Prospecting endophytic fungal assemblage of Digitalis lanata Ehrh. (foxglove) as a novel source of digoxin: a cardiac glycoside

Endophytes, the chemical synthesizers inside plants, are the microorganisms having mutualistic relationship with the host plant. They can be used by plants for defense in addition to the production of a wide variety of beneficial bioactive secondary metabolites. There are reports that microbial endophytes mimic the bioactive compounds as produced by the plant itself thus making them a promising source of novel compounds. During the present study, endophytes were isolated from the symptomless leaves and stem of the angiosperm, Digitalis lanata (foxglove). Digitalis lanata belongs to the family Plantaginaceae and is an important medicinal plant known for the production of an important glycoside, digoxin having valuable medicinal importance. Glycosides from Digitalis have been reported to be cardiotonic and are widely used in the treatment of various heart conditions namely atrial fibrillation, atrial flutter, heart failure, etc. Endophytic fungi were isolated from Digitalis to screen them for such glycosides as have been found in the plant itself. A total of 35 fungal endophytes were isolated and screened for the production of secondary metabolites. After preliminary analysis by thin layer chromatography for the presence of bioactive compounds, crude extracts of five fungal cultures were selected for HPLC. HPLC chromatograms revealed the production of glycoside digoxin from the five selected endophytic cultures, thus providing a novel, alternative and eco-friendly source for the production of such a pharmaceutically important and valuable drug

Anti-bacterial activity of neoandrographolide derivatives: In silico interaction with the bacterial target

157-164Natural products and their semi synthesized molecules have been used as efficient antibiotics since a long time. The present global health scenario has raised the demand for novel antimicrobial agents and drug targets that are effective against drug resistant pathogens, emerging infections etc. The current study has promoted the antibacterial activity of the glucoside labdane ‘neoandrographolide’, isolated from the methanolic extract of the medicinal plant Andrographis paniculata. Further modification at its glucoside hydroxyl groups to generate ester and acetonide derivatives was done and the antibacterial potential of these compounds was screened against common bacterial pathogens. Among various derivatives, 4,6-O-(4-methoxybenzylidene) neoandrographolide exhibited promising results. In addition, molecular modeling study of the active compound was also explored to identify its probable binding mode on the bacterial target. The present study reported antibacterial activity of neoandrographolide derivatives for first time and also the bioactive molecule, 4,6-O-(4-methoxybenzylidene) neoandrographolide was examined as a potent antibacterial agent against different strains

तमस एक अध्ययन

तमस का चरित्र – चित्रण वर्णनात्मक भी हैं और संकेतिक भी , किन्तु उस वर्णनात्मकता में सूक्ष्मता अथवा व्यंगयात्मकता का अभाव नहीं हैं । सभी चरित्र समसामियक चरिस्थितियों से जुड़े हुए हैं । वे समस्त सांस्कारिक दुर्बलताएँ , धार्मिक उत्तेजनाएँ तथा राजनैतिक स्थार्थ जो ( तमस ) के चरित्रों में विद्यमान हैं । आलोच्य अपन्यास की कहानी अविभाजित पंजाब की कहानी हैं । रावलपिण्ड़ी में हिन्दुओं और मुसलमानों की मिली – जुली आबादी थी । यही कारण हैं कि तमस में हिन्दुओं की भी ह्त्या होती हैं , मुसलमानों का भी रक्त बहता हैं । उपन्यास में तत्कालीन भारत के राजनैतिक , सामाजिक तथा धार्मिक तीनों वातावरणों का चित्रण हुआ हैं । वस्तुतः तमस आग और रक्त की कहनी हैं , किन्तु इसके अति – रिक्त इसमें भ्रष्ट राजनीतिज्ञौं , एक ही देश वासियों को धर्म के आधार अलग करने वाले धर्म गुरूओं , साम्प्रदायिकता की अग्नि में धी ड़ालने वाली अंग्रेज़ शासको का भी उल्लेख हैं

Mechanism of Gene Amplification via Yeast Autonomously Replicating Sequences

The present investigation was aimed at understanding the molecular mechanism of gene amplification. Interplay of fragile sites in promoting gene amplification was also elucidated. The amplification promoting sequences were chosen from the Saccharomyces cerevisiae ARS, 5S rRNA regions of Plantago ovata and P. lagopus, proposed sites of replication pausing at Ste20 gene locus of S. cerevisiae, and the bend DNA sequences within fragile site FRA11A in humans. The gene amplification assays showed that plasmid bearing APS from yeast and human beings led to enhanced protein concentration as compared to the wild type. Both the in silico and in vitro analyses were pointed out at the strong bending potential of these APS. In addition, high mitotic stability and presence of TTTT repeats and SAR amongst these sequences encourage gene amplification. Phylogenetic analysis of S. cerevisiae ARS was also conducted. The combinatorial power of different aspects of APS analyzed in the present investigation was harnessed to reach a consensus about the factors which stimulate gene expression, in presence of these sequences. It was concluded that the mechanism of gene amplification was that AT rich tracts present in fragile sites of yeast serve as binding sites for MAR/SAR and DNA unwinding elements. The DNA protein interactions necessary for ORC activation are facilitated by DNA bending. These specific bindings at ORC promote repeated rounds of DNA replication leading to gene amplification

Origin, Behaviour, and Transmission of B Chromosome with Special Reference to <i>Plantago lagopus</i>

B chromosomes have been reported in many eukaryotic organisms. These chromosomes occur in addition to the standard complement of a species. Bs do not pair with any of the A chromosomes and they have generally been considered to be non-essential and genetically inert. However, due to tremendous advancements in the technologies, the molecular composition of B chromosomes has been determined. The sequencing data has revealed that B chromosomes have originated from A chromosomes and they are rich in repetitive elements. In our laboratory, a novel B chromosome was discovered in Plantago lagopus. Using molecular cytogenetic techniques, the B chromosome was found to be composed of ribosomal DNA sequences. However, further characterization of the chromosome using next generation sequencing (NGS) etc. revealed that the B chromosome is a mosaic of sequences derived from A chromosomes, 5S ribosomal DNA (rDNA), 45S rDNA, and various types of repetitive elements. The transmission of B chromosome through the female sex track did not follow the Mendelian principles. The chromosome was found to have drive due to which it was perpetuating in populations. The present paper attempts to summarize the information on nature, transmission, and origin of B chromosomes, particularly the current status of our knowledge in P. lagopus

B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

Plantago lagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes

Epigenetic Dynamics: Role of Epimarks and Underlying Machinery in Plants Exposed to Abiotic Stress

Abiotic stress induces several changes in plants at physiological and molecular level. Plants have evolved regulatory mechanisms guided towards establishment of stress tolerance in which epigenetic modifications play a pivotal role. We provide examples of gene expression changes that are brought about by conversion of active chromatin to silent heterochromatin and vice versa. Methylation of CG sites and specific modification of histone tail determine whether a particular locus is transcriptionally active or silent. We present a lucid review of epigenetic machinery and epigenetic alterations involving DNA methylation, histone tail modifications, chromatin remodeling, and RNA directed epigenetic changes