Cyclic AMP binding to a universal stress protein in Mycobacterium tuberculosis is essential for viability.

Mycobacterial genomes encode multiple adenylyl cyclases and cAMP effector proteins, underscoring the diverse ways these bacteria utilize cAMP. We identified universal stress proteins (USP), Rv1636, and MSMEG_3811 in M. tuberculosis and M. smegmatis, respectively, as abundantly expressed, novel cAMP-binding proteins. Rv1636 is secreted via the SecA2 secretion system in M. tuberculosis but is not directly responsible for the efflux of cAMP from the cell. In slow-growing mycobacteria, intrabacterial concentrations of Rv1636 were equivalent to the concentrations of cAMP present in the cell. In contrast, levels of intrabacterial MSMEG_3811 in M. smegmatis were lower than that of cAMP and therefore, overexpression of Rv1636 increased levels of 'bound' cAMP. While msmeg_3811 could be readily deleted from the genome of M. smegmatis, we find that the rv1636 gene is essential for the viability of M. tuberculosis and is dependent on the cAMP-binding ability of Rv1636. Therefore, Rv1636 may function to regulate cAMP signaling by direct sequestration of the second messenger. This is the first evidence of a 'sponge' for any second messenger in bacterial signaling that would allow mycobacterial cells to regulate the available intrabacterial 'free' pool of cAMP.

A follow-up study of anxiety and depressive symptoms in irritable bowel syndrome.

Background: Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder and is closely linked to stress. Psychiatric morbidities such as anxiety and depression are common in IBS. Long-term follow-up studies on anxiety and depressive symptoms in IBS and the impact of treatment are lacking in the Indian scenario. Aims: This study aimed to assess the various subtypes of IBS according to the Rome IV criteria, assess anxiety and depressive symptoms in patients with IBS at baseline and also at various phases of follow-up over one year, and see the impact of the treatment of both IBS and associated anxiety and depressive symptoms if present, in the severity of IBS and other psychiatric symptoms. Materials and Methods: Patients with IBS, aged between 18 and 65 years, were enrolled for the study. Subtypes and severity of IBS were assessed. Anxiety and depressive symptoms were assessed by the Hamilton Rating Scale for Anxiety (HAM-A) and the Hamilton Rating Scale for Depression (HAM-D), respectively. The patients were treated with conventional treatment of IBS with concomitant treatment of anxiety and depressive symptoms and were followed up for 1 year. Results: Thirty-seven patients completed a 1-year follow-up. The mean age was 38.4 ± 11.6 years. The majority were males (81%), and IBS-D (84%) was the most common subtype. Stressful life events (67.6%) and chronic stressors (64.9%) were present in the majority of the patients. The patients had moderate-to-severe anxiety at baseline (HAM-A score 27.8 ± 6.4) and moderate-to-severe depression at baseline (HAM-D score 19.7 ± 6.6). The improvement over 1 year was statistically significant (P = 0.000, two-tailed). A positive correlation between the severity score of IBS and HAM-D (r = 0.604) and HAM-A (r = 0.536) scores was present. Conclusion: There is a high prevalence of anxiety and depression in patients with IBS. With adequate treatment of both IBS and concomitant anxiety-depressive symptoms, there is a significant decrease in the severity of IBS, anxiety, and depression.

Low genetic diversity of Treponema pallidum ssp. pertenue (TPE) isolated from patients' ulcers in Namatanai District of Papua New Guinea: Local human population is infected by three TPE genotypes.

