The sterol-sensing domain (SSD) directly mediates signal-regulated endoplasmic reticulum-associated degradation (ERAD) of 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase isozyme Hmg2

The sterol-sensing domain (SSD) is a conserved motif in membrane proteins responsible for sterol regulation. Mammalian proteins SREBP cleavage-activating protein (SCAP) and HMG-CoA reductase (HMGR) both possess SSDs required for feedback regulation of sterol-related genes and sterol synthetic rate. Although these two SSD proteins clearly sense sterols, the range of signals detected by this eukaryotic motif is not clear. The yeast HMG-CoA reductase isozyme Hmg2, like its mammalian counterpart, undergoes endoplasmic reticulum (ER)-associated degradation that is subject to feedback control by the sterol pathway. The primary degradation signal for yeast Hmg2 degradation is the 20-carbon isoprene geranylgeranyl pyrophosphate, rather than a sterol. Nevertheless, the Hmg2 protein possesses an SSD, leading us to test its role in feedback control of Hmg2 stability. We mutated highly conserved SSD residues of Hmg2 and evaluated regulated degradation. Our results indicated that the SSD was required for sterol pathway signals to stimulate Hmg2 ER-associated degradation and was employed for detection of both geranylgeranyl pyrophosphate and a secondary oxysterol signal. Our data further indicate that the SSD allows a signal-dependent structural change in Hmg2 that promotes entry into the ER degradation pathway. Thus, the eukaryotic SSD is capable of significant plasticity in signal recognition or response. We propose that the harnessing of cellular quality control pathways to bring about feedback regulation of normal proteins is a unifying theme for the action of all SSDs.     

Modification of radiation damage to mitochondrial system in vivo by Podophyllum hexandrum: Mechanistic aspects

The present study was undertaken to investigate whether RP-1 treatment protected mitochondrial system against radiation damage and also to unravel the mechanism associated with this process. Radioprotection of mitochondrial system by Podophyllum hexandrum (RP-1) was investigated to understand its mechanism of action. Levels of superoxide anion (O2-), reduced or oxidized glutathione (GSH or GSSG), thiobarbituric acid reactive substance (TBARS), protein carbonyl (PC), ATP, NADH-ubiquinone oxidoreductase (complex-I), NADH-cytochrome c oxidoreductase (complex I/II), succinate-cytochrome c oxidoreductase (complex II/III) and mitochondrial membrane potential (MMP) were studied in mitochondria isolated from liver of mice belonging to various treatment groups. Whole body y-irradiation (10 Gy) significantly (p < 0.01) increased the formation of O2-, PC, and TBARS, upto 24 h as compared to untreated control. RP-1 treatment (200 mg/kg b.w.) to mice 2 h before irradiation reduced the radiation-induced O2- generation within 4 h and formation of TBARS and PC upto 24 h significantly (p < 0.01). Singularly irradiation or RP-1 treatment significantly (p < 0.01) increased the levels of glutathione within an hour, as compared to untreated control. Pre-irradiation administration of RP-1 enhanced levels of GSH induced increase in complex I (upto 16 h), complex I/III (4 h) complex II/III activity (upto 24 h; p < 0.01) and inhibited the radiation-induced decrease in MMP significantly (24 h; p < 0.01). The present study indicates that RP-1 itself modulates several mitichondrial perameters due to its influence on the biochemical milieu within and outside the cells. However, RP-1 treatment before irradiation modulates radiation induced perturbations such as the increase in electron transport chain enzyme activity, formation of O2-, TBARS and PC to offer radioprotection.     

Lymphadenovarix in the axilla – an unusual presentation of filariasis

Clinical manifestations of lymphatic filariasis depend on the area of lymphatic involvement and the duration of infection. A 21 year old man, resident in a filariasis endemic region, presented with multiple matted lymph nodes with cystic areas forming a large mass in his left axilla. An ultrasound scan of the axilla using a 7.5 MHz transducer revealed grossly dilated lymphatics but no filarial dance sign. Fine needle (21 G) aspiration cytology (FNAC) from the dilated lymphatics and solid areas in the lymph node mass revealed multiple microfilariae in a background of reactive lymphoid cells. Peripheral blood smears revealed microfilaremia with significant eosinophilia. Diagnosis of left axillary Bancroftian lymphadenovarix was made. On the administration of oral diethylcarbamazine, the diameter of the lymphatic vessels in the lymphadenovarix reduced considerably in size and microfilaremia disappeared. We report this case because axillary lymphadenovarix is a rare presentation of filariasis. This case is also unique since microfilariae were demonstrated in the fluid aspirated from the dilated lymphatics of the lymphadenovarix in the absence of live adult worms.     

