Coordination of arm movement during locomotion in ophiurans

During movement of the ophiuranAmphipholis kochii Lutken, any one of its arms can point forward and, consequently, any arm can perform different functions. The arm, when separated from the ophiuran together with the adjacent part of the nerve ring, is capable of complex motor acts, including locomotion. Division of the nerve ring in the ophiuran disturbs coordination of the arms. The results of experiments in which one or more arms were amputated showed that the choice of leading arm and of method of locomotion depends mainly on afferent impulses received from the arms. The results indicate that the neural centers of individual arms possess relative autonomy. Coordinated working of the centers is achieved through their interaction. This interaction ensures the distribution of functions between the arms in accordance with the motor task to be undertaken and coordinates the activity of the arms in time. The dominant role in the distribution of functions between the arms is played by the center of the leading arm, which controls the activity of at least the adjacent centers.Institute of Oceanology, Academy of Sciences of the USSR, Moscow. Institute of Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. Moscow State University. Translated from Neriofiziologiya, Vol. 8, No. 5, pp. 529–537, September–October, 1976.     

Fluorosis in black-tailed deer.

Marked dental disfigurement and abnormal tooth wear patterns were observed in black-tailed deer (Odocoileus hemionus columbianus) taken from an area near an industrial fluoride source in northwestern Washington. Fluoride levels in the bones of these deer were from 10 to 35 times higher than levels in the bones of normal animals. These levels are similar to those associated with fluorosis of cattle.     

Effects of prostaglandins and other drugs on the cyclic AMP content of cultured bone cells.

Prostaglandins of the E-series (PGE1 and PGE2) may be involved in disease-related, localized loss of bone. E-prostaglandins increase the cyclic AMP content of many cells; and, to determine if their effects on bone are mediated by cyclic AMP, we examined the effects of E-prostaglandins and of other agents on the cyclic AMP content of cultured bone cells. PGE2 produced a rapid, marked and dose-related increase in the cyclic AMP content of confluent monolayers of bone cells isolated from newborn rat calvaria. At 2.8 X 10(-6) M, PGE1 and PGE2 had approximately the same effect, while the effect of PGF2alpha was much less pronounced. In the presence of theophylline, PGE2 had a more marked effect than parathyroid hormone (PTH) and the combination of PGE2 and PTH had a synergistic effect. The divalent, cationic, ionophore, A23187, produced an increase in cellular cyclic AMP and had an additive effect in combination with PGE2. Synthetic salmon calcitonin (CT), which inhibits the bone resorptive effect of PGE2, increased cellular cyclic AMP and had an additive effect in combination with PGE2. A prostaglandin antagonist, SC-19220, partially inhibited the resorptive effect of PGE2 and reduced its effect on cellular cyclic AMP. The calcium antagonist, D600, inhibited the bone resorptive effects of PGE2 but had no effect on increased cellular cyclic AMP produced by PGE2. The marked effect of PGE2 on bone cell cyclic AMP suggests that this action is involved in the mechanism of PGE2-related bone loss. The fact that agents with different effects on PGE2-induced increases in cellular cyclic AMP can inhibit its resorptive actions, suggests that PGE2-induced changes in cyclic AMP may be related less to its resorptive actions than to its inhibitory effect on bone formation.     

Studies on hemoglobin variants in Korean cattle

814 hemoglobin samples from Korean cattle were investigated by starch gel electrophoresis for the detection of hemoglobin variants. A new variant of cattle hemoglobin, called Hb, H, was recognized. It has a slower rate of migration than Hb A.
Hemoglobin types from 814 Korean cattle were as follows: 652 of Hb AA type (80.1 %), 133 of Hb AB (16.4 %), 12 of Hb AC (1.5 %), 9 of Hb BB (1.1 %), 2 of Hb BC (0.2 %), 4 of Hb AH (0.5 %), 1 of Hb CH (0.1 %), 1 of Hb HH (0.1 %). These figures correspond to the frequencies: Hb^A = 0.893, Hb^B = 0.093, Hb^c =0.009, Hb^H = 0.004.
Gene frequencies at the Hb locus in Korean cattle were compared among six population from different provinces. Generally, high frequencies of Hb^A were observed in each province.     

Effect of carbon source on conidiogenesis in fonsecaea dermatitidis,agent of chromomycosis

Hormiscium dermatitidis Kano is a well known etiological agent of cutaneous and generalized chromomycosis. However, the generic designation of this fungus has long been a much debated question. The results of the present study of the type culture ATCC 28869 indicate that the fungus is polymorphic, producing a Phialophora state in media containing glucose or maltose and a Cladosporium state in media containing galactose or melibiose. Morphologically and developmentally this chromomycotic agent is closely related to Fonsecaea pedrosoi (Brumpt) Negroni and should be classified as Fonsecaea dermatitidis (Kano) Carrión.     

