Changes in protein synthesis in rats in response to endurance training

Experiments were conducted to investigate the influence of endurance exercise training on protein synthesis in skeletal muscle, heart, and liver. Training decreased incorporation of [¹⁴C]-leucine into proteins of the stromal fraction of muscle but there was no change in amino acid incorporation into proteins of the sarcoplasmic and myofibrillar fractions. Incorporation of [¹⁴C]-leucine into the protein of heart, liver, and plasma was depressed in trained rats compared to untrained rats. The specific radioactivity of [¹⁴C]-leucine was similar in tissues of trained and untrained rats and thus the depressed amino acid incorporation represents a decrease in the rate of protein synthesis. These observations demonstrate that the adaptation of muscle protein metabolism to endurance training is quite different than the alterations during work-induced hypertrophy of muscle. The difference in adaptation probably relates to the functional differences between the types of exercise. However depression of protein synthesis in trained rats is a general effect in several tissues and not an effect localized in muscle tissue.     

The Cladocera of Sri Lanka (Ceylon), with remarks on some species

The freshwater Cladocera of Sri Lanka has been revised based on the study of over 700 zooplankton samples collected from all habitat types during 1965–1980. The cladoceran fauna is represented by six families; members of the families Polyphemidae, Leptodoridae and Holopedidae are absent. The common temperate genus Daphnia is rare.Sixty-two species have been recorded from Sri Lanka. Of these, five are new records. Remarks on a few species are given with illustrations. The distribution of Cladocera in different types of habitats is discussed. The greatest species diversity was found in ponds. The Sri Lankan fauna is numerically and in species diversity typical of tropical cladoceran fauna. It resembles the southern Indian fauna very closely except for the absence in Sri Lanka of the genera Acroperus and Camptocercus.     

Spore survival during batch dry rendering of abattoir waste.

Normal batch dry rendering practice does not ensure sterile products, because bacterial spores are protected against thermal denaturation by the high fat-low water content environment which results from drying the materials at temperatures below those required for sterilization.     

On the conformational dependence of the proton chemical shifts in nucleosides and nucleotides III. Proton chemical shifts of 5′-nucleotides as a function of different conformational parameters

The variation of the chemical shift of the protons of 5′-UMP and 5′-AMP is calculated as a function of χ_CN, ψ and ? torsion angles. The shift of H8 of 5′-AMP and H6 of 5′-UMP is found to be very sensitive to the value of χ_CN. For the anti conformations the shift of these protons is more sensitive to the value of the rotation about CS′-05′ than about C4′-CS′. For the protons of the ribose the calculations show that for the C2′-endo pucker H3′ and H2′ undergo the largest chemical shift variations when ? and ψ vary. The calculated variations are considered in relation with the role of the conformation of the nucleotides in the chemical shift variation between mono and polynucleotides and between the different helical structures of polynucleotides.     

DIASTOLIC OPENING OF THE AORTIC VALVE (AV) IN A CASE OF AORTIC INSUFFICIENCY DUE TO AV FENESTRATION

A patient with severe aortic insufficiency due to fenestration of the non-coronary aortic valve leaflet is described. A preoperative echocardiogram demonstrated early closure of the mitral valve and early diastolic separation of the aortic valve leaflets. These findings disappeared after partial surgical correction and subsequent hemodynamic improvement. Premature opening of the aortic valve is common in severe aortic insufficiency.     

Distribution of ABO blood groups and other genetic markers in mothers of infants with congenital malformations

The distribution of ABO and Rh (antigen D) blood groups and of serum albumin, haptoglobin and transferrin variants, in a group of mothers of malformed newborns was investigated. In the first phase of the study, the results showed borderline statistical differences in the distribution of the transferrin types between the study group and a suitable control population. The second phase of the research, where only transferrin phenotypes were studied, showed the same trend as in the first one, but the results were not statistically significant. We conclude that probably there are no true distribution differences, but that it would be desirable to study this problem in a different ethnic group.     

Aggregation of mono- and dinucleosomes into chromatin-like fibers

Three classes of chicken erythrocyte chromatin particles differing in their content of lysine-rich histones and/or spacer DNA have been studied in order to determine their ability to aggregate into complexes resembling those observed in native chromatin. The complexes have been obtained in the presence of MgCl₂ and NaCl and studied by electron microscopy. Mononucleosomes, containing spacer DNA and histones H1 and H5, give rise to thick (about 70 nm) ellipsoidal particles in the presence of 0.5 mM MgCl₂. These particles are disrupted by the addition of small amounts of NaCl (5–20 mM). On the other hand in 0.5 mM MgCl₂ dinucleosomes give rise to regular fibrous complexes of about 40 nm in diameter which are very similar to native chromatin fibers. These complexes are much more stable when NaCl is added. We conclude that for the stability of nucleosomal aggregates, similar to native chromatin fibers, a continuity of DNA structure is not required, but the presence of divalent cations, spacer DNA and lysine-rich histones is essential.     

Enhancement of Endogenous Release of Glutamate and γ-Aminobutyric Acid from Hippocampus CA1 Slices After In Vivo Long-Term Potentiation

The effect of long-term potentiation (LTP) on endogenous amino acid release from rat hippocampus slices was studied. LTP was induced in vivo by application of a tetanus (200 Hz, 200 ms) to the Schaffer collateral fibers in unanesthetized rats. Endogenous release of glutamate and gamma-aminobutyric acid (GABA) was investigated 60 min after tetanization in CA1 subslices of potentiated and control rats. No significant effects of LTP were observed in basal and K(+)-induced Ca(2+)-independent release components of these amino acids. In contrast, K(+)-induced Ca(2+)-dependent release of both glutamate and GABA increased approximately 100% in slices from potentiated rats. No differences were observed in total content of glutamate and GABA between the subslices from control and LTP animals. These results suggest a persistent increase in the recruitment of the presynaptic vesicular pool of glutamate and GABA during LTP.     

Thidiazuron stimulates shoot organogenesis and somatic embryogenesis in white ash (Fraxinus americana L.)

Immature and mature nonstratified seeds of white ash (Fraxinus americana L.) were dissected transversely and 2/3 of each seed was placed onto agar-solidified Murashige and Skoog medium. Adventitious buds, shoots, and somatic embryos formed on callus, cotyledons, and hypocotyls of the resulting seedlings. Shoot organogenesis was induced on explants cultured on medium with 10 M thidiazuron but not on explants on media with benzyladenine (BA) or isopentenyladenine. Not all seed sources were equally capable of shoot organogenesis and embryogenesis. Atypical of adventitious regeneration of other woody plants, mature seed explants of white ash were more organogenic with shoots that elongated better than explants from immature seeds. Somatic embryogenesis was observed in cultures where mature seeds were first cultured for 4 weeks on a medium containing 10 M adenine 2,4-dichlorophenoxyacetic acid in combination with 0.1 and 1.0 M thidiazuron, followed by transfer to a medium containing 0.05 M 6-benzyladenine and 0.5 M naphthaleneacetic acid. Adventitious shoots and epicotyls from both seedlings and germinated somatic embryos were rooted under intermittent mist and acclimatized to the greenhouse.Abbreviations BA 6-benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - IBA indolebutyric acid - 2iP isopentenyladenine - NAA naphthaleneacetic acid - TDZ thidiazuron-N-phenyl-N-1,2,3-thiadiazol-5-ylurea - WPM woody plant medium