Bactericidal activity of esculetin is associated with impaired cell wall synthesis by targeting glutamate racemase of Neisseria gonorrhoeae.

Neisseria gonorrhoeae (NG), the causative organism of gonorrhea, has been classified by the World Health Organization as 'Priority' two organism owing to its increased resistance to antibiotics and even failure of recommended dual therapy with ceftriaxone and azithromycin. As a result, the general and reproductive health of infected individuals is severely compromised. The imminent public health catastrophe of antimicrobial-resistant gonococci cannot be understated, as t he of severe complications and sequelae of infection are not only increasing but their treatment has also become more expensive. Tenacious attempts are underway to discover novel drug targets as well as new drugs to fight against NG. Therefore, a considerable number of phytochemicals have been tested for their remedial intercession via targeting bacterial proteins. The MurI gene encodes for an enzyme called glutamate racemase (MurI) that is primarily involved in peptidoglycan (PG) biosynthesis and is specific to the bacterial kingdom and hence can be exploited as a potential drug target for the treatment of bacterial diseases. Accordingly, diverse families of phytochemicals were screened in silico for their binding affinity with N. Gonorrhoeae MurI (NG-MurI) protein. Esculetin, one of the shortlisted compounds, was evaluated for its functional, structural, and anti-bacterial activity. Treatment with esculetin resulted in growth inhibition, cell wall damage, and altered permeability as revealed by fluorescence and electron microscopy. Furthermore, esculetin inhibited the racemization activity of recombinant, purified NG-MurI protein, one of the enzymes required for peptidoglycan biosynthesis. Our results suggest that esculetin could be further explored as a lead compound for developing new drug molecules against multidrug-resistant strains.

Ethambutol targets the glutamate racemase of Mycobacterium tuberculosis-an enzyme involved in peptidoglycan biosynthesis.

Increasing drug resistance in pathogens including Mycobacterium tuberculosis (MTB) has been ascribed to mutations in the known target genes. However, many of these drugs have multiple targets; some of which have not been identified so far. Understanding the mechanism of action of these drugs holds a great promise in better management of disease especially by drug-resistant strains. In this study, we report glutamate racemase (MurI), a crucial enzyme of phase I peptidoglycan (PG) biosynthesis pathway of MTB, as an additional target of ethambutol (EMB). The effect on EMB on the MurI protein at structural and functional level was studied using different spectroscopic, biochemical, and insilico approaches. Spectroscopic analysis revealed that EMB-modified protein undergoes conformational alterations. Furthermore, in vitro racemization studies of the MurI protein suggest that EMB decreases its functional activity. Docking studies revealed that EMB interacts with most of the active residues at the binding site and blocks the binding pocket. Overall, data suggests that EMB, a primary drug used for the treatment of tuberculosis (TB), acts as a competitive inhibitor of substrate for binding to mycobacterial MurI protein. The study also points out to our lacunae in understanding the site and mechanism of action of existing drugs. Furthermore, glutamate racemase is a conserved protein of the bacterial kingdom; therefore, ethambutol could be a promising candidate as a broad-spectrum antibiotic for many other bacterial diseases.

Serum Oxytocin Concentration in Patients Receiving Electroconvulsive Therapy: An Exploratory Study and Review of Literature.

BACKGROUND: Neuroendocrine biomarkers have long been studied in the context of electroconvulsive therapy (ECT). We prospectively assessed serum oxytocin change and moderators thereof in an exploratory study of patients receiving ECT. METHODS: Serum oxytocin concentrations were assessed immediately before and 1 to 3 minutes after the first ECT in 33 patients with schizophrenia (n = 14), other nonaffective psychosis (n = 6), mania (n = 10), and depression (n = 3) who received 6 to 7 bitemporal, brief-pulse ECTs. Change in serum oxytocin was assessed in the sample as a whole, and as a function of age, sex, diagnosis, and treatment response. The primary outcome was change in serum oxytocin in the overall sample. RESULTS: There was much variation across patients; oxytocin concentrations increased marginally by a mean (standard deviation) (M [SD]) of 6.4 (82.7) pg/mL (P = 0.43). The M (SD) change was -8.2 (85.0) pg/mL in patients with schizophrenia and other nonaffective psychoses (P = 0.84). There was no significant correlation between change in Brief Psychiatric Rating Scale scores and change in oxytocin concentrations in patients with schizophrenia, other nonaffective psychoses, and mania (ρ = 0.10, P = 0.61). Serum oxytocin rose in men, after ECT, and fell in women (P = 0.01). CONCLUSIONS: Change in serum oxytocin immediately after the first ECT in a course may not be a useful biomarker of ECT action. This is the first report on the subject in a sample comprising mostly patients with nonaffective psychosis and mania rather than depression. We discuss our findings in the light of previous research and offer general conclusions about the field.

