Anti-listerial peptides from a marine Bacillus velezensis FTL7: production optimization, characterizations and molecular docking studies.

Antimicrobial peptides (AMPs) with potent anti-listerial activity were characterized from a novel marine Bacillus velezensis FTL7. A Box-Behnken statistical experimental design was used to study the combined impact of culture conditions on the production of AMPs by B. velezensis FTL7. The conditions optimized by statistical experimental design were 34.5 °C incubation temperature, 23 h incubation time, and 7.6 initial pH of the medium. AMP purification was performed by ammonium sulphate fractionation and butanol extraction followed by reversed-phase C18 solid-phase extraction. Tricine-SDS-PAGE analysis revealed a peptide with a molecular mass of ~ 6.5 kDa in an active AMPs fraction, whereas the mass spectrometry (MS) analysis showed the presence of AMPs in the mass range of 1-1.6 kDa, along with a 6.5 kDa peptide. Both MS and MS/MS analysis confirmed the AMPs as lipopeptides including surfactin, fengycins and iturin A and a circular bacteriocin amylocyclicin. The minimum inhibitory concentration of these AMPs against L. monocytogenes Scott A was 2.5 µg/mL. Further, the in-silico docking studies showed that the AMPs from B. velezensis FTL7 have high binding energy and stable binding patterns towards L. monocytogenes target proteins. Thus, this new combination of AMPs can serve as an effective food bio-preservative. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03944-5.

Nrf2-regulated antioxidant response ameliorating ionizing radiation-induced damages explored through in vitro and molecular dynamics simulations.

This study aims to investigate the mechanism of natural antioxidant ferulic acid (FA) in reducing oxidative stress followed by its inhibitory effect on the Keap1-Nrf2 complex. FA was treated ex vivo with human blood for 30 min at 37 °C ± 1 °C and exposed to 1.5 Gy of γ- rays of 60Co (0.789 Gy/min) and allowed for repair for an hour at 37 °C ± 1 °C. FA's free radical scavenging capacity was measured using 2,7-dichlorofluorescein diacetate assay and cytogenetic assays. Further, a possible mechanism of protein-ligand interaction between FA and Keap1-Nrf2 pathway protein as a cellular drug target was studied using docking and molecular dynamics simulation. The 1.5 Gy of γ- rays exposed to pre-treated blood with FA showed a significant (p < 0.05) reduction in reactive oxygen species and DNA damage compared to the normal control blood group sample. The ligand-protein transient binding interaction in molecular dynamic simulation over a period of 100 ns was consistent and stable emphasizing complementary charge between the protein and ligand, speculating higher hydrophobic amino acid residues in the Keap1 active pocket. This might sway the Keap1 from interaction with Nrf2, and could lead to nuclear translocation of Nrf2 during radiation-induced oxidative stress. The present study emphasizes the radioprotective effect of FA against 1.5 Gy of γ- rays exposed to human blood and the application of in silico approaches helpful for the possible protective effect of FA.Communicated by Ramaswamy H. Sarma.

Structure-based screening of natural product libraries in search of potential antiviral drug-leads as first-line treatment to COVID-19 infection.

The study focuses on identifying and screening natural products (NPs) based on their structural similarities with chemical drugs followed by their possible use in first-line treatment to COVID-19 infection. In the present study, the in-house natural product libraries, consisting of 26,311 structures, were screened against potential targets of SARS-CoV-2 based on their structural similarities with the prescribed chemical drugs. The comparison was based on molecular properties, 2 and 3-dimensional structural similarities, activity cliffs, and core fragments of NPs with chemical drugs. The screened NPs were evaluated for their therapeutic effects based on their predicted in-silico pharmacokinetic and pharmacodynamics properties, binding interactions with the appropriate targets, and structural stability of the bound complex using molecular dynamics simulations. The study yielded NPs with significant structural similarities to synthetic drugs currently used to treat COVID-19 infections. The study proposes the probable biological action of the selected NPs as Anti-retroviral protease inhibitors, RNA-dependent RNA polymerase inhibitors, and viral entry inhibitors.

Receptor based virtual screening of potential novel inhibitors of tigar [TP53 (tumour protein 53)-induced glycolysis and apoptosis regulator.

TP53 (tumor protein 53)-induced glycolysis and apoptosis regulator (TIGAR) belongs to the phosphatases family of proteins that modulates the level of reactive oxygen species in tumor cells. This protein plays a vital role as a negative regulator of glycolysis, thus lowering ROS levels in the cells, which helps the cancerous cells to resist programmed cell death. Besides, TIGAR also mediates the DNA damage repair in cancer cells by increasing tumor cell survival. In the current study, we have screened natural products that compete with the substrate to bind to the active site of TIGAR. Extra precision and MMGBSA scoring function were used to screen the lead molecules. Five compounds were considered as lead molecules with 2-(2-(3,4-dihydroxy phenyl)-3,5-dihydroxy-8-(4-hydroxyphenyl)-4-oxo-4H-furo[2,3-h]chromen-9-yl) acetic acid(DDFA) as a top lead with a docking score of -9.428, and -53.16 MMGBSA, bind to the positively charged amino acids present in the active site. Further, the molecular dynamics simulation studies indicated the structural stability attained by TIGAR protein upon the binding of DDFA, suggesting it to be a potent inhibitor of TIGAR, and could be employed as an anticancer drug during combinational therapy.

