PEX5 translocation into and out of peroxisomes drives matrix protein import.

Peroxisomes are ubiquitous organelles whose dysfunction causes fatal human diseases. Most peroxisomal enzymes are imported from the cytosol by the receptor PEX5, which interacts with a docking complex in the peroxisomal membrane and then returns to the cytosol after monoubiquitination by a membrane-embedded ubiquitin ligase. The mechanism by which PEX5 shuttles between cytosol and peroxisomes and releases cargo inside the lumen is unclear. Here, we use Xenopus egg extract to demonstrate that PEX5 accompanies cargo completely into the lumen, utilizing WxxxF/Y motifs near its N terminus that bind a lumenal domain of the docking complex. PEX5 recycling is initiated by an amphipathic helix that binds to the lumenal side of the ubiquitin ligase. The N terminus then emerges in the cytosol for monoubiquitination. Finally, PEX5 is extracted from the lumen, resulting in the unfolding of the receptor and cargo release. Our results reveal the unique mechanism by which PEX5 ferries proteins into peroxisomes.

Multiple regulatory inputs including cell envelope stress orchestrate expression of the Escherichia coli rpoN operon.

The rpoN operon, an important regulatory hub in Enterobacteriaceae, includes rpoN encoding sigma factor σ54, hpf involved in ribosome hibernation, rapZ regulating glucosamine-6-phosphate levels, and two genes encoding proteins of the nitrogen-related phosphotransferase system. Little is known about regulatory mechanisms controlling the abundance of these proteins. This study employs transposon mutagenesis and chemical screens to dissect the complex expression of the rpoN operon. We find that envelope stress conditions trigger read-through transcription into the rpoN operon from a promoter located upstream of the preceding lptA-lptB locus. This promoter is controlled by the envelope stress sigma factor E and response regulator PhoP is required for its full response to a subset of stress signals. σE also stimulates ptsN-rapZ-npr expression using an element downstream of rpoN, presumably by interfering with mRNA processing by RNase E. Additionally, we identify a novel promoter in the 3' end of rpoN that directs transcription of the distal genes in response to ethanol. Finally, we show that translation of hpf and ptsN is individually regulated by the RNA chaperone Hfq, perhaps involving small RNAs. Collectively, our work demonstrates that the rpoN operon is subject to complex regulation, integrating signals related to envelope stress and carbon source quality.

Import and quality control of peroxisomal proteins.

Peroxisomes are involved in a multitude of metabolic and catabolic pathways, as well as the innate immune system. Their dysfunction is linked to severe peroxisome-specific diseases, as well as cancer and neurodegenerative diseases. To ensure the ability of peroxisomes to fulfill their many roles in the organism, more than 100 different proteins are post-translationally imported into the peroxisomal membrane and matrix, and their functionality must be closely monitored. In this Review, we briefly discuss the import of peroxisomal membrane proteins, and we emphasize an updated view of both classical and alternative peroxisomal matrix protein import pathways. We highlight different quality control pathways that ensure the degradation of dysfunctional peroxisomal proteins. Finally, we compare peroxisomal matrix protein import with other systems that transport folded proteins across membranes, in particular the twin-arginine translocation (Tat) system and the nuclear pore.

A broadly applicable, stress-mediated bacterial death pathway regulated by the phosphotransferase system (PTS) and the cAMP-Crp cascade.

