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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 -
BioRxiv : the Preprint Server For... Apr 2024is associated with multidrug resistant (MDR) infections in healthcare settings, with fluoroquinolones such as ciprofloxacin being currently ineffective. Clinical...
is associated with multidrug resistant (MDR) infections in healthcare settings, with fluoroquinolones such as ciprofloxacin being currently ineffective. Clinical isolates largely harbor mutations in the GyrA and TopoIV fluoroquinolone targets, as well as mutations that increase expression of drug resistance-nodulation-division (RND) efflux pumps. Factors critical for maintaining fitness levels of pump overproducers are uncharacterized despite their prevalence in clinical isolates. We here identify proteins that contribute to the fitness of FQR strains overexpressing three known RND systems using high-density insertion mutagenesis. Overproduction of the AdeFGH efflux pump caused hypersensitization to defects in outer membrane homeostatic regulation, including lesions that reduced LOS biosynthesis and blocked production of the major porin. In contrast, AdeAB pump overproduction, which does not affect the outer membrane pump component, was relatively tolerant to loss of these functions, consistent with outer membrane protein overproduction being the primary disruptive component. Surprisingly, overproduction of proton-transporting efflux pumps had little impact on cytosolic pH, consistent with a compensatory response to pump activity. The most striking transcriptional changes were associated with AdeFGH pump overproduction, resulting in activation of the phenylacetate (PAA) degradation regulon. Disruption of the PAA pathway resulted in cytosolic acidification and defective expression of genes involved in protection from peroxide stress. These results indicate that the RND outer membrane protein overproduction is compensated by cytoplasmic buffering and maintenance of outer membrane integrity in to facilitate fitness of FQR isolates.
PubMed: 38645180
DOI: 10.1101/2023.10.03.560562 -
BMC Plant Biology Apr 2024Aquaporins (AQPs) facilitate water diffusion across biological membranes and are involved in all phases of growth and development. Small and basic intrinsic proteins...
BACKGROUND
Aquaporins (AQPs) facilitate water diffusion across biological membranes and are involved in all phases of growth and development. Small and basic intrinsic proteins (SIPs) belong to the fourth subfamily of the plant AQPs. Although SIPs are widely present in higher plants, reports on SIPs are limited. Rice is one of the major food crops in the world, and water use is an important factor affecting rice growth and development; therefore, this study aimed to provide information relevant to the function and environmental response of the rice SIP gene family.
RESULTS
The rice (Oryza sativa L. japonica) genome encodes two SIP-like genes, OsSIP1 and OsSIP2, whose products are predominantly located in the endoplasmic reticulum (ER) membrane but transient localization to the plasma membrane is not excluded. Heterologous expression in a yeast aquaglyceroporin-mutant fps1Δ showed that both OsSIP1 and OsSIP2 made the cell more sensitive to KCl, sorbitol and HO, indicating facilitated permeation of water and hydrogen peroxide. In addition, the yeast cells expressing OsSIP2 were unable to efflux the toxic methylamine taken up by the endogenous MEP permeases, but OsSIP1 showed subtle permeability to methylamine, suggesting that OsSIP1 may have a wider conducting pore than OsSIP2. Expression profiling in different rice tissues or organs revealed that OsSIP1 was expressed in all tissues tested, whereas OsSIP2 was preferentially expressed in anthers and weakly expressed in other tissues. Consistent with this, histochemical staining of tissues expressing the promoter-β-glucuronidase fusion genes revealed their tissue-specific expression profile. In rice seedlings, both OsSIPs were upregulated to varied levels under different stress conditions, including osmotic shock, high salinity, unfavorable temperature, redox challenge and pathogen attack, as well as by hormonal treatments such as GA, ABA, MeJA, SA. However, a reduced expression of both OsSIPs was observed under dehydration treatment.
CONCLUSIONS
Our results suggest that SIP-like aquaporins are not restricted to the ER membrane and are likely to be involved in unique membrane functions in substrate transport, growth and development, and environmental response.