Yaws is an endemic disease caused by Treponema pallidum subsp. pertenue (TPE) that primarily affects children in rural regions of the tropics. The endemic character of yaws infections and the expected exclusive reservoir of TPE in humans opened a new opportunity to start a yaws eradication campaign. We have developed a multi-locus sequence typing (MLST) scheme for TPE isolates combining the previously published (TP0548, TP0488) and new (TP0858) chromosomal loci, and we compared this typing scheme to the two previously published MLST schemes. We applied this scheme to TPE-containing clinical isolates obtained during a mass drug administration study performed in the Namatanai District of Papua New Guinea between June 2018 and December 2019. Of 1081 samples collected, 302 (28.5%) tested positive for TPE DNA, from which 255 (84.4%) were fully typed. The TPE PCR-positivity in swab samples was higher in younger patients, patients with single ulcers, first ulcer episodes, and with ulcer duration less than six months. Non-treponemal serological test positivity correlated better with PCR positivity compared to treponema-specific serological tests. The MLST revealed a low level of genetic diversity among infecting TPE isolates, represented by just three distinct genotypes (JE11, SE22, and TE13). Two previously used typing schemes revealed similar typing resolutions. Two new alleles (one in TP0858 and one in TP0136) were shown to arise by intragenomic recombination/deletion events. Compared to samples genotyped as JE11, the minor genotypes (TE13 and SE22) were more frequently detected in samples from patients with two or more ulcers and patients with higher values of specific TP serological tests. Moreover, the A2058G mutation in the 23S rRNA genes of three JE11 isolates was found, resulting in azithromycin resistance.

Brain MRI changes in degenerative cervical myelopathy: a systematic review.

BACKGROUND: Degenerative cervical myelopathy (DCM) is the most common cause of adult spinal cord dysfunction globally. Associated neurological symptoms and signs have historically been explained by pathobiology within the cervical spine. However, recent advances in imaging have shed light on numerous brain changes in patients with DCM, and it is hypothesised that these changes contribute to DCM pathogenesis. The aetiology, significance, and distribution of these supraspinal changes is currently unknown. The objective was therefore to synthesise all current evidence on brain changes in DCM. METHODS: A systematic review was performed. Cross-sectional and longitudinal studies with magnetic resonance imaging on a cohort of patients with DCM were eligible. PRISMA guidelines were followed. MEDLINE and Embase were searched to 28th August 2023. Duplicate title/abstract screening, data extraction and risk of bias assessments were conducted. A qualitative synthesis of the literature is presented as per the Synthesis Without Meta-Analysis (SWiM) reporting guideline. The review was registered with PROSPERO (ID: CRD42022298538). FINDINGS: Of the 2014 studies that were screened, 47 studies were identified that used MRI to investigate brain changes in DCM. In total, 1500 patients with DCM were included in the synthesis, with a mean age of 53 years. Brain alterations on MRI were associated with DCM both before and after surgery, particularly within the sensorimotor network, visual network, default mode network, thalamus and cerebellum. Associations were commonly reported between brain MRI alterations and clinical measures, particularly the Japanese orthopaedic association (JOA) score. Risk of bias of included studies was low to moderate. INTERPRETATION: The rapidly expanding literature provides mounting evidence for brain changes in DCM. We have identified key structures and pathways that are altered, although there remains uncertainty regarding the directionality and clinical significance of these changes. Future studies with greater sample sizes, more detailed phenotyping and longer follow-up are now needed. FUNDING: ODM is supported by an Academic Clinical Fellowship at the University of Cambridge. BMD is supported by an NIHR Clinical Doctoral Fellowship at the University of Cambridge (NIHR300696). VFJN is supported by an NIHR Rosetrees Trust Advanced Fellowship (NIHR302544). This project was supported by an award from the Rosetrees Foundation with the Storygate Trust (A2844).

Synthetically Tunable Suprahybrid Nanoparticle Platform for the Efficacious Delivery of Therapeutics.