Recent work indicates that killing of bacteria by diverse antimicrobial classes can involve reactive oxygen species (ROS), as if a common, self-destructive response to antibiotics occurs. However, the ROS-bacterial death theory has been challenged. To better understand stress-mediated bacterial death, we enriched spontaneous antideath mutants of Escherichia coli that survive treatment by diverse bactericidal agents that include antibiotics, disinfectants, and environmental stressors, without a priori consideration of ROS. The mutants retained bacteriostatic susceptibility, thereby ruling out resistance. Surprisingly, pan-tolerance arose from carbohydrate metabolism deficiencies in ptsI (phosphotransferase) and cyaA (adenyl cyclase); these genes displayed the activity of upstream regulators of a widely shared, stress-mediated death pathway. The antideath effect was reversed by genetic complementation, exogenous cAMP, or a Crp variant that bypasses cAMP binding for activation. Downstream events comprised a metabolic shift from the TCA cycle to glycolysis and to the pentose phosphate pathway, suppression of stress-mediated ATP surges, and reduced accumulation of ROS. These observations reveal how upstream signals from diverse stress-mediated lesions stimulate shared, late-stage, ROS-mediated events. Cultures of these stable, pan-tolerant mutants grew normally and were therefore distinct from tolerance derived from growth defects described previously. Pan-tolerance raises the potential for unrestricted disinfectant use to contribute to antibiotic tolerance and resistance. It also weakens host defenses, because three agents (hypochlorite, hydrogen peroxide, and low pH) affected by pan-tolerance are used by the immune system to fight infections. Understanding and manipulating the PtsI-CyaA-Crp­mediated death process can help better control pathogens and maintain beneficial microbiota during antimicrobial treatment.

COL4A1-related disorder as a mimic of congenital TORCHES infection-Expanding the clinical, neuroimaging and genotype spectrum.

Pseudo-TORCH Syndrome (PTS) encompasses a heterogeneous group of genetic disorders that may clinically and radiologically resemble congenital TORCH infections. These mimickers present with overlapping features manifested as intracranial and systemic abnormalities. Collagen type IV alpha 1 chain (COL4A1)-related diseases, characterized by autosomal dominant inheritance, exhibit a diverse phenotypic spectrum involving cerebrovascular, renal, ophthalmological, cardiac, and muscular abnormalities. Cerebrovascular manifestations range from small-vessel brain disease to large vessel abnormalities, resulting in intracerebral hemorrhage, periventricular leukoencephalopathy, and ventriculomegaly. Additional features include cortical malformations, eye defects, arrhythmias, renal disease, muscular abnormalities, and hematological manifestations. Age of onset varies widely, and phenotypic variability exists even among individuals with the same variant. In this study, we present two cases of COL4A1-related disorder mimicking congenital TORCH infections, highlighting the importance of recognizing genetic mimics in clinical practice.

Characterization and engineering of peroxisome targeting sequences for compartmentalization engineering in Pichia pastoris.

Peroxisomal compartmentalization has emerged as a highly promising strategy for reconstituting intricate metabolic pathways. In recent years, significant progress has been made in the peroxisomes through harnessing precursor pools, circumventing metabolic crosstalk, and minimizing the cytotoxicity of exogenous pathways. However, it is important to note that in methylotrophic yeasts (e.g. Pichia pastoris), the abundance and protein composition of peroxisomes are highly variable, particularly when peroxisome proliferation is induced by specific carbon sources. The intricate subcellular localization of native proteins, the variability of peroxisomal metabolic pathways, and the lack of systematic characterization of peroxisome targeting signals have limited the applications of peroxisomal compartmentalization in P. pastoris. Accordingly, this study established a high-throughput screening method based on ß-carotene biosynthetic pathway to evaluate the targeting efficiency of PTS1s (Peroxisome Targeting Signal Type 1) in P. pastoris. First, 25 putative endogenous PTS1s were characterized and 3 PTS1s with high targeting efficiency were identified. Then, directed evolution of PTS1s was performed by constructing two PTS1 mutant libraries, and a total of 51 PTS1s (29 classical and 22 noncanonical PTS1s) with presumably higher peroxisomal targeting efficiency were identified, part of which were further characterized via confocal microscope. Finally, the newly identified PTS1s were employed for peroxisomal compartmentalization of the geraniol biosynthetic pathway, resulting in more than 30% increase in the titer of monoterpene compared with when the pathway was localized to the cytosol. The present study expands the synthetic biology toolkit and lays a solid foundation for peroxisomal compartmentalization in P. pastoris.

2D-3D heterostructure of PtS2-x/Ga2O3and their band alignment studies for high performance and broadband photodetector.