Topics: Oryza; Aquaporins; Plant Proteins; Gene Expression Regulation, Plant; Endoplasmic Reticulum
PubMed: 38644479
DOI: 10.1186/s12870-024-05002-x -
Frontiers in Cellular and Infection... 2024The dissemination of antibiotic resistance in poses a significant threat to public health worldwide. This review provides a comprehensive update on the diverse... (Review)
Review
The dissemination of antibiotic resistance in poses a significant threat to public health worldwide. This review provides a comprehensive update on the diverse mechanisms employed by in developing resistance to antibiotics. We primarily focus on pathotypes of (e.g., uropathogenic ) and investigate the genetic determinants and molecular pathways that confer resistance, shedding light on both well-characterized and recently discovered mechanisms. The most prevalent mechanism continues to be the acquisition of resistance genes through horizontal gene transfer, facilitated by mobile genetic elements such as plasmids and transposons. We discuss the role of extended-spectrum -lactamases (ESBLs) and carbapenemases in conferring resistance to -lactam antibiotics, which remain vital in clinical practice. The review covers the key resistant mechanisms, including: 1) Efflux pumps and porin mutations that mediate resistance to a broad spectrum of antibiotics, including fluoroquinolones and aminoglycosides; 2) adaptive strategies employed by , including biofilm formation, persister cell formation, and the activation of stress response systems, to withstand antibiotic pressure; and 3) the role of regulatory systems in coordinating resistance mechanisms, providing insights into potential targets for therapeutic interventions. Understanding the intricate network of antibiotic resistance mechanisms in is crucial for the development of effective strategies to combat this growing public health crisis. By clarifying these mechanisms, we aim to pave the way for the design of innovative therapeutic approaches and the implementation of prudent antibiotic stewardship practices to preserve the efficacy of current antibiotics and ensure a sustainable future for healthcare.
Topics: Humans; Escherichia coli; Escherichia coli Infections; Microbial Sensitivity Tests; Anti-Bacterial Agents; beta-Lactamases; Drug Resistance, Microbial
PubMed: 38638826
DOI: 10.3389/fcimb.2024.1387497 -
Journal of the American Chemical Society May 2024Protein lipidation dynamically controls protein localization and function within cellular membranes. A unique form of protein -fatty acylation in , termed protein...
Protein lipidation dynamically controls protein localization and function within cellular membranes. A unique form of protein -fatty acylation in , termed protein -mycoloylation, involves the attachment of mycolic acids─unusually large and hydrophobic fatty acids─to serine residues of proteins in these organisms' outer mycomembrane. However, as with other forms of protein lipidation, the scope and functional consequences of protein -mycoloylation are challenging to investigate due to the inherent difficulties of enriching and analyzing lipidated peptides. To facilitate the analysis of protein lipidation and enable the comprehensive profiling and site mapping of protein -mycoloylation, we developed a chemical proteomics strategy integrating metabolic labeling, click chemistry, cleavable linkers, and a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method employing LC separation and complementary fragmentation methods tailored to the analysis of lipophilic, MS-labile -acylated peptides. Using these tools in the model organism , we identified approximately 30 candidate -mycoloylated proteins, including porins, mycoloyltransferases, secreted hydrolases, and other proteins with cell envelope-related functions─consistent with a role for -mycoloylation in targeting proteins to the mycomembrane. Site mapping revealed that many of the proteins contained multiple spatially proximal modification sites, which occurred predominantly at serine residues surrounded by conformationally flexible peptide motifs. Overall, this study (i) discloses the putative protein -mycoloylome for the first time, (ii) yields new insights into the undercharacterized proteome of the mycomembrane, which is a hallmark of important pathogens (e.g., , ), and (iii) provides generally applicable chemical strategies for the proteomic analysis of protein lipidation.
Topics: Proteomics; Bacterial Proteins; Corynebacterium glutamicum; Mycolic Acids; Tandem Mass Spectrometry; Chromatography, Liquid; Acylation; Click Chemistry
PubMed: 38635392
DOI: 10.1021/jacs.4c02278 -
Journal of Agricultural and Food... May 2024The conversion of raw barley ( L.) to malt requires a process of controlled germination, where the grain is submerged in water to raise the moisture content to >40%. The...
The conversion of raw barley ( L.) to malt requires a process of controlled germination, where the grain is submerged in water to raise the moisture content to >40%. The transmembrane proteins, aquaporins, influence water uptake during the initial stage of controlled germination, yet little is known of their involvement in malting. With the current focus on sustainability, understanding the mechanisms of water uptake and usage during the initial stages of malting has become vital in improving efficient malting practices. In this study, we used quantitative proteomics analysis of two malting barley genotypes demonstrating differing water-uptake phenotypes in the initial stages of malting. Our study quantified 19 transmembrane proteins from nine families, including seven distinct aquaporin isoforms, including the plasma intrinsic proteins (PIPs) PIP1;1, PIP2;1, and PIP2;4 and the tonoplast intrinsic proteins (TIPs) TIP1;1, TIP2;3, TIP3;1, and TIP3;2. Our findings suggest that the presence of TIP1;1, TIP3;1, and TIP3;2 in the mature barley grain proteome is essential for facilitating water uptake, influencing cell turgor and the formation of large central lytic vacuoles aiding storage reserve hydrolysis and endosperm modification efficiency. This study proposes that TIP3s mediate water uptake in malting barley grain, offering potential breeding targets for improving sustainable malting practices.