Primary sequence of the beta-chain of Badger haemoglobin.

Badger (Meles meles) haemoglobin was purified by paper electrophoresis and converted into globin. Chain separation was carried out on a CM-cellulose column in the presence of 8 M urea. The beta-chain was aminoethylated, purified by gel filtration and submitted to tryptic digestion. A fingerprint obtained with the enzymic digests showed 17 distinct ninhydrin-positive spots from which 20 pure peptides were isolated by further electrochromatographic separations. These peptides were sequenced using Dansyl-Edman and Ptc-Edman degradation techniques. The presence of amide residues was confirmed after aminopeptidase M hydrolysis. Taking human haemoglobin beta-chain as a model, the covalent structure could be completely resolved without the help of any further overlapping technique. The following substitutions were noted (badger/human, position): Ala/Pro5, Ser/Ala13, Tyr/Phe41, Asp/Glu43, Ser/Ala70, Glu/Asp73, Lys/Ala76, Asn/His77, Lys/Thr87, Lys/Arg104 and Gln/Pro125. A comparison with other haemoglobin beta-chains already sequenced shows a greater similarity with dog haemoglobin, the only example of beta-chain of known structure in the order of Carnivores.     

Generation of electric current by chromatophores of Rhodospirillum rubrum and reconstitution of electrogenic function in subchromatophore pigment-protein complexes

Lipoprotein complexes, containing (1) bacteriochlorophyll reaction centers, (2) bacteriochlorophyll light-harvesting antenna or (3) both reaction centers and antenna, have been isolated from chromatophores of non-sulphur purple bacteria Rhodospirillum rubrum by detergent treatments. The method of reconstituting the proteoliposomes containing these complexes is described. Being associated with planar azolectin membrane, proteoliposomes as well as intact chromatophores were found to generate a light-dependent transmembrane electric potential difference measured by Ag/AgCl electrodes and voltmeter. The direction of the electric field in proteoliposomes can be regulated by the addition of antenna complexes to the reconstitution mixture. The reaction center complex proteoliposomes generate an electric field of a direction opposite to that in chromatophores, whereas proteoliposomes containing reaction center complexes and a sufficient amount of antenna complexes produce a potential difference as in chromatophores. ATP and inorganic pyrophosphate, besides light, were shown to be usable as energy sources for electric generation in chromatophores associated with planar membrane.     

Heterogeneity in the conformation of different protein fractions from the human erythrocyte membrane

We have isolated 5 families of proteins from human red blood cell membranes and characterized their secondary structure by ultraviolet circular dichroism measurements. The protein families were prepared by selective solubilization from ghosts under nondenaturing conditions. We find that the intact ghost has a mean α-helix fraction of 0.37, whereas a low-ionic-strength extract (bands 1, 2, 5, “spectrin”) has a substantially higher helix fraction, 0.55. Further extraction of the ghosts with para-chloromercuribenzoate yields bands 2.1, 4.1, 4.2, and 6; their helix content is only 0.17. Finally, the major intrinsic protein, band 3, was solubilized by a nonionic detergent. Its helix fraction is 0.38.     

Regulation of aquatic diptera by planaria

The planarian,Dugesia dorotocephala (Woodworth) demonstrated a capacity to regulate two experimental host groups,Culex mosquitoes and chironomid midges, at low densities in south California. Inoculations in 1974 of 5 mature planaria/m² of water surface in flood control settling basins produced 82.4%, 60.6% and 63.7% chironomid control in August, September and October, respectively. Laboratory tests produced 86.7% larval kill in 24 hrs and 100% in 48 hrs. In rice paddy habitatsCulex tarsalis Coquillett andC. peus Speiser were reduced by 79.3%, 75.0% and 77.3% in August, September and October, respectively, by planaria inoculations of 25/m² of water surface. A tendency to prefer later instars was indicated.Dugesia were observed to persist in all treated replicates through the study period; and although exact densities could not be estimated, at least a quadrupling of their population appeared to have occurred in 4 months following inoculations in June and July. Planaria offer practical and possibly superior alternatives to chemical pesticides in the control of some aquatic Diptera.     

Intramolecular distortion of the α-helical structure of polypeptides

Broadening of the infrared amide A, amide I and amide II bands of α-helical polypeptides has been observed for thermodynamically unstable α-helices. This spectroscopic fact can be explained now by the geometrical distortions of the backbone of the helical structure. Two models for distorted helices which include regular or irregular distortions of the angles of internal rotation of the main polypeptide chain have been considered. It is pointed out that the instability of α-helix is associated with irregular distortions of the polypeptide backbone.