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PubMed1995

Regulation of Photosynthetic Induction State in High- and Low-Light-Grown Soybean and Alocasia macrorrhiza (L.) G. Don.

Alocasia (Alocasia macrorrhiza [L.] G. Don) and soybean (Glycine max [L.]) were grown under high or low photon flux density (PFD) conditions to achieve a range of photosynthetic capacities and light-adaptation modes. The CO2 assimilation rate and in vivo linear electron transport rate (Jf) were determined over a range of PFDs and under saturating 1-s-duration lightflecks applied at a range of frequencies. At the same mean PFD, the assimilation rate and the Jf were lower under the lightfleck regimes than under constant light. The activation state of two, key enzymes of the photosynthetic carbon reduction cycle pathway, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and fructose-1,6-bisphosphatase, and the photosynthetic induction states (ISs) were also found to be lower under flashing as compared to continuous PFD. Under all conditions, the IS measured 120 s after an increase in PFD to constant and saturating values was highly correlated with the Rubisco activation state and stomatal conductances established in the light regime before the increase. Both the fructose-1,6-bisphosphatase and Rubisco activities established in a particular light regime were highly correlated with the mean Jf in that regime. The relationships between enzyme activation state and Jf and between IS and enzyme activation state were similar in soybean and Alocasia and were not affected either by growth-light regime, and hence photosynthetic capacity, or by flashing versus constant PFD. The common relationship between the linear Jf and the activation state of key enzymes suggests that electron transport may be the determinant of the signal regulating IS, at least to the extent that the IS is controlled by the activation state of key stromal enzymes.

Journal Article↗

PubMed2005

Design and psychometric evaluation of the Psychological Adaptation to Genetic Information Scale.

PURPOSE: To develop and psychometrically evaluate the Psychological Adaptation to Genetic Information Scale (PAGIS). DESIGN: A cross-sectional, Web-based survey of participants (n=323) recruited via Internet electronic mailing lists or Websites for people affected by genetic diseases. METHODS: Item analysis, confirmatory principal components analysis, and internal consistency reliability using Cronbach's alpha were used to construct the 26-item PAGIS. FINDINGS: Five factors (nonintrusiveness, support, self-worth, certainty, and self-efficacy) explained 57.7% of the variance in psychological adaptation to genetic information. The internal consistency reliability of the total PAGIS was .90, and the subscale reliabilities ranged from .77 to .87. CONCLUSIONS: Psychological adaptation to genetic information is a multidimensional phenomenon comprised of nonintrusiveness, support, self-worth, certainty, and self-efficacy. The PAGIS has initial reliability and validity for use in future research.

Adaptation, Psychological↗

PubMed2005

Rotational motion changes in the glenohumeral joint of the adolescent/Little League baseball player.

BACKGROUND: Differences in range of motion and rotational motion between the dominant and nondominant shoulders in throwing athletes are well documented, although the age at which these changes begin to occur is not known. HYPOTHESIS: Changes in glenohumeral rotational motion in the shoulder of the Little League/adolescent baseball player occur during the most formative years of physical development. STUDY DESIGN: Cross-sectional study. METHODS: Elevation, internal rotation at 90 degrees of abduction, and external rotation at 90 degrees of abduction were measured in the dominant and nondominant shoulders of 294 baseball players, aged 8 to 16 years. RESULTS: Analysis of variance revealed 2-way interactions between arm dominance by age for elevation (P = .005) and internal rotation (P = .001). Significant differences were noted between dominant and nondominant arms for internal rotation at 90 degrees (P = .001) and external rotation at 90 degrees (P = .001). Elevation, internal rotation at 90 degrees , external rotation at 90 degrees , and total range of motion varied significantly (P = .001) among age groups. Elevation in the dominant arms of 16-year-olds was on average 5.3 degrees less than in 8-year-olds (179.6 degrees vs 174.3 degrees ). In the nondominant arms, mean elevation for 16-year-olds was 5.6 degrees less than in 8-year-olds (179.7 degrees vs 174.1 degrees ). Internal rotation at 90 degrees for the dominant arms averaged 39.0 degrees at age 8 and only 21.3 degrees at age 16. In the non-dominant arms, internal rotation for 8-year-olds averaged 42.2 degrees and only 33.1 degrees for 16-year-olds. CONCLUSIONS: Elevation and total range of motion decreased as age increased. These changes may be consequences of both bone and soft tissue adaptation. The most dramatic decline in total range of motion was seen between the 13-year-olds and 14-year-olds, in the year before peak incidence of Little Leaguer's shoulder. This decrease in rotational motion may cause increased stress at the physis during throwing.

