibility levels. Ag1+ recently attracted attention as a potentiator of aminoglycosides' action by mechanisms still in discussion. We found that silver acetate is also a robust inhibitor of the enzymatic acetylation mediated by AAC(6')-Ib in vitro. This action seems to be independent of other mechanisms, like increased production of reactive oxygen species and enhanced membrane permeability, proposed to explain the potentiation of the antibiotic effect by silver ions. The addition of this compound to aac(6')-Ib harboring Acinetobacter baumannii and Escherichia coli cultures resulted in a dramatic reduction of the resistance levels. Time-kill assays showed that the combination of silver acetate and amikacin was bactericidal and exhibited low cytotoxicity to HEK293 cells.

Sexually transmitted infections (STIs) such as Gonorrhea is associated with serious morbidity and mortality rates in the world considering the multiple virulence factors possessed. The disease is manifested as salpingitis, pelvic inflammatory disease (PID), and bacteremia and is controlled by macrophages, dendritic cells, neutrophils, T cells, epithelial cells and cytokines. Dihydroliponamide acetyltransferase, a component of the mitochondrial pyruvate complex can be used as immunogenic target. Recent changes in the strain allowed the bacteria to acquire resistance against antibiotics.Vaccination remains an alternative to prevention against the disease. This study predicts an effective epitope-based vaccine against dihydrolipoamide acetyltransferase of Neisseria Gonorrhea using immunoinformatics approaches. Sequences retrieved from NCBI were passed on several prediction tests to analyze for possible B-cell, T-cell MHC class I epitopes and class II. Two epitopes showed high binding affinity for B-cells, while thirteen epitopes showed high binding affinity for MHCI and forty-five for MHCII. A population coverage of 100% for combined MHC I and II dictates the huge number of individuals who will benefit from formulating the vaccine. We recommend invivo and invitro studies to prove our prediction results.

The present study examined differences in operant responses in adult male and female rats during distinct phases of addiction. Males and females demonstrated escalation in methamphetamine (0.05 mg/kg, i.v.) intake with females showing enhanced latency to escalate, and bingeing. Following protracted abstinence, females show reduced responses during extinction, and have greater latency to extinguish compared with males, indicating reduced craving. Females demonstrated lower context-driven reinstatement compared to males, indicating that females have less motivational significance to the context associated with methamphetamine. Whole-cell patch-clamp recordings on dentate gyrus (DG) granule cell neurons (GCNs) were performed in acute brain slices from controls and methamphetamine experienced male and female rats and neuronal excitability were evaluated from GCNs. Reinstatement of methamphetamine seeking reduced spiking in males, and increased spiking in females compared to controls, demonstrating distinct neuroadaptations in intrinsic excitability of GCNs in males and females. Reduced excitability of GCNs in males were associated with enhanced levels of neural progenitor cells, expression of plasticity-related proteins including CaMKII and choline acetyltransferase in the DG. Enhanced excitability in females were associated with increased GluN2A/2B ratio, indicating changes in postsynaptic GluN subunit composition in the DG. Altered intrinsic excitability of GCNs were associated with reduced mossy fiber terminals in the hilus and pyramidal projections, demonstrating compromised neuroplasticity in the DG in both sexes. The alterations in excitability, plasticity-related proteins and mossy fiber density were correlated with enhanced activation of microglial cells in the hilus, indicating neuroimmune responses in both sexes. Together, the present results indicate sexually dimorphic adaptive biochemical changes in excitatory neurotransmitter systems in the DG and highlight the importance of including sex as a biological variable in exploring neuroplasticity and neuroimmune changes that predict enhanced relapse to methamphetamine-seeking behaviors.

Background: In the domestic pig, neural and non-neuronal cholinergic systems in the gallbladder and extrahepatic bile ducts need a detailed morphological study to identify the type and localization of their structural components. We aimed to quantitatively analyze biliary cholinergic ganglia and nerves as well as non-neuronal cholinergic cells; Methods: Immunohistochemical detection of choline acetyltransferase expression was performed to define cholinergic nerve and non-neuronal structures in gallbladder and extrahepatic bile ducts; Results: The number and dimensions of cholinergic ganglia, perikaryons and nerves forming ganglionic nerve plexuses in the propria, muscular and subserosal layers was estimated. The immunoexpression of choline acetyltransferase in biliary glandular cells and mast cells was also detected and analyzed. Conclusions: Qualitative and quantitative analysis of choline acetyltransferase positive nerves, ganglionic and non-ganglionic nerve plexuses of acetylcholine supplemented the morphological knowledge of the cholinergic innervation of the extrahepatic biliary pathways and non-neuronal sources: glandular cholinergic cells and cholinergic-type mast cells. Original data of the number and dimensions of intramural nerves, mast cells, ganglia and ganglion perikaryons could be used as reference values in the diagnosis of neuropathological processes in biliary pathways. Clarifying the precise mechanisms of gallbladder smooth muscle contractility will contribute to the improvement of therapeutic strategies to prevent biliary stasis and biliary disorders.