For deep ultraviolet (UV-C) photodetectors, gallium oxide (Ga2O3) is a suitable candidate owing to its intrinsic ultra-wide band gap and high stability. However, its detection is limited within the UV-C region, which restricts it to cover a broad range, especially in visible and near-infrared (NIR) region. Therefore, constructing a heterostructure of Ga2O3with an appropriate material having a narrow band gap is a worthwhile approach to compensate for it. In this category, PtS2group-10 transitional metal dichalcogenide stands at the top owing to its narrow band gap (0.25-1.65 eV), high mobility, and stability for heterostructure synthesis. Moreover, heterostructure with Ga2O3sensing in UV and PtS2broad response in visible and IR range can broaden the spectrum from UV to NIR and to build broadband photodetector. In this work, we fabricated a 2D-3D PtS2-x/Ga2O3heterostructure based broadband photodetector with detection from UV-C to NIR region. In addition, the PtS2-x/Ga2O3device shows a high responsivity of 38.7 AW-1and detectivity of 4.8 × 1013Jones under 1100 nm light illumination at 5 V bias. A fast response of 90 ms/86 ms illustrates the device's fast speed. An interface study between the PtS2-xand Ga2O3was conducted using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS) which confirmed type-I band alignment. Finally, based on their band alignment study, a carrier transport mechanism was proposed at the interface. This work offers a new opportunity to fabricate large-area high-performance 2D-3D heterostructures based photodetectors for future optoelectronics devices.

Construction of a Prediction Model for Post-Thrombotic Syndrome After Deep Vein Thrombosis Incorporating Novel Inflammatory Response Parameter Scoring.

OBJECTIVE: To investigate the independent predictive factors for post-thrombotic syndrome (PTS) and to construct a risk prediction model for PTS by incorporating a novel inflammatory response parameter scoring. METHODS: A retrospective study analyzed patients diagnosed with lower extremity deep vein thrombosis (LEDVT) at the Affiliated Hospital of Chengde Medical College from January 2018 to January 2022. The Villalta scale was used to assess the occurrence of PTS 6-24 months after discharge. Patients were randomly divided into a training set and a validation set at a ratio of 7:3. In the training set, univariate analysis was performed on meaningful continuous variables, and those with differences were converted into dichotomous variables based on optimal cutoff values. Variable selection was performed using Log-Lambda and LASSO 10-fold cross-validation, followed by multivariable logistic regression analysis on selected variables for model construction. The model underwent internal validation in the validation set and external validation in an independent external cohort, including discriminative analysis, calibration analysis, and clinical decision curve analysis, with the model's rationale being evaluated lastly. RESULTS: A total of 356 patients with lower extremity DVT were included, with 249 in the training set for model construction and 107 in the validation set for internal validation, along with 37 external patients for external validation. A composite score of inflammatory response parameters, including the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to high-density lipoprotein cholesterol ratio (MHR) (NLR-PLR-MHR score, NPMscore), was developed, showing a significantly higher NPMscore in the PTS group compared to the non-PTS group (p<0.05). Predictive factors related to the risk of PTS occurrence included stage (OR=6.83, 95%CI: 2.74-18.04), varicose veins (OR=7.30, 95%CI: 2.29-25.75), homocysteine (Hcy) (OR=1.12, 95%CI: 1.04-1.22), NPMscore (OR=3.13, 95%CI: 1.94-5.36), standardized anticoagulant therapy (OR=5.77, 95%CI: 1.25-27.62), and one-stop treatment (OR=0.04, 95%CI: 0.00-0.35) were incorporated into the Nomogram model. The model showed good discrimination with a concordance index of 0.918 (95%CI: 0.876-0.959) for model construction, 0.843 (95%CI: 0.741-0.945) for internal validation, and 0.823 (95%CI: 0.667-0.903) for external validation. The Nomogram model, internal and external validation calibration curves showed good agreement between observed and predicted values. Decision curve analysis (DCA) indicated the Nomogram model predicted PTS risk probability thresholds ranging from 3%-98% for model construction, 5%-97% for internal validation, and 10%-80% for external validation, demonstrating better net benefit for predicting PTS risk in the model, internal, and external validation. Rationality analysis showed the model and internal validation had higher discrimination and clinical net benefit than other clinical indices. CONCLUSION: The novel inflammatory response parameter score (NPMscore) combined with stage, varicose veins, homocysteine (Hcy), standardized anticoagulant therapy, and one-stop treatment in the Nomogram model provides a practical tool for healthcare professionals to assess the risk of PTS in DVT patients, enabling early identification of high-risk patients for effective PTS prevention.

