Indira P. Sarethy

Alkaliphilic bacteria: applications in industrial biotechnology

Alkaliphiles are interesting groups of extremophilic organisms that thrive at pH of 9.0 and above. Many of their products, in particular enzymes, have found widespread applications in industry, primarily in the detergent and laundry industries. While the enzymes have been a runaway success from the industrial point of view, many more products have been reported from alkaliphiles such as antibiotics and carotenoids. Less known are their potential for degradation of xenobiotics. They also play a key role in biogeocycling of important inorganic compounds. This review provides an insight into the huge diversity of alkaliphilic bacteria, the varied products obtained from them, and the need for further investigations on these interesting bacteria.

Green tea extract: possible mechanism and antibacterial activity on skin pathogens.

Camellia sinensis (tea) is known for its therapeutic properties (anti-inflammatory, anti-microbial, anti-tumour, anti-oxidative and anti-ageing). Although, anti-microbial properties of green tea have been studied, its role against bacterial strains related to skin infections and mechanism of action is not well understood. We focussed on exploring anti-microbial activity and the basic mechanism of aqueous green tea leaf extract on selected bacterial strains. Staphylococcus epidermidis, Micrococcus luteus, Brevibacterium linens, Pseudomonas fluorescens and Bacillus subtilis were found to be sensitive to green tea extract via disc diffusion assay (zone of inhibition ≥7 mm). Minimal inhibitory concentration (MIC) was determined via nitro blue tetrazolium (NBT) assay (0.156-0.313 mg/ml). Moreover, the aqueous extract was found to be not toxic to the Vero cell-line up to a concentration of 500 μg/ml. The effect of aqueous extract on adhesion of different bacteria to Vero cells indicated that it inhibits the adhesion at its MIC value.

Antioxidative peptides derived from food proteins

The search for natural antioxidants is an ongoing endeavour as an aid to combat the harmful effects of free radicals. Research advances in the past few decades have shown that, by controlled enzymatic hydrolysis, natural antioxidants can be produced from food proteins. In this chapter, the role of certain antioxidative peptides derived from food proteins is discussed in relation to their prospect in the prevention of oxidative stress. The molecular diversity of these food peptides is described together with their pharmacological effects and mechanisms of action in relation to antioxidation. The production of these peptides and the elucidation of their antioxidative peptides are also presented. Owing to their therapeutic potential, antioxidative peptides derived from food proteins can be incorporated as ingredients in functional foods, nutraceuticals and pharmaceuticals, where their biological activities may inhibit product oxidation or assist in the control and prevention of diseases induced by free radicals. However, further insightful research is needed to overcome certain scientific challenges and thereby increase and promote consumer acceptance of these natural antioxidants.

A Proposal for a Quality System for Herbal Products

Today, there is an increasing worldwide demand for botanicals. Developing countries heavily rely on plant-derived medicines for their primary healthcare. One reason amongst many is the relatively inexpensive process economics and the lack of stringent product governance associated with the exploitation of traditional plant medicines compared with modern medicine. Developed countries impose stringent good manufacturing practices and quality control measures on drug products derived from any manufacturing process, regardless of the primary raw material. However, several factors hamper the full-scale application of traditional plant medicines: lack of implementation of effective quality assurance in the manufacturing process; lack of traceability in the supply chain and associated value additions; and inefficient identification of molecular species that affect the therapeutic efficacy of the final product. There lacks an assessable, causative, and prognostic relationship between the raw materials, the manufacturing process and the final product quality. This article suggests some solutions that may be adopted by the phytodrug industry to widen its global reach and retain its credibility. Primarily among them is the implementation of hazards analysis and critical control point in the manufacturing process and employment of process analytical technology for ensuring minimal deviation from the manufacturing process of phytotherapeutics.

Paederia foetida — a promising ethno-medicinal tribal plant of northeastern India

The northeastern region of India constitutes one of the biodiversity hotspots of the world. The ethnic groups inhabiting this region practice their distinctive traditional knowledge systems using biodiversity for food, shelter and healthcare. Among the less-studied plants, Paederia foetida has been used by various ethnic tribes as food and medicine. Many of its therapeutic properties relate to the gastrointestinal system and suggest its potential utility for gastrointestinal ailments. This is a review of the ethnobotanical uses, phytochemistry and therapeutic properties of P. foetida compiled from various reports. P. foetida is promising as a remedy for life-style related conditions, especially treatment of ulcers. Its utility highlights the need for proper evaluation of tribal plants as medicines and the species could be considered for development of new drugs.

