Gamut of glycolytic enzymes in vascular smooth muscle cell proliferation: Implications for vascular proliferative diseases

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the media of the blood vessels and are responsible for maintaining vascular tone. Emerging evidence confirms that VSMCs possess high plasticity. During vascular injury, VSMCs switch from a "contractile" phenotype to an extremely proliferative "synthetic" phenotype. The balance between both strongly affects the progression of vascular remodeling in many cardiovascular pathologies such as restenosis, atherosclerosis and aortic aneurism. Proliferating cells demand high energy requirements and to meet this necessity, alteration in cellular bioenergetics seems to be essential. Glycolysis, fatty acid metabolism, and amino acid metabolism act as a fuel for VSMC proliferation. Metabolic reprogramming of VSMCs is dynamically variable that involves multiple mechanisms and encompasses the coordination of various signaling molecules, proteins, and enzymes. Here, we systemically reviewed the metabolic changes together with the possible treatments that are still under investigation underlying VSMC plasticity which provides a promising direction for the treatment of diseases associated with VSMC proliferation. A better understanding of the interaction between metabolism with associated signaling may uncover additional targets for better therapeutic strategies in vascular disorders.

Protective effect of olopatadine hydrochloride against LPS-induced acute lung injury: via targeting NF-κB signaling pathway

BACKGROUND

Morbidity and mortality rates associated with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are high (30-40%). Nuclear factor-kappa B (NF-κB) is a transcription factor, associated with transcription of numerous cytokines leading to cytokine storm, and thereby, plays a major role in ALI/ARDS and in advanced COVID-19 syndrome.

METHODS

Considering the role of NF-κB in ALI, cost-effective in silico approaches were utilized in the study to identify potential NF-κB inhibitor based on the docking and pharmacokinetic results. The identified compound was then pharmacologically validated in lipopolysaccharide (LPS) rodent model of acute lung injury. LPS induces ALI by altering alveolar membrane permeability, recruiting activated neutrophils and macrophages to the lungs, and compromising the alveolar membrane integrity and ultimately impairs the gaseous exchange. Furthermore, LPS exposure is associated with exaggerated production of various proinflammatory cytokines in lungs.

RESULTS

Based on in silico studies Olopatadine Hydrochloride (Olo), an FDA-approved drug was found as a potential NF-κB inhibitor which has been reported for the first time, and considered further for the pharmacological validation. Intraperitoneal LPS administration resulted in ALI/ARDS by fulfilling 3 out of the 4 criteria described by ATS committee (2011) published workshop report. However, treatment with Olo attenuated LPS-induced elevation of proinflammatory markers (IL-6 and NF-κB), oxidative stress, neutrophil infiltration, edema, and damage in lungs. Histopathological studies also revealed that Olo treatment significantly ameliorated LPS-induced lung injury, thus conferring improvement in survival. Especially, the effects produced by Olo medium dose (1 mg/kg) were comparable to dexamethasone standard.

CONCLUSION

In nutshell, inhibition of NF-κB pathway by Olo resulted in protection and reduced mortality in LPS- induced ALI and thus has potential to be used clinically to arrest disease progression in ALI/ARDS, since the drug is already in the market. However, the findings warrant further extensive studies, and also future studies can be planned to elucidate its role in COVID-19-associated ARDS or cytokine storm.

Insights to Phenylalanine Ammonia Lyase (PAL) and Secondary Metabolism in Orchids: An in silico Approach

The phenylalanine ammonia lyase (PAL) catalyses the first step of phenylpropanoid metabolic pathway which leads to the biosynthesis of a diverse group of secondary metabolites. Orchids serve as a rich source of metabolites and the availability of genome or transcriptome for selected orchid species provides an opportunity to analyse the PAL genes in orchids. In the present study, 21 PAL genes were characterized using bioinformatics tools in nine orchid species (Apostasia shenzhenica, Cypripedium formosanum, Dendrobium catenatum, Phalaenopsis aphrodite, Phalaenopsis bellina, Phalaenopsis equestris, Phalaenopsis lueddemanniana, Phalaenopsis modesta and Phalaenopsis schilleriana). Multiple sequence alignment confirmed the presence of PAL-specific conserved domains (N-terminal, MIO, core, shielding and C-terminal domain). All these proteins were predicted to be hydrophobic in nature and to have cytoplasmic localisation. Structural modelling depicted the presence of alpha helices, extended strands, beta turns and random coils in their structure. Ala-Ser-Gly triad known for substrate binding and catalysis of MIO-domain was found to be completely conserved in all the proteins. Phylogenetic study showed that the PALs of pteridophytes, gymnosperms and angiosperms clustered together in separate clades. Expression profiling showed tissue-specific expression for all the 21 PAL genes in the various reproductive and vegetative tissues which suggested their diverse role in growth and development. This study provides insights to the molecular characterization of PAL genes which may help in developing biotechnological strategies to enhance the synthesis of phenylpropanoids in orchids and other heterologous systems for pharmaceutical applications.

