SARS-CoV-2 seroprevalence in the city of Hyderabad, India in early 2021.

Background: COVID-19 emerged as a global pandemic in 2020, spreading rapidly to most parts of the world. The proportion of infected individuals in a population can be reliably estimated via serosurveillance, making it a valuable tool for planning control measures. Our serosurvey study aimed to investigate SARS-CoV-2 seroprevalence in the urban population of Hyderabad at the end of the first wave of infections.

Substrate structure and computation guided engineering of a lipase for omega-3 fatty acid selectivity.

Enrichment of omega-3 fatty acids (ɷ-3 FAs) in natural oils is important to realize their health benefits. Lipases are promising catalysts to perform this enrichment, however, fatty acid specificity of lipases is poor. We attempted to improve the fatty acid selectivity of a lipase from Geobacillus thermoleovorans (GTL) by two approaches.

X-ray structure and characterization of a thermostable lipase from Geobacillus thermoleovorans.

Thermo-alkalophilic bacterium, Geobacillus thermoleovorans secrets many enzymes including a 43 kDa extracellular lipase. Significant thermostability, organic solvent stability and wide substrate preferences for hydrolysis drew our attention to solve its structure by crystallography. The structure was solved by molecular replacement method and refined up to 2.

Efficiency of dual siRNA-mediated gene therapy for intervertebral disc degeneration (IVDD).

Background Context: One of the common causes of low back pain is intervertebral disc degeneration. The pathophysiology of disc degeneration involves apoptosis of nucleus pulposes cells and degradation of extra cellular matrix (ECM). Caspase 3 plays a central role in apoptosis and the ADAMTS5 (A Disintegrin and Metalloproteinase with Thrombospondin motifs 5) gene plays a critical role in ECM degradation.

Aurora kinase B siRNA-loaded lactoferrin nanoparticles potentiate the efficacy of temozolomide in treating glioblastoma.

Aim: To investigate the efficacy of lactoferrin nanoparticles (LfNPs) in delivering siRNA across the blood-brain barrier to treat glioblastoma multiforme (GBM) and with an additional objective of potentiation of conventional temozolomide (TMZ) chemotherapy.

Methods: Aurora kinase B (AKB) siRNA-loaded nanoparticles (AKB-LfNPs) were prepared with milk protein, lactoferrin, by water in oil emulsion method. AKB-LfNPs were tested in cell lines and in GBM orthotopic mouse model with and without TMZ treatment.

Chlorin e6 loaded lactoferrin nanoparticles for enhanced photodynamic therapy.

Photosensitizer (PS) mediated Photodynamic Therapy (PDT) is a preferred treatment modality for certain cancers. Some of the factors limiting the expansion of PDT to other clinical conditions are the aggregation of hydrophobic PS in aqueous media and the inefficient biodistribution of photosensitizers. Formulations containing the PS have overcome some of the limitations by controlling aggregation-dependent quenching of PS and by improving the biodistribution of PS.

Draft Genome Sequence of Entomopathogenic Strain Lak 1210, an Alkaliphilic Chitin Degrader.

We announce here the draft genome sequence of strain Lak 1210, isolated from mangrove soil. This alkaliphilic strain is an efficient chitin degrader and has the ability to control insects and inhibit phytopathogenic fungi. The assembly consists of 5,082,926 bp, with 4,321 protein-coding sequences and a GC content of 41.

Overcoming blood brain barrier with a dual purpose Temozolomide loaded Lactoferrin nanoparticles for combating glioma (SERP-17-12433).

Targeted delivery of drugs to the brain is challenging due to the restricted permeability across the blood brain barrier (BBB). Gliomas are devastating cancers and their positive treatment outcome using Temozolomide (TMZ) is limited due to its short plasma half-life, systemic toxicity and limited access through the blood-brain barrier (BBB). Nanoparticles made of Lactoferrin (Lf) protein, have been shown to enhance the pharmacological properties of drugs.

