A conserved zinc-binding site in Acinetobacter baumannii PBP2 required for elongasome-directed bacterial cell shape.

Acinetobacter baumannii is a gram-negative bacterial pathogen that causes challenging nosocomial infections. ß-lactam targeting of penicillin-binding protein (PBP)-mediated cell wall peptidoglycan (PG) formation is a well-established antimicrobial strategy. Exposure to carbapenems or zinc (Zn)-deprived growth conditions leads to a rod-to-sphere morphological transition in A. baumannii, an effect resembling that caused by deficiency in the RodA-PBP2 PG synthesis complex required for cell wall elongation. While it is recognized that carbapenems preferentially acylate PBP2 in A. baumannii and therefore block the transpeptidase function of the RodA-PBP2 system, the molecular details underpinning cell wall elongation inhibition upon Zn starvation remain undefined. Here, we report the X-ray crystal structure of A. baumannii PBP2, revealing an unexpected Zn coordination site in the transpeptidase domain required for protein stability. Mutations in the Zn-binding site of PBP2 cause a loss of bacterial rod shape and increase susceptibility to ß-lactams, therefore providing a direct rationale for cell wall shape maintenance and Zn homeostasis in A. baumannii. Furthermore, the Zn-coordinating residues are conserved in various ß- and γ-proteobacterial PBP2 orthologs, consistent with a widespread Zn-binding requirement for function that has been previously unknown. Due to the emergence of resistance to virtually all marketed antibiotic classes, alternative or complementary antimicrobial strategies need to be explored. These findings offer a perspective for dual inhibition of Zn-dependent PG synthases and metallo-ß-lactamases by metal chelating agents, considered the most sought-after adjuvants to restore ß-lactam potency against gram-negative bacteria.

Evaluation of the characteristics of root canal calcification after regenerative endodontic procedures: A retrospective cohort study over 3 years.

AIM: This study aimed to evaluate the characteristics of root canal calcification after regenerative endodontic procedures (REPs) during long-term follow-up. DESIGN: Data of children who underwent REPs and were followed up for >3 years in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing, China, from January 2013 to January 2019, were collected. All the patients were treated by the protocol of REPs based on the American Association of Endodontists (AAE) protocol. A total of 91 teeth of 54 boys and 37 girls (average age 10.4 ± 1.9 years) with follow-up duration >3 years were included. The follow-up duration ranged from 36 to 92 months (average, 53.2 ± 13.4 months). The prevalence, contributing factors, and long-term prognoses of root canal calcification after REPs are discussed. Independent t-test and χ2 test were used for statistical analysis. RESULTS: The incidence of root canal calcification was 78% (71/91). The use of calcium hydroxide paste was significantly correlated with the occurrence of root canal calcification (p < .05). Some teeth showed aggravation of calcification with time; however, not all teeth showed calcification after longer follow-up duration. CONCLUSIONS: Teeth treated with REPs had a relatively high probability of root canal calcification detection during the long-term follow-up. The occurrence of calcification is related to the use of calcium hydroxide paste but does not affect the long-term prognosis of teeth.

Effect of subfreezing storage on the qualities of dough and bread containing pea protein.

BACKGROUND: In this paper, -6, -9 and -12 °C were selected as subfreezing temperatures of dough containing pea protein based on the results of low-field nuclear magnetic relaxation time. The effect of storage at subfreezing temperatures on dough properties was then investigated and compared with sample storage at -18 °C. RESULTS: The pH value, springiness, resilience, cohesiveness of dough and sensory score of bread gradually decreased and the hardness and water loss rate of dough gradually increased with the extension of storage time. However, dough hardness, viscoelasticity and fermentation volume were maintained more effectively in subfreezing storage than in -18 °C storage. The subfreezing temperature could alleviate the damage of gluten network structure in frozen dough by ice crystals and was beneficial in maintaining the elasticity of gluten proteins. The network system of pea protein, gluten protein and starch granules in dough storage at -9 and -12 °C was more tightly connected and the microstructure was similar to that at -18 °C. There was no significant difference between the quality of bread made from the dough stored at subfreezing temperature and that stored at -18 °C for 1-6 weeks, and the preservation effect at -12 °C was closer to that at -18 °C. CONCLUSION: Subfreezing storage can keep the stability of dough containing pea protein close to traditional frozen storage (-18 °C), which provides a new method for storage and transportation of frozen dough. © 2022 Society of Chemical Industry.