The discovery of lipid-hybrid nanosystems has offered potential solutions to various drug delivery and theranostic challenges. However, in many instances, the commonly used lipids and other components in these systems often pose challenges related to their solubility, physicochemical properties, immune compatibility, and limited synthetic tunability. In this work, we introduce a synthetically tunable supramolecular scaffold with amphiphilic characteristics based on the calix[4]arene macrocyclic system. We designed and synthesized two novel calix[4]arene-polyethylene glycol (PEG) conjugates, termed Cal-P1 and Cal-P2, and these were characterized utilizing a wide range of spectroscopic and analytical methods. The rational design of Cal-P1 and Cal-P2 demonstrates their utility in forming stable blended nanospheres with sustained drug release characteristics. The synergistic blending of PLGA and the calixarene scaffold (Cal-P1 and Cal-P2) in constructing long-lasting and controlled-release nanoparticles (NPs), which are optimized for encapsulating Nile Red dye, and their successful internalization and retention in HeLa cancer cells are demonstrated through in vitro assays. The potential of these NPs as sustained therapeutic carriers is investigated in vivo, showing improved retention compared to free dye with negligible toxicity. The successful design and construction of Cal-P1 and Cal-P2 nanosystems represent a new paradigm for addressing drug loading challenges, opening up opportunities for the development of highly efficient, synthetically tunable alternative adjuvants for drug encapsulation and delivery.

Influence of time to clozapine prescription on the clinical outcome.

BACKGROUND: This study investigates whether early clozapine use is associated with improved responses in different clinical domains, including positive and negative symptoms, functioning, and well-being. METHODS: Data from 254 clozapine-treated patients at Cambridgeshire and Peterborough NHS Foundation Trust (CPFT) were analysed. Among them, 231 (90.9 %) had a diagnosis of schizophrenia, 21 (8.3 %) schizoaffective disorder, and 2 (0.8 %) had other diagnoses. The International Classification of Diseases-Mortality and Morbidity Statistics criteria (ICD-10) were employed (World Health Organization, 1992). The cohort was assessed using the positive and negative syndrome scale (PANSS), the Brief Negative Symptom Scale (BNSS), Global Assessment of Functioning Scale (GAF), and the short version of Warwick-Edinburgh Mental Well-being Scale (SWEMWBS). Logistic regression models (for positive and negative symptom remission) and linear regression (for functioning and well-being) were utilized to assess the influence of time to clozapine initiation (TCI), age at the first episode of psychosis (AFE), duration of clozapine treatment (DCT), and gender. RESULTS: Early clozapine treatment (within the first three years after the first episode of psychosis) was associated with increased negative symptom remission (exp (B) = 0.38; p = 0.02) and higher functioning scores (ß = -0.12, p = 0.046). However, no effect of time to clozapine initiation was found on positive symptom remission rates or well-being scores. CONCLUSIONS: Initiating clozapine treatment within the first 3 years of the first episode of psychosis may lead to reduced severity of negative symptoms and improved functioning in clozapine-treated patients. The time to clozapine initiation did not influence its effect on positive symptom remission rates.

Is the type and/or co-existence of degenerative spinal pathology associated with the occurrence of degenerative cervical myelopathy? A single centre retrospective analysis of individuals with MRI defined cervical cord compression.

BACKGROUND: Degenerative cervical myelopathy (DCM) arises from spinal degenerative changes injuring the cervical spinal cord. Most cord compression is incidental, referred to as asymptomatic spinal cord compression (ASCC). How and why ASCC differs from DCM is poorly understood. In this paper, we study a local cohort to identify specific types and groups of degenerative pathology more likely associated with DCM than ASCC. METHODS: This study was a retrospective cohort analysis (IRB Approval ID: PRN10455). The frequency of degenerative findings between those with ASCC and DCM patients were compared using network analysis, hierarchical clustering, and comparison to existing literature to identify potential subgroups in a local cohort (N = 155) with MRI-defined cervical spinal cord compression. Quantitative measures of spinal cord compression (MSCC and MCC) were used to confirm their relevance. RESULTS: ELF (8.7 %, 95 % CI 3.8-13.6 % vs 35.7 %, 95 % CI 27.4-44.0 %) Congenital Stenosis (3.9 %, 95 % CI 0.6-7.3 % vs 25.0 %, 95 % CI 17.5-32.5 %), and OPLL (0.0 %, 95 % CI 0.0-0.0 % vs 3.6 %, 95 % CI 0.3-6.8 %) were more likely in patients with DCM. Comparative network analysis indicated loss of lordosis was associated with ASCC, whilst ELF with DCM. Hierarchical Cluster Analysis indicated four sub-groups: multi-level disc disease with ELF, single-level disc disease without loss of lordosis and OPLL with DCM, and single-level disc disease with loss of lordosis with ASCC. Quantitative measures of cord compression were higher in groups associated with DCM, but similar in patients with single-level disc disease and loss of lordosis. CONCLUSIONS: This study identified four subgroups based on degenerative pathology requiring further investigation.

