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Author Archives:
Thymus atlanticus Supplementation Attenuates Hepatic Steatosis in High-Fat Diet Fed Guinea Pigs
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Ethnobotanical Study Among Tribal Communities of Kalimpong, West Bengal
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Hormonal Regulatory Impacts of Tinospora cordifolia Leaf Extract and Its Loaded Phytoniosome on Mifepristone-Induced Polycystic Ovarian Syndrome (PCOS) Rats – In Vivo Studies
Reduced iron and cobalt levels in response to curcumin supplementation are not responsible for the prolonged larval development and do not affect the oxidative stress tolerance and polyamine status of D. melanogaster
Curcumin supplementation, similar to the iron chelator bathophenanthroline, lowered the iron but also the cobalt content, and to a lesser extent affected the manganese and zinc status of D. melanogaster. However, these alterations in trace metal balance did not affect catalase activity, oxidative stress tolerance, and polyamine status in fruit flies. In contrast, in curcumin-supplemented mice, the spleen exhibits an elevated spermidine production, which is most probably related to a compensatory growth due to curcumin-induced iron deficiency.
Abstract
Recent reports indicated that the phytochemical curcumin possesses iron-chelating activity. Here, by employing the fruit fly Drosophila melanogaster, we conducted feeding studies supplementing curcumin or, as a control, the iron chelator bathophenanthroline (BPA). First, the absorption and further metabolization of dietary curcuminoids were proved by metabolomics analyses. Next, we found that 0.2% dietary curcumin, similar to BPA, lowered the iron but also the cobalt content, and to a lesser extent affected the manganese and zinc status. Supplementation during larval stages was required and sufficient for both compounds to elicit these alterations in adult animals. However, curcumin-induced retarded larval development was not attributable to the changed trace metal status. In addition, a reduction in the iron content of up to 70% by curcumin or BPA supplementation did not reduce heme-dependent catalase activity and tolerance toward H2O2 in D. melanogaster. Moreover, polyamines were not influenced by curcumin treatment and decreased iron levels. This was confirmed for selected organs from 0.2% curcumin-treated mice, except for the spleen. Here, elevated spermidine level and concomitant upregulation of genes involved in polyamine production were associated with a putatively anemia-derived increased spleen mass. Our data underline that the metal-chelating property of curcumin needs to be considered in feeding studies.
Dapagliflozin improves diabetic cognitive impairment via indirectly modulating the mitochondria homeostasis of hippocampus in diabetic mice
The goal of this study is to determine the underlying mechanism and look into dapagliflozin's impact on diabetic cognitive impairment. Diabetes-induced cognitive dysfunction was attenuated by dapagliflozin and the effect was indirect rather than direct.
Abstract
Cognitive impairment is increasingly recognized as an important comorbidity of diabetes progression; however, the underlying molecular mechanism is unclear. Dapagliflozin, an inhibitor of sodium-glucose co-transporter 2 (SGLT2), has shown promising effects against diabetes in rodent experiments and human clinical assays. This study aimed to determine the underlying mechanism and examine the effect of dapagliflozin on diabetic cognitive impairment. To create an in vivo model of diabetic cognitive impairment, streptozotocin (STZ)-induced diabetic mice were used. Dapagliflozin was administered to mice for 8 weeks. The context fear condition and Morris water maze test was used to evaluate mice's behavioral change. Western blotting was used to evaluate protein expression. Hematoxylin and eosin (HE) and Nissl staining were applied to monitor morphological and structural changes. Congo red staining was performed to identify the formation of senile plaques. Mitochondria morphology was examined using a transmission electron microscope, and blood flow in the mouse cerebral cortex was measured using a laser Doppler imaging assay. Comparison to the diabetes mellitus (DM) group, the dapagliflozin group had lower glucose levels. Behavioral studies have shown that dapagliflozin can restore memory deficits in diabetic mice. The murky cell membrane edges and Nissl bodies more difficult to identify in the DM group were revealed by HE and Nissl staining, which were both improved by dapagliflozin treatment. Dapagliflozin inhibited the progression of Aβ generation and the reduced cerebral blood flow in the DM group was rescued. After dapagliflozin treatment, damaged mitochondria and lack of SGLT2 in the hippocampus and cortex of diabetic mice were repaired. Diabetes-induced cognitive dysfunction was attenuated by dapagliflozin and the effect was indirect rather than direct.
k‐mer‐based GWAS enhances the discovery of causal variants and candidate genes in soybean
Abstract
Genome-wide association studies (GWAS) are powerful statistical methods that detect associations between genotype and phenotype at genome scale. Despite their power, GWAS frequently fail to pinpoint the causal variant or the gene controlling a given trait in crop species. Assessing genetic variants other than single-nucleotide polymorphisms (SNPs) could alleviate this problem. In this study, we tested the potential of structural variant (SV)- and k-mer-based GWAS in soybean by applying these methods as well as conventional SNP/indel-based GWAS to 13 traits. We assessed the performance of each GWAS approach based on loci for which the causal genes or variants were known from previous genetic studies. We found that k-mer-based GWAS was the most versatile approach and the best at pinpointing causal variants or candidate genes. Moreover, k-mer-based analyses identified promising candidate genes for loci related to pod color, pubescence form, and resistance to Phytophthora sojae. In our dataset, SV-based GWAS did not add value compared to k-mer-based GWAS and may not be worth the time and computational resources invested. Despite promising results, significant challenges remain regarding the downstream analysis of k-mer-based GWAS. Notably, better methods are needed to associate significant k-mers with sequence variation. Our results suggest that coupling k-mer- and SNP/indel-based GWAS is a powerful approach for discovering candidate genes in crop species.