Essential Gene Analysis in Acinetobacter baumannii by High-Density Transposon Mutagenesis and CRISPR Interference.

Acinetobacter baumannii is a poorly understood bacterium capable of life-threatening infections in hospitals. Few antibiotics remain effective against this highly resistant pathogen. Development of rationally designed antimicrobials that can target A. baumannii requires improved knowledge of the proteins that carry out essential processes allowing growth of the organism. Unfortunately, studying essential genes has been challenging using traditional techniques, which usually require time-consuming recombination-based genetic manipulations. Here, we performed saturating mutagenesis with dual transposon systems to identify essential genes in A. baumannii, and we developed a CRISPR interference (CRISPRi) system for facile analysis of these genes. We show that the CRISPRi system enables efficient transcriptional silencing in A. baumannii. Using these tools, we confirmed the essentiality of the novel cell division protein AdvA and discovered a previously uncharacterized AraC family transcription factor (ACX60_RS03245) that is necessary for growth. In addition, we show that capsule biosynthesis is a conditionally essential process, with mutations in late-acting steps causing toxicity in strain ATCC 17978 that can be bypassed by blocking early-acting steps or activating the BfmRS stress response. These results open new avenues for analysis of essential pathways in A. baumannii. IMPORTANCE New approaches are urgently needed to control A. baumannii, one of the most drug-resistant pathogens known. To facilitate the development of novel targets that allow inhibition of the pathogen, we performed a large-scale identification of genes whose products the bacterium needs for growth. We also developed a CRISPR-based gene knockdown tool that operates efficiently in A. baumannii, allowing rapid analysis of these essential genes. We used these methods to define multiple processes vital to the bacterium, including a previously uncharacterized gene regulatory factor and export of a protective polymeric capsule. These tools will enhance our ability to investigate processes critical for the essential biology of this challenging hospital-acquired pathogen.

The classification of feeding and eating disorders in the ICD-11: results of a field study comparing proposed ICD-11 guidelines with existing ICD-10 guidelines.

BACKGROUND: The World Health Organization (WHO) International Classification of Diseases and Related Health Problems (ICD) is used globally by 194 WHO member nations. It is used for assigning clinical diagnoses, providing the framework for reporting public health data, and to inform the organization and reimbursement of health services. Guided by overarching principles of increasing clinical utility and global applicability, the 11th revision of the ICD proposes major changes that incorporate empirical advances since the previous revision in 1992. To test recommended changes in the Mental, Behavioral, and Neurodevelopmental Disorders chapter, multiple vignette-based case-controlled field studies have been conducted which examine clinicians' ability to accurately and consistently use the new guidelines and assess their overall clinical utility. This manuscript reports on the results from the study of the proposed ICD-11 guidelines for feeding and eating disorders (FEDs). METHOD: Participants were 2288 mental health professionals registered with WHO's Global Clinical Practice Network. The study was conducted in Chinese, English, French, Japanese, and Spanish. Clinicians were randomly assigned to apply either the ICD-11 or ICD-10 diagnostic guidelines for FEDs to a pair of case vignettes designed to test specific clinical questions. Clinicians selected the diagnosis they thought was correct for each vignette, evaluated the presence of each essential feature of the selected diagnosis, and the clinical utility of the diagnostic guidelines. RESULTS: The proposed ICD-11 diagnostic guidelines significantly improved accuracy for all FEDs tested relative to ICD-10 and attained higher clinical utility ratings; similar results were obtained across all five languages. The inclusion of binge eating disorder and avoidant-restrictive food intake disorder reduced the use of residual diagnoses. Areas needing further refinement were identified. CONCLUSIONS: The proposed ICD-11 diagnostic guidelines consistently outperformed ICD-10 in distinguishing cases of eating disorders and showed global applicability and appropriate clinical utility. These results suggest that the proposed ICD-11 guidelines for FEDs will help increase accuracy of public health data, improve clinical diagnosis, and enhance health service organization and provision. This is the first time in the revision of the ICD that data from large-scale, empirical research examining proposed guidelines is completed in time to inform the final diagnostic guidelines.

