Endogenous Activity Rhythm Research Articles

Evaluation of optic tract section on the locomotor activity rhythm of the shore crab Carcinus maenas

1. 1. Carcinus maenas exhibits a complex endogenous circatidal and circadian locomotor activity rhythm, with peaks of activity associated with the time of local high water. 2. 2. Unilateral optic tract sectioned crabs retain the ability to exhibit a circatidal locomotor rhythm following a cold chill treatment of 4°C for 12hr. Cold shock is known to induce a consistent tidal locomotor rhythm in intact crabs. 3. 3. Bilateral optic tract section of crabs results in the inability to display rhythmic locomotor activity following cold shock. 4. 4. It is proposed that bilateral optic tract section disrupts neural integration linking retinal photoreceptors and the neurosecretory-sinus gland complex in the eyestalk with a presumptive neural clock in the cerebral ganglion. 5. 5. In intact crabs these pathways enable cyclic environmental information to synchronize a regulated release of the neural depressing hormone NDH into the haemolymph, which mediates the overt locomotor activity rhythm. 6. 6. A summary diagram of the proposed neural and hormonal components involved in such regulation is presented.

The rôle of biological rhythms in some sand beach cirolanid Isopoda

It has been suggested that endogenous circa-tidal activity rhythms are used to maintain zonation in some cirolanid isopods, but exogenous factors could equally well maintain observed zonation patterns at mid-tide levels on sand beaches. Examination of the rhythmic behaviour of closely related cirolanids from the low shore and immediate sublittoral demonstrates that endogenous rhythmicity is essential to the maintenance of zonation in these species. During unpredictable events such as storms, however, other behavioural mechanisms are utilized to return isopods to optimal zones.

Entrainment of the circatidal rhythm of the estuarine amphipod Coroph1um volutator (pallas) to non-tidal cycles of inundation and exposure in the laboratory

The endogenous rhythm of swimming activity shown by the estuarine amphipod Corophium volutator (Pallas) has been studied in animals subjected to periodic inundation under controlled laboratory conditions. A rhythm of circatidal frequency which persisted under constant conditions was recorded in animals entrained to cycles of 8-, 12- and 24-h periods, whereas animals entrained to 6-h cycles appeared to follow the entraining regimen directly, although the free running rhythm was less distinct. Cycles of 4-h period failed to induce rhythmicity. The results support the hypothesis that the endogenous oscillator has a circatidal frequency. The period for which the animals are submerged is important with regard to entrainment but the effective parameters of the imposed regimen are incompletely understood in this respect.

The Location of Circa-Tidal Pacemakers in the Estuarine Amphipod Corophium Volutator Using A Selective Chilling Technique

ABSTRACT The anatomical location of the control centre(s) for the endogenous tidal rhythm of swimming activity shown by Corophium volutator (Pallas) has been investigated using a selective chilling technique. Rephasing occurred on chilling the whole animal to −3 °C or on chilling either the supra- or sub-oesophageal ganglion alone, whereas cold pulses applied to the telson or mid-body regions were without effect. Ablating the eyes had no effect on the endogenous rhythm. The results are interpreted in terms of two autonomous control centres.

The effects of salinity changes on the endogenous circa‐tidal rhythm of the amphipodCorophium volutator(Pallas)

The endogenous rhythm of swimming activity shown by Corophium volutator has been studied in sea water of different concentrations, and after subjecting freshly collected animals to pulses of different salinities. The free‐running period of the rhythm shows no significant change in different ambient salinities but a significant correlation exists between the phase of the rhythm and the concentration of the recording medium. These phase shifts are evident in the first activity peak following transfer, lower salinities effecting a phase advance whereas higher salinities bring about a phase delay. The rhythm is not equally susceptible to high salinity pulses at all stages of the tide and a phase response curve has been constructed for 3 h pulses of 40‰ S. Maximum delay follows pulses given around high water while similar pulses applied later in the tidal cycle cause a phase advance. Pulses of increased salinity, given at a tidal frequency are effective in rephasing the activity rhythm but are insufficient to ...