Topics: Hordeum; Aquaporins; Germination; Plant Proteins; Water; Seeds; Plant Breeding; Edible Grain; Proteomics
PubMed: 38635353
DOI: 10.1021/acs.jafc.4c00884 -
The Kaohsiung Journal of Medical... Jun 2024Slow transit constipation (STC) is one of the most common gastrointestinal disorders in children and adults worldwide. Paeoniflorin (PF), a monoterpene glycoside...
Slow transit constipation (STC) is one of the most common gastrointestinal disorders in children and adults worldwide. Paeoniflorin (PF), a monoterpene glycoside compound extracted from the dried root of Paeonia lactiflora, has been found to alleviate STC, but the mechanisms of its effect remain unclear. The present study aimed to investigate the effects and mechanisms of PF on intestinal fluid metabolism and visceral sensitization in rats with compound diphenoxylate-induced STC. Based on the evaluation of the laxative effect, the abdominal withdrawal reflex test, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry were used to detect the visceral sensitivity, fluid metabolism-related proteins, and acid-sensitive ion channel 3/extracellular signal-regulated kinase (ASIC3/ERK) pathway-related molecules. PF treatment not only attenuated compound diphenoxylate-induced constipation symptoms and colonic pathological damage in rats but also ameliorated colonic fluid metabolic disorders and visceral sensitization abnormalities, as manifested by increased colonic goblet cell counts and mucin2 protein expression, decreased aquaporin3 protein expression, improved abdominal withdrawal reflex scores, reduced visceral pain threshold, upregulated serum 5-hydroxytryptamine, and downregulated vasoactive intestinal peptide levels. Furthermore, PF activated the colonic ASIC3/ERK pathway in STC rats, and ASIC3 inhibition partially counteracted PF's modulatory effects on intestinal fluid and visceral sensation. In conclusion, PF alleviated impaired intestinal fluid metabolism and abnormal visceral sensitization in STC rats and thus relieved their symptoms through activation of the ASIC3/ERK pathway.
Topics: Animals; Glucosides; Monoterpenes; Acid Sensing Ion Channels; Constipation; Rats; Male; MAP Kinase Signaling System; Rats, Sprague-Dawley; Colon; Gastrointestinal Transit; Aquaporin 3; Serotonin; Visceral Pain
PubMed: 38634140
DOI: 10.1002/kjm2.12829 -
BMC Plant Biology Apr 2024Tonoplast intrinsic proteins (TIPs), which typically mediate water transport across vacuolar membranes, play an essential role in plant growth, development, and stress...
BACKGROUND
Tonoplast intrinsic proteins (TIPs), which typically mediate water transport across vacuolar membranes, play an essential role in plant growth, development, and stress responses. However, their characterization in tigernut (Cyperus esculentus L.), an oil-bearing tuber plant of the Cyperaceae family, is still in the infancy.
RESULTS
In this study, a first genome-wide characterization of the TIP subfamily was conducted in tigernut, resulting in ten members representing five previously defined phylogenetic groups, i.e., TIP1-5. Although the gene amounts are equal to that present in two model plants Arabidopsis and rice, the group composition and/or evolution pattern were shown to be different. Except for CeTIP1;3 that has no counterpart in both Arabidopsis and rice, complex orthologous relationships of 1:1, 1:2, 1:3, 2:1, and 2:2 were observed. Expansion of the CeTIP subfamily was contributed by whole-genome duplication (WGD), transposed, and dispersed duplications. In contrast to the recent WGD-derivation of CeTIP3;1/-3;2, synteny analyses indicated that TIP4 and - 5 are old WGD repeats of TIP2, appearing sometime before monocot-eudicot divergence. Expression analysis revealed that CeTIP genes exhibit diverse expression profiles and are subjected to developmental and diurnal fluctuation regulation. Moreover, when transiently overexpressed in tobacco leaves, CeTIP1;1 was shown to locate in the vacuolar membrane and function in homo/heteromultimer, whereas CeTIP2;1 is located in the cell membrane and only function in heteromultimer. Interestingly, CeTIP1;1 could mediate the tonoplast-localization of CeTIP2;1 via protein interaction, implying complex regulatory patterns.
CONCLUSIONS
Our findings provide a global view of CeTIP genes, which provide valuable information for further functional analysis and genetic improvement through manipulating key members in tigernut.
Topics: Cyperus; Arabidopsis; Phylogeny; Genome; Plants; Aquaporins; Gene Expression Regulation, Plant; Plant Proteins
PubMed: 38632542
DOI: 10.1186/s12870-024-04969-x