DNA as an enzyme: The effect of imidazole derivatives as cofactors and metal ions as activators or inhibitors

Objective: a highly sensitive spectrofluorometric method using dichlorofluorescin (LDCF) was employed to study the rate of electron transfer reaction in presence of DNA and some imidazole derivatives. Results: in our experiments, DNA possessed a unique enzyme like catalytic function in oxidative conversion of nonfluorescent LDCF to fluorescent dichlorofluorescein (DCF). The rate enhancement was associated with the turn over constant: kp � 10 s1 for DNA and cinnamoyl imidazole as a cofactor. A biphasic saturation curve was observed when the reaction velocities were measured at fixed concentrations of DNA and variable amounts of carnosine. Each of the biphasic trends gave the Scatchard values of Vm1/Km1 � 3.1 105 and Vm2/Km2 � 5.1 106 with Km1 � 2.7 105 M and Km2 � 4.2 104 M for carnosine. Although Ni (II) and Pb (II) induced inhibition in the rate of electron transfer reaction in presence of DNA and cinnamoyl imidazole or carnosine, metal ions such as Mg (II), Cd (II), Zn (II) and Fe (II) caused activation of DNA. The rates of the reactions showed strong dependency on electronegativity and conductivity of metal ions, namely the increase in activity of DNA in presence of each metal ion correlated inversely with the electronegativities of the metal and was also related directly to the conductivities of individual metal. These effects were observed both in activation and also inhibition of DNA reaction. Imidazole compounds, e.g., Histidine, N-trans cinnamoyl imidazole and imidazole along with Cd (II) produced further rate enhancement. The increase was several times greater with N-trans cinnamoyl imidazole. Conclusions: this effect could provide additional evidence for the importance of an intermediary cofactor that could facilitate the transfer of the electron from the reaction site to the DNA conductive chord. This was most guaranteed by the conjugated system provided by a compound such as N-trans cinnamoyl imidazole. © 2003 The Canadian Society of Clinical Chemists. All rights reserved. Keywor

Raman

Intracellularly grown gold nanoparticles as potential surface-enhance

Quantitative Analysis of Inter-object Spatial Relationships in Biological Images

Study of spatial relations between biological objects is crucial for understanding biological processes. Monitoring drug or particle delivery inside cells and studying the dynamics of subcellular proteins are some of the examples. Biological applications have varying demands in terms of speed and accuracy. While accuracy may be the most important factor for small-scale biology, speed is also a concern for high-content/high-throughput screening applications. In this paper we present a variety of algorithms for inter-object spatial relations in two-and three-dimensional space. These algorithms provide trade-off between speed and accuracy, depending on the requirements of the application. Results for speed and accuracy are reported for real as well as synthetic data sets

Effect of date palm (Phoenix dactylifera)seed extract as a dietary supplementation on growth performance immunological haematological biochemical parameters of common carp

This study aimed to assess the effect of date palm (Phoenix dactylifera) seed (DPS) extract at 0.5%, 1%, 2% and 4% as a dietary supplement over 60 days, on the growth and immune-physiology of common carp (Cyprinus carpio) fingerlings. The weight gain in fish fed with 0.5% DPS was significantly greater than other treatments and fish fed a control diet with no DPS (p < 0.05). With increasing DPS dosage above 0.5%, weight gain and growth rate gradually declined. Feed conversion ratio in fish fed 0.5% DPS was lower than other treatments, but not significantly so, except for the highest DPS concentration (4%). With respect to immunophysiological variables, fish treated with 0.5% DPS leucocyte, neutrophil, lymphocyte and monocyte counts that were generally equivalent to fish on a control diet, but significantly lower than fish treated with greater concentrations of DPS (p < 0.05). Chemilumincene response and lysozyme activity, as well as levels of total protein and albumin, were higher in all treated groups than the control. The highest levels of iron and high density lipoprotein (HDL) were observed in fish fed with 0.5% DPS, while the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), glucose, cholesterol, triglyceride, low density lipoprotein (LDH), thyrotropin, thyroxine and triiodothyronine were lower level in fish fed with 0.5% DPS than in all other treatments. In aquaculture practice, use of 0.5% DPS in commercial carp feed can improve the growth rate and condition of fish