Orchid Micropropagation Using Conventional Semi-Solid and Temporary Immersion Systems: A Review.

Orchids, with their astonishingly stunning flowers, dominate the international floricultural market. They are considered prized assets for commercial applications in pharmaceutical and floricultural industries as they possess high therapeutic properties and superior ornamental values. The alarming depletion of orchid resources due to excessive unregulated commercial collection and mass habitat destruction makes orchid conservation measures an extreme priority. Conventional propagation methods cannot produce adequate number of orchids, which would meet the requirement of these ornamental plants for commercial and conservational purposes. In vitro orchid propagation using semi-solid media offers an outstanding prospect of rapidly producing quality plants on a large scale. However, the semi-solid (SS) system has shortcomings with low multiplication rates and high production costs. Orchid micropropagation using a temporary immersion system (TIS) overcomes the limitations of the SS system by reducing production costs and making scaleup and full automation possible for mass plant production. The current review highlights different aspects of in vitro orchid propagation using SS and TIS and their benefits and drawbacks on rapid plant generation.

RAPD, ISSR, and SCoT markers based genetic stability assessment of micropropagated Dendrobium fimbriatum Lindl. var. oculatum Hk. f.- an important endangered orchid.

Dendrobium fimbriatum is an ornamental and medicinal orchid listed in the Red data book of IUCN. Phytohormones' effect on the in vitro regeneration of the orchid was studied using Mitra medium supplemented with different growth regulators. KN produced effective shoot formation when present alone or in combination with IBA or NAA. The shooting was gradually increased when KN concentration was increased from 0.8 to 4.8 mg L-1, but the opposite response was observed with BAP at higher concentration (4.8 mg L-1). IBA either in combination with BAP or KN promoted effective root development and multiplication. Micropropagated orchids grown in the basal medium devoid of any phytohormone showed 100% monomorphism, while low genetic polymorphism of 1.52% (RAPD-Random Amplification of Polymorphic DNA), 1.19% (ISSR-Inter Simple Sequence Repeat) and 3.97% (SCoT-Start Codon Targeted) was exhibited among the regenerants propagated in the hormone enriched medium. UPGMA (Unweighted pair group method using arithmetic averages) dendrograms showed the grouping of mother plant (MP) with the in vitro regenerants. The principal coordinate analysis (PCoA) further confirmed the clustering patterns as determined by the cluster analysis. The study reported for the first time the successful in vitro propagation of Dendrobium fimbriatum and their genetic stability assessment using molecular markers.

Phenylbenzopyrone of Flavonoids as a Potential Scaffold to Prevent SARSCoV-2 Replication by Inhibiting its MPRO Main Protease.

BACKGROUND: In December 2019, an outbreak of a pneumonia-like illness, Corona virus disease 2019 (COVID-19), originating from Wuhan, China, was linked to novel coronavirus, now termed SARS-CoV-2. Unfortunately, no effective drugs or vaccines have been reported yet. The main protease (MPRO) remains the most validated pharmacological target for the design and discovery of inhibitors. OBJECTIVE: The purpose of the study was to find a prospective natural scaffold as an inhibitor for MPRO main protease in SARS-CoV-2 and compare it with repurposed antiviral drugs lopinavir and nelfinavir. METHODS: Natural compound libraries were screened for potential scaffold against MPRO main protease. Molecular dynamics simulation, MM-GBSA and principal component analyses of enzyme- ligand complexes were carried out with the top-ranking hits and compared with the repurposed antiviral drugs lopinavir and nelfinavir. RESULTS: The structure-based virtual screening indicated phenylbenzopyrone of flavonoids as one of the top-ranking scaffolds that have the potential to inhibit the main protease with the Oglycosidic form, performing better than the corresponding aglyconic form. Simulation studies indicated that glycosidic form of flavonoid is a more suitable inhibitor with compounds rutin, procyanidin B6, baicalin and galloylquercetin, demonstrating high affinity and stability, and rutin, emerging as one of the best candidate compounds. Interestingly, rutin was reported to have inhibitory activity against similar protease (3Cprotease of enterovirus A71) and implicated in lung fibrosis. CONCLUSION: The present study on flavonoids, possessing a potential scaffold for inhibiting main protease activity for all betacoronavirus is an attempt to provide new and safe drug leads within a reasonably short period.

