Investigating the pro-inflammatory differentiation of macrophages with bacterial ghosts in potential infection control.

In the complex realm of bacterial infections, particularly those caused by Staphylococcus aureus (S. aureus), macrophages play a pivotal role in orchestrating the immune response. During the initial stages of infection, the monocytes give rise to macrophages with a pro-inflammatory (M1 type) behaviour, engulfing and neutralizing the invading pathogens. However, under the sustained influence of S. aureus infection, monocytes can undergo a transition into an anti-inflammatory M2 state (pro-infection) rather than the M1 state (anti-infection), thereby compromising effective infection control. Therefore, it is necessary to develop a strategy that would preserve the pro-inflammatory functions of macrophages, in a safe and controlled manner. For this, we focused on harnessing the potential of S. aureus-derived ghost cells (GCs) which are non-live empty envelopes of bacterial cells, but with the antigenic determinants intact. Through a unique Lugol's-iodine treatment, we generated GCs and characterization of these GCs using gel electrophoresis, FTIR, flow cytometry, TEM, and SEM confirmed their structural integrity. Following this, we assessed the extend of cellular association of the GCs with RAW267.4 macrophages, and observed an immediate interaction between the two, as evident from the flowcytometry and microscopy studies. We then performed macrophage polarisation on a human monocyte-macrophage model cell line, THP-1. Our findings revealed that GCs effectively activated macrophages, and promoted a pro-inflammatory polarisation with the expression of M1 differentiation markers (CD86, TNFα, IL-1ß, IL-6, IL-12) evaluated through both qPCR and ELISA. Interestingly an intermediary expression of M2 markers viz., CD206 and IL-10 was also observed, but was overruled by the enhanced expression of M1 markers at a later time point. Overall, our study introduces a novel approach utilizing GCs to guide naïve macrophages towards M1 subtypes, thereby potentiating immune responses during microbial infections. This innovative strategy can modulate macrophage function, ultimately improving outcomes in S. aureus infections and beyond.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy.

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

A Porphyrin-based NIR Fluorescent Probe for Bi3+ and Potential Applications.

Herein, we have prepared a 5,10,15,20-Tetrakis(4-hydroxyphenyl) porphyrin (P) which acts as a probe for selective and sensitive detection of Bi3+ ions. Probe P was obtained by reacting pyrrole with 4-hydroxyl benzaldehyde and characterized by NMR, IR, and ESI-MS. All photo-physical studies of P were tested in DMSO:H2O (8:2, v/v) media by spectrophotometry and spectrofluorometry respectively. The selectivity of P was tested with different metal ions in solution as well as in the solid phase, only Bi3+ showed red fluorescence quenching while with other metal ions, no such effect was observed. The Job's plot unveiled the 1:1 stoichiometric binding ratio of the probe with Bi3+ and anticipated association constant of 3.4 ×105 M-1, whereas the Stern-Volmer quenching constant was noticed to be 5.6 ×105 M-1. Probe P could detect Bi3+ down to 27 nM by spectrofluorometric. The binding mechanism of P with Bi3+ was well supported with NMR, mass, and DFT studies. Further, the P was applied for the quantitative determination of Bi3+ in various water samples and the biocompatibility of P was examined using neuro 2A (N2a) cells. Overall, probe P proves promising for the detection of Bi3+ in the semi-aqueous phase and it is the first report as a colorimetric and fluorogenic probe.

Demonstrating the immunostimulatory and cytokine-augmentation effects of bacterial ghosts on natural killer cells and Caenorhabditis Elegans.

