In situ and ex situ bioremediation of heavy metals: the present scenario

Enhanced population growth, rapid industrialization, urbanization and hazardous industrial practices have resulted in the development of environmental pollution in the past few decades. Heavy metals are one of those pollutants that are related to environmental and public health concerns based on their toxicity. Effective bioremediation may be accomplished through “ex situ” and “in situ” processes, based on the type and concentration of pollutants, characteristics of the site but is not limited to cost. The recent developments in artificial neural network and microbial gene editing help to improve “in situ” bioremediation of heavy metals from the polluted sites. Multi-omics approaches are adopted for the effective removal of heavy metals by various indigenous microbes. This overview introspects two major bioremediation techniques, their principles, limitations and advantages, and the new aspects of nanobiotechnology, computational biology and DNA technology to improve the scenario

Evaluation of predictive machine learning models for drug repurposing against delta variant of SARS-CoV-2 spike protein

Drug repurposing is a major approach used by researchers to tackle the COVID-19 pandemic which has been worsened by the current surge of delta variant in many countries. Though drugs like Remdesivir and Hydroxychloroquine have been repurposed, studies prove these drugs have insignificant effect in treatment. So, in this study, we use the already FDA approved database of 1615 drugs to apply semi-flexible and flexible molecular docking methods to calculate the docking scores and identify the best 20 potential inhibitors for our modelled delta variant spike protein RBD. Then, we calculate 2325 1-D and 2-D molecular descriptors and use machine-learning algorithms like K-Nearest Neighbor, Random Forest, Support Vector Machine and ensemble stacking method to build regression-based prediction models. We identify 15 best descriptors for the dataset all of which were found to be inversely correlated with ligand binding. With only these few descriptors, the models performed excellently with an area under curve (AUC) value of 0.952 in Regression Error Characteristic curve for ensemble stacking. Therefore, we comment that these 15 descriptors are the most important features for the binding of inhibitors to the spike protein and hence these should be studied properly in terms of drug repurposing and drug discovery

Immobilized enzymes as potent antibiofilm agent

Biofilm has been a point of concern in hospitals and various industries. They not only cause various chronic infections but are also responsible for the degradation of various medical appliances. Since the last decade, various alternate strategies are being adopted to combat the biofilm formed on various biotic and abiotic surfaces. The use of enzymes as a potent anti-fouling agent is proved to be of utmost importance as the enzymes can inhibit biofilm formation in an eco-friendly and cost-effective way. The physical and chemical immobilization of the enzyme not only leads to the improvement of thermostability and reusability of the enzyme, but also gains better efficiency of biofilm removal. Immobilization of amylase, cellobiohydrolase, pectinase, subtilisin A and β-N-acetyl-glucosaminidase (DspB) are proved to be most effective in inhibition of biofilm formation and removal of matured biofilm than their free forms. Hence, these immobilized enzymes provide greater eradication of biofilm formed on various surfaces and are coming up to be the potent antibiofilm agent.Universidade de Vigo/CISU

Microbiomics for enhancing electron transfer in an electrochemical system

In microbial electrochemical systems, microorganisms catalyze chemical reactions converting chemical energy present in organic and inorganic molecules into electrical energy. The concept of microbial electrochemistry has been gaining tremendous attention for the past two decades, mainly due to its numerous applications. This technology offers a wide range of applications in areas such as the environment, industries, and sensors. The biocatalysts governing the reactions could be cell secretion, cell component, or a whole cell. The electroactive bacteria can interact with insoluble materials such as electrodes for exchanging electrons through colonization and biofilm formation. Though biofilm formation is one of the major modes for extracellular electron transfer with the electrode, there are other few mechanisms through which the process can occur. Apart from biofilm formation electron exchange can take place through flavins, cytochromes, cell surface appendages, and other metabolites. The present article targets the various mechanisms of electron exchange for microbiome-induced electron transfer activity, proteins, and secretory molecules involved in the electron transfer. This review also focuses on various proteomics and genetics strategies implemented and developed to enhance the exo-electron transfer process in electroactive bacteria. Recent progress and reports on synthetic biology and genetic engineering in exploring the direct and indirect electron transfer phenomenon have also been emphasized

Functionalized Chitosan Nanomaterials: A Jammer for Quorum Sensing

The biggest challenge in the present-day healthcare scenario is the rapid emergence and spread of antimicrobial resistance due to the rampant use of antibiotics in daily therapeutics. Such drug resistance is associated with the enhancement of microbial virulence and the acquisition of the ability to evade the host’s immune response under the shelter of a biofilm. Quorum sensing (QS) is the mechanism by which the microbial colonies in a biofilm modulate and intercept communication without direct interaction. Hence, the eradication of biofilms through hindering this communication will lead to the successful management of drug resistance and may be a novel target for antimicrobial chemotherapy. Chitosan shows microbicidal activities by acting electrostatically with its positively charged amino groups, which interact with anionic moieties on microbial species, causing enhanced membrane permeability and eventual cell death. Therefore, nanoparticles (NPs) prepared with chitosan possess a positive surface charge and mucoadhesive properties that can adhere to microbial mucus membranes and release their drug load in a constant release manner. As the success in therapeutics depends on the targeted delivery of drugs, chitosan nanomaterial, which displays low toxicity, can be safely used for eradicating a biofilm through attenuating the quorum sensing (QS). Since the anti-biofilm potential of chitosan and its nano-derivatives are reported for various microorganisms, these can be used as attractive tools for combating chronic infections and for the preparation of functionalized nanomaterials for different medical devices, such as orthodontic appliances. This mini-review focuses on the mechanism of the downregulation of quorum sensing using functionalized chitosan nanomaterials and the future prospects of its applications