Anticancer Applications and Pharmacological Properties of Piperidine and Piperine: A Comprehensive Review on Molecular Mechanisms and Therapeutic Perspectives.

Piperine and piperidine are the two major alkaloids extracted from black pepper (Piper nigrum); piperidine is a heterocyclic moiety that has the molecular formula (CH2)5NH. Over the years, many therapeutic properties including anticancer potential of these two compounds have been observed. Piperine has therapeutic potential against cancers such as breast cancer, ovarian cancer, gastric cancer, gliomal cancer, lung cancer, oral squamous, chronic pancreatitis, prostate cancer, rectal cancer, cervical cancer, and leukemia. Whereas, piperidine acts as a potential clinical agent against cancers, such as breast cancer, prostate cancer, colon cancer, lung cancer, and ovarian cancer, when treated alone or in combination with some novel drugs. Several crucial signalling pathways essential for the establishment of cancers such as STAT-3, NF-κB, PI3k/Aκt, JNK/p38-MAPK, TGF-ß/SMAD, Smac/DIABLO, p-IκB etc., are regulated by these two phytochemicals. Both of these phytochemicals lead to inhibition of cell migration and help in cell cycle arrest to inhibit survivability of cancer cells. The current review highlights the pharmaceutical relevance of both piperine and piperidine against different types of cancers.

Reactive oxygen species scavenging mechanisms associated with polyethylene glycol mediated osmotic stress tolerance in Chinese potato.

Influence of polyethylene glycol (PEG) mediated osmotic stress on reactive oxygen species (ROS) scavenging machinery of Chinese potato (Solenostemon rotundifolius (Poir.) J. K. Morton) was investigated. Five genotypes of Chinese potato were raised in Murashige and Skoog (MS) basal medium containing 6-benzylaminopurine (BAP, 1 mg L-1) along with various concentrations of PEG-6000 mediated stress conditions (0, -0.2 and -0.5 MPa) and evaluated for osmotic stress tolerance in vitro. The medium containing PEG-6000 had a detrimental effect on plantlet growth and development while compared with the control. Accumulation of H2O2 was lower in Sreedhara and Subala and higher in Nidhi under PEG stress, which was evident by in situ detection in leaves. Lipid peroxidation product such as malondialdehyde (MDA) content was increased due to PEG stress which was more in susceptible genotype than that in tolerant ones. An enhanced ROS-scavenging antioxidant enzyme was observed under stress with respect to the control. The enzymes of ascorbate-glutathione cycle showed an important role in scavenging ROS. The imposition of PEG stress also increased the non-enzymatic antioxidants viz., the ascorbate and reduced glutathione content which was prominent in tolerant genotypes in comparison to susceptible. The present study indicated that, Sreedhara and Subala showed more tolerance to osmotic stress with better ROS scavenging machineries which would be the lines of interest for augmenting future breeding strategies in this climate resilient minor tuber crop.

Efficiency of RAPD, ISSR, iPBS, SCoT and phytochemical markers in the genetic relationship study of five native and economical important bamboos of North-East India.

10 primers each of random amplified polymorphic DNA (RAPD), inter-simple sequence repeats (ISSR), inter primer binding site (iPBS) and start codon targeted (SCoT) were used to analyze genetic polymorphism and relationship between 50 genotypes of 5 economical important native bamboos (Bambusa cacharensis, B. mizorameana, Dendrocalamus manipureanus, D. hamiltonii and D. sikkimensis) of North-East India. The 40 different primers generated 111, 115, 116 and 138 polymorphic bands for RAPD, ISSR, iPBS and SCoT markers respectively. The comparative analysis of 4 marker systems based on polymorphic information content (PIC), effective multiplex ratio (EMR) and marker index (MI) values showed SCoT to be more informative with higher discriminating power than the other three markers. The correlation value (r) as determined by the Mantel test ranged from 0.60 (SCoT and RAPD) to 0.83 (iPBS and ISSR) indicating a high positive correlation between the markers. The close correspondence between the genetic matrices of RAPD, ISSR, iPBS and SCoT markers revealed the effectiveness of each marker system in determining the genetic relationship between bamboos. UPGMA (Unweighted Pair Group Arithmetic Mean Method) dendrograms generated from DNA marker analysis demonstrated species-specific clustering of different bamboo genotypes. Except for RAPD, the dendrograms of ISSR, iPBS and SCoT markers also showed a close association of bamboo genotypes based on geographical origin. Principal coordinate analysis (PCoA) revealed the distribution of different bamboo genotypes in accordance with the cluster analysis. The cluster grouping based on phytochemical study not only discriminated the different bamboo species but also illustrated a location-specific grouping of the genotypes. The bamboo clustering pattern derived from phytochemical analysis matched closely with the dendrograms generated by the DNA markers. The present investigation established the possibility of using a combined molecular and phytochemical marker approach to determine the genetic relationship between 5 native bamboos of North-East India with high precision.