Adolescent↗

PubMed2005

Intellectual abilities and adaptive behavior of children and adolescents with Kabuki syndrome: a preliminary study.

Very little is known about the intellectual abilities and adaptive behavior of individuals who have Kabuki syndrome, beyond the fact that most individuals with this syndrome have mental retardation. To fill this gap, we have completed psychological assessments of 11 children and adolescents with Kabuki syndrome. Results indicated that most of the participants functioned in the range of mild mental retardation, with both intellectual and adaptive behavior in the mildly deficient range and problem behaviors, if any, limited to mild difficulties with inattention and/or hyperactivity-impulsivity and mild problems with obsession/anxiety. At the lower extreme, one child evidenced severe mental retardation and profound adaptive behavior impairment accompanied by serious externalizing and internalizing problem behaviors. At the upper extreme, one adolescent had average intelligence and adaptive behavior, with problem behaviors well within the normal range for his chronological age. Most participants evidenced relative intellectual strengths in verbal and reasoning abilities and a relative weakness in visuospatial construction abilities. This pattern affected adaptive behavior as well, yielding a relative strength in Social Interaction and Communicative Skills and considerable weakness in Motor Skills and Personal Living Skills.

Abnormalities, Multiple↗

PubMed2005

The motion aftereffect of transparent motion: two temporal channels account for perceived direction.

Adaptation to orthogonal transparent patterns drifting at the same speed produces a unidirectional motion aftereffect (MAE) whose direction is opposite the average adaptation direction. If the patterns move at different speeds, MAE direction can be predicted by an inverse vector average, using the observer's motion sensitivity to each individual pattern as vector magnitudes. These weights are well approximated by the duration of each pattern's MAE, as measured with static test patterns. However, previous efforts to use the inverse-vector-average rule with dynamic test patterns have failed. Generally, these studies have used spatially and temporally broadband test stimuli. Here, in order to gain insight into the possible contribution of temporal channels, we filtered our test pattern in the temporal domain to produce five ideal, octave-width pass-bands. MAE durations were measured for single-component stimuli drifting at various adaptation speeds and tested at a range of temporal frequencies. Then, two components with orthogonal directions and different speeds were combined and the direction of the resulting MAE was measured. The key findings are that: (i) for a given adaptation speed, the duration of a single component's MAE is dependent on test temporal frequency; (ii) the direction of MAEs produced by transparent motion (i.e., bivectorial adaptation) also varies strongly as a function test temporal frequency (by up to 90 degrees for some speed pairings); and (iii) the inverse-vector-average rule predicts the direction of the transparent MAE provided the MAE durations used to weight the vector combination were obtained from stimuli matched in adaptation speed and test temporal frequency. These results are discussed in terms of the number and shape of temporal channels in our visual system.

Adaptation, Physiological↗

PubMed2001

A novel replication element from an Antarctic plasmid as a tool for the expression of proteins at low temperature.

Genetic manipulation of Antarctic bacteria has been very limited so far. This article reports the isolation and molecular characterization of a novel plasmid, pMtBL, from the Antarctic gram-negative bacterium Pseudoalteromonas haloplanktis TAC 125. This genetic element, 4,081 bp long, appeared to be a multicopy cryptic replicon with no detectable transcriptional activity. By an in vivo assay, the pMtBL autonomous replication sequence was functionally limited to an AluI plasmid fragment of about 850 bp. This novel cold-adapted replication element showed quite a broad host range profile: it was cloned into a mesophilic genetic construction, obtaining a cold-adapted expression vector that was able to promote the production of P. haloplanktis A23 alpha-amylase in a psychrophilic bacterium. This study represents the first report of successful recombinant production of a cold-adapted protein in an Antarctic host.

Antarctic Regions↗

PubMed1997

Adaptation to optokinetic rotation-induced motion sickness without experiencing nausea.

