scholarly journals A novel leishmanial copper P-type ATPase plays a vital role in parasite infection and intracellular survival

2021 ◽  
pp. 101539
Author(s):  
Rupam Paul ◽  
Sourav Banerjee ◽  
Samarpita Sen ◽  
Pratiksha Dubey ◽  
Saptarshi Maji ◽  
...  
Keyword(s):  
Intracellular Survival ◽  
Vital Role ◽  
Parasite Infection ◽  
P Type

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

scholarly journals Mitochondrial Transcription Factor A Regulates Mycobacterium bovis–Induced IFN-β Production by Modulating Mitochondrial DNA Replication in Macrophages

2019 ◽  
Author(s):  
Yinjuan Song ◽  
Tariq Hussain ◽  
Jie Wang ◽  
Yi Liao ◽  
Ruichao Yue ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Mycobacterium Bovis ◽  
Intracellular Survival ◽  
Vital Role ◽  
Mitochondrial Transcription ◽  
Host Immune Responses ◽  
Mitochondrial Transcription Factor ◽  
Copy Numbers ◽  
Mitochondrial Transcription Factor A

Abstract Background Mycobacterium bovis persistently survives in macrophages by developing multiple strategies to evade host immune responses, and the early induction of interferon-β (IFN-β) is one of these critical strategies. The mitochondrial transcription factor A (TFAM) plays a vital role in mitochondrial DNA (mtDNA) metabolism and has been suggested to influence IFN-β production in response to viral infection. However, its role in the production of IFN-β by M. bovis has not been elucidated. Methods In the current study, we investigated the role of TFAM in the production of IFN-β in M. bovis–infected macrophages. Results We found that knockdown of TFAM expression significantly reduced M. bovis–induced IFN-β production, mtDNA copy numbers and cytosolic mtDNA were increased in murine macrophages with M. bovis infection, cytosolic mtDNA contributed to IFN-β production, and TFAM was required for the increase in mtDNA copy numbers induced by M. bovis. We also observed that TFAM affected the intracellular survival of M. bovis. Conclusions Our results suggest that TFAM plays an essential role in M. bovis–induced IFN-β production by regulating mtDNA copy numbers. This might be a new strategy adopted by M. bovis for its intracellular survival.

Photovoltaic and photoelectrochemical conversion of solar energy

2007 ◽  
Author(s):  
Michael Grätzel
Keyword(s):  
Solar Energy ◽  
Electric Field ◽  
Vital Role ◽  
Pure Silicon ◽  
Doped Silicon ◽  
Sustainable Energy Systems ◽  
Present Rate ◽  
Set Up ◽  
P Type ◽  
Minority Carriers

The Sun provides about 100,000 Terawatts (TW) to the Earth, which is approximately ten thousand times greater than the world’s present rate of energy consumption (14 TW). Photovoltaic (PV) cells are being used increasingly to tap into this huge resource and will play a key role in future sustainable energy systems. Indeed, our present needs could be met by covering 0.5% of the Earth’s surface with PV installations that achieve a conversion efficiency of 10%. Fig. 8.1 shows a simple diagram of how a conventional photovoltaic device works. The top and bottom layers are made of an n-doped and p-doped silicon, where the charge of the mobile carriers is negative (electrons) or positive (holes), respectively. The p-doped silicon is made by ‘doping’ traces of an electron-poor element such as gallium into pure silicon, whereas n-doped silicon is made by doping with an electron-rich element such as phosphorus. When the two materials contact each other spontaneous electron and hole transfer across the junction produces an excess positive charge on the side of the n-doped silicon (A) and an excess negative charge on the opposite p-doped (B) side. The resulting electric field plays a vital role in the photovoltaic energy conversion process. Absorption of sunlight generates electron-hole pairs by promoting electrons from the valence band to the conduction band of the silicon. Electrons are minority carriers in the p-type silicon while holes are minority carriers in the n-type material. Their lifetime is very short as they recombine within microseconds with the oppositely charged majority carriers. The electric field helps to collect the photo-induced carriers because it attracts the minority carriers across the junction as indicated by the arrows in Fig. 8.1, generating a net photocurrent. As there is no photocurrent flowing in the absence of a field, the maximum photo-voltage that can be attained by the device equals the potential difference that is set up in the dark at the p-n junction. For silicon this is about 0.7V. So far, solid-state junction devices based on crystalline or amorphous silicon (Si) have dominated photovoltaic solar energy converters, with 94% of the market share.