The potential of bacteria-based immunotherapy lies in its ability to inherently enhance immune responses. However, the "liveness" of bacteria poses risks of bacterial escape, nonspecific immuno-stimulation, and ethical concerns, limiting their acceptability in immunotherapy. In this scenario, nonliving empty bacterial-cell envelopes, named bacterial ghosts (BGs), have emerged as immuno-stimulants with the potential to side-step the limitations of live bacterial therapies. This study demonstrates the capability of BGs in modulating the functionality of NK-92 cells and Caenorhabditis elegans (C. elegans), as well as perform as cytokine-therapy adjuvants. BGs were obtained through a pH-driven culture method, and were validated for their structural and chemical integrity via electron microscopy and spectroscopy. In NK-92 cells, BGs have shown significant immuno-stimulation by boosting the gene-expression of perforin, granzyme-B, Fas-L, and interferon-gamma by factors of 3.5-, 1.5-, 12.5-, and 8.6-folds, respectively. Combined BG and IL-12 treatment yielded a notable 10.2-fold increase in interferon-gamma protein expression in 24 h. The BGs also significantly influenced the innate immune response in C. elegans through the upregulation of lysozyme genes viz., ilys-3 (8.8-fold) and lys-2 (3.1-fold). Our investigation into the impact of BGs on natural killer cells and C. elegans highlights its potential as a valid alternative approach for new-age immunotherapy and cytokine augmentation.

A Simple Live Cell Imaging "Turn-On" Fluorescence Probe for the Selective and Sensitive Detection of Aqueous Hg2+ Ions.

A simple, efficient, and reversible fluorescent sensor probe, PBA (2,6-dimethyl pyrone barbituric acid conjugate), comprised of a pro-aromatic donor conjugated with a barbituric acid, was developed for the detection of highly toxic mercuric ions. The probe showed high selectivity and "Turn-On" fluorescence response towards Hg2+ among various metal cations such as Na+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Ba2+, Hg2+, and Pb2+, in both homogeneous and microheterogeneous micelle medium sodium dodecyl sulphate (SDS). The binding stoichiometry, limit of detection (LOD), and binding constant for the PBA-Hg complex were determined. The mechanism of binding was ascertained using the N,N'-dimethylbarbituric acid conjugate of 2,6-dimethylpyran (PDMBA), where no binding interaction by deprotonation is possible. In the presence of cysteamine hydrochloride and trifluoroacetic acid (TFA), the complexation of Hg2+ with PBA was demonstrated to be reversible, indicating its potential for the development of reusable sensors. Moreover, the practical applicability of PBA in monitoring Hg2+ in living cells was also evaluated.

Whole genome sequence analysis enabled affirmation of the probiotic potential of marine sporulater Bacillus amyloliquefaciens BTSS3 isolated from Centroscyllium fabricii.

Probiotics are microorganisms when administered in adequate amounts, confer health benefits on the host. Many probiotics find application in various industries however, probiotic bacteria linked to marine environments are less explored.Although Bifidobacteria, Lactobacilli, and Streptococcus thermophilus are the most frequently used probiotics, Bacillus spp. have acquired much acceptance in human functional foods due to their increased tolerance and enduring competence in harsh environments like the gastrointestinal (GI) tract. In this study, the 4 Mbp genome sequence of Bacillus amyloliquefaciens strain BTSS3, a marine spore former isolated from deep-sea shark Centroscyllium fabricii, with antimicrobial and probiotic properties was sequenced, assembled, and annotated. Analysis revealed the presence of numerous genes presenting probiotic traits like production of vitamins, secondary metabolites, amino acids, secretory proteins, enzymes and other proteins that allow survival in GI tract as well as adhesion to intestinal mucosa. Adhesion by colonization in the gut was studied in vivo in zebrafish (Danio rerio) using FITC labelled B.amyloliquefaciens BTSS3. Preliminary study revealed the ability of the marine Bacillus to attach to the intestinal mucosa of the fish gut. The genomic data and the in vivo experiment affirms that this marine spore former is a promising probiotic candidate with potential biotechnological applications.

Appraisal of cytotoxicity and acrylamide mitigation potential of L-asparaginase SlpA from fish gut microbiome.