Recent advances in pharmaceutical and biotechnological applications of lignin-based materials

Lignin, a versatile and abundant biomass-derived polymer, possesses a wide array of properties that makes it a promising material for biotechnological applications. Lignin holds immense potential in the biotechnology and pharmaceutical field due to its biocompatibility, high carbon content, low toxicity, ability to be converted into composites, thermal stability, antioxidant, UV-protectant, and antibiotic activity. Notably, lignin is an environmental friendly alternative to synthetic plastic and fossil-based materials because of its inherent biodegradability, safety, and sustainability potential. The most important findings related to the use of lignin and lignin-based materials are reported in this review, providing an overview of the methods and techniques used for their manufacturing and modification. Additionally, it emphasizes on recent research and the current state of applications of lignin-based materials in the biomedical and pharmaceutical fields and also highlights the challenges and opportunities that need to be overcome to fully realize the potential of lignin biopolymer. An in-depth discussion of recent developments in lignin-based material applications, including drug delivery, tissue engineering, wound dressing, pharmaceutical excipients, biosensors, medical devices, and several other biotechnological applications, is provided in this review article.

Green synthesis of lignin-based nanoparticles as a bio-carrier for targeted delivery in cancer therapy

Polymeric magnetic nanoparticles have shown higher efficacy in cancer diagnosis and treatment than conventional chemotherapies. Lignin is an abundantly available natural polymer that can be selectively modified using a rapidly expanding toolkit of biocatalytic and chemical reactions to yield 'intelligent' theranostic-nanoprobes. We aim to valorize lignin to develop a natural polymeric-magnetic-nano-system for the targeted delivery of methotrexate. In the current study, we synthesized nanoparticles of lignin and iron oxide with methotrexate using a new approach of anti-solvent precipitation with ultrasonication. The ensuing nanoparticles are magnetic, smooth, polyhedral with characteristic dimension of 110-130 nm. The drug loading and encapsulation efficiencies were calculated to be 66.06 % and 64.88 %, respectively. The nanoparticles exhibit a concentration-dependent release of methotrexate for the initial 24 h, followed by sustained release. Moreover, formulation is non-hemolytic and scavenges radicals owing to the antioxidant property of lignin. Additionally, methotrexate delivered using the nanoparticles exhibited higher cytotoxicity in cellular-viability assays employing breast cancer and macrophage cell lines compared to the pure form of the drug. Synergistic action of lignin, iron oxide, and methotrexate contribute to enhanced caspase-3 activity and reduced glutathione levels in the breast cancer cells, as well as elevated internalization of the drug on account of increased receptor-mediated endocytosis.

Synthesis, biological evaluation and in silico studies of 2-aminoquinolines and 1-aminoisoquinolines as antimicrobial agents

The current study reports synthesis of 2-aminoquinolines and 1-aminoisoquinolines derivatives and their characterization. Further, in vitro studies were conducted to determine antimicrobial activities. Compound 3 h showed maximum activity against B. subtilis (IC₅₀: 0.10±0.02 µM) and E. coli (IC₅₀: 0.13±0.01 µM) whereas compound 3i showed higher antimicrobial activity against E. coli (IC₅₀: 0.11±0.01) and C. viswanathii (IC₅₀: 0.10±0.05 µM). Safety profiles of the most potent derivatives were evaluated utilizing cell viability assay using RAW 264.7 and HeLa cell lines and in vitro hemolytic assay was carried out freshly isolated RBC from healthy rat. Furthermore, in silico studies, like molecular docking, binding free energy calculations and ADME predictions were done to get the best lead candidates. Additionally, molecular dynamic simulation for 100 ns was performed to know stability of protein and ligand complex. The active compounds were found to be non-toxic and non-hemolytic and hold great promise to become newer antimicrobial agents.

