Flavonols affect the interrelated glucosinolate and camalexin biosynthetic pathways in Arabidopsis thaliana

Flavonols are structurally and functionally diverse biomolecules involved in plant biotic and abiotic stress tolerance, pollen development, and inhibition of auxin transport. However, their effects on global gene expression and signaling pathways are unclear. To explore the roles of flavonol metabolites in signaling, we performed comparative transcriptome and targeted metabolite profiling of seedlings from the flavonol-deficient Arabidopsis loss-of-function mutant flavonol synthase1 (fls1) with and without exogenous supplementation of flavonol derivatives (kaempferol, quercetin, and rutin). RNA-seq results indicated that flavonols modulate various biological and metabolic pathways, with significant alterations in camalexin and aliphatic glucosinolate synthesis. Flavonols negatively regulated camalexin biosynthesis but appeared to promote the accumulation of aliphatic glucosinolates via transcription factor-mediated up-regulation of biosynthesis genes. Interestingly, upstream amino acid biosynthesis genes involved in methionine and tryptophan synthesis were altered under flavonol deficiency and exogenous supplementation. Quercetin treatment significantly up-regulated aliphatic glucosinolate biosynthesis genes compared with kaempferol and rutin. In addition, expression and metabolite analysis of the transparent testa7 mutant, which lacks hydroxylated flavonol derivatives, clarified the role of quercetin in the glucosinolate biosynthesis pathway. This study elucidates the molecular mechanisms by which flavonols interfere with signaling pathways, their molecular targets, and the multiple biological activities of flavonols in plants.

Development and analysis of de novo transcriptome assemblies of multiple genotypes of Cymbopogon spp. reveal candidate genes involved in the biosynthesis of aromatic monoterpenes

Despite the high economic value of the monoterpene-rich essential oils from different genotypes of Cymbopogon, the knowledge about the genes and metabolic route(s) involved in the biosynthesis of aromatic monoterpenes in this genus is limited. In the present study, a comprehensive transcriptome analysis of four genotypes of Cymbopogon, displaying diverse quantitative and qualitative profiles of volatile monoterpenes in their essential oils has been carried out. The comparative analysis of the deduced protein sequences corresponding to the transcriptomes of the four genotypes revealed 4609 genotype-specific orthogroups, which might contribute in defining genotype-specific phenotypes. The transcriptome data mining led to the identification of unigenes involved in the isoprenogenesis. The homology searches, combined with the phylogenetic and expression analyses provided information about candidate genes concerning the biosynthesis of monoterpene aldehyde, monoterpene alcohol, and monoterpene esters. In addition, the present study suggests a potential role of geranial reductase like enzyme in the biosynthesis of monoterpene aldehyde in Cymbopogon spp. The detailed analysis of the candidate pathway genes suggested that multiple enzymatic routes might be involved in the biosynthesis of aromatic monoterpenes in the genus Cymbopogon. The present study provides deeper insights into the biosynthesis of monoterpenes, which will be useful for the genetic improvement of these aromatic grasses.

Patient Reported Financial Distress and its Association with Quality of Life and Symptom Burden in Cancer Patients Reporting to a Public Facility in LMIC

PURPOSE/OBJECTIVE(S)

Financial distress (FD) associates with worse quality of life (QoL) and there is paucity of literature from low middle income setting (LMIC). We investigated the prevalence & impact of subjective FD on QoL & symptom burden in advanced cancer patients, reporting to a public facility.

MATERIALS/METHODS

Patients aged ≥18yrs with a diagnosis of cancer within 3months and without prior treatment were accrued. Subjective FD was assessed by EORTC QLQ-C30 and symptoms were assessed by ESAS-R at baseline and 3 months. Patients were classified as experiencing FD if they answered ≥2 on a Likert scale question (1-4 points) asking about FD and dichotomized as Grp 1: No FD and Grp 2: FD. Mean change in score was calculated by subtracting the baseline from the 3-month score for each subscale, minimal important difference (MID) was defined using an anchor of ≥ 10-point compared to baseline for Global Qol and compared between groups. We used Mann Whitney, independent sample t test and Fisher's exact test for determining the association between FD and QoL and symptom burden. A p-value < 0.05 was considered statistically significant.

RESULTS

Of the 100 patients participating in the study, 69% reported subjective financial distress at baseline, 10% had insurance coverage, 27% used distressed financing (borrowing :21%; sold off assets:6%) and debt accumulation was seen in 34% patients. Cost reduction strategies were adopted by 98% patients. Mean Global Health (GH), physical (PF), emotional function (EF) was significantly worse at all time-points in FD patients. Physical (pain, tiredness) and psychological symptom scores (anxiety, depression) were significantly higher at all time points for FD patients. Mean change score for subscales of QoL and symptom burden was not significantly different between groups from baseline to 3 months (Table1).MID for deterioration of Global Qol was Grp 1 vs 2; 21.1% vs 32.7%, p = 0.504.

CONCLUSION

Two-thirds of patients have FD at presentation and report worse quality of life and symptom burden at all time-points. Presence of FD is not associated with significant change in QoL scores or symptom burden over 3 months. Measures are warranted to screen and reduce FD.

Morphological, phytochemical, and transcriptome analyses provide insights into the biosynthesis of monoterpenes in Monarda citriodora

MAIN CONCLUSION

Morphological, phytochemical, and transcriptome analyses revealed candidate genes involved in the biosynthesis of volatile monoterpenes and development of glandular trichomes in Monarda citriodora. Monarda citriodora Cerv. ex Lag. is a valuable aromatic plant due to the presence of monoterpenes as major constituents in its essential oil (EO). Thus, it is of sheer importance to gain knowledge about the site of the biosynthesis of these terpenoid compounds in M. citriodora, as well as the genes involved in their biosynthesis. In this study, we studied different types of trichomes and their relative densities in three different developmental stages of leaves, early stage of leaf development (L1), mid-stage of leaf development (L2), and later stage of leaf development (L3) and the histochemistry of trichomes for the presence of lipid and terpenoid compounds. Further, the phytochemical analysis of this plant through GC-MS indicated a higher content of monoterpenes (thymol, thymoquinone, γ-terpinene, p-cymene, and carvacrol) in the L1 stage with a substantial decrease in the L3 stage of leaf development. This considerable decrease in the content of monoterpenes was attributed to the decrease in the trichome density from L1 to L3. Further, we developed a de novo transcriptome assembly by carrying out RNA sequencing of different plant parts of M. citriodora. The transcriptome data revealed several putative unigenes involved in the biosynthesis of specialized terpenoid compounds, as well as regulatory genes involved in glandular trichome development. The data generated in the present study build a strong foundation for further improvement of M. citriodora, in terms of quantity and quality of its essential oil, through genetic engineering.

