Electrochemical behavior, antimicrobial activities, and effect of temperature on micellization of imidazolium monomeric surfactants.

In the present study, we herein report the conductance behavior, effect of temperature, and chain-length of two environmentally friendly imidazolium cationic capric and stearic surfactants. The conductance behavior has been carried out in aqueous solvent (H2O) at four different temperatures such as 24 °C, 29 °C, 34 °C, and 39 °C. The normal micelles were formed in an aqueous solvent and critical micelle concentration (CMC) can be estimated through conductivity parameters. The expected dependency of the CMC on the alkyl chain length of the 3-(2-(decanoyloxy)ethyl)-1-methyl-1H-imidazol-3-ium-bromide and 3-(2-(octadecanoyloxy)ethyl)-1-methyl-1H-imidazol-3-ium-bromide was demonstrated. It was observed that the graphs of molar conduct activity v/s square root were not linear, which specifies that the synthesized surfactants behave as weak electrolytes in the dilute solutions. The electrochemical characterization of capric and stearic surfactant modified SPCE was studied in 1mM K3FeCN6 solution. The CS/SPCE and SS/SPCE were shown elevated sensitivity, high stability, and excellent conductivity. Moreover, the antimicrobial behaviors of the synthesized imidazolium cationic surfactants versus various microbial strains were evaluated. Results showed that capric surfactant demonstrated high antibacterial activity against Escherichia coli (MIC > 31.5 µg/mL).

Carotenoid cleavage dioxygenases (HD-CCD1A and B) contribute as strong negative regulators of ß-carotene in Indian bread wheat (cv. HD2967).

Wheat (Triticum aestivum L.) is the most common cereal crop that is considered to be deficient in provitamin A carotenoids. Carotenoids are prone to degrade into apocarotenoids by the activity of carotenoid cleavage dioxygenases (CCDs). Hence, in this study, multiple CCDs were cloned from commercial Indian wheat cultivar HD2967 to understand their role in provitamin A carotenoids degradation. The homoeolog specific expression of HD-CCD1 and HD-CCD4 at different grain filling stages revealed the higher expression of transcripts arising from the A and B subgenomes of HD-CCD1. Furthermore, the grain development stages showed a strong negative correlation of HD-CCD1A (r = - 0.969) and B (r = - 0.970) homoeologs expression to that of ß-carotene accumulation. It suggested that they could be potentially involved in deciding the turn-over of ß-carotene in wheat grain. Three-dimensional (3D) structures for all six homoeologs of HD-CCD1 and HD-CCD4 were predicted using maize VP14 template to gain better insight into their molecular mechanism. Ramachandran plot assessment revealed that ~ 90% of residues are in the most favoured region. Docking studies with various carotenoid substrates revealed the higher affinity of HD-CCD1A and B for ß-carotene and ß-cryptoxanthin. Bacterial complementation analysis validated the functional role of all six homoeologs with HD-CCD1B showing the highest activity followed by HD-CCD1A for ß-carotene degradation. Results of this study provide valuable insights into the characteristics of HD-CCDs in wheat and thereby justifying them (HD-CCD1A and B) as the candidate genes for employing genome editing tools for developing ß-carotene enriched wheat grains. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02775-y.

Hyper-production of taxol from Aspergillus fumigatus, an endophytic fungus isolated from Taxus sp. of the Northern Himalayan region.

Taxol® (generic name Paclitaxel) is a chemotherapeutic drug, effective against head, neck, breast, lung, bladder, ovary, and cervix cancers. Rising demands in chemotherapy and limited supply of natural taxol have ultimately increased the cost of the drug. Semi synthesis using taxol precursors is not able to meet the global supply and has intensified the need to find alternative ways of taxol production. In the present study, 34 different endophytes were isolated from Taxus sp. collected from Shimla, Himachal Pradesh (India). Primary screening of taxol-producing fungi was carried out based on the presence of dbat gene, essential for the taxol biosynthetic pathway. A fungal isolate TPF-06 was screened to be a taxol-producing strain based on the PCR amplification results. It was characterized and identified as Aspergillus fumigatus by 18S rRNA (Accession No. KU-837249). Multiple sequence alignment (MSA) of nuclear ribosomal internal transcribed spacer (ITS) region and phylogenetic analysis confirmed that strain belonged to A. fumigatus clade (Accession No. MF-374798) and is endophytic in nature. Presence of taxol was detected and quantified by High-Performance Liquid Chromatography (HPLC) and characterized by using Thin Layer Chromatography (TLC), Ultraviolet (UV) spectroscopy, Mass spectrometry (MS), Fourier-Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Microbial fermentation in the S7 medium yielded 1.60 g/L of taxol, which to the best of our knowledge is the highest taxol production from an endophytic fungus. Findings of the present study suggest that the A. fumigatus is an excellent alternate source for taxol supply, and it may become a highly potent strain on a commercial scale. The involvement of dbat gene in A. fumigatus KU-837249 strain further suggested a way of increasing taxol yield in fungi by medium engineering and recombinant DNA technology in the future.