N-acetyltransferase Gene Research Articles

Variants in the N-acetyltranferase 2 gene, acetylator phenotypes and their association with tuberculosis: Findings in Peruvian patients

BackgroundTuberculosis (TB) is a highly prevalent chronic infectious disease in developing countries, with Peru being one of the most affected countries in the world. The variants of the N-acetyltransferase 2 (NAT2) gene are related to xenobiotic metabolism and have potential usefulness in TB studies. AimTo determine whether NAT2 gene variants and acetylator phenotypes are associated with active TB in Peruvian patients. MethodsThis study included cases (patients with TB) and controls (population-based data). First, DNA isolation and the rs1799929, rs1799930, and rs1799931 variants of the NAT2 gene were identified using sequencing methods. Subsequently, the acetylator phenotypes, namely slow (SA), intermediate (IA), and rapid acetylation (RA), were also analyzed. ResultsThe comparison of the frequencies of the rs1799931 variant in the cases and controls revealed significant differences. Risk factors were found for both the A allele (p = 0.00; odds ratio [OR] = 3.04, 95 % confidence interval [CI]: 1.88–4.9) and AG genotype (p = 0.00; OR = 5.94, 95 % CI: 3.17–11.09). In addition, the non-rapid acetylator phenotype (SA + IA) was also found to be a risk factor (p = 0.016; OR = 3.16, 95 % CI: 1.29–7.72). ConclusionThe A allele, GA heterozygous genotype of the rs1799931 variant of the NAT2 gene, and SA + IA acetylator phenotype showed an association with increased risk for the development of TB. In addition to xenobiotic metabolism, other metabolic and immunological functions of NAT2 have also been postulated to confer susceptibility to TB in the Peruvian population owing to its characteristic high Native American component.

Identification and functional analysis of two serotonin N-acetyltransferase genes in maize and their transcriptional response to abiotic stresses.

Melatonin, a tryptophan-derived indoleamine metabolite with important roles in plant growth and defense, has recently been regarded as a new plant hormone. Maize is one of the most important cereal crops in the world. Although the melatonin receptor gene, ZmPMTR1, has already been identified, the genetic basis of melatonin biosynthesis in maize has still not been elucidated. Serotonin N-acetyltransferase (SNAT) is the enzyme that converts serotonin to N-acetylserotonin (NAS) or 5-methoxytryptamine (5MT) to melatonin in Arabidopsis and rice, but no SNAT encoding gene has been identified yet in maize. The bioinformatics analysis was used to identify maize SNAT genes and the enzyme activity of the recombinant proteins was determined through in vitro assay. The expression levels of ZmSNAT1 and ZmSNAT3 under drought and heat stresses were revealed by public RNA-seq datasets and qRT-PCR analysis. We first identified three maize SNAT genes, ZmSNAT1, ZmSNAT2, and ZmSNAT3, through bioinformatics analysis, and demonstrated that ZmSNAT2 was present in only eight of the 26 cultivars analyzed. We then determined the enzyme activity of ZmSNAT1 and ZmSNAT3 using their recombinant proteins through in vitro assay. The results showed that both ZmSNAT1 and ZmSNAT3 could convert serotonin to NAS and 5-MT to melatonin. Recombinant ZmSNAT1 catalyzed serotonin into NAS with a higher catalytic activity (K m, 8.6 mM; V max, 4050 pmol/min/mg protein) than ZmSNAT3 (K m, 11.51 mM; V max, 142 pmol/min/mg protein). We further demonstrated that the 228th amino acid Tyr (Y228) was essential for the enzymatic activity of ZmSNAT1. Finally, we revealed that the expression of ZmSNAT1 and ZmSNAT3 varied among different maize cultivars and different tissues of a plant, and was responsive to drought and heat stresses. In summary, the present study identified and characterized the first two functional SNAT genes in maize, laying the foundation for further research on melatonin biosynthesis and its regulatory role in plant growth and response to abiotic stresses.