Supermicrosurgery: past, present and future.

Supermicrosurgery was popularised in 1997 and is defined as a technique of microvascular anastomosis for single nerve fascicles and vessels 0.3-0.8 mm in diameter. It requires the use of powerful microscopes, ultradelicate microsurgical instruments and specialist dyes. The development of supermicrosurgery has vastly improved the ability of microsurgeons to create true perforator flaps with minimal donor site morbidity for reconstructive surgery and improved the precision of additional microsurgical techniques. This review outlines the origins and history of supermicrosurgery, its current applications in reconstructive surgery (including fingertip reconstructions, true perforator flap surgery, nerve flaps and lymphoedema surgery), supermicrosurgery training and future directions for the field.

Application of the Clamshell Thoracotomy in an Infant with a Large Mediastinal Tumor.

Historically it was recommended for emergency thoracotomy in thoracic trauma as the last resort when there was cardiopulmonary arrest. Nowadays, the only indications are lung transplantation and huge mediastinal masses. We report the use of a clamshell thoracotomy in a 7-month-old boy with a large anterior mediastinal mass extending into the bilateral thoracic cavities.

Treatment of Umbilical Granuloma in Infants With Topical Application of Common Salt: A Scoping Review.

BACKGROUND: Common salt is a safe, effective and cheap home-made remedy for umbilical granuloma. The aim of this scoping review is to identify and summarize the available evidence and examine the research conducted on salt treatment for umbilical granuloma. METHODS: A literature search was performed in the second week of September, 2022 using Google scholar, PubMed, MEDLINE and EMBASE databases using the keywords 'umbilical granuloma' and 'salt treatment' to identify all English articles pertaining to salt treatment for umbilical granuloma. Tables were made to summarize the methodological characteristics, results and the dosage regimens of salt used by different authors. The Cochrane Collaboration's tool was used for assessing risk of bias in RCTs. The indexing statuses of the journals publishing these studies were also noted. The overall efficacy with the use of common salt was calculated by adding the success rates mentioned in each study. RESULTS: Twenty-four articles (2 systematic reviews, 6 Randomized Controlled Trials, 11 prospective cohort studies, 1 case control study, 3 retrospective case series and 1 case report) were included. An overall 93.91% success rate (1033/1100) was seen with common salt application, without any reports of complications/recurrences. CONCLUSION: Topical application of common salt for umbilical granulomas is simple, effective and inexpensive. This scoping review provides a broader outlook at the existing level of evidence and may help in planning interventional comparative studies, so that recommendations can be formulated. It also highlights a lack of properly designed randomized controlled trials on this topic. LEVEL OF EVIDENCE: I.

Role of Ultrasonography and Inflammatory Markers in Predicting Complicated Appendicitis.