Combinatorial Labeling Method for Improving Peptide Fragmentation in Mass Spectrometry.

Annotation of peptide sequence from tandem mass spectra constitutes the central step of mass spectrometry-based proteomics. Peptide mass spectra are obtained upon gas-phase fragmentation. Identification of the protein from a set of experimental peptide spectral matches is usually referred as protein inference.

Mutational probing of protein aggregates to design aggregation-resistant proteins.

Characterization of amorphous protein aggregates may offer insights into the process of aggregation. Eleven single amino acid mutants of lipase (LipA of Bacillus subtilis) were subjected to temperature-induced aggregation, and the resultant aggregates were characterized for recovery of activity in the presence of guanidinium chloride (GdmCl). Based on activity recovery profiles of the aggregates, the mutants could be broadly assigned into four groups.

Selective Enrichment of Omega-3 Fatty Acids in Oils by Phospholipase A1.

Omega fatty acids are recognized as key nutrients for healthier ageing. Lipases are used to release ω-3 fatty acids from oils for preparing enriched ω-3 fatty acid supplements. However, use of lipases in enrichment of ω-3 fatty acids is limited due to their insufficient specificity for ω-3 fatty acids.

Photosensitizer and peptide-conjugated PAMAM dendrimer for targeted in vivo photodynamic therapy.

Challenges in photodynamic therapy (PDT) include development of efficient near infrared-sensitive photosensitizers (5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine [PS]) and targeted delivery of PS to the tumor tissue. In this study, a dual functional dendrimer was synthesized for targeted PDT. For targeting, a poly(amidoamine) dendrimer (G4) was conjugated with a PS and a nitrilotriacetic acid (NTA) group.

A computational search for lipases that can preferentially hydrolyze long-chain omega-3 fatty acids from fish oil triacylglycerols.

Consumption of long-chain omega-3 fatty acids is known to decrease the risk of major cardiovascular events. Lipases, a class of triacylglycerol hydrolases, have been extensively tested to concentrate omega-3 fatty acids from fish oils, under mild enzymatic conditions. However, no lipases with preference for omega-3 fatty acids selectivity have yet been discovered or developed.

Targeted in vivo photodynamic therapy with epidermal growth factor receptor-specific peptide linked nanoparticles.

In targeted photodynamic therapy (tPDT), photosensitizers (PS) are targeted to disease tissue to reduce the dosage of PS and in addition to reduce the photo damage to the non-target tissue. We synthesized iron oxide nanoparticles (NP) armored with tumor targeting peptide and PS for targeted PDT. Chitosan covered Fe3O4 NPs (30 nm) were deposited with gold NPs to generate two distinct chemical surfaces.

Engineering lipase A from mesophilic Bacillus subtilis for activity at low temperatures.

Loops or unordered regions of a protein are structurally dynamic and are strongly implicated in activity, stability and proteolytic susceptibility of proteins. Diminished activity of proteins at lower temperatures is considered to be due to compromised dynamics of the protein at lower temperatures. To evolve an active mesophilic lipase (Bacillus subtilis) at low temperatures, we subjected all the loop residues (n = 88) to site saturation mutagenesis (SSM).

Binding of bis-ANS to Bacillus subtilis lipase: a combined computational and experimental investigation.

8-Anilino-1-naphthalene sulfonate (ANS) and its covalent dimer bis-ANS are widely used for titrating hydrophobic surfaces of proteins. Interest to understand the nature of interaction of these dyes with proteins was seriously pursued. However as the techniques used in these studies varied, they often provided varied information regarding stoichiometry, binding affinity, actual binding sites etc.

Lipase in aqueous-polar organic solvents: activity, structure, and stability.

Studying alterations in biophysical and biochemical behavior of enzymes in the presence of organic solvents and the underlying cause(s) has important implications in biotechnology. We investigated the effects of aqueous solutions of polar organic solvents on ester hydrolytic activity, structure and stability of a lipase. Relative activity of the lipase monotonically decreased with increasing concentration of acetone, acetonitrile, and DMF but increased at lower concentrations (upto ~20% v/v) of dimethylsulfoxide, isopropanol, and methanol.

