A microscopic scenario on recovery mechanisms under waterlogging and submergence stress in rice.

MAIN CONCLUSION: Adaptive traits in rice responding to flooding, a compound stress, are associated with morpho-anatomical and physiological changes which are regulated at the genetic level. Therefore, understanding submergence stress tolerance in rice will help development of adapted cultivars that can help mitigate agricultural losses. Rice is an important dietary component of daily human consumption and is cultivated as a staple crop worldwide. Flooding is a compound stress which imposes significant financial losses to farmers. Flood-affected rainfed rice ecosystems led to the development of various adaptive traits in different cultivars for their optimal growth and survival. Some cultivars can tolerate hypoxia by temporarily arresting elongation and conserving their energy sources, which they utilize to regrow after the stress conditions subside. However, few other cultivars rapidly elongate to escape hypoxia using carbohydrate resources. These contrasting characters are regulated at the genetic level through different quantitative trait loci that contain ERF transcription factors (TFs), Submergence and Snorkels. TFs can simultaneously activate the transcription of various genes involved in stress and development responses. These TFs are of prime importance because the introgressed and near-isogenic lines showed promising results with increased submergence tolerance without affecting yield or quality. However, the entire landscape of submergence tolerance is not entirely depicted, and further exploration in the field is necessary to understand the mechanism in rice completely. Therefore, this review will highlight the significant adaptive traits observed in flooded rice varieties and how they are regulated mechanistically.

The therapeutic potential of Houttuynia cordata: A current review.

The search and development of new drugs for the treatment of numerous illnesses afflicting humans of all ages is an unending endeavour. Moreover, there is constant demand to identify more compounds exhibiting pharmacological properties with improved efficacy and minimal side effects compared to the existing ones. Plants have always served as rich sources of pharmaceuticals, and offer better advantages than synthetic compounds in terms of diversity, production scale and safety. Houttuynia cordata is a traditional medicinal plant that is widely distributed in East Asia. Apart from its consumption as a delicacy in many countries, it has a rich history of medicinal use and numerous studies have reported its pharmacological activity against inflammation, cancer, viruses, bacteria, hyperglycaemia, obesity, etc. The various phytoconstituents that have been isolated from this plant include flavonoids, phenolic acids, volatile/essential oils and alkaloids whose therapeutic potentials are yet to be fully harnessed. This review provides an updated summary of the biological activity and therapeutic potential of H. cordata, its phytocompounds and derivatives. The amalgamation of traditional plant-derived medicines with modern scientific methods can provide better insights to their mechanism of action and also contribute greatly to the discovery and synthesis of new pharmaceuticals.

Toxic effects of smokeless tobacco on female reproductive health: A review.

The habitual consumption of tobacco in its various form is widespread and a serious public health issue globally. In particular, the use of smokeless tobacco has increased substantially due to its easy availability and misconception that it is relatively harmless compared to smoking. Tobacco use has been well established from numerous studies as a causative agent of devastating illnesses such as cancer, insulin resistance, hypertension, acute respiratory disease, osteoporosis, etc. Limited but growing evidence have also suggested its role in adversely affecting reproductive capabilities and outcomes in women of reproductive age and during pregnancy. This paper provides an updated review on available literature regarding the negative effects of smokeless tobacco use on female reproductive health, during pregnancy and its adverse consequences on the offspring. Existing data suggests the association between chronic smokeless tobacco use and impairment of ovarian morphology and function, oocyte quality, hormonal perturbations, fetal development and long-term health effects on the fetus. Improved understanding of these issues can contribute to better awareness of the dangers of smokeless tobacco products.

Expression profiling of c-kit and its impact after esiRNA silencing during gonadal development in catfish.

Receptor, c-Kit is a member of a family of growth factor receptors that have tyrosine kinase activity, and are involved in the transduction of growth regulatory signals across plasma membrane by activation of its ligand, kitl/scf. The present study analyzed mRNA and protein expression profiles of c-kit in the gonads of catfish, Clarias gariepinus, using real time PCR, in situ hybridization and immunohistochemistry. Tissue distribution analysis revealed higher expression mainly in the catfish gonads. Ontogeny studies showed minimal expression during early developmental stages and highest during 50-75 days post hatch, and the dimorphic expression in gonads decreased gradually till adulthood, which might suggest an important role for this gene around later stages of sex differentiation and gonadal development. Expression of c-kit was analyzed at various phases of gonadal cycle in both male and female, which showed minimal expression during the resting phase, and higher expression during the pre-spawning phase in male compared to females. In vitro and in vivo induction using human chorionic gonadotropin elevated the expression of c-kit indicating the regulatory influence of hypothalamo-hypophyseal axis. In vivo transient gene silencing using c-kit-esiRNA in adult catfish during gonadal recrudescence showed a decrease in c-kit expression, which affected the expression levels of germ cell meiotic marker sycp3, as well as several factors and steroidogenic enzyme genes that are involved in germ cell development. Decrease in the levels of 11-ketotestosterone and testosterone in serum were also observed after esiRNA silencing. The findings suggests that c-kit has an important role in the process of germ cell proliferation, development and maturation during gonadal development and recrudescence in catfish.