L-asparaginase catalyzes the hydrolysis of L-asparagine to L-aspartic acid and ammonia. It has application in the treatment of acute lymphoblastic leukemia in children, as well as in other malignancies, in addition to its role as a food processing aid for the mitigation of acrylamide formation in the baking industry. Its use in cancer chemotherapy is limited due to problems such as its intrinsic glutaminase activity and associated side effects, leading to an increased interest in the search for novel L-asparaginases without L-glutaminase activity. This study reports the cloning and expression of an L-asparaginase contig obtained from whole metagenome shotgun sequencing of Sardinella longiceps gut microbiota. Purified recombinant glutaminase-free L-asparaginase SlpA was a 74 kDa homodimer, with maximal activity at pH 8 and 30 °C. Km and Vmax of SlpA were determined to be 3.008 mM and 0.014 mM/min, respectively. SlpA displayed cytotoxic activity against K-562 (chronic myeloid leukemia) and MCF-7 (breast cancer) cell lines with IC50 values of 0.3443 and 2.692 U/mL, respectively. SlpA did not show any cytotoxic activity against normal lymphocytes and was proved to be hemocompatible. Pre-treatment of biscuit and bread dough with different concentrations of SlpA resulted in a clear, dose-dependent reduction of acrylamide formation during baking. KEY POINTS: • Cloned and expressed L-asparaginase (SlpA) from fish gut microbiota • Purified SlpA displayed good cytotoxicity against K-562 and MCF-7 cell lines • SlpA addition caused a significant reduction of acrylamide formation during baking.

Novel 3D porous aerogels engineered at nano scale from cellulose nano fibers and curcumin: An effective treatment for chronic wounds.

Traditional cotton gauze derived from cellulose has many limitations in the processes of wound healing. To overcome these hassles, we used cellulose nanofibers (CNF) incorporated with curcumin for the fabrication of wound healing 3D porous aerogel. Cellulose nanofibers synthesized from plant waste are promising sustainable nanomaterials due to their biocompatibility and biodegradability. Ionic cross linking with sodium alginate was performed to maintain the mechanical strength. SEM results revealed highly porous architecture that effectively promoted wound healing, as a result of macro- and micro-porous architecture and curcumin. In-vitro drug release studies showed a slow and steady release pattern. The 3D porous nano bio aerogel with curcumin significantly promoted the migration of fibroblast cells and had excellent antimicrobial activity against pathogenic microorganisms. In-vivo studies showed angiogenesis without rejection or inflammation of the scaffold. From the observations, we can conclude that this novel 3D porous aerogel can be used to treat chronic wounds.

Indian oil sardine (Sardinella longiceps) gut derived Bacillus safensis SDG14 with enhanced probiotic competence for food and feed applications.

Probiotics are considered as functional food as they provide health benefits along with traditional nutrition. Spore forming probiotic Bacillus are of commercial interest than Lactic Acid Bacillus due to their relatively lower cost of production and higher survivability. In the present study we identified the bacterial strain SDG14 isolated from Indian oil Sardine by Average Nucleotide Identity of whole genome sequence. The whole genome of SDG14 was also explored for pathogenicity, the presence of genes responsible for probiotic traits such as spore formation, resistance to host gastrointestinal tract conditions, adhesion to intestinal mucosa, interference in pathogen survival, expression of bacteriocins, oxidative and other stress responses, absorption of nutrition, production of essential amino acids and vitamins. Wet lab experiments for probiotic characterization were also conducted. The organism was confirmed to be Bacillus safensis SDG14. The possible pathogenicity of the organism was also ruled out by in silico analysis. Bacillus safensis SDG14 was able to survive at pH 3 and bile salt concentration of 0.5% (w/v). The adhesion index of Bacillus safensis SDG14 on HEp-2 was 36.82 ± 5.93 and 45.54 ± 9.55 respectively after 60 and 90 min of incubation and self aggregation percentage was 18.4 ± 0.48% after 3 h. Bacillus safensis SDG14 produced bacteriocin and co-aggregated with E. coli, Salmonella Typhimurium and Pseudomonas aeruginosa. The genomic data supported the findings of wet lab study and vice versa. Bacillus safensis SDG14 was proved to be a non-pathogenic, spore forming, pH and bile salt resistant, bacteriocin, amino acid and vitamin producing probiotic with proposed food and feed applications.