Knockdown of the glucosamine-6-phosphate N-acetyltransferase gene by RNA interference enhances the virulence of entomopathogenic fungi against rice leaffolder Cnaphalocrocis medinalis

Insect cuticle acts as a first line of defense and a physical protective barrier against entomopathogens. Chitin biosynthesis pathway plays a crucial role in chitin formation in the cuticle of insects. Glucosamine-6-phosphate N-acetyltransferase (GNA) is a key enzyme in insect chitin biosynthesis that regulate the chitin formation. However, how GNA-mediated cuticle metabolism influences virulence of entomopathogenic fungi is still unknown. In this study, CmGNA gene was cloned and characterized from the rice leaffolder Cnaphalocrocis medinalis. The CmGNA contains an open read frame (ORF) 600 nucleotides, encoding 199 amino acids with an isoelectric point of 8.65 and a molecular weight of 22.30 kDa. The expression profile showed that CmGNA was highly expressed in 4th instar larvae and in the cuticle. Here, we also reported the impact of CmGNA gene and entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, on expression pattern of chitin biosynthesis genes, feeding behavior, survival rate and average body weight of infected larvae, phenotypic deformities, rate of pupation, and adult emergence. Our results showed that knockdown of CmGNA and application of M. anisopliae and B. bassiana three days after RNA interference (RNAi) significantly decreased the expression of CmGNA and other associated genes, reduced feeding efficiency and survival rate, and caused loss of average body weight, less rate of pupation and adult emergence of infected larvae. Knockdown of CmGNA gene also increased the lethality of larvae caused by M. anisopliae and B. bassiana and resulted in significantly phenotypic deformities of infected larvae. Our findings illustrated that RNAi-mediated CmGNA knockdown disturbed the chitin synthesis genes that led to enhancing the virulence of M. anisopliae and B. bassiana, which can provide us new insights to develop novel biocontrol strategies against C. medinalis.

N-acetyltransferase Gene Variants Involved in Pediatric Idiosyncratic Drug-Induced Liver Injury.

Idiosyncratic drug-induced liver injury (DILI) is a complex multifactorial disease in which the toxic potential of the drug, together with genetic and acquired factors and deficiencies in adaptive processes, which limit the extent of damage, may determine susceptibility and make individuals unique in their development of hepatotoxicity. In our study, we sequenced the exomes of 43 pediatric patients diagnosed with DILI to identify important gene variations associated with this pathology. The result showed the presence of two variations in the NAT2 gene: c.590G>A (p.Arg197Gln) and c.341T>C (p.Ile114Thr). These variations could be found separately or together in 41 of the 43 patients studied. The presence of these variations as a risk factor for DILI could confirm the importance of the acetylation pathway in drug metabolism.

Biodegradation of aniline blue dye by salt-tolerant Bacillus thuringiensis DHC4 isolated from soil-feeding termite guts

The existence of aniline blue in aquatic environments poses a large threat to aquatic organisms. Microbial degradation of aniline blue has been frequently used in remediation because of its effectiveness, low cost, and environmental friendliness. However, the mechanisms by which the dye can be biodegraded are not well understood. In this study, Bacillus thuringiensis DHC4 was isolated from the gut of a soil-feeding termite, and its ability to degrade aniline blue was investigated. The results showed that DHC4 was highly resistant to both aniline blue and salt, with the decolorization rate reaching 78% and 67% after 96 h of incubation at initial dye concentrations of 1 g/L and 7% salinity, respectively. Aniline blue degradation products were identified based on UV–vis, FTIR, and GC–MS analyses, and genome analysis confirmed that DHC4 contained many potential dye-degrading genes. Transcriptome analysis revealed significant up-regulation of methyltransferase, nitroreductase, arylamine N-acetyltransferase and oxidoreductase genes on exposure to aniline blue, indicating their active role in its biodegradation. A new degradation pathway of aniline blue by DHC4 is proposed, based on analysis of metabolites and differentially expressed genes. This mechanism involves cleavage of aniline blue by oxidoreductases into mono- and diphenyl ring molecules, followed by further methylation and alkylation through methyltransferases. The phytotoxicity results showed that aniline blue was degraded by DHC4 into less toxic metabolites. These results provide new insights into the mechanism of biodegradation of aniline blue by microorganisms.

Pharmacogenetic Study of Drugs Affecting Mycobacterium tuberculosis.

