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The major activity of β-amylase (BMY) is the production of maltose by the hydrolytic degradation of starch. BMY is found to be produced by some plants and few microorganisms only. The industrial importance of the enzyme warrants its application in a larger scale with the help of genetic engineering, for which the regulatory mechanism is to be clearly understood. In plants, the activities of BMY are regulated by various environmental stimuli including stress of drought, cold and heat. In vascular plant, Arabidopsis sp. the enzyme is coded by nine BAM genes, whereas in most bacteria, BMY enzymes are coded by the spoII gene family. The activities of these genes are in turn controlled by various compounds. Production and inhibition of the microbial BMY is regulated by the activation and inactivation of various BAM genes. Various types of transcriptional regulators associated with the plant- BMYs regulate the production of BMY enzyme. The enhancement in the expression of such genes reflects evolutionary significance. Bacterial genes, on the other hand, as exemplified by Bacillus sp and Clostridium sp, clearly depict the importance of a single regulatory gene, the absence or mutation of which totally abolishes the BMY activity.

Phytocompounds are long known for their therapeutic uses due to their competence as antimicrobial agents. The antimicrobial activity of these bioactive compounds manifests their ability as an antibiofilm agent and is thereby proved to be competent to treat the widespread biofilm-associated chronic infections. The rapid development of antibiotic resistance in bacteria has made the treatment of these infections almost impossible by conventional antibiotic therapy, which forced a switch-over to the use of phytocompounds. The present overview deals with the classification of a huge array of phytocompounds according to their chemical nature, detection of their target pathogen, and elucidation of their mode of action.

Cellulose is considered to be one of the most underutilized biomass available on earth. These cellulosic resources, if utilized as the precursor of food, feed and biofuel can meet up the ever-increasing demands for food and energy. Since cellulase is an enzyme complex, fermentation of cellulose from agro-wastes and industrial effluents is a complex event. The physicochemical parameters are generally optimized in "one at a time" mode in fed-batch culture. But with the advent of time, statistical and mathematical modelling is used, like response surface methodology (RSM), artificial neural network (ANN), machine learning algorithm, and genetic algorithm to improve enzyme production. In bioreactor-based cellulase production, a LabVIEW-based intelligent system for monitoring bio-processing is used for the optimization of the target parameters. RSM and ANN are high-quality prediction mathematical models but ANN shows its superiority in context to the fitting of data as well as its estimation capabilities. The difference of ANN concerning RSM is its requirement of a large number of trained data. This review provides a comprehensive study of literature in context to various advanced mechanisms for optimization of cellulase production.

The novel COVID-19 Pandemic has affected the World terribly causing death of more than 500,000 people, affecting over 200 countries and demolishing the World Economy. As prior studies and researches suggest, cancer patients are generally considered more prone to the viral infections owing to various relevant reasons. Therefore, a systematic analysis of cancer patients affected by COVID-19 is highly required. In this paper, data from several performed experiments in many multi-centred studies are included and evaluated to draw conclusions, specifically focusing on the age-matched non-cancer patients confirmed with COVID-19. The results suggests that COVID-19 patients with cancer had higher risks in all severe outcomes [1]. Patients with hematologic cancer, lung cancer, or with metastatic cancer (stage IV) had minimum survival chances. Patients with non-metastatic cancer also showed similar results to those observed in patients without cancer. Patients who received surgery had low mortality rates. Again, patients undergoing radiotherapy did not possess any differences which is significant [2]. These results clearly suggest that patients with cancer are more prone to SARS-CoV-2 viral infection.

An antimicrobial is an agent that destroys microorganisms or hinders their growth. They can be grouped according to the microorganisms they act primarily against. Microbes, mainly bacteria, develop a number of ways to check the action of these antimicrobials, which is often genetically controlled. One of such way is achievement of biofilm-mediated antimicrobial resistance. Biofilms are the sessile groups of organism that possess the property of adhering to the biotic and abiotic surfaces by synthesizing extracellular polymeric substances (EPS) that not only provide nourishment to the developing microcolonies but also render resistance against antibiotics and antimicrobial agents. Varieties of molecular mechanisms are responsible for the development of high-degree recalcitrance that determines the characteristics of biofilm. The mechanisms that are involved in these processes are various types of interactions between the antimicrobials and the biofilm matrix that reduces the rate of growth, and various gene expressions result in the formation of antibiotic resistance.

