Sudeep Tiwari

Withanolide A offers neuroprotection, ameliorates stress resistance and prolongs the life expectancy of Caenorhabditis elegans.

Withanolide A (steroidal lactone) forms the major constituent of the most popular herbal drug in Ayurvedic medicine, Ashwagandha. It has been used since ancient times as an alternative medicine for the treatment of a variety of age related disorders. Here we provide multiple lines of evidence indicating that Withanolide A improves healthspan, delays age-associated physiological changes and also extends the lifespan of Caenorhabditis elegans. We also report several neuroprotective benefits of this natural product, including its anti-amyloidogenic effects, alleviation of α-synuclein aggregation and neuroprotection through modulation of neural mediators like acetylcholine. We observed that Withanolide A mediates lifespan extension and promotes stress resistance via insulin/insulin-like growth factor signaling pathway. Such findings could be helpful to develop a therapeutic medicine from this natural product for the prevention or reversal of age-related ailments and to improve the survival of patients suffering from Alzheimers or Parkinsons disease.

Exploitation of microbes for enhancing bacoside content and reduction of Meloidogyne incognita infestation in Bacopa monnieri L

Despite the vast exploration of rhizospheric microbial wealth for crop yield enhancement, knowledge about the efficacy of microbial agents as biocontrol weapons against root-knot disease is scarce, especially in medicinal plants, viz., Bacopa monnieri. In the present investigation, rhizospheric microbes, viz., Bacillus megaterium, Glomus intraradices, Trichoderma harzianum ThU, and their combinations were evaluated for the management of Meloidogyne incognita (Kofoid and White) Chitwood and bacoside content enhancement in B. monnieri var CIM-Jagriti. A novel validated method Fourier transform near infrared was used for rapid estimation of total bacoside content. A significant reduction (2.75-fold) in root-knot indices was observed in the combined treatment of B. megaterium and T. harzianum ThU in comparison to untreated control plants. The same treatment also showed significant enhancement (1.40-fold) in total bacoside contents (plant active molecule) content using Fourier transform near-infrared (FT-NIR) method that analyses samples rapidly in an hour without solvent usage and provides ample scope for natural product studies.

Enhanced tolerance of Mentha arvensis against Meloidogyne incognita (Kofoid and White) Chitwood through mutualistic endophytes and PGPRs

The use of herbs in pharmaceutical preparation is ever increasing, and the demand for pesticides free material by the concern industries is on the rise. Consequently the need to grow disease-free plants using non-chemical fertilizers and pesticides is the need of the hour. Mentha arvensis cv. kosi is highly infested with Meloidogyne incognita (Kofoid and White) Chitwood, and severe oil yield loss occurs due to this nematode pest. Employing ecofriendly ways of nematode management, the mutualistic endophytes (Trichoderma harzianum strain Thu, Glomus intraradices) and plant growth promoting rhizobacteria (Bacillus megaterium and Pseudomonas fluorescens) were assessed individually and in combination on plant biomass, oil yield of menthol mint (M. arvensis cv. kosi), reproduction potential and population development of root knot nematode, M. incognita under glasshouse conditions. These microbes enhanced the plant biomass and percent oil yield both with and without M. incognita inoculation. Dual application of mutualistic fungal endophytes and Plant Growth Promoting Rhizobacteria (PGPRs) may be a wise option for enhancing the oil yield and tolerance of menthol mint against M. incognita infection.

Bacopa monnieri promotes longevity in Caenorhabditis elegans under stress conditions.