Pharmacogenetic research has led to significant progress in understanding how genetic factors influence drug response in tuberculosis (TB) treatment. One ongoing challenge is the variable occurrence of adverse drug reactions in some TB patients. Previous studies have indicated that genetic variations in the N-acetyltransferase 2 (NAT2) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) genes can impact the blood concentrations of the first-line anti-TB drugs isoniazid (INH) and rifampicin (RIF), respectively. This study aimed to investigate the influence of pharmacogenetic markers in the NAT2 and SLCO1B1 genes on TB treatment outcomes using whole-exome sequencing (WES) analysis. DNA samples were collected from 30 healthy Iranian adults aged 18-40 years. The allelic frequencies of single-nucleotide polymorphisms (SNPs) in the NAT2 and SLCO1B1 genes were determined through WES. Seven frequent SNPs were identified in the NAT2 gene (rs1041983, rs1801280, rs1799929, rs1799930, rs1208, rs1799931, rs2552), along with 16 frequent SNPs in the SLCO1B1 gene (rs2306283, rs11045818, rs11045819, rs4149056, rs4149057, rs2291075, rs201722521, rs11045852, rs11045854, rs756393362, rs11045859, rs74064211, rs201556175, rs34671512, rs71581985, rs4149085). Genetic variations in NAT2 and SLCO1B1 can affect the metabolism of INH and RIF, respectively. A better understanding of the pharmacogenetic profile in the study population may facilitate the design of more personalized and effective TB treatment strategies. Further research is needed to directly correlate these genetic markers with clinical outcomes in TB patients.

NAT2 Gene Variants as a Provocative Factor for the Severe Course of COVID-19 Pneumonia in Ukrainian Patients

Background: Previous studies indicate a close relationship between the severity of COVID-19 and oxidative stress. N-acetyltransferase 2 (NAT2) is an enzyme that metabolizes a wide range of xenobiotics and plays an important role in the regulation of reactive oxygen species, consequently contributing to the development of oxidative stress. Aim: To determine the impact of NAT2 gene variants on the risk of developing and the progression of severe COVID-19-associated pneumonia in patients from the Poltava region of Ukraine. Methods: The study included 117 patients who were diagnosed with severe COVID-19 pneumonia and received treatment in the intensive care unit. The NAT2 gene variants were identified through the PCR-RFLP method. Results: The presence of the AA genotype of the A803G variant in patients with severe COVID-19 pneumonia is associated with an almost 3-fold reduction in the risk of lethal outcomes. The presence of the TT genotype of the C481T variant was associated with the need for artificial lung ventilation. Patients in the study group with a heterozygous GA genotype of the G590A variant demonstrated a notable rise in the risk of developing systemic inflammatory response syndrome and acute respiratory distress syndrome, with a nearly 2.5-fold and 3-fold increase, respectively. The G857A variant was not associated with the risk of developing the above-- mentioned complications in the examined patients. Conclusion: The obtained results suggested that the NAT2 gene variants might influence the incidence, course, and adverse consequences of COVID-19.

Towards pharmacogenomics-guided tuberculosis (TB) therapy: N-acetyltransferase-2 genotypes among TB-infected Kenyans of mixed ethnicity

BackgroundThough persons of African descent have one of the widest genetic variability, genetic polymorphisms of drug-metabolising enzymes such as N-Acetyltransferase-2 (NAT2) are understudied. This study aimed to identify prevalent NAT2 single nucleotide polymorphisms (SNPs) and infer their potential effects on enzyme function among Kenyan volunteers with tuberculosis (TB) infection. Genotypic distribution at each SNP and non-random association of alleles were evaluated by testing for Hardy-Weinberg Equilibrium (HWE) and Linkage Disequilibrium (LD).MethodsWe isolated genomic DNA from cryopreserved Peripheral Blood Mononuclear Cells of 79 volunteers. We amplified the protein-coding region of the NAT2 gene by polymerase chain reaction (PCR) and sequenced PCR products using the Sanger sequencing method. Sequencing reads were mapped and aligned to the NAT2 reference using the Geneious software (Auckland, New Zealand). Statistical analyses were performed using RStudio version 4.3.2 (2023.09.1 + 494).ResultsThe most frequent haplotype was the wild type NAT2*4 (37%). Five genetic variants: 282C > T (NAT2*13), 341 T > C (NAT2*5), 803A > G (NAT2*12), 590G > A (NAT2*6) and 481C > T (NAT2*11) were observed with allele frequencies of 29%, 18%, 6%, 6%, and 4% respectively. According to the bimodal distribution of acetylation activity, the predicted phenotype was 76% rapid (mainly consisting of the wildtype NAT2*4 and the NAT2*13A variant). A higher proportion of rapid acetylators were female, 72% vs 28% male (p = 0.022, odds ratio [OR] 3.48, 95% confidence interval [CI] 1.21 to 10.48). All variants were in HWE. NAT2 341 T > C was in strong complete LD with the 590G > A variant (D′ = 1.0, r2 = − 0.39) but not complete LD with the 282C > T variant (D′ = 0.94, r2 = − 0.54).ConclusionThe rapid acetylation haplotypes predominated. Despite the LD observed, none of the SNPs could be termed tag SNP. This study adds to the genetic characterisation data of African populations at NAT2, which may be useful for developing relevant pharmacogenomic tools for TB therapy. To support optimised, pharmacogenomics-guided TB therapy, we recommend genotype-phenotype studies, including studies designed to explore gender-associated differences.

