Drought stress tolerance in rice: a critical insight

Drought is currently a serious threat for farming especially in rice cultivation, due to its substantial water requirements throughout its lifecycle. Drought is one of the major environmental constraints disrupting the growth and yield of rice plants, affecting them at physiological, morphological, biochemical and molecular levels. Global climate change exacerbates this issue, leading to substantial economic losses. As rice is a major food crop worldwide, the demand for rice production is increasing in tandem with the expanding human population. Consequently, it has become imperative to utilize drought-prone areas for agriculture and develop drought-tolerant rice genotypes. In addition to conventional breeding methods, the application of multi-omics approaches proves most effective in meeting the need to enhance drought tolerance in rice plants. Protective mechanisms, such as morphological adaptation, physiological acclimatization, cellular adjustments and antioxidant defense, play pivotal roles in helping plants overcome drought stress. Plant-microbial interactions are important for plants to overcome drought-induced adversities. Furthermore, applications of conventional approaches, omics approaches and nanotechnology are very promising for generating climate smart agriculture. Our aim in this review is to focus on drought stress tolerance in rice including drought-tolerant rice genotypes, their adaptation mechanisms, the unveiling the genes, transcription factors, microRNAs (miRNA) involved, microbial assistance and exploring approaches to mitigate drought stress in rice plants. The present review might throw some light on understanding the mechanism of drought stress tolerance in rice, including its molecular crosstalk and biochemical dynamics, for future researchers

Investigation on microfloral association in the roots of Macrotyloma uniflorum (Lam.) Verdc., a medicinally important tropical pulse-crop and their possible applications for crop improvement: a review

Macrotyloma uniflorum (Lam.) Verdc., an economically important medicinal plant belongs to the Leguminosae family. Being Afro-Asian origin, the plant has long tradition of uses. It is primarily used for its antiurolithiatic property although it has other medicinal uses. Being Leguminosae member, this plant can form rhizobial nodules and mycorrhizal associations. The rhizobia obtained from this plant are mostly belonged to Bradyrhizobium sp. Although, Rhizobium pusence has also been reported. Microbes as biofertilizers can be used to increase yield of this plant, as well as there is great potential for utilizing the microbes derived from this plant. In this review we aim to describe the plant M. uniflorum - its taxonomic characteristics, economic uses, putative active constituents, and beneficial microflora along with their applications

Constitutive association of Mcm2-3-5 proteins with chromatin in Entamoeba histolytica

Eukaryotic cells duplicate their genome once and only once per cell cycle. Our earlier studies with the protozoan parasite, Entamoeba histolytica, have shown that genome reduplication may occur several times ?without ?nuclear ?or ?cellular ?division. ?The Mcm2-7 protein complex is required for licensing of DNA replication. In an effort to understand whether genome reduplication occurs due to absence or failure of the DNA replication licensing system, we analysed the function of Mcm2-3-5 proteins in E. histolytica. In this study, we have cloned E. histolytica (Eh) MCM2 and Eh MCM5 genes, while Eh MCM3 was cloned earlier. The sequence of Eh MCM2-3-5 genes is well conserved with other eukaryotic homologues. We have shown that Eh Mcm2,3 proteins are functional in Saccharomyces cerevisiae. Our studies in E. histolytica showed that Eh Mcm2-3-5 proteins are associated with chromatin constitutively in cycling cells and during arrest of DNA synthesis induced by serum starvation. Alternation of genome duplication with mitosis is regulated by association-dissociation of Mcm2-7 proteins with chromatin in other eukaryotes. Our results suggest that constitutive association of Mcm proteins with chromatin could be one of the reasons why genome reduplication occurs in E. histolytica

Genome re-duplication and irregular segregation occur during the cell cycle of Entamoeba histolytica

Heterogeneity of genome content is commonly observed in axenic cultures of Entamoeba histolytica. Cells with multiple nuclei and nuclei with heterogenous genome contents suggest that regulatory mechanisms that ensure alternation of DNA synthesis and mitosis are absent in this organism. Therefore, several endo-reduplicative cycles may occur without mitosis. The data also shows that unlike other endo-reduplicating organisms, E.histolytica does not undergo a precise number of endo-reduplicative cycles. We propose that irregular endo-reduplication and genome partitioning lead to heterogeneity in the genome content of E.histolytica trophozoites in their proliferative phase. The goal of future studies should be aimed at understanding the mechanisms that are involved in (a) accumulation of multiple genome contents in a single nucleus; (b) genome segregation in nuclei that contain multiple genome contents and (c) maintenance of genome fidelity in E. histolytica

Inter-Cellular Variation in DNA Content of Entamoeba histolytica Originates from Temporal and Spatial Uncoupling of Cytokinesis from the Nuclear Cycle

Accumulation of multiple copies of the genome in a single nucleus and several nuclei in a single cell has previously been noted in Entamoeba histolytica, contributing to the genetic heterogeneity of this unicellular eukaryote. In this study, we demonstrate that this genetic heterogeneity is an inherent feature of the cell cycle of this organism. Chromosome segregation occurs on a variety of novel microtubular assemblies including multi-polar spindles. Cytokinesis in E. histolytica is completed by the mechanical severing of a thin cytoplasmic bridge, either independently or with the help of neighboring cells. Importantly, cytokinesis is uncoupled from the nuclear division cycle, both temporally and spatially, leading to the formation of unequal daughter cells. Sorting of euploid and polyploid cells showed that each of these sub-populations acquired heterogeneous DNA content upon further growth. Our study conclusively demonstrates that genetic heterogeneity originates from the unique mode of cell division events in this protist

Entamoeba Shows Reversible Variation in Ploidy under Different Growth Conditions and between Life Cycle Phases