Co-morbidity of personality disorder in schizophrenia among psychiatric outpatients in China: data from epidemiologic survey in a clinical population.

BACKGROUND: The reported rates of personality disorder (PD) in subjects with schizophrenia (SZ) are quite varied across different countries, and less is known about the heterogeneity of PD among subjects with SZ. We examined the co-morbidity of PD among patients who are in the stable phase of SZ. METHOD: 850 subjects were randomly sampled from patients diagnosed with SZ in psychiatric and psycho-counseling clinics at Shanghai Mental Health Center. Co-morbidity of PDs was assessed through preliminary screening and patients were administered several modules of the SCID-II. Evidence of heterogeneity was evaluated by comparing patients diagnosed with SZ with those who presented with either affective disorder or neurosis (ADN). RESULTS: 204 outpatients (24.0 %) in the stable phase of SZ met criteria for at least one type of DSM-IV PD. There was a higher prevalence of Cluster-A (odd and eccentric PD) and C (anxious and panic PD) PDs in SZ (around 12.0 %). The most prevalent PD was the paranoid subtype (7.65 %). Subjects with SZ were significantly more likely to have schizotypal PD (4.4 % vs. 2.1 %, p = 0.003) and paranoid PD (7.6 % vs. 5.4 %, p = 0.034), but much less likely to have borderline, obsessive-compulsive, depressive, narcissistic and histrionic PD. CONCLUSIONS: These findings suggest that DSM-IV PD is common in patients with SZ than in the general population. Patterns of co-morbidity with PDs in SZ are different from ADN.

Combination of bulk RNA sequencing and scRNA sequencing uncover the molecular characteristics of MAPK signaling in kidney renal clear cell carcinoma.

The MAPK signaling pathway significantly impacts cancer progression and resistance; however, its functions remain incompletely assessed across various cancers, particularly in kidney renal clear cell carcinoma (KIRC). Therefore, there is an urgent need for comprehensive pan-cancer investigations of MAPK signaling, particularly within the context of KIRC. In this research, we obtained TCGA pan-cancer multi-omics data and conducted a comprehensive analysis of the genomic and transcriptomic characteristics of the MAPK signaling pathway. For in-depth investigation in KIRC, status of MAPK pathway was quantitatively estimated by ssGSEA and Ward algorithm was utilized for cluster analysis. Molecular characteristics and clinical prognoses of KIRC patients with distinct MAPK activities were comprehensively explored using a series of bioinformatics algorithms. Subsequently, a combination of LASSO and COX regression analyses were utilized sequentially to construct a MAPK-related signature to help identify the risk level of each sample. Patients in the C1 subtype exhibited relatively higher levels of MAPK signaling activity, which were associated with abundant immune cell infiltration and favorable clinical outcomes. Single-cell RNA sequencing (scRNA-seq) analysis of KIRC samples identified seven distinct cell types, and endothelial cells in tumor tissues had obviously higher MAPK scores than normal tissues. The immunohistochemistry results indicated the reduced expression levels of PAPSS1, MAP3K11, and SPRED1 in KIRC samples. In conclusion, our study represents the first integration of bulk RNA sequencing and single-cell RNA sequencing to elucidate the molecular characteristics of MAPK signaling in KIRC, providing a solid foundation for precision oncology.

A phosphorylation signal activates genome-wide transcriptional control by BfmR, the global regulator of Acinetobacter resistance and virulence.

The nosocomial pathogen Acinetobacter baumannii is a major threat to human health. The sensor kinase-response regulator system, BfmS-BfmR, is essential to multidrug resistance and virulence in the bacterium and represents a potential antimicrobial target. Important questions remain about how the system controls resistance and pathogenesis. Although BfmR knockout alters expression of >1000 genes, its direct regulon is undefined. Moreover, how phosphorylation controls the regulator is unclear. Here, we address these problems by combining mutagenesis, ChIP-seq, and in vitro phosphorylation to study the functions of phospho-BfmR. We show that phosphorylation is required for BfmR-mediated gene regulation, antibiotic resistance, and sepsis development in vivo. Consistent with activating the protein, phosphorylation induces dimerization and target DNA affinity. Integrated analysis of genome-wide binding and transcriptional profiles of BfmR led to additional key findings: (1) Phosphorylation dramatically expands the number of genomic sites BfmR binds; (2) DNA recognition involves a direct repeat motif widespread across promoters; (3) BfmR directly regulates 303 genes as activator (eg, capsule, peptidoglycan, and outer membrane biogenesis) or repressor (pilus biogenesis); (4) BfmR controls several non-coding sRNAs. These studies reveal the centrality of a phosphorylation signal in driving A. baumannii disease and disentangle the extensive pathogenic gene-regulatory network under its control.