Association of the cytochrome P450 and arylamine N-acetyltransferase gene polymorphisms with the incidence of head and neck cancer in Polish population.

Head and neck cancer (HNC) is one of the most common cancers. Most exogenous HNC is head and neck squamous cell carcinomas. Scientists are striving to develop diagnostic tests that will allow the prognosis of HNC. The aim of the study was to determine the risk of HNC. The research concerned changes caused by polymorphisms in genes encoding proteins responsible for the metabolism of xenobiotics. In group of 280 patients with HNC, the occurrence of polymorphic variants in NAT1(rs72554606), NAT2(rs1799930), CYP1A(rs1799814), CYP2D(rs3892097) were studied with TaqMan technique. The control group consisted of 260 cancer free people. The TNM scale was analyzed. Gene interactions of genotyped polymorphisms were investigated. The effects of smoking and alcohol consumption on HNC were assessed. The results indicated an increased risk of HNC in NAT1 polymorphisms in the GC genotype (OR = 1.772, 95% CI: 1.184-2.651, p = 0.005) and NAT2 polymorphism in the GA genotype (OR = 1.506, 95% CI: 1.023-2.216, p = 0.037). The protective phenomenon in the CYP1A polymorphism the GT genotype (OR = 0.587, 95% CI: 0.381-0.903, p = 0.015) and the TT genotype (OR = 0.268, 95% CI: 0.159-0.452, p = 0.001). The coexistence of GA-GC polymorphisms (OR = 2.687, 95% CI: 1.387-5.205, p = 0.003) in NAT2-NAT1 genes increases the risk of HNC. Risk-reducing effect in the polymorphism GG-GT (OR = 0.340, 95% CI: 0.149-0.800, p = 0.011), GG-TT (OR = 0.077, 95% CI: 0.028-0.215, p < 0.0001), GA-TT (OR = 0.250, 95% CI: 0.100-0.622, p = 0.002), AA-GT (OR = 0.276, 95% CI: 0.112-0.676, p = 0.002) in NAT2-CYP1A genes. In the CYP2D-CYP1A genes in the polymorphisms CT-CC (OR = 0.338, 95% CI: 0.132-0.870, p = 0.020), TT-GG (OR = 0.100, 95% CI: 0.027-0.359, p = 0.001), TT-GC (OR = 0.190, 95% CI: 0.072-0.502, p = 0.0004), TT-CC (OR = 0.305, 95% CI: 0.107-0.868, p = 0.024). Correlation was noted between cigarette smoking and HNC (OR = 7.297, 95% CI: 4.989-10.674, p < 0.0001) and consuming alcohol (OR = 1.572, 95% CI: 1.003-2.464, p = 0.047). The CYP1A polymorphism shows a protective association with HNC. On the other hand, NAT2, NAT1 polymorphism influence the susceptibility to developing HNC. The coexistence of the NAT2-NAT1 genotypes increases the risk of HNC. In contrast, NAT1-CYP1A and CYP1A-CYP2D reduce this risk. Smoking and alcohol consumption increase the incidence of HNC. Int J Occup Med Environ Health. 2023;36(6):812-24.

Identification and characterization of a novel 6'-N-aminoglycoside acetyltransferase AAC(6')-Va from a clinical isolate of Aeromonas hydrophila.

