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22
result(s) for
"Nayak, Arabinda"
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Targeting Nup358/RanBP2 by a viral protein disrupts stress granule formation
Viruses have evolved mechanisms to modulate cellular pathways to facilitate infection. One such pathway is the formation of stress granules (SG), which are ribonucleoprotein complexes that assemble during translation inhibition following cellular stress. Inhibition of SG assembly has been observed under numerous virus infections across species, suggesting a conserved fundamental viral strategy. However, the significance of SG modulation during virus infection is not fully understood. The 1A protein encoded by the model dicistrovirus, Cricket paralysis virus (CrPV), is a multifunctional protein that can bind to and degrade Ago-2 in an E3 ubiquitin ligase-dependent manner to block the antiviral RNA interference pathway and inhibit SG formation. Moreover, the R146 residue of 1A is necessary for SG inhibition and CrPV infection in both Drosophila S2 cells and adult flies. Here, we uncoupled CrPV-1A’s functions and provide insight into its underlying mechanism for SG inhibition. CrPV-1A mediated inhibition of SGs requires the E3 ubiquitin-ligase binding domain and the R146 residue, but not the Ago-2 binding domain. Wild-type but not mutant CrPV-1A R146A localizes to the nuclear membrane which correlates with nuclear enrichment of poly(A)+ RNA. Transcriptome changes in CrPV-infected cells are dependent on the R146 residue. Finally, Nup358/RanBP2 is targeted and degraded in CrPV-infected cells in an R146-dependent manner and the depletion of Nup358 blocks SG formation. We propose that CrPV utilizes a multiprong strategy whereby the CrPV-1A protein interferes with a nuclear event that contributes to SG inhibition in order to promote infection.
Journal Article
Spectral and temporal performance enhancement in a symmetric co-planar Au–Ge/AlGaAs/Au–Ge natural superlattice-based MSM photodetector
A comparative analysis is performed between a symmetric co-planar metal–semiconductor–metal Au–Ge/AlGaAs/Au–Ge photodetector based on naturally ordered superlattice structure in the semiconducting AlGaAs layer and the disordered AlGaAs layer as obtained by annealing the ordered sample at the order–disorder transition temperature. Before the device fabrication, the order to the disorder transition temperature of such periodic structure was determined by observing the X-ray rocking curves at different annealing temperatures and it was found to be 900 °C. The device operability of such structures was found within 400–900 nm of the electromagnetic spectrum. Under + 1 V bias, the peak responsivity, detectivity, and photosensitivity for the ordered sample were calculated to be 159.65 mA W
−1
, 1.22 × 10
13
cmHz
1/2
W
−1
, and 1.29 × 10
3
cm
2
W
−1
, respectively, and at − 1 V bias, these values were 20.67 mA W
−1
, 3.1 × 10
12
cmHz
1/2
W
−1
, and 165.35 cm
2
W
−1
, respectively in the presence of illumination of wavelength 750 nm at a fixed optical power. Whereas the device having homogeneous composition showed poor responsivity, detectivity, and photosensitivity of 22.58 mA W
−1
, 1.13 × 10
12
cmHz
1/2
W
−1
, and 45.15 cm
2
W
−1
, respectively at + 1 V and at − 1 V these values were 10.37 mA W
−1
, 1.04 × 10
12
cmHz
1/2
W
−1
, and 41.49 cm
2
W
−1
, respectively being peaked at 700 nm. Furthermore, the device with natural superlattice ordering showed superior temporal response with a rise time of 357 μs and decay times of 136 μs and 1.6 ms, respectively. The improvement of the photodetector performance using superlattice structures was explained considering the ordering-induced built-in electric field at the heterointerfaces under proper biasing conditions.
