Low molecular weight viral RNAs transcribed by RNA polymerase III during adenovirus 2 infection

Nuclei isolated from human cells productively infected with adenovirus 2 have been shown to synthesize four low molecular weight RNA species which hybridize efficiently to viral DNA. One species corresponds to the 5.5S or VA RNA (Ohe, Weissman, and Cooke, 1969), and is designated V156. The other three species are novel and have been designated V200, V140, V130, since they are approximately 200, 140, and 130 nucleotides in length, respectively. These viral RNAs retain their distinct electrophoretic properties after denaturation with formamide. RNA species with electrophoretic mobilities similar to those of the V200, V156, and V140 RNAs have been found in the cytoplasmic fraction of cells at late times after adenovirus infection. In isolated nuclei, the V200, V156, V140, and V130 RNAs are all synthesized by DNA-dependent RNA polymerase III, since synthesis is sensitive to high but not to low concentrations of alpha-amanitin. The synthesis of these low molecular weight RNAs continues for a prolonged period of time in isolated nuclei, suggesting that reinitiation occurs. Adenovirus 2 DNA fragments obtained by digestion with restriction endonucleases Eco RI and Sma I were used to map the location of the DNA sequences which encode the RNAs. All the low molecular weight RNAs hybridized to a region of the genome between o.18 and 0.38 fractional lengths from the left end of the adenovirus genome, suggesting that the respective DNA sequences are clustered. Other nonviral low molecular weight RNAs are synthesized in nuclei isolated from infected cells. These include the cellular 5S rRNA species which was minitored by its hybridization to purified 5S DNA from Xenopus laevis.     

Glutamate dehydrogenase activity in the structures of the rabbit brain limbic system

The activity of glutamate dehydrogenase (EC 1.41.1.3) is studied in homogenates and subcellular fractions of five limbic structures: regio superior, regio inferior of hippocampus, fascia dentata, septum and corpora mamillaria. The lowest activity of the enzyme is found in regio superior of hippocampus. 80% of the total enzyme activity of primary fractions is found in "crude" mitochondria. After centrifugation of the latter within the linear sucrose density gradient the distribution of the enzume activity is similar for different structures and the highest activity is found in the region of sucrose molarity from 1.44 up to 1.50 M which corresponds to the mitochondria distribution region. 50% of the total found activity is in the fraction enriched by mitochondria, 30% is in the fraction enriched by nerve endings with the high activity of glutamate decarboxylase. It was found for different fractions that 1 mM of ADF with 0.2 mM NAD-H+ produces about 10-fold increase in the enzyme activity. Pyridoxal-5'-phosphate inhibits the enzyme from inactivation. The results are discussed in connection with the possible role of pyridoxal-5'-phosphate in regulation of the glutamate dehydrogenase activity in vivo.     

Reinterpretation of luminiscence properties of neurotoxins from the venom of Middle-Asian corba Naja oxiana eichw

A new interpretation of previous work (Bukolova-Orlova, T. G., Burstein, E.A. and Yukelson, L. Ya (1974) Biochim. Biophys. Acta 342, 272-280) and some new data on the luminescence of neurotoxins I and II from Naja oxiana venom is given, based on the newer data on their complete amino acid sequences. Very effective excitation energy exchange exists between Trp-27 and Trp-33 in neurotoxin I and between Trp-27 and Trp-28 in neurotoxin II, Which results in the tryptophanyl fluorescence spectra of each of the proteins seeming to be monocomponent ones. The lowered fluorescence quantium yield value, the shortened phosphorescence lifetime (80% of the emission has tau p less than 0.5 s, 20% has tau p = 4.8 s, comparing with usual tau p = 5.5-5.9 s) and decreased phosphorescence to fluorescence ratio (0.042, as compared to the usual 0.4-0.7) for neurotoxin I suggest that the indole chromophore of Trp-27 and/or Trp-33 are in contact with heavy sulfur atoms of disulfide, most probably of Cys(28)-Cys(32). Tryptophanyls in neurotoxin II are exposed to the solvent, however their accessibility in relation to that of the free tryptophan to the negatively charged quencher I- (0.455) is much higher than that for the positively charged Cs+ (0.08), which is probably due to the proximity of cationic Lys-25, Lys-26 and His-31. The difference of accessibility to the negative and positive quenchers is even more pronounced in the case of the neurotoxin I (1.04 and 0 +/- 0.02, respectively), though in its chromophore vicinity along the primary structure there is only one cationic group, Lys-25. This fact together with the analysis of the amino acid sequence, suggest that the space folding of this polypeptide results in the close proximity of Trp-27 and/or Trp-33 with the C-terminal peptide segment 67-73, which contains four cationic groups (His-67, Lys-69, Lys-71 and Arg-72).     