Aim: The aim is to compare the diagnostic accuracy of laboratory investigations and ultrasonography (USG) in distinguishing complicated appendicitis (C-AA) from uncomplicated appendicitis (UC-AA). Materials and Methods: Forty-six children who underwent appendicectomy at our center between November 2018 and July 2020 were included. Based on intraoperative findings, they were divided into two groups - complicated (perforated, gangrenous, or associated with fecal peritonitis; n = 18) and UC-AA (n = 28). USG findings and inflammatory markers were compared in both groups at admission. Results: At admission, the mean values for total leukocyte count (TLC) (16090.56 vs. 11739.29 per mm3), high sensitivity C-reactive protein (hsCRP) (35.8 vs. 31.62 mg/L), and procalcitonin (PCT) (3.83 vs. 1.41 ng/mL) were significantly higher in C-AA. Visualization of a blind tubular aperistaltic structure was the only sonographic sign showing statistical significance - significantly lower in C-AA (50% vs. 90%). Independent predictors of C-AA were - duration of symptoms >48 h (odds ratio [OR] 6.3), free fluid/loculated collection in right iliac fossa (OR 3.75), TLC >11000/mm3 (OR 3.6), hsCRP >35 mg/L (OR 6.0), PCT >0.6 ng/mL (OR 4.02), and nonvisualization of appendix on USG (OR 8.33). Biochemical factors were sensitive (89%) and specific (55%) in differentiating C-AA from UC-AA but the addition of sonological parameters significantly improved the specificity of predicting complicated AA to 61% (P = 0.0036). Conclusion: Combining laboratory data with sonological findings significantly improves the predictive value for differentiating C-AA from UC-AA and can help decide operative approach and prognosticating.

A novel approach to single-cell analysis reveals intrinsic differences in immune marker expression in unstimulated BALB/c and C57BL/6 macrophages.

The origin of functional heterogeneity among macrophages, key innate immune system components, is still debated. While mouse strains differ in their immune responses, the range of gene expression variation among their pre-stimulation macrophages is unknown. With a novel approach to scRNA-seq analysis, we reveal the gene expression variation in unstimulated macrophage populations from BALB/c and C57BL/6 mice. We show that intrinsic strain-to-strain differences are detectable before stimulation and we place the unstimulated single cells within the gene expression landscape of stimulated macrophages. C57BL/6 mice show stronger evidence of macrophage polarization than BALB/c mice, which may contribute to their relative resistance to pathogens. Our computational methods can be generally adopted to uncover biological variation between cell populations.

Outcome of sequential dilatation in achalasia cardia patients: a prospective cohort study.

BACKGROUND: Sequential increment of balloon diameter for endoscopic pneumatic dilatation is a protocol that is used for symptomatic relief in achalasia cardia. However, most of the studies evaluating its effectiveness are retrospective in nature. This study intended to look into the efficacy of the above protocol in a prospective fashion. METHODS: Consecutive patients of achalasia cardia (n = 72) attending gastroenterology department were subjected to graded dilatation with 30, 35, and 40 mm pneumatic balloon and followed up (median 48 weeks; range: 4-96 weeks) with Eckardt score. Efficacy was assessed by proportion of patients achieving and maintaining clinical remission (Eckardt score ≤ 3) without requiring surgery during follow-up. RESULT: Overall 91% of patients (60 out of 66 with follow-up data) remained symptom free without requirement of surgery. Proportion of type 3 achalasia patients was significantly higher in the group requiring surgery compared to those who did not (p = 0.005). Threshold of 12 mm Hg in 4-week post-dilatation integrated relaxation pressure noted to predict future requirement of surgery in type 3 achalasia patients with sensitivity and specificity of 75% and 85%, respectively. Major adverse events requiring in-patient management were 2.9% with perforation noted in 1.9%. CONCLUSION: A sequential increment of balloon diameter for pneumatic dilatation in achalasia is an effective mode of therapy to achieve and maintain clinical remission in achalasia. The incidents of adverse events are low in this approach. Type 3 achalasia patients are more likely to require surgery despite sequential dilatation.

Laparoscopic versus open appendicectomy for complicated appendicitis in children: A systematic review and meta-analysis.

