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International Journal of Molecular... Apr 2024Demyelinating Charcot-Marie-Tooth 4G (CMT4G) results from a recessive mutation in the 5'UTR region of the Hexokinase 1 (HK1) gene. HK participates in mitochondrial...
The 5'-UTR Mutation in Charcot-Marie-Tooth 4G Disease Alters Hexokinase 1 Binding to Voltage-Dependent Anion Channel-1 and Leads to Dysfunctional Mitochondrial Calcium Buffering.
Demyelinating Charcot-Marie-Tooth 4G (CMT4G) results from a recessive mutation in the 5'UTR region of the Hexokinase 1 (HK1) gene. HK participates in mitochondrial calcium homeostasis by binding to the Voltage-Dependent Anion Channel (VDAC), through its N-terminal porin-binding domain. Our hypothesis is that CMT4G mutation results in a broken interaction between mutant HK1 and VDAC, disturbing mitochondrial calcium homeostasis. We studied a cohort of 25 CMT4G patients recruited in the French gypsy population. The disease was characterized by a childhood onset, an intermediate demyelinating pattern, and a significant phenotype leading to becoming wheelchair-bound by the fifth decade of life. Co-IP and PLA studies indicated a strong decreased interaction between VDAC and HK1 in the patients' PBMCs and sural nerve. We observed that either wild-type HK1 expression or a peptide comprising the 15 aa of the N-terminal wild-type HK1 administration decreased mitochondrial calcium release in HEK293 cells. However, mutated CMT4G HK1 or the 15 aa of the mutated HK1 was unable to block mitochondrial calcium release. Taken together, these data show that the CMT4G-induced modification of the HK1 N-terminus disrupts HK1-VDAC interaction. This alters mitochondrial calcium buffering that has been shown to be critical for myelin sheath maintenance.
Topics: Adolescent; Adult; Child; Female; Humans; Male; Middle Aged; Young Adult; 5' Untranslated Regions; Calcium; Charcot-Marie-Tooth Disease; HEK293 Cells; Hexokinase; Mitochondria; Mutation; Protein Binding; Voltage-Dependent Anion Channel 1
PubMed: 38673950
DOI: 10.3390/ijms25084364 -
International Journal of Molecular... Apr 2024Arbuscular mycorrhizal fungi symbiosis plays important roles in enhancing plant tolerance to biotic and abiotic stresses. Aquaporins have also been linked to improved...
Arbuscular mycorrhizal fungi symbiosis plays important roles in enhancing plant tolerance to biotic and abiotic stresses. Aquaporins have also been linked to improved drought tolerance in plants and the regulation of water transport. However, the mechanisms that underlie this association remain to be further explored. In this study, we found that arbuscular mycorrhiza fungi symbiosis could induce the gene expression of the aquaporin ZmTIP2;3 in maize roots. Moreover, compared with the wild-type plants, the maize mutant also showed a lower total biomass, colonization rate, relative water content, and POD and SOD activities after arbuscular mycorrhiza fungi symbiosis under drought stress. qRT-PCR assays revealed reduced expression levels of stress genes including , , and in the maize mutant. Taken together, these data suggest that plays an important role in promoting maize tolerance to drought stress during arbuscular mycorrhiza fungi symbiosis.
Topics: Zea mays; Mycorrhizae; Symbiosis; Droughts; Aquaporins; Gene Expression Regulation, Plant; Plant Proteins; Stress, Physiological; Plant Roots; Drought Resistance
PubMed: 38673792
DOI: 10.3390/ijms25084205 -
Cells Apr 2024A deficiency in the shortest dystrophin-gene product, Dp71, is a pivotal aggravating factor for intellectual disabilities in Duchenne muscular dystrophy (DMD). Recent...