Tyrosine phosphorylation-dependent localization of TmaR that controls activity of a major bacterial sugar regulator by polar sequestration.

The poles of Escherichia coli cells are emerging as hubs for major sensory systems, but the polar determinants that allocate their components to the pole are largely unknown. Here, we describe the discovery of a previously unannotated protein, TmaR, which localizes to the E. coli cell pole when phosphorylated on a tyrosine residue. TmaR is shown here to control the subcellular localization and activity of the general PTS protein Enzyme I (EI) by binding and polar sequestration of EI, thus regulating sugar uptake and metabolism. Depletion or overexpression of TmaR results in EI release from the pole or enhanced recruitment to the pole, which leads to increasing or decreasing the rate of sugar consumption, respectively. Notably, phosphorylation of TmaR is required to release EI and enable its activity. Like TmaR, the ability of EI to be recruited to the pole depends on phosphorylation of one of its tyrosines. In addition to hyperactivity in sugar consumption, the absence of TmaR also leads to detrimental effects on the ability of cells to survive in mild acidic conditions. Our results suggest that this survival defect, which is sugar- and EI-dependent, reflects the difficulty of cells lacking TmaR to enter stationary phase. Our study identifies TmaR as the first, to our knowledge, E. coli protein reported to localize in a tyrosine-dependent manner and to control the activity of other proteins by their polar sequestration and release.

Malrotated lateral knee radiographs do not allow for a proper assessment of medial or lateral posterior tibial slope.

PURPOSE: The aim of this study was to investigate whether malrotation of lateral knee radiographs influences posterior tibial slope (PTS) measurements. METHODS: Lateral knee radiographs of all patients who underwent knee surgery at a single institution between June 2022 and January 2023 and received multiple lateral knee radiographs were included. Radiographs were categorised as malrotated lateral knee radiographs or lateral knee radiographs based on the radiographic distance between the medial and lateral posterior femoral condyles. Medial PTS (MPTS) and lateral PTS (LPTS) were evaluated on malrotated lateral knee radiographs and lateral knee radiographs and compared using the paired t test. Intra- and interrater reliability between four raters were assessed for MPTS and LPTS measurements. RESULTS: A total of 92 lateral knee radiographs (46 pairs of malrotated lateral knee radiographs and lateral knee radiographs; 50.0% right side) from 46 patients (33.2 ± 12.4 years, 69.6% male) were included. Mean posterior femoral condyle distance in malrotated lateral knee radiographs was 8.1 ± 4.4 mm. Overall, MPTS and LPTS were significantly higher on malrotated lateral knee radiographs versus lateral knee radiographs (medial: 10.5 ± 3.2° vs. 9.7 ± 3.5°, p < 0.05; lateral: 10.6 ± 3.4° vs. 9.7 ± 3.3°, p < 0.05). Mean absolute difference between MPTS and LPTS on malrotated lateral knee radiographs versus lateral knee radiographs were |1.9| ± |1.5|° and |2.0| ± |1.8|°, respectively. Intrarater reliability was 'moderate' and interrater reliability was 'good' for both MPTS and LPTS. CONCLUSION: Malrotation of lateral knee radiographs led to a significant distortion of both the MPTS and LPTS. In clinical practice, attention should be placed on the (mal)rotation of lateral knee radiographs, especially in patients for whom a slope-correcting osteotomy is being discussed. LEVEL OF EVIDENCE: Level IV.

Glucose Phosphotransferase System Modulates Pyruvate Metabolism, Bacterial Fitness, and Microbial Ecology in Oral Streptococci.

