Oxidation of Native and Modified Hemoglobin and Myoglobin by Sodium Nitrate. Effect of Inositol Hexaphosphate

Native and modified hemoglobin, myoglobin and a and phemoglobin subunits were oxidized by sodium nitrite at pH 6. The experiments were carried out under oxy and deoxy conditions with and without inositol hexaphosphate (IHP). It is shown (a) that under oxy condition low concentration of IHP inhibits the oxidation of native hemoglobin only. However, high concentration of IHP inhibits the oxidation of both myoglobin and modified hemoglobin (digested or 0-93-SH groups blocked). This inhibition is partially counteracted by high oxygen pressure, (b) Under deoxy condition the oxidation rates of all hemeproteins studied are significantly faster than that of native hemoglobin. IHP inhibits the oxidation of all except the myoglobin and hemoglobin subunits. It is concluded that although the IHP inhibitory effect on hemoglobin oxidation by nitrite can be explained by the shift of the R↔T conformational equilibrium towards T conformation, some other structural changes such as alteration in molecular surface charges must occur to account for the effect of IHP on the oxidation of hemeproteins devoid of heme-heme interaction

Hemoglobin Subunit-Subunit Affinity-Determinant of Hemoglobin Formation

Hemoglobin A₂ is often elevated in β-thalassemia and decreased in α-thalassemia. This might be due to hemoglobin subunit-subunit affinity variation. It has been inferred from the study of abnormal hemoglobins that the a subunits have higher affinity for β subunits than for δ subunits. However, only in one study has the affinity of α, β, and δ subunits for each other been measured. In this work we have attempted to measure the hemoglobin subunit-subunit affinity with somewhat different approach, i.e., hybridization of hemoglobin A and A₂. It is shown that hybridization and recombination of equal amounts of hemoglobins A and A₂ lead always to the formation of more hemoglobin A than A₂. Incubation of pure α, β, and δ subunits forms more hemoglobin A than A₂ as the availability of a subunits declines. It is concluded that hemoglobin a subunits have approximately four-fold higher affinity for β subunits than for the δ subunits under these experimental conditions. This subunit-subunit affinity difference, which has been attributed to the variation in molecular electrostatic charges, explains the variation of hemoglobin A₂ levels in thalassemia syndromes

A linear algorithm for the grundy number of a tree

A coloring of a graph G = (V,E) is a partition {V1, V2, . . ., Vk} of V into independent sets or color classes. A vertex v Vi is a Grundy vertex if it is adjacent to at least one vertex in each color class Vj . A coloring is a Grundy coloring if every color class contains at least one Grundy vertex, and the Grundy number of a graph is the maximum number of colors in a Grundy coloring. We derive a natural upper bound on this parameter and show that graphs with sufficiently large girth achieve equality in the bound. In particular, this gives a linear time algorithm to determine the Grundy number of a tree

The Mechanism of Empathy in Forum Theater

Even though the concept of “Empathy” was mentioned in the earliest texts about performance, there has always been a dispute among theatre theorists in different eras regarding its impact on the audience. Although some have considered empathy as the basis of the theatre, others viewed it as a dangerous ground that can result in inappropriate and unhealthy feelings in the audience. Recent findings of neuroscientists have revealed that empathy (with both real people and fictional characters) is inevitable for human beings, and its unconscious mechanism exists in every mentally healthy person. I believe that this inherent ability can allow us to contribute to making practical changes in the attitudes and behaviors of theatre audiences by utilizing their empathy. As pointed out in this essay, Forum Theatre, as a technique of the Theatre of the Oppressed, is more based than anything on the empathy of its spectators (or so-called Spect-actors by Boal). More than any other theatrical form, it provides a chance for its audiences to identify with theatre subjects, which in turn, through repetition and practice, contributes to the emergence of neural patterns, thereby improving the audience`s reactions in similar situations in everyday life