Background: Bacopa monnieri (L.) Pennell, commonly known as Brahmi is an important medicinal plant traditionally used as memory enhancer and antiepileptic agent. Objective: The present study investigated antioxidant and stress resistance potentials of B. monnieri aqueous extract (BMW) using Caenorhabditis elegans animal model system. Materials and Methods: The antioxidant activity of the BMW was measured using in vitro (DPPH, reducing power and total polyphenol content) and in vivo (DCF-DA assay) assays. The antistress potential of BMW (0.1, 0.01, and 0.001 mg/ml) was evaluated through thermal stress (37°C) and oxidative stress (10 mM paraquat) using C. elegans. Quantification of the HSP-16.2 level was done using CL2070 transgenic worms. Results: Present study reveals that BMW possess in vitro and in vivo antioxidant activities. BMW significantly enhanced stress tolerance and increased the mean lifespan of worms during thermal and oxidative stress, although it did not extend lifespan at 20°C and attenuated age dependent decline in physiological behaviors. Moreover, it was shown that BMW was able to up-regulate expression of stress associated gene hsp-16.2, which significantly (P < 0.001) extends the mean lifespan of worms under stress conditions. Conclusion: The study strongly suggests that BMW acts as an antistressor and potent reactive oxygen species scavenger which enhances the survival of the worms in different stress conditions.

Nematode inhibiting organic materials and a strain of Trichoderma harzianum effectively manages Meloidogyne incognita in Withania somnifera fields

The usefulness of Trichoderma harzianum was tested along with farmyard manure, cow urine, neem oil seed cake, and vermicompost separately and in combination to manage Meloidogyne incognita in Withania somnifera. A treatment combination of nematode inhibitory vermicompost and T. harzianum was found to be most effective against M. incognita.

Hexavalent Chromium Induced Histological Alterations in Bacopa monnieri (L.) and Assessment of Genetic Variance

Chromium, a transition metal exists in nature in several oxidation states, the most important being Cr (III) and Cr (VI) species. The two forms display quite different chemical properties as Cr (VI) is highly toxic to most organisms whereas Cr (III) is relatively innocuous. Cr (VI) exposures are responsible for carcinogenic and mutagenic effects in humans also. The present study investigates the changes in cortical and vascular tissues of Bacopa monneiri after short-term exposure to Cr (VI). K 2 Cr 2 O 7 (0.05M) was added to Murashige and Skoog’s (MS) media to which Bacopa explants were introduced and the detrimental effects were studied after 21 days of incubation under different stress conditions. Histological results revealed a time-dependent noxious effect of Cr (VI) on cortical cells. The amount of damage in vascular region was observable but not much defined. Changes included enlargement of the cortical cells and accumulation of chromium within the live tissues. The molecular interpretation of damage due to Cr (VI) was done by PCR amplification of different antioxidant genes and analysing the products on 1% agarose gel. The genes were unable to show expression with cDNA template from explants exposed to Cr (VI) while with cDNA from explants exposed to bacterial isolates and chromium, expression of antioxidant genes was observed. The study will provide glimpses of Cr (VI) induced damage in plant tissue at cellular and genetic levels.

Caenorhabditis elegans as a Toolkit for Studying Mammalian Aging Pathways

During the last few decades the free living soil nematode Caenorhabditis elegans has been highlighted as an important model organism to decipher the role of several conserved signaling pathways in longevity determination. C. elegans is a most effective in vivo model for studying aging due to its cellular complexity and high homology with mammalian biochemical and genetic pathways. Despite its apparent simplicity, lately the nematode C. elegans has been developed into an important model for biomedical research, mostly in the functional characterization of novel drug targets identified using genomics technologies. For many decades, aging was considered to be a passive, entropic process of tissue decline that occurred in a haphazard way. We know now, however, that the aging process, like so many other biological processes, is subject to regulation by classical signaling pathways viz. insulin signaling pathway, mitochondrial pathway etc. Some of these genetic pathways were first of all reported in small, short-lived organisms such as yeast, worms and flies, and a genetic alteration in same pathways turned out to extend lifespan in mammals as well. C. elegans aging mechanism provides a basis to understand how age regulation of a genetic pathway might be conserved between distantly related species. Here we review some aging pathways that are evolutionary conserved and modulates lifespan from worms to mammals viz. Insulin signaling (ILS), Dietary restriction (DR), Mitochondrial respiration and Sirtuin pathway.