Screening of natural compounds that targets glutamate racemase of Mycobacterium tuberculosis reveals the anti-tubercular potential of flavonoids.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (MTB), a highly infectious disease accounting for nearly 1.5 million deaths every year and has been a major global concern. Moreover, resistance to anti-TB drugs is an arduous obstacle to effective prevention, TB care and management. Therefore, incessant attempts are being made to identify novel drug targets and newer anti-tubercular drugs to fight with this deadly pathogen. Increasing resistance, adverse effects and costly treatment by conventional therapeutic agents have been inclining the researchers to search for an alternative source of medicine. In this regard natural compounds have been exploited extensively for their therapeutic interventions targeting cellular machinery of MTB. Glutamate racemase (MurI) is an enzyme involved in peptidoglycan (PG) biosynthesis and has become an attractive target due to its moonlighting property. We screened various classes of natural compounds using computational approach for their binding to MTB-MurI. Shortlisted best docked compounds were evaluated for their functional, structural and anti-mycobacterial activity. The results showed that two flavonoids (naringenin and quercetin) exhibited best binding affinity with MTB-MurI and inhibited the racemization activity with induced structural perturbation. In addition, fluorescence and electron microscopy were employed to confirm the membrane and cell wall damages in mycobacterial cells on exposure to flavonoids. Together, these observations could provide impetus for further research in better understanding of anti-tubercular mechanisms of flavonoids and establishing them as lead molecules for TB treatment.

Platelet Serotonin Level and Impulsivity in Human Self-destructive Behavior: A Biological and Psychological Study.

CONTEXT: Suicide is a disease and a global public health problem. Suicidology has come to become a topic of study for intervention and research. The serotonin (5-hydroxytryptamine [5HT]) system has remained a prime area of investigation. The neurons and platelets display structural and functional similarities. Ninety-nine percent of 5HT is contained in platelets, which shares similar 5HT uptake and release mechanisms with 5HT neurons. AIMS: This study aims to study human self-destructive behavior (HSDB). OBJECTIVES: Exploring the biological (serotonin levels in platelets) and psychological aspects (impulsivity) of attempted suicide or HSDB. SETTINGS AND DESIGN: Thirty-one patients, above the age of 18 years, with a recent history of HSDB, were studied and given an International Classification of Diseases-10 diagnosis, after a detailed interview. SUBJECTS AND METHODS: For the platelet 5HT estimation, blood samples were collected, and enzyme immunometric assay carried out. Detailed assessment of the impulsivity was done by the 25-item structured diagnostic interview for borderlines by Zanarini et al. STATISTICAL ANALYSIS USED: We obtained both categorical and continuous data. Chi-square test, Fisher's test, Student's t-test, and Pearson's product moment correlation were used. RESULTS: Female subjects outnumbered males by 2:1. Major depression, adjustment disorder, personality disorder were predominant diagnoses. The mean platelet serotonin concentration for males = 57.3 ng/ml, that of females = 56.05 ng/ml (P > 0.05). Platelet 5HT levels were found to be negatively correlated with impulsivity scores (P < 0.05). CONCLUSIONS: Platelet serotonin levels in our study sample were quite low when compared with those reported in published literature. Low serotonin levels were inversely related to impulsivity, but only in males.

Genital Self-mutilation in a Case of First Episode Psychosis.

Genital self-mutilation (GSM) is a much rare finding and more commonly associated with psychosis when it comes to comparison with self-mutilation as a whole. There have been anecdotal case reports of GSM in psychotic disorders with most of them being in long standing psychoses. We describe herein a case of GSM during the first episode of psychosis where multiple phenomenological variables were seen responsible for the act.

Idiopathic REM Sleep Behavior Disorder: A Report on Two Cases with Contrasting Features.

REM sleep behavior disorder (RBD) is a rare parasomnia in which persons exhibit uncharacteristic violent behavior, while dreaming. Secondary RBD occurs due to some neurological conditions, psychoactive substance or psychotropic drug use. There are no case reports on idiopathic RBD in India. We report here two cases to underscore the importance of identifying the disease as behavior associated with RBD may be quite serious in nature and might lead to catastrophic consequences.

Neuropsychiatric manifestations of Fahr's disease pathogenesis and potential for treatment.

Fahr's disease (FD) is a rare neuropsychiatric disease consisting of bilateral basal ganglia calcification with neurological, cognitive, and psychiatric manifestations. We report here a sporadic case of FDs with its neuropsychology.