Spontaneous mutants with defects in the primary glucose phosphotransferase permease (manLMNO) of Streptococcus sanguinis SK36 showed enhanced fitness at low pH. Transcriptomics and metabolomics with a manL deletion mutant (SK36/manL) revealed redirection of pyruvate to production of acetate and formate, rather than lactate. These observations were consistent with measurements of decreased lactic acid accumulation and increased excretion of acetate, formate, pyruvate, and H2O2. Genes showing increased expression in SK36/manL included those encoding carbohydrate transporters, extracellular glycosidases, intracellular polysaccharide metabolism, and arginine deiminase and pathways for metabolism of acetoin, ethanolamine, ascorbate, and formate, along with genes required for membrane biosynthesis and adhesion. Streptococcus mutans UA159 persisted much better in biofilm cocultures with SK36/manL than with SK36, an effect that was further enhanced by culturing the biofilms anaerobically but dampened by adding arginine to the medium. We posited that the enhanced persistence of S. mutans with SK36/manL was in part due to excess excretion of pyruvate by the latter, as addition of pyruvate to S. mutans-S. sanguinis cocultures increased the proportions of UA159 in the biofilms. Reducing the buffer capacity or increasing the concentration of glucose benefited UA159 when cocultured with SK36, but not with SK36/manL, likely due to the altered metabolism and enhanced acid tolerance of the mutant. When manL was deleted in S. mutans or Streptococcus gordonii, the mutants presented altered fitness characteristics. Our study demonstrated that phosphotransferase system (PTS)-dependent modulation of central metabolism can profoundly affect streptococcal fitness and metabolic interactions, revealing another dimension in commensal-pathogen relationships influencing dental caries development. IMPORTANCE Dental caries is underpinned by a dysbiotic microbiome and increased acid production. As beneficial bacteria that can antagonize oral pathobionts, oral streptococci such as S. sanguinis and S. gordonii can ferment many carbohydrates, despite their relative sensitivity to low pH. We characterized the molecular basis for why mutants of glucose transporter ManLMNO of S. sanguinis showed enhanced production of hydrogen peroxide and ammonia and improved persistence under acidic conditions. A metabolic shift involving more than 300 genes required for carbohydrate transport, energy production, and envelope biogenesis was observed. Significantly, manL mutants engineered in three different oral streptococci displayed altered capacities for acid production and interspecies antagonism, highlighting the potential for targeting the glucose-PTS to modulate the pathogenicity of oral biofilms.

Defining upstream enhancing and inhibiting sequence patterns for plant peroxisome targeting signal type 1 using large-scale in silico and in vivo analyses.

Peroxisomes are universal eukaryotic organelles essential to plants and animals. Most peroxisomal matrix proteins carry peroxisome targeting signal type 1 (PTS1), a C-terminal tripeptide. Studies from various kingdoms have revealed influences from sequence upstream of the tripeptide on peroxisome targeting, supporting the view that positive charges in the upstream region are the major enhancing elements. However, a systematic approach to better define the upstream elements influencing PTS1 targeting capability is needed. Here, we used protein sequences from 177 plant genomes to perform large-scale and in-depth analysis of the PTS1 domain, which includes the PTS1 tripeptide and upstream sequence elements. We identified and verified 12 low-frequency PTS1 tripeptides and revealed upstream enhancing and inhibiting sequence patterns for peroxisome targeting, which were subsequently validated in vivo. Follow-up analysis revealed that nonpolar and acidic residues have relatively strong enhancing and inhibiting effects, respectively, on peroxisome targeting. However, in contrast to the previous understanding, positive charges alone do not show the anticipated enhancing effect and that both the position and property of the residues within these patterns are important for peroxisome targeting. We further demonstrated that the three residues immediately upstream of the tripeptide are the core influencers, with a 'basic-nonpolar-basic' pattern serving as a strong and universal enhancing pattern for peroxisome targeting. These findings have significantly advanced our knowledge of the PTS1 domain in plants and likely other eukaryotic species as well. The principles and strategies employed in the present study may also be applied to deciphering auxiliary targeting signals for other organelles.

Carbon catabolite repression on the Rgg2/3 quorum sensing system in Streptococcus pyogenes is mediated by PTSMan and Mga.