Engineering the loops in a lipase for stability in DMSO.

Nearly 65% of the surface of a lipase, from Bacillus subtilis, is occupied by the loops. Since the loops are dynamic components of a protein, located on the surface and are tolerant to substitutions, we subjected all 91 amino acids of the loops to site saturation mutagenesis to identify mutations that improve the stability and activity of lipase in dimethyl sulfoxide (DMSO). Based on a novel screening system, we have identified six positions in the lipase, from a population of 18,000 transformants that contributed to higher activity in DMSO.

Role of active site rigidity in activity: MD simulation and fluorescence study on a lipase mutant.

Relationship between stability and activity of enzymes is maintained by underlying conformational flexibility. In thermophilic enzymes, a decrease in flexibility causes low enzyme activity while in less stable proteins such as mesophiles and psychrophiles, an increase in flexibility is associated with enhanced enzyme activity. Recently, we identified a mutant of a lipase whose stability and activity were enhanced simultaneously.

Targeting human epidermal growth factor receptor 2 by a cell-penetrating peptide-affibody bioconjugate.

Cell-penetrating peptide (CPP)-based delivery systems represent a strategy that facilitates DNA import efficiently and non-specifically into cells. To introduce specificity, we devised an approach that combines a cell-penetrating peptide, TAT-Mu (TM) and a targeting ligand, an HER2 antibody mimetic-affibody (AF), designated as TMAF to deliver nucleic acids into the cells. In this study, we synthesized TMAF protein and its truncated versions, i.

Synthesis and transfection efficiency of cationic oligopeptide lipids: role of linker.

In the design of new cationic lipids for gene transfection, the chemistry of linkers is widely investigated from the viewpoint of biodegradation and less from their contribution to the biophysical properties. We synthesized two dodecyl lipids with glutamide as the backbone and two lysines to provide the cationic headgroup. Lipid 1 differs from Lipid 2 by the presence of an amide linkage instead of an ester linkage that characterizes Lipid 2.

In vitro evolved non-aggregating and thermostable lipase: structural and thermodynamic investigation.

Rational and in vitro evolutionary approaches to improve either protein stability or aggregation resistance were successful, but empirical rules for simultaneous improvement of both stability and aggregation resistance under denaturing conditions are still to be ascertained. We have created a robust variant of a lipase from Bacillus subtilis named "6B" using multiple rounds of in vitro evolution. T(m) and optimum activity temperature of 6B is 78 °C and 65 °C, respectively, which is ~22 °C and 30 °C higher than that of wild-type lipase.

Stabilizing effect of polyols is sensitive to inherent stability of protein.

In studies on polyol-mediated protein stabilization, the polyols are the preferred variable and less importance is given to the intrinsic properties of the protein used. We investigated the stabilizing effects of glycerol on three in vitro evolved lipase mutants with varying stabilities and also in a broad pH range of 3.3-12.

Stability curves of laboratory evolved thermostable mutants of a Bacillus subtilis lipase.

Shape of the protein stability curves changes to achieve higher melting temperature. Broadly, these changes have been classified as upward shift (increased G(s)), rightward shift (increase in T(s)) and flattening of the stability curves (decrease in C(p)). Comparative studies on homologous mesophilic-thermophilic protein pairs highlighted the differential contribution of these three strategies amongst proteins.

Thermally denatured state determines refolding in lipase: mutational analysis.

Irreversibility of thermally denatured proteins due to aggregation limits thermodynamic characterization of proteins and also confounds the identification of thermostable mutants in protein populations. Identification of mutations that prevent the aggregation of unfolded proteins provides insights into folding pathways. In a lipase from Bacillus subtilis, evolved by directed evolution procedures, the irreversibility due to temperature-mediated aggregation was completely prevented by a single mutation, M137P.