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91.
Leslie A. Lewis Nidhi Gadura Marsha Greene Robert Saby Nigel D. F. Grindley 《Molecular microbiology》2001,42(4):887-901
In the first step of IS2 transposition, the formation of an IS2 minicircle, the roles of the two IS ends differ. Terminal cleavage initiates exclusively at the right inverted repeat (IRR) - the donor end - whereas IRL is always the target. At the resulting minicircle junction, the two abutted ends are separated by a spacer of 1 or 2 basepairs. In this study, we have identified the determinants of donor and target function. The inability of IRL to act as a donor results largely from two sequence differences between IRL and IRR - an extra basepair between the conserved transposase binding sequences and the end of the element, and a change of the terminal dinucleotide from CA-3' to TA-3'. These two changes also impose a characteristic size on the minicircle junction spacer. The only sequences required for the efficient target function of IRL appear to be contained within the segment from position 11-42. Although IRR can function as a target, its shorter length and additional contacts with transposase (positions 1-7) result in minicircles with longer, and inappropriate, spacers. We propose a model for the synaptic complex in which the terminus of IRL makes different contacts with the transposase for the initial and final strand transfer steps. The sequence differences between IRR and IRL, and the behavioural characteristics of IRL that result from them, have probably been selected because they optimize expression of transposase from the minicircle junction promoter, Pjunc. 相似文献
92.
Nidhi Batra Manuel A. Riquelme Sirisha Burra Rekha Kar Sumin Gu Jean X. Jiang 《The Journal of biological chemistry》2014,289(15):10582-10591
Connexin (Cx) 43 hemichannels in osteocytes are thought to play a critical role in releasing bone modulators in response to mechanical loading, a process important for bone formation and remodeling. However, the underlying mechanism that regulates the opening of mechanosensitive hemichannels is largely unknown. We have recently shown that Cx43 and integrin α5 interact directly with each other, and activation of PI3K appears to be required for Cx43 hemichannel opening by mechanical stimulation. Here, we show that mechanical loading through fluid flow shear stress (FFSS) increased the level of active AKT, a downstream effector of PI3K, which is correlated with the opening of hemichannels. Both Cx43 and integrin α5 are directly phosphorylated by AKT. Inhibition of AKT activation significantly reduced FFSS-induced opening of hemichannels and disrupted the interaction between Cx43 and integrin α5. Moreover, AKT phosphorylation on Cx43 and integrin α5 enhanced their interaction. In contrast to the C terminus of wild-type Cx43, overexpression of the C-terminal mutant containing S373A, a consensus site previously shown to be phosphorylated by AKT, failed to bind with α5 and hence could not inhibit hemichannel opening. Together, our results suggest that AKT activated by FFSS directly phosphorylates Cx43 and integrin α5, and Ser-373 of Cx43 plays a predominant role in mediating the interaction between these two proteins and Cx43 hemichannel opening, a crucial step to mediate the anabolic function of mechanical loading in the bone. 相似文献
93.
The effects of fluoride on the photosynthetic electron transport chain have been studied in spinach thylakoid membranes. Inhibition
in photosystem (PS) 2 electron transport rates and a subsequent increase in PS 1 electron transport rate indicated a possibility
of state transitions being a mechanism of fluoride action. This hypothesis was further confirmed by the increase in fluorescence
emission F735/685 at 77 K, a decrease in variable to maximum fluorescence ratio (Fv/Fm) at room temperature and increase in the absorption cross section of PS 1 suggesting that fluoride affects distribution of
the excitation energy in favour of PS 1 at the expense of PS 2. 相似文献
94.
We report the occurrence of a freshwater medusa from a laboratory aquarium in Ranchi, Bihar, India. The consistent emergence of these medussae coincided with sunny days after heavy and prolonged rainfall in the months of August to October. The material showed similarity with Limnocnide indica Annandale and L. nepalensis Dumont but differed in many respects, and is given the status of a distinct species, Limnocnida biharensis n.sp.Author to whom all correspondence should be addressed.Author to whom all correspondence should be addressed. 相似文献
95.
Marc Kschonsak Lionel Rougé Christopher P. Arthur Ho Hoangdung Nidhi Patel Ingrid Kim Matthew C. Johnson Edward Kraft Alexis L. Rohou Avinash Gill Nadia Martinez-Martin Jian Payandeh Claudio Ciferri 《Cell》2021,184(5):1232-1244.e16
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96.
This study was designed for investigating the effect of Asparagus racemosus (AR) extract and chitosan (CTN) in facilitating the permeation of carvedilol (CDL) across rat epidermis. Transdermal flux
of carvedilol through heat-separated rat epidermis was investigated in vitro using vertical Keshary–Chien diffusion cells. Biophysical and microscopic manifestations of epidermis treated with AR extract,
CTN, and AR extract–CTN mixture were investigated by using differential scanning calorimetry, transepidermal water loss, scanning
electron microscopy (SEM), and transmission electron microscopy (TEM). Biochemical estimations of cholesterol, sphingosine,
and triglycerides were carried out for treated excised as well as viable rat epidermis. The antihypertensive activity of the
patches in comparison with that of oral carvedilol was studied in deoxycorticosterone acetate-induced hypertensive rats. The
permeation of carvedilol across excised rat epidermis was significantly higher (p < 0.05) when AR extract, CTN, or AR extract–CTN mixture was used as donor vehicle as compared to propylene glycol/ethanol
(7:3) mixture. Epidermis obtained after 12 h treatment of viable rat skin with AR extract–CTN mixture showed significantly
higher (p < 0.05) permeability to CDL as compared to that after treatment with AR extract or CTN alone. Further, the application of
patches containing AR extract–CTN mixture resulted in sustained release of CDL which was able to control the hypertension
in deoxycorticosterone acetate-induced hypertensive rats through 36 h. Estimation of micro constituents in rat epidermis revealed
maximum extraction of cholesterol, sphingosine, and triglycerides after treatment with AR extract–CTN mixture. This was manifested
in altered lipid and protein-specific thermotropic transitions. Further, increase in intercellular space, disordered lipid
structure, and corneocyte detachment as observed in SEM and TEM suggested great potential of AR extract for use as percutaneous
permeation enhancer. The developed transdermal patches of CDL containing AR extract–CTN mixture exhibited better performance
as compared to oral administration in controlling hypertension in rats. 相似文献
97.