Streptococcus pyogenes, also known as group A Streptococcus or GAS, is a human-restricted pathogen causing a diverse array of infections. The ability to adapt to different niches requires GAS to adjust gene expression in response to environmental cues. We previously identified the abundance of biometals and carbohydrates led to natural induction of the Rgg2/3 cell-cell communication system (quorum sensing, QS). Here we determined the mechanism by which the Rgg2/3 QS system is stimulated exclusively by mannose and repressed by glucose, a phenomenon known as carbon catabolite repression (CCR). Instead of carbon catabolite protein A, the primary mediator of CCR in Gram-positive bacteria; CCR of Rgg2/3 requires the PTS regulatory domain (PRD)-containing transcriptional regulator Mga. Deletion of Mga led to carbohydrate-independent activation of Rgg2/3 by down-regulating rgg3, the QS repressor. Through phosphoablative and phosphomimetic substitutions within Mga PRDs, we demonstrated that selective phosphorylation of PRD1 conferred repression of the Rgg2/3 system. Moreover, given the carbohydrate specificity mediating Mga-dependent governance over Rgg2/3, we tested mannose-specific PTS components and found the EIIA/B subunit ManL was required for Mga-dependent repression. These findings provide newfound connections between PTSMan , Mga, and QS, and further demonstrate that Mga is a central regulatory nexus for integrating nutritional status and virulence.

Effective Photocatalytic Ethanol Reforming into High-Value-Added Multicarbon Compound Coupled with H2 Production Over Pt-S3 Sites at PtSA -ZnIn2 S4 Interface.

Selective photocatalytic production of high-value acetaldehyde concurrently with H2 from bioethanol is an appealing approach to meet the urgent environment and energy issues. However, the difficult ethanol dehydrogenation and insufficient active sites for proton reduction within the catalysts, and the long spatial distance between these two sites always restrict their catalytic activity. Here, guided by the strong metal-substrate interaction effect, an atomic-level catalyst design strategy to construct Pt-S3 single atom on ZnIn2 S4 nanosheets (PtSA -ZIS) is demonstrated. As active center with optimized H adsorption energy to facilitate H2 evolution reaction, the unique Pt single atom also donates electrons to its neighboring S atoms with electron-enriched sites formed to activate the O─H bond in * CH3 CHOH and promote the desorption of * CH3 CHO. Thus, the synergy between Pt single atom and ZIS together will reduce the energy barrier for the ethanol oxidization to acetaldehyde, and also narrow the spatial distance for proton mass transfer. These features enable PtSA -ZIS photocatalyst to produce acetaldehyde with a selectivity of ≈100%, which will spontaneously transform into 1,1-diethoxyethane via acetalization to avoid volatilization. Meanwhile, a remarkable H2 evolution rate (184.4 µmol h-1 ) is achieved with a high apparent quantum efficiency of 10.50% at 400 nm.

Determining the targeting specificity of the selective peroxisomal targeting factor Pex9.

Accurate and regulated protein targeting is crucial for cellular function and proteostasis. In the yeast Saccharomyces cerevisiae, peroxisomal matrix proteins, which harboring a Peroxisomal Targeting Signal 1 (PTS1), can utilize two paralog targeting factors, Pex5 and Pex9, to target correctly. While both proteins are similar and recognize PTS1 signals, Pex9 targets only a subset of Pex5 cargo proteins. However, what defines this substrate selectivity remains uncovered. Here, we used unbiased screens alongside directed experiments to identify the properties underlying Pex9 targeting specificity. We find that the specificity of Pex9 is largely determined by the hydrophobic nature of the amino acid preceding the PTS1 tripeptide of its cargos. This is explained by structural modeling of the PTS1-binding cavities of the two factors showing differences in their surface hydrophobicity. Our work outlines the mechanism by which targeting specificity is achieved, enabling dynamic rewiring of the peroxisomal proteome in changing metabolic needs.

DegU-mediated suppression of carbohydrate uptake in Listeria monocytogenes increases adaptation to oxidative stress.