Two-dimensional proteomic analysis of gonads of air-breathing catfish, Clarias batrachus after the exposure of endosulfan and malathion.

Endocrine disrupting chemicals have raised public concern, since their effects have been found to interfere with the physiological systems of various organisms, especially during critical stage of development and reproduction. Endosulfan and malathion, pesticides widely used for agricultural purposes, have been known to disrupt physiological functions in aquatic organisms. The current work analyzes the effects of endosulfan (2.5 parts per billion [ppb]) and malathion (10 ppb) on the reproductive physiology of catfish (Clarias batrachus) by evaluating protein expression profiles after 21 days of exposure. The proteomic profile of testis and ovary after exposure to endosulfan showed downregulation of proteins such as ubiquitin and Esco2, and upregulation in melanocortin-receptor-2 respectively. Malathion exposed ovary showed upregulated prolactin levels. Identification of proteins differentially expressed in gonads due to the exposure to these pesticides may serve as crucial indications to denote their disruptive effects at the level of proteins.

Gene expression analysis in gonads and brain of catfish Clarias batrachus after the exposure of malathion.

Pesticides like malathion have the potential to disrupt development and reproduction of aquatic organisms including fishes. To investigate the likely consequences of malathion exposure at low doses in juvenile catfish, Clarias batrachus, we studied the expression pattern of genes encoding certain transcription factors, activin A, sex steroid or orphan nuclear receptors and steroidogenic enzymes which are known to be involved in gonadal development along with histological changes. To compare further, we also analyzed certain brain specific genes related to gonadal axis. Fifty days post hatch catfish fingerlings were exposed continuously to 1 and 10 µg/L of malathion for 21 days. Results from these experiments indicated that transcript levels of various genes were altered by the treatments, which may further affect the gonadal development either directly or indirectly through brain. Histological analysis revealed slow progression of spermatogenesis in testis, while in ovary, the oil droplet oocytes were found to be higher after treatment (10 µg/L). Our findings revealed that the exposure of malathion, even at low doses, hinder or modulate early gonadal development differentially by targeting gene expression pattern of transcription factors, activin A, sex steroid or orphan nuclear receptors and steroidogenic enzymes with an evidence on histological changes. Further, some of the genes showed differential expression at the level of brain in male and female sex after the exposure of malathion.

Endosulfan and flutamide impair testicular development in the juvenile Asian catfish, Clarias batrachus.

Endosulfan and flutamide, a widely used pesticide and a prostate cancer/infertility drug, respectively, have an increased risk of causing endocrine disruption if they reach water bodies. Though many studies are available on neurotoxicity/bioaccumulation of endosulfan and receptor antagonism of flutamide, only little is known about their impact on testicular steroidogenesis at molecular level. Sex steroids play an important role in sex differentiation of lower vertebrates including fishes. Hence, a small change in their levels caused by endocrine disruptors affects the gonadal development of aquatic vertebrates significantly. The aim of this study was to evaluate the effects of endosulfan and flutamide on testis-related transcription factor and steroidogenic enzyme genes with a comparison on the levels of androgens during critical period of catfish testicular development. We also analyzed the correlation between the above-mentioned genes and catfish gonadotropin-releasing hormone (cfGnRH)-tryptophan hydroxylase2 (tph2). The Asian catfish, Clarias batrachus males at 50 days post hatch (dph) were exposed to very low dose of endosulfan (2.5 µg/L) and flutamide (33 µg/L), alone and in combination for 50 days. The doses used in this study were far less than those used in the previous studies of flutamide and reported levels of endosulfan in surface water and sediments. Sampling was done at end of the treatments (100 dph) to perform testicular germ cell count (histology), measurements of testosterone (T) and 11-ketotestosterone (11-KT) by enzyme immunoassay and transcript quantification by quantitative real-time PCR. In general, treatments decreased the expression of several genes including testis-related transcription factors (dmrt1, sox9a and wt1), steroidogenic enzymes (11ß-hsd2, 17ß-hsd12 and P450c17), steroidogenic acute regulatory protein and orphan nuclear receptors (nr2c1 and Ad4BP/SF-1). In contrast, the transcripts of cfGnRH and tph2 were elevated in the brain of all treated groups with maximum elevation in the endosulfan group. However, combination of endosulfan and flutamide (E+F) treatment showed minor antagonism in a few results of transcript quantification. Levels of T and 11-KT were elevated after flutamide and E+F treatments while no change was seen in the endosulfan group signifying the effect of flutamide as an androgen receptor antagonist. All the treatments modulated testis growth by decreasing the progression of differentiation of spermatogonia to spermatocytes. Based on these results, we suggest that the exposure to endosulfan and flutamide, even at low doses, impairs testicular development either directly or indirectly at the level of brain.