Deep learning fusion framework for automated coronary artery disease detection using raw heart sound signals.

One of the most common cardiovascular diseases is coronary artery disease (CAD). Thus, it is crucial for early CAD diagnosis to control disease progression. Computer-aided CAD detection often converts heart sounds into graphics for analysis. However, this method relies heavily on the subjective experience of experts. Therefore, in this study, we proposed a method for CAD detection using raw heart sound signals by constructing a fusion framework with two CAD detection models: a multidomain feature model and a medical multidomain feature fusion model. We collected heart sound signal datasets from 400 participants, extracting 206 multidomain features and 126 medical multidomain features. The designed framework fused the same one-dimensional deep learning features with different multidomain features for CAD detection. The experimental results showed that the multidomain feature model and the medical multidomain feature fusion model achieved areas under the curve (AUC) of 94.7 % and 92.7 %, respectively, demonstrating the effectiveness of the fusion framework in integrating one-dimensional and cross-domain heart sound features through deep learning algorithms, providing an effective solution for noninvasive CAD detection.

Effects of chia seed gum on the physicochemical properties of frozen dough and the quality of dumplings.

This study was designed to investigate the properties of chia seed gum (CSG) and its use in frozen dough. The CSG prepared by vacuum freeze-drying had the lowest water separation (4.22 ± 0.11 %) after three freeze-thaw cycles and the best color among the samples. The addition of 0.4 % to 1.0 % CSG significantly increased the peak, trough and final viscosity and decreased the breakdown and setback of the flour. The water absorption and cooking stability of the dough increased with increasing CSG content. The addition of 0.8 %-1.0 % CSG significantly increased the content of strongly bound water in dough during frozen storage. The CSG improved the texture of dough, and there were no significant differences in hardness, springiness, cohesiveness or chewiness of dough with 0.8 %-1.0 % CSG during frozen storage for 30 days. The cooking loss rate and the cracking rate of the dumpling wrappers with 0.8 % CSG were reduced by 2.31 % and 21.34 %, respectively. In conclusion, CSG can be used to improve the quality of wheat dough and its products and has promising applications in flour products.

Role of childhood traumatic experience in personality disorders in China.

BACKGROUND: There has been no large-scale examination of the association between types of childhood abuse and personality disorders (PDs) in China using standardized assessment tools and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Hence, this study aimed to explore the relationship between retrospective reports of various types of childhood maltreatments and current DSM-IV PDs in a clinical population in China, Shanghai. METHOD: One thousand four hundred two subjects were randomly sampled from the Shanghai Psychological Counselling Centre. PDs were assessed using the Personality Diagnostic Questionnaire, Fourth Edition Plus. Participants were also interviewed using the Structured Clinical Interview for DSM-IV axis II. The Child Trauma Questionnaire (CTQ) was used to assess childhood maltreatment in 5 domains (emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect). RESULTS: According to Pearson correlations, childhood maltreatment had a strong association with most PDs. Subsequently, using partial correlations, significant relationships were also demonstrated between cluster B PDs and all the traumatic factors except physical neglect. A strongest positive correlation was found between cluster B PD and CTQ total scores (r = .312, P < .01). Using the Kruskal-Wallis rank sum test, significant differences in 4 groups of subjects (clusters A, B, and C PD and non-PD) in terms of emotional abuse (χ(2) = 34.864, P < .01), physical abuse (χ(2) = 14.996, P < .05), sex abuse (χ(2) = 9.211, P < .05), and emotional neglect (χ(2) = 17.987, P < .01) were found. Stepwise regression analysis indicated that emotional abuse and emotional neglect were predictive for clusters A and B PD, and sexual abuse was highly predictive for cluster B PD; only emotional neglect was predictive for cluster C PD. CONCLUSION: Early traumatic experiences are strongly related to the development of PDs. The effects of childhood maltreatment in the 3 clusters of PDs are different. Childhood trauma has the most significant impact on cluster B PD.