Metagenomic landscape of taxonomy, metabolic potential and resistome of Sardinella longiceps gut microbiome.

Fish gut microbiota, encompassing a colossal reserve of microbes represents a dynamic ecosystem, influenced by a myriad of environmental and host factors. The current study presents a comprehensive insight into Sardinella longiceps gut microbiome using whole metagenome shotgun sequencing. Taxonomic profiling identified the predominance of phylum Proteobacteria, comprising of Photobacterium, Vibrio and Shewanella sp. Functional annotation revealed the dominance of Clustering based subsystems, Carbohydrate, and Amino acids and derivatives. Analysis of Virulence, disease and defense subsystem identified genes conferring resistance to antibiotics and toxic compounds, like multidrug resistance efflux pumps and resistance genes for fluoroquinolones and heavy metals like cobalt, zinc, cadmium and copper. The presence of overlapping genetic mechanisms of resistance to antibiotics and heavy metals, like the efflux pumps is a serious cause of concern as it is likely to aggravate co-selection pressure, leading to an increased dissemination of these resistance genes to fish and humans.

Multi-functional bioactive secondary metabolites derived from endophytic fungi of marine algal origin.

Endophytic fungi from marine macroalgae are endowed with various pharmacologically active metabolites. This study mined, identified and screened endophytic fungi (EF) isolated from marine algae from the west coast of South India for screening anticancer, antioxidant and antimicrobial secondary metabolite producers. Five EF isolated from sampled marine algae were identified using morphology and ITS based identification as Grammothele fuligo, Rigidoporus vinctus, Cystobasidium minutum, Candida railenensis and Pichia kudriavzevii. After culturing 20 days on PDA medium, the ethyl acetate extracts of Cystobasidium minutum showed potent antimicrobial activity against P. aeruginosa with an IC50 value of 458.7 ± 1.021 µg/mL whereas Pichia kudriavzevii extracts showed promising antioxidant activity (IC50 value of 65.78 ± 1.082 µg/mL, 38.74 ± 1.040 µg/mL and 32.01 ± 1.018 µg/mL for DPPH assay, ABTS assay and FRAP assay respectively) and high cytotoxic activity against MG63 cell line (IC50 = 145.1 ± 1.086 µg/mL, no activity against U87 cells). The phytochemical screening of the extracts unveiled the existence of diverse groups of secondary metabolites. Further, Gas Chromatography Mass Spectroscopy (GC-MS) analysis of the extract revealed the presence of compounds that are known to be antibacterial, antioxidant and cytotoxic. These results indicate that marine derived endophytes could be potent sources for multi-functional bioactive compounds and may find prospective application in pharmaceutical industry.

Insights into the response of mangrove sediment microbiomes to heavy metal pollution: Ecological risk assessment and metagenomics perspectives.

Rapid urbanisation and ensuing anthropogenic pollution lead to an escalated occurrence of heavy metals and metal-resistant bacteria in the soil ecosystem. Mangrove ecosystems are particularly vulnerable to heavy metal bioaccumulation and often act as metal sinks of the coastal areas. As a consequence, the microbial population in mangrove sediments develop multifarious metal tolerance mechanisms to combat metal toxicity. In this context, metagenomic investigation of two mangroves, viz. Mangalavanam and Puthuvypin from the heavily populated metropolitan city, Cochin (Central Kerala, India) was undertaken to discern the metal resistance functions and taxonomic diversity of the microbial consortia. Estimation of heavy metal content using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-MS) identified the abundance of zinc, chromium, nickel copper, lead, arsenic, and cadmium in the mangrove sediments. Ecological risk index values indicated high cadmium contamination of the two estuarine samples. Whole metagenome shotgun sequencing of the Central Kerala mangroves and comparative analysis with mangrove metal resistomes from other geographical regions revealed the prevalence of cobalt-zinc-cadmium resistance and preponderance of Proteobacteria in all the datasets. Cation efflux system protein CusA constituted the majority of the reads at the function level. Comparative analysis of taxonomy identified the dominance of Anaeromyxobacter, Geobacter, Pseudomonas, Candidatus Solibacter, and Pelobacter in the mangrove datasets. Non-metric multidimensional scaling analysis of the metal resistance genes depicted strong geographical clustering of the function and composition of metal resistant bacteria, suggesting a strong innate resilience of microbiome towards anthropogenic perturbations. More robust studies with intensive sampling will enhance our understanding of the occurrence, interactions, and functions of microbial heavy metal resistome in mangrove ecosystems.