The novel leishmanial Copper P-type ATPase plays a vital role in intracellular parasite survival

2021 ◽  
Author(s):  
Rupam Paul ◽  
Sourav Banerjee ◽  
Samarpita Sen ◽  
Pratiksha Dubey ◽  
Anand K Bachhawat ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Life Forms ◽  
Vital Role ◽  
Copper Stress ◽  
The Novel ◽  
Free Living ◽  
Parasite Survival ◽  
Cellular Copper ◽  
P Type ◽  
Golgi Network

AbstractCopper is essential for all life forms; however in excess it is extremely toxic. Toxic properties of copper are utilized by hosts against various pathogenic invasions. Leishmania, in its both free-living and intracellular forms was found to exhibit appreciable tolerance towards copper-stress. To determine the mechanism of copper-stress evasion employed by Leishmania we identified and characterized the hitherto unknown Copper-ATPase in Leishmania major and determined its role in parasite’s survival in host macrophage cells. L. major Cu-ATPase, LmATP7, exhibits high homology with its orthologues at multiple conserved motifs. In promastigotes, LmATP7 localized to the plasma membrane with a fraction in intracellular puncta. Upon copper treatment, LmATP7 expression increases few folds. LmATP7 is capable of complementing copper transport in Cu-ATPase-Δ yeast strain. Promastigotes overexpressing LmATP7 exhibits higher survival upon copper stress indicating efficacious copper export compared to wild type parasites. We explored macrophage-Leishmanial interaction with respect to copper stress subjected by the host upon parasite and the parasite’s reciprocating response thereon to evade the stress. The Copper-P-type-ATPases ATP7A/7B serves as major copper exporter in eukaryotes that maintain cellular copper levels. We found that Leishmania infection, triggers ATP7A upregulation in macrophages. Additionally, as part of host response, ATP7A traffics from trans-Golgi network and transports copper to the endosomal and endolysosomal compartments harbouring the Leishmania amastigotes. Finally, we show LmATP7 overexpression in this parasite, increased amastigote survivability within infected macrophages, establishing its role in combating host-induced copper stress.

scholarly journals An Algebraic Approach to Find Some Topological Indices of Derived Graphs of the Benzene Ring

2021 ◽  
Vol 12 (4) ◽  
pp. 5431-5443
Keyword(s):  
Benzene Ring ◽  
Line Graph ◽  
Algebraic Approach ◽  
Chemical Compounds ◽  
Vital Role ◽  
Topological Indices ◽  
Zagreb Index ◽  
Subdivision Graph ◽  
Surface Network ◽  
P Type

Topological indices play a vital role in understanding the chemical and structural properties of the chemical compounds and nanostructures. By finding the M-polynomial of a graph representing a chemical compound, one can obtain the closed forms of some of the commonly known degree-based topological indices of the compound, such as the Zagreb index, general Randic ́ Index and harmonic index. In this article, we obtain the expression for the M-polynomial of the derived graphs of the Benzene ring embedded in the P-type surface network in 2D, namely the line graph, the subdivision graph, and the line graph of its subdivision. Furthermore, some of the degree-based topological indices are obtained for these graphs using their M-polynomials.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Interface morphology of thermal oxide grown on polycrystalline silicon by different processes

1992 ◽  
Vol 50 (2) ◽  
pp. 1396-1397
Author(s):  
H. Yen ◽  
E. P. Kvam ◽  
R. Bashir ◽  
S. Venkatesan ◽  
G. W. Neudeck
Keyword(s):  
Integrated Circuits ◽  
Polycrystalline Silicon ◽  
Silicon Films ◽  
Interface Morphology ◽  
Oxide Interface ◽  
Poly Silicon ◽  
Thermal Oxide ◽  
Grain Orientations ◽  
Polycrystalline Silicon Films ◽  
P Type

Polycrystalline silicon, when highly doped, is commonly used in microelectronics applications such as gates and interconnects. The packing density of integrated circuits can be enhanced by fabricating multilevel polycrystalline silicon films separated by insulating SiO2 layers. It has been found that device performance and electrical properties are strongly affected by the interface morphology between polycrystalline silicon and SiO2. As a thermal oxide layer is grown, the poly silicon is consumed, and there is a volume expansion of the oxide relative to the atomic silicon. Roughness at the poly silicon/thermal oxide interface can be severely deleterious due to stresses induced by the volume change during oxidation. Further, grain orientations and grain boundaries may alter oxidation kinetics, which will also affect roughness, and thus stress.Three groups of polycrystalline silicon films were deposited by LPCVD after growing thermal oxide on p-type wafers. The films were doped with phosphorus or arsenic by three different methods.