Neem components as potential agents for cancer prevention and treatment

Azadirachta indica, also known as neem, is commonly found in many semi-tropical and tropical countries including India, Pakistan, and Bangladesh. The components extracted from neem plant have been used in traditional medicine for the cure of multiple diseases including cancer for centuries. The extracts of seeds, leaves, flowers, and fruits of neem have consistently shown chemopreventive and antitumor effects in different types of cancer. Azadirachtin and nimbolide are among the few bioactive components in neem that have been studied extensively, but research on a great number of additional bioactive components is warranted. The key anticancer effects of neem components on malignant cells include inhibition of cell proliferation, induction of cell death, suppression of cancer angiogenesis, restoration of cellular reduction/oxidation (redox) balance, and enhancement of the host immune responses against tumor cells. While the underlying mechanisms of these effects are mostly unclear, the suppression of NF-κB signaling pathway is, at least partially, involved in the anticancer functions of neem components. Importantly, the anti-proliferative and apoptosis-inducing effects of neem components are tumor selective as the effects on normal cells are significantly weaker. In addition, neem extracts sensitize cancer cells to immunotherapy and radiotherapy, and enhance the efficacy of certain cancer chemotherapeutic agents. This review summarizes the current updates on the anticancer effects of neem components and their possible impact on managing cancer incidence and treatment.     

Phenological variations of primary biochemicals in male and female plants of Hippophae salicifolia D. Don

Journal of Plant Biochemistry and Biotechnology - Dioecious nature of a plant shows variations in male and female individuals of that species, due to their differential role in sexual reproduction....     

Sanitation,Stress, and Life Stage: A Systematic Data Collection Study among Women in Odisha,India

Emerging evidence demonstrates how inadequate access to water and sanitation is linked to psychosocial stress, especially among women, forcing them to navigate social and physical barriers during their daily sanitation routines. We examine sanitation-related psychosocial stress (SRPS) across women’s reproductive lives in three distinct geographic sites (urban slums, rural villages, and rural tribal villages) in Odisha, India. We explored daily sanitation practices of adolescent, newly married, pregnant, and established adult women (n = 60) and identified stressors encountered during sanitation. Responding to structured data collection methods, women ranked seven sanitation activities (defecation, urination, menstruation, bathing, post-defecation cleaning, carrying water, and changing clothes) based on stress (high to low) and level of freedom (associated with greatest freedom to having the most restrictions). Women then identified common stressors they encountered when practicing sanitation and sorted stressors in constrained piles based on frequency and severity of each issue. The constellation of factors influencing SRPS varies by life stage and location. Overall, sanitation behaviors that were most restricted (i.e., menstruation) were the most stressful. Women in different sites encountered different stressors, and the level of perceived severity varied based on site and life stage. Understanding the influence of place and life stage on SRPS provides a nuanced understanding of sanitation, and may help identify areas for intervention.     

Continuous biosynthesis of abscisic acid (ABA) may be required for maintaining dormancy of isolated embryos and intact seeds of Euonymus alatus

Euonymus alatus (Thunb.) Sieb. is a popular landscape plant in the United States due to its brilliant red fall foliage. It is also an important ornamental plant in many other areas of the world such as China, Japan and Europe. However, E. alatus is considered as a highly invasive plant species in the US. Mutation breeding can be used to create sterile, non-invasive cultivars. Seeds are the most commonly used explants for mutagen treatments, but E. alatus mature seeds possess prolonged dormancy and only a low percentage of them germinate even after 18?months of cold stratification. Here we report an immature embryo culture method for E. alatus ??Compactus?? to circumvent the seed dormancy problem. Also, we have found that activated charcoal, gibberellic acid (GA₃) and 6-benzyladenine (BA) can reduce the dormancy of isolated embryos, which suggests that abscisic acid (ABA) might play a role in controlling seed dormancy. We have further demonstrated that exogenous ABA enhances dormancy of isolated E. alatus embryos while fluridone, an inhibitor for ABA biosynthesis, can effectively break their dormancy. These results, particularly the effect of fluridone, suggest that continuous ABA biosynthesis plays an important role in controlling the dormancy of E. alatus seeds.     

