Genetic diversity of KPC-2-producing Klebsiella pneumoniae complex from aquatic ecosystems.

During the COVID-19 pandemic, the occurrence of carbapenem-resistant Klebsiella pneumoniae increased in human clinical settings worldwide. Impacted by this increase, international high-risk clones harboring carbapenemase-encoding genes have been circulating in different sources, including the environment. The blaKPC gene is the most commonly disseminated carbapenemase-encoding gene worldwide, whose transmission is carried out by different mobile genetic elements. In this study, blaKPC-2-positive Klebsiella pneumoniae complex strains were isolated from different anthropogenically affected aquatic ecosystems and characterized using phenotypic, molecular, and genomic methods. K. pneumoniae complex strains exhibited multidrug-resistant and extensively drug-resistant profiles, spotlighting the resistance to carbapenems, ceftazidime-avibactam, colistin, and tigecycline, which are recognized as last-line antimicrobial treatment options. Molecular analysis showed the presence of several antimicrobial resistance, virulence, and metal tolerance genes. In-depth analysis showed that the blaKPC-2 gene was associated with three different Tn4401 isoforms (i.e., Tn4401a, Tn4401b, and Tn4401i) and NTEKPC elements. Different plasmid replicons were detected and a conjugative IncN-pST15 plasmid harboring the blaKPC-2 gene associated with Tn4401i was highlighted. K. pneumoniae complex strains belonging to international high-risk (e.g., ST11 and ST340) and unusual clones (e.g., ST323, ST526, and ST4216) previously linked to clinical settings. In this context, some clones were reported for the first time in the environmental sector. Therefore, these findings evidence the occurrence of carbapenemase-producing K. pneumoniae complex strains in aquatic ecosystems and contribute to the monitoring of carbapenem resistance worldwide.

Antisolvent precipitation for the synergistic preparation of ultrafine particles of nobiletin under ultrasonication-homogenization and evaluation of the inhibitory effects of α-glucosidase and porcine pancreatic lipase in vitro.

To further enhance the application of nobiletin (an important active ingredient in Citrus fruits), we used ultrasonic homogenization-assisted antisolvent precipitation to create ultrafine particles of nobiletin (UPN). DMSO was used as the solvent, and deionized water was used as the antisolvent. When ultrasonication (670 W) and homogenization (16000 r/min) were synergistic, the solution concentration was 57 mg/mL, and the minimum particle size of UPN was 521.02 nm. The UPN samples outperformed the RN samples in terms of the inhibition of porcine pancreatic lipase, which was inhibited (by 500 mg/mL) by 68.41 % in the raw sample, 90.34 % in the ultrafine sample, and 83.59 % in the positive control, according to the data. Fourier transform infrared spectroscopy analysis revealed no chemical changes in the samples before or after preparation. However, the crystallinity of the processed ultrafine nobiletin particles decreased. Thus, this work offers significant relevance for applications in the realm of food chemistry and indirectly illustrates the expanded application potential of nobiletin.

Efficient biotransformation of naringenin to naringenin α-glucoside, a novel α-glucosidase inhibitor, by amylosucrase from Deinococcus wulumuquiensis.

Amylosucrase (ASase) efficiently biosynthesizes α-glucoside using flavonoids as acceptor molecules and sucrose as a donor molecule. Here, ASase from Deinococcus wulumuqiensis (DwAS) biosynthesized more naringenin α-glucoside (NαG) with sucrose and naringenin as donor and acceptor molecules, respectively, than other ASases from Deinococcus sp. The biotransformation rate of DwAS to NαG was 21.3% compared to 7.1-16.2% for other ASases. Docking simulations showed that the active site of DwAS was more accessible to naringenin than those of others. The 217th valine in DwAS corresponded to the 221st isoleucine in Deinococcus geothermalis AS (DgAS), and the isoleucine possibly prevented naringenin from accessing the active site. The DwAS-V217I mutant had a significantly lower biosynthetic rate of NαG than DwAS. The kcat/Km value of DwAS with naringenin as the donor was significantly higher than that of DgAS and DwAS-V217I. In addition, NαG inhibited human intestinal α-glucosidase more efficiently than naringenin.

Metabolic engineering of omega-3 long chain polyunsaturated fatty acids in plants using different ∆6- and ∆5-desaturases co-expressed with LPCAT from the marine diatom Phaeodactylum tricornutum.

