Excavating the functionally crucial active-site residues of the DXS protein of Bacillus subtilis by exploring its closest homologues.

BACKGROUND: To achieve a high yield of terpenoid-based therapeutics, 1-deoxy-d-xylulose-5-phosphate (DXP) pathway has been significantly exploited for the production of downstream enzymes. The DXP synthase (DXS) enzyme, the initiator of this pathway, is pivotal for the convergence of carbon flux, and is computationally studied well for the industrially utilized generally regarded as safe (GRAS) bacterium Bacillus subtilis to decode its vital regions for aiding the construction of a functionally improved mutant library. RESULTS: For the 546 sequence dataset of DXS sequences, a representative set of 108 sequences is created, and it shows a significant evolutionary divergence across different species clubbed into 37 clades, whereas three clades are observed for the 76 sequence dataset of Bacillus subtilis. The DXS enzyme, sharing a statistically significant homology to transketolase, is shown to be evolutionarily too distant. By the mutual information-based co-evolutionary network and hotspot analysis, the most crucial loci within the active site are deciphered. The 650-residue representative structure displays a complete conservation of 114 loci, and only two co-evolving residues ASP154 and ILE371 are found to be the conserved ones. Lastly, P318D is predicted to be the top-ranked mutation causing the increase in the thermodynamic stability of 6OUW. CONCLUSION: The study excavates the vital functional, phylogenetic, and conserved residues across the active site of the DXS protein, the key rate-limiting controller of the entire pathway. It would aid to computationally understand the evolutionary landscape of this industrially useful enzyme and would allow us to widen its substrate repertoire to increase the enzymatic yield of unnatural molecules for in vivo and in vitro applications.

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.

Iridoid compound 10-O-trans-p-coumaroylcatalpol extends longevity and reduces α synuclein aggregation in Caenorhabditis elegans.

Aging, the major cause of several ailments has led to intense exploration of potential drugs that delay aging and its associated effects. We mined the information on traditional Indian medicines and identified an iridoid, 10-O-trans-p-Coumaroylcatalpol (OCC), a major ingredient of Premna integrifolia Linn. (syn: Premna serratifolia). OCC forms an important constituent of famous herbal formulation 'Dashmula', a ten herb formulation, commonly used for its various medicinal properties. Employing model system C. elegans, the effect of OCC on life span, stress resistance, chemotaxis, the content of reactive oxygen species (ROS) and on the aggregation of alpha synuclein was studied. OCC extended the mean life span of nematodes, increased their tolerance against chemical induced stress, improved the chemotaxis index and reduced the ROS content. Further, the aggregation of Parkinson's disease (PD) associated protein, alpha synuclein (asyn), was decreased when transgenic a-syn expressing worms were raised on OCC mixed diet. We extended the studies further to explore the possible genetic mechanism that mediates the observed effects of OCC. Employing the genetic knockout mutants TK22 [mev-1(kn1)III]; GR1307 [daf-16(mgDf50)I]; VC199 [sir-2.1(ok434)IV] and transgenic GFP expressing strain TJ356 [zls356; DAF-16::GFP], our studies revealed that the effects were mediated by daf-16 and not by sir-2.1 or mev-1. Our results indicate that OCC has the ability to ameliorate a-syn aggregation, reduce oxidative stress and promote longevity in C. elegans via activation of longevity promoting transcription factor DAF-16. Thus, OCC may serve as a lead compound of plant origin for important nutraceutical intervention against aging and age associated PD.

Longevity-promoting effects of 4-hydroxy-E-globularinin in Caenorhabditis elegans.

In modern times, there has been a major increase in the use of plants or herbal constituents for the prevention of age-related disorders. 4-Hydroxy-E-globularinin (4-HEG) is an iridoid and a major component of Premna integrifolia. This investigation represents a breakthrough in geriatrics by showing the longevity-promoting activity of 4-HEG in the animal model Caenorhabditis elegans. 4-HEG (20µM) enhanced the mean life span of worms by over 18.8% under normal culture conditions and also enhanced their survival under oxidative stress. The longevity-promoting activity was associated with reduced reactive oxygen species (ROS) levels and fat accumulation in the worms. Gene-specific mutant studies verified the role of ROS detoxification pathways and simultaneous nuclear translocation of DAF-16 in the 4-HEG-mediated effects. Quantitative real-time PCR estimations and observations of transcriptional reporters indicated that 4-HEG was able to upregulate stress-inducible genes, viz., hsp-16.2 and sod-3. Thus, 4-HEG may serve as a lead compound of plant origin for the development of important nutraceuticals superseding the aging process.