A deficiency in the shortest dystrophin-gene product, Dp71, is a pivotal aggravating factor for intellectual disabilities in Duchenne muscular dystrophy (DMD). Recent advances in preclinical research have achieved some success in compensating both muscle and brain dysfunctions associated with DMD, notably using exon skipping strategies. However, this has not been studied for distal mutations in the gene leading to Dp71 loss. In this study, we aimed to restore brain Dp71 expression in the Dp71-null transgenic mouse using an adeno-associated virus (AAV) administrated either by intracardiac injections at P4 (ICP4) or by bilateral intracerebroventricular (ICV) injections in adults. ICP4 delivery of the AAV9-Dp71 vector enabled the expression of 2 to 14% of brain Dp71, while ICV delivery enabled the overexpression of Dp71 in the hippocampus and cortex of adult mice, with anecdotal expression in the cerebellum. The restoration of Dp71 was mostly located in the glial endfeet that surround capillaries, and it was associated with partial localization of Dp71-associated proteins, α1-syntrophin and AQP4 water channels, suggesting proper restoration of a scaffold of proteins involved in blood-brain barrier function and water homeostasis. However, this did not result in significant improvements in behavioral disturbances displayed by Dp71-null mice. The potential and limitations of this AAV-mediated strategy are discussed. This proof-of-concept study identifies key molecular markers to estimate the efficiencies of Dp71 rescue strategies and opens new avenues for enhancing gene therapy targeting cognitive disorders associated with a subgroup of severely affected DMD patients.
Topics: Animals; Male; Mice; Aquaporin 4; Behavior, Animal; Brain; Calcium-Binding Proteins; Dependovirus; Disease Models, Animal; Dystrophin; Genetic Therapy; Genetic Vectors; Membrane Proteins; Mice, Inbred C57BL; Mice, Knockout; Muscle Proteins; Muscular Dystrophy, Duchenne
PubMed: 38667332
DOI: 10.3390/cells13080718 -
BMC Genomics Apr 2024Klebsiella pneumoniae, a notorious pathogen for causing nosocomial infections has become a major cause of neonatal septicemia, leading to high morbidity and mortality...
BACKGROUND
Klebsiella pneumoniae, a notorious pathogen for causing nosocomial infections has become a major cause of neonatal septicemia, leading to high morbidity and mortality worldwide. This opportunistic bacterium has become highly resistant to antibiotics due to the widespread acquisition of genes encoding a variety of enzymes such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases. We collected Klebsiella pneumoniae isolates from a local tertiary care hospital from February 2019-February 2021. To gain molecular insight into the resistome, virulome, and genetic environment of significant genes of multidrug-resistant K. pneumoniae isolates, we performed the short-read whole-genome sequencing of 10 K. pneumoniae isolates recovered from adult patients, neonates, and hospital tap water samples.
RESULTS
The draft genomes of the isolates varied in size, ranging from 5.48 to 5.96 Mbp suggesting the genome plasticity of this pathogen. Various genes conferring resistance to different classes of antibiotics e.g., aminoglycosides, quinolones, sulfonamides, tetracycline, and trimethoprim were identified in all sequenced isolates. The highest resistance was observed towards carbapenems, which has been putatively linked to the presence of both class B and class D carbapenemases, bla and bla, respectively. Moreover, the biocide resistance gene qacEdelta1 was found in 6/10 of the sequenced strains. The sequenced isolates exhibited a broad range of sequence types and capsular types. The significant antibiotic resistance genes (ARGs) were bracketed by a variety of mobile genetic elements (MGEs). Various spontaneous mutations in genes other than the acquired antibiotic-resistance genes were observed, which play an indirect role in making these bugs resistant to antibiotics. Loss or deficiency of outer membrane porins, combined with ESBL production, played a significant role in carbapenem resistance in our sequenced isolates. Phylogenetic analysis revealed that the study isolates exhibited evolutionary relationships with strains from China, India, and the USA suggesting a shared evolutionary history and potential dissemination of similar genes amongst the isolates of different origins.
CONCLUSIONS
This study provides valuable insight into the presence of multiple mechanisms of carbapenem resistance in K. pneumoniae strains including the acquisition of multiple antibiotic-resistance genes through mobile genetic elements. Identification of rich mobilome yielded insightful information regarding the crucial role of insertion sequences, transposons, and integrons in shaping the genome of bacteria for the transmission of various resistance-associated genes. Multi-drug resistant isolates that had the fewest resistance genes exhibited a significant number of mutations. K. pneumoniae isolate from water source displayed comparable antibiotic resistance determinants to clinical isolates and the highest number of virulence-associated genes suggesting the possible interplay of ARGs amongst bacteria from different sources.
