Effect of knocking down the insulin receptor on mouse rod responses.

Previous experiments have shown that the insulin receptor (IR) is expressed in mammalian rods and contributes to the protection of photoreceptors during bright-light exposure. The role of the insulin receptor in the production of the light response is however unknown. We have used suction-electrode recording to examine the responses of rods after conditionally knocking down the insulin receptor. Our results show that these IR knock-down rods have an accelerated decay of the light response and a small decrease in sensitivity by comparison to littermate WT rods. Our results indicate that the insulin receptor may have some role in controlling the rate of rod response decay, but they exclude a major role of the insulin receptor pathway in phototransduction

Protein tyrosine phosphatase-1B regulates the tyrosine phosphorylation of the adapter Grb2-associated binder 1 (Gab1) in the retina

Abstract Background Gab1 (Grb2-associated binder 1) is a key coordinator that belongs to the insulin receptor substrate-1 like family of adaptor molecules and is tyrosine phosphorylated in response to various growth factors, cytokines, and numerous other molecules. Tyrosine phosphorylated Gab1 is able to recruit a number of signaling effectors including PI3K, SHP2 and PLC-γ. In this study, we characterized the localization and regulation of tyrosine phosphorylation of Gab1 in the retina. Results Our immuno localization studies suggest that Gab1 is expressed in rod photoreceptor inner segments. We found that hydrogen peroxide activates the tyrosine phosphorylation of Gab1 ex vivo and hydrogen peroxide has been shown to inhibit the protein tyrosine phosphatase PTP1B activity. We found a stable association between the D181A substrate trap mutant of PTP1B and Gab1. Our studies suggest that PTP1B interacts with Gab1 through Tyrosine 83 and this residue may be the major PTP1B target residue on Gab1. We also found that Gab1 undergoes a light-dependent tyrosine phosphorylation and PTP1B regulates the phosphorylation state of Gab1. Consistent with these observations, we found an enhanced Gab1 tyrosine phosphorylation in PTP1B deficient mice and also in retinas treated ex vivo with a PTP1B specific allosteric inhibitor. Conclusions Our laboratory has previously reported that retinas deficient of PTP1B are resistant to light damage compared to wild type mice. Since Gab1 is negatively regulated by PTP1B, a part of the retinal neuroprotective effect we have observed previously in PTP1B deficient mice could be contributed by Gab1 as well. In summary, our data suggest that PTP1B regulates the phosphorylation state of retinal Gab1 in vivo

VIRTUAL LEARNING ENVIRONMENT IS PLEASURE OR PRESSURE

The primary aim of this study intends the perception of students towards online learning in the covid-19 pandemic period. The pandemic has changed the traditional concepts of the education system and broken the functions of the educational institutions. But, they give it an opportunity to change pedagogy. The research paper discussed the students’ opinions on online learning/virtual classroom learning. This study applied a qualitative approach and prepared a systematic questionnaire for data collection. The researcher collected the data from 258 students from different places in India and also, the disproportionate sampling used for data collection. The research mainly focused on the student’s perception, the comfort and discomfort of e-learning, using electronic devices for communication, the virtual learning is a pleasure or pressure to the students, the digital skills of the students and their active performance. The study revealed that over 50% of the students are having excellent knowledge of digital skills. The students are attending online classes through their personal computers or laptops and phones. The teachers are allowing the students to ask questions and clear the doubt of the students. The study found that the students are losing social interaction with teachers, friends and cannot access the library because of online classes. Finally, the students felt that online learning is a pressure instead of pleasure

Phosphoinositides: Minor Lipids Make a Major Impact on Photoreceptor Cell Functions

Activation of the phosphoinositide (PI) cycle generates the second messengers that control various aspects of cellular signaling. We have previously shown that two PI cycle enzymes, type II phosphatidylinositol 5-phosphate 4-kinase (PIPK IIα) and phosphoinositide 3-kinase (PI3K), are activated through light stimulation. In our earlier studies, we measured enzyme activities, instead of directly measuring the products, due to lack of sensitive analytical techniques. Cells have very low levels of PIs, compared to other lipids, so special techniques and sensitive analytical instruments are necessary for their identification and quantification. There are also other considerations, such as different responses in different cell types, which may complicate quantification of PIs. For example, although light activated PIPK IIα, there was no increase in PI-4,5-P2 measured by liquid chromatography-mass spectrometry (LC/MS) This discrepancy is due to the heterogeneous nature of the retina, which is composed of various cell types. In this study, we examined PI generation in situ using immunohistochemistry with specific PI antibodies. PIs were generated in specific retinal cell layers, suggesting that analyzing PIs from the total retina by LC/MS underscores the significance. This suggests that PI-specific antibodies are useful tools to study the cell-specific regulation of PIs in the retina

