Sleep Disturbance and Alzheimer’s Disease: The Glial Connection

Poor quality and quantity of sleep are very common in elderly people throughout the world. Growing evidence has suggested that sleep disturbances could accelerate the process of neurodegeneration. Recent reports have shown a positive correlation between sleep deprivation and amyloid-β (Aβ)/tau aggregation in the brain of Alzheimer’s patients. Glial cells have long been implicated in the progression of Alzheimer’s disease (AD) and recent findings have also suggested their role in regulating sleep homeostasis. However, how glial cells control the sleep–wake balance and exactly how disturbed sleep may act as a trigger for Alzheimer’s or other neurological disorders have recently gotten attention. In an attempt to connect the dots, the present review has highlighted the role of glia-derived sleep regulatory molecules in AD pathogenesis.

Graphical Abstract

Role of glia in sleep disturbance and Alzheimer’s progression.

     

Effect of 24-epibrassinolide on oxidative stress markers induced by nickel-ion in <Emphasis Type="Italic">Raphanus sativus</Emphasis> L.

The present study illustrates the effect of 24-epibrassinolide (24-EBL) on morphological and biochemical parameters in radish (Raphanus sativus L.) seedlings grown under nickel (Ni) ion stress. The radish seeds pre-soaked in different concentrations of 24-EBL were sown in petridishes containing various concentrations of heavy metal (Ni).Observations were made on root/shoot length, fresh biomass, activities of antioxidant enzymes (ascorbate peroxidase, superoxide dismutase, catalase, monodehydroascorbate reductase, dehydroascorbate reductase, guaiacol peroxidase and glutathione reductase), lipid peroxidation, proline and protein content in 7-day-old Ni-stressed radish seedlings. Results indicate that seeds presoaked with 24-EBL reduced the impact of Ni-stress which was evident by assessing the morphological parameters, protein content and antioxidant enzyme activities. It was also observed that 24-EBL reduced the toxicity of heavy metal by influencing proline and malondialdehyde (MDA) content. The present study lays a foundation for understanding the role of 24-EBL in heavy metal stress amelioration, particularly in food crop. Analysis of behaviour of antioxidant enzymes will play a critical role in understanding the stress networking, further filling the knowledge gap on the subject.     

Schistosome apyrase SmATPDase1, but not SmATPDase2, hydrolyses exogenous ATP and ADP

Schistosomes are parasitic worms that can live in the bloodstream of their vertebrate hosts for many years. It has been proposed that the worms impinge on host purinergic signalling by degrading proinflammatory molecules like ATP as well as prothrombotic mediators like ADP. This capability may help explain the apparent refractoriness of the worms to both immune elimination and thrombus formation. Three distinct ectoenzymes, expressed at the host-exposed surface of the worm’s tegument, are proposed to be involved in the catabolism of ATP and ADP. These are alkaline phosphatase (SmAP), phosphodiesterase (SmNPP-5), and ATP diphosphohydrolase (SmATPDase1). It has recently been shown that only one of these enzymes—SmATPDase1—actually degrades exogenous ATP and ADP. However, a second ATP diphosphohydrolase homolog (SmATPDase2) is located in the tegument and has been reported to be released by the worms. It is possible that this enzyme too participates in the cleavage of exogenous nucleotide tri- and di-phosphates. To test this hypothesis, we employed RNA interference (RNAi) to suppress the expression of the schistosome SmATPDase1 and SmATPDase2 genes. We find that only SmATPDase1-suppressed parasites are significantly impaired in their ability to degrade exogenously added ATP or ADP. Suppression of SmATPDase2 does not appreciably affect the worms’ ability to catabolize ATP or ADP. Furthermore, we detect no evidence for the secretion or release of an ATP-hydrolyzing activity by cultured parasites. The results confirm the role of tegumental SmATPDase1, but not SmADTPDase2, in the degradation of the exogenous proinflammatory and prothrombotic nucleotides ATP and ADP by live intravascular stages of the parasite.     

Multivariate analysis on the distribution of elements in plants

The present review accentuates the elemental composition of plants as investigated by various researchers utilizing sophisticated techniques. Plants contain plethora of elements which extend their benefits to humans both in terms of medicine as well as nutrition. Therefore, there is a need to explore the elemental composition of plants to investigate their nutraceutical importance. In this review, the elemental data was analyzed using different multivariate techniques. The average values of elements used in this review are sodium (Na) (241.1 µg/g dw), magnesium (Mg) (1202.4 µg/g dw), aluminum (Al) (159.6 µg/g dw), silicon (Si) (133.7 µg/g dw), phosphorus (P) (1947 µg/g dw), sulfur (S) (1483.1 µg/g dw), chloride (Cl) (624.5 µg/g dw), potassium (K) (3008.5 µg/g dw), calcium (Ca) (1663.1 µg/g dw) and iron (Fe) (143.6 µg/g dw) respectively. Maximum accumulation of Na, K, Ca, Mg, Fe, P and S occurs in Poaceae, Lamiaceae, Lauraceae, Sapotaceae, Apiaceae, Pedaliaceae and Brassicaceae, respectively.     