Continuous research on obtaining an even more efficient production of very long-chain polyunsaturated fatty acids (VLC-PUFAs) in plants remains one of the main challenges of scientists working on plant lipids. Since crops are not able to produce these fatty acids due to the lack of necessary enzymes, genes encoding them must be introduced exogenously from native organisms producing VLC-PUFAs. In this study we reported, in tobacco leaves, the characterization of three distinct ∆6-desaturases from diatom Phaeodactylum tricornutum, fungi Rhizopus stolonifer and microalge Osterococcus tauri and two different ∆5-desaturases from P. tricornutum and single-celled saprotrophic eukaryotes Thraustochytrium sp. The in planta agroinfiltration of essential ∆6-desaturases, ∆6-elongases and ∆5-desaturases allowed for successful introduction of eicosapentaenoic acid (20:5∆5,8,11,14,17) biosynthesis pathway. However, despite the desired, targeted production of ω3-fatty acids we detected the presence of ω6-fatty acids, indicating and confirming previous results that all tested desaturases are not specifically restricted to neither ω3- nor ω6-pathway. Nevertheless, the additional co-expression of acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) from Phaeodactylum tricornutum boosted the proportion of ω3-fatty acids in newly synthesized fatty acid pools. For the most promising genes combinations the EPA content reached at maximum 1.4% of total lipid content and 4.5% of all fatty acids accumulated in the TAG pool. Our results for the first time describe the role of LPCAT enzyme and its effectiveness in alleviating a bottleneck called 'substrate dichotomy' for improving the transgenic production of VLC-PUFAs in plants.

Detection of blaKPC gene among carbapenemase producing Klebsiella pneumoniae isolated from different clinical specimens at tertiary care hospital of Nepal.

BACKGROUND: Klebsiella pneumoniae infections have become a major cause of hospital acquired infection worldwide with the increased rate of acquisition of resistance to antibiotics. Carbapenem resistance mainly among Gram negative is an ongoing problem which causes serious outbreaks dramatically limiting treatment options. This prospective cross-sectional study was designed to detect blaKPC gene from carbapenem resistant K. pneumoniae. MATERIALS AND METHODS: A totally of 1118 different clinical specimens were screened and confirmed for KPC producing K. pneumoniae phenotypically using Meropenem (10 µg) disc. The blaKPC gene was amplified from the isolates of K. pneumoniae to detect the presence of this gene. RESULT: Of the total samples processed, 18.6% (n = 36) were K. pneumoniae and among 36 K. pneumoniae, 61.1% (n = 22/36) were meropenem resistant. This study demonstrated the higher level of MDR 91.7% (n = 33) and KPC production 47.2% (n = 17) among K. pneumoniae isolates. The blaKPC gene was detected in 8.3% (n = 3) of meropenem resistant isolates. CONCLUSION: Since the study demonstrates the higher level of MDR and KPC producing K. pneumoniae isolates that has challenged the use of antimicrobial agents, continuous microbiology, and molecular surveillance to assist early detection and minimize the further dissemination of blaKPC should be initiated. We anticipate that the findings of this study will be useful in understanding the prevalence of KPC-producing K. pneumoniae in Nepal.

Deficiency of neutral cholesterol ester hydrolase 1 (NCEH1) impairs endothelial function in diet-induced diabetic mice.