The foodborne bacterial pathogen Listeria monocytogenes exhibits remarkable survival capabilities under challenging conditions, severely threatening food safety and human health. The orphan regulator DegU is a pleiotropic regulator required for bacterial environmental adaptation. However, the specific mechanism of how DegU participates in oxidative stress tolerance remains unknown in L. monocytogenes. In this study, we demonstrate that DegU suppresses carbohydrate uptake under stress conditions by altering global transcriptional profiles, particularly by modulating the transcription of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS)-related genes, such as ptsH, ptsI, and hprK. Specifically, in the absence of degU, the transcripts of ptsI are significantly upregulated and those of hprK are significantly downregulated in response to copper ion-induced stress. Overexpression of ptsI significantly increases bacterial growth in vitro, while overexpression of hprK leads to a decrease in growth. We further demonstrate that DegU directly senses oxidative stress, downregulates ptsI transcription, and upregulates hprK transcription. Additionally, through an electrophoretic mobility shift assay, we demonstrate that DegU directly regulates the transcription of ptsI and hprK by binding to specific regions within their respective promoter sequences. Notably, the putative pivotal DegU binding sequence for ptsI is located from 38 to 68 base pairs upstream of the ptsH transcription start site (TSS), whereas for hprK, it is mapped from 36 to 124 base pairs upstream of the hprK TSS. In summary, we elucidate that DegU plays a significant role in suppressing carbohydrate uptake in response to oxidative stress through the direct regulation of ptsI and hprK.ImportanceUnderstanding the adaptive mechanisms employed by Listeria monocytogenes in harsh environments is of great significance. This study focuses on investigating the role of DegU in response to oxidative stress by examining global transcriptional profiles. The results highlight the noteworthy involvement of DegU in this stress response. Specifically, DegU acts as a direct sensor of oxidative stress, leading to the modulation of gene transcription. It downregulates ptsI transcription while it upregulates hprK transcription through direct binding to their promoters. Consequently, these regulatory actions impede bacterial growth, providing a defense mechanism against stress-induced damage. These findings gained from this study may have broader implications, serving as a reference for studying adaptive mechanisms in other pathogenic bacteria and aiding in the development of targeted strategies to control L. monocytogenes and ensure food safety.

Structural Basis of the Mechanisms of Action and Immunity of Lactococcin A, a Class IId Bacteriocin.

Lactococcin A (LcnA), a class IId bacteriocin, induces membrane leakage and cell death by specifically binding to the membrane receptor-mannose phosphotransferase system (man-PTS), as is the case for pediocin-like (class IIa) bacteriocins. The cognate immunity protein of bacteriocins, which protects the producer cell from its own bacteriocin, recognizes and binds to the bacteriocin-man-PTS complex, consequently blocking membrane leakage. We previously deciphered the mode of action and immunity of class IIa bacteriocins. Here, we determined the structure of the ternary complex of LcnA, LciA (i.e., the immunity protein), and its receptor, i.e., the man-PTS of Lactococcus lactis (ll-man-PTS). An external loop on the membrane-located component IIC of ll-man-PTS was found to prevent specific binding of the N-terminal region of LcnA to the site recognized by pediocin-like bacteriocins. Thus, the N-terminal ß-sheet region of LcnA recognized an adjacent site on the extracellular side of ll-man-PTS, with the LcnA C-terminal hydrophobic helix penetrating into the membrane. The cytoplasmic cleft formed within the man-PTS Core and Vmotif domains induced by embedded LcnA from the periplasmic side is adopted by the appropriate angle between helices H3 and H4 of the N terminus of LciA. The flexible C terminus of LciA then blocks membrane leakage. To summarize, our findings reveal the molecular mechanisms of action and immunity of LcnA and LciA, laying a foundation for further design of class IId bacteriocins. IMPORTANCE Class IId (lactococcin-like) bacteriocins and class IIa (pediocin-like) bacteriocins share a few similarities: (i) both induce membrane leakage and cell death by specifically binding the mannose phosphotransferase system (man-PTS) on their target cells, and (ii) cognate immunity proteins recognize and bind to the bacteriocin-man-PTS complex to block membrane leakage. However, class IId bacteriocins lack the "pediocin box" motif, which is typical of class IIa bacteriocins, and basically target only lactococcal cells; in contrast, class IIa bacteriocins target diverse bacterial cells, but not lactococcal cells. We previously solved the structure of class IIa bacteriocin-receptor-immunity ternary complex from Lactobacillus sakei. Here, we determined the structure of the ternary complex of class IId bacteriocin LcnA, its cognate immunity protein LciA, and its receptor, the man-PTS of Lactococcus lactis. By comparing the interactions between man-PTS and class IIa and class IId bacteriocins, this study affords some clues to better understand the specificity of bacteriocins targeting the mannose phosphotransferase system.