Identification of Lipoxygenase gene repertoire of Cannabis sativa and functional characterization of CsLOX13 gene

Lipoxygenase (LOX) enzymes play a pivotal role in the biosynthesis of oxylipins. The phyto-oxilipins have been implicated in diverse aspects of plant biology, from regulating plant growth and development to providing tolerance against biotic and abiotic stresses. C. sativa is renowned for its bioactive secondary metabolites, namely cannabinoids. LOX route is assumed to be involved in the biosynthesis of hexanoic acid, which is one of the precursors of cannabinoids of C. sativa. For obvious reasons, the LOX gene family deserves thorough investigation in the C. sativa. Genome-wide analysis revealed the presence of 21 LOX genes in C. sativa, which can be further grouped into 13-LOX and 9-LOX depending upon their phylogeny as well as the enzyme activity. The promoter regions of the CsLOX genes were predicted to contain cis-acting elements involved in phytohormones responsiveness and stress response. The qRT-PCR-based expression analysis of 21 LOX genes revealed their differential expression in different plant parts (root, stem, young leaf, mature leaf, sugar leaf, and female flower). The majority of CsLOX genes displayed preferential expression in the female flower, which is the primary site for the biosynthesis of cannabinoids. The highest LOX activity and expression level of a jasmonate marker gene were reported in the female flowers among all the plant parts. Several CsLOX genes were found to be upregulated by MeJA treatment. Based on the transient expression in Nicotiana benthamiana and the development of stable Nicotiana tabacum transgenic lines, we demonstrate that CsLOX13 encodes functional lipoxygenase and play an important role in the biosynthesis of oxylipins.

Two homeologous MATE transporter genes, NtMATE21 and NtMATE22, are involved in the modulation of plant growth and flavonol transport in Nicotiana tabacum

The multidrug and toxic compound extrusion (MATE) protein family has been implicated in the transport of a diverse range of molecules, including specialized metabolites. In tobacco (Nicotiana tabacum), only a limited number of MATE transporters have been functionally characterized, and no MATE transporter has been studied in the context of flavonoid transport in this plant species so far. In the present study, we characterize two homeologous tobacco MATE genes, NtMATE21 and NtMATE22, and demonstrate their role in flavonol transport and in plant growth and development. The expression of these two genes was reported to be up-regulated in trichomes as compared with the trichome-free leaf. The transcript levels of NtMATE21 and NtMATE22 were found to be higher in flavonol overproducing tobacco transgenic lines as compared with wild type tobacco. The two transporters were demonstrated to be localized to the plasma membrane. Genetic manipulation of NtMATE21 and NtMATE22 led to altered growth phenotypes and modulated flavonol contents in N. tabacum. The β-glucuronidase and green fluorescent protein fusion transgenic lines of promoter regions suggested that NtMATE21 and NtMATE22 are exclusively expressed in the trichome heads in the leaf tissue and petals. Moreover, in a transient transactivation assay, NtMYB12, a flavonol-specific MYB transcription factor, was found to transactivate the expression of NtMATE21 and NtMATE22 genes. Together, our results strongly suggest the involvement of NtMATE21 and NtMATE22 in flavonol transport as well as in the regulation of plant growth and development.

CstMYB14 links ROS signaling, apocarotenoid metabolism, and stress response in Crocus sativus L

Reactive oxygen species (ROS) behave as signaling molecules and induce biosynthesis of many secondary metabolites, including apocarotenoids, which play critical roles in stress tolerance through radical scavenging. However, the mechanism that regulates ROS responsive apocarotenoid metabolism and subsequent stress response is unknown. In this study, an R2R3-MYB transcription factor (CstMYB14) was identified from Crocus sativus L., which acts as a regulator of apocarotenoid biosynthesis. CstMYB14 expression increases in response to H₂ O₂ in a concentration and time-dependent manner. CstMYB14 localizes to the nucleus and acts as a transcriptional activator. Over-expression of CstMYB14 in Crocus stigmas enhanced apocarotenoid biosynthesis. Yeast-one-hybrid demonstrated binding of CstMYB14 to promoters of two apocarotenoid pathway genes (phytoene synthase and carotenoid cleavage dioxygenase 2). Nicotiana benthamiana plants overexpressing CstMYB14 showed better growth and higher stress tolerance than wild type plants. Higher antioxidant activity in CstMYB14-Ox plants indicated that stress tolerance might be due to ROS scavenging. These results establish a molecular link between ROS signaling, apocarotenoid metabolism and stress tolerance. Further, CstMYB14 is shown to act as a key regulator which modulates ROS responsive biosynthesis of apocarotenoids which in turn impart stress tolerance through ROS scavenging.

Molecular components associated with the regulation of flavonoid biosynthesis

Flavonoids exhibit amazing structural diversity and play different roles in plants. Besides, these compounds have been associated with several health benefits in humans. Several exogenous and endogenous cues, for example, light, temperature, nutrient status, and phytohormones have been reported as modulators of biosynthesis and accumulation of flavonoids. Thus, multiple hormones and stress-related signaling pathways are involved in the regulation of gene expression associated with this pathway. The transcriptional regulators belonging to the MYB and bHLH family transcription factors are well documented as the direct regulators of the structural genes associated with flavonoid biosynthesis. Recent studies also suggest that some of these factors are regulated by molecular components involved in stress and hormone signaling pathways. Adapter proteins for transcriptional activation or repression via recruitment of co-activators and co-repressors, respectively, E2 ubiquitin ligases, miRNA processing complex, and DNA methylation/demethylation factors have been recently discovered in various plants to play key roles in fine-tuning flavonoids synthesis. In the present review, we aim to provide comprehensive information about the role of different factors in the regulation of flavonoid biosynthesis. Besides, we describe the potential upstream regulators involved in the regulation of flavonoid biosynthesis within the context of available information. To sum up, the present review furnishes an updated account of signal transduction pathways modulating the biosynthesis of flavonoids.

Aerosol Loading and Radiation Budget Perturbations in Densely Populated and Highly Polluted Indo-Gangetic Plain by COVID-19: Influences on Cloud Properties and Air Temperature

Aerosols emitted in densely populated and industrialized Indo-Gangetic Plain, one of the most polluted regions in the world, modulate regional climate, monsoon, and Himalayan glacier retreat. Thus, this region is important for understanding aerosol perturbations and their resulting impacts on atmospheric changes during COVID-19 lockdown period, a natural experimental condition created by the pandemic. By analyzing 5 years (2016-2020) data of aerosols and performing a radiative transfer calculation, we found that columnar and near-surface aerosol loadings decreased, leading to reductions in radiative cooling at the surface and top of the atmosphere and atmospheric warming during lockdown period. Further, satellite data analyses showed increases in cloud optical thickness and cloud-particle effective radius and decrease in lower tropospheric air temperature during lockdown period. These results indicate critical influences of COVID-19 lockdown on regional climate and water cycle over Indo-Gangetic Plain, emphasizing need for further studies from modeling perspectives.

