Identifying a C-terminal ATP binding sites-based novel Hsp90-Inhibitor in silico: A plausible therapeutic approach in Alzheimer’s disease

Background

Alzheimer’s disease (AD) is a progressive brain disorder, which gradually and irreversibly destroys the intellectual and cognitive abilities of the brain. Heat shock protein 90 (Hsp90α) is a molecular chaperone which was found to regulate the function of number of client proteins including tau that is involved in the cause of the AD. Inhibition of Hsp90α by C-Terminal domain (CTD) ATP binding-site blockage might be used as an effective treatment strategy against the disease via degradation of tau proteins that are involved in the progression of the disease. Till date, a variety of drugs have been identified as Hsp90α inhibitors, which include Novobiocin, Clorobiocin, Epigallocatechingallate (EGCG) and Derrubone. However, which drug among the four binds to the CTD ATP binding site strongly and what are the specific residue responsible for such binding, have not been reported so far.

Hypothesis

We hypothesize that binding site for ATP of Hsp90α CTD contains multiple ATP binding sites. We also hypothesize that a drug which can bind to the ATP binding site of CTD strongly can inhibit Hsp90α function which is in turn redirects towards the proteasomal degradation of diseased client protein like tau in AD. Such inhibition will find a novel therapeutic approach in the treatment of AD.

Experimental design

The identification of ATP binding site of Hsp90α CTD was done using various software tools like Hex 6.3, CastP, protein Hydrophobicity plots, ATPint and LigPlot+ v.1.4.5. Docking experiments were conducted between Hsp90αCTD and its inhibitors at these ATP binding site using the Autodock 4.0. The docking energies were further compared to obtain the most effective Hsp90α inhibitor of CTD.

Results

From our experiments, Leucine (Leu) 665, Leu 666 and Leu 694 were predicted to be located in CTD ATP binding site. Furthermore, docking studies were performed of various Hsp90α inhibitors like Novobiocin, Clorobiocin, Epigallocatechingallate (EGCG) and Derrubone with the previously recognized ATP binding residues of CTD i.e. Leu 665, Leu 666 and Leu 694. The docking results of Derrubone showed the highest binding energy at all the three sites of ATP interaction. Additionally, Derrubone showed the best binding energy at Leu 666 (−7.53 kcal/mol) compared to Leu 665 (−7.20 kcal/mol) and Leu 694 (−6.67 kcal/mol).

Conclusion

Based on our findings, we propose that the recognized sites i.e. Leu665, Leu 666 and Leu694 could possibly be the binding sites of Hsp90α CTD for ATP and the Hsp90 inhibitors. It was predicted that Derrubone could bind with CTD of Hsp90α strongly and resulted tau protein degradation which might be considered to be a therapeutic approach in AD.     

A comparison of the presence of Theileria ovis by PCR amplification of their SSU rRNA gene in small ruminants from two provinces of Pakistan

ObjectiveTo compare the presence of Theileria ovis in small ruminants from two provinces of Pakistan and to determine the risk factors associated with the spread of theileriosis.MethodsIn present study, a total of 210 blood samples were collected from sheep (n=99) and goats (n=111) from 5 sampling sites in Punjab (Dera Ghazi Khan, Layyah, Multan and Rahim Yar Khan districts) and Khyber Pukhtoon Khwa (district Kohat) provinces, in Pakistan, from randomly selected herds. Data on the characteristics of the animals (species, gender, age, tick presence or absence, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) was collected through questionnaires.ResultsTwelve blood samples (6% of total), 11 from district Kohat, produced the 520 base pairs DNA fragment specific for small subunit ribosomal RNA (ssu rRNA) gene of Theileria ovis, by PCR amplification, of which 11 were sheep and 1 was goat indicating that sheep are more significantly (P=0.001) prone to this parasite. On the other hand parasite was detected only in 2 out of 210 samples (1%) by blood smear screening confirming PCR as the reliable detection tool.ConclusionsPCR is more sensitive and reliable diagnostic tool for detection of Theileria sp. as compared to blood smear screening. Incidence of Theileria ovis is very high in Khyber Pukhtoon Khwa as compared to Punjab province. It was also observed that presence of ticks on animals was the only significant risk factor associated with the theileriosis in small ruminants.     