Biofilm-forming microbes are the root cause of various almost incurable chronic, nosocomial, and medical device-associated infections that are of serious concern in present-day condition. With the advent of science, a number of diseases, disorders, and abnormalities can be effectively managed by the use of various medical devices including pacemakers, vascular catheters, chronic hemodialysis catheters, prosthetic heart valves, and prosthetic joints. But the effectiveness of these medical devices is seriously hampered by the biofilm grown aggressively on these devices. The interactions existing between the microbial cells, host, and the biomaterials result in the development, persistence, and failure in treating these device-associated infections. The present chapter would focus on various medical devices-associated biofilm infections that are affecting the host immune system leading to chronic infections and failure of the objective of this implant operation.

Bacterial biofilm plays a major role in causing diseases as the indwelling bacteria within the biofilm are resilient to host immune system and various types of antibiotics. Various chronic infections of clinical origin such as cystic fibrosis (CF), urinary tract infections (UTI), pertussis, otitis media (OM), bacterial prostatitis (BP), mastitis, etc. are the types of biofilm-associated chronic infections. It is observed that the microorganisms involved in the abovementioned diseases can also cause acute infections in biological environments. Thus deciphering the transition from acute to chronic infections by understanding the bacterial strategy, mode of growth and spread within host will serve the purpose of solving the unanswered question: how the same microbe can cause acute infections in some environmental setting while chronic in others. This chapter tries to bridge the gap by understanding the host responses towards acute and chronic infections, recurrence of infections and development of various treatment strategies.

Silver nanoparticles (AgNPs) are among the various types of the metallic nanoparticles considered to possess antimicrobial potential. The use of biogenic sources as a potential reducing agent for synthesis nanoparticle is promptly increasing in comparison to physical and chemical methods. Amongst the biogenic sources, fungi are more preferred microorganisms to use for AgNPs synthesis as they are easy to culture and can control the size and morphology of the synthesized nanoparticles and help in low-cost large-scale production. The use of fungi for AgNPs synthesis is a rapid, environmentally safe, and cost-effective approach for vector control strategies in the future. Fungi can act as an effective agent in comparison to other microorganisms as it has the ability of producing higher amount of enzymes and proteins with the potential for synthesizing nanoparticles. Fungi-mediated synthesized nanoparticles possess coatings of biomolecules, which increases their activity. Organisms like Aspergillus flavus, Rhizopus sp., and Fusarium oxysporum were reported to possess extracellular material or biomass, which helps in the reduction of silver ions to AgNPs. This chapter focusses solely on fungi-mediated AgNPs synthesis, with their preferred physico-chemical parameters, their mode of action, and their applications in various modern aspects.

Legumes are the group of predominant nitrogen fixers that act as a source of wide variety of secondary metabolites that act as a line of defence against various bacterial, fungal, parasitic and predatory species. The symbiotic bacterial species establishes a syntopic interaction by quorum sensing and develop a biofilm that help is building up of the symbiotic relation with the plant. This association not only helps in the mode of nitrogen fixation but also helps in increasing the bioactive contents along with various types of abiotic components found in soil. These bioactive compounds have wide therapeutic potential, as significantly used as anti-aging, antimicrobial, antibiofilm, antioxidant, antidiabetic, anti-inflammatory and cardioprotective agents. The compounds also act as antiangiogenic agent and prevent the proliferation of disease causing pathogens. Hence, legumes not only help in sustainable development of plant and agriculture, but also possess significant therapeutic potential to promote human health. The present article thus reviews the contribution of legumes towards nitrogen fixation to facilitate plant growth and discusses their bioactive compounds having beneficial role in regulating human health.

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.