Transcriptome-wide identification of squalene epoxidase genes from Glycyrrhiza glabra L.: expression analysis and heterologous expression of GgSQE1 suggest important role in terpenoid biosynthesis

Squalene epoxidase (SQE) is a crucial regulatory enzyme for the biosynthesis of several important classes of compounds including sterols and triterpenoids. The present paper identified and characterised five SQE genes (GgSQE1 to GgSQE5) from Glycyrrhiza glabra through transcriptome data mining and homology-based cloning, for the first time. The phylogenetic analysis implied their functional divergence. The ORF corresponding to one of the five SQEs, namely, GgSQE1, was cloned and studied for its function in a heterologous system, following transient and stable expressions. The transient expression followed by GgSQE1 encoding protein purification suggested approximately 58.0-kDa protein following the predicted molecular mass of the deduced protein. The gene expression profiling based on qRT-PCR indicated its highest expression (6.4-folds) in the 10-month-old roots. Furthermore, ABA (12.4-folds) and GA₃ (2.47) treatments upregulated the expression of GgSQE1 in the shoots after 10 and 12 hours, respectively, which was also reflected in glycyrrhizin accumulation. The inductive effects of ABA and GA₃ over GgSQE1 expression were also confirmed through functional analysis of GgSQE1 promoters using GUS fusion construct. Stable constitutive expression of GgSQE1 in Nicotiana tabacum modulated the sterol contents. The study could pave the way for understanding the metabolic flux regulation concerning biosynthesis of related sterols and triterpenoids.

Glabridin attenuates paracetamol-induced liver injury in mice via CYP2E1-mediated inhibition of oxidative stress

CYP2E1 plays a crucial role in the bio-activation of toxic substances leading to liver damage. In this context, CYP2E1 converts paracetamol (PCM) to N-acetyl-p-benzoquinone imine (NAPQI), which is prone to cause hepatotoxicity. Hence, we aimed to explore the protective effect of glabridin on widely used PCM-induced liver injury model in the present study and, after that, correlated with the role of CYP2E1 toward its efficacy. Glabridin was isolated from Glycyrrhiza glabra and characterized before the investigation in an in-vivo mice model of PCM-induced liver injury. Glabridin after oral treatment at 5-20 mg/kg showed a considerable improvement in serum biochemical parameters (ALT and AST) and oxidative stress markers (MDA, GSH, SOD, and catalase) in comparison to only PCM-treatment. Histopathological examination of the liver depicted that glabridin exhibited substantial protection from PCM-induced liver injury compared to the disease control group. Significant down-regulation of CYP2E1 protein and its mRNA expression levels were observed in the glabridin-treated groups compared to PCM-induced respective elevation of CYP2E1. Moreover, activation of NF-κB was significantly inhibited by glabridin. Therefore, glabridin has the potential to protect PCM-induced liver injury through CYP2E1 inhibition-mediated normalization of oxidative stress. Further research is warranted to establish glabridin as a phytotherapeutics for liver protection for which no effective and safe oral drug is available to date.

Comprehensive genome-wide identification, characterization, and expression profiling of MATE gene family in Nicotiana tabacum

The transporters belonging to the MATE family are involved in the transportation of diverse ligands, including metal ions and small organic molecules, and, therefore, play an important role in plant biology. Our genome-wide analysis led to the identification of 138 MATE genes in N. tabacum, which were grouped into four major phylogenetic clades. The expression of several NtMATE genes was reported to be differential in different tissues, namely young leaf, mature leaf, stem, root, and mature flower. The upstream regions of the NtMATE genes were predicted to contain several cis-acting elements associated with hormonal, developmental, and stress responses. Some of the genes were found to display induced expression following methyl jasmonate treatment. The co-expression analysis revealed 126 candidate transcription factor genes that might be involved in the transcriptional regulation of 21 NtMATE genes. Certain MATE genes (NtMATE81, NtMATE82, NtMATE88, and NtMATE89) were predicted to be targeted by micro RNAs (nta-miR167a, nta-miR167b, nta-miR167c, nta-miR167d and nta-miR167e). The computational analysis of MATE transporters provided insights into the key amino acid residues involved in the binding of the alkaloids. Further, the putative function of some of the NtMATE transporters was also revealed. The present study develops a solid foundation for the functional characterization of MATE transporter genes in N. tabacum.

Control over MoSe2 formation with vacuum-assisted selenization of one-step electrodeposited Cu-In-Ga-Se precursor layers

Cu(In,Ga)Se₂ (CIGS) absorbers are prepared by direct current electrodeposition process followed by selenization of precursors. Selenization of electrodeposited layers is performed in a tubular furnace at 550 °C in elemental selenium atmosphere using Ar as carrier gas. The effect of evacuation of tube prior to the selenization on the formation of CIGS absorbers is studied. Characterization of CIGS absorbers reveals that the samples selenized without prior evacuation found to have excess MoSe₂ formation at the CIGS/Mo interface leading to bulk cracks in underlying Mo back contact compared to their counterparts. Although the fabricated solar cells using the absorbers, prepared with and without evacuation, are observed to be photoactive, the cells from vacuum-based selenization showed improvement in performance compared to the cells from non-vacuum selenization. The process is further being improved to enhance the efficiency, which can pave way towards environmentally friendly low-cost solar cells.

Membrane transporters: the key drivers of transport of secondary metabolites in plants

This review summarizes the recent updates in the area of transporters of plant secondary metabolites, including their applied aspects in metabolic engineering of economically important secondary metabolites. Plants have evolved biosynthetic pathways to produce structurally diverse secondary metabolites, which serve distinct functions, including defense against pathogens and herbivory, thereby playing a pivotal role in plant ecological interactions. These compounds often display interesting bioactivities and, therefore, have been used as repositories of natural drugs and phytoceuticals for humans. At an elevated level, plant secondary metabolites could be cytotoxic to the plant cell itself; therefore, plants have developed sophisticated mechanisms to sequester these compounds to prevent cytotoxicity. Many of these valuable natural compounds and their precursors are biosynthesized and accumulated at diverse subcellular locations, and few are even transported to sink organs via long-distance transport, implying the involvement of compartmentalization via intra- and intercellular transport mechanisms. The transporter proteins belonging to different families of transporters, especially ATP binding cassette (ABC) and multidrug and toxic compound extrusion (MATE) have been implicated in membrane-mediated transport of certain plant secondary metabolites. Despite increasing reports on the characterization of transporter proteins and their genes, our knowledge about the transporters of several medicinally and economically important plant secondary metabolites is still enigmatic. A comprehensive understanding of the molecular mechanisms underlying the whole route of secondary metabolite transportome, in addition to the biosynthetic pathways, will aid in systematic and targeted metabolic engineering of high-value secondary metabolites. The present review embodies a comprehensive update on the progress made in the elucidation of transporters of secondary metabolites in view of basic and applied aspects of their transport mechanism.