Prevalence of personality disorders using two diagnostic systems in psychiatric outpatients in Shanghai, China: a comparison of uni-axial and multi-axial formulation.

OBJECTIVE: To compare multi-axial (DSM-IV) with uni-axial diagnostic system (CCMD-3, Chinese Classification and Diagnostic Criteria of Mental Disorders) as diagnostic methods to determine the prevalence of personality disorders (PDs) in Chinese psychiatric outpatients. METHOD: 3,075 outpatients were randomly sampled from clinical settings in China. CCMD-3 PDs were evaluated as per routine psychiatric practice. DSM-IV PDs were assessed using both self-reported questionnaire and structured clinical interview. RESULTS: The prevalence estimate for any type of PD in the total sample is 31.93% as reflected in the DSM-IV. This figure is nearly 110 times as large as the prevalence estimate for the CCMD-3. Only 9 outpatients were diagnosed with PD based on the CCMD-3. Amongst the 10 forms of DSM-IV PDs, avoidant (8.1%), obsessive-compulsive (7.6%), paranoid (6.0%), and borderline (5.8%) PDs were the most prevalent subtypes. This study found that PDs are commonly associated with the following: (i) the younger aged; (ii) single marital status; (iii) those who were not raised by their parents; (iv) introverted personalities; (v) first-time seekers of psycho-counseling treatment; and (vi) patients with co-morbid mood or anxiety disorders. CONCLUSIONS: PDs are easily overlooked when the diagnosis is made based on the CCMD-3 uni-axial diagnostic system. However, it was found that personality pathology is common in the Chinese psychiatric community when using the DSM-IV classification system. Existing evidence suggest, at least indirectly, that there are important benefits of moving towards a multi-axial diagnostic approach in psychiatric practice.

Aggregation properties and structure of chia seed gum and gluten protein mixtures after freezing storage.

Chia seed gum (CSG) plays an important role in the aggregation and structural properties of gluten protein. The experimental results showed that adding 1.0 % CSG increased the freezing rate and shortened the freezing time by 42.3 % compared with gluten without CSG. At the same time, CSG had no significant effect on the composition of the gluten subunit but could better control the change in binding water and delay the structural deterioration caused by the extension of time (30 d). The viscoelasticity of gluten was increased, but only with the addition of 0.2-0.6 % CSG. In addition, it increased the denaturation transition temperature (Tp) and the degradation temperature (Td) of gluten protein to reduce the occurrence of recrystallization and resist pyrolysis. During frozen storage, gluten can form fine ice crystals and inhibit the transformation of α-helices and ß-turns to random coils and ß-sheets, which is more conducive to long-term frozen storage.

A New Class of Cell Wall-Recycling l,d-Carboxypeptidase Determines ß-Lactam Susceptibility and Morphogenesis in Acinetobacter baumannii.

The hospital-acquired pathogen Acinetobacter baumannii possesses a complex cell envelope that is key to its multidrug resistance and virulence. The bacterium, however, lacks many canonical enzymes that build the envelope in model organisms. Instead, A. baumannii contains a number of poorly annotated proteins that may allow alternative mechanisms of envelope biogenesis. We demonstrated previously that one of these unusual proteins, ElsL, is required for maintaining a characteristic short rod shape and for withstanding antibiotics that attack the septal cell wall. Curiously, ElsL is composed of a leaderless YkuD-family domain usually found in secreted, cell wall-modifying l,d-transpeptidases (LDTs). Here, we show that, rather than being an LDT, ElsL is actually a new class of cytoplasmic l,d-carboxypeptidase (LDC) that provides a critical step in cell wall recycling previously thought to be missing from A. baumannii. Absence of ElsL impairs cell wall integrity, morphology, and intrinsic resistance due to buildup of murein tetrapeptide precursors, toxicity of which is bypassed by preventing muropeptide recycling. Multiple pathways in the cell become sites of vulnerability when ElsL is inactivated, including l,d-cross-link formation, cell division, and outer membrane lipid homoeostasis, reflecting its pleiotropic influence on envelope physiology. We thus reveal a novel class of cell wall-recycling LDC critical to growth and homeostasis of A. baumannii and likely many other bacteria. IMPORTANCE To grow efficiently, resist antibiotics, and control the immune response, bacteria recycle parts of their cell wall. A key step in the typical recycling pathway is the reuse of cell wall peptides by an enzyme known as an l,d-carboxypeptidase (LDC). Acinetobacter baumannii, an "urgent-threat" pathogen causing drug-resistant sepsis in hospitals, was previously thought to lack this enzymatic activity due to absence of a known LDC homolog. Here, we show that A. baumannii possesses this activity in the form of an enzyme class not previously associated with cell wall recycling. Absence of this protein intoxicates and weakens the A. baumannii cell envelope in multiple ways due to the accumulation of dead-end intermediates. Several other organisms of importance to health and disease encode homologs of the A. baumannii enzyme. This work thus reveals an unappreciated mechanism of cell wall recycling, manipulation of which may contribute to enhanced treatments targeting the bacterial envelope.