In silico prediction and analysis of transmembrane‐coiled‐coil resistance gene analogues in 27 Brassicaceae species
A total of 6788 transmembrane-coiled-coil (TM-CCs) genes identified across 28 Brassicaceae species may play roles in plant defence and help improve crop disease resistance.
Abstract
The Brassicaceae family is composed of a broad range of species, including the economically important crops from Brassica, Raphanus, Camelina and Sinapis genera. The production of Brassicaceae species, particularly the crop members, is threatened by major diseases. However, the impact of diseases can be minimized or even negated by improving disease resistance. Transmembrane-coiled-coil (TM-CC) genes are a type of resistance gene analogue (RGA) that have been proven to play specific roles in resistance to several diseases. Here, TM-CCs have been predicted in 27 genomes from Brassicaceae genera including Arabidopsis, Arabis, Barbarea, Boechera, Brassica, Camelina, Capsella, Cardamine, Eutrema, Leavenworthia, Lepidium, Raphanus, Sinapis, Sisymbrium, Schrenkiella and Thlaspi. The number of TM-CCs varies throughout the studied genomes, as well as between genera, diploids and polyploids, and Brassica genomes and subgenomes. In total, 6788 TM-CCs were identified, with 708 of them predicted with signalling function, 172 colocalized with previously known disease resistance regions and 70 phylogenetically related to cloned resistance genes, indicating the possible functional involvement of TM-CCs in resistance. This study provides a resource for the identification of functional Brassicaceae TM-CCs along with their clustering and duplication patterns and provides a benchmark for further studies investigating TM-CCs.
Unravelling marker trait associations linking nutritional value with pigmentation in rice seed
Abstract
While considerable breeding effort has focused on increasing the yields of staple crops such as rice and the levels of micronutrients such as iron and zinc, breeding to address the problems of the double-burden of malnutrition has received less attention. Pigmented rice has higher nutritional value and greater health benefits compared to white rice. However, the genetic associations underlying pericarp coloration and accumulation of nutritionally valuable compounds is still poorly understood. Here we report the targeted genetic analysis of 364 rice accessions, assessing the genetic relationship between pericarp coloration (measured using multi-spectral imaging) and a range of phenolic compounds with potential nutritional and health-promoting characteristics. A genome-wide association study resulted in the identification of over 280 single nucleotide polymorphisms (SNPs) associated with the traits of interest. Many of the SNPs were associated with more than one trait, colocalization occurring between nutritional traits, and nutritional and color-related traits. Targeted association analysis identified 67 SNPs, located within 52 candidate genes and associated with 24 traits. Six haplotypes identified within the genes Rc/bHLH17 and OsIPT5 indicated that these genes have an important role in the regulation of a wide range of phenolic compounds, and not only those directly conferring pericarp color. These identified genetic linkages between nutritionally valuable phenolic compounds and pericarp color present not only a valuable resource for the enhancement of the nutritional value of rice but an easy method of selection of suitable genotypes.
Maize and heat stress: Physiological, genetic, and molecular insights
Abstract
Global mean temperature is increasing at a rapid pace due to the rapid emission of greenhouse gases majorly from anthropogenic practices and predicted to rise up to 1.5°C above the pre-industrial level by the year 2050. The warming climate is affecting global crop production by altering biochemical, physiological, and metabolic processes resulting in poor growth, development, and reduced yield. Maize is susceptible to heat stress, particularly at the reproductive and early grain filling stages. Interestingly, heat stress impact on crops is closely regulated by associated environmental covariables such as humidity, vapor pressure deficit, soil moisture content, and solar radiation. Therefore, heat stress tolerance is considered as a complex trait, which requires multiple levels of regulations in plants. Exploring genetic diversity from landraces and wild accessions of maize is a promising approach to identify novel donors, traits, quantitative trait loci (QTLs), and genes, which can be introgressed into the elite cultivars. Indeed, genome wide association studies (GWAS) for mining of potential QTL(s) and dominant gene(s) is a major route of crop improvement. Conversely, mutation breeding is being utilized for generating variation in existing populations with narrow genetic background. Besides breeding approaches, augmented production of heat shock factors (HSFs) and heat shock proteins (HSPs) have been reported in transgenic maize to provide heat stress tolerance. Recent advancements in molecular techniques including clustered regularly interspaced short palindromic repeats (CRISPR) would expedite the process for developing thermotolerant maize genotypes.