Discovery of sulfone-resistant dihydropteroate synthase (DHPS) as a target enzyme for kaempferol, a natural flavanoid.

Kaempferol is a ubiquitous flavonoid, found in various plants having a wide range of known pharmacological activities, including antioxidant, antiinflammatory, anticancer, antiallergic, antidiabetic, neuroprotective, cardioprotective and antimicrobial activities. Nonetheless various evidence suggest that kaempferol is also able to interact with many unknown therapeutic targets modulating signalling pathways, thus providing an opportunity to explore the potential target space of kaempferol. In this study, we have employed various ligand-based approaches to identify the potential targets of kaempferol, followed by validations using modelling and docking studies. Molecular dynamics, free energy calculations, volume and residue contact map analyses were made to delineate the cause of drug-resistance among mutants. We have discovered dihydropteroate synthase (DHPS) as a novel potential therapeutic target for kaempferol. Further studies employing molecular dynamics simulations and binding free energies indicate that kaempferol has potential to inhibit even the sulfone-resistant DHPS mutants, which makes it a very attractive antibiotic agent. The identification of natural-product based kaempferol opens up the door for the design of antibiotics in a quick and high throughput fashion for identifying antibiotic leads.

Hyperoxidation of Peroxiredoxin 6 Induces Alteration from Dimeric to Oligomeric State.

Peroxiredoxins(Prdx), the family of non-selenium glutathione peroxidases, are important antioxidant enzymes that defend our system from the toxic reactive oxygen species (ROS). They are thiol-based peroxidases that utilize self-oxidation of their peroxidatic cysteine (Cp) group to reduce peroxides and peroxidized biomolecules. However, because of its high affinity for hydrogen peroxide this peroxidatic cysteine moiety is extremely susceptible to hyperoxidation, forming peroxidase inactive sulfinic acid (Cys-SO2H) and sulfonic acid (Cys-SO3H) derivatives. With the exception of peroxiredoxin 6 (Prdx6), hyperoxidized sulfinic forms of Prdx can be reversed to restore peroxidase activity by the ATP-dependent enzyme sulfiredoxin. Interestingly, hyperoxidized Prdx6 protein seems to have physiological significance as hyperoxidation has been reported to dramatically upregulate its calcium independent phospholipase A2 activity. Using biochemical studies and molecular dynamic (MD) simulation, we investigated the roles of thermodynamic, structural and internal flexibility of Prdx6 to comprehend the structural alteration of the protein in the oxidized state. We observed the loosening of the hydrophobic core of the enzyme in its secondary and tertiary structures. These changes do not affect the internal dynamics of the protein (as indicated by root-mean-square deviation, RMSD and root mean square fluctuation, RMSF plots). Native-PAGE and dynamic light scattering experiments revealed the formation of higher oligomers of Prdx6 under hyperoxidation. Our study demonstrates that post translational modification (like hyperoxidation) in Prdx6 can result in major alterations of its multimeric status.

Evaluation of genetic relationship between 15 bamboo species of North-East India based on ISSR marker analysis.