17 subjects highly susceptible to motion sickness were divided into Nausea and No-nausea groups depending upon whether the subjects experienced nausea during adaptation to nauseagenic rotation. Eight subjects in the Nausea group viewed an optokinetic rotation drum for repeated sessions of 16 min., with an interval of two days between every two sessions. During each session the subjects continuously viewed the rotating drum 16 min. even if they experienced nausea. nine subjects in the No-nausea group likewise viewed an optokinetic rotation drum for at most 16 min. but immediately stopped viewing the rotating drum whenever they experienced nausea during the session. The criteria for full adaptation were that the subject reported no feelings of stomach discomfort and nausea during a 16-min session. The mean number of sessions to reach full adaptation was 3.9 (SD = 0.6) with a range 3 to 5 sessions for the subjects in the Nausea group and 3.2 (SD = 0.8) with a range 2 to 4 for the subjects in the No-nausea group. It was concluded that subjects can adapt to a nauseagenic optokinetic rotation by repeated exposure without experiencing nausea and vomiting during adaptation.

Adaptation, Physiological↗

PubMed1995

Physiological properties of wind-sensitive and tactile trichoid sensilla on the ovipositor and their role during oviposition in the locust

The physiological properties of the ovipositor hair sensilla of the desert locust and their responses to wind and to direct mechanical displacement are described. The hairs on the external surfaces of the ventral and dorsal ovipositor valves respond to wind stimulation, whereas the hairs on the inner surfaces of the dorsal valves are not wind-sensitive. All ovipositor hairs, however, respond to tactile displacement. Imposed tactile stimulation reveals two physiologically distinct types of ovipositor tactile hairs: the hairs on the inner surface of the dorsal valves are high-threshold hairs (threshold angular deflection of 2667 ° at 1 Hz) that respond phasically, whereas the hairs on the lateral and ventral areas of the ventral valves and the lateral areas of the dorsal valves are low-threshold hairs (threshold angular deflection of 620 ° at 1 Hz) that respond phasotonically. There is no apparent difference in the length of the two physiologically distinct types of hairs. Both high- and low-threshold hairs are directionally sensitive, with maximal responses to proximal deflection, towards the abdomen, and are also velocity-sensitive. High-threshold hairs have velocity thresholds of 4050 ° s-1 for some hairs and 110140 ° s-1 for others for a deflection angle of 35 °, whereas low-threshold hairs have lower velocity thresholds of less than 5 ° s-1 for the same deflection. High-threshold hairs adapt rapidly to repetitive stimulation after as few as four cycles of stimulation at 0.5 Hz. Low-threshold hairs continue to respond after 40 cycles of stimulation at 0.5 Hz and show little adaptation to repetitive stimulation at frequencies ranging from 0.1 to 5 Hz. Low-threshold hairs respond with bursts of spikes at frequencies that reflect both the velocity and the duration of the stimulus. Furthermore, low-threshold hairs show little adaptation after 30 min of stimulation that simulates oviposition digging. It is suggested (a) that low- and high-threshold ovipositor hairs detect phasic wind and/or tactile stimuli in non-ovipositing locusts and (b) that low-threshold hairs can also signal rhythmic tactile inputs during oviposition digging.

Journal Article↗

PubMed1977

Electroencephalographic correlates of prism adaptation in mentally retarded individuals.

Sensorimotor adaptation was studied in 23 institutionalized, mentally retarded individuals. This was achieved by recording the pattern of off-target pointing errors resulting from viewing through a 20-diopter prism. The results showed a wide range of individual differences in prism adaptation. The electroencephalogram (EEG) was also recorded from four scalp locations and analyzed by computer to determine EEG intensity, coherence, and phase angle. Correlations between EEG and behavioral scores of prism adaptation revealed a number of significant relationships, especially negative correlations between alpha intensity and prismatic adaptation. These results indicate that patterns of central nervous system activity are meaningful related to sensorimotor capabilities in retarded individuals.

Adaptation, Physiological↗

PubMed2006

Human cone light adaptation: from behavioral measurements to molecular mechanisms.

The ability of the cone visual system to regulate its sensitivity from twilight to bright sunlight is an extraordinary feat of biology. Here, we investigate the changes in visual processing that accompany cone light adaptation over a 5 log10 unit intensity range by combining measures of temporal sensitivity made in one eye with measures of the temporal delay between the two eyes in different states of adaptation. This combination of techniques, which provides more complete information than has been available before, leads to a simple model of steady-state light adaptation. At high light levels, visual sensitivity is maintained mainly by photopigment bleaching. At low-to-moderate light levels, it is maintained by trading unwanted sensitivity for speed and by an additional process that paradoxically increases the overall sensitivity as the light level rises. Each stage of the model can be linked to molecular mechanisms within the photoreceptor: The speeding up can be linked to faster rates of decay of activated molecules; the paradoxical sensitivity increases can be linked to faster rates of molecular resynthesis and to changes in channel sensitivity; and the sensitivity decreases can be linked to bleaching. Together, these mechanisms act to maintain the cone visual system in an optimal operating range and to protect it from overload.