Antiproliferative Effect of Solanum nigrum on Human Leukemic Cell Lines

Solanum nigrum is used in various traditional medical systems for antiproliferative, antiinflammatory, antiseizure and hepatoprotective activities. We have evaluated organic solvent and aqueous extracts obtained from berries of Solanum nigrum for antiproliferative activity on leukemic cell lines, Jurkat and HL-60 (Human promyelocytic leukemia cells). The cell viability after the treatment with Solanum nigrum extract was measured by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. Results indicated increased cytotoxicity with increasing extract concentrations. Comparative analysis indicated that 50% inhibitory concentration value of methanol extract is the lowest on both cell lines.

Modern Taxonomy for Microbial Diversity

Microorganisms are actually composed of very different and taxonomically diverse groups of communities: archaea, bacteria, fungi and viruses. The members of these groups or taxa are distinct in terms of their morphology, physiology and phylogeny and fall into both prokaryotic and eukaryotic domains. They constitute a broad group of life system inhabiting the known ecosystems on earth: terrestrial and marine; including geographical locations considered to be extreme or inimical to life. The latter comprise of such areas as habitats with high salinity, alkalinity, acidity, high and low temperatures, high pressure, and high radiation. Considering the adaptability of microorganisms to grow and survive under varied physico-chemical conditions and their contribution in maintaining the balance in ecosystems, it is pertinent to catalogue their diversity as it exists. The inability to visualize them with the naked eye precludes effective classification. As such, using the available tools, microorganisms are broadly classified into prokaryotes and eukaryotes and subsequently into various taxonomical units depending on the resources available and required.

Saccharothrix sp. TD-093 from the Thar Desert, India: Metabolite Fingerprinting of Antimicrobial Compounds and in silico Analysis.

During a screening program for actinomycetes from underexplored and arid Thar Desert (India), TD-093 was isolated. The isolate was characterized based on 16S rDNA sequencing. Aqueous and organic solvent extracts of culture supernatant were investigated for antimicrobial activity. Bioactive fractions, after column chromatography separation, were subjected to GC-MS analysis. Based on 16S rDNA sequence result, isolate TD-093 showed nearest match to Saccharothrix (96%) and is a potential new species. Aqueous and organic solvent extracts showed antimicrobial activity against Staphylococcus epidermidis, Micrococcus luteus, Pseudomonas fluorescens, and Escherichia coli as well as clinical isolates (Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii). GC-MS metabolite fingerprinting resulted in 32 compounds belonging to fatty acid, hydrocarbon, alcohol, aldehyde, amide, ester, ketone, disulfide, and nitrile chemical groups. Combination analyses of the compounds based on retention time, similarity index, mass ion spectra, and retention indices—observed and calculated, showed that many of the compounds could be presumed to be novel. Further, four compounds showed retention indices that have not been documented in databases. In silico analysis (using software Prediction of Activity of Spectra for Substances) of compounds predicted by GC-MS data showed that 21 compounds had potential antibacterial activity.

Evaluation of Micropropagation System of Bacopa monnieri L. in Liquid Culture and Its Effect on Antioxidant Properties

Nodal explants of Bacopa monnieri were cultured in a solid Murashige and Skoog (MS) medium containing 1 mg L−1 kinetin, transferred after 30 days to a liquid MS medium of the same composition in 100 mL and 250 mL Erlenmeyer flasks (with 10 mL and 50 mL medium, respectively) and Phyta Jars (with 10 mL medium) and subcultured every 7 d. Shoot doubling time was estimated and the total antioxidant capacity of aqueous extracts from liquid-cultured and acclimatized plants was studied. In the solid medium, 5 rooted shoots/explant were produced after ~20 days, with shoot doubling time of 7.99 days; in liquid media, 36–75 rooted shoots were produced with shoot doubling time of 0.91–1.17 days. Aqueous extracts of acclimatized plants showed 10-fold higher total antioxidant capacity compared to in vitro liquid cultured plantlets.

Analyzing Functional Microbial Diversity: An Overview of Techniques

Abstract Ecosystem functioning is, to a large extent, dependent on the activities of microorganisms. Though comprising the largest fraction of living organisms in terms of numbers and biomass, their importance in maintenance of habitats, ecological recycling of nutrients, waste and other matter, and their crucial role in interactions between biotic and abiotic components of the environment demands that their functional role in various habitats be elucidated clearly. While the output of such studies are scattered, a limitation has also been that 99% of microorganisms are believed to belong to the uncultivable fraction. This makes it imperative that this fraction should also be addressed in functional diversity studies. The interplay between taxonomic and functional diversity, where taxonomy, to a large extent, is associated with function, mandates that the chapter also emphasize on assessment of taxonomy. The current chapter focuses on the various techniques available to study cultivable and uncultivable microorganisms (with emphasis on work pertaining to bacteria), from their functional diversity point of view.