Topics: Klebsiella pneumoniae; Drug Resistance, Multiple, Bacterial; Carbapenems; Humans; Whole Genome Sequencing; Genome, Bacterial; beta-Lactamases; Anti-Bacterial Agents; Phylogeny; Klebsiella Infections; Microbial Sensitivity Tests; Bacterial Proteins
PubMed: 38664636
DOI: 10.1186/s12864-024-10139-y -
Theriogenology Jul 2024The freeze-thawing process induces osmotic changes that may affect the membrane domain location of aquaporins' (AQP) in spermatozoa. Recent studies suggest that changes...
The freeze-thawing process induces osmotic changes that may affect the membrane domain location of aquaporins' (AQP) in spermatozoa. Recent studies suggest that changes in AQP3 localization allows better sperm osmo-adaptation, improving the cryoresistance. Ultra-rapid freezing is an alternative cryopreservation technique that requires less equipment than conventional freezing, and it is faster, simpler and can be used in the field. This study aimed to determine the influence of freezing-thawing rates (slow (control) vs. ultra-rapid) on AQP3 expression and location in the spermatozoa from small ruminants (sheep and goats) and its relationship with sperm cryo-damage. Spermatozoa were collected from 10 Merino rams and 10 Murciano-Granadina bucks. The presence and distribution of AQP3 were assessed by Western blotting and immunocytochemistry (ICC), employing a commercial rabbit polyclonal antibody. Sperm motility was CASA system-analyzed, and membrane and acrosome integrity assessed by fluorescence (PI/PNA-FITC). Western blotting did not detect a significant effect of freezing-thawing rate on the amount of AQP3 while ICC found freezing-thawing rate affecting AQP3 location (P < 0.05). In both species, the percentages of spermatozoa showing AQP3 in the post-acrosome region, mid-piece, and principal piece of the tail were greater in samples cryopreserved by slow freezing-thawing (control) than ultra-rapid freezing-thawing rates (P < 0.05). Spermatozoa cryopreserved using ultra-rapid freezing-thawing showed decrease motility, plasma membrane, and acrosome integrity (P < 0.05), which might be related, at least in part, to a lower expression of AQP3. In conclusion, the cooling rate modifies the location of AQP3 in spermatozoa of sheep and goat, which might be associated with sperm cryosurvival.
Topics: Animals; Male; Goats; Aquaporin 3; Spermatozoa; Cryopreservation; Sheep; Semen Preservation; Freezing; Sperm Motility
PubMed: 38663138
DOI: 10.1016/j.theriogenology.2024.04.008 -
Zhongguo Dang Dai Er Ke Za Zhi =... Apr 2024To study the distribution, drug resistance, and biofilm characteristics of carbapenem-resistant (CRAB) isolated from hospitalized children, providing a reference for...
OBJECTIVES
To study the distribution, drug resistance, and biofilm characteristics of carbapenem-resistant (CRAB) isolated from hospitalized children, providing a reference for the prevention and treatment of CRAB infections in hospitalized children.
METHODS
Forty-eight CRAB strains isolated from January 2019 to December 2022 were classified into epidemic and sporadic strains using repetitive extragenic palindromic sequence-based polymerase chain reaction. The drug resistance, biofilm phenotypes, and gene carriage of these two types of strains were compared.
RESULTS
Both the 22 epidemic strains and the 26 sporadic strains were producers of Class D carbapenemases or extended-spectrum β-lactamases with downregulated outer membrane porins, harboring the , , and genes. The biofilm formation capability of the sporadic strains was stronger than that of the epidemic strains (<0.05). Genes related to biofilm formation, including , , , , and , were detected in both epidemic and sporadic strains, with a higher detection rate of the gene in epidemic strains (<0.05).
CONCLUSIONS
CRAB strains are colonized in the hospital, with sporadic strains having a stronger ability to form biofilms, suggesting the potential for forming new clonal transmissions in the hospital. Continuous monitoring of the epidemic trends of CRAB and early warning of the distribution of epidemic strains are necessary to reduce the risk of CRAB infections in hospitalized children.