Determination of arsenic atom distribution arsenic doped silicon using HOLZ-line analysis

1996 ◽  
Vol 54 ◽  
pp. 976-977
Author(s):  
Y. Kikuchi ◽  
N. Hashikawa ◽  
F. Uesugi ◽  
E. Wakai ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Zone Axis ◽  
Experimental Result ◽  
Background Intensity ◽  
Crystal Thickness ◽  
Arsenic Atom ◽  
Doped Silicon ◽  
P Type ◽  
Line Analysis

In order to measure the concentration of arsenic atoms in nanometer regions of arsenic doped silicon, the HOLZ analysis is carried out underthe exact [011] zone axis observation. In previous papers, it is revealed that the position of two bright lines in the outer SOLZ structures on the[011] zone axis is little influenced by the crystal thickness and the background intensity caused by inelastic scattering electrons, but is sensitive to the concentration of As atoms substitutbnal for Siatomic site.As the result, it becomes possible to determine the concentration of electrically activated As atoms in silicon within an observed area by means of the simple fitting between experimental result and dynamical simulatioan. In the present work, in order to investigate the distribution of electrically activated As in silicon, the outer HOLZ analysis is applied using a nanometer sized probe of TEM equipped with a FEG.Czodiralsld-gown<100>orientated p-type Si wafers with a resistivity of 10 Ώ cm are used for the experiments.TheAs+ implantation is performed at a dose of 5.0X1015cm-2at 25keV.

Three-Dimensional reconstruction of isolated centrosomes by automated electron tomography

1994 ◽  
Vol 52 ◽  
pp. 310-311
Author(s):  
M.B. Braunfeld ◽  
M. Moritz ◽  
B.M. Alberts ◽  
J.W. Sedat ◽  
D.A. Agard
Keyword(s):  
Electron Tomography ◽  
Three Dimensional ◽  
Vital Role ◽  
Complex Nature ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
Nucleation Sites ◽  
Dimensional Reconstruction ◽  
Organizing Center ◽  
Resolution Model

In animal cells, the centrosome functions as the primary microtubule organizing center (MTOC). As such the centrosome plays a vital role in determining a cell's shape, migration, and perhaps most importantly, its division. Despite the obvious importance of this organelle little is known about centrosomal regulation, duplication, or how it nucleates microtubules. Furthermore, no high resolution model for centrosomal structure exists.We have used automated electron tomography, and reconstruction techniques in an attempt to better understand the complex nature of the centrosome. Additionally we hope to identify nucleation sites for microtubule growth.Centrosomes were isolated from early Drosophila embryos. Briefly, after large organelles and debris from homogenized embryos were pelleted, the resulting supernatant was separated on a sucrose velocity gradient. Fractions were collected and assayed for centrosome-mediated microtubule -nucleating activity by incubating with fluorescently-labeled tubulin subunits. The resulting microtubule asters were then spun onto coverslips and viewed by fluorescence microscopy.

Investigating the functional link between TMEM165 and SPCA1

2019 ◽  
Vol 476 (21) ◽  
pp. 3281-3293 ◽  
Author(s):  
Elodie Lebredonchel ◽  
Marine Houdou ◽  
Hans-Heinrich Hoffmann ◽  
Kateryna Kondratska ◽  
Marie-Ange Krzewinski ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Complete Loss ◽  
Protein Family ◽  
Uncharacterized Protein ◽  
Functional Link ◽  
P Type

TMEM165 was highlighted in 2012 as the first member of the Uncharacterized Protein Family 0016 (UPF0016) related to human glycosylation diseases. Defects in TMEM165 are associated with strong Golgi glycosylation abnormalities. Our previous work has shown that TMEM165 rapidly degrades with supraphysiological manganese supplementation. In this paper, we establish a functional link between TMEM165 and SPCA1, the Golgi Ca2+/Mn2+ P-type ATPase pump. A nearly complete loss of TMEM165 was observed in SPCA1-deficient Hap1 cells. We demonstrate that TMEM165 was constitutively degraded in lysosomes in the absence of SPCA1. Complementation studies showed that TMEM165 abundance was directly dependent on SPCA1's function and more specifically its capacity to pump Mn2+ from the cytosol into the Golgi lumen. Among SPCA1 mutants that differentially impair Mn2+ and Ca2+ transport, only the Q747A mutant that favors Mn2+ pumping rescues the abundance and Golgi subcellular localization of TMEM165. Interestingly, the overexpression of SERCA2b also rescues the expression of TMEM165. Finally, this paper highlights that TMEM165 expression is linked to the function of SPCA1.

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