Active bayerite underpinned Ag2O/Ag: an efficient antibacterial nanohybrid combating microbial contamination.

Active surfaces with bactericidal properties are of paramount importance in health care sector as a judicious approach to confront prevalent challenges presented by disastrous pathogenic infections and antibiotic-resistant microbes. Herein, we present Bayerite underpinned Ag2O/Ag (ALD), a nanohybrid with excellent antibacterial and antibiofilm functionalities against tested standard strains and clinical isolates. The multicomponent system coexists and complement each other with respect to phase and functionalities, demonstrated by XRD, XPS, and TEM analyses. In situ reduction of Ag+ ions to Ag0 over Bayerite as a stable bound phase is favoured by pH of the reaction, yielding 60-80% bound Ag protruding outwards facilitating active surface for interaction with microbes. ALD has a minimum inhibitory concentration (MIC) of 0.068 mg/ml against clinical isolates: Pseudomonas aeruginosa RRLP1, RRLP2, Acinetobactor baumannii C78 and C80. Disc diffusion assay demonstrated excellent antibacterial activity against standard strains (positive control: standard antibiotic disc, Amikacin). ALD incorporated PMMA films (5 and 10 wt%; PALD-5 and PALD-10) exhibited significant contact killing (99.9%) of clinical isolates in drop-test besides strong antibacterial activity (disc diffusion assay) comparable to that of ALD. ALD exemplified a dose (0.034 and 0.017 mg/ml) dependent biofilm inhibition (P < 0.001) and significant eradication of pre-formed biofilms (P < 0.001) by clinical isolates. PALD 5 and PALD 10 significantly declined the number of viable biofilm associated bacteria (99.9%) compared to control. Both ALD and PALD samples are proposed as green antibacterial materials with antibiofilm properties. Results also present ample opportunity to explore PALD as antibacterial and/or antibiofilm coating formulations.

In vitro efficiency evaluation of phage cocktail for biocontrol of Salmonella spp. in food products.

This study used a set of different bacteriophages to control contaminations of Salmonella spp., a major food pathogen. A cocktail of four phages designated based on host range and in vitro lytic assay showed a lower bacteriophage insensitive mutant frequency and considerable stability at 4 °C and 28 °C up to 60 days. The work evaluated the effectiveness of cocktail of four phages in reducing Salmonella spp. in four different food matrices (liquid egg, eggshell, milk, lettuce). A maximum of 1.7 log reduction in Salmonella spp. was achieved upon treatment of liquid eggs with phage cocktail for 72 h at 4 °C. In milk, the application of phage cocktail reduced recoverable Salmonella spp. by 1.9 log and 1.8 log at 28ºC (6 h) and 4ºC (72 h), respectively. A significant 2.9 log reduction of Salmonella spp. was obtained in eggshell after a 6 h incubation and Salmonella spp. was beyond detection level after 24 h at 28ºC. The application of cocktail also reduced Salmonella spp. beyond the detectable level in lettuce after 8 h at 28 °C. Our results indicated considerable stability of phages in different food matrices. Taken together, our findings establish the potential effectiveness of the bacteriophage cocktail as a biocontrol agent for Salmonella spp. in different food matrices.

Integration of heterogeneous photocatalysis and persulfate based oxidation using TiO2-reduced graphene oxide for water decontamination and disinfection.