Studies on the Relationship of Urdbean Leaf Crinkle Virus and its Vectors, Aphis craccivora and Acyrthosiphon pisum

Pre and Post-virus-acquisition starvation of Aphis craccivora Koch, and Acyrthosiphon pisum Harris resulted in appreciable increase in percentage of transmission of urdbean leaf crinkle virus. Highest transmission occured when aphids were starved for 90 min prior to virus-acquisition. A. pisum and A. craccivora on 20 and 80 min of post-acquisition starvation and 10 and 20 min of virus-acquisition, respectively inoculated more number of plants. Both the aphids transmitted the virus in probes lasting for one min. However, beyond 5 min of successive transfer on test plants loss in transmissibility was apparent. Viruliferous aphid off the plant retained the virus for a much longer period than on maize plant. The virus appears to be non-persistently borne in the aphids.     

Antagonistic effects of EDTA against biochemical toxicity induced by Cr(VI) in Hordeum vulgare L. seedlings

The present study aims at the amelioration of chromium Cr(VI) toxicity using ethylenediaminetetraacetic acid (EDTA), and to understand the interactive effects of Cr(VI) and EDTA with respect to seedling growth, lipid peroxidation as assessed from malondialdehyde, pigments and antioxidative enzymes in Hordeum vulgare L. Following multivariate statistical techniques were used to study binary interactions between Cr(VI) and EDTA: 2-way ANOVA, Tukey’s multiple comparison test, multiple regression with interaction between Cr an EDTA, beta coefficients, path analysis and non-metric multidimensional scaling (NMDS). The present study revealed that the EDTA decreases lipid peroxidation induced by Cr(VI) and ameliorates the antioxidative defence system and pigment constitution of seedlings grown in Cr(VI) containing media. EDTA–Cr(VI) interaction decreased the Cr content in the seedlings which may be attributed to the chelating effect of EDTA. The root and shoot bioconcentration factors, the ratio of Cr content in the plant to that in the medium, were decreased by addition of EDTA to Cr(VI), indicating a decrease in the uptake of Cr by the seedlings from the medium. NMDS revealed that the ranking of the studied parameters is maintained by ordination on two axes. The study established that EDTA is antagonistic to Cr(VI) induced biochemical toxicity, and improves the antioxidative defence system, increases the chlorophyll content, and decreases Cr uptake in barley seedlings.     

Recent advances in ZnO nanostructure as a gas-sensing element for an acetone sensor: a short review

Air pollution is a severe concern globally as it disturbs the health conditions of living beings and the environment because of the discharge of acetone molecules. Metal oxide semiconductor (MOS) nanomaterials are crucial for developing efficient sensors because of their outstanding chemical and physical properties, empowering the inclusive developments in gas sensor productivity. This review presents the ZnO nanostructure state of the art and notable growth, and their structural, morphological, electronic, optical, and acetone-sensing properties. The key parameters, such as response, gas detection limit, sensitivity, reproducibility, response and recovery time, selectivity, and stability of the acetone sensor, have been discussed. Furthermore, gas-sensing mechanism models based on MOS for acetone sensing are reported and discussed. Finally, future possibilities and challenges for MOS (ZnO)-based gas sensors for acetone detection have also been explored.     

Computational investigation on effect of mutations in PCNA resulting in structural perturbations and inhibition of mismatch repair pathway

Abstract

From bacteria to mammals, DNA mismatch repair (MMR) pathway plays an essential role in eliminating mismatched nucleotides and insertion-deletion mismatches during the process of DNA replication. Among many of the proteins which participate in the mismatch repair process, proliferating cell nuclear antigen (PCNA) remains the principal conductor at the replication fork. The pol30-201 and pol30-204 are the two mutated alleles which encode for C22Y and C81R mutant forms of PCNA proteins. We performed long term molecular dynamics (MD) simulations analysis (0.8 μs) to understand the dynamic behavior and alterations in the structure of wild type and mutated forms of PCNA at the atomic level. We observed changes in the structural characteristics like length, radius, rise per residue of alpha helices in both the mutated forms of PCNA. Apart from it, disfigurement of the charge distribution which effects binding with the dsDNA due to mutant C22Y and other structural perturbations were also seen in regions significant for the formation of a biologically active trimeric form of PCNA due to mutant C81R. Our analysis of native and mutated forms of PCNA provides an insight into the essential structural and functional features required for proper and well-coordinated DNA mismatch repair process and consequences of the mutation leading to an impaired process of MMR. These structural characteristics are fundamental for the MMR process and hence our analysis likely contributes to or presents the novel mechanism involved in the process of MMR.

Communicated by Ramaswamy H. Sarma