Characterization and overexpression of sterol Δ22-desaturase, a key enzyme modulates the biosyntheses of stigmasterol and withanolides in Withania somnifera (L.) Dunal

Withanolides constitute an extensive and vital class of metabolites displaying wide array of structural and therapeutic properties with unique side-chain modifications. These show diversified scaffolds and are promising pharmaceutical molecules with well documented anti-inflammatory and anti-cancer properties. Sterols are dynamic class of compounds and essential molecules having structural and functional significance. These contribute to the synthesis of withanolides by providing structural precursors. In this context, we have characterized sterol Δ22-desaturase from Withania somnifera and also functionally validating it by confirming its desaturase nature in conjunction with quantitative real-time expression profiling and metabolite evaluation. Further, transgenic hairy roots of W. somnifera displayed a higher accumulation of stigmasterol and withanolides. The increase in chemical constituents was concomitant with an increased gene copy number predicted via Southern blotting. Additionally, transgenic lines of tobacco over-expressing WsCYP710A11 displayed a substantial increase in its expression, corroborating well with enhanced stigmasterol content. Characterization of CYP710A11 from W. somnifera and its homologous transgenic expression has demonstrated its role in the regulation of withanolides biosynthesis. It also exhibited a differential transcriptional profile in response to exogenous elicitations. These empirical findings suggest the crucial role of CYP710A11 in stigmasterol biosynthesis. This in turn has implications for the overproduction of withanolides via pathway channelling.

Comprehensive transcriptome analysis provides insights into metabolic and gene regulatory networks in trichomes of Nicotiana tabacum

KEY MESSAGE

Comprehensive transcriptome analysis suggested that the primary metabolism is modulated to augment the supply of substrates towards secondary metabolism operating in the glandular trichomes of Nicotiana tabacum. The comparative gene expression and co-expression network analysis revealed that certain members of transcription factor genes belonging to the MYB, HD-ZIP, ERF, TCP, SRS, WRKY and DOF families may be involved in the regulation of metabolism and/other aspects in the glandular trichomes of N. tabacum The glandular trichomes of Nicotiana tabacum are highly productive in terms of secondary metabolites and therefore have been projected to be used as a prognostic platform for metabolic engineering of valuable natural products. For obvious reasons, detailed studies pertaining to the metabolic and gene regulatory networks operating in the glandular trichomes of N. tabacum are of pivotal significance to be undertaken. We have carried out next-generation sequencing of glandular trichomes of N. tabcaum and investigated differential gene expression among different tissues, including trichome-free leaves. We identified a total of 37,269 and 37,371 genes, expressing in trichome free leaf and glandular trichomes, respectively, at a cutoff of FPKM ≥ 1. The analysis revealed that different pathways involved with the primary metabolism are modulated in glandular trichomes of N. tabacum, providing a plausible explanation for the enhanced biosynthesis of secondary metabolism in the glandular trichomes. Further, comparative gene expression analysis revealed several genes, which display preferential expression in the glandular trichomes and thereby seem to be potential candidate genes for future studies in connection to the discovery of novel trichome specific promoters. The present study also led to the comprehensive identification of 1750 transcription factor genes expressing at a cutoff of FPKM ≥ 1 in the glandular trichomes of N. tabacum. The clustering and co-expression analysis suggested that transcription factor genes belonging to HD-ZIP, ERF, WRKY, MYB, TCP, SRS and DOF families may be the major players in the regulation of gene expression in the glandular trichomes of N. tabacum. To the best of our knowledge, the present work is the first effort towards detailed identification of genes, especially regulatory genes expressing in the glandular trichomes of N. tabacum. The data resource and the empirical findings from present work in all probability must, therefore, provide a reference and background context for future work aiming at deciphering molecular mechanism of regulation of secondary metabolism and gene expression in the glandular trichomes of N. tabacum.

Molecular characterization and overexpression analyses of secologanin synthase to understand the regulation of camptothecin biosynthesis in Nothapodytes nimmoniana (Graham.) Mabb

Camptothecin is a high-value anti-cancerous compound produced in many taxonomically unrelated species. Its biosynthesis involves a complex network of pathways and a diverse array of intermediates. Here, we report the functional characterization and regulation of secologanin synthase (NnCYP72A1), a cytochrome P450 involved in camptothecin biosynthesis from Nothapodytes nimmoniana. It comprises an open reading frame of 1566 bp in length. Heterologous expression in Saccharomyces cerevisiae and in vitro enzymatic assays using loganin as substrate confirmed the formation of secologanin. In planta transient overexpression analysis of NnCYP72A1 resulted in 4.21- and 2.73-fold increase in transcript levels of NnCYP72A1 on days 3 and 6 respectively. Phytochemical analysis of transformed tissues revealed ~ 1.13-1.43- and 2.02-2.86-fold increase in secologanin and CPT accumulation, respectively. Furthermore, promoter analysis of NnCYP72A1 resulted in the identification of several potential cis-regulatory elements corresponding to different stress-related components. Methyl jasmonate, salicylic acid, and wounding treatments resulted in considerable modulation of mRNA transcripts of NnCYP72A1 gene. Chemical analysis of elicitor-treated samples showed a significant increase in CPT content which was concordant with the mRNA transcript levels. Overall, the functional characterization and overexpression of NnCYP72A1 may plausibly enhance the pathway intermediates and serve as prognostic tool for enhancing CPT accumulation.

Metabolic and transcriptional analyses in response to potent inhibitors establish MEP pathway as major route for camptothecin biosynthesis in Nothapodytes nimmoniana (Graham) Mabb

BACKGROUND

Nothapodytes nimmoniana, a plant of pivotal medicinal significance is a source of potent anticancer monoterpene indole alkaloid (MIA) camptothecin (CPT). This compound owes its potency due to topoisomerase-I inhibitory activity. However, biosynthetic and regulatory aspects of CPT biosynthesis so far remain elusive. Production of CPT is also constrained due to unavailability of suitable in vitro experimental system. Contextually, there are two routes for the biosynthesis of MIAs: the mevalonate (MVA) pathway operating in cytosol and the methylerythritol phosphate (MEP) pathway in the plastids. Determination of relative precursor flux through either of these pathways may provide a new vista for manipulating the enhanced CPT production.

RESULTS

In present study, specific enzyme inhibitors of MVA (lovastatin) and MEP pathways (fosmidomycin) were used to perturb the metabolic flux in N. nimmoniana. Interaction of both these pathways was investigated at transcriptional level by using qRT-PCR and at metabolite level by evaluating secologanin, tryptamine and CPT contents. In fosmidomycin treated plants, highly significant reduction was observed in both secologanin and CPT accumulation in the range 40-57% and 64-71.5% respectively, while 4.61-7.69% increase was observed in tryptamine content as compared to control. Lovastatin treatment showed reduction in CPT (7-11%) and secologanin (7.5%) accumulation while tryptamine registered slight increase (3.84%) in comparison to control. These inhibitor mediated changes were reflected at transcriptional level via altering expression levels of deoxy-xylulose-5-phosphate reductoisomerase (DXR) and hydroxymethylglutaryl-CoA reductase (HMG). Further, mRNA expression of four more genes downstream to DXR and HMG of MEP and MVA pathways respectively were also investigated. Expression analysis also included secologanin synthase (SLS) and strictosidine synthase (STR) of seco-iridoid pathway. Present investigation also entailed development of an efficient in vitro multiplication system as a precursor to pathway flux studies. Further, a robust Agrobacterium-mediated transformed hairy root protocol was also developed for its amenability for up-scaling as a future prospect.