BACKGROUND: Neutral cholesterol ester hydrolase 1 (NCEH1) plays a critical role in the regulation of cholesterol ester metabolism. Deficiency of NCHE1 accelerated atherosclerotic lesion formation in mice. Nonetheless, the role of NCEH1 in endothelial dysfunction associated with diabetes has not been explored. The present study sought to investigate whether NCEH1 improved endothelial function in diabetes, and the underlying mechanisms were explored. METHODS: The expression and activity of NCEH1 were determined in obese mice with high-fat diet (HFD) feeding, high glucose (HG)-induced mouse aortae or primary endothelial cells (ECs). Endothelium-dependent relaxation (EDR) in aortae response to acetylcholine (Ach) was measured. RESULTS: Results showed that the expression and activity of NCEH1 were lower in HFD-induced mouse aortae, HG-exposed mouse aortae ex vivo, and HG-incubated primary ECs. HG exposure reduced EDR in mouse aortae, which was exaggerated by endothelial-specific deficiency of NCEH1, whereas NCEH1 overexpression restored the impaired EDR. Similar results were observed in HFD mice. Mechanically, NCEH1 ameliorated the disrupted EDR by dissociating endothelial nitric oxide synthase (eNOS) from caveolin-1 (Cav-1), leading to eNOS activation and nitric oxide (NO) release. Moreover, interaction of NCEH1 with the E3 ubiquitin-protein ligase ZNRF1 led to the degradation of Cav-1 through the ubiquitination pathway. Silencing Cav-1 and upregulating ZNRF1 were sufficient to improve EDR of diabetic aortas, while overexpression of Cav-1 and downregulation of ZNRF1 abolished the effects of NCEH1 on endothelial function in diabetes. Thus, NCEH1 preserves endothelial function through increasing NO bioavailability secondary to the disruption of the Cav-1/eNOS complex in the endothelium of diabetic mice, depending on ZNRF1-induced ubiquitination of Cav-1. CONCLUSIONS: NCEH1 may be a promising candidate for the prevention and treatment of vascular complications of diabetes.

Methionine inducing carbohydrate esterase secretion of Trichoderma harzianum enhances the accessibility of substrate glycosidic bonds.

BACKGROUND: The conversion of plant biomass into biochemicals is a promising way to alleviate energy shortage, which depends on efficient microbial saccharification and cellular metabolism. Trichoderma spp. have plentiful CAZymes systems that can utilize all-components of lignocellulose. Acetylation of polysaccharides causes nanostructure densification and hydrophobicity enhancement, which is an obstacle for glycoside hydrolases to hydrolyze glycosidic bonds. The improvement of deacetylation ability can effectively release the potential for polysaccharide degradation. RESULTS: Ammonium sulfate addition facilitated the deacetylation of xylan by inducing the up-regulation of multiple carbohydrate esterases (CE3/CE4/CE15/CE16) of Trichoderma harzianum. Mainly, the pathway of ammonium-sulfate's cellular assimilates inducing up-regulation of the deacetylase gene (Thce3) was revealed. The intracellular metabolite changes were revealed through metabonomic analysis. Whole genome bisulfite sequencing identified a novel differentially methylated region (DMR) that existed in the ThgsfR2 promoter, and the DMR was closely related to lignocellulolytic response. ThGsfR2 was identified as a negative regulatory factor of Thce3, and methylation in ThgsfR2 promoter released the expression of Thce3. The up-regulation of CEs facilitated the substrate deacetylation. CONCLUSION: Ammonium sulfate increased the polysaccharide deacetylation capacity by inducing the up-regulation of multiple carbohydrate esterases of T. harzianum, which removed the spatial barrier of the glycosidic bond and improved hydrophilicity, and ultimately increased the accessibility of glycosidic bond to glycoside hydrolases.

Uridine 5'-Diphospho-glucuronosyltransferase 1A3 (UGT1A3) Prediction of Hepatic Clearance of Organic Anion Transporting Polypeptide 1B3 (OATP1B3) Substrate Telmisartan by Glucuronidation Using In Vitro-In Vivo Extrapolation (IVIVE).

BACKGROUND AND OBJECTIVE: The prediction of pharmacokinetic parameters for drugs metabolised by cytochrome P450 enzymes has been the subject of active research for many years, while the application of in vitro-in vivo extrapolation (IVIVE) techniques for non-cytochrome P450 enzymes has not been thoroughly evaluated. There is still no established quantitative method for predicting hepatic clearance of drugs metabolised by uridine 5'-diphospho-glucuronosyltransferases (UGTs), not to mention those which undergo hepatic uptake. The objective of the study was to predict the human hepatic clearance for telmisartan based on in vitro metabolic stability and hepatic uptake results. METHODS: Telmisartan was examined in liver systems, allowing to estimate intrinsic clearance (CLint, in vitro) based on the substrate disappearance rate with the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) technique. Obtained CLint, in vitro values were corrected for corresponding unbound fractions. Prediction of human hepatic clearance was made from scaled unbound CLint, in vitro data with the use of the well-stirred model, and finally referenced to the literature value of observed clearance in humans, allowing determination of the essential scaling factors. RESULTS: The in vitro scaled CLint, in vitro by UGT1A3 was assessed using three systems, human hepatocytes, liver microsomes, and recombinant enzymes. Obtained values were scaled and hepatic metabolism clearance was predicted, resulting in significant clearance underprediction. Utilization of the extended clearance concept (ECC) and hepatic uptake improved prediction of hepatic metabolism clearance. The scaling factors for hepatocytes, assessing the in vitro-in vivo difference, changed from sixfold difference to only twofold difference with the application of the ECC. CONCLUSIONS: The study showed that taking into consideration hepatic uptake of a drug allows us to obtain satisfactory scaling factors, hence enabling the prediction of in vivo hepatic glucuronidation from in vitro data.

