Adaptation of Phytoplankton-Degrading Microbial Communities to Thermal Reactor Effluent in a New Cooling Reservoir

In water column and sediment inocula from a nuclear reactor cooling reservoir, natural phytoplankton substrate labeled with ¹⁴C was used to determine aerobic and anaerobic mineralization rates for a range of temperatures (25, 40, 55, and 70°C) expected during reactor operation. For experiments that were begun during reactor shutdown, aerobic decomposition occurred at temperatures of <55°C. After 2 months of reactor operation, aerobic rates increased substantially at 55 and 70°C, although maximum rates were observed at temperatures of ≤40°C. The temperature range for which maximum anaerobic mineralization (i.e., the sum of CH₄ and CO₂) was observed was 25 to 40°C when the reactor was off, expanding to 25 to 55°C during reactor operation. Increased rates at 55°C, but not 70°C, correlated with an increase in the ratio of cumulative methane to carbon dioxide produced over 21 days. When reduced reactor power lowered the maximum temperature of the reservoir to 42°C, aerobic decomposition at 70°C was negligible, but remained substantial at 55°C. Selection for thermophilic decomposers occurred rapidly in this system in both aerobic and anaerobic communities and did not require prolonged exposure to elevated temperatures.     

Cloning and characterization of a linear 2.3 kb mitochondrial plasmid of maize

Summary A linear 2.3 kb DNA molecule found in maize mitochondria was cloned into pUC8. A natural deletion of this plasmid, found in cmsT and some N (fertile) types of maize plants, was mapped to one end of the plasmid. A minor sequence homology to S-2, another linear mitochondrial plasmid, was detected, as well as more significant sequence homology with chloroplast and maize nuclear DNA. Hybridization to teosinte mitochondrial DNA (mtDNA) revealed the presence of part of the maize plasmid in the high molecular weight mtDNA of the maize relatives. RNA dot hybridization indicates that the plasmid is transcribed in mitochondria. The termini of the 2.3 kb linear plasmid contain inverted repeated sequences; of the first 17 nucleotides of the termini, 16 are identical to the terminal inverted repeats of the linear S plasmids found in the mitochondria of cmsS maize plants.     

Biofeedback,voluntary control,and human potential

This paper examines some of the philosophical and scientific relationships involving self-control, voluntary control, and psychophysiologic self-regulation. The role of biofeedback in mediating conscious and unconscious processes is explored. Demonstrations of superior voluntary control and its relationship to belief, confidence, and expectation are examined. Biofeedback demonstrates the potential of control to oneself, creating confidence in one's ability to establish enhanced and peak performance in athletics, education, and psychophysiologic therapy. Emphasis is placed on the power of images in all human functioning, and in enhancing human potential.Presidential address presented at the meetings of the Biofeedback Society of America, March 23, 1986, San Francisco.     

Comparison of glucokinase in C3H/He and C58 mice that differ in their hepatic activity

Partially purified preparations of the hepatic glucokinase from C3H/He and C58 inbred mice have been used to explore the molecular basis for the observed twofold difference in activity between the strains. The single codominant gene that appears to regulate activity, the alleles of which are designated Gk^a and Gk^b, respectively, for the two strains, could represent a structural gene change. This now seems unlikely because the mouse enzyme, although showing small differences from rat glucokinase, appeared to be identical in the two strains with respect to thermal stability, electrophoretic mobility in agarose gels, and kinetic properties such as the apparent K _m values for MgATP^2– and glucose and the unique cooperative interaction with the latter substrate. The enzymes also reacted identically in a range of immunological tests (double-diffusion, immunoelectrophoresis, immune precipitation and immune inhibition assays) and ELISA immune inhibition assays indicated that the twofold difference in activity was due to a similar difference in antigenically active enzyme. Genetic control over the physiologically significant regulation of enzyme amount is therefore probable.This work has been supported in part by a grant from the British Diabetic Association and a Training Studentship to PAJ from the Medical Research Council (U.K.).     

Adaptation to High-Intensity, Low-Wavelength Light among Surface Blooms of the Cyanobacterium Microcystis aeruginosa

Natural populations of the nuisance bloom cyanobacterium Microcystis aeruginosa obtained from the eutrophic Neuse River, N.C., revealed optimal chlorophyll a-normalized photosynthetic rates and resistance to photoinhibition at surface photosynthetically active radiation (PAR) intensities. At saturating PAR levels these populations exhibited higher photosynthetic rates in quartz than in Pyrex vessels. Eucaryotic algal populations obtained from the same river failed to counteract photoinhibition. At saturating PAR levels, such populations generally yielded lower photosynthetic rates in quartz containers than they did in Pyrex containers. Cultivation of natural Microcystis populations under laboratory conditions led to physiologically distinct populations which had photoinhibitory characteristics similar to those of other cultured cyanobacterial and eucaryotic algae. Our findings indicate that (i) photosynthetic production among natural surface populations is best characterized and quantified in quartz rather than Pyrex incubation vessels; (ii) extrapolation of natural photoinhibitory trends from laboratory populations is highly subjective to culture and PAR histories and may yield contradictory results; and (iii) buoyant surface-dwelling populations, rather than exhibiting senescence, are poised at optimizing PAR utilization, thereby maintaining numerical dominance in eutrophic waters when physico-chemical conditions favor bloom formation.     

Preliminary crystallographic data for cross-linked (lysine7-lysine41)-ribonuclease A

A cross-linked derivative of ribonuclease A, N^ε,N^ε′-(2,4-dinitrophenylene-1,5)-(lysine⁷-lysine⁴¹)-RNase A, has been crystallized by dialysis against 30% ($\text{v}\text{v}$) ethanol/water mixtures buffered at high pH. Single crystals belong to the orthorhombic space group P2₁2₁2₁, $\text{a = 37.2}\text{A}\text{?}\text{, b = 41.2}\text{A}\text{?}\text{, b = 41.2}\text{A}\text{?}$, with one molecule in the Crystallographic asymmetric unit.     

Heterologous hybridization of Azospirillum DNA to Rhizobium nod and fix genes

Abstract Probes containing the nod and hsn regions of Rhizobium meliloti and the fixABC genes of Rhizobium japonicum were used to perform hybridization experiments with endonuclease-restricted DNA from Azospirillum brasilense strains and 2 Azospirillum lipoferum strains. Homology to nod, hsn and fixA was found in the 4 Azospirillum strains.     

Reduction in headache patients' medical expenses associated with biofeedback and relaxation treatments

Comparisons are made of self-reported medical costs from a sample of headache patients who underwent various combinations of relaxation training and biofeedback training. The average costs for the 2 years prior to self-regulatory treatment were $955±480 (3 SEM) for 45 patients; for the 2 years after completing treatment the average costs were $52±28 (3 SEM) for patients. Within the limitations of the study, medical costs do seem to have been markedly reduced.This research was supported by a grant from NINCDS, NS-15235.