B lymphocyte development has two DNA recombination processes: V(D)J recombination of the immunoglobulin (Igh) gene variable region and class switching of the Igh constant regions from IgM to IgG, IgA, or IgE. V(D)J recombination is required for successful maturation of B cells from pro-B to pre-B to immature-B and then to mature B cells in the bone marrow. CSR occurs outside of the bone marrow when mature B cells migrate to peripheral lymphoid organs, such as spleen and lymph nodes. Both V(D)J recombination and CSR depend on an “open chromatin” state that makes DNA accessible to specific enzymes, recombination activating gene (RAG), and activation-induced cytidine deaminase (AID). Acetyltransferases GCN5 and PCAF possess redundant functions acetylating histone H3 lysine 9 (H3K9). Here, we generated a mouse model that lacks both GCN5 and PCAF in B cells. We found that double-deficient mice possess low levels of mature B cells in the bone marrow and peripheral organs, an accumulation of pro-B cells in bone marrow, and reduced CSR levels. We conclude that both GCN5 and PCAF are required for B cell development in vivo.

The aminoglycoside 6′-N-acetyltransferase type Ib [AAC(6′)-Ib] is a common cause of resistance to amikacin and other aminoglycosides in Gram-negatives. Utilization of mixture-based combinatorial libraries and application of the positional scanning strategy identified an inhibitor of AAC(6′)-Ib. This inhibitor’s chemical structure consists of a pyrrolidine pentamine scaffold substituted at four locations (R1, R3, R4, and R5). The substituents are two S-phenyl (R1 and R4), an S-hydroxymethyl (R3), and a 3-phenylbutyl (R5) groups. Another location, R2, does not have a substitution, but it is named because its stereochemistry was modified in some compounds utilized in this study. Structure-activity relationship (SAR) analysis using derivatives with different functionalities, modified stereochemistry, and truncations were carried out by assessing the effect of the addition of each compound at 8 µM to 16 µg/ml amikacin-containing media and performing checkerboard assays varying the concentrations of the inhibitor analogs and the antibiotic. The results showed that: 1) the aromatic functionalities at R1 and R4 are essential, but the stereochemistry is essential only at R4, 2) the stereochemical conformation at R2 is critical, 3) the hydroxyl moiety at R3 as well as stereoconformation are required for full inhibitory activity, 4) the phenyl functionality at R5 is not essential and can be replaced by aliphatic groups, 5) the location of the phenyl group on the butyl carbon chain at R5 is not essential, 6) the length of the aliphatic chain at R5 is not critical, 7) all truncations of the scaffold resulted in inactive compounds. Molecular docking revealed that all compounds preferentially bind to the kanamycin C binding cavity, and binding affinity correlates with the experimental data for most of the compounds evaluated. The SAR results in this study will serve as the basis for the design of new analogs in an effort to improve their ability to induce phenotypic conversion to susceptibility in amikacin-resistant pathogens.

The conserved MYST proteins form the largest family of histone acetyltransferases (HATs) that acetylate lysines within the N-terminal tails of histone, enabling active gene transcription. Here, we have investigated the biological and regulatory functions of the MYST family HAT Sas3 in the opportunistic human pathogenic fungus Aspergillus fumigatus using a series of genetic, biochemical, pathogenic, and transcriptomic analyses. The deletion of sas3 results in drastically reduced colony growth, asexual development, spore germination, response to stresses, and the fungal virulence. Genome-wide expression analyses have revealed that the sas3 mutant showed 2,402 significant differentially expressed genes; 1,147 up-regulated and 1,255 down-regulated. The representative up-regulated gene resulting from sas3 is hacA predicted to encode a bZIP transcription factor, whereas the UV-endonuclease UVE-1 was significantly down-regulated by sas3. Furthermore, our Western blot analyses suggest that Sas3 likely catalyzes acetylation of H3K9, K3K14, and H3K29 in A. fumigatus. In conclusion, Sas3 is associated with diverse biological processes and can be a potential target for controlling pathogenic fungi.

Autism Spectrum disorder (ASD) and intellectual disability (ID) are the most frequent develop-mental disorders with a prevalence between 3% and 5% of the population. In addition, both ASD and ID can be found in the same patient. Mutations in several genes involved in the epigenetic regulation of gene expression have been linked to different ID associated with ASD features including alterations of the ly-sine-acetyltransferase 6A (KAT6A) gene in KAT6A syndrome. KAT6A enzyme participates in a wide range of critical cellular functions such as chromatin remodeling, gene expression, protein synthesis, cell metabolism, and replication. In this manuscript, we examined the pathophysiolog-ical alterations in fibroblasts derived from three patients harboring KAT6A mutations. We ad-dressed survival in stress medium, histone acetylation, protein expression patterns and tran-scriptome analysis as well as cell bioenergetics. In addition, we evaluated the therapeutic effec-tiveness of epigenetic modulators and mitochondrial boosting agents such as pantothenate and L-carnitine in correcting the mutant phenotype. Pantothenate and L-carnitine treatment increased histone acetylation and corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly correct the mutant phe-notype in cellular models of KAT6A syndrome.