Honeycomb-Inspired Surface-Enhanced Raman Scattering Microarray for Large-Area Automated Testing of Urease in Saliva Samples.

Surface-enhanced Raman scattering (SERS) technology, as an important analytical tool, has been widely applied in the field of chemical and biomedical sensing. Automated testing is often combined with biochemical analysis technologies to shorten the detection time and minimize human error. The present SERS substrates for sample detection are time-consuming and subject to high human error, which are not conducive to the combination of SERS and automated testing. Here, a novel honeycomb-inspired SERS microarray is designed for large-area automated testing of urease in saliva samples to shorten the detection time and minimize human error. The honeycomb-inspired SERS microarray is decorated with hexagonal microwells and a homogeneous distribution of silver nanostars. Compared with the other four common SERS substrates, the optimal honeycomb-inspired SERS microarray exhibits the best SERS performance. The RSD of 100 SERS spectra continuously collected from saliva samples is 6.56%, and the time of one detection is reduced from 5 min to 10 s. There is a noteworthy linear relationship with a R2 of 0.982 between SERS intensity and urease concentration, indicating the quantitative detection capability of the urease activity in saliva samples. The honeycomb-inspired SERS microarray, combined with automated testing, provides a new way in which SERS technology can be widely used in biomedical applications.

Emergence of fractal geometries in the evolution of a metabolic enzyme.

Fractals are patterns that are self-similar across multiple length-scales1. Macroscopic fractals are common in nature2-4; however, so far, molecular assembly into fractals is restricted to synthetic systems5-12. Here we report the discovery of a natural protein, citrate synthase from the cyanobacterium Synechococcus elongatus, which self-assembles into Sierpinski triangles. Using cryo-electron microscopy, we reveal how the fractal assembles from a hexameric building block. Although different stimuli modulate the formation of fractal complexes and these complexes can regulate the enzymatic activity of citrate synthase in vitro, the fractal may not serve a physiological function in vivo. We use ancestral sequence reconstruction to retrace how the citrate synthase fractal evolved from non-fractal precursors, and the results suggest it may have emerged as a harmless evolutionary accident. Our findings expand the space of possible protein complexes and demonstrate that intricate and regulatable assemblies can evolve in a single substitution.

Development of an attenuated potato virus Y mutant carrying multiple mutations in helper-component protease for cross-protection.

Tobacco (Nicotiana tabacum) is one of the major cash crops in China. Potato virus Y (PVY), a representative member of the genus Potyvirus, greatly reduces the quality and yield of tobacco leaves by inducing veinal necrosis. Mild strain-mediated cross-protection is an attractive method of controlling diseases caused by PVY. Currently, there is a lack of effective and stable attenuated PVY mutants. Potyviral helper component-protease (HC-Pro) is a likely target for the development of mild strains. Our previous studies showed that the residues lysine at positions 124 and 182 (K124 and K182) in HC-Pro were involved in PVY virulence, and the conserved KITC motif in HC-Pro was involved in aphid transmission. In this study, to improve the stability of PVY mild strains, K at position 50 (K50) in KITC motif, K124, and K182 were separately substituted with glutamic acid (E), leucine (L), and arginine (R), resulting in a triple-mutant PVY-HCELR. The mutant PVY-HCELR had attenuated virulence and did not induce leaf veinal necrosis symptoms in tobacco plants and could not be transmitted by Myzus persicae. Furthermore, PVY-HCELR mutant was genetically stable after six serial passages, and only caused mild mosaic symptoms in tobacco plants even at 90 days post inoculation. The tobacco plants cross-protected by PVY-HCELR mutant showed high resistance to the wild-type PVY. This study showed that PVY-HCELR mutant was a promising mild mutant for cross-protection to control PVY.