Polyketide synthases (PKSs) of secondary metabolism: in silico identification and characterization in orchids

Type III polyketide synthases (PKSs) catalyse the formation of an array of polyketides with diverse structures that play an important role in secondary metabolism in plants. This group of enzymes is encoded by a multigene family, the Type III polyketide synthase (PKS) gene family. Vast reserves of secondary metabolites in orchids make these plants suitable candidates for research in the area. In this study, genome-wide searches lead to the identification of five PeqPKS, eight DcaPKS and six AshPKS genes in Phalaenopsis equestris, Dendrobium catenatum and Apostasia shenzhenica, respectively. All the members showed the presence of two characteristic conserved domains (Chal_sti_synt_N and Chal_sti_synt_C) and were generally localised in the cytoplasm. The phylogenetic analysis led to the classification of these proteins into two groups: CHS (chalcone synthase (CHS) and non-CHS. A single protein in P. equestris and two proteins each in D. catenatum and A. shenzhenica clustered within the CHS clade. The majority of the genes exhibited similar structural patterns with a single intron. Expression profiling revealed the tissue-specific expression of these genes with high expression in reproductive tissues for most genes. A number of stress-responsive cis-regulatory elements were predicted, noteworthy amongst these are, ABRE and CGTCA that are chiefly responsible for responding to abscisic acid and methyl jasmonate, respectively. Our study provides a reference framework for future studies involving functional elucidation of PKS genes and biotechnological production of polyketides.Communicated by Ramaswamy H. Sarma.

Chitosan Hydrogels with Embedded Thermo- and pH-Responsive Microgels as a Potential Carrier for Controlled Release of Drugs

We report a promising strategy based on chitosan (CS) hydrogels and dual temperature- and pH-responsive poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-MAA) microgels to facilitate release of a model drug, moxifloxacin (MFX). In this protocol, first, the microgels were prepared using a free radical copolymerization method, and subsequently, these carboxyl-group-rich soft particles were incorporated inside the hydrogel matrix using an EDC-NHS amidation method. Interestingly, the resulting microgel-embedded hydrogel composites (MG-HG) acting as a double barrier system largely reduced the drug release rate and prolonged the delivery time for up to 68 h, which was significantly longer than that obtained using microgels or hydrogels alone (20 h). On account of the dual-responsive features of the embedded microgels and the variation of water-solubility of drug molecules as a function of pH, MFX could be released in a controllable manner by regulating the temperature and pH of the delivery medium. The release kinetics followed a Korsmeyer-Peppas model, and the drug delivery mechanism was described by Fickian diffusion. Both the gel precursors and the hydrogel composites exhibited low cytotoxicity against mammalian cell lines (HeLa and HEK-293) and no deleterious hemolytic activity up to a certain higher concentration, indicating excellent biocompatibility of the materials. Thus, the unprecedented combination of modularity of physical properties caused by soft particle entrapment, unique macromolecular architecture, biocompatibility, and the general utility of the stimuli-responsive polymers offers a great promise to use these composite materials in drug delivery applications.

A Walk Through the Maze of Secondary Metabolism in Orchids: A Transcriptomic Approach

Orchids have a huge reservoir of secondary metabolites making these plants of immense therapeutic importance. Their potential as curatives has been realized since times immemorial and are extensively studied for their medicinal properties. Secondary metabolism is under stringent genetic control in plants and several molecular factors are involved in regulating the production of the metabolites. However, due to the complex molecular networks, a complete understanding of the specific molecular cues is lacking. High-throughput omics technologies have the potential to fill up this lacuna. The present study deals with comparative analysis of high-throughput transcript data involving gene identification, functional annotation, and differential expression in more than 30 orchid transcriptome data sets, with a focus to elucidate the role of various factors in alkaloid and flavonoid biosynthesis. Comprehensive analysis of the mevalonate (MVA) pathway, methyl-d-erythritol 4-phosphate (MEP) pathway, and phenylpropanoid pathway provide specific insights to the potential gene targets for drug discovery. It is envisaged that a positive stimulation of these pathways through regulation of pivotal genes and alteration of specific gene expression, could facilitate the production of secondary metabolites and enable efficient tapping of the therapeutic potential of orchids. This further would lay the foundation for developing strategies for genetic and epigenetic improvement of these plants for development of therapeutic products.