Noninvasive and invasive imaging of lower-extremity acute and chronic venous thrombotic disease.

The spectrum of venous thromboembolic (VTE) disease encompasses both acute deep venous thrombosis (DVT) and chronic postthrombotic changes (CPC). A large percentage of acute DVT patients experience recurrent VTE despite adequate anticoagulation, and may progress to CPC. Further, the role of iliocaval venous obstruction (ICVO) in lower-extremity VTE has been increasingly recognized in recent years. Imaging continues to play an important role in both acute and chronic venous disease. Venous duplex ultrasound remains the gold standard for diagnosing acute VTE. However, imaging of CPC is more complex and may involve computed tomography, magnetic resonance, contrast-enhanced ultrasound, or intravascular ultrasound. In this narrative review, we aim to discuss the full spectrum of venous disease imaging for both acute and chronic venous thrombotic disease.

The effect of posterior tibial slope on anteroposterior stability in posterior cruciate retaining total knee arthroplasty.

BACKGROUND: It has been suggested that the posterior tibial slope (PTS) plays an important role in increasing the anteroposterior stability following total knee arthroplasty. Although the relationship between the PTS and the flexion range has been investigated many times, studies on the relationship between PTS and anterior-posterior stability are limited. The primary aim of this study was to investigate the relationship and effects of PTS on anteroposterior stability in posterior cruciate retainer total knee arthroplasty. METHODS: 154 primary TKAs were identified retrospectively to analyze the any association between PTS and anteroposterior laxity following posterior cruciate-retaining total knee arthroplasty in the overall study populations. Anteroposterior displacement was measured at the final follow-up based on the following two procedures: KT-1000 arthrometer and sagittal drawer radiographic images. In addition, the relationship between PTS and functional scores-ROM was examined. RESULTS: There was no correlation between patients' posterior tibial slope and postoperative VAS (r: -0.060, p:0.544), WOMAC (r:0.037, p:0.709), KSS (r: -0.073, p:0.455). In addition, there was no significant correlation between postoperative knee ROM and postoperative PTS (r:0.159, p:0.106). Moreover, no correlation was found between KT-1000 arthrometer and 20 degrees AP translation with PTS. There was a negative correlation between PTS and 70 degrees AP translation (r: -0.281, p:0.008). CONCLUSIONS: This study aimed to clarify the association between instability and AP laxity in flexion of implanted knees, and to determine what degree of AP laxity results of instability. A fundamental finding of this study was that; the optimum TS angle to increase anterior-posterior stability after total knee arthroplasty is between ≥ 4 to < 6 degrees, we also proved that there is no relationship between stability and patient satisfaction.

The role of maternal trauma and discipline types in emotional processing among Syrian refugee children.

Stressful experiences in armed conflict incur intergenerational effects through parental behaviors with their children. A recent study reported that among Syrian refugee families, mothers' (but not fathers') post-traumatic stress (PTS) impacted children's emotional processing. In this study, we aim to shed further light on this phenomenon by analyzing how the parenting practices in the context of post-traumatic stress confers protection or risk for children's emotional processing. Participants were 6-18-year-old children (n = 212) and their mothers (n = 94), who fled from Syria and were residing in Turkish communities. We used the computer-based emotional processing task including photos of facial movements typically associated with different emotions to measure children's capacity for emotional processing. Mothers reported their PTS and the discipline types they use, as well as the contextual factors related to their refugee background. Linear mixed effect models were constructed first, to find out the discipline types that are most strongly associated with emotional processing of the child, and second, to examine whether these discipline types moderate the effect of maternal PTS on children's emotional processing. Finally, generalized linear models were constructed to examine which contextual factors are associated with the use of these discipline types by mothers. We found that spanking as a discipline type was associated with poorer child emotional processing, whereas withholding of media access was associated with better emotional processing. Younger and less religious mothers were more prone to use spanking. The study underlines the need for parenting programs alongside with efforts to address mental health issues among mothers living under armed conflict.