Journal Article
Preparation and evaluation of microstructure, dielectric and conductivity (ac/dc) characteristics of a polyaniline/poly N-vinyl carbazole/Fe3O4 nanocomposite
A poly N-vinyl carbazole- Fe
3
O
4
hybrid composite was prepared by solid state polymerization of N-vinyl carbazole (NVC) monomer in presence of Fe
3
O
4
powder. This hybrid composite was dispersed in aqueous medium containing a known amount of potassium perdisulfate (KPS) as oxidant under constant sonication. A known amount of aniline (ANI) was injected in the system which started changing color and ultimately a black mass of (PANI-PNVC-Fe
3
O
4
) separated out. The composite was characterized by FTIR, FESEM and HRTEM analyses. XRD analyses using Williamson-Hall plot revealed average particle size of the PANI-PNVC-Fe
3
O
4
composite to be around 34 nm. HRTEM analyses confirmed the particle size to be in the range 25–40 nm. The dielectric constants of PNVC–Fe
3
O
4
system was low at 0.1–25 kHz whereas the PANI encapsulated PNVC–Fe
3
O
4
nanocomposites showed significantly higher values of dielectric constant (>5500) at 0.1 kHz implying that the interfaces between grain and grain boundary of the composite play a dominant role for enhancing dielectric properties of the system. The ac conductivity was found to be independent of frequency in the range 10
2
–10
3
Hz for all the nanocomposites implying contribution of free charges and rise thereafter appreciably in the frequency range of 1–25 kHz due to trapped charges in the grain boundary.
Journal Article
The Significance of Bioactive Compounds in The Complex Realm of Cardiovascular Complications
Leading cause of morbidity and death globally, Cardiovascular Diseases (CVDs) call for sensible preventive and treatment plans. Recent studies have concentrated on bioactive chemicals originating from natural dietary sources like fruits, vegetables, herbs, and marine resources for their cardioprotective action. Key bioactive substances like flavonoids, polyphenols, omega-3 fatty acids, and phytosterols show notable health advantages by enhancing endothelial function, lowering oxidative stress, controlling inflammation, and so changing lipid metabolism. Notwithstanding encouraging results about their capacity to reduce the risks of hypertension and atherosclerosis, practical application of them still faces difficulties including varied bioavailability, individual response variations, and the necessity of regular dosages. This review emphasizes the need for thorough clinical studies to prove their safety and efficacy as well as the possibilities of bioactive substances as supplementary treatments for improving cardiovascular health.
Journal Article
Exploring the Potential of Traditional Medicinal Plants for Central Nervous System Related Activity
People have used native healing plants in different old-school medicine practices worldwide for hundreds of years to fix all sorts of health problems, including ones that mess with the brain and nerves. As science gets better, folks are getting excited again about checking out what these plants can do for brain and nerve issues like feeling worried or down, seizures, trouble sleeping mixed-up thinking, and brain diseases that get worse over time like forgetting everything, shaking a lot or not being able to control your movements. The brain and nerves are super complicated and coming up with treatments that can change how they work without causing too many problems is one of the biggest headaches in medicine today. That's where these native healing plants come in handy. They're full of natural stuff that might work as safer options or add-ons to regular treatments for brain and nerve problems. A bunch of these plants have active ingredients like alkaloids, flavonoids, terpenoids, glycosides, saponins, polyphenols, and tannins. These ingredients do their thing in different ways, like changing how brain chemicals work (like serotonin, dopamine, GABA glutamate) helping the body fight off damage, cutting down on brain swelling, and helping new brain cells grow. For example, alkaloids like nicotine and caffeine have been known to wake up the brain for a long time, while flavonoids like quercetin and rutin are known to protect brain cells and fight swelling. Certain terpenoids such as those in Cannabis sativa, have a big impact on the central nervous system. Their effects range from pain relief to anxiety reduction. Several native medicinal plants have caught the eye of researchers because of how they affect the central nervous system.
Journal Article
Cricket paralysis virus antagonizes Argonaute 2 to modulate antiviral defense in Drosophila
Some viruses carry suppressors to inhibit host response to infection through the RNAi pathways. Previously the insect virus DCV was found to target host response by inhibiting
Drosophila
Dicer function. The related virus CrPV is now shown to target and inhibit the function of
Drosophila
Argonaute 2 specifically.
Insect viruses have evolved strategies to control the host RNAi antiviral defense mechanism. In nature,
Drosophila melanogaster
C virus (DCV) infection causes low mortality and persistent infection, whereas the closely related cricket paralysis virus (CrPV) causes a lethal infection. We show that these viruses use different strategies to modulate the host RNAi defense machinery. The DCV RNAi suppressor (DCV-1A) binds to long double-stranded RNA and prevents processing by Dicer2. In contrast, the CrPV suppressor (CrPV-1A) interacts with the endonuclease Argonaute 2 (Ago2) and inhibits its activity without affecting the microRNA (miRNA)-Ago1–mediated silencing. We examined the link between viral RNAi suppressors and the outcome of infection using recombinant Sindbis viruses encoding either CrPV-1A or DCV-1A. Flies infected with Sindbis virus expressing CrPV-1A showed a marked increase in virus production, spread and mortality. In contrast, Sindbis pathogenesis was only modestly increased by expression of DCV- 1A. We conclude that RNAi suppressors function as virulence factors in insects and can target the Drosophila RNAi pathway at different points.
