Madhu Tiwari

One pot synthesis of coordination polymer 2,5-dimercapto-1,3,4-thiadiazole–gold and its application in voltammetric sensing of resorcinol

Herein, we report a one pot synthesis of a coordination polymer using 2,5-dimercapto-1,3,4-thiadiazole (DMTD) with gold (Au) and the characterization of the polymer by FTIR, Raman spectroscopy, UV-visible spectroscopy, XPS, XRD, 13CNMR, HRTEM, gel permeation chromatography and TGA. Results show that Au ions get coordinated by the diazole and sulfydryl groups of DMTD throughout the polymeric chain. The polymeric layers are stabilized through π–π stacking and hydrophobic interaction. XRD data reveals the crystalline nature of DMTD–Au coordination polymer. The kinetic parameters, such as the energy of activation and the regression value of the DMTD–Au decomposition, have been determined by exploiting thermogravimetric data. HRTEM analysis establishes the nanostructure of the polymeric material DMTD–Au. Its voltammetric study reveals that the synthesized coordination polymer DMTD–Au exhibits excellent electroactivity towards resorcinol and facilitates fast electron transfer kinetics, which is employed for electro-sensing applications. To the best of our knowledge we are the first to report this coordination polymer DMTD–Au modified carbon paste electrode (DMTD–Au/CPE) for the electrochemical detection of resorcinol (RS). The DMTD–Au modified carbon paste electrode has been found to be highly sensitive towards resorcinol due to its strong interaction through intermolecular hydrogen bonding. Under the optimized conditions, the modified electrode exhibit resorcinol oxidation at low over potential (0.55 V) and the anodic peak current shows a linear response with sensitivity and limit of detection of 0.019 μA nM−1 and 29.77 nM, respectively, at a S/N (signal-to-noise ratio) of 3.

The nanocrystalline coordination polymer of AMT-Ag for an effective detection of ciprofloxacin hydrochloride in pharmaceutical formulation and biological fluid.

The present report highlights a cost effective and portable AMT-Ag nanocrystalline coordination polymer (NCCP) based electrochemical sensor for an efficient sensing of biologically active drug molecule ciprofloxacin hydrochloride (CFX). The AMT-Ag NCCP, is synthesized using an easily accessible organic ligand 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) with silver nitrate. In the infinite polymer array of AMT-Ag, silver (I) centers are bridged by tecton AMT through the exocyclic thiol and amino linkage. A successful ultra‒trace detection of CFX has been achieved due to the prominent electron channeling through the pores of polymeric nano-crystallites. The efficient charge transfer arises at the interface of electrolyte and AMT-Ag nano-crystals anchored electrode through hydrophobic interaction and π-π electron coupling. The voltammogram reveals the critical redox features of CFX and provides a clear representation about the steps involved in the AMT-Ag assisted oxidation of CFX. This specific signature further applied in the voltammetric assay of CFX in pharmaceutical formulation (eye drops) and biological fluid (urine) by a significantly high sensitivity (0.002µA/µM and 0.007µA/µM) and detection limit (22nM and 60nM) respectively without any interference. Therefore, the developed AMT-Ag NCCP could serve as a highly valuable platform for the fabrication of high-performance electrochemical sensors for the detection of biologically important drug molecules.

Absence of NsiI Polymorphism in Growth Hormone Receptor (GHR) Gene in Indian Cattle Breeds

The objective of the present study was to investigate the polymorphism in 5′ non-coding region of growth hormone receptor (GHR) gene in Sahiwal (n = 53) and Hariana (n = 50) cattle using NsiI/PCR-RFLP assay. Amplification of DNA sample revealed 302bp product using specific primer pairs and digested by using NsiI restriction enzyme. All the screened animals were found monomorphic in nature for GHR/NsiI polymorphism. It revealed that only one type of uncut banding pattern (AA genotype); which was of 302bp. We could not identify any animal with GG and AG genotypes. Consequently, we could not perform association studies with milk production traits.

Characterization of 5’ Upstream Region and Identification of Polymorphism in Intron 1 of Prolactin (PRL) Gene using HaeIII PCR-RFLP in Indian Cattle Breeds

Prolactin (PRL) gene is an important lactogenic candidate gene, plays a crucial role in mammary gland development and in the initiation, maintenance of lactation and expression of milk protein genes. In the present study, characterization of PRL 5′ upstream region and investigation of status of intron 1 polymorphism was carried out in Indian cattle breeds. An 857 bp fragment of 5′ upstream region of PRL gene consisting of part of promoter, exon1 and partial intron 1 was amplified by PCR and subsequently sequenced in Indian breed of cattle. Nucleotide sequences of PRL 5′ upstream region exhibited a high degree (>98%) identity among Indian as well as exotic cattle breeds. HaeIII polymorphism screening in PRL intron 1 of Indian cattle breeds including Sahiwal (n = 154) and Hariana (n = 50) revealed monomorphic pattern, only, AA genotype (deletion homozygote) was found and confirmed by sequencing. The obtained sequences of PRL after aligning was revealed absence of HaeIII recognition site GGCC due to deletion of G and consequently, we could not perform the association study of this deletion with milk production traits.

Association Between Polymorphisms of Solute Crrier 27 A1 Gene with Milk Production Traits in Indian Sahiwal and Hariana Cattle

This study investigated the status of Solute carrier 27A1 (SLC27A1) polymorphism in Indian cattle breeds (n = 102) using PCR-RFLP assay and its association with milk production and reproduction traits. Two region of SLC27A1 gene consisting of exon 3 and exon 4 revealed 261 and 160 bp products, respectively. The digestion of 261 bp product using SacII restriction enzyme (RE) resulted in monomorphic pattern; only GG genotype. The BsaHI/PCR-RFLP assay revealed three types of genotypes, namely, TT (160 bp), CC (106 and 54 bp) and heterozygous CT (160, 106 and 54 bp) genotypes with frequencies 18.62, 59.80 and 21.56 %, respectively. The allelic frequency of C and T alleles were 0.71 and 0.29, respectively. Association study revealed that lactation period (LP), milk yield in 300 days (MY300), calving interval (CI), peak yield (PY) and days to reach peak yield (DRPY) had non-significant difference among all the three genotypes in first and second lactations. while, significant difference was (P=0.028) observed for total milk yield (TMY), where TMY of CC genotype was significantly higher than CT and TT genotypes in only first lactation. Results indicated that C allele for SLC27A1 gene can be used as candidate gene for marker assisted selection in Sahiwal and Hariana cattle.