Several studies suggests that ghrelin (GHRL) has neurobiological effects that extend beyond control of food intake. Our previous results confirmed that GHRL modulates the secretory activity of the pineal gland (PG) through nocturnal melatonin (MEL) secretion in sheep, the seasonally reproductive animals. Here we investigated the effects of GHRL (10 ng/ml) on the expression of enzymes limiting synthesis of MEL, including tryptophan 5-hydroxylase 1 (TPH1), serotonin N-acetyltransferase (AA-NAT) and its phosphorylated form p31T-AA-NAT in sheep PG explants (n = 72) during the 4-hour incubation in a gas-liquid interface, at a short (SD) and long (LD) photoperiods. After each hour of incubation selected explants were frozen in liquid nitrogen and stored at -80°C for subsequent analysis (real-time PCR, western-blotting, ELISA). Results show that GHRL regulates nightly MEL secretion in a TPH1-independent manner. The factor modulating GHRL activity was photoperiod. During SD photoperiod GHRL significantly reduced the expression of p31T-AA-NAT, AA-NAT and inhibited MEL secretion from PG explants. Whereas, during LD photoperiod no effect of GHRL on MEL secretion and expression of examined enzymes was noted. Studies indicate that GHRL directly affects PG under in vitro conditions and causes MEL secretion in animals which exhibit seasonality in reproductive and metabolic processes.

Ageing may be characterized by progressive loss of cognitive function as well as decrease in physical activities, in addition to change in appearance. Previously, we reported that intracerebroventricular transplantation of a human neural stem cell (NSC) line (F3) over-expressing choline acetyltransferase (F3.ChAT) gene, an enzyme responsible for acetylcholine synthesis, markedly improved cognitive function and physical activity of aged animals by enhancing acetylcholine and growth factors (GFs) and neurotrophic factors (NFs). In the present study, 10-month-old F344 rats were intravenously transplanted with F3 or F3.ChAT NSCs (1 x 106 cells) once a month to 21st month of age when the cumulative mortality reached 20%, and physical activity and learning/memory function were investigated, in addition to the analyses of brain acetylcholine concentration, and cholinergic and dopaminergic system restoration. Neuroprotective and neuroregenerative activities of stem cells were also confirmed by analyzing oxidative damages, neuronal skeletal protein, angiogenesis, brain and muscle weights, and proliferating host stem cells. Stem cells markedly improved both the cognitive (passive avoidance and water-maze performances) and physical (locomotor and rota-rod activities) functions, in parallel with the elevation of acetylcholine levels in cerebrospinal fluid and in muscles, in which F3.ChAT cells were superior to F3 parental cells. Stem cell transplantation down-regulated CCL11, leading to restoration of microtubule-associated protein 2 as well as functional markers of cholinergic and dopaminergic systems, and preserved brain and muscular capillaries, recovering muscle mass. In addition, stem cells enhanced antioxidative capacity, attenuating oxidative damage of multiple organs including muscles and the brain. The results indicate that NSCs over-expressing ChAT gene improve cognitive function and physical activity of ageing animals by protecting and recovering functions of multiple organs including cholinergic and dopaminergic systems as well as muscles from oxidative injuries through secretion of acetylcholine and GFs/NFs, increased antioxidant elements, and enhanced blood flow.

Plazomicin is a recently U.S. Food and Drug Administration (FDA)-approved semisynthetic aminoglycoside. Its structure consists of a sisomicin scaffold modified by adding a 2(S)-hydroxy aminobutyryl group at the N1 position and a hydroxyethyl substituent at the 6′ position. These substitutions produced a molecule refractory to most aminoglycoside-modifying enzymes. The main enzyme within this group that recognizes plazomicin as substrate is the aminoglycoside 2′-N-acetyltransferase type Ia [AAC(2′)-Ia], which reduces the antibiotic’s potency. Designing formulations that combine an antimicrobial with an inhibitor of resistance is a recognized strategy to extend the useful life of existing antibiotics. We have recently found that several metal ions inhibit acetylation of numerous aminoglycosides catalyzed by the aminoglycoside 6′-N-acetyltransferase type Ib [AAC(6′)-Ib]. In particular, Ag1+, which also enhances the effect of aminoglycosides by other mechanisms, is very effective in interfering with AAC(6′)-Ib-mediated resistance to amikacin. Here we report that silver acetate is a potent inhibitor of AAC(2′)-Ia-mediated acetylation of plazomicin in vitro, and it reduces resistance levels of Escherichia coli carrying aac(2′)-Ia. The resistance reversion assays produced equivalent results when the structural gene was expressed under the control of the natural or the blaTEM-1 promoters. The antibiotic effect of plazomicin in combination with silver was bactericidal, and the mix did not show significant toxicity to human embryonic kidney 293 (HEK293) cells.