Topics: Acinetobacter baumannii; Biofilms; Carbapenems; Humans; Child; Acinetobacter Infections; Child, Preschool; beta-Lactamases; Child, Hospitalized; Drug Resistance, Bacterial; Anti-Bacterial Agents; Female; Infant; Male; Microbial Sensitivity Tests; Bacterial Proteins
PubMed: 38660899
DOI: 10.7499/j.issn.1008-8830.2309058 -
Frontiers in Cellular and Infection... 2024The global emergence of antimicrobial resistance to multiple antibiotics has recently become a significant concern. Gram-negative bacteria, known for their ability to... (Review)
Review
The global emergence of antimicrobial resistance to multiple antibiotics has recently become a significant concern. Gram-negative bacteria, known for their ability to acquire mobile genetic elements such as plasmids, represent one of the most hazardous microorganisms. This phenomenon poses a serious threat to public health. Notably, the significance of tigecycline, a member of the antibiotic group glycylcyclines and derivative of tetracyclines has increased. Tigecycline is one of the last-resort antimicrobial drugs used to treat complicated infections caused by multidrug-resistant (MDR) bacteria, extensively drug-resistant (XDR) bacteria or even pan-drug-resistant (PDR) bacteria. The primary mechanisms of tigecycline resistance include efflux pumps' overexpression, genes and outer membrane porins. Efflux pumps are crucial in conferring multi-drug resistance by expelling antibiotics (such as tigecycline by direct expelling) and decreasing their concentration to sub-toxic levels. This review discusses the problem of tigecycline resistance, and provides important information for understanding the existing molecular mechanisms of tigecycline resistance in . The emergence and spread of pathogens resistant to last-resort therapeutic options stands as a major global healthcare concern, especially when microorganisms are already resistant to carbapenems and/or colistin.
Topics: Tigecycline; Anti-Bacterial Agents; Enterobacteriaceae; Humans; Drug Resistance, Multiple, Bacterial; Drug Resistance, Bacterial; Minocycline; Microbial Sensitivity Tests; Plasmids; Enterobacteriaceae Infections
PubMed: 38655285
DOI: 10.3389/fcimb.2024.1289396 -
Environmental Science and Pollution... May 2024Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore...
Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore are formed extracellularly and diffuse through porins across membranes into bacterial cells. Siderophores can bind heavy metals facilitating their influx into cells via the same mechanism. The aim of the studies was to determine the ability of siderophore-producing bacteria isolated from soils in the north-west part of Wedel Jarlsberg Land (Spitsbergen) to chelate non-Fe metals (Al, Cd, Co, Cu, Hg, Mn, Sn, and Zn). Specially modified blue agar plates were used, where Fe was substituted by Al, Cd, Co, Cu, Hg, Mn, Sn, or Zn in metal-chrome azurol S (CAS) complex, which retained the blue color. It has been proven that 31 out of 33 strains were capable of producing siderophores that bind to Fe, as well as other metals. Siderophores from Pantoea sp. 24 bound only Fe and Zn, and O. anthropi 55 did not produce any siderophores in pure culture. The average efficiency of Cd, Co, Cu, Mn, Sn, and Zn chelation was either comparable or higher than that of Fe, while Al and Hg showed significantly lower efficiency. Siderophores produced by S. maltophilia 54, P. luteola 27, P. luteola 46, and P. putida 49 exhibited the highest non-Fe metal chelation activity. It can be concluded that the siderophores of these bacteria may constitute an integral part of the metal bioleaching preparation, and this fact will be the subject of further research.
Topics: Siderophores; Soil Pollutants; Biodegradation, Environmental; Soil Microbiology; Metals, Heavy; Soil; Bacteria
PubMed: 38652189
DOI: 10.1007/s11356-024-33356-0 -
Multiple Sclerosis (Houndmills,... May 2024Optic neuritis (ON) is a common feature of inflammatory demyelinating diseases (IDDs) such as multiple sclerosis (MS), aquaporin 4-antibody neuromyelitis optica spectrum...
Optic chiasm involvement in multiple sclerosis, aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein-associated disease.
BACKGROUND
Optic neuritis (ON) is a common feature of inflammatory demyelinating diseases (IDDs) such as multiple sclerosis (MS), aquaporin 4-antibody neuromyelitis optica spectrum disorder (AQP4 + NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, the involvement of the optic chiasm (OC) in IDD has not been fully investigated.
AIMS
To examine OC differences in non-acute IDD patients with (ON+) and without ON (ON-) using magnetisation transfer ratio (MTR), to compare differences between MS, AQP4 + NMOSD and MOGAD and understand their associations with other neuro-ophthalmological markers.