The effects of ethanol, valinomycin and cycloheximide on the endogenous circa‐tidal rhythm of the estuarine amphipodCorophium volutator(Pallas)

The free‐running period of the endogenous rhythm of swimming activity shown by Corophium volutator is unaffected by sea water solutions of ethanol in the 0.001 to 0.05% range but phase delays of up to 130 minutes are observed. The observed phase shift occurs within the first few hours after transfer and the magnitude of the changes is unrelated to the ethanol concentration. The ionophore valinomycin also induces a phase delay, the magnitude of which is inversely proportional to the concentration of the reagent. Phase response curves for ethanol and valinomycin have been calculated following pulsed application of the drugs. Ethanol applied during the early ebb induces a phase delay of about 90 minutes while similar treatment at the time of low water advances the rhythm by 30 minutes. Valinomycin pulses induce phase shifts which are opposite in sign to those produced by ethanol alone. The effects of cyclohexamide are more equivocal, the rhythm persisting in dilute solutions but attenuating rapidly in higher...

Rhythms of locomotion and oxygen consumption in the estuarine amphipod Corophium volutator (Crustacea: Amphipoda).

The estuarine amphipod Corophium volutator exhibits an endogenous circatidal rhythm of swimming activity, with maxima occurring just after the expected time of high water, under constant laboratory conditions. Oxygen uptake by Corophium is also subject to modulation across the tidal cycle. The period of highest oxygen uptake occurs during the ebb tide, in phase with the period of maximum swimming activity. A second increase in oxygen uptake during the early flood tide is thought to reflect either in-burrow activity or a previously described rhythm of emergence. This being so, this aspect of the animal's respiratory metabolism may be regulated by an autonomous oscillator independent of that governing the animal's swimming behaviour.

Oviposition by African malaria vector mosquitoes

Blood-fed females of the Anopheles gambiae species complex, most of which would have been A. gambiae Giles sensu stricto, were collected from a freshwater locality in coastal Kenya and used for laboratory studies of their temporal patterns of oviposition. Contrary to previous reports these patterns were not found to be constrained to the early hours of the night but varied widely, evidently dependent on the time of blood-feeding and on subsequent temperatures but not on endogenous activity rhythms of any circadian nature other than daytime inhibition. After two days at mean temperatures ranging from 26 X 25 to 28.1 degrees C the combined results of ten nights showed a build-up from dusk to a peak in the hour following midnight, falling more steeply towards dawn. In combination with patterns derived from mosquitoes re-fed at 20-21.00 hours and 05-06.00 hours this indicated oviposition with a mean 44-47 hours after blood feeding. Considered in the context of available relevant field evidence, temporal patterns of oviposition by A. gambiae in the field in the warmer lowlands of Africa would be expected to show an initial, more abrupt peak in the early night (contributed mainly by females which had failed to oviposit on the night when first due), followed by a more diffuse peak. Patterns would be dependent on local conditions of blood-feeding, temperature and distance from daytime resting sites.

The effects of low temperature pulses in rephasing the endogenous activity rhythm ofCorophium volutator(Pallas)

The endogenous rhythm of swimming activity shown byCorophiumis reset by pulses of sub-zero temperature, the activity maxima being rephased to the time of rewarming at the end of the cold period. Chilling is not equally effective at all stages of the tide, pulses applied during the flood tide causing a phase delay, while those applied during the ebb advance the rhythm. Chilling at the time of low water induces arrhythmic swimming and it is suggested that the rhythm enters a state of equivocation at this time when an advance and a delay in phase are both equally probable. This results in the loss of synchronization between individuals and the disappearance of the overt rhythm from the sample population.

Variation in the naturally occurring rhythm of the estuarine amphipod,Corophium volutator(Pallas)

The endogenous activity rhythm of the estuarine amphipodCorophium volutatorhas been studied by direct observation and with the use of time lapse photography. The rhythm persists under constant conditions having a free running period of between 12 and 13 h, and with activity maxima occurring during the early ebb. Freshly collected animals show a rhythm which is modulated on a semi-lunar basis, the activity maxima being attenuated during the neap tide periods, and the rhythm has also been found to vary in definition throughout the year. The activity pattern is most clearly denned in early summer and autumn, the population becoming arrhythmic during the winter months. The rhythm is relatively unaffected by the ambient light intensity and temperature of the recording conditions, and is evident in all post-natal stages of development. The possibility of mutual entrainment is discussed.