BACKGROUND: Laparoscopic appendectomy (LA) is the preferred approach in uncomplicated appendicitis. However, in patients with complicated appendicitis (CA), the best approach is still unclear though laparoscopy is being increasingly preferred over open appendicectomy (OA) nowadays. AIM: To comprehensively review the current literature and compare the associations of LA and OA concerning various postoperative outcomes in order to determine the best approach for children with CA. METHODS: The PRISMA guidelines were adhered to and an electronic database search was extensively performed. Data analysis, including subgroup analysis of randomized-control trials, was performed using RevMan 5.3. Methodological and statistical heterogeneity, as well as publication bias of the included studies, were assessed. RESULTS: Four randomized controlled trials (266 LA versus 354 OA) and thirty-six case-controlled trials (2580 LA versus 3043 OA) were included in the analysis. Compared to OA, LA has a shorter length of stay, a lower rate of surgical site infection as well as a significantly lower overall complication rate. The rates of intraabdominal abscess formation, post-operative fever, pneumonia and ileus are similar in the two groups. So are the rates of readmissions and reoperations. LA was also shown to have a shorter time taken to oral intake and a lesser requirement of analgesics as well as intravenous antibiotics. Operative time for OA was found to be significantly shorter than that for LA. CONCLUSION: This meta-analysis objectively demonstrates that laparoscopy has a better overall complication profile compared to OA and should be the procedure of choice in children with complicated appendicitis.

A universal stress protein in Mycobacterium smegmatis sequesters the cAMP-regulated lysine acyltransferase and is essential for biofilm formation.

Universal stress proteins (USPs) are present in many bacteria, and their expression is enhanced under various environmental stresses. We have previously identified a USP in Mycobacterium smegmatis that is a product of the msmeg_4207 gene and is a substrate for a cAMP-regulated protein lysine acyltransferase (KATms; MSMEG_5458). Here, we explored the role of this USP (USP4207) in M. smegmatis and found that its gene is present in an operon that also contains genes predicted to encode a putative tripartite tricarboxylate transporter (TTT). Transcription of the TTT-usp4207 operon was induced in the presence of citrate and tartrate, perhaps by the activity of a divergent histidine kinase-response regulator gene pair. A usp4207-deleted strain had rough colony morphology and reduced biofilm formation compared with the WT strain; however, both normal colony morphology and biofilm formation were restored in a Δusp4207Δkatms strain. We identified several proteins whose acetylation was lost in the Δkatms strain, and whose transcript levels increased in M. smegmatis biofilms along with that of USP4207, suggesting that USP4207 insulates KATms from its other substrates in the cell. We propose that USP4207 sequesters KATms from diverse substrates whose activities are down-regulated by acylation but are required for biofilm formation, thus providing a defined role for this USP in mycobacterial physiology and stress responses.

Acute upper gastrointestinal bleed: An audit of the causes and outcomes from a tertiary care center in eastern India.

BACKGROUND/PURPOSE OF THE STUDY: Acute upper gastrointestinal (UGI) bleed is a life-threatening emergency carrying risks of rebleed and mortality despite standard pharmacological and endoscopic management. We aimed to determine etiologies of acute UGI bleed in hospitalized patients and outcomes (rebleed rates, 5-day mortality, in-hospital mortality, 6-week mortality, need for surgery) and to determine predictors of rebleed and mortality. METHODS: Clinical and endoscopic findings were recorded in patients aged > 12 years who presented within 72 h of onset of UGI bleed. Outcomes were recorded during the hospital stay and 6 weeks after discharge. RESULTS: A total of 305 patients were included in this study, mean age being 44 ± 17 years. Most common etiology of UGI bleed was portal hypertension (62.3%) followed by peptic ulcer disease (PUD) (16.7%). Rebleed rate within 6 weeks was 37.4% (portal hypertension 47.9%, PUD 21.6%, malignancy 71.4%). Five-day mortality was 2.3% (malignancy 14.3%, portal hypertension 3.2%); the in-hospital mortality rate was 3.0% (malignancy 14.3%, portal hypertension 3.2%, PUD 0.0%) and 4.9% at 6 weeks (malignancy 28.6%, portal hypertension 5.8%, PUD 0.0%). Surgery was required in 4.59% patients. On multivariate analysis, post-endoscopy Rockall score was significantly predictive of rebleed in both portal hypertension- and PUD-related rebleed. No factors were found predictive of mortality in multivariate analysis. CONCLUSION: Portal hypertension remains the commonest cause of UGI bleed in India and carries a higher risk of rebleed and mortality as compared to PUD-related bleed. Post-endoscopy Rockall score is a useful tool for clinicians to assess risk of rebleed.