Nanostructured lipid carriers: a promising drug carrier for targeting brain tumours

Background

In recent years, the field of nanotechnology and nanomedicine has transformed the pharmaceutical industry with the development of novel drug delivery systems that overcome the shortcomings of traditional drug delivery systems. Nanostructured lipid carriers (NLCs), also known as the second-generation lipid nanocarriers, are one such efficient and targeted drug delivery system that has gained immense attention all across due to their myriad advantages and applications. Scientific advancements have revolutionized our health system, but still, brain diseases like brain tumour have remained formidable owing to poor prognosis and the challenging drug delivery to the brain tissue. In this review, we highlighted the application and potential of NLCs in brain-specific delivery of chemotherapeutic agents.

Main body

NLCs are lipid-based formulations with a solid matrix at room temperature and offer advantages like enhanced stability, low toxicity, increased shelf life, improved drug loading capacity, and biocompatibility over other conventional lipid-based nanocarriers such as nanoemulsions and solid lipid nanoparticles. This review meticulously articulates the structure, classification, components, and various methods of preparation exemplified with various research studies along with their advantages and disadvantages. The concept of drug loading and release has been discussed followed by a brief about stability and strategies to improve stability of NLCs. The review also summarizes various in vitro and in vivo research studies on NLCs encapsulated with cytotoxic drugs and their potential application in brain-specific drug delivery.

Conclusion

NLCs are employed as an important carrier for the delivery of food, cosmetics, and medicines and recently have been used in brain targeting, cancer, and gene therapy. However, in this review, the applications and importance of NLCs in targeting brain tumour have been discussed in detail stating examples of various research studies conducted in recent years. In addition, to shed light on the promising role of NLCs, the current clinical status of NLCs has also been summarized.

Graphical Abstract

Development of nanostructured lipid carriers as a promising tool for methotrexate delivery: physicochemical and in vitro evaluation

The aim of the present study is to fabricate the stable nanostructured lipid carriers (NLCs) using biocompatible excipients for the encapsulation of Methotrexate (MTX), a chemotherapeutic agent for breast cancer treatment. MTX has restricted clinical applications owing to its low solubility, non-specific targeting and adverse side effects. Glyceryl Monostearate (GMS) and Miglyol 812 (MI1) were chosen as solid and liquid lipids, respectively, for the fabrication of NLCs, and the influence of variation of solid and liquid composition was investigated. The prepared NLCs exhibited long-term stability and spherical shape morphology as characterized by electron microscopy. The internal structure of fabricated NLCs was arranged into cubic crystalline as confirmed by small-angle X-ray scattering (SAXS) analysis. MTX's encapsulation efficiency of ∼85 ± 0.9%. and sustained in vitro release of MTX ∼ 52% ± 3.0 in 24 h was achieved. Classical molecular dynamics (MD) simulations were performed to study the structural stability of the MTX encapsulated NLCs. Hemolysis carried out on the NLCs showcased the biosafety of the formulation under the tolerance limit (<10%). Further, the MTT assay demonstrates that MTX-loaded NLCs exhibited toxicity against HeLa and MCF-7 cell lines as compared to blank NLCs. The finding demonstrates NLCs as promising vehicles for MTX delivery to address cancer.Communicated by Ramaswamy H. Sarma.

A Review on Repurposed Drugs and Vaccine Trials for Combating SARS CoV-2

BACKGROUND

The novel coronavirus disease 2019 (COVID-19), emerged in Wuhan, China in December 2019 and then spread worldwide rapidly. The records from World Health Organisation (WHO), Centres of Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) backup the fact that no medications have proven to be completely effective for prevention or treatment of SARS-CoV-2. The clinical trials are underway for many repurposed, investigational drugs and vaccine candidates. BioNTech and Pfizer Inc, Moderna, Gamaleya institute and University of Oxford (collaboration with AstraZeneca) announced positive results in the Phase 3 interim analyses of vaccine trials in November 2020. Twelve countries have approved Pfizer- BioNTech COVID-19 vaccine for emergency use, as of December 2020.

OBJECTIVE

The objective was to summarize the repurposed/investigational drugs, their mechanism of action, and rationale for their use in COVID-19 treatment. The article also aimed to summarize the vaccine trials that are currently undergoing across the globe.

METHODS

In order to find the content for review, studies defining COVID-19 chronology, repurposed drugs along with their mode of action and potential vaccine trials were studied and summarized.