Neuroprotective Effect of Sterculia setigera Leaves Hydroethanolic Extract.

Plants are a valuable source of information for pharmacological research and new drug discovery. The present study aimed to evaluate the neuroprotective potential of the leaves of the medicinal plant Sterculia setigera. In vitro, the effect of Sterculia setigera leaves dry hydroethanolic extract (SSE) was tested on cultured cerebellar granule neurons (CGN) survival when exposed to hydrogen peroxide (H2O2) or 6-hydroxydopamine (6-OHDA), using the viability probe fluorescein diacetate (FDA), a lactate dehydrogenase (LDH) activity assay, an immunocytochemical staining against Gap 43, and the quantification of the expression of genes involved in apoptosis, necrosis, or oxidative stress. In vivo, the effect of intraperitoneal (ip) injection of SSE was assessed on the developing brain of 8-day-old Wistar rats exposed to ethanol neurotoxicity by measuring caspase-3 activity on cerebellum homogenates, the expression of some genes in tissue extracts, the thickness of cerebellar cortical layers and motor coordination. In vitro, SSE protected CGN against H2O2 and 6-OHDA-induced cell death at a dose of 10 µg/mL, inhibited the expression of genes Casp3 and Bad, and upregulated the expression of Cat and Gpx7. In vivo, SSE significantly blocked the deleterious effect of ethanol by reducing the activity of caspase-3, inhibiting the expression of Bax and Tp53, preventing the reduction of the thickness of the internal granule cell layer of the cerebellar cortex, and restoring motor functions. Sterculia setigera exerts neuroactive functions as claimed by traditional medicine and should be a good candidate for the development of a neuroprotective treatment against neurodegenerative diseases.

Functional analysis of a wheat class III peroxidase gene, TaPer12-3A, in seed dormancy and germination.

BACKGROUND: Class III peroxidases (PODs) perform crucial functions in various developmental processes and responses to biotic and abiotic stresses. However, their roles in wheat seed dormancy (SD) and germination remain elusive. RESULTS: Here, we identified a wheat class III POD gene, named TaPer12-3A, based on transcriptome data and expression analysis. TaPer12-3A showed decreasing and increasing expression trends with SD acquisition and release, respectively. It was highly expressed in wheat seeds and localized in the endoplasmic reticulum and cytoplasm. Germination tests were performed using the transgenic Arabidopsis and rice lines as well as wheat mutant mutagenized with ethyl methane sulfonate (EMS) in Jing 411 (J411) background. These results indicated that TaPer12-3A negatively regulated SD and positively mediated germination. Further studies showed that TaPer12-3A maintained H2O2 homeostasis by scavenging excess H2O2 and participated in the biosynthesis and catabolism pathways of gibberellic acid and abscisic acid to regulate SD and germination. CONCLUSION: These findings not only provide new insights for future functional analysis of TaPer12-3A in regulating wheat SD and germination but also provide a target gene for breeding wheat varieties with high pre-harvest sprouting resistance by gene editing technology.

Phenotypic and molecular characterization of ß-lactamase-producing Klebsiella species among children discharged from hospital in Western Kenya.