Evolutionary selectivity of amino acid is inspired from the enhanced structural stability and flexibility of the folded protein.

AIM: The present study attempts to decipher the site-specific amino acid alterations at certain positions experiencing preferential selectivity and their effect on proteins' stability and flexibility. The study examines the selection preferences by considering pair-wise non-bonded interaction energies of adjacent and interacting amino acids present at the interacting site, along with their evolutionary history. MATERIALS AND METHODS: For the study, variations in the interacting residues of spike protein (S-Protein) receptor-binding domain (RBD) of different coronaviruses were examined. The MD simulation trajectory analysis revealed that, though all the variants studied were structurally stable at their native and bound confirmations, the RBD of 2019-nCoV/SARS-CoV-2 was found to be more flexible and more dynamic. Furthermore, a noticeable change observed in the non-bonded interaction energies of the amino acids interacting with the receptor corroborated their selection at respective positions. KEY FINDINGS: The conformational changes exerted by the altered amino acids could be the reason for a broader range of interacting receptors among the selected proteins. SIGNIFICANCE: The results envisage a strong indication that the residue selection at certain positions is governed by a well-orchestrated feedback mechanism, which follows increased stability and flexibility in the folded structure compared to its evolutionary predecessor.

Factors Influencing Survival of Children with Atypical Teratoid/Rhabdoid Tumors: A Single-Institute Experience in a Developing Country.

BACKGROUND: We evaluated the factors influencing overall survival (OS) and event-free survival (EFS) in children with atypical teratoid/rhabdoid tumors (ATRTs). METHODS: We performed a retrospective study of children aged <16 years and tumor histological diagnosis of ATRT. Univariate and multivariate analyses were performed to determine the effect of individual and interdependent variables and survival. RESULTS: A total of 34 children had undergone surgery, with a male/female ratio of 1.8:1. On univariate analysis, the factors with statistically significant influence on OS and EFS were the extent of resection (P = 0.012 and P = 0.015, respectively), adjuvant therapy (P ≤ 0.001 and P = 0.001, respectively), and rhabdoid cell percentage (P = 0.004 and P = 0.005, respectively). On survival analysis, the median OS and EFS were better for those who had completed adjuvant therapy versus those who had not received adjuvant therapy (OS, 22.7 months vs. 3.5 months; EFS, 10.9 months vs. 3.5 months), those who had undergone gross total resection versus those who had undergone partial decompression (OS, 10.9 months vs. 2 months; EFS, 8.9 months vs. 2.5 months), and those with <50% rhabdoid cells in the biopsy specimen versus those with >50% rhabdoid cells (OS, 10.9 months vs. 3.7 months; EFS, 8.9 months vs. 3.5 months). On multivariate analysis, only the extent of resection and adjuvant therapy status had a significant influence on OS and EFS. CONCLUSION: Achieving gross total resection should be the aim of surgery, depending on the tumor location, and these children should undergo upfront adjuvant treatment.

Lumbar Intramedullary Epidermoid Following Repair of Sacral Myelomeningocele and Tethered Cord: A Case Report With a Review of the Relevant Literature and Operative Nuances.

Epidermoid cysts of the spine are rare tumors. While the majority of them occur spontaneously, in very few cases, they can occur following previous surgery for spinal dysraphism. Such tumors tend to occur at the site of previous surgery. The occurrence of an epidermoid cyst at a level higher than the previous surgical site is a rare entity. We present a rare case of a lumbar intramedullary and extramedullary epidermoid occurring at a level higher than the previous surgical site, along with a discussion of the causes of such an occurrence and operative nuances regarding the management of an intramedullary epidermoid in a pediatric patient.

Augmentation of pyrethrins content in callus of Chrysanthemum cinerariaefolium and establishing its insecticidal activity by molecular docking of NavMS Sodium Channel Pore receptor.

Pyrethrins are effective food-grade bio-pesticides obtained from the flowers of Chrysanthemum cinerariaefolium and this crop cannot be cultivated widely in India due to its specific agro-climatic requirement. Hence pyrethrins are mostly imported from Kenya. Therefore, the present study aims to develop a process for augmentation of pyrethrin contents in C. cinerariaefolium callus and establish the correlation between early knockdown effects through docking on grain storage insect. In vitro seedlings were used as explants to induce callus on MS medium with different concentrations of auxins and cytokinins. Pyrethrin extracted from the callus was estimated by RP-HPLC. In callus, total pyrethrin was found to be 17.5 µg/g, which is higher than that found in natural flowers of certain Pyrethrum cultivars. The concentrations of cinerin II, pyrethrin II and jasmoline II were quite high in callus grown on solid medium. Bio-efficacy of pyrethrum extracts of flower and callus on insect Tribolium sp., showed higher repellency and early knock-down effect when compared with pure compound pestanal. Further, the rapid knockdown effect of all pyrethrins components was established by molecular docking studies targeting NavMS Sodium Channel Pore receptor docking followed by multiple ligands simultaneous docking, performed to investigate the concurrent binding of different combinations of pyrethrin. Among the six pyrethrin components, the pyrethrin I and II were found to be a more efficient, binding more firmly to the target, exhibiting higher possibilities of insecticidal effect by an early knockdown mechanism.