Adaptation, Ocular↗

PubMed1997

Cognitive, adaptive, and behavioral characteristics of Williams syndrome.

Williams syndrome is a genetic disorder linked to cognitive and behavioral patterns of varying consistency; this study was conducted to clarify further the strengths and weaknesses of children with Williams syndrome. Fifteen subjects with the characteristic features of Williams syndrome were evaluated using the Stanford-Binet Intelligence Scale for Children, Fourth Edition; the Vineland Adaptive Behavior Scales, Interview Edition; and the Child Behavior Checklist. Cognitive skills ranged from the Moderate Range of Mental Retardation to the Low Average range, with relative strengths in nonverbal and quantitative reasoning. Adaptive skills were delayed, with strengths in communication and socialization. Behaviorally, clinically significant levels of attention problems, borderline-significant levels of social and thought problems, and significantly low levels of social contacts and structured activities were found. In contrast to the findings of many other studies of Williams syndrome, language skills and short-term memory skills were weak. Children with Williams syndrome may present a more evenly developed intellectual profile, with verbal and nonverbal skills being commensurate. In conclusion, a variety of cognitive, adaptive, and behavioral patterns have been shown to be possible in Williams syndrome; therefore, a single predictable cognitive or behavioral phenotype cannot be assumed.

Activities of Daily Living↗

PubMed2003

Interspecific variations in the morphology and ultrastructure of the rhabdoms of oplophorid shrimps.

Interspecific variations in rhabdom structure between various oplophorid shrimps are described and the differences are related to the light environment at different depths within the mesopelagic zone. The ultrastructure of the distal rhabdom in these species is described for the first time. Quantitative measurements show that the proportion of the rhabdom layer occupied by the distal rhabdom varies from 3.5-25% in the dorsoventral plane of the eye of Systellaspis debilis. The distal rhabdom occupies less than 1% of the rhabdoms in the eye of Acanthephyra pelagica, where it can only be seen by using the electron microscope. It is suggested that the rhabdoms of those species that remain within the photic zone (such as S. debilis) are adapted to maximize contrast, whereas in those whose depth ranges extend into the aphotic zone (such as A. pelagica) they are adapted for maximum sensitivity.

Adaptation, Biological↗

PubMed1991

Sex differences in finger temperature response to music.

A finding of significant sex differences in finger temperature responses to stimuli would have implications for a variety of situations in which finger temperature changes in combination with other psychophysiological measures are employed as indicators of psychological and/or physiological states. In the present study, each subject listened to one of two distinct musical selections for 3-minutes and 40-seconds after being allowed to adapt for one of five durations ranging from 4 to 20 minutes. Females' finger temperatures decreased more or increased less than did males' finger temperatures. This finding held no matter which music was played and was true for all but the shortest adaptation duration. Control data indicated that the sex difference would not have occurred in the absence of the music, and thus the results suggest that females' finger temperatures decrease more than males' only when stimulation occurs. Possible causes of the sex difference are discussed as well as possible implications for studies in which finger temperature is employed as a dependent variable.

Adaptation, Physiological↗

PubMed2005

The halophilic fungus Hortaea werneckii and the halotolerant fungus Aureobasidium pullulans maintain low intracellular cation concentrations in hypersaline environments.

Hortaea werneckii and Aureobasidium pullulans, black yeast-like fungi isolated from hypersaline waters of salterns as their natural ecological niche, have been previously defined as halophilic and halotolerant microorganisms, respectively. In the present study we assessed their growth and determined the intracellular cation concentrations of salt-adapted and non-salt-adapted cells of both species at a wide range of salinities (0 to 25% NaCl and 0 to 20% NaCl, respectively). Although 5% NaCl improved the growth of H. werneckii, even the minimal addition of NaCl to the growth medium slowed down the growth rate of A. pullulans, confirming their halophilic and halotolerant nature. Salt-adapted cells of H. werneckii and A. pullulans kept very low amounts of internal Na+ even when grown at high NaCl concentrations and can be thus considered Na+ excluders, suggesting the existence of efficient mechanisms for the regulation of ion fluxes. Based on our results, we can conclude that these organisms do not use K+ or Na+ for osmoregulation. Comparison of cation fluctuations after a hyperosmotic shock, to which nonadapted cells of both species were exposed, demonstrated better ionic homeostasis regulation of H. werneckii compared to A. pullulans. We observed small fluctuations of cation concentrations after a hyperosmotic shock in nonadapted A. pullulans similar to those in salt-adapted H. werneckii, which additionally confirmed better regulation of ionic homeostasis in the latter. These features can be expected from organisms adapted to survival within a wide range of salinities and to occasional exposure to extremely high NaCl concentrations, both characteristic for their natural environment.