Under axenic growth conditions, trophozoites of Entamoeba histolytica contain heterogenous amounts of DNA due to the presence of both multiple nuclei and different amounts of DNA in individual nuclei. In order to establish if the DNA content and the observed heterogeneity is maintained during different growth conditions, we have compared E. histolytica cells growing in xenic and axenic cultures. Our results show that the nuclear DNA content of E. histolytica trophozoites growing in axenic cultures is at least 10 fold higher than in xenic cultures. Re-association of axenic cultures with their bacterial flora led to a reduction of DNA content to the original xenic values. Thus switching between xenic and axenic growth conditions was accompanied by significant changes in the nuclear DNA content of this parasite. Changes in DNA content during encystation-excystation were studied in the related reptilian parasite E. invadens. During excystation of E. invadens cysts, it was observed that the nuclear DNA content increased approximately 40 fold following emergence of trophozoites in axenic cultures. Based on the observed large changes in nuclear size and DNA content, and the minor differences in relative abundance of representative protein coding sequences, rDNA and tRNA sequences, it appears that gain or loss of whole genome copies may be occurring during changes in the growth conditions. Our studies demonstrate the inherent plasticity and dynamic nature of the Entamoeba genome in at least two species

Barriers to Help-Seeking for South Asian Immigrant Survivors of Intimate Partner Violence (IPV): An Interpretative Phenomenological Study

South Asians constitute one of the largest immigrant populations in the country; yet their visibility in domestic violence literature continues to be limited. Insufficient representation of this group and discrepancies in prevalence rates occur because women in this community who are survivors of IPV, rarely approach formal or informal sources of assistance. The aim of this qualitative interpretative phenomenological study is to delineate the experiences of South Asian immigrant women when they attempt to seek help for abuse. Specifically, this research will explore experiences that are perceived by these survivors’ as sociocultural and structural barriers which prevent or delay their ability to approach family, friends, community members, police, lawyers, domestic violence shelters, and non-governmental organizations for assistance. The present study will also describe their encounters with these formal and informal agencies as well as their opinions of potential additions and modifications to existing support services that would facilitate the help-seeking behavior of other South Asian immigrant women. Findings from this study detailed IPV experiences and survivors’ responses to abuse. Data obtained from participants indicated that self-blame, shame, financial dependence, cultural variables (e.g., gender roles, religiosity), lack of support, complications due to immigration status, and inappropriate behaviors from formal and informal agencies made it difficult for these women to seek assistance for IPV. The study details participants’ opinions on supplementary services that would help other South Asian immigrant women in similar circumstances. This dissertation also documents the additional hardships imposed on these survivors due to repercussions of the COVID-19 pandemic. Implications for practice, policy, and research are discussed

Synthesis, characterization, spectroscopic and electrochemical studies of new thioether ligated octahedral low-spin cobalt(II) complex: Oxidative cleavage of C-S bond

1126-1130The reaction of cobalt (II) acetate tetrahydrate with dithiaalkyl substituted arylazo-oxime ligand HON=C(Ph)N=NC6H4S(CH2)2SC6H4N=NC(Ph)=NOH (H2PhL).1, affords a thioether ligated octahedral low-spin [CoII (PhL)]. 2, (d7,  t2g6e1 , S = 1/2) with CoN4S2 coordination. The room temperature magnetic moment of solid [CoII (PhL)] is 1.88 μB. The low-spin configuration is further authenticated by it s eight line EPR spectra (g = 2.02, A = 31G) in frozen acetonitrile (77 K). The complex displays a quasi-reversible (ΔEp = 90 mV) one-electron cyclic response in acetonitrile at 0.08 V versus saturated calomel electrode. The response is assigned to the [CoII (PhL)]/[ CoII (PhL)t oxidation. Moreover, the bivalent [CoII (Ph L)], 2, undergoes an oxidative cleavage of the C-S bond to afford parent [CoII (PhL)ClO4]. 3, and transformed [CoII (PhLʹ)(PhLʹʹ)], complexes in their trivalent state. In CDCl3, the splitting of the vinylic protons of [CoII (PhLʹ)(PhLʹʹ)], 4. appears at δ5.85 (dd), 5.66 (dd) and 5.58 (dd), respectively (dd =doublet of doublet). All complexes have been characterized with the help of C, H, N analysis. FAB mass, cyclic voltammetry, spectroscopic techniques (UV-vis,1H NMR and EPR) and magnetic studies

The Cytoplasmic Capping Complex Assembles on Adapter Protein Nck1 Bound to the Proline-Rich C-Terminus of Mammalian Capping Enzyme

<div><p>Cytoplasmic capping is catalyzed by a complex that contains capping enzyme (CE) and a kinase that converts RNA with a 5′-monophosphate end to a 5′ diphosphate for subsequent addition of guanylic acid (GMP). We identify the proline-rich C-terminus as a new domain of CE that is required for its participation in cytoplasmic capping, and show the cytoplasmic capping complex assembles on Nck1, an adapter protein with functions in translation and tyrosine kinase signaling. Binding is specific to Nck1 and is independent of RNA. We show by sedimentation and gel filtration that Nck1 and CE are together in a larger complex, that the complex can assemble <i>in vitro</i> on recombinant Nck1, and Nck1 knockdown disrupts the integrity of the complex. CE and the 5′ kinase are juxtaposed by binding to the adjacent domains of Nck1, and cap homeostasis is inhibited by Nck1 with inactivating mutations in each of these domains. These results identify a new domain of CE that is specific to its function in cytoplasmic capping, and a new role for Nck1 in regulating gene expression through its role as the scaffold for assembly of the cytoplasmic capping complex.</p></div