The mesokaryote Gyrodinium cohnii lacks nucleosomes.
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Biomedical subjects
Publications and source records attributed to D S Holmes.
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While waiting to receive electric shocks, 105 males either (a) regulated their breathing at one half the normal rate, (b) regulated their breathing at the normal rate, or (c) did not regulate their breathing rate. Half of the subjects in each breathing condition were told that their breathing task would aid them in relaxing, whereas the other half were not given that expectation. Subjects in a no threat condition were not threatened with shocks, did not regulate their breathing, and were not provided with expectations. The results indicated that slowing respiration rate reduced physiological arousal as measured by skin resistance and finger pulse volume (but not heart rate) and reduced self-reports of anxiety. Expectations did not influence arousal. These data provide evidence for the effectiveness of paced respiration as a coping strategy, and they resolve the conflicting findings of previous investigations.
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After a 30-minute rest period, (a) subjects in a respiration tracing condition began replicating their breathing patterns from the rest period; (b) subjects in an attention tracing condition participated in a comparable task that did not involve the control of respiration; and (c) subjects in a no-tracing condition were not assigned to perform any task. After the tracing manipulation was introduced, half of the subjects were assigned to a threat condition and informed that they would receive a series of painful electric shocks, whereas the other subjects were assigned to a no-threat condition and informed that they would receive red light stimulation. Analyses of heart rate and self-report data indicated that (a) the threat manipulation was effective; (b) controlling respiration did not reduce subjects' stress responses; and (c) subjects in the no-tracing condition were the only stressed subjects to show decreases in physiological arousal over time, an effect that may have been due to their use of a cognitive coping strategy (situation redefinition). These findings do not provide evidence that control of respiration is an effective strategy for controlling stress but do suggest that, when not interferred with, subjects can employ relatively effective, self-generated cognitive coping strategies.
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The positions of the several sea urchin histone genes on the eukaryotic fragments of the chimeric plasmids pSp2 and pSp17 have been mapped relative to the Eco RI and Hind III restriction endonuclease sites on the plasmids. Two principal mapping methods using the electron microscope have been used: (a) the R-loop procedure and a new modification thereof to map the genes on duplex DNA; (b) the gene 32-ethidium bromide technique to visualize RNA-DNA hybrids on single strands of DNA. It is known that there are two histone genes, H3 and H2A, on pSp17. There are two Eco RI sites at the two junctions of the procaryotic segment with the eucaryotic segment on the plasmid. We show, by an electron microscope method, that for H2A, with a length of 0.52 kilobases (kb), one end of the gene is situated 0.02 to 0.03 kb from one RI site, and that there is a Hind III site within this gene at about 0.13 kb from the end phe other RI site of this plasmid. The H4 gene lies between H2B and H1. The ms the incubation temperature is raised up to a temperature just below that at which strand dissociation of the duplex DNA occurs.
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A method of enriching for long double-stranded segments of eukaryotic DNA carrying particular genes is described. A purified RNA coded for by the gene is covalently attached to biotin via the protein, cytochrome c. This modified RNA is hybridized to total nuclear, double-stranded DNA under conditions that allow the formation of R-loops. Avidin, which has a high affinity for biotin, is covalently attached to polymer spheres. The complexes of avidin-spheres with DNA:RNA-biotin R-loop hybrids band in CsCl at a much lower bouyant density than does free DNA. This density is a function of the length of DNA coupled per avidin-sphere. This method was used to prepare very long double-strands of DNA highly enriched in the coding sequences for the large rRNAs of D. melanogaster and L. donovani and the histone mRNAs of S. purpuratus.
In a factorial experiment, 90 male and 90 female subjects were given (a) either instructions to increase heart rate (HR), decrease HR, or no instructions to change their HR; (b) either true biofeedback, false biofeedback, or no biofeedback; and (c) either instructions concerning cognitions to help them change HR or no instructions concerning cognitions. The results indicated that (a) for increasing HR, instructions to increase HR were as effective as the combination of instructions and true biofeedback; (b) for decreasing HR, neither instructions nor biofeedback nor the combination of instructions and biofeedback was more effective than simply sitting quietly; (c) although subjects instructed to increase HR showed higher HRs at the end of training than subjects instructed to decrease, the increase subjects showed a decline in HR from the initial period; (d) almost all subjects reported using cognitions to influence HR, and instructions concerning the use of cognitions did not facilitate changes in HR; and (e) women showed higher HRs, which declined more slowly than those of men, but sex did not interact with any treatment variable. It was concluded that increases (or retarded decreases) in HR were due to instructions, and decreases were due to simple adaptation, thus raising serious questions concerning the effectiveness of the biofeedback component of "biofeedback training" for altering HR.
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The relative positions of the sea urchin histone genes and the spacer regions on the chimeric plasmids pS p2 and pSp17 have been mapped by hybridizing total histonemessenger RNA to single strands of the plasmid DNAs. The lengths and spacing between the several RNA:DNA duplex regions on the single strands of DNA were measured by the gene 32-ethidium bromide electron microscope mapping method. We find that the genes are interdigitated with spacer sequences of different lengths; that there are three coding sequences on pSp2, all on the same strand, with the relative order H1, H4, and B4; and that there are two coding sequences on pSp17, both on the same strand, corresponding to the messages denoted B1 and B2-B3, where B4, B1, and B2-3 are electrophoretically resolved components of histone mRNA, all of size intermediate between the larger H1 and the smaller H4 message.
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Subjects in a threat condition were informed that they had failed an important test while subjects in a nonthreat condition were not told that they had failed. To manipulate the use and timing of coping strategies for dealing with threat, subjects were told to (a) redefine the nature and importance of the test before receiving feedback, (b) redefine the nature and importance of the test after feedback, or (c) estimate the performance of their friends on the test (i.e., project) after receiving feedback. Repeated measures of subjective anxiety and pulse rate indicated that (a) the threat manipulation was effective in increasing stress, (b) redefinition occurring before the onset of threat was effective in eliminating stress, and (c) redefinition occuring after the onset of threat was ineffective in reducing stress. Projection reduced the report of subjective anxiety. The results revealed factors that influence coping strategy effectiveness and resolved conflicts in previous findings.
Ninety-six subjects with either high or low I-E Scale scores participated in individual discussions with an experimental who either (a) rewarded and then punished, (b) punished and then rewarded, or (c) gave no evaluative feedback after the subject's responses. Because previous research has suggested that internally controlled subjects attend primarily to rewards while externally controlled subjects attend primarily to punishments, it was hypothesized (a) that the internally controlled subjects, as compared to externally controlled subjects, would be more attracted to the experimenter in the conditions involving rewards and punishments regardless of the sequencing and (b) that the reverse would be true in the nonevaluative control condition. The prediction was consistently supported and subjects' feelings of anger and anxiety during the discussions generally complemented the attention and attraction hypotheses. The results indicate that individual differences influence attraction in situations involving rewards and punishments and they offer a prescription for developing interpersonal attraction and minimizing anger: Offer rewards to internally controlled persons and remain neutral with externally controlled persons.
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