Aeromonas species have been identified as agents responsible for various diseases in both humans and animals. Multidrug-resistant Aeromonas strains pose a significant public health threat due to their emergence and spread in clinical settings and the environment. The aim of this study was to determine a novel resistance mechanism against aminoglycoside antimicrobials in a clinical isolate. The function of aac(6')-Va was verified by gene cloning and antibiotic susceptibility tests. To explore the in vivo activity of the enzyme, recombinant proteins were expressed, and enzyme kinetics were tested. To determine the molecular background and mechanism of aac(6')-Va, whole-genome sequencing and bioinformatic analysis were performed. The novel aminoglycoside N-acetyltransferase gene aac(6')-Va confers resistance to several aminoglycosides. Among the antimicrobials tested, ribostamycin showed the highest increase (128-fold) in the minimum inhibitory concentration (MIC) compared with the control strains. According to the MIC results of the cloned aac(6')-Va, AAC(6')-Va also showed the highest catalytic efficiency for ribostamycin [kcat/Km ratio = (3.35 ± 0.17) × 104 M-1 s-1]. Sharing the highest amino acid identity of 54.68% with AAC(6')-VaIc, the novel aminoglycoside N-acetyltransferase constituted a new branch of the AAC(6') family due to its different resistance profiles. The gene context of aac(6')-Va and its close relatives was conserved in the genomes of species of the genus Aeromonas. The novel resistance gene aac(6')-Va confers resistance to several aminoglycosides, especially ribostamycin. Our finding of a novel resistance gene in clinical A. hydrophila will help us develop more effective treatments for this pathogen's infections.

Evaluating interactions of polygenic risk scores and NAT2 genotypes with tobacco smoking in bladder cancer risk.

Tobacco smoking is the most important risk factor for bladder cancer. Previous studies have identified the N-acetyltransferase (NAT2) gene in association with bladder cancer risk. The NAT2 gene encodes an enzyme that metabolizes aromatic amines, carcinogens commonly found in tobacco smoke. In our study, we evaluated potential interactions of tobacco smoking with NAT2 genotypes and polygenic risk score (PRS) for bladder cancer, using data from the UK Biobank, a large prospective cohort study. We used Cox proportional hazards models to measure the strength of the association. The PRS was derived using genetic risk variants identified by genome-wide association studies for bladder cancer. With an average of 10.1 years of follow-up of 390 678 eligible participants of European descent, 769 incident bladder cancer cases were identified. Current smokers with a PRS in the highest tertile had a higher risk of developing bladder cancer (HR: 6.45, 95% CI: 4.51-9.24) than current smokers with a PRS in the lowest tertile (HR: 2.41, 95% CI: 1.52-3.84; P for additive interaction = <.001). A similar interaction was found for genetically predicted metabolizing NAT2 phenotype and tobacco smoking where current smokers with the slow NAT2 phenotype had an increased risk of developing bladder cancer (HR: 5.70, 95% CI: 2.64-12.30) than current smokers with the fast NAT2 phenotype (HR: 3.61, 95% CI: 1.14-11.37; P for additive interaction = .100). Our study provides support for considering both genetic and lifestyle risk factors in developing prevention measures for bladder cancer.

Clinical Significance of NAT2 Genetic Variations in Type II Diabetes Mellitus and Lipid Regulation.

N-acetyltransferase 2 (NAT2) enzyme is a Phase II drug-metabolizing enzyme that metabolizes different compounds. Genetic variations in NAT2 can influence the enzyme's activity and potentially lead to the development of certain diseases. This study aimed to investigate the association of NAT2 variants with the risk of Type II diabetes mellitus (T2DM) and the lipid profile among Jordanian patients. We sequenced the whole protein-coding region in NAT2 using Sanger's method among a sample of 45 Jordanian T2DM patients and 50 control subjects. Moreover, we analyzed the lipid profiles of the patients and examined any potential associations with NAT2 variants. This study revealed that the heterozygous NAT2*13 C/T genotype is significantly (P = 0.03) more common among T2DM (44%) than non-T2DM subjects (23.5%). Furthermore, the frequency of homozygous NAT2*13 T/T genotype was found to be significantly higher (P = 0.03) among T2DM patients (26.7%) compared to that of non-T2DM subjects (11%). The heterozygous NAT2*7 G/A genotype was exclusively observed in T2DM patients (11.1%) and absent in the control non-T2DM group. Moreover, among T2DM patients, those with a homozygous NAT2*11 T/T genotype exhibited significantly higher levels of triglycerides (381.50 ± 9.19 ng/dL) with a P value of 0.01 compared to those with heterozygous NAT2*11 C/T (136.23 ± 51.12 ng/dL) or wild-type NAT2*11 C/C (193.65 ± 109.89 ng/dL) genotypes. T2DM patients with homozygous NAT2*12 G/G genotype had a significantly (P = 0.04) higher triglyceride levels (275.67 ± 183.42 ng/dL) than the heterozygous NAT2*12 A/G (140.02 ± 49.53 ng/dL) and the wild NAT2*12 A/A (193.65 ± 109.89 ng/dL). The finding in this study suggests that the NAT2 gene is a potential biomarker for the development of T2DM and changes in triglyceride levels among Jordanians. However, it is important to note that our sample size was limited; therefore, further clinical studies with a larger cohort are necessary to validate these findings.

