Photodynamic inactivation of isolated crayfish mechanoreceptor neuron: different death modes under different photosensitizer concentrations

To study the mechanism of photodynamic nerve cell killing, isolated crayfish mechanoreceptor neurons were photosensitized by the sulfonated aluminum ophthalocyanine Photosens. Neuron activity was continuously recorded until irreversible abolition. Intense (10(-5) M Photosens) or weak (10(-7) M Photosens) photosensitization induced different bioelectric neuron responses: firing activation followed by irreversible depolarization block or gradual inhibition until firing abolition, respectively. These bioelectric responses were accompanied by different biochemical and morphological changes. In the case of intense photosensitization, neuron nuclei swelled and then shrank. Succinate dehydrogenase (SDH) was inhibited, and the plasma membrane was compromised just after firing cessation. Weak photosensitization did not induce these changes but caused swelling of the endoplasmic reticulum and destruction of the matrix, cristae and membranes in some of the mitochondria. Other mitochondria, however, retained the normal structure. Plasma membrane damage, SDH inhibition, nucleus shrinkage and impairment of the nuclear border occurred after 2-4 h. It is concluded that intense photosensitization induced necrotic processes during irradiation, whereas weaker impact caused delayed necrosis 2-4 h later. The observed electrophysiological neuron responses to photodynamic therapy may be considered as early hallmarks of different modes of forthcoming cell death.     

Olivomycin and related antibiotics

Conclusions On the basis of its chemical properties and spectral characteristics, structure I has been established for the aglycone of the olivomycin antibiotics, olivin.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 304–316, 1969For part XIII, see [1], and for a preliminary communication, see [2]. The subject matter of the present paper was presented in part at the International Congress on Antibiotics (Prague, 1964), and at the IX-th Mendeleev Conference on General and Applied Chemistry (Kiev, 1965).     

Olivomycin and related antibiotics XXVIII. Monomeric composition of aureolic acid and proof that the antibiotics LA-7017 and mithramycin are identical to it

Summary 1. It has been shown that aureolic acid, antibiotic LA-7017, and mithramycin are identical.2. It has been established that aureolic acid is a glycoside of chromomycinone (I) and contains the monosaccharides D-olivose (II), D-oliose (III), and D-mycarose (IV) in a ratio of 3 : 1 : 1.For Communication XXVII, see [1], and for a preliminary communication see [2].M. M. Shemyakin Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. All-Union Scientific-Research Institute of Antibiotics. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 537–541, July–August, 1972.     

Olivomycin and related antibiotics

Summary 1. From the culture fluid of the ray fungusActinomyces olivoreticuli four individual antibiotics, olivomycins A, B, C, and D have been isolated.2. The acid degradation of olivomycins A, B, C, and D has been carried out with the formation of the aglycone olivin and the carbohydrates olivomycose, olivomose, olivose, oliose, and (or) their derivatives.3. The qualitative and quantitative monomeric composition of olivomycins A, B, C, and D has been elucidated and their empirical formulas have been established.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 5, pp. 331–339, 1967For previous communications, see [1]; for Communication IX, see [2].     

Olivomycin and related antibiotics

Conclusions It has been shown that the five monosaccharide residues forming the carbohydrate moiety of the antibiotic olivomycin A form two unbranched chains attached to the hydroxyls in positions 2 and 6 of the aglycone and terminated by isobutyrylolivomycose and olivomose.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 561–566, 1969For a preliminary communication, see [1], and for part XVI, see [2].     

Intensification of the Nitrate Anion Reduction on a Membrane Palladium Electrode

Polarization curves of electroreduction of nitrate anions in sulfuric acid aqueous solutions on a Pd/Pd palladium electrode with the opposite side kept at different constant potentials in the region of Pd–H -phase formation are compared. The reduction rate of nitrate anions is shown to be substantially higher on a membrane electrode, provided the conditions of hydrogen supply from the membrane's opposite side to the reaction zone are realized. This phenomenon is caused by the reduction of a chemisorbed intermediate (a certain N(III) form) by hydrogen diffused through the membrane. It is shown that the measurements of hydrogen diffusion currents through a membrane can be used in plotting hydrogen sorption isotherms in the Pd–H -phase.     

Flavonoid components of propolis

Conclusions The following flavonoids have been isolated from propolis and identified: acacetin (I), 7,4-dimethoxyflavone (II), kaempferide (III), rhamnocitrin (IV), 5,7-dihydroxy-3,4-dihydroxyflavone (V), 3,5-dihydroxy-7,4-dimethoxyflavone (VI), (–)-pinostrobin (VII), and (–)-5-hydroxy-7,4-dimethoxyflavanone (VIII).Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 476–482, 1969