Mayank Mittal Sanjay Kumar Biswas Vandana Singh Nidhi Arela Vishwa Mohan Katoch Ram Das Virendra Singh Yadav Bharat Bajaj Keshar Kunja Mohanty 《Molecular biology reports》2018,45(4):469-476
Tuberculosis (TB) is a disease of global importance. There is an increasing recognition of the role of Toll like receptors, important pattern recognition receptors of host immune system, in determining the susceptibility or resistance to TB in various populations. In an attempt to examine the importance of Toll like receptors in immune response to Mycobacterium tuberculosis infection, we explored two variants each of TLR2 and TLR9 in a population residing in Uttar Pradesh, India. Genotyping was performed to detect -196 to -174 del polymorphism and G2258A SNP (Arg753Gln, rs5743708) in TLR2 gene and -T1237C (rs5743836) and G2848A (rs352140) SNP in TLR9 gene in patients with pulmonary TB and healthy controls. The A allele of G2848A SNP in TLR9 gene was found with a marginally higher frequency among TB patients as compared to healthy controls, suggesting that A allele at position 2848 of TLR9 gene may be associated with susceptibility to TB in North Indian population [p?=?0.05, Mantel–Haenszel OR?=?1.34, 95% CI (1.0–1.82)]. 相似文献
98.
Helen Louise May-Simera Qin Wan Balendu Shekhar Jha Juliet Hartford Vladimir Khristov Roba Dejene Justin Chang Sarita Patnaik Quanlong Lu Poulomi Banerjee Jason Silver Christine Insinna-Kettenhofen Dishita Patel Mostafa Lotfi May Malicdan Nathan Hotaling Arvydas Maminishkis Rupa Sridharan Kapil Bharti 《Cell reports》2018,22(1):189-205
99.
Federica Calì Sanjay Kumar Bharti Roberta Di Perna Robert M. Brosh Jr Francesca M. Pisani 《Nucleic acids research》2016,44(2):705-717
We present evidence that Tim establishes a physical and functional interaction with DDX11, a super-family 2 iron-sulfur cluster DNA helicase genetically linked to the chromosomal instability disorder Warsaw breakage syndrome. Tim stimulates DDX11 unwinding activity on forked DNA substrates up to 10-fold and on bimolecular anti-parallel G-quadruplex DNA structures and three-stranded D-loop approximately 4–5-fold. Electrophoretic mobility shift assays revealed that Tim enhances DDX11 binding to DNA, suggesting that the observed stimulation derives from an improved ability of DDX11 to interact with the nucleic acid substrate. Surface plasmon resonance measurements indicate that DDX11 directly interacts with Tim. DNA fiber track assays with HeLa cells exposed to hydroxyurea demonstrated that Tim or DDX11 depletion significantly reduced replication fork progression compared to control cells; whereas no additive effect was observed by co-depletion of both proteins. Moreover, Tim and DDX11 are epistatic in promoting efficient resumption of stalled DNA replication forks in hydroxyurea-treated cells. This is consistent with the finding that association of the two endogenous proteins in the cell extract chromatin fraction is considerably increased following hydroxyurea exposure. Overall, our studies provide evidence that Tim and DDX11 physically and functionally interact and act in concert to preserve replication fork progression in perturbed conditions. 相似文献
100.
Bharti P. Bawanthade Ashok A. Mistry Nilesh Ugemuge Isha S. Chaudari Sanjay J. Dhoble 《Luminescence》2024,39(4):e4736
In recent trends, radiation falls under the narrowband ultraviolet-B region (305–315 nm) widely used in phototherapy lamp applications in the treatment of skin diseases. In this paper, we report a Gd3+-doped NaYF4 luminescent material synthesized for the first time using the low-temperature co-precipitation method. It crystallized into a face-centred cubic structure, as confirmed by X-ray diffraction characterization techniques and Rietveld refinement. The photoluminescence property of the as-prepared sample shows a highly intense, sharp emission band obtained at 311 nm, which belongs to the narrowband ultraviolet-B region and corresponds to the transition of the 6P7/2→8S7/2 level of the Gd3+ ions under 272 nm excitation (8S7/2 to 6IJ). The transitions of the Gd3+ ions are detected entirely with different concentrations of Gd3+ ions. Scanning electron microscopy analysis indicated that the average particle was 288 nm. The critical distance for energy transfer was calculated to be equal to 11.5017 Å. Dipole–dipole interaction is responsible for energy transfer, as analyzed by Dexter theory. These excellent optical characteristics, together with their highly efficient and low-cost synthesis approach, indicate that synthesized NaYF4:Gd3+ phosphors have excessive potential for phototherapeutic lamp applications. 相似文献