METHODS
Twenty-eight relapsing-remitting multiple sclerosis (RRMS), 24 AQP4 + NMOSD, 28 MOGAD patients and 32 healthy controls (HCs) underwent clinical evaluation, MRI and optical coherence tomography (OCT) scan. Multivariable linear regression models were applied.
RESULTS
ON + IDD patients showed lower OC MTR than HCs (28.87 ± 4.58 vs 31.65 ± 4.93; = 0.004). When compared with HCs, lower OC MTR was found in ON + AQP4 + NMOSD (28.55 ± 4.18 vs 31.65 ± 4.93; = 0.020) and MOGAD (28.73 ± 4.99 vs 31.65 ± 4.93; = 0.007) and in ON- AQP4 + NMOSD (28.37 ± 7.27 vs 31.65 ± 4.93; = 0.035). ON+ RRMS had lower MTR than ON- RRMS (28.87 ± 4.58 vs 30.99 ± 4.76; = 0.038). Lower OC MTR was associated with higher number of ON (regression coefficient (RC) = -1.15, 95% confidence interval (CI) = -1.819 to -0.490, = 0.001), worse visual acuity (RC = -0.026, 95% CI = -0.041 to -0.011, = 0.001) and lower peripapillary retinal nerve fibre layer (pRNFL) thickness (RC = 1.129, 95% CI = 0.199 to 2.059, = 0.018) when considering the whole IDD group.
CONCLUSION
OC microstructural damage indicates prior ON in IDD and is linked to reduced vision and thinner pRNFL.
Topics: Adult; Female; Humans; Male; Middle Aged; Aquaporin 4; Autoantibodies; Magnetic Resonance Imaging; Multiple Sclerosis, Relapsing-Remitting; Myelin-Oligodendrocyte Glycoprotein; Neuromyelitis Optica; Optic Chiasm; Optic Neuritis; Tomography, Optical Coherence; Young Adult
PubMed: 38646958
DOI: 10.1177/13524585241240420 -
Sichuan Da Xue Xue Bao. Yi Xue Ban =... Mar 2024To investigate the clinical characteristics and molecular epidemiology of carbapenem-resistant (CRKP) isolated from patients with bloodstream infections in a large...
OBJECTIVE
To investigate the clinical characteristics and molecular epidemiology of carbapenem-resistant (CRKP) isolated from patients with bloodstream infections in a large tertiary-care general hospital in Southwest China.
METHODS
A total of 131 strains of non-repeating CRKP were collected from the blood cultures of patients who had bloodstream infections in 2015-2019. The strains were identified by VITEK-2, a fully automated microbial analyzer, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The minimum inhibitory concentration (MIC) was determined by microbroth dilution method. The common carbapenemase resistant genes and virulence factors were identified by PCR. Homology analysis was performed by multilocus sequencing typing. Whole genome sequencing was performed to analyze the genomic characteristics of CRKP without carbapenemase.
RESULTS
The 131 strains of CRKP showed resistance to common antibiotics, except for polymyxin B (1.6% resistance rate) and tigacycline (8.0% resistance rate). A total of 105 (80.2%) CRKP strains carried the carbapenemase () resistance gene, 15 (11.4%) strains carried the New Delhi Metallo-β-lactamase () gene, and 4 (3.1%) isolates carried both and genes. Sequence typing (ST) 11 (74.0%) was the dominant sequence type. High detection rates for (96.2%), (98.5%), (100%), and other virulence genes were reported. One hypervirulent CRKP strain was detected. The seven strains of CRKP that did not produce carbapenemase were shown to carry or genes and had anomalies in membrane porins OMPK35 and OMPK36, according to whole genome sequencing.
CONCLUSION
In a large-scale tertiary-care general hospital, CRKP mainly carries the gene, has a high drug resistance rate to a variety of antibiotics, and possesses multiple virulence genes. Attention should be paid to CRKP strains with high virulence.
Topics: Humans; Klebsiella pneumoniae; Bacterial Proteins; beta-Lactamases; Klebsiella Infections; China; Carbapenems; Microbial Sensitivity Tests; Virulence Factors; Molecular Epidemiology; Anti-Bacterial Agents; Virulence; Male; Female; Carbapenem-Resistant Enterobacteriaceae; Middle Aged; Bacteremia; Whole Genome Sequencing
PubMed: 38645859
DOI: 10.12182/20240360202