BACKGROUND: The emergence and spread of ß-lactamase-producing Klebsiella spp. has been associated with a substantial healthcare burden resulting in therapeutic failures. We sought to describe the proportion of phenotypic resistance to commonly used antibiotics, characterize ß-lactamase genes among isolates with antimicrobial resistance (AMR), and assess the correlates of phenotypic AMR in Klebsiella spp. isolated from stool or rectal swab samples collected from children being discharged from hospital. METHODS: We conducted a cross-sectional study involving 245 children aged 1-59 months who were being discharged from hospitals in western Kenya between June 2016 and November 2019. Whole stool or rectal swab samples were collected and Klebsiella spp. isolated by standard microbiological culture. ß-lactamase genes were detected by PCR whilst phenotypic antimicrobial susceptibility was determined using the disc diffusion technique following standard microbiology protocols. Descriptive analyses were used to characterize phenotypic AMR and carriage of ß-lactamase-producing genes. The modified Poisson regression models were used to assess correlates of phenotypic beta-lactam resistance. RESULTS: The prevalence of ß-lactamase carriage among Klebsiella spp. isolates at hospital discharge was 62.9% (154/245). Antibiotic use during hospitalization (adjusted prevalence ratio [aPR] = 4.51; 95%CI: 1.79-11.4, p < 0.001), longer duration of hospitalization (aPR = 1.42; 95%CI: 1.14-1.77, p < 0.002), and access to treated water (aPR = 1.38; 95%CI: 1.12-1.71, p < 0.003), were significant predictors of phenotypically determined ß-lactamase. All the 154 ß-lactamase-producing Klebsiella spp. isolates had at least one genetic marker of ß-lactam/third-generation cephalosporin resistance. The most prevalent genes were blaCTX-M 142/154 (92.2%,) and blaSHV 142/154 (92.2%,) followed by blaTEM 88/154 (57.1%,) and blaOXA 48/154 (31.2%,) respectively. CONCLUSION: Carriage of ß-lactamase producing Klebsiella spp. in stool is common among children discharged from hospital in western Kenya and is associated with longer duration of hospitalization, antibiotic use, and access to treated water. The findings emphasize the need for continued monitoring of antimicrobial susceptibility patterns to inform the development and implementation of appropriate treatment guidelines. In addition, we recommend measures beyond antimicrobial stewardship and infection control within hospitals, improved sanitation, and access to safe drinking water to mitigate the spread of ß-lactamase-producing Klebsiella pathogens in these and similar settings.

PI3Kγδ inhibition suppresses key disease features in a rat model of asthma.

BACKGROUND: Two isoforms of Phosphoinositide 3-kinase (PI3K), p110γ and p110δ, are predominantly expressed in leukocytes and represent attractive therapeutic targets for the treatment of allergic asthma. The study aim was to assess the impact of administration of an inhaled PI3Kγδ inhibitor (AZD8154) in a rat model of asthma. METHODS: Firstly, we checked that the tool compound, AZD8154, inhibited rat PI3K γ & δ kinases using rat cell-based assays. Subsequently, a time-course study was conducted in a rat model of asthma to assess PI3K activity in the lung and how it is temporally associated with other key transcription pathways and asthma like features of the model. Finally, the impact on lung dosed AZD8154 on target engagement, pathway specificity, airway inflammation and lung function changes was assessed. RESULTS: Data showed that AZD8154 could inhibit rat PI3K γ & δ isoforms and, in a rat model of allergic asthma the PI3K pathway was activated in the lung. Intratracheal administration of AZD8154 caused a dose related suppression PI3K pathway activation (reduction in pAkt) and unlike after budesonide treatment, STAT and NF-κB pathways were not affected by AZD8154. The suppression of the PI3K pathway led to a marked inhibition of airway inflammation and reduction in changes in lung function. CONCLUSION: These data show that a dual PI3Kγδ inhibitor suppress key features of disease in a rat model of asthma to a similar degree as budesonide and indicate that dual PI3Kγδ inhibition may be an effective treatment for people suffering from allergic asthma.

CoCas9 is a compact nuclease from the human microbiome for efficient and precise genome editing.

The expansion of the CRISPR-Cas toolbox is highly needed to accelerate the development of therapies for genetic diseases. Here, through the interrogation of a massively expanded repository of metagenome-assembled genomes, mostly from human microbiomes, we uncover a large variety (n = 17,173) of type II CRISPR-Cas loci. Among these we identify CoCas9, a strongly active and high-fidelity nuclease with reduced molecular size (1004 amino acids) isolated from an uncultivated Collinsella species. CoCas9 is efficiently co-delivered with its sgRNA through adeno associated viral (AAV) vectors, obtaining efficient in vivo editing in the mouse retina. With this study we uncover a collection of previously uncharacterized Cas9 nucleases, including CoCas9, which enriches the genome editing toolbox.

High prevalence of multidrug-resistant Enterobacterales carrying extended-spectrum beta-lactamase and AmpC genes isolated from neonatal sepsis in Ahvaz, Iran.

