We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads w... more We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads w... more We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
Joperd Journal of Physical Education Recreation and Dance, 1998
Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two... more Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference. - Robert Frost (Frost, 1916) Traditio.
In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visua... more In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visual input but on alternate days and for unequal periods. It has been shown previously that this imbalance in stimulation produces a deficit in the nasal visual field of the less experienced eye (LEE). The effect of subsequent binocular exposure on these visual deficits has now been examined. No evidence of recovery was found. Instead, visual fields remained the same or became smaller. In cats reared with little or no imbalance (8 hr/day vs 7 hr/day or 1 hr/day vs 1 hr), subsequent binocular exposure had no effect on visual fields. In cats reared with a moderate or large imbalance (8 hr/day vs 4 hr/day or 8 hr/day vs 1 hr/day), subsequent binocular exposure led to a suppression of the LEE: when tested binocularly, these cats rarely responded to targets presented in the monocular field of the LEE. The deficits became progressively more severe throughout the period of binocular exposure, unti...
ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a st... more ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a standard laboratory 12:12 LD photoperiod, a large diurnal peak of activity is revealed that is continuous with the E peak seen in constant dark (DD). We further show that the circadian clock gene tim regulates light-dependent masking of daytime activity, but the clock gene per does not. Finally, relative to wild-type flies, mutants for both of these clock genes showed increased nighttime activity in the skeleton photoperiod but not in the standard photoperiod. This result suggests that nighttime activity is suppressed by the intact circadian clock, and in its absence, by exposure to a standard photoperiod. These results support and extend the literature addressing the complex interactions between masking and clock-controlled components of overt circadian rhythms.
Page 103. Tunable Seers Activity-Dependent Development of Vision in Fly and Cat HELMUT VB HIRSCH,... more Page 103. Tunable Seers Activity-Dependent Development of Vision in Fly and Cat HELMUT VB HIRSCH, SUZANNAH BLISS TIEMAN, MARTIN EARTH, AND HELEN GHIRADELLA INTRODUCTION Programs guiding nervous system development must achieve two goals. ...
To test whether visual experience can affect development of visual behavior in the fruitfly, Dros... more To test whether visual experience can affect development of visual behavior in the fruitfly, Drosophila, we measured the visually-guided choice behavior of groups of flies reared in complete darkness, compared with controls reared in a normal light/dark cycle. We used a simple visual preference test, i.e. choice among four different visual targets each consisting of vertical black lines of a particular width on a white background, using a blind testing procedure so that the individual rearing histories were not known by the tester. Both groups of flies were strongly attracted to the vertical lines; however, generally the dark-reared flies were more attracted to the wider stimulus lines than were the control flies. Control experiments in which normally reared adults were kept for several days in darkness showed that the effects of dark-rearing were not simply due to being in darkness, but depended upon the timing of the deprivation. The results indicate that the development of visual behavior can be affected by visual experience in Drosophila and thus open the possibility of using Drosophila for genetic dissection of mechanisms of visual plasticity.
ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical o... more ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical overview of the biology of neuroplasticity. Environmental enrichment, social stimulation, exercise, and pharmacologic interventions (eg, antidepressant drugs) have all been reported to influence neuroplasticity. Since adaptive changes in the brain involve changes in how genes are expressed, we look at some approaches to that. Next, we consider a vital, but often overlooked, factor in brain development throughout life—social interactions. We conclude with a future perspective.
Kittens were reared so that each eye received normal patterned vision on alternate days. If the e... more Kittens were reared so that each eye received normal patterned vision on alternate days. If the eyes received equal periods of stimulation, the visual fields were normal. If one eye received much more experience than the other, the field of the less experienced eye was restricted to the temporal hemifield. This change, which differs from that observed when one or both eyes are deprived continuously of patterned input, suggests that an imbalance in the duration of stimulation can influence the outcome of the normal competitive interaction between pathways from the two eyes and can cause a selective suppression of a portion of the input from the less experienced eye. This suppression may involve the ipsilateral retino-geniculo-cortical pathways or it may involve the entire cortical pathway from the less experienced eye, leaving the colliculus to control responses to visual targets.
Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing ... more Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing radiation on human beings which do not produce any short-term effects, can serve as exemplification of (a) the existing trend of growing political integration of science and ...
We present data on the effects of various concentrations of the organophosphorus insecticide, fen... more We present data on the effects of various concentrations of the organophosphorus insecticide, fenitrothion, on development, reproduction and eggshell structure of Spodoptera exigua. The insecticide did not change the male/female ratio in tested populations. The ...