CONCLUSIONS

Metabolic and transcriptional changes reveal differential efficacy of cytosolic and plastidial inhibitors in context to pathway flux perturbations on seco-iridoid end-product camptothecin. MEP pathway plausibly is the major precursor contributor towards CPT production. These empirical findings allude towards developing suitable biotechnological interventions for enhanced CPT production.

Jasmonate responsive transcription factor WsMYC2 regulates the biosynthesis of triterpenoid withanolides and phytosterol via key pathway genes in Withania somnifera (L.) Dunal

Functional characterization of WsMYC2 via artificial microRNA mediated silencing and transient over-expression displayed significant regulatory role vis-à-vis withanolides and stigmasterol biosyntheses in Withania somnifera. Further, metabolic intensification corroborated well with higher expression levels of putative pathway genes. Additionally, copious expression of WsMYC2 in response to exogenous elicitors resulted in enhanced withanolides production. Withania somnifera, a high value multipurpose medicinal plant, is a rich reservoir of structurally diverse and biologically active triterpenoids known as withanolides. W. somnifera has been extensively pursued vis-à-vis pharmacological and chemical studies. Nonetheless, there exists fragmentary knowledge regarding the metabolic pathway and the regulatory aspects of withanolides biosynthesis. Against this backdrop, a jasmonate-responsive MYC2 transcription factor was identified and functionally characterized from W. somnifera. In planta transient over-expression of WsMYC2 showed significant enhancement of mRNA transcript levels which corroborated well with the enhanced content of withanolides and stigmasterol. Further, a comparative analysis of expression levels of some of the genes of triterpenoid pathway viz. WsCAS, WsCYP85A, WsCYP90B and WsCYP710A in corroboration with the over-expression and silencing of WsMYC2 suggested its positive influence on their regulation. These corroboratory approaches suggest that WsMYC2 has cascading effect on over-expression of multiple pathway genes leading to the increased triterpenoid biosynthesis in infiltered plants. Further, the functional validation of WsMYC2 was carried out by artificial micro-RNA mediated silencing. It resulted in significant reduction of withanolides and stigmasterol levels, indicative of crucial role of WsMYC2 in the regulation of their biosyntheses. Taken together, these non-complementary approaches provided unambiguous understanding of the regulatory role of WsMYC2 in context to withanolides and stigmasterol biosyntheses. Furthermore, the upstream promoter of WsMYC2 presented several cis-regulatory elements primarily related to phytohormone responsiveness. WsMYC2 displayed inducible nature in response to MeJA. It had substantial influence on the higher expression of WsMYC2 which was in consonance with enhanced accumulation of withanolides.

Relationship between body mass index and percentage of body fat, estimated by bio-electrical impedance among adult females in a rural community of North India: A cross-sectional study

Introduction:

Body adiposity measured by percentage of body fat (BF%) is found to be better predictor of cardiovascular morbidity and mortality than body mass index (BMI). Limited information exists showing relationship between BMI and BF% in North Indian population.

Objectives:

To study the relationship between BMI and BF% among North Indian adult females across various age strata and level of BMI.

Materials and Methods:

This was a cross-sectional study conducted at Ballabgarh Health and Demographic Surveillance Site (HDSS) among randomly selected females. BMI using standard techniques and BF% using bioelectrical impedance analysis was estimated. Linear regression was performed using general linear model with BF% as dependent variable and BMI as main independent variable.

Results:

Mean (±2 SD) age of participants was 41.3 ± 15.7 years. Mean BMI (±SD) was 23.3 (±4.6) kg/m², whereas mean fat mass (±2 SD) and BF% (±95% CI) was 19.2 (±7.9) kg and 33.6 (±6.9) %. BMI and BF% were highly correlated among obese (r = 0.77), whereas least correlated (r = 0.32) in underweight females. Across age strata, correlation between BMI and BF% was maximum in 18–35 years age group (r = 0.95), whereas least in females ≥56 years (r = 0.67). Age and BMI together predicted 73% of variability in BF% in hierarchical linear regression model.

Conclusions:

In this population, we have found strong correlation between BMI and BF% particularly at higher level of BMI and in younger females. There is need to conduct more robust prospective longitudinal studies to assess BF%, which is a better predictor of cardiovascular morbidity and mortality.

Gene Silencing and Over-Expression Studies in Concurrence With Promoter Specific Elicitations Reveal the Central Role of WsCYP85A69 in Biosynthesis of Triterpenoids in Withania somnifera (L.) Dunal

Withania somnifera (Ashwagandha) synthesizes a wide spectrum of triterpenoids that are produced via an intricate isoprenoid pathway whose biosynthetic and regulatory mechanism remains elusive. Their pharmacological examination position them as potent bioactive molecules, hence demanding their copious production. Previous investigations have revealed that P450 monooxygenases are pivotal enzymes involved in the biosynthetic machinery of various metabolites and assist in decorating their core skeletal structures. The present study entails the isolation and functional characterization of castasterone synthase (CYP85A69) from W. somnifera. The full length WsCYP85A69, having an open reading frame of 1413 bp, encodes 470 amino acid residues. Further, in vitro conversion of 6-deoxocastasterone into castasterone validated its oxidative functionality. Product formation was confirmed using LC-PDA-MS with a m/z value of 506 [M+ACN]⁺. In planta transient over-expression of WsCYP85A69 significantly enhanced castasterone, stigmasterol and withanolides (WS-I, WS-II, WS-III). Artificial micro-RNA mediated silencing of WsCYP85A69 resulted in the reduced accumulation of castasterone, stigmasterol and withanolides (WS-I, WS-II, WS-III). Altogether, these non-complementary approaches plausibly suggest a key role of WsCYP85A69 in the biosynthesis of castasterone and the accumulation of withanolides and stigmasterol. Furthermore, a promoter analysis of WsCYP85A69 resulted in the identification of several potential cis-regulatory elements. Elicitations, given on the basis of identified cis-regulatory elements, demonstrated methyl jasmonate as an effective inducer of WsCYP85A69. Overall, these empirical findings suggest that functional characterization of WsCYP85A69 may conceivably be helpful to unravel the mechanism of brassinosteroids biosynthesis and could also pave the way for targeted metabolic engineering.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

De novo transcriptome analyses reveals putative pathway genes involved in biosynthesis and regulation of camptothecin in Nothapodytes nimmoniana (Graham) Mabb

