Novel application of Nerium leaf and Image J software in drop collapse assay for rapid screening of biosurfactant producing microorganisms

484-492Biosurfactants are attractive molecules with varied applicationsmainly oil degradation, emulsification, bioremediation, therapeutics and conjugation of nanoparticles. The existing screening methods for biosurfactants are inappropriate and too tedious. Here, we have explored a novel approach with drop collapse assay wherein we replaced the microtiter well plate with the naturally hydrophobic Nerium (Nerium oleander L.) leaf. The stability of beaded drops on the leaf indicates negative phenomenon, and spreading of drop indicates positive phenomenon for surfactant property, as confirmed by the measuring drop diameter using Image J software. Fifty five bacterial cultures isolated from oil contaminated site were screened through this novel approach which revealed that the isolates DNM49 (6.75±0.29 mm), DNM50 (7.45±0.19 mm) and DNM51 (6.14±0.82 mm) were the best in terms of surface tension reduction, although thirty other isolates were also found to be positive. A gradation of activity in terms of surface tension reduction was also established based on drop diameter. The results demonstrated promising application of Nerium leaf with Image J software in drop collapse assay as an eco-friendly and cost-effective and technically authenticated alternative to the existing assays

Novel application of Nerium leaf and Image J software in drop collapse assay for rapid screening of biosurfactant producing microorganisms

Biosurfactants are attractive molecules with varied applicationsmainly oil degradation, emulsification, bioremediation, therapeutics and conjugation of nanoparticles. The existing screening methods for biosurfactants are inappropriate and too tedious. Here, we have explored a novel approach with drop collapse assay wherein we replaced the microtiter well plate with the naturally hydrophobic Nerium (Nerium oleander L.) leaf. The stability of beaded drops on the leaf indicates negative phenomenon, and spreading of drop indicates positive phenomenon for surfactant property, as confirmed by the measuring drop diameter using Image J software. Fifty five bacterial cultures isolated from oil contaminated site were screened through this novel approach which revealed that the isolates DNM49 (6.75±0.29 mm), DNM50 (7.45±0.19 mm) and DNM51 (6.14±0.82 mm) were the best in terms of surface tension reduction, although thirty other isolates were also found to be positive. A gradation of activity in terms of surface tension reduction was also established based on drop diameter. The results demonstrated promising application of Nerium leaf with Image J software in drop collapse assay as an eco-friendly and cost-effective and technically authenticated alternative to the existing assays

Characterization and Cytotoxicity of Pseudomonas Mediated Rhamnolipids Against Breast Cancer MDA-MB-231 Cell Line

A biosurfactant producing bacterium was identified as Pseudomonas aeruginosa DNM50 based on molecular characterization (NCBI accession no. MK351591). Structural characterization using MALDI-TOF revealed the presence of 12 different congeners of rhamnolipid such as Rha-C8-C8:1, Rha-C10-C8:1, Rha-C10-C10, Rha-C10-C12:1, Rha-C16:1, Rha-C16, Rha-C17:1, Rha-Rha-C10:1-C10:1, Rha-Rha-C10-C12, Rha-Rha-C10-C8, Rha-Rha-C10-C8:1, and Rha-Rha-C8-C8. The radical scavenging activity of rhamnolipid (DNM50RL) was determined by 2, 3-diphenyl-1-picrylhydrazyl (DPPH) assay which showed an IC50 value of 101.8 mu g/ ml. The cytotoxic activity was investigated against MDA-MB-231 breast cancer cell line by MTT (4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide) assay which showed a very low IC50 of 0.05 mu g/ ml at 72 h of treatment. Further, its activity was confirmed by resazurin and trypan blue assay with IC50 values of 0.01 mu g/ml and 0.64 mu g/ ml at 72 h of treatment, respectively. Thus, the DNM50RL would play a vital role in the treatment of breast cancer targeting inhibition of p38MAPK

Exploring the opinions of the YouTube visitors towards advertisements and its influence on purchase intention among viewers

Online retailing as a mode of transaction has been dominating the market through web-based advertisements since the beginning of the 21st century, replacing the role of mass media. India, being a populous country, has witnessed a rapid increase in online customers in recent years. Nonetheless, there are not many in-depth studies analyzing the opinion of Indian netizens on online advertisements and its influence on decision-making process and purchase intention. Thus, the current study explored opinion about advertisements and its role in purchasing intentions among young YouTube visitors, using qualitative research design. The data were collected from 50 participants (23 males and 27 females) who have reported engaging in YouTube for a minimum of 30 minutes per day, through a semi-structured interview. Data were analyzed and interpreted through thematic analysis. Four themes and 10 sub-themes were identified. The main themes include the relevance of the advertisement (personalization, future purchases, and trials), disinterest (personal testimonies and inattentiveness), subjective distress (recurrent advertisements, placement of advertisements and length of advertisement), and information and entertainment (introduction to the product, distinctiveness, and creativity). From the results, it can be observed that YouTube users have both positive and negative opinions and corresponding intentions about the purchase