Advanced oxidation processes (AOPs) which involve the generation of highly reactive free radicals have been considered as a promising technology for the decontamination of water from chemical and bacterial pollutants. In this study, integration of two major AOPs viz., heterogeneous photocatalysis involving TiO2-reduced graphene oxide (T-RGO) nanocomposite and activated persulfate (PS) based oxidation was attempted to remove diclofenac (DCF), a frequently detected pharmaceutical contaminant in water. The enhanced visible light responsiveness of T-RGO would facilitate the use of direct sunlight as a benign and cost effective source of energy for the photocatalytic activation. By combining PS based oxidation process with T-RGO mediated photocatalysis, a DCF removal efficiency of more than 98% was achieved within 30 min. The effect of operating parameters like PS concentration and pH on DCF removal was assessed. Radical scavenging experiments indicated that apart from radical oxidation involving •OH and SO 4 · - radicals, a non-radical oxidation pathway was also taking place in the degradation. The antibacterial properties of the integrated system were also evaluated using Escherichia coli and Staphylococcus aureus as representative bacteria. The presence of PS in the photocatalytic reaction system improved the antibacterial activity of the composite against the two strains studied. Cytotoxicity of T-RGO nanocomposite was assessed using human macrophage cell lines and the results showed that the composite is biocompatible and nontoxic at the recommended dosage for water treatment in the present study.

Optimization of PhysicoChemical Parameters for Production of Cytotoxic Secondary Metabolites and Apoptosis Induction Activities in the Culture Extract of a Marine Algal-Derived Endophytic Fungus Aspergillus sp.

The endophytic fungal community in the marine ecosystem has been demonstrated to be relevant source of novel and pharmacologically active secondary metabolites. The current study focused on the evaluation of cytotoxic and apoptosis induction potential in the culture extracts of endophytic fungi associated with Sargassum muticum, a marine brown alga. The cytotoxicity of the four marine endophytes, Aspergillus sp., Nigrospora sphaerica, Talaromyces purpureogenus, and Talaromyces stipitatus, was evaluated by the MTT assay on HeLa cells. Further, several physicochemical parameters, including growth curve, culture media, and organic solvents, were optimized for enhanced cytotoxic activity of the selected extract. The Aspergillus sp. ethyl acetate extract (ASE) showed maximum cytotoxicity on multiple cancer cell lines. Chemical investigation of the metabolites by gas chromatography-mass spectroscopy (GC-MS) showed the presence of several compounds, including quinoline, indole, 2,4-bis(1,1-dimethylethyl) phenol, and hexadecenoic acid, known to be cytotoxic in ASE. The ASE was then tested for cytotoxicity in vitro on a panel of six human cancer cell lines, namely, HeLa (cervical adenocarcinoma), MCF-7 (breast adenocarcinoma), Hep G2 (hepatocellular carcinoma), A-549 (lung carcinoma), A-431 (skin/epidermis carcinoma), and LN-229 (glioblastoma). HeLa cells were most vulnerable to ASE treatment with an IC50 value of 24 ± 2 µg/ml. The mechanism of cytotoxicity exhibited by the ASE was further investigated on Hela cells. The results showed that the ASE was capable of inducing apoptosis in HeLa cells through production of reactive oxygen species, depolarization of mitochondrial membrane, and activation of the caspase-3 pathway, which shows a possible activation of the intrinsic apoptosis pathway. It also arrested the HeLa cells at the G2/M phase of the cell cycle, eventually leading to apoptosis. Through this study, we add to the knowledge about the marine algae associated with fungal endophytes and report its potential for purifying specific compounds responsible for cytotoxicity.

A magainin-2 like bacteriocin BpSl14 with anticancer action from fish gut Bacillus safensis SDG14.