E-Resource Management and Management Issues and Challenges

E-resources are inevitable, technology has grown and libraries are also adopting the technologies although adopting have many challenges to the library professionals. Whenever something new comes they need to update themselves. A study investigated E-Resources management and management issues of Indian library professional perspectives. For this study, data was collected from various academic institutes/university libraries in India. It includes institutes of national importance, central, state, deemed and private universities. The study finds that the majority of the libraries subscribed to E-journals and E-books, administration related challenges faced by LIS professionals. The t-test results revealed a lack of professional skills is the reason for issues and challenges of Library management

Imidazolium-based titanosilicate nanospheres as active catalysts in carbon dioxide conversion:Towards a cascade reaction from alkenes to cyclic carbonates

Porous silica-based nanospheres bearing titanium centres as single site were successfully synthesized employing a time- and energy-efficient procedure. The influence of the post-synthesis treatment on the insertion of Ti was investigated via DR UV-Vis and XPS spectroscopy and the titanium content was quantified through ICP-OES analysis. The textural and structural properties of the different solids were evaluated via XRD, TEM and N2 physisorption. The resulting materials were thereafter covalently functionalized with imidazolium chloride, followed by characterization via 29Si and 13C solid-state NMR, N2 physisorption and chemical combustion analysis. The bi-functional catalysts were tested in the challenging conversion of CO2 with cyclohexene oxide to the corresponding cyclic carbonate as well as with various other epoxides with excellent results. The insertion of Ti as single site played a key role substantially improving the activity of the solids. The most active bi-functional material was successfully recovered and reused through multiple cycle without loss of the catalytic activity. Moreover, the cyclohexene epoxidation reaction was tested as well employing the mono-functionalized Ti-based material. The catalytic mixture, composed by the mono-functional and bi-functional solids, was efficiently used to convert the cyclohexene into cyclohexene oxide and subsequently the cyclohexene oxide into the corresponding carbonate thus opening the prospect for a cascade reaction

Improving Localization Ratio in Wireless Sensor Networks using Efficient Path Planning

Localization is one of the challenging area in wireless sensor networks (WSNs), since it requires to maintain an association between the sensed data and corresponding events also it provides fundamental support for many location-aware protocols and applications. Location can also be computed by equipping each node with global positioning system (GPS), but constraints on maintenance and cost of GPS make it infeasible especially for large networks. A approach is to use of mobile anchor nodes, which are equipped with GPS units moving among unknown nodes and periodically broadcast their current locations to help nearby unknown nodes with localization. This method not only reduces the cost of WSNs but also covers more area as compared to static anchor node. In this case, an important issues for localization involves the path planning of anchor node. In this work, we propose a new path planning algorithm and apply on DV-hop localization with the aim of reducing co-linearity and maximizing number of localized nodes. We also implement some of the existing path planning algorithms such as SCAN, LMAT and apply on DV-hop localization algorithm.Simulations are performed using NS-2 simulator. Performance of proposed algorithm shows improvement as compared to existing path planning algorithms in terms of localization ratio

E-Resource Management and Management Issues and Challenges

E-resources are inevitable, technology has grown and libraries are also adopting the technologies although adopting have many challenges to the library professionals. Whenever something new comes they need to update themselves. A study investigated E-Resources management and management issues of Indian library professional perspectives. For this study, data was collected from various academic institutes/university libraries in India. It includes institutes of national importance, central, state, deemed and private universities. The study finds that the majority of the libraries subscribed to E-journals and E-books, administration related challenges faced by LIS professionals. The t-test results revealed a lack of professional skills is the reason for issues and challenges of Library management

Lipid Nanoparticles for Ocular Gene Delivery

Lipids contain hydrocarbons and are the building blocks of cells. Lipids can naturally form themselves into nano-films and nano-structures, micelles, reverse micelles, and liposomes. Micelles or reverse micelles are monolayer structures, whereas liposomes are bilayer structures. Liposomes have been recognized as carriers for drug delivery. Solid lipid nanoparticles and lipoplex (liposome-polycation-DNA complex), also called lipid nanoparticles, are currently used to deliver drugs and genes to ocular tissues. A solid lipid nanoparticle (SLN) is typically spherical, and possesses a solid lipid core matrix that can solubilize lipophilic molecules. The lipid nanoparticle, called the liposome protamine/DNA lipoplex (LPD), is electrostatically assembled from cationic liposomes and an anionic protamine-DNA complex. The LPD nanoparticles contain a highly condensed DNA core surrounded by lipid bilayers. SLNs are extensively used to deliver drugs to the cornea. LPD nanoparticles are used to target the retina. Age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy are the most common retinal diseases in humans. There have also been promising results achieved recently with LPD nanoparticles to deliver functional genes and micro RNA to treat retinal diseases. Here, we review recent advances in ocular drug and gene delivery employing lipid nanoparticles