RESULTS AND CONCLUSION

The article summarizes potential therapeutic candidates (repurposed and investigational agents) for SARS-CoV-2, their possible mechanism of action and discussion related to their involvement in recent clinical trials. Innovative vaccine platform technologies are also highlighted that are recently being used in the vaccine production pipeline.

A Review on Rheumatoid Arthritis Interventions and Current Developments

Rheumatoid arthritis is a chronic autoimmune disorder characterized by inflammation, swelling, and joint destruction primarily affecting the peripheral joints. In recent years, RA has become an alarming concern affecting more than 1.5% of the population worldwide. The majority of the drugs in clinical trials for rheumatoid arthritis are immunomodulatory. The development of novel drugs for RA is impending and scientists are exploring new strategies through various innovative approaches for RA drug development. Treat-to-target and window of opportunity hypothesis are the new approaches that are used to treat, improve outcomes, and prevent long-term use of ineffective therapy, respectively. Novel therapeutic agents (e.g. GM-CSF inhibitors, Matrix metalloproteinase inhibitors) and delivery systems (e.g., Liposomes, Superparamagnetic iron oxide nano particles (SPIONs)) are under investigation for more target based therapy with reduced side effects and toxicity. The new drug discovery and repositioning of previously FDA-approved drugs are also being considered for chronic inflammatory disorder. The review encompasses a vast array of information, including genetics, etiology, clinical symptoms, current treatment, and newer therapeutics approaches, focused on the development of RA interventions. The introduction of the bioinformatics-based approach in RA has also been significantly discussed in the review. This review provides a general understanding of the challenges and uncertainties in the treatment of RA and summarizes the evolving scenario as well as innovative approaches taken into consideration for drug development in rheumatoid arthritis.

Facially Amphiphilic Cholic Acid-Lysine Conjugates as Promising Antimicrobials

The emergence of multidrug-resistant microbes is a significant health concern posing a constant need for new antimicrobials. Membrane-targeting antibiotics are promising candidates with reduced ability of microbes to develop resistance. In the present investigation, the principal reason behind choosing cholic acid as the crucial scaffold lies in the fact that it has a facially amphiphilic nature, which provides ample opportunity to refine the amphiphilicity by linking the amino acid lysine. A total of 16 novel amphipathic cholic acid derivatives were synthesized by sequentially linking lysine to C3-β-amino cholic acid methyl ester to maintain the hydrophobic/hydrophilic balance, which could be the essential requirement for the antimicrobial activity. Among the synthesized conjugates, a series with fluorenyl-9-methoxycarbonyl moiety attached to cholic acid via lysine linker showed promising antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. A pronounced effect of increase in lysine residues was noted on the observed activity. The lead compounds were found to be active against drug-resistant bacterial and fungal clinical isolates and also improved the efficacy of antifungal agents amphotericin B and voriconazole. Membrane-permeability studies demonstrated the ability of these compounds to induce membrane damage in the tested microbes. The active conjugates did not show any hemolytic activity and were also found to be nontoxic to the normal cells as well as the examined cancer cell lines. The observed antimicrobial activity was attributed to the facial amphiphilic conformations, hydrophobic/hydrophilic balance, and the overall charge on the molecules.

A mild and metal-free synthesis of 2- and 1-alkyl/aryl/dialkyl-aminoquinolines and isoquinolines

A simple synthetic strategy has been developed for the synthesis of 2- and 1-alkyl/aryl/dialkylaminoquinolines and isoquinolines from the easily available quinoline and isoquinoline-N-oxides, different amines, triflic anhydride as activating agent and acetonitrile as solvent in a one-pot reaction under metal-free conditions at 0 °C to room temperature.

A stimulus-responsive, in situ-forming, nanoparticle-laden hydrogel for ocular drug delivery

Most medications targeting optic neuropathies are administered as eye drops. However, their corneal penetration efficiencies are typically < 5%. There is a clear, unmet need for novel transcorneal drug delivery vehicles. To this end, we have developed a stimulus-responsive, in situ-forming, nanoparticle-laden hydrogel for controlled release of poorly bioavailable drugs into the aqueous humor of the eye. The hydrogel is formulated as a composite of hyaluronic acid (HA) and methylcellulose (MC). The amphiphilic nanoparticles are composed of poly(ethylene oxide) (PEO) and poly(lactic acid) (PLA). Experimental design aided the identification of hydrogel composition and nanoparticle content in the formulation, and the formulation reliably switched between thixotropy and temperature-dependent rheopexy when it was tested in a rheometer under conditions that simulate the ocular surface, including blinking. These properties should ensure that the formulation coats the cornea through blinking of the eyelid and facilitate application of the medication as an eye drop immediately prior to the patient’s bedtime. We subsequently tested the efficacy of our formulation in whole-eye experiments by loading the nanoparticles with cannabigerolic acid (CBGA). Our formulation exhibits over a 300% increase in transcorneal penetration over control formulations. This work paves the way for the introduction of novel products targeting ocular diseases to the market.