The classification of bamboos based on floral morphology and reproductive characters is very hard due to erratic flowering behavior and unusually long reproductive cycle. The application of reliable and effective DNA molecular markers is highly essential to address this problem. In the present investigation, inter-simple sequence repeats (ISSR) markers were employed to study phylogenetic relationship of 15 different bamboos of North-East India. The 10 ISSR primers generated 116 polymorphic loci or scorable bands with average of 11.6 bands per primer. The genetic similarity coefficient ranged from 0.41-0.76 showing high genetic polymorphism among different bamboo species. The phylogenetic tree constructed based on genetic similarity matrix revealed genetic proximity of endemic Bambusamizorameana to other five Dendrocalamus species by clustering into a single group, while Dendrocalamus manipureanus segregated from the cluster indicating its genetic divergent character. Except for Schizotachyum fuchsianum, the three Schizotachyum species viz., S. dullooa, S. pergracile and S. munroi exhibited close genetic affinity by grouping into a single minor clade. Principal coordinates analysis (PCoA) showed distribution of different bamboos species in the plot in accordance to unweighted pair-group method with arithmetic average (UPGMA) cluster analysis. Genetic relationship of 15 different bamboos as revealed from the dendrogram and PCoA analysis reasonably conformed to traditional system of classification though slight disagreement existed. This is the first report on the successful use of ISSR markers in the phylogenetic and genetic variation studies of 15 important bamboos of the region including the endemic bamboo species of B. mizorameana, B. manipureana, D. sikkimensis and D. manipureanus.

ISSR Marker Based Population Genetic Study of Melocanna baccifera (Roxb.) Kurz: A Commercially Important Bamboo of Manipur, North-East India.

Melocanna baccifera (Roxb.) Kurz is an economically important bamboo of North-East India experiencing population depletion in its natural habitats. Genetic variation studies were conducted in 7 populations sampled from 5 districts of Manipur using ISSR molecular markers. The investigation was carried out as a primary step towards developing effective conservation strategies for the protection of bamboo germplasm. ISSR marker analysis showed significant level of genetic variation within the populations as revealed by moderately high average values of Nei's genetic diversity (H 0.1639), Shannon's diversity index (I 0.2563), percentage of polymorphic bands (PPB 59.18), total genetic variation (Ht 0.1961), and genetic diversity within population (Hs 0.1639). The study also divulged a high genetic variation at species level with Shannon's diversity index (I), Nei's genetic diversity (H), and percentage of polymorphic band (PPB%) recorded at 0.3218, 0.1939, and 88.37, respectively. Genetic differentiation among the populations (Gst) was merely 19.42% leaving 80.58% of genetic variation exhibited within the populations. The low genetic diversity between populations was consistent with AMOVA. The low genetic differentiation among populations coupled with existence of significantly high genetic diversity at species level indicated the urgent necessity of preserving and protecting all the existing natural bamboo populations in the region.

Establishment of an efficient in vitro regeneration protocol for rapid and mass propagation of Dendrobium chrysotoxum Lindl. using seed culture.

An efficient in vitro regeneration protocol from seed culture has been established successfully for Dendrobium chrysotoxum, an epiphytic orchid having tremendous ornamental and medicinal values. Seed germination response was encouraging in Mitra (M) medium enriched with different combinations of auxins and cytokinins. Medium supplemented with 0.4% activated charcoal (AC), 2 mg/L 6-benzyl amino purine (BAP), and 2 mg/L indole-3-acetic acid (IAA) produced best seed germination percentage in 2 weeks of culture. Incorporation of higher concentration of kinetin (KN) or BAP in combination with low auxin in medium induced pronounced shooting and leaf formation. Reduction in leaf development was evident when cytokinins exist singly in medium indicating synergistic effect of auxin and cytokinin in leaf induction. Presence of elevated level of indole-3-butyric acid (IBA) or 1-naphthalene acetic acid (NAA) with low cytokinin content in medium generated more in vitro rooting, though IBA was found to be more effective in rooting induction as compared to NAA. The in vitro protocol for asymbiotic seed germination developed from the present investigation can be used for rapid mass propagation of this highly important Dendrobium orchid species.

NeMedPlant: a database of therapeutic applications and chemical constituents of medicinal plants from north-east region of India.

UNLABELLED: The North-East region of India is one of the twelve mega biodiversity region, containing many rare and endangered species. A curated database of medicinal and aromatic plants from the regions called NeMedPlant is developed. The database contains traditional, scientific and medicinal information about plants and their active constituents, obtained from scholarly literature and local sources. The database is cross-linked with major biochemical databases and analytical tools. The integrated database provides resource for investigations into hitherto unexplored medicinal plants and serves to speed up the discovery of natural productsbased drugs. AVAILABILITY: The database is available for free at http://bif.uohyd.ac.in/nemedplant/orhttp://202.41.85.11/nemedplant/