Journal Article
Angina pectoris: Revisiting an Age Old Menace
As we know angina pectoris is looming large in USA & other industrialized countries.American Heart Association(AHA) defined angina pectoris as aclinicopathological condition occurred due to transient reversible myocardial ischemia. The curtail causes may be figured ascholesterol deposition in the coronary artery which is also called atherosclerosis and vasoconstriction or vasospasticity of coronary artery.Since, Organic nitrate group of drugs such as Isosorbidedinitrate, Isosorbidemononitrate plays a pivotal role another group of drug that is calcium channel blocker such as Amlodipine, Diltiazemare used for management of angina pectoris. According to American Heart Association (AHA) IHD is defined as a clinicopathological condition due to imbalance between imbalance between oxygen supply to the myocardium & oxygen demand of the myocardium. [...]plaques grow up with the proliferation of fibrous tissues & the surrounding smooth muscle block the artery & reduce blood flow for this reason developed relative ischemia. Since another pivotal point is that platelet is stick on the cholesterol blood flow reduced other nutrients supply also reduced & impaired washout of waste product is reduced for this reason severe ischemia occurs & which is too dangerous rather than stable angina.
Journal Article
Preparation and evaluation of microstructure, dielectric and conductivity (ac/dc) characteristics of a polyaniline/poly N-vinyl carbazole/Fe sub(3)O sub(4) nanocomposite
A poly N-vinyl carbazole- Fe sub(3)O sub(4) hybrid composite was prepared by solid state polymerization of N-vinyl carbazole (NVC) monomer in presence of Fe sub(3)O sub(4) powder. This hybrid composite was dispersed in aqueous medium containing a known amount of potassium perdisulfate (KPS) as oxidant under constant sonication. A known amount of aniline (ANI) was injected in the system which started changing color and ultimately a black mass of (PANI-PNVC-Fe sub(3)O sub(4)) separated out. The composite was characterized by FTIR, FESEM and HRTEM analyses. XRD analyses using Williamson-Hall plot revealed average particle size of the PANI-PNVC-Fe sub(3)O sub(4) composite to be around 34 nm. HRTEM analyses confirmed the particle size to be in the range 25-40 nm. The dielectric constants of PNVC-Fe sub(3)O sub(4) system was low at 0.1-25 kHz whereas the PANI encapsulated PNVC-Fe sub(3)O sub(4) nanocomposites showed significantly higher values of dielectric constant (>5500) at 0.1 kHz implying that the interfaces between grain and grain boundary of the composite play a dominant role for enhancing dielectric properties of the system. The ac conductivity was found to be independent of frequency in the range 10 super(2)-10 super(3) Hz for all the nanocomposites implying contribution of free charges and rise thereafter appreciably in the frequency range of 1-25 kHz due to trapped charges in the grain boundary.
Journal Article
Effect of doping on the electronic properties of Graphene and T-graphene : A theoretical approach
In this communication we present together four distinct techniques for the study of electronic structure of solids : the tight-binding linear muffin-tin orbitals (TB-LMTO), the real space and augmented space recursions and the modified exchange-correlation. Using this we investigate the effect of random vacancies on the electronic properties of the carbon hexagonal allotrope, graphene, and the non-hexagonal allotrope, planar T graphene. We have inserted random vacancies at different concentrations, to simulate disorder in pristine graphene and planar T graphene sheets. The resulting disorder, both on-site (diagonal disorder) as well as in the hopping integrals (off-diagonal disorder), introduces sharp peaks in the vicinity of the Dirac point built up from localized states for both hexagonal and non-hexagonal structures. These peaks become resonances with increasing vacancy concentration. We find that in presence of vacancies, graphene-like linear dispersion appears in planar T graphene and the cross points form a loop in the first Brillouin zone similar to buckled T graphene that originates from \\(\\) and \\(\\)* bands without regular hexagonal symmetry. We also calculate the single-particle relaxation time, \\((q)\\) of \\(q\\) labeled quantum electronic states which originates from scattering due to presence of vacancies, causing quantum level broadening.
Paper