Comprehensive transcriptome analysis of leaf and root tissues of Nothapodytes nimmoniana unravels several putative pathway genes, transcription factors and CYPs related to camptothecin (CPT) biosynthesis. Additionally, post-transcriptional suppression by artificial microRNA (aMIR) of NnCYP76B6 (geraniol 10-hydroxylase) suggests its role in CPT biosynthesis. Tissue-specific LC-MS/MS analysis revealed the presence of secologanin as the central intermediate of MIA pathway in N. nimmoniana. Nothapodytes nimmoniana is a rich source of potent anticancer drug camptothecin (CPT) whose biosynthetic pathway is unresolved due to the lack of genomic and transcriptomic information. Present investigation entails deep transcriptome analysis of N. nimmoniana which led to identification of putative pathway genes and regulatory components involved in CPT biosynthesis. Using Illumina HiSeq 2500 sequencing platform a total of 31,172,889 (6.23 Gb) and 31,218,626 (6.24 Gb) raw reads were generated from leaf and root wood, respectively. These were assembled de novo into 138,183 unique contigs. Additionally, 16 cytochrome P450 transcripts related to secondary metabolism were also identified. Further, transcriptome data pool presented 1683 putative transcription factors of which transcripts corresponding to WRKY TFs were the most abundant (14.14%). A total of 2741 transcripts were differentially expressed out of which 478 contigs showed downregulation in root wood and 2263 contigs were up-regulated. Further, comparative analyses of 17 genes involved in CPT biosynthetic pathway were validated by qRT-PCR. On basis of intermediates, two distinct seco-iridoid pathways are involved in the biosynthesis of monoterpene indole alkaloids either through multiple isomers of strictosidinic acid or strictosidine. Tissue-specific LC-MS/MS analysis revealed the presence of secologanin as the central intermediate of MIA pathway in N. nimmoniana. Geraniol-10 hydroxylase (NnCYP76B6) an important enzyme in CPT biosynthesis which specifically shunts geraniol into the secologanin pathway was also cloned from the trancriptome resource. In planta transient expression of NnCYP76B6 showed a significant enhancement in mRNA transcript levels coincident with enhanced CPT accumulation. Further, artificial microRNA (aMIR) mediated downregulation of NnCYP76B6 resulted in reduction of mRNA transcript levels as well as CPT content in comparison to control. These empirical results suggest a plausible regulatory role for NnCYP76B6 in CPT biosynthesis and also establish a valuable repository for deciphering various structural, rate limiting and regulatory genes of CPT biosynthetic pathway.

T cell suppression in the bone marrow of visceral leishmaniasis patients: impact of parasite load

Visceral leishmaniasis (VL) is a disseminated and lethal disease of reticulo-endothelial system caused by protozoan parasites Leishmania donovani and L. infantum, which are known to induce host T cell suppression. To understand the impact of parasite load on T cell function, the present was focused on parasite load with T cell function in bone marrow of 26 VL patients. We observed significant enrichment of forkhead box protein 3 (FoxP3)⁺ (P = 0·0003) and interleukin (IL)-10⁺ FoxP3⁺ regulatory T cells (T_reg ) (P = 0·004) in the bone marrow (BM) of patients with high parasite load (HPL) compared with low parasite load (LPL). Concordantly, T effector cells producing interferon (IFN)-γ (P = 0·005) and IL-17A (P = 0·002) were reduced in the BM of HPL. Blocking of T_reg -cell derived suppressive cytokines [(IL-10 and transforming growth factor (TGF)-β] rescued the effector T cells and their functions. However, it was observed that TGF-β levels were dominant, favouring T_reg cell differentiation. Furthermore, the low ratio of IL-6/TGF-β favours the suppressive milieu in HPL patients. Here we show the change in levels of various cytokines with the parasitic load during active VL, which could be helpful in devising newer immunotherapeutic strategies against this disease.

Influence of alcohol on condom use pattern during non-spousal sexual encounter in male migrant workers in north India

CONTEXT

Migrant workers constitute an important risk group for Human Immunodeficiency Virus/Acquired Immuno-Deficiency Syndrome transmission in India. Alcohol consumption before sexual intercourse has been postulated to influence condom use practices. This study aimed to assess this association with regard to non-spousal sexual encounters among male migrant workers in northern India.

MATERIALS AND METHODS

A cross-sectional facility-based survey was conducted in 2011. Male migrant workers aged ≥18 years, who were born outside Haryana, who had moved to the current location after 15 years of age,had worked in the current factory for at least 1 year, who were willing to participate and were able to give written, informed consent were included in the study. A consecutive sampling was performed. Descriptive, bivariate and multiple logistic regression analyses were carried out.

RESULTS

A total of 162 participants reported having experienced non-spousal sexual encounters in the last 1 year. The proportion of men who reported not having used a condom at their last non-spousal sexual encounter was 59.3%, and 78.4% of the men reported having consumed alcohol in the last 1 year. About 48.1% of men reported having consumed alcohol before their last non-spousal sexual encounter. Men who consumed alcohol were three times more likely to not use a condom at their last non-spousal sexual encounter (OR = 3.1, 95% CI: 1.5-6.4). This association persisted even after adjusting for relevant confounders.

CONCLUSION

Alcohol consumption had a negative influence on condom use during non-spousal sexual encounter among male migrant workers. An integrated approach to promote condom use and reduce alcohol consumption among migrant men needs to be undertaken through targeted intervention strategies.

Immunostimulatory potential and proteome profiling of Leishmania donovani soluble exogenous antigens

Isolation of the soluble exogenous antigens (SEAgs), its immune response study and proteome profiling is an essential prerequisite for understanding the molecular pathogenesis of Leishmania donovani. The immunostimulatory potential of L. donovani SEAgs, purified from culture of L. donovani clinical isolate, was evaluated for their ability to induce cellular responses in treated/cured hamsters. SEAgs induced significant proliferative responses in lymphocytes (SI 5.6 ± 2.3; P < 0.01) isolated from cured hamster. In addition, significant NO production in response to SEAgs was also noticed in macrophages of hamsters, mouse and human cell lines (J774A-1 and THP1). Western blot analyses with antibodies against proteophosphoglycan (PPG; surface-expressed and secreted molecule) of L. donovani revealed that PPG molecules are also present in L. donovani SEAgs. Mass spectrometry (MS)-based proteome analysis of 12 protein bands of SEAgs through MALDI-TOF/TOF endorsed the identification of some Th1-stimulatory immunogenic proteins. These immunogenic proteins may offer increased hope for the discovery of new promising vaccine candidates against visceral leishmaniasis (VL). The overall results suggest that immunostimulatory molecules are present in the SEAgs, which may be further exploited, for developing a subunit vaccine against VL a fatal human disease.

Genome-Wide Identification and Expression Analysis of Homeodomain Leucine Zipper Subfamily IV (HDZ IV) Gene Family from Musa accuminata

The homeodomain zipper family (HD-ZIP) of transcription factors is present only in plants and plays important role in the regulation of plant-specific processes. The subfamily IV of HDZ transcription factors (HD-ZIP IV) has primarily been implicated in the regulation of epidermal structure development. Though this gene family is present in all lineages of land plants, members of this gene family have not been identified in banana, which is one of the major staple fruit crops. In the present work, we identified 21 HDZIV encoding genes in banana by the computational analysis of banana genome resource. Our analysis suggested that these genes putatively encode proteins having all the characteristic domains of HDZIV transcription factors. The phylogenetic analysis of the banana HDZIV family genes further confirmed that after separation from a common ancestor, the banana, and poales lineages might have followed distinct evolutionary paths. Further, we conclude that segmental duplication played a major role in the evolution of banana HDZIV encoding genes. All the identified banana HDZIV genes expresses in different banana tissue, however at varying levels. The transcript levels of some of the banana HDZIV genes were also detected in banana fruit pulp, suggesting their putative role in fruit attributes. A large number of genes of this family showed modulated expression under drought and salinity stress. Taken together, the present work lays a foundation for elucidation of functional aspects of the banana HDZIV encoding genes and for their possible use in the banana improvement programs.