Metagenomic discovery of a novel transaminase for valorization of monoaromatic compounds

The profitability of next-generation biorefineries is acutely contingent on the discovery and utilization of biocatalysts that can valorize lignin. To this end, the metabolic catalogues of diverse microbiota have been mined previously using functional metagenomics in order to identify biocatalysts that can selectively degrade lignin into monoaromatic compounds. Herein, we have further improved the valorization factor of biorefining by deploying functional metagenomics toward the identification of a novel transaminase that can selectively functionalize lignin-derived monoaromatics to produce value-added feedstocks for pharmaceutical synthesis. We implemented a high-throughput colorimetric assay using o-xylylenediamine as the amino donor and successfully identified a transaminase that utilizes the canonical cofactor, pyridoxal 5'-phosphate, to aminate as many as 14 monoaromatic aldehydes and ketones. We subsequently identified the optimal conditions for enzyme activity towards the most favoured amino acceptor, benzaldehyde, including temperature, pH and choice of co-solvent. We also evaluated the specificity of the enzyme towards a variety of amino donors, as well as the optimal concentration of the most favoured amino donor. Significantly, the novel enzyme is markedly smaller than typical transaminases, and it is stably expressed in E. coli without any modifications to its amino acid sequence. Finally, we developed and implemented a computational methodology to assess the activity of the novel transaminase. The methodology is generalizable for assessing any transaminase and facilitates in silico screening of enzyme-substrate combinations in order to develop efficient biocatalytic routes to value-added amines. The computational pipeline is an ideal complement to metagenomics and opens new possibilities for biocatalyst discovery.

An Improved Whole-Cell Biosensor for the Discovery of Lignin-Transforming Enzymes in Functional Metagenomic Screens

The discovery and utilization of biocatalysts that selectively valorize lignocellulose is critical to the profitability of next-generation biorefineries. Here, we report the development of a refactored, whole-cell, GFP-based biosensor for high-throughput identification of biocatalysts that transform lignin into specialty chemicals from environmental DNA of uncultivable archaea and bacteria. The biosensor comprises the transcriptional regulator and promoter of the emrRAB operon of E. coli, and the configuration of the biosensor was tuned with the aid of mathematical model. The biosensor sensitively and selectively detects vanillin and syringaldehyde, and responds linearly over a wide detection range. We employed the biosensor to screen 42 520 fosmid clones comprising environmental DNA isolated from two coal beds and successfully identified 147 clones that transform hardwood kraft lignin to vanillin and syringaldehyde.

Cheminformatic Analysis of Antimalarial Chemical Space Illuminates Therapeutic Mechanisms and Offers Strategies for Therapy Development

The clear and present danger of malaria, which has been amplified in recent years by climate change, and the progressive thinning of our drug arsenal over the past two decades raise uncomfortable questions about the current state and future of antimalarial drug development. Besides suffering from many of the same technical challenges that affect drug development in other disease areas, the quest for new antimalarial therapies is also hindered by the complex, dynamic life cycle of the malaria parasite, P. falciparum, in its mosquito and human hosts, and its role thereof in the elicitation of drug resistance. New strategies are needed in order to ensure economical and expeditious development of new, more efficacious treatments. In the present study, we employ open-source cheminformatics tools to analyze the chemical space traversed by approved antimalarial drugs and promising candidates at various stages of development to uncover insights that could shape future endeavors in the field. Our scaffold-centric analysis reveals that the antimalarial chemical space is disjointed and segregated into a few dominant structural groups. In fact, the structures of antimalarial drugs and drug candidates are distributed according to Pareto's principle. This structural convergence can potentially be exploited for future drug discovery by incorporating it into bioinformatics workflows that are typically employed for solving problems in structural biology. Significantly, we demonstrate how molecular scaffold hunting can be applied to unearth putative mechanisms of action of drugs whose activities remain a mystery, and how scaffold-centric analysis of drug space can also provide a recipe for combination therapies that minimize the likelihood of emergence of drug resistance, as well as identify areas on which to focus efforts. Finally, we also observe that over half of the molecules in the antimalarial space bear no resemblance to other molecules in the collection, which suggests that the pharmacobiology of antimalarial drugs has not been entirely surveyed.