In maize, co-expression of GAT and GR79-EPSPS provides high glyphosate resistance, along with low glyphosate residues

Herbicide tolerance has been the dominant trait introduced during the global commercialization of genetically modified (GM) crops. Herbicide-tolerant crops, especially glyphosate-resistant crops, offer great advantages for weed management; however, despite these benefits, glyphosate-resistant maize (Zea mays L.) has not yet been commercially deployed in China. To develop a new bio-breeding resource for glyphosate-resistant maize, we introduced a codon-optimized glyphosate N-acetyltransferase gene, gat, and the enolpyruvyl-shikimate-3-phosphate synthase gene, gr79-epsps, into the maize variety B104. We selected a genetically stable high glyphosate resistance (GR) transgenic event, designated GG2, from the transgenic maize population through screening with high doses of glyphosate. A molecular analysis demonstrated that single copy of gat and gr79-epsps were integrated into the maize genome, and these two genes were stably transcribed and translated. Field trials showed that the transgenic event GG2 could tolerate 9000 g acid equivalent (a.e.) glyphosate per ha with no effect on phenotype or yield. A gas chromatography-mass spectrometry (GC–MS) analysis revealed that, shortly after glyphosate application, the glyphosate (PMG) and aminomethylphosphonic acid (AMPA) residues in GG2 leaves decreased by more than 90% compared to their levels in HGK60 transgenic plants, which only harbored the epsps gene. Additionally, PMG and its metabolic residues (AMPA and N-acetyl-PMG) were not detected in the silage or seeds of GG2, even when far more than the recommended agricultural dose of glyphosate was applied. The co-expression of gat and gr79-epsps, therefore, confers GG2 with high GR and a low risk of herbicide residue accumulation, making this germplasm a valuable GR event in herbicide-tolerant maize breeding.

TaqMan Genotyping Assay Method for Single Nucleotide Polymorphisms (SNPs) detection in promoter region of N-Acetyltransferase 2 (NAT2) gene

The N-acetyltransferase 2 (NAT2) polymorphism in coding region has been studies intensively. However, there are limited studies for promoter region of NAT2 gene. Several reported study showed that the promoter region polymorphism of NAT2 gene is genotyped by PCR-sequencing approach. In this paper, we describe TaqMan based assays for the NAT2 polymorphism genotyping in promoter region with following SNP: rs4646243 [T&gt;C], rs4646244 [T&gt;A], rs4646267 [A&gt;G], rs4345600 [A&gt;G], and rs4646246 [A&gt;G]. Our result showed a good separation cluster, trailing cluster and some mix cluster. TaqMan genotyping assay has shown a sensitivity and specificity to detect polymorphism in NAT2 promoter region.

N -acetyltransferase 2 haplotype modifies risks for both dyslipidemia and urinary bladder cancer.

A novel haplotype in N -acetyltransferase 2 ( NAT2 ) composed of seven non-coding variants (rs1495741, rs4921913, rs4921914, rs4921915, rs146812806, rs35246381, and rs35570672) has been linked to dyslipidemia by multiple, independent genome-wide association studies. The haplotype is located approximately 14 kb downstream of NAT2-coding region (ch8:18,272,377-18,272,881; GRCh38/hg38) and represents a non-coding, intergenic haplotype. Interestingly, the same dyslipidemia NAT2 haplotype is also linked to urinary bladder cancer risk. Dyslipidemia risk alleles are associated with rapid acetylator phenotype, whereas bladder cancer risk alleles are associated with slow acetylator, suggesting that the level of systemic NAT2 activity modifies the risk of these pathologies. We speculate that rs1495741 (and its associated haplotype) belongs to a distal regulatory element of human NAT2 gene (e.g., enhancer or silencer), and the genetic variation at the newly discovered haplotype results in a differential level of NAT2 gene expression. Understanding how this NAT2 haplotype contributes to not only urinary bladder cancer but also to dyslipidemia will ultimately help devise strategies to identify and protect susceptible individuals.