Green dyeing of modified cotton fabric with Acalypha wilkesiana leave extracts

Over the last few decades, a number of natural dyes have become non-toxic, eco-friendly and biocompatible substitutes of highly carcinogenic synthetic dyes. Herein, we selected the Acalypha wilkesiana (copper plant) as the source of a natural colorant for auxiliary-free dyeing of cotton, a way forward to eco-friendly dyeing. The bioactive phytochemical constituents of this plant include tannins, flavonoids, phlobatanins, cardiac glycosides, saponins, alkaloids, terpenes and steroids. Both the aqueous and methanol extracts of copper leaf were extracted and applied to unmodified and modified cotton fabrics with the percentage shade depths of 0.5%, 1%, 2%, 4%, 5% and 6% both at pH 4 and 7. The cationized samples rendered substantial improvement in color strength (K/S) values as compared to un-cationized ones. Aqueous and methanolic extracts offered very similar K/S values on cationized samples. Without using any metallic salts as mordants, the color fastness properties like rubbing fastness, washing fastness were also slightly improved due to greater dye fixation on cationized samples compared to uncationized ones. In conclusion, the aqueous extract exhibited dye fixation and color fastness properties comparable to methanolic extract at pH 4 and 7. Thus, it suggested the avoidance of toxic organic solvent for extraction and auxiliary chemicals in subsequent dyeing, a step towards eco-friendly sustainable dyeing.     

Aggregation induced emission based fluorenes as dual-channel fluorescent probes for rapid detection of cyanide: applications of smartphones and logic gates

Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes. Based on this principle, fluorescent probes (1a–c) were synthesized, and they displayed excellent aggregation induced emission (AIE) behavior in a H₂O/DMF (4 : 1, v/v) mixture due to restrictions in intramolecular charge transfer (ICT). As a comparison, probe 1d was synthesized by installing an electron withdrawing (–NO₂) group that surprisingly quenched the aggregation behaviour. Additionally, AIE active probes 1a–c displayed a highly sensitive dual channel (fluorometric and colorimetric) response towards rapid detection of CN⁻, which is an active toxic material. Probes 1a–c showed selectively enhanced fluorescence emission behavior towards CN⁻ with detection limits of 1.34 ppb, 1.38 ppb, and 1.54 ppb, respectively. The sensing mechanism involves Michael type adduct formation due to the nucleophilic addition reaction of cyanide with probes and was confirmed through ¹H NMR titration experiments. In contrast, probe 1d containing an electron withdrawing moiety showed insensitivity towards CN⁻. Therefore, this study provides the efficient strategy to induce AIE character in fluorescent probes and expands the mechanistic approach toward the sensing of toxic CN⁻.

Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes.     

Is home delivery really preferred? a mixed-methods national study in Pakistan

Background

Pakistan has a high maternal mortality ratio and a low rate of skilled birth attendants (SBAs). To address these two important issues, the Pakistan Maternal Newborn and Child Health (MNCH) programme launched the community midwives (CMW) initiative in 2007. CMWs are supposed to conduct deliveries at community level outside health facilities. The purpose of the current study is to document perceptions about CMWs and preferences for birthing place.

Methods

A mixed-methods study was conducted covering four provinces. For the quantitative survey, households were selected through a multistage sampling technique from rural districts. In 1,450 rural households, preferences of respondents about CMW-conducted deliveries were recorded. Qualitative data were obtained through focus group discussions (FGDs) and in-depth interviews (IDIs) with women, community elders, CMWs, and MNCH programme personnel in the same areas where the quantitative study was carried out. In both studies, preferences and the reasons behind particular respondent preferences were recorded. Frequencies of responses were analysed for the quantitative study. Narration and quotes from various types of participants were used to present findings from FGDs and IDIs.

Results

In the quantitative study, 42% of respondents expressed a preference for birthing stations, i.e. a place where CMWs conduct deliveries; 22% preferred home deliveries. Birthing stations were favoured because of the availability of space and equipment and the proximity to women’s homes. These findings were largely supported by the qualitative component, although a range of views about where a CMW should conduct deliveries were expressed.

Conclusion

Insights into where CMWs might provide delivery services were obtained through this study. Birthing stations may be an option as a preferred location for delivery care and should be considered as part of Pakistan’s national CMW programme.

     

Degradation and Mineralization of Azo Dye Reactive Blue 222 by Sequential Photo-Fenton’s Oxidation Followed by Aerobic Biological Treatment Using White Rot Fungi

A two stage sequential Photo-Fenton’s oxidation followed by aerobic biological treatment using two white rot fungi P. ostreatus IBL-02 (PO) and P. chrysosporium IBL-03 (PC) was performed to check decolorization and to enhance mineralization of azo dye Reactive Blue 222 (RB222). In the first stage, selected dye was subjected to Photo-Fenton’s oxidation with decolorization percentage ≈90 % which was further increased to 96.88 % and 95.23 % after aerobic treatment using two white rot fungi P. ostreatus IBL-02 (PO) and P. chrysosporium IBL-03 (PC), respectively. Mineralization efficiency was accessed by measuring the water quality assurance parameters like COD, TOC, TSS and Phenolics estimation. Reduction in COD, TOC, TSS and Phenolics were found to be 95.34 %, 90.11 %, 90.84 % and 92.22 %, respectively in two stage sequential processes. The degradation products were characterized by UV–visible and FTIR spectral techniques and their toxicity was measured. The results provide evidence that both fungal strains were able to oxidize and mineralize the selected azo dye into non-toxic metabolites.