Management dilemmas in a rare case of pituitary apoplexy in the setting of dengue hemorrhagic fever.

BACKGROUND: Pituitary apoplexy occurs due to infarction or hemorrhage, within a pituitary adenoma or a nontumorous pituitary gland and can have catastrophic consequences. Dengue hemorrhagic fever (DHF) is a severe manifestation of the spectrum of dengue virus infection and is characterized by high-grade fever, thrombocytopenia, hemorrhagic tendencies, and increased vascular permeability. Cases of incidentalomas complicated by DHF and presenting with apoplexy are extremely rare. CASE DESCRIPTION: We describe the case of a 45-year-old gentleman who suffered an attack of pituitary apoplexy while being treated for DHF. The issues pertaining to the management of hydrocephalus, timing of surgical intervention, and treatment of electrolyte imbalances encountered in the dual setting of DHF and pituitary apoplexy are discussed with reference to the outcome in our case. CONCLUSION: Although patients suffering from DHF harbor multiple factors, which may be precipitants of pituitary apoplexy, the association between these two conditions is rare and only few case reports document their coexistence. We review the pertinent literature and discuss the management dilemmas faced by us while dealing with these dual pathological states.

Multiple ligand simultaneous docking (MLSD): A novel approach to study the effect of inhibitors on substrate binding to PPO.

Multiple ligand simultaneous docking, a computational approach is used to study the concurrent interactions between substrate and the macromolecule binding together in the presence of an inhibitor. The present investigation deals with the study of the effect of different inhibitors on binding of substrate to the protein Polyphenoloxidase (PPO). The protein was isolated from Mucuna pruriens and confirmed as tyrosinases involved in L-DOPA production. The activity was measured using different inhibitors at different concentrations taking catechol as substrate. A high-throughput binding study was conducted to compare the binding orientations of individual ligands and multiple ligands employing Autodock 4.2. The results of single substrate docking showed a better binding of urea with the binding energy of -3.48 kJ mol(-1) and inter molecular energy of -3.48 kJ mol(-1) while the results of MLSD revealed that ascorbic acid combined with the substrate showed better inhibition with a decreased binding energy of -2.37 kJ mol(-1).

Phosphatidylinositol 3-kinase and focal adhesion kinase are early signals in the growth factor-like responses to thrombospondin-1 seen in human vascular smooth muscle.

Thrombospondin-1 (TSP-1) is a matricellular protein that is expressed in negligible amounts in normal blood vessels but is markedly upregulated in vascular injury. Although TSP-1 can act as a pleiotropic regulator for human vascular smooth muscle cells (HVSMCs), the intracellular signaling pathways stimulated by this protein remain obscure. In cultured HVSMCs derived from saphenous vein, TSP-1 induces tyrosine phosphorylation of a number of cellular proteins, with a complex temporal pattern of activation. Immunoprecipitation techniques have identified the early tyrosine-phosphorylated signals as being the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI 3-K) and focal adhesion kinase (FAK). Tyrosine phosphorylation of the p85 subunit of PI 3-K showed a biphasic response to TSP-1 stimulation, which corresponded to a biphasic activation of the lipid kinase. Treatment with both wortmannin and LY294002 inhibited PI 3-K activity of HVSMCs but did not affect tyrosine phosphorylation of the p85 regulatory subunit. TSP-1-stimulated FAK phosphorylation, however, was substantially reduced by these inhibitors, as was the TSP-1-induced chemotaxis of these cells. These results suggest that activation of PI 3-K is an early signal induced by TSP-1 and is critical for chemotaxis. Activation of this kinase precedes and may occur upstream from FAK phosphorylation, although the nature of the interaction between these 2 enzymes remains obscure.

Comparison of regional brain metabolism in bulimia nervosa and affective disorder assessed with positron emission tomography.

Women with bulimia often present with symptoms of depression in addition to bingeing and purging behavior. Brain metabolism in eight women with bulimia nervosa was compared to that in eight women with major affective disorder and eight normal women, using positron emission tomography and 18-fluoro-2-deoxyglucose. Normal women have higher right than left cortical metabolic rates and active basal ganglia. Bulimics lost the normal right activation in some areas, but maintained basal ganglia activity. Depressives retained right hemisphere activation, but had decreased metabolism in basal ganglia. This suggests that although women with bulimia frequently present with symptoms of depression, the pathophysiologic changes associated with bulimia differ from major effective disorder.