Identification and characterization of a phosphinothricin N-acetyltransferase from Enterobacter LSJC7

Phosphinothricin (PPT) is a widely used and non-selective herbicide. PPT-resistance genes, especially PPT N-acetyltransferase genes, have been used in the development of transgenic PPT-resistant crops. However, there are only a limited number of available PPT-resistance genes for use in plant biotechnology. In this study, we found that Enterobacter LSJC7 is highly resistant to PPT and can acetylate PPT to N-acetyl phosphinothricin (Ac-PPT). Furthermore, a novel PPT N-acetyltransferase gene, named LsarsN, was identified from LSJC7. When LsarsN was expressed in E. coli AW3110, it confered resistance to PPT. Ac-PPT was detected in both the culture medium and cells of AW3110 expressing the LsarsN-pET22b plasmid. The purified LsArsN protein also showed strong N-acetylation ability in vitro, and its enzymatic kinetic curve was fitted with the Michaelis-Mentan equation. Compared with wild-type LsArsN, both R72A and R74A mutants showed significantly lower PPT N-acetylation ability. In summary, our results systematically characterized LsArsN with strong ability for PPT N-acetylation, which lays the groundwork for future research into the use of this novel gene, LsarsN, to create PPT-resistant crops.

Production of N-acetylglucosamine from carbon dioxide by engineering Cupriavidus necator H16

The conversion of CO2 into valuable bioactive substances using synthetic biological techniques is a potential approach for mitigating the greenhouse effect. Here, the engineering of C. necator H16 to produce N-acetylglucosamine (GlcNAc) from CO2 is reported. First, GlcNAc importation and intracellular metabolic pathways were disrupted by the deletion of nagF, nagE, nagC, nagA and nagB genes. Second, the GlcNAc-6-phosphate N-acetyltransferase gene (gna1) was screened. A GlcNAc-producing strain was constructed by overexpressing a mutant gna1 from Caenorhabditis elegans. A further increase in GlcNAc production was achieved by disrupting poly(3-hydroxybutyrate) biosynthesis and the Entner–Doudoroff pathways. The maximum GlcNAc titers were 199.9 and 566.3 mg/L for fructose and glycerol, respectively. Finally, the best strain achieved a GlcNAc titer of 75.3 mg/L in autotrophic fermentation. This study demonstrated a conversion of CO2 to GlcNAc, thereby providing a feasible approach for the biosynthesis of various bioactive chemicals from CO2 under normal conditions..

Mucopolysaccharidosis type IIIC in chinese mainland: clinical and molecular characteristics of ten patients and report of six novel variants in the HGSNAT gene.

Mucopolysaccharidosis type IIIC (MPS IIIC; Sanfilippo syndrome C) is a rare lysosomal storage disease caused by mutations in the heparan-α-glucosaminide N-acetyltransferase (HGSNAT) gene, resulting in the accumulation of heparan sulfate. MPS IIIC is characterized by severe neuropsychiatric symptoms and mild somatic symptoms. Our study analyzed the clinical presentation and biochemical characteristics of ten Chinese MPS IIIC patients from eight families. Whole exome sequencing was applied to identify the variants in HGSNAT gene. In one patient with only one mutant allele identified firstly, whole genome sequencing was applied. The pathogenic effect of novel variants was evaluated in silico. The mean age at the onset of clinical symptoms was 4.2 ± 2.5 years old, and the mean age of diagnosis was 7.6 ± 4.5 years old, indicating a delay of diagnosis. The most common onset symptoms were speech deterioration, and the most frequent presenting symptoms are speech deterioration, mental deterioration, hyperactivity and hepatomegaly, sequentially. All mutant alleles of 10 patients have been identified. There were eleven different HGSNAT variants, and the most common one was a previously reported variant c.493 + 1G > A. There were six novel variants, p.R124T, p.G290A, p.G426E, c.743 + 101_743 + 102delTT, c.851 + 171T > A and p.V582Yfs*18 in our cohort. Extraordinarily, two deep intron variants were identified in our cohort, with the variant c.851 + 171T > A identified by whole genome sequencing. This study analyzed the clinical, biochemical, and genetic characteristics of ten Chinese MPS IIIC patients, which would assist in the early diagnosis and genetic counselling of MPS IIIC.