Constitutive expression of Arabidopsis MYB transcription factor, AtMYB11, in tobacco modulates flavonoid biosynthesis in favor of flavonol accumulation

KEY MESSAGE

Heterologous expression of AtMYB11 , a flavonol-specific transcription factor from Arabidopsis , in tobacco modulates flavonoid biosynthesis, however, with a lower efficiency as compared to its paralogs AtMYB12 and AtMYB111. Transcriptional regulation is the most important means for controlling flavonoid biosynthesis under temporal and spatial cues. In Arabidopsis, three functionally redundant MYB transcription factors (AtMYB11, AtMYB111 and AtMYB12) have been characterized as flavonol-specific regulators which positively modulate expression of biosynthetic genes involved in flavonol biosynthesis. Based on expression of AtMYB111 and AtMYB12 in heterologous systems, studies suggest that these transcription factors can be used to develop plants with enhanced flavonol biosynthesis. The potential of AtMYB11 to activate flavonol biosynthesis in a heterologous system has not yet been studied. In this study, the regulatory potential of AtMYB11 has been studied in Nicotiana tabacum by developing transgenic plants constitutively expressing AtMYB11. Our analysis using leaf and petal tissues of the transgenic plants indicates that AtMYB11 enhances flavonol and chlorogenic acid (CGA) biosynthesis in tobacco through up-regulation of the biosynthetic genes. Activation of flavonol biosynthesis in tobacco by AtMYB11 is not as pronounced as with AtMYB12 or AtMYB111. Taken together, these results reveal a differential regulatory mechanism in plants for modulating flavonol biosynthesis. This study demonstrated that AtMYB11 can be strategically used for enhancing the health beneficial flavonols in species other than Arabidopsis.

AtMYB12 expression in tomato leads to large scale differential modulation in transcriptome and flavonoid content in leaf and fruit tissues

Plants synthesize secondary metabolites, including flavonoids, which play important role during various stresses for their survival. These metabolites are also considered as health-protective components in functional foods. Flavonols, one of the important groups of flavonoids, apart from performing several roles in plants have been recognized as potent phytoceuticals for human health. Tomato fruits are deficient in this group of flavonoids and have been an important target for enhancing the accumulation of flavonols through genetic manipulations. In the present study, AtMYB12 transcription factor of the Arabidopsis has been expressed under constitutive promoter in tomato. Transgenic tomato lines exhibited enhanced accumulation of flavonols and chlorogenic acid (CGA) in leaf and fruit accompanied with elevated expression of phenylpropanoid pathway genes involved in flavonol biosynthesis. In addition, global gene expression analysis in leaf and fruit suggested that AtMYB12 modulates number of molecular processes including aromatic amino acid biosynthesis, phytohormone signaling and stress responses. Besides this, a differential modulation of the genes in fruits and leaves is reported in this study. Taken together, results demonstrate that modulation of primary carbon metabolism and other pathways by AtMYB12 in tomato may lead to sufficient substrate supply for enhanced content of phenolics in general and flavonols in particular.

Comparative Transcriptional Profiling of Contrasting Rice Genotypes Shows Expression Differences during Arsenic Stress

Accumulation of arsenic (As) in rice (Oryza sativa L.) grain is a serious concern worldwide. Long-term exposure to As affects nutritional status in rice grain and is associated with higher rates of skin, bladder, and lung cancers, and heart disease. Genotypic variations in rice for As accumulation or tolerance are prevalent and are regulated by genetic and environmental factors. To understand molecular networks involved in As accumulation, genome-wide expression analysis was performed in roots of low- and high-As accumulating rice genotypes (LARGs and HARGs). Six rice genotypes with contrasting As accumulation potential and tolerance were used in this study. Genome-wide expression analysis suggested their differential response against As stress. This study suggests up- and downregulation of a number of unique genes involved in various pathways and biological processes in response to As stress in rice genotypes. A comparison of gene expression profiles, principal component analysis, and K-means clustering suggests that an independent pathway is operating during As stress tolerance or accumulation in contrasting genotypes. It was also observed that the differential behavior of aus genotype, Nayanmoni, from other LARGs might be due to its different genetic background. Cis-motif profiling of As-induced coexpressed genes in diverse rice genotypes led to the identification of unique cis-motifs present in differentially expressed genes. This study suggests that the genetic mechanism regulating the differential As accumulation in different genotypes may not be dependent on gene expression at the transcriptional level. However, many genes identified in this study can be analyzed and used for marker-trait associations related to As accumulation in diverse genotypes around the world.

Band offset at TiO2/MDMO PPV and TiO2/PEDOT PSS interfaces studied using photoelectron spectroscopy

We report band alignment and band offset studies across the interfaces of hetero-structures of TiO₂ with MDMO PPV and PEDOT PSS using photoelectron spectroscopy.

Coating doxorubicin-loaded nanocapsules with alginate enhances therapeutic efficacy against Leishmania in hamsters by inducing Th1-type immune responses

BACKGROUND AND PURPOSE

The aim of the present study was to evaluate the immunomodulatory and chemotherapeutic potential of alginate-(SA) coated nanocapsule (NCs) loaded with doxorubicin (SA-NCs-DOX) against visceral leishmaniasis in comparison with nano-emulsions containing doxorubicin (NE-DOX).

EXPERIMENTAL APPROACH

NE-DOX was prepared using low-energy emulsification methods. Stepwise addition of protamine sulphate and SA in a layer-by-layer manner was used to form SA-NCs-DOX. SA-NCs-DOX, NE-DOX and Free DOX were compared for their cytotoxicity against Leishmania donovani-infected macrophages in vitro and generation of T-cell responses in infected hamsters in vivo.

KEY RESULTS

Size and ζ potential of the NE-DOX and SA-NCs-DOX formulations were 310 ± 2.1 nm and (-)32.6 ± 2.1 mV, 342 ± 4.1 nm and (-)29.3 ± 1.2 mV respectively. SA-NCs-DOX was better (1.5 times) taken up by J774A.1 macrophages compared with NE-DOX. SA-NCs -DOX showed greater efficacy than NE-DOX against intramacrophagic amastigotes. SA-NCs-DOX treatment exhibited enhanced apoptotic efficiency than NE-DOX and free DOX as evident by cell cycle analysis, decrease in mitochondrial membrane potential, ROS and NO production. T-cell responses, when assessed through lymphoproliferative responses, NO production along with enhanced levels of iNOS, TNF-α, IFN-γ and IL-12 were found to be up-regulated after SA-NCs-DOX, compared with responses to NE-DOX in vivo. Parasitic burden was decreased in Leishmania-infected hamsters treated with SA-NCs-DOX, compared with NE-DOX.

CONCLUSIONS AND IMPLICATIONS

Our results provide insights into the development of an alternative approach to improved management of leishmaniasis through a combination of chemotherapy with stimulation of the innate immune system.