Metabolic clearance and secretion rates of porcine growth hormone in genetically lean and obese swine

The metabolic clearance rate (MCR) and the secretion rate (SR) of porcine growth hormone (pGH) have been examined in swine rendered genetically either lean or obese after 18 generations of selection for or against backfat thickness. At 15 weeks of age (when the muscle:fat ratio was greater than 1) the mean half-life (t1/2), MCR, and SR, for the obese, control, and lean swine were: t1/2 = 7.4, 8.9, and 9.8 min; MCR = 341, 279, and 158 ml/min; SR = 907, 802, and 520 ng/min, respectively. At 90 kg body weight (when muscle:fat ratio was less than 1, and the age was about 30 weeks) the data for obese, control, and lean swine were: t1/2 = 11.3, 12.0, and 11.7 min; MCR =305, 280, and 336 ml/min; SR= 535, 626, and 932 ng/min, respectively. The t1/2, MCR, and SR were not significantly different among the obese, control, and lean swine at either 15 weeks or 90 kg body weight. Comparing the two stages of development, the younger swine (15 weeks of age) had a shorter t1/2 (P less than .01), and secreted and cleared more pGH on a per kg body weight basis (P less than .05) than the older swine (90 kg bodyweight, about 30 weeks of age). However, the results suggest that the selection of swine for either leanness or fatness for 18 generations did not alter the MCR and SR of pGH. In addition, the differences observed between the younger and older swine suggest that GH is cleared at a more rapid rate and more GH is available per unit of mass in the younger animals.     

A staging system for forelimb regeneration in the axolotl, Ambystoma mexicanum

A staging system has been devised for normal regeneration from the upper arm in the mature axolotl. It consists of seven externally definable stages: (1) Wound healing (WH): (2) Dedifferentiation (DD); (3) Early bud (EB); (4) Medium bud (MB); (5) Late bud (LB); (6) Palette (Pal), and (7) Digital outgrowth (DO). Serial histological sections of 38 regenerating limbs were used to correlate gross stages with microscopic events in the regenerative process.     

3-D-micro-ERDA microscopy of trace hydrogen distributions in diamond using a 2-D-PSD with event reconstruction

A fast-imaging technique for the total elemental hydrogen concentration distribution is described, which is helpful in the study of its chemistry and dynamics in the diamond system. The micro-scanned Heavy-Ion Elastic Recoil Detection Analysis (HI-ERDA) technique can deliver information on hydrogen distributions in three dimensions. In our system, the count rate is enhanced by use of a 2-D position and energy sensitive detector for the hydrogen recoils. Software geometry collimation and recoil energy rebinning ensure that the increased rate is in fact accompanied by an improvement in effective energy resolution. The system has been used to study the mobility and trapping behaviour of a collimated implant of hydrogen into a pre-damaged natural type IIa diamond sample as well as the mobility and trapping behaviour of collimated implants of hydrogen into diamond, which has not been pre-damaged.     

Behavioral instrumental reactions and the frequency of cardiac contractions in chimpanzees with different rates of approaching a goal and a shortened time of its exposure

Reaching the goals moving with different speed (from 1 to 400 mm/sec), the chimpanzee revealed respective behavioural, emotional, instrumental, and cardiovascular responses. When obscuring the goal for a certain time, the chimpanzee nevertheless managed to reach it, the relations between the speed of approaching goal and behavioural or instrumental responses being preserved. Thereupon, the chimpanzee are able to reach the goal provided the latter's trace exceeds 5-10-fold the time of really acting stimulus.