Hemoglobins from bats (Myotis myotis and Rousettus aegyptiacus): a possible example of molecular adaptation to different physiological requirements.

The functional properties of the hemoglobin systems from two different species of bat i.e. Rousettus aegyptiacus and Myotis myotis have been studied as a function of chloride, polyphosphates, pH and temperature. Apart from overall similarities shared with most mammalian hemoglobins, the two systems show significant differences with respect to the effect of chloride and temperature sensitivity. These findings have been related to the different physiological needs of the two species.

Antibiotic NRC-501, a new antibiotic produced by Streptomyces species.

A new antibiotic, NRC-501, was isolated and purified from the fermentation broth of Streptomyces species NRC-501. Physical, chemical, and biological characteristics of the antibiotic NRC-501 were revealed.

Gentamicins.

Gentamicin is a new broad-spectrum antibiotic, basic and water-soluble, produced and developed by Schering Corporation-Bloomfield, New Jersey (1967 and 1968). It is produced by Micromonospora purpurea, a member of a genus of microorganisms from which no other antibiotics have been derived. Paper chromatographic techniques showed the components of gentamicin complex designated as C', C'a, and C2. Gentamicins are bactericidal antibiotics, active in vivo in low concentrations against a wide spectrum of both Gram-positive and Gram-negative organisms. Among the responsive Gram-positive groups of microorganisms are Staphylococcus aureus including many resistant penicillinase producing strains and group A betahemolytic Streptococci. Among the clinically more important species of Gram-positive organisms responsive to gentamicin are both indole-positive and indole-negative Proteus, Pseudomonas, Escherichia coli, Aerobacter, Klebsiella, Salmonella, and Shigella. The production of gentamicins was improved by adding cobalt to the growth medium.