Dissociative disorders among Chinese inpatients diagnosed with schizophrenia.

The purpose of this study was to assess the prevalence of dissociative disorders in a sample of Chinese psychiatric inpatients. Participants in the study were 569 consecutively admitted inpatients at Shanghai Mental Health Center, China, of whom 84.9% had a clinical diagnosis of schizophrenia based on the Chinese Classification and Diagnostic Criteria of Mental Disorders, Version 3. All participants completed a self-report measure of dissociation (the Dissociative Experiences Scale), and none had a prior diagnosis of a dissociative disorder. A total of 96 randomly selected participants were interviewed with a structured interview (the Dissociative Disorders Interview Schedule) and a clinical interview. These 96 patients did not differ significantly from the 473 patients who were not interviewed on any demographic measures or who did not complete the self-report dissociation measure. A total of 28 patients (15.3%, after weighting of the data) received a clinical diagnosis of a dissociative disorder based on Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) criteria. Dissociative identity disorder was diagnosed in 2 patients (0.53%, after weighting). Compared to the patients without a dissociative disorder, patients with dissociative disorders were significantly more likely to report childhood abuse (57.1% vs. 22.1%), but the 2 groups did not differ significantly on any demographic measures. Dissociative disorders were readily identified in an inpatient psychiatric population in China.

BDNF-TrkB and proBDNF-p75NTR/Sortilin Signaling Pathways are Involved in Mitochondria-Mediated Neuronal Apoptosis in Dorsal Root Ganglia after Sciatic Nerve Transection.

BACKGROUND: Brain-Derived Neurotrophic Factor (BDNF) plays critical roles during development of the central and peripheral nervous systems, as well as in neuronal survival after injury. Although proBDNF induces neuronal apoptosis after injury in vivo, whether it can also act as a death factor in vitro and in vivo under physiological conditions and after nerve injury, as well as its mechanism of inducing apoptosis, is still unclear. OBJECTIVE: In this study, we investigated the mechanisms by which proBDNF causes apoptosis in sensory neurons and Satellite Glial Cells (SGCs) in Dorsal Root Ganglia (DRG) After Sciatic Nerve Transection (SNT). METHODS: SGCs cultures were prepared and a scratch model was established to analyze the role of proBDNF in sensory neurons and SGCs in DRG following SNT. Following treatment with proBDNF antiserum, TUNEL and immunohistochemistry staining were used to detect the expression of Glial Fibrillary Acidic Protein (GFAP) and Calcitonin Gene-Related Peptide (CGRP) in DRG tissue; immunocytochemistry and Cell Counting Kit-8 (CCK8) assay were used to detect GFAP expression and cell viability of SGCs, respectively. RT-qPCR, western blot, and ELISA were used to measure mRNA and protein levels, respectively, of key factors in BDNF-TrkB, proBDNF-p75NTR/sortilin, and apoptosis signaling pathways. RESULTS: proBDNF induced mitochondrial apoptosis of SGCs and neurons by modulating BDNF-TrkB and proBDNF-p75NTR/sortilin signaling pathways. In addition, neuroprotection was achieved by inhibiting the biological activity of endogenous proBDNF protein by injection of anti-proBDNF serum. Furthermore, the anti-proBDNF serum inhibited the activation of SGCs and promoted their proliferation. CONCLUSION: proBDNF induced apoptosis in SGCs and sensory neurons in DRG following SNT. The proBDNF signaling pathway is a potential novel therapeutic target for reducing sensory neuron and SGCs loss following peripheral nerve injury.