A Unique Protein Phosphatase with Kelch-Like Domains (PPKL) in Plasmodium Modulates Ookinete Differentiation,Motility and Invasion

Protein phosphorylation and dephosphorylation (catalysed by kinases and phosphatases, respectively) are post-translational modifications that play key roles in many eukaryotic signalling pathways, and are often deregulated in a number of pathological conditions in humans. In the malaria parasite Plasmodium, functional insights into its kinome have only recently been achieved, with over half being essential for blood stage development and another 14 kinases being essential for sexual development and mosquito transmission. However, functions for any of the plasmodial protein phosphatases are unknown. Here, we use reverse genetics in the rodent malaria model, Plasmodium berghei, to examine the role of a unique protein phosphatase containing kelch-like domains (termed PPKL) from a family related to Arabidopsis BSU1. Phylogenetic analysis confirmed that the family of BSU1-like proteins including PPKL is encoded in the genomes of land plants, green algae and alveolates, but not in other eukaryotic lineages. Furthermore, PPKL was observed in a distinct family, separate to the most closely-related phosphatase family, PP1. In our genetic approach, C-terminal GFP fusion with PPKL showed an active protein phosphatase preferentially expressed in female gametocytes and ookinetes. Deletion of the endogenous ppkl gene caused abnormal ookinete development and differentiation, and dissociated apical microtubules from the inner-membrane complex, generating an immotile phenotype and failure to invade the mosquito mid-gut epithelium. These observations were substantiated by changes in localisation of cytoskeletal tubulin and actin, and the micronemal protein CTRP in the knockout mutant as assessed by indirect immunofluorescence. Finally, increased mRNA expression of dozi, a RNA helicase vital to zygote development was observed in ppkl⁻ mutants, with global phosphorylation studies of ookinete differentiation from 1.5–24 h post-fertilisation indicating major changes in the first hours of zygote development. Our work demonstrates a stage-specific essentiality of the unique PPKL enzyme, which modulates parasite differentiation, motility and transmission.     

Involvement of calcitonin gene-related peptide in control of human fetoplacental vascular tone

Calcitonin gene-related peptide (CGRP), one of the most potent endogenous vasodilators known, has been implicated in vascular adaptations and placental functions during pregnancy. The present study was designed to examine the existence of CGRP-A receptor components, the calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein 1 (RAMP1), in the human placenta and the vasoactivity of CGRP in the fetoplacental circulation. Immunofluorescent staining of the human placenta in term labor using polyclonal anti-CRLR and RAMP1 antibodies revealed that labeling specifically concentrated in the vascular endothelium and the underlying smooth muscle cells in the umbilical artery/vein, chorionic artery/vein, and stem villous vessels as well as in the trophoblast layer of the placental villi. In vitro isometric force measurement showed that CGRP dose dependently relaxes the umbilical artery/vein, chorionic artery/vein, and stem villous vessels. Furthermore, CGRP-induced relaxation of placental vessels are inhibited by a CGRP receptor antagonist (CGRP8-37), ATP-sensitive potassium (KATP) channel blocker (glybenclamide), and cAMP-dependent protein kinase A inhibitor (Rp-cAMPS) and partially inhibited by a nitric oxide inhibitor (Nomega-nitro-l-arginine methyl ester). We propose that CGRP may play a role in the control of human fetoplacental vascular tone, and the vascular dilations in response to CGRP may involve activation of KATP channels, cAMP, and a nitric oxide pathway.     

Effect of chloride on ferrous iron oxidation by a Leptospirillum ferriphilum‐dominated chemostat culture

Biomining is the use of microorganisms to catalyze metal extraction from sulfide ores. However, the available water in some biomining environments has high chloride concentrations and therefore, chloride toxicity to ferrous oxidizing microorganisms has been investigated. Batch biooxidation of Fe²⁺ by a Leptospirillum ferriphilum‐dominated culture was completely inhibited by 12 g L^?1 chloride. In addition, the effects of chloride on oxidation kinetics in a Fe²⁺ limited chemostat were studied. Results from the chemostat modeling suggest that the chloride toxicity was attributed to affects on the Fe²⁺ oxidation system, pH homeostasis, and lowering of the proton motive force. Modeling showed a decrease in the maximum specific growth rate (µ_max) and an increase in the substrate constant (K_s) with increasing chloride concentrations, indicating an effect on the Fe²⁺ oxidation system. The model proposes a lowered maintenance activity when the media was fed with 2–3 g L^?1 chloride with a concomitant drastic decrease in the true yield (Y_true). This model helps to understand the influence of chloride on Fe²⁺ biooxidation kinetics. Biotechnol. Bioeng. 2010; 106: 422–431. © 2010 Wiley Periodicals, Inc.