Search

Drought stress is considered to be a major factor responsible for reduced agricultural productivity, because it is often linked to other major abiotic stresses, such as salinity and heat stress. Understanding drought-tolerance mechanisms is important for crop improvement. Moreover, under drought conditions, it is possible that growth regulators are able to protect the plants. Brassinosteroids not only play a regulatory role in plant growth, but also organize defense mechanisms against various tresses. This study aimed to evaluate the effect of brassinolide on physio-biochemical amendment in two contrasting cultivars (drought-tolerant RH 725, and drought-sensitive RH 749) of Brassica juncea under drought stress. Two foliar sprayings with brassinolide (10 and 20 mg/L) were carried out in both cultivars (RH 725 and RH 749) at two stages—i.e., flower initiation, and 50% flowering—under stress conditions. The results clearly revealed that the activities of antioxidative enzymes and non-enzymatic antioxidants (carotenoids, ascorbic acid, and proline) increased significantly in RH 725 at 50% flowering, whereas 20 mg/L of brassinolide showed the most promising response. The different oxidative stress indicators (i.e., hydrogen peroxide, malondialdehyde, and electrolyte leakage) decreased to a significant extent at 20 mg/L of brassinolide spray in RH 725 at 50% flowering. This study indicates that brassinolide intensifies the physio-biochemical attributes by improving the antioxidant system and photosynthetic efficiency in RH 725 at 50% flowering. It is assumed that enhanced production of proline, improvement of the antioxidant system, and reduction in the amount of stress indicators impart strength to the plants to combat the stress conditions.

Chitosan is a cationic linear biopolymer that is produced by deacetylation of chitin by chitin deacetylase. This enzyme hydrolyses acetamido groups of N-acetyl glucosamine in chitin. Chitosan has immense potential especially in the field of agriculture, food and pharmaceuticals. In most of the countries, commercial exploitation of chitosan is predominantly done by conversion of chitin to chitosan by treating shellfish waste with alkali. The biological methods for extraction of chitosan were used as alternative for chemical methods. In the present study, 18 morphologically different fungal isolates, 17 bacteria and 3 actinomycete were isolated from soil and water samples. Out of these 38 strains, six isolates of fungi, two bacterial isolates and one actinomycete showed positive results by production of yellow color in the chitin agar media supplemented with p-nitroacetanilide as indicator.

Abstract An efficient and facile route for the synthesis of substituted imidazoles (10a-10g) has been developed by reacting substituted aldehydes (1–7), benzil (8) and ammonium acetate (9) in presence of solid supported acid catalyst viz. Rice Husk Ash.SO3H (RHA.SO3H) at room temperature. The purity of compounds was confirmed by melting point and thin layer chromatography. After the completion of reaction the crude product was recrystallized with ethylacetate to give pure samples (10a-10g) in good yield. All synthesized compounds (10a-10g) were characterized by 1HNMR and FTIR spectral techniques. The solid acid catalyst has been characterized by SEM, TEM and X-ray diffraction method. All synthesized compounds were tested in vitro herbicidal activity against Raphanus sativus L. seeds. The compounds (10a-10g) were also screened for their antifungal activity against Rhizoctonia solani and Aspergillus niger by poisoned food technique method. From bio evaluation data, it was found that compounds 10c and 10a were most active against Raphanus sativus L. seeds. Compound 4-(4,5-diphenyl-1H-imidazol-2-yl)phenol (10g) was found most active against R. solani fungus at highest concentration. Compound 2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (10f) has shown maximum percentage inhibition i.e. 71.89 against A. niger at 200 µg/mL concentration.

Psychrotrophs have the ability to survive in extreme conditions of lower temperature ranges from 0 °C to 20 °C. Psychrotrophic microorganisms mainly include bacteria, archaea and yeast, but among them, bacteria predominate in polar environment and archaea are more widespread in cold and deep ocean waters. They have evolved a variety of adaptation mechanisms such as gene expression modification and production of cold stress protein to cope up with stress induced at such a lower temperature. Cold active enzymes produced by psychrotrophs have wide applications in the food and pharmaceutical industry. Moreover these have wide applications in agriculture as they have the ability to promote plant growth at low temperature.

Microorganisms are ubiquitous in nature and are the backbones of all ecosystems. The halophilic microbes are extremely diverse that survive in high-saline environments. Most halophile (salt-loving) microbes belong to Bacteria, Archaea, and Eukarya, which are found in ponds, lake, deep-sea brines, etc. These microorganisms have adapted their surface and membrane structures to their highly ionic environments. They use two fundamentally different strategies in medium for balancing of their cytoplasm osmotically. The first strategy includes the accumulation of molar concentrations of KCl that requires adaptation mechanism of the intracellular enzymatic activity in the presence of salt to maintain proper conformation and activity of the proteins. The second strategy includes where salt is to be excluded from their cytoplasm and synthesized as well as accumulated organic solutes that could not be interfered with enzyme machinery. In recent years, halophiles have been attractive among researchers due to their adaptation mechanism in a wide range of salinities with potentially promising applications and a source of various bioactive compounds. Therefore, the saline and hypersaline environments could be more explored in the field of ecological niches which have been used for the discovery of bioactive compounds/metabolites. However, these halophiles are potential sources for a wide range of new therapeutic compounds. The aim of this introductory chapter is to provide brief perspectives on microbial ecology and highlight the applications in various fields and also understand the function and ecological roles of microbial community in saline environment. It also concludes putting the current status and future prospective with potential applications using advanced approaches derived from genomics and proteomics.

Sugarcane (Saccharum spp.) belonging to family Poaceae is a tropical perennial grass used widely for sugar production. Research scientists have discovered sugarcane as an alternative biofuel source to conventional petroleum fuels that lead to global warming. The sugars extracted from sugarcane can be easily fermented to produce ethanol. In addition, the bagasse (biomass remaining after the juice is extracted from the stalks) can be further used by sugar mills to generate steam and electricity. The current total global production of renewable fuels is 50 billion liters a year, and sugarcane alone accounts for about 40%, thus becoming a major contributor for biofuel production. The tremendous success of sugarcane industry to produce ethanol as biofuel in Brazil has also enhanced the interest in other parts of the world. With conventional technologies, sugarcane can yield several products from fiber to chemicals. But with the help of genetic recombination, sugarcane would roll to produce the novel biofuels more efficiently. Research scientists have identified the key enzymes that can hasten the process of ethanol production more powerfully. There is tremendous potential of sugarcane as a biofactory which can uplift both socioeconomic status of a country and sustainability of natural resources. Now, it’s time to augment weightage to produce biofuels in developing countries like India which would initiate rural development, create more job opportunities, and also save foreign exchange to great extent.