Expression of Arabidopsis MYB transcription factor, AtMYB111, in tobacco requires light to modulate flavonol content

Flavonoids, due to their pharmacological attributes, have recently become target molecules for metabolic engineering in commonly consumed food crops. Strategies including expression of single genes and gene pyramiding have provided only limited success, due principally to the highly branched and complex biosynthetic pathway of the flavonoids. Transcription factors have been demonstrated as an efficient tool for metabolic engineering of this pathway, but often exhibit variation in heterologous systems relative to that in the homologous system. In the present work, Arabidopsis MYB transcription factor, AtMYB111, has been expressed in tobacco to study whether this can enhance flavonoid biosynthesis in heterologous system. The results suggest that AtMYB111 expression in transgenic tobacco enhances expression of genes of the phenylpropanoid pathway leading to an elevated content of flavonols. However, dark incubation of transgenic and wild type (WT) plants down-regulated both the expression of genes as well as flavonoid content as compared to light grown plants. The study concludes that AtMYB111 can be effectively used in heterologous systems, however, light is required for its action in modulating biosynthetic pathway.

Teaching community medicine to medical undergraduates-learning by doing: our experience of rural posting at All India Institute of Medical Sciences, New Delhi, India

BACKGROUND

The goal of medical education is to ensure that the medical graduate has acquired broad public health competencies needed to solve the health problems of the community. We present the current teaching of community medicine to medical students of the All India Institute of Medical Sciences (AIIMS), New Delhi during their 5-week posting at the rural centre at Ballabgarh, Haryana.

METHODS

The teaching activities consist of field visits to different levels of health facilities and meeting with health workers, epidemiological exercises, a community-based exercise, posting in inpatient and outpatient departments of a secondary hospital, and domiciliary visits to families of patients. These are spread over 80 sessions of about 200 hours. There is very little didactic teaching and the assessment is broad-based. The evaluation of the posting was based on comparison of blinded pre- and post-posting assessments as well as anonymous feedback of the posting by the students.

RESULTS

There was a significant increase in the mean scores of all components of the posting-epidemiology (5.1 to 8.4), health systems (6.8 to 9.3) and clinical (8.0 to 10.8). The posting did not result in a better understanding of a public health approach as compared to a clinical approach. The feedback provided by students was generally positive for all activities with 94% of them rating it as good or very good.

CONCLUSION

The teaching of community medicine can be made more practical and interesting without compromising on learning. However, despite such a programme, getting medical students to develop a public health approach is a daunting task.

Co-expression of Arabidopsis transcription factor, AtMYB12, and soybean isoflavone synthase, GmIFS1, genes in tobacco leads to enhanced biosynthesis of isoflavones and flavonols resulting in osteoprotective activity

Isoflavones, a group of flavonoids, restricted almost exclusively to family Leguminosae are known to exhibit anticancerous and anti-osteoporotic activities in animal systems and have been a target for metabolic engineering in commonly consumed food crops. Earlier efforts based on the expression of legume isoflavone synthase (IFS) genes in nonlegume plant species led to the limited success in terms of isoflavone content in transgenic tissue due to the limitation of substrate for IFS enzyme. In this work to overcome this limitation, the activation of multiple genes of flavonoid pathway using Arabidopsis transcription factor AtMYB12 has been carried out. We developed transgenic tobacco lines constitutively co-expressing AtMYB12 and GmIFS1 (soybean IFS) genes or independently and carried out their phytochemical and molecular analyses. The leaves of co-expressing transgenic lines were found to have elevated flavonol content along with the accumulation of substantial amount of genistein glycoconjugates being at the highest levels that could be engineered in tobacco leaves till date. Oestrogen-deficient (ovariectomized, Ovx) mice fed with leaf extract from transgenic plant co-expressing AtMYB12 and GmIFS1 but not wild-type extract exhibited significant conservation of trabecular microarchitecture, reduced osteoclast number and expression of osteoclastogenic genes, higher total serum antioxidant levels and increased uterine oestrogenicity compared with Ovx mice treated with vehicle (control). The skeletal effect of the transgenic extract was comparable to oestrogen-treated Ovx mice. Together, our results establish an efficient strategy for successful pathway engineering of isoflavones and other flavonoids in crop plants and provide a direct evidence of improved osteoprotective effect of transgenic plant extract.

An improved Agrobacterium-mediated transformation of recalcitrant indica rice (Oryza sativa L.) cultivars

Agrobacterium-mediated transformation of indica rice varieties has been quite difficult as these are recalcitrant to in vitro responses. In the present study, we established a high-efficiency Agrobacterium tumefaciens-mediated transformation system of rice (Oryza sativa L. ssp. indica) cv. IR-64, Lalat, and IET-4786. Agrobacterium strain EHA-101 harboring binary vector pIG121-Hm, containing a gene encoding for β-glucuronidase (GUS) and hygromycin resistance, was used in the transformation experiments. Manipulation of different concentrations of acetosyringone, days of co-culture period, bacterial suspension of different optical densities (ODs), and the concentrations of L-cysteine in liquid followed by solid co-culture medium was done for establishing the protocol. Among the different co-culture periods, 5 days of co-culture with bacterial cells (OD600 nm = 0.5-0.8) promoted the highest frequency of transformation (83.04 %) in medium containing L-cysteine (400 mg l(-1)). Putative transformed plants were analyzed for the presence of a transgene through genomic PCR and GUS histochemical analyses. Our results also suggest that different cultural conditions and the addition of L-cysteine in the co-culture medium improve the Agrobacterium-mediated transformation frequencies from an average of 12.82 % to 33.33 % in different indica rice cultivars.

Prevalence of chronic kidney diseases and its determinants among perimenopausal women in a rural area of North India: A community-based study

The burden of noncommunicable diseases is rising in India. A high prevalence of lifestyle-related diseases in perimenopausal women in the community makes them vulnerable to chronic kidney diseases (CKD). A cross-sectional community-based study was carried out among women >35 years of age in the village of Ballabgarh, Haryana (north India). Eligible women were selected by the probability proportionate to size sampling method. Estimation of glomerular filtration rate (GFR) was carried out by using the age- and body surface area (BSA)-adjusted Cockcroft–Gault (CG) and modification of diet in renal disease (MDRD) equations. Association of risk factors such as obesity, hyperlipidemia, hypertension, and diabetes mellitus with CKD was also assessed using multivariate logistic regression analysis. A total of 455 women were studied. The prevalence of low GFR (<60 mL/min/1.73 m²) by the CG/BSA equations and MDRD equation was found to be 18.2% (95% confidence interval 14.6, 21.8) and 5.9% (95% confidence interval 3.7, 8.1), respectively. Obesity (odds ratio 15.5) (P = 0.002), hyperlipidemia (odds ratio: 2.5) (P = 0.017), and age (P < 0.001) were significantly associated with reduced GFR on multivariate logistic regression analysis. This study observed a high prevalence of CKD and its risk factors among perimenopausal women in a rural community in north India. The study highlights the need of a multipronged, community-based intervention strategy that includes a high-risk screening approach and awareness generation about CKD and its risk factors in the community.