Nanodecoys: A Quintessential Candidate to Augment Theranostic Applications for a Plethora of Diseases

Nanoparticles (NPs) designed for various theranostic purposes have hugely impacted scientific research in the field of biomedicine, bringing forth hopes of a future revolutionized area called nanomedicine. A budding advancement in this area is the conjugation of various cell membranes onto nanoparticles to develop biomimetic cells called ‘Nanodecoys’ (NDs), which can imitate the functioning of natural cells. This technology of coating cell membranes on NPs has enhanced the working capabilities of nano-based techniques by initiating effective navigation within the bodily system. Due to the presence of multiple functional moieties, nanoparticles coated with cell membranes hold the ability to interact with complex biological microenvironments inside the body with ease. Although developed with the initial motive to increase the time of circulation in the bloodstream and stability by coating membranes of red blood cells, it has further outstretched a wide range of cell lines, such as mesenchymal stem cells, beta cells, thrombocytes, white blood cells, and cancer cells. Thus, these cells and the versatile properties they bring along with them open up a brand-new domain in the biomedical industry where different formulations of nanoparticles can be used in appropriate dosages to treat a plethora of diseases. This review comprises recent investigations of nanodecoys in biomedical applications

Strategies of Nanomaterial Application for Enhanced Wound Curing: An Overview

The biological process of healing of wounds deals with the regeneration of cells and is of utmost importance mainly because of the morphological and functional attributes of the tissue. One of the modern approaches is to use novel nanomaterial based wound dressings and other therapeutic treatments that have higher efficiency and specificity. Researchers all around the world have established the competence of various organic, inorganic or polymer-based and biogenically synthesized nanomaterials as a weapon for wound curing. Various matrices carrying nanoparticles like hydrogels, hydrocolloids are used in nano based drug delivery system. The biocompatibility, antimicrobial efficacy and sustained rate of drug delivery are the three main features that are considered for designing a nano drug for effective wound healing. The modification of the nanosized liposome using propylene glycol increases cell-permeation and retention in skin layer. Curcumin loaded liposomes show high anti-inflammatory effect, carbon nanodots (CNDs) and graphene oxide based nanosheets have also shown an immense importance in possessing high surface area. They also show potency in promoting fibroblast growth factors and collagen deposition for speedy recovery of wound. Moreover, the chronic wounds, that could not be cured by common antibiotics, can be addressed by nano based drugs not only for their easy penetration to deeper layer of tissues but also for their efficiency in killing some biofilm associated bacterial strains. Hence, nowadays nano based dressing materials are widely used for rapid recovery of wounds of various types

Development of a Rhodamine–Rhodanine-Based Fluorescent Mercury Sensor and Its Use to Monitor Real-Time Uptake and Distribution of Inorganic Mercury in Live Zebrafish Larvae

We introduce a new rhodamine–rhodanine-based “turn-on” fluorescent sensor (RR1) and describe its application for detection of mercury, including in solution, in live cells, and in a living vertebrate organism. The sensor RR1, which is a one-pot synthesis from rhodamine B, undergoes a rapid and irreversible 1:1 stoichiometric reaction with Hg²⁺ in aqueous medium. Using fluorescence correlation spectroscopy (FCS), RR1 was shown to detect the presence of as low as a 0.5 pM concentration of Hg²⁺. It may also lend itself to tagging with biomolecules and nanoparticles, leading to the possibility of organelle-specific Hg detection. Results of experiments with mammalian cells and zebrafish show that RR1 is cell and organism permeable and that it responds selectively to mercury ions over other metal ions. In addition, real-time monitoring of inorganic mercury ion uptake by cells and live zebrafish using this chemosensor shows that saturation of mercury ion uptake occurs within 20–30 min in cells and organisms. We also demonstrate the acquisition of high-resolution real-time distribution maps of inorganic mercury (Hg²⁺) in the zebrafish brain by using a simple fluorescence confocal imaging technique

Lactic Acid Bacteria (LAB): Autochthonous and Probiotic Microbes for Meat Preservation and Fortification

The enhanced concern of the consumers regarding the safety, quality of the food products, and avoidance of the use of chemical food preservatives has resulted in a breakthrough in biopreservation. This has resulted in the use of beneficial microbial species, including bacteria and their secondary metabolites, to enhance the shelf-life and quality of the food products. Meat preservation and fortification are among the biggest concerns, as they are relevant to the majority of food products. The chemical preservatives conventionally used in preserving meat and meat products possess several detrimental effects on the consumers. Thus, alternative strategies are needed to combat strategically in facilitating the shelf-life and quality. Lactic acid bacteria (LAB) are considered the safest organism and have a profound role in food and food-processing industries. The biofilm developed by the bacteria prevents the growth of various undesirable microorganisms on meat and meat products. Various studies depicted that LAB produces various antimicrobial metabolites that can act effectively on the food-degrading pathogens, rendering it safe and enhancing shelf-life. This review, thus, deals with the use of LAB as biopreservatives for enhancing the shelf-life of meat and meat products and helping its fortification