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads w... more We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads w... more We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
Joperd Journal of Physical Education Recreation and Dance, 1998
Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two... more Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference. - Robert Frost (Frost, 1916) Traditio.
In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visua... more In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visual input but on alternate days and for unequal periods. It has been shown previously that this imbalance in stimulation produces a deficit in the nasal visual field of the less experienced eye (LEE). The effect of subsequent binocular exposure on these visual deficits has now been examined. No evidence of recovery was found. Instead, visual fields remained the same or became smaller. In cats reared with little or no imbalance (8 hr/day vs 7 hr/day or 1 hr/day vs 1 hr), subsequent binocular exposure had no effect on visual fields. In cats reared with a moderate or large imbalance (8 hr/day vs 4 hr/day or 8 hr/day vs 1 hr/day), subsequent binocular exposure led to a suppression of the LEE: when tested binocularly, these cats rarely responded to targets presented in the monocular field of the LEE. The deficits became progressively more severe throughout the period of binocular exposure, unti...
ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a st... more ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a standard laboratory 12:12 LD photoperiod, a large diurnal peak of activity is revealed that is continuous with the E peak seen in constant dark (DD). We further show that the circadian clock gene tim regulates light-dependent masking of daytime activity, but the clock gene per does not. Finally, relative to wild-type flies, mutants for both of these clock genes showed increased nighttime activity in the skeleton photoperiod but not in the standard photoperiod. This result suggests that nighttime activity is suppressed by the intact circadian clock, and in its absence, by exposure to a standard photoperiod. These results support and extend the literature addressing the complex interactions between masking and clock-controlled components of overt circadian rhythms.
Page 103. Tunable Seers Activity-Dependent Development of Vision in Fly and Cat HELMUT VB HIRSCH,... more Page 103. Tunable Seers Activity-Dependent Development of Vision in Fly and Cat HELMUT VB HIRSCH, SUZANNAH BLISS TIEMAN, MARTIN EARTH, AND HELEN GHIRADELLA INTRODUCTION Programs guiding nervous system development must achieve two goals. ...
To test whether visual experience can affect development of visual behavior in the fruitfly, Dros... more To test whether visual experience can affect development of visual behavior in the fruitfly, Drosophila, we measured the visually-guided choice behavior of groups of flies reared in complete darkness, compared with controls reared in a normal light/dark cycle. We used a simple visual preference test, i.e. choice among four different visual targets each consisting of vertical black lines of a particular width on a white background, using a blind testing procedure so that the individual rearing histories were not known by the tester. Both groups of flies were strongly attracted to the vertical lines; however, generally the dark-reared flies were more attracted to the wider stimulus lines than were the control flies. Control experiments in which normally reared adults were kept for several days in darkness showed that the effects of dark-rearing were not simply due to being in darkness, but depended upon the timing of the deprivation. The results indicate that the development of visual behavior can be affected by visual experience in Drosophila and thus open the possibility of using Drosophila for genetic dissection of mechanisms of visual plasticity.
ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical o... more ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical overview of the biology of neuroplasticity. Environmental enrichment, social stimulation, exercise, and pharmacologic interventions (eg, antidepressant drugs) have all been reported to influence neuroplasticity. Since adaptive changes in the brain involve changes in how genes are expressed, we look at some approaches to that. Next, we consider a vital, but often overlooked, factor in brain development throughout life—social interactions. We conclude with a future perspective.
Kittens were reared so that each eye received normal patterned vision on alternate days. If the e... more Kittens were reared so that each eye received normal patterned vision on alternate days. If the eyes received equal periods of stimulation, the visual fields were normal. If one eye received much more experience than the other, the field of the less experienced eye was restricted to the temporal hemifield. This change, which differs from that observed when one or both eyes are deprived continuously of patterned input, suggests that an imbalance in the duration of stimulation can influence the outcome of the normal competitive interaction between pathways from the two eyes and can cause a selective suppression of a portion of the input from the less experienced eye. This suppression may involve the ipsilateral retino-geniculo-cortical pathways or it may involve the entire cortical pathway from the less experienced eye, leaving the colliculus to control responses to visual targets.
Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing ... more Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing radiation on human beings which do not produce any short-term effects, can serve as exemplification of (a) the existing trend of growing political integration of science and ...
We present data on the effects of various concentrations of the organophosphorus insecticide, fen... more We present data on the effects of various concentrations of the organophosphorus insecticide, fenitrothion, on development, reproduction and eggshell structure of Spodoptera exigua. The insecticide did not change the male/female ratio in tested populations. The ...
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