Allelic Frequencies of Single Nucleotide Polymorphisms (SNPs) in the N-acetyltransferase 2 (NAT2) Gene of Filipinos

Objectives. The present study aims to determine the frequency of occurrence of NAT2*4, NAT2*5A, NAT2*6B, NAT2*7A and NAT2*14A alleles by PCR-RFLP among Filipino volunteers. These alleles correspond to substitutions in the following sites: C341T, G590A, G857A and G191A, respectively, of the NAT2 gene. The presence of specific SNP combination was also used to deduce acetylation status and estimate genotype frequency and describe them in comparison with other populations based on literature.&#x0D; Methods. Genomic DNA from peripheral blood lymphocytes from 129 healthy Filipino volunteers was used to amplify the NAT2 gene segment. The RFLP analysis was done by restricting the expected PCR product with Kpn1, Taq1, BamH1 and Msp1/Al1, respectively, to detect the 4 alleles: NAT2*4, NAT2*5A, NAT2*6B, NAT2*7A and NAT2*14A.&#x0D; Results. The calculated allelic frequencies in Hardy-Weinberg equilibrium of NAT2*5A (C481T), NAT2*6B (G590A), NAT2*7A (G857A) and NAT2*14A (G191A) were 0.058, 0.097, 0.182 and 0.046, respectively. NAT2*4 had an allele frequency of 0.617. Nine genotypes were determined: NAT2*4/*4, NAT2*4/*5A, NAT2*4/*6B, NAT2*4/*7A, NAT2*4/*14A, NAT2*5A/*7A, NAT2*6B/*7A, NAT2*6B/*14A and NAT2*7A/*14A. From these genotypes, acetylator phenotypes were deduced. A trimodal pattern of distribution was established: rapid, intermediate and slow acetylators with the following percentages, 47.3%, 41.1 % and 11.6%. Among the slow acetylator SNPs determined, NAT2*7A was found as the most frequent allele and NAT2*14A was found as the least frequent allele.&#x0D; Conclusion. The study showed the mutation profile and observed genotypic similarities and differences of Filipinos with other Asian populations and Americans and other Caucasians based on literature. The results also suggest a trimodal pattern of distribution of acetylators and lesser number of slow acetylators among Filipino populations, a characteristic similar to other Asian populations but significantly different from Americans and other Caucasians. The occurrence of NAT2*7A and NAT2*14A can be further sequenced to verify the observed genotype.&#x0D;

Discrepancies in rhizobacterial assembly caused by glyphosate application and herbicide-tolerant soybean Co-expressing GAT and EPSPS

There are concerns that the innovation of genetically modified herbicide-tolerant (GMHT) plants, as well as the application of herbicide to such GMHT plants, could have an impact on ecological interactions and unintentionally harm non-targeted organisms. Consequently, we intend to use full-length 16 S rDNA amplicon sequencing to examine changes in the bacterial community in the rhizosphere of GMHT soybean (Z106) harboring 5-enolpyruvylshikimate-3-phosphate synthase and Glyphosate N-acetyltransferase genes and GMHT soybean treated with glyphosate (Z106G). Glyphosate application significantly impacted bacterial alpha diversity (species richness, and Shannon diversity). Permutational multivariate analysis of variance of beta diversity demonstrated that soil compartments and growth stages had a substantial impact on soybean rhizobacterial communities (soil compartments, growth stages, P = 0.001). Community composition revealed that Z106G soils were abundant in Taibaiella and Arthrobacter pascens at maturity, while Chryseobacterium joostei and Stenotrophomonas maltophilia predominated in Z106 soils during flowering. Nitrogen-fixing and phosphate-solubilizing microbes were found in higher proportions in the rhizosphere than in bulk soil, with Sinorhizobium being more abundant in Z106 and Bacillus and Stenotrophomonas being more prevalent in Z106G rhizosphere soils. Collectively, our findings suggest glyphosate application and glyphosate-tolerant soybean as potential regulators of soybean rhizobacterial composition.