Interactions of Thymine and Uracil with Copper, Cobalt and Silver Ferrocyanides and the Implications in Chemical Evolution

Effects on pH based adsorption of nucleic acid bases (thymine and uracil) at two different concentrations 1 x 10-4 M and 1 x 10-5 M on copper, cobalt and silver ferrocyanides were studied over a pH range (1.0 – 10.0) at temperature 30±1ºC. The progress of adsorption was followed spectrophotometrically by measuring the UV absorbance of the nucleic acid base solutions at their corresponding max. Maximum adsorptions were found at neutral pH for both thymine and uracil. Effects of concentrations on adsorption of thymine and uracil on copper, cobalt and silver ferrocyanides were studied in a concentration range 10-4 – 10-5 M at neutral pH 7.0 ± 0.1 and at temperature 30±1°C. The interaction followed the Langmuir type of adsorption in general in the concentration range of 10-4 to 10-5 M of thymine and uracil solution. The uptake of nucleic bases on metal ferrocyanides followed the order of CuFc > AgFc > CoFc for the adsorption of thymine and CuFc > CoFc > AgFc for the adsorption of uracil. Effects of the presence of salts on the adsorption of thymine and uracil on metal ferrocyanides also had been studied. The insoluble metal ferrocyanides’ interaction with biomolecules must have either formed metal complexes or could have enhanced the formation of biopolymers in fluctuating environment.

pH-Control in Aptamer-Based Diagnostics, Therapeutics, and Analytical Applications

Aptamer binding has been used effectively for diagnostics, in-vivo targeting of therapeutics, and the construction and control of nanomachines. Nanostructures that respond to pH by releasing or changing affinity to a target have also been used for in vivo delivery, and in the construction of sensors and re-usable nanomachines. There are many applications that use aptamers together with pH-responsive materials, notably the targeted delivery of chemotherapeutics. However, the number of reported applications that directly use pH to control aptamer binding is small. In this review, we first discuss the use of aptamers with pH-responsive nanostructures for chemotherapeutic and other applications. We then discuss applications that use pH to denature or otherwise disrupt the binding of aptamers. Finally, we discuss motifs using non-canonical nucleic acid base pairing that can shift conformation in response to pH, followed by an overview of engineered pH-controlled aptamers designed using those motifs.

DETECTION OF SPECIFIC CAUSES OF TUBERCULOSIS IN THE DAIRY CATTLE OF BANGLADESH AGRICULTURAL UNIVERSITY BY SEQUENCING AND SEQUENCE ANALYSIS

Tuberculosis (TB) is a chronic disease of man and animal. In this study intradermal tuberculin test, necropsy, histopathology, polymerase chain reaction (PCR) and sequencing techniques were used to diagnose specific cause of TB in dairy cattle of Bangladesh Agricultural University, Mymensingh. Intradermal tuberculin tests were carried out on randomly selected 100 dairy cattle. Tuberculin test positive cattle (N=05) were examined at necropsy and granulomas in lungs was seen in three cattle. Caseous necrosis and swelling of lymphnodes was seen in prescapular (N=01) and mesenteric (N=02) lymphnodes. In a case nodular lesion was seen in lungs and mesenteric lymphnodes. Portion of infected lungs and lymphnodes were snap frozen, extracted genomic DNA and PCR protocols was adapted targeting MPB83 gene. Result of PCR showed amplification of 600bp fragments in five cases. The MPB83 gene although specific for M. Bovis, the gene is less abundantly expressed by M. tuberculosis. To differentiate infectivity due to M. Bovis and M. Tuberculosis, two more PCR were adapted targeting pncA and oxyR genes. Out of five cattle tested in PCR all samples generated pncA specific 185bp and oxyR gene specific 270bp amplicons. The sequencing of MPB83, pncA and oxyR genes were carried out. Results of sequencing did not show mutation in MPB83 gene. Sequencing of pncA gene showed replacement of nucleic acid base (guanine to cytosin) in position 169 in cattle no. 5. Similarly, sequence analysis of oxyR gene (n=05) showed replacement of nucleic acid base (adenine to guanine) in position 285 in cattle no. 5. The cattle no. 5 was confirmedly infected with M. Tuberculosis and rest of the cattle were infected with M. Bovis. The tuberculin tests, necropsy, histopathology and PCR amplification of MPB83 gene may not contribute species specific detection of Mycobacterial infectivity in cattle. Sequencing and sequence analysis of pncA and oxyR genes found to differentiate infectivity in cattle due to M. Bovis and M. Tuberculosis. Both of the bacterial species are extremely zoonotic and dairy cattle of Bangladesh Agricultural University were infected with both M. Bovis and M. Tuberculosis. It needs to tests all the dairy cattle twice in a year with tuberculin tests and dispose test reactors in order to minimize zoonotic risk.

An optimized charge penetration model for use with the AMOEBA force field

Inclusion of charge penetration corrects the short-range error in the electrostatic model of the AMOEBA force field, and improves the accuracy of interactions ranging from nucleic acid base stacking to protein–ligand binding.

Self-assembly of hydrogen-bonded supramolecular complexes of nucleic-acid-base and fatty-acid at the liquid–solid interface

The interesting sandwich-like architectures were formed at the liquid–solid interface by using a binary system consisting of guanine and stearic acid.