Author Correction: Antibiotic susceptibility signatures identify potential antimicrobial targets in the Acinetobacter baumannii cell envelope.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20098-z.

Antibiotic susceptibility signatures identify potential antimicrobial targets in the Acinetobacter baumannii cell envelope.

A unique, protective cell envelope contributes to the broad drug resistance of the nosocomial pathogen Acinetobacter baumannii. Here we use transposon insertion sequencing to identify A. baumannii mutants displaying altered susceptibility to a panel of diverse antibiotics. By examining mutants with antibiotic susceptibility profiles that parallel mutations in characterized genes, we infer the function of multiple uncharacterized envelope proteins, some of which have roles in cell division or cell elongation. Remarkably, mutations affecting a predicted cell wall hydrolase lead to alterations in lipooligosaccharide synthesis. In addition, the analysis of altered susceptibility signatures and antibiotic-induced morphology patterns allows us to predict drug synergies; for example, certain beta-lactams appear to work cooperatively due to their preferential targeting of specific cell wall assembly machineries. Our results indicate that the pathogen may be effectively inhibited by the combined targeting of multiple pathways critical for envelope growth.

The Landscape of Phenotypic and Transcriptional Responses to Ciprofloxacin in Acinetobacter baumannii: Acquired Resistance Alleles Modulate Drug-Induced SOS Response and Prophage Replication.

The emergence of fluoroquinolone resistance in nosocomial pathogens has restricted the clinical efficacy of this antibiotic class. In Acinetobacter baumannii, the majority of clinical isolates now show high-level resistance due to mutations in gyrA (DNA gyrase) and parC (topoisomerase IV [topo IV]). To investigate the molecular basis for fluoroquinolone resistance, an exhaustive mutation analysis was performed in both drug-sensitive and -resistant strains to identify loci that alter ciprofloxacin sensitivity. To this end, parallel fitness tests of over 60,000 unique insertion mutations were performed in strains with various alleles in genes encoding the drug targets. The spectra of mutations that altered drug sensitivity were found to be similar in the drug-sensitive and gyrA parC double-mutant backgrounds, having resistance alleles in both genes. In contrast, the introduction of a single gyrA resistance allele, resulting in preferential poisoning of topo IV by ciprofloxacin, led to extreme alterations in the insertion mutation fitness landscape. The distinguishing feature of preferential topo IV poisoning was enhanced induction of DNA synthesis in the region of two endogenous prophages, with DNA synthesis associated with excision and circularization of the phages. Induction of the selective DNA synthesis in the gyrA background was also linked to heightened prophage gene transcription and enhanced activation of the mutagenic SOS response relative to that observed in either the wild-type (WT) or gyrA parC double mutant. Therefore, the accumulation of mutations that result in the stepwise evolution of high ciprofloxacin resistance is tightly connected to modulation of the SOS response and endogenous prophage DNA synthesis.IMPORTANCE Fluoroquinolones have been extremely successful antibiotics due to their ability to target multiple bacterial enzymes critical to DNA replication, the topoisomerases DNA gyrase and topo IV. Unfortunately, mutations lowering drug affinity for both enzymes are now widespread, rendering these drugs ineffective for many pathogens. To undermine this form of resistance, we examined how bacteria with target alterations differentially cope with fluoroquinolone exposures. We studied this problem in the nosocomial pathogen A. baumannii, which causes drug-resistant life-threatening infections. Employing genome-wide approaches, we uncovered numerous pathways that could be exploited to raise fluoroquinolone sensitivity independently of target alteration. Remarkably, fluoroquinolone targeting of topo IV in specific mutants caused dramatic hyperinduction of prophage replication and enhanced the mutagenic DNA damage response, but these responses were muted in strains with DNA gyrase as the primary target. This work demonstrates that resistance evolution via target modification can profoundly modulate the antibiotic stress response, revealing potential resistance-associated liabilities.