The Impending Renaissance in Discovery & Development of Natural Products

Antibiotics are wonder drugs. Unfortunately, owing to overuse, antibiotic resistance is now a serious problem. Society now finds itself in the post-antibiotic era, and the threat of infectious diseases is on the rise. New antibiotics are sorely needed. There is strong evidence that suggests natural products are an attractive source of new antimicrobials. They posses desirable structural and chemical properties that make them potent thearpeutics. However, steep tehnological challenges associated with screening and manufacturing these molecules has stifled the discovery, development and marketing of new antimicrobials. To this end, two recent scientific developments are poised to redress this situation. The recent development of metagenomics and ancillary high-throughput screening technologies has exponentiated the volume of useful genetic sequence information that can be screened for antimicrobial discovery. These approaches have been instrumental in the discovery of new antibiotics from soil and marine environments. Secondly, a new manufacturing paradigm employing metabolic engineering as its engine has greatly accelerated the path to market for these molecules, in addition to improving the atom and energy economy of antimicrobial manufacturing. We outine these developments in this review, and provide a perspective on integrating next-generation approaches such as metagenomics and metabolic engineering with traditional methodologies for discovering and manufacturing antimicrobial natural products in order to unleash a rennaissance in the discovery and development of antimicrobials.

Synergism between microwave irradiation and enzyme catalysis in transesterification of ethyl-3-phenylpropanoate with n-butanol

Lipase catalyzed transesterification was investigated to study the synergistic effect of microwave irradiation and enzyme catalysis. Transesterification of ethyl-3-phenylpropanoate with n-butanol was chosen as the model reaction using immobilized enzymes such as Novozyme 435, Lipozyme RMIM and Lipozyme TL IM with microwave irradiation. Novozyme 435 was the best catalyst. The effect of various parameters affecting the conversion and initial rates of transesterification were studied to establish kinetics and mechanism. There is synergism between enzyme catalysis and microwave irradiation. The analysis of initial rate data and progress curve data showed that the reaction obeys the Ping-Pong bi-bi mechanism with inhibition by n-butanol. The theoretical predictions and experimental data match very well. These studies were also extended to other alcohols such as 2-phenyl-1-propanol, n-octanol, benzyl alcohol, iso-amyl alcohol, 2-hexanol and 2-pentanol under otherwise similar conditions.

Stereo-selective conversion of mandelonitrile to (R)-(−)-mandelic acid using immobilized cells of recombinant Escherichia coli

Immobilized cells of a recombinant Escherichia coli expressing nitrilase from Pseudomonas putida were used to catalyze the hydrolysis of mandelonitrile (2-hydroxy-2-phenylacetonitrile) to (R)-(−)-mandelic acid. The cells had been immobilized by entrapment in an alginate matrix. Conditions for the hydrolysis reaction were optimized in shake flasks and in a packed bed reactor. In shake flasks the best conditions for the reaction were a temperature of 40 °C, pH 8, biocatalyst bead diameter of 4.3 mm, sodium alginate concentration in the gel matrix of 2 % (w/v, g/100 mL), a cell dry mass concentration in the bead matrix of 20 mg/mL, an initial substrate concentration of 50 mM and a reaction time of 60 min. Under these conditions, the conversion of mandelonitrile was nearly 95 %. In the packed bed reactor, a feed flow rate of 20 mL/h at a substrate concentration of 200 mM proved to be the best at 40 °C, pH 8, using 4.3 mm beads (2 % w/v sodium alginate in the gel matrix, 20 mg dry cell concentration per mL of gel matrix). This feed flow rate corresponded to a residence time of 0.975 h in the packed bed.

Soft-tissue CT changes in pelvic venous thrombosis

The computed tomographic (CT) changes in the soft tissues of the pelvis are presented in three patients with pelvic venous thrombosis. Pelvic venous thrombosis may lead to swelling of surrounding muscles and may present as a pelvic mass. This mass can simulate a tumor clinically, radiographically, and sonographically, but its origin and cause can be demonstrated by CT. Proper understanding of such changes may prevent an erroneous diagnosis of enlarged pelvic lymph nodes or an inflammatory or neoplastic mass.