OBJECTIVES: In the recent years, multidrug resistant (MDR) neonatal septicemia-causing Enterobacterales has been dramatically increased due to the extended-spectrum beta-lactamases (ESBLs) and AmpC enzymes. This study aimed to assess the antibiotic resistance pattern, prevalence of ESBLs/AmpC beta-lactamase genes, and Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) fingerprints in Enterobacterales isolated from neonatal sepsis. RESULTS: In total, 59 Enterobacterales isolates including 41 (69.5%) Enterobacter species, 15 (25.4%) Klebsiella pneumoniae and 3 (5.1%) Escherichia coli were isolated respectively. Resistance to ceftazidime and cefotaxime was seen in all of isolates. Furthermore, all of them were multidrug-resistant (resistant to three different antibiotic categories). The phenotypic tests showed that 100% of isolates were ESBL-positive. Moreover, AmpC production was observed in 84.7% (n = 50/59) of isolates. Among 59 ESBL-positive isolates, the highest percentage belonged to blaCTX-M-15 gene (66.1%) followed by blaCTX-M (45.8%), blaCTX-M-14 (30.5%), blaSHV (28.8%), and blaTEM (13.6%). The frequency of blaDHA, blaEBC, blaMOX and blaCIT genes were 24%, 24%, 4%, and 2% respectively. ERIC-PCR analysis revealed that Enterobacterales isolates were genetically diverse. The remarkable prevalence of MDR Enterobacterales isolates carrying ESBL and AmpC beta-lactamase genes emphasizes that efficient surveillance measures are essential to avoid the more expansion of drug resistance amongst isolates.

Genome-wide characterization of DNA methyltransferase family genes implies GhDMT6 improving tolerance of salt and drought on cotton.

BACKGROUND: DNA methylation is an important epigenetic mode of genomic DNA modification and plays a vital role in maintaining epigenetic content and regulating gene expression. Cytosine-5 DNA methyltransferase (C5-MTase) are the key enzymes in the process of DNA methylation. However, there is no systematic analysis of the C5-MTase in cotton so far, and the function of DNMT2 genes has not been studied. METHODS: In this study, the whole genome of cotton C5-MTase coding genes was identified and analyzed using a bioinformatics method based on information from the cotton genome, and the function of GhDMT6 was further validated by VIGS experiments and subcellular localization analysis. RESULTS: 33 C5-MTases were identified from three cotton genomes, and were divided into four subfamilies by systematic evolutionary analysis. After the protein domain alignment of C5-MTases in cotton, 6 highly conserved motifs were found in the C-terminus of 33 proteins involved in methylation modification, which indicated that C5-MTases had a basic catalytic methylation function. These proteins were divided into four classes based on the N-terminal difference, of which DNMT2 lacks the N-terminal regulatory domain. The expression of C5-MTases in different parts of cotton was different under different stress treatments, which indicated the functional diversity of cotton C5-MTase gene family. Among the C5-MTases, the GhDMT6 had a obvious up-regulated expression. After silencing GhDMT6 with VIGS, the phenotype of cotton seedlings under different stress treatments showed a significant difference. Compared with cotton seedlings that did not silence GhDMT6, cotton seedlings silencing GhDMT6 showed significant stress resistance. CONCLUSION: The results show that C5-MTases plays an important role in cotton stress response, which is beneficial to further explore the function of DNMT2 subfamily genes.

The α-tubulin acetyltransferase ATAT1: structure, cellular functions, and its emerging role in human diseases.

The acetylation of α-tubulin on lysine 40 is a well-studied post-translational modification which has been associated with the presence of long-lived stable microtubules that are more resistant to mechanical breakdown. The discovery of α-tubulin acetyltransferase 1 (ATAT1), the enzyme responsible for lysine 40 acetylation on α-tubulin in a wide range of species, including protists, nematodes, and mammals, dates to about a decade ago. However, the role of ATAT1 in different cellular activities and molecular pathways has been only recently disclosed. This review comprehensively summarizes the most recent knowledge on ATAT1 structure and substrate binding and analyses the involvement of ATAT1 in a variety of cellular processes such as cell motility, mitosis, cytoskeletal organization, and intracellular trafficking. Finally, the review highlights ATAT1 emerging roles in human diseases and discusses ATAT1 potential enzymatic and non-enzymatic roles and the current efforts in developing ATAT1 inhibitors.

Detection of OXA-181 Carbapenemase in Shigella flexneri.

We report the detection of OXA-181 carbapenemase in an azithromycin-resistant Shigella spp. bacteria in an immunocompromised patient. The emergence of OXA-181 in Shigella spp. bacteria raises concerns about the global dissemination of carbapenem resistance in Enterobacterales and its implications for the treatment of infections caused by Shigella bacteria.