Adaptation, Physiological↗

PubMed1997

Thermally regulated translational control of FRQ mediates aspects of temperature responses in the neurospora circadian clock.

Two forms of FRQ, a central component of the Neurospora circadian clock, arise through alternative in-frame initiation of translation. Either form alone suffices for a functional clock at some temperatures, but both are always necessary for robust rhythmicity. Temperature regulates the ratio of FRQ forms by favoring different initiation codons at different temperatures; when either initiation codon is eliminated, the temperature range permissive for rhythmicity is demonstrably reduced. This temperature-influenced choice of translation-initiation site represents a novel adaptive mechanism that extends the physiological temperature range over which clocks function. Additionally, a temperature-dependent threshold level of FRQ is required to establish the feedback loop comprising the oscillator. These data may explain how temperature limits permissive for rhythmicity are established, thus providing a molecular understanding for a basic characteristic of circadian clocks.

Biological Clocks↗

PubMedDate not supplied

Salivary testosterone concentration of Aymara men native to 3600 m.

This paper explores the possibility that variation in the normal physiological range of testosterone concentration modulates men's adaptation to hypobaric high-altitude hypoxia through stimulating haemoglobin production and/or causing respiratory disturbances and exacerbated hypoxaemia during sleep. These effects of testosterone are observed clinically at sea level and have potentially opposing consequences at high altitude, the former perhaps enhancing and the latter diminishing the effectiveness of adaptations to hypoxia. Seventeen young (average age 27 years) and 22 older (average age 57 years) healthy adult high altitude native Aymara men tested at 3600 m have average morning salivary testosterone concentrations of 282 and 241 pmol/l, respectively. The 31 urban men of both age groups have higher testosterone concentrations than the eight rural men and have mean haemoglobin concentrations significantly 0.7-1.0 g/dl higher within the normal high-altitude range, consistent with known effects of testosterone at sea level. Older urban men have slightly more frequent respiratory disturbances during sleep, associated with significantly greater hypoxaemia. There appear to be modest benefits to testosterone concentrations in the upper end of the observed range; however, the direction of these responses towards more haemoglobin production and more hypoxaemia during sleep of older men suggests the hypothesis that very high testosterone concentrations such as those in the upper ranges of sea level values could compromise adaptation to high altitude, particularly among older men.

Adult↗

PubMed1989

Photoaversion in retinitis pigmentosa.

Photoaversion, or light-induced interference with visual comfort and performance, has been a recognised but poorly documented symptom in retinitis pigmentosa (RP). We found that a majority of our RP patients complained of photoaversion even in the absence of significant cataract. RP patients had reduced contrast sensitivity relative to normal people, but the decrement in their visual performance as a result of glare or photostress was only slight. RP patients had raised short-term adaptation and increment threshold levels, but their rate of short-term or photopic adaptation was normal. Photoaversion in RP may result because a small interference with contrast sensitivity or adaptation can place patients in a range of functional disability, or it may derive from a combination of minor aberrations.

Adaptation, Ocular↗

PubMed1979

Salinity adaptation in the snake eel Pisoodonophis boro (Ham-buch).

The snake eel Pisoodonophis Boro (Family Ophichthidae) burrows, causing leaks in the bunds and damaging the salterns and paddy fields adjoining estuaries. The animal's capability to withstand brine in salterns and fresh water in paddy fields was determined from laboratory experiments. The eel tolerated salinities ranging from deionized water to 75%. Adaptation to fresh water as well as full strength seawater was completed within 24 h. The concentration of sodium and chloride in the blood varied by 10--20% on transfer from seawater to fresh water. P. boro can survive in paddy fields but not in salterns. However, their occurrence in both is described as a rare phenomenon and not obligatory.

Adaptation, Physiological↗