Bacteriocins are gaining utmost importance in antimicrobial and chemotherapy due to their diverse structure and activity. This study centres on magainin-2 like bacteriocin with anticancer action, produced by Bacillus safensis strain SDG14 isolated from gut of marine fish Sardinella longiceps. The purified bacteriocin designated as BpSl14 was thermostable and pH tolerant. The molecular weight of BpS114 was estimated to be 6061.2 Da using MALDI-ToF MS. The partial primary sequence was elucidated by peptide mass fingerprinting using MALDI MS/MS. The tertiary structure of the partial sequence was similar to that of two magainin-2 α-helices joined together by extended indolicidin. The BpSl14 protein inhibited the cells of lung carcinoma, one of the deadliest cancers. Docking studies conducted with DR5 and TGF-ß, two of the most prominent apoptotic receptors in adenocarcinoma, also proved the anti-apoptotic action of BpSl14.

Optical characterization and tunable antibacterial properties of gold nanoparticles with common proteins.

The interaction of three proteins, viz. Bovine Serum Albumin (BSA), Human Serum Albumin (HSA) and Hen Egg White Lysozyme (HEWL) with gold nanoparticles (GNPs) is investigated using surface plasmon resonance (SPR) spectroscopy, fluorescence spectroscopy and circular dichroism (CD). Size and morphology of the samples was established using Transmission Electron Microscopy (TEM) and stability studies was established using zeta potential analysis. The stability of protein-GNP complex was found to be greater than that of individual protein as well as individual GNPs. Also HEWL-GNP complex was more stable compared to the other protein complexes. Absorbance of proteins increases with increase in gold nanoparticle concentration due to the extension of peptide strands of protein and decrease in hydrophobicity of gold nanoparticles. A ground state complex is also formed which is evident from the moderate shift observed in the absorbance peaks. Apparent association constant was also determined from the absorption spectra and was found to be maximum for HEWL and minimum for HSA. Gold nanoparticles were found to act as quenchers and reduced the protein fluorescence intensity. Binding constant and number of binding sites were found to be maximum for HEWL and minimum for HSA. The temperature dependent fluorescence studies were also performed to calculate the thermodynamic parameters and to determine the nature of interaction between the proteins and gold nanoparticles. The circular dichroism studies elucidate the reason behind the maximum binding for HEWL and minimum binding for HSA. TGA analysis determined the thermal stability of the samples. Fluorescence lifetime studies indicate static quenching of proteins. Antibacterial activity of protein-gold nanoparticles was studied against four pathogens, viz. Bacillus pumilus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. HEWL exhibits a tunable antimicrobial activity against Pseudomonas aeruginosa due to the maximum binding of HEWL with gold nanoparticles. The study proposes a novel method for adjusting the antibacterial activity of HEWL against Pseudomonas aeruginosa when the resistance of this pathogen is a major issue in the chemotherapy of many infectious diseases. Thus the combination therapy of protein-gold nanoparticles could prove to be a new approach in medical field in the near future.

MFAP9: Characterization of an extracellular thermostable antibacterial peptide from marine fungus with biofilm eradication potential.

An extracellular thermostable antibacterial peptide designated as MFAP9 was purified from marine Aspergillus fumigatus BTMF9 by ammonium sulfate precipitation followed by ion exchange chromatography on a DEAE-sepharose column. The molecular weight of MFAP9 was found to be∼3 kDa in SDS-PAGE gel corresponding a single intensity peak in MALDI-TOF. The distinct peak with a retention time of 32.5 min appeared in high performance liquid chromatography (HPLC), further confirming the purity. Isoelectric focusing, two-dimensional gel electrophoresis and peptide mass fingerprinting were performed for the characterization of MFAP9. Functional analysis of purified MFAP9 exhibited strong antibacterial activity against Bacillus circulans (NCIM 2107) with MIC and MBC values of 0.525 µg/mL and 4.2 µg/mL, respectively. The in vitro antibiofilm effect of MFAP9 was analyzed against bacteria which have strong biofilm forming potential. The antibiofilm effect of MFAP9 treatment on Bacillus pumilus was examined using scanning electron microscopy. MFAP9 was found to be active at high temperatures and a wide range of pH (28). In addition, it showed varied sensitivity towards proteolytic enzymes. The peptide was nontoxic to human RBCs at higher concentrations. These results indicate that MFAP9 is an antibacterial peptide, suitable for the development of novel anti-infective agent with strong antibiofilm potential.