Probiotics L. acidophilus and B. clausii Modulate Gut Microbiota in Th1- and Th2-Biased Mice to Ameliorate Salmonella Typhimurium-Induced Diarrhea.

Gut microbiota play important role in maintaining health. Probiotics are believed to augment it further. We aimed at comparing effects of probiotics, Lactobacillus acidophilus (LA) and Bacillus clausii (BC) (a) on the gut microbiota abundance and diversity and (b) their contributions to control intestinal dysbiosis and inflammation in Th1- and Th2-biased mice following Salmonella infection. We report how could gut microbiota and the differential immune bias (Th1 or Th2) of the host regulate host responses when challenged with Salmonella typhimurium in the presence and absence of either of the probiotics. LA was found to be effective in ameliorating the microbial dysbiosis and inflammation caused by Salmonella infection, in Th1 (C57BL/6) and Th2 (BALB/c)-biased mouse. BC was able to ameliorate Salmonella-induced dysbiosis and inflammation in Th2 but not in Th1-biased mouse. These results may support probiotics LA as a treatment option in the case of Salmonella infection.

Immune activation efficacy of indolicidin is enhanced upon conjugation with carbon nanotubes and gold nanoparticles.

Antibiotic resistance is concern of today's world. Search for alternative molecules, for treatment and immune stimulation, remains at the forefront. One such group of biomolecules with promise, along the line of immune stimulation or therapy, is host defense peptide (HDP). These molecules, however, are required at a higher dose to be effective which leads to high cost. To alleviate such problems, an aid can be used to achieve similar efficacy but at a smaller effective dose of the immune stimulant. We hypothesised that by conjugating HDPs with carbon nanotubes and/or gold nanoparticles, it would be possible to stimulate a protective immune response in host system at a lower dosage of HDP. In this report, we characterized, using biophysical methodologies, conjugation of Indolicidin, as a representative of HDP. We further established efficacy of peptide-nanomaterial conjugates in activating innate immunity and protecting against pathogen infection in vitro at a significantly small dose.

A universal stress protein (USP) in mycobacteria binds cAMP.

Mycobacteria are endowed with rich and diverse machinery for the synthesis, utilization, and degradation of cAMP. The actions of cyclic nucleotides are generally mediated by binding of cAMP to conserved and well characterized cyclic nucleotide binding domains or structurally distinct cGMP-specific and -regulated cyclic nucleotide phosphodiesterase, adenylyl cyclase, and E. coli transcription factor FhlA (GAF) domain-containing proteins. Proteins with cyclic nucleotide binding and GAF domains can be identified in the genome of mycobacterial species, and some of them have been characterized. Here, we show that a significant fraction of intracellular cAMP is bound to protein in mycobacterial species, and by using affinity chromatography techniques, we identify specific universal stress proteins (USP) as abundantly expressed cAMP-binding proteins in slow growing as well as fast growing mycobacteria. We have characterized the biochemical and thermodynamic parameters for binding of cAMP, and we show that these USPs bind cAMP with a higher affinity than ATP, an established ligand for other USPs. We determined the structure of the USP MSMEG_3811 bound to cAMP, and we confirmed through structure-guided mutagenesis, the residues important for cAMP binding. This family of USPs is conserved in all mycobacteria, and we suggest that they serve as "sinks" for cAMP, making this second messenger available for downstream effectors as and when ATP levels are altered in the cell.