The endogenous locomotor activity rhythm of four supralittoral peracarid crustace

The ‘strength’ of the endogenous locomotor activity rhythm of four peracarid crustacean species, denned by the precision and persistence of the rhythm, was examined with particular reference to a ‘burrowing’ versus epifaunal supralittoral life-style. The ‘strength’ of the endogenous component of the activity rhythm was also illustrated using a modified periodogram analysis. In all species, the talitrid amphipodsTalitrus saltator, Talorchestia deshayesi, Orchestra gammarellaand the oniscoid isopodLigia oceanica, the laboratory-monitored rhythm and the field emergence pattern displayed a nocturnal, circadian pattern with no clear evidence of any circa-tidal influence. The precision and particularly the persistence of the rhythm of the sand-shore burrowing speciesT. saltatorandT. deshayesiare especially well developed, although a ‘strong’ endogenous component is present in the rhythm of all four species. The significance of the endogenous locomotor rhythms is considered with respect to the supralittoral ecology of the species.

Observations on the tidal activity rhythm of the periwinkleLittorina nigrolineata(Gray)

The spontaneous activity pattern of the periwinkle L. nigrolineata has been studied by direct observation in the field and under controlled conditions in the laboratory. In the laboratory the animals are induced to crawl by both immersion and exposure under simulated tidal conditions, and the increased activity following emersion has been confirmed by field observations. Animals kept submerged under constant conditions show an endogenous activity rhythm with a free running period of about 12 to 13 hours. The main activity periods occur about 2 hours after the onset of inundation and the rhythm rephases almost immediately to the time of immersion. There is also evidence for a further endogenous component with peaks corresponding to the time of subjective emersion. The rhythm is modulated on a circadian basis, and is less pronounced during the neap tide period, and during the winter months.

DIEL ACTIVITY PATTERN IN LARVAE OF THE AUSTRALIAN CADDISFLY HELICOPSYCHE MURRUMBA MOSELY (TRICHOPTERA: HELICOPSYCHIDAE)

AbstractThe diel activity patterns of Helicopsyche murrumba (Trichoptera) were observed over two 24 h periods in the laboratory with either normal or reversed lighting regimes. During normal conditions, activity reached a peak 3 h after sunrise (S.R. 0600 h) and remained active until 2 h before sunset (S.S. 1800 h) With stepwise reduction of illumination from > 250 lux to < 0.2 lux over an artificial 2 h “sunset” period the larvae moved back onto rocks and the level of activity gradually declined. No apparent stimulus to move under rocks was observed. Under reversed lighting conditions the periods of high and low activity were also reversed. It is suggested that an endogenous rhythm of activity is absent in H. murrumba and that diel activity is controlled by a direct response to light intensity, an exogenous component.

Circadian rhythm of swimming activity in juvenile pink salmon (Oncorhynchus gorbuscha)

The circadian rhythm of swimming activity and the role of the daily illumination cycle in the synchronization of this rhythm were studied in individual juvenile pink salmon. Sixty eight percent of all fish examined (n=38) were day-active when exposed to a 12 h L:12 h D cycle; the remaining fish were nocturnally active. One half of the fish tested under laboratory conditions of continuous, constant light intensity (LL) and constant temperature showed unambiguously endogenous activity rhythms with circadian periods for up to 10 d. The remaining fish were arrhythmic. Mean period length of the free-running activity rhythms for diurnal fish in LL shortened with constant light intensity increasing from 6 to 600 lx, as predicted by the circadian rule. In contrast, mean free-running period for nocturnal fish did not vary significantly with similarly increasing constant light intensity. Mean swimming speed (activity level) of both diurnal and nocturnal fish increased significantly with increasing light intensity. This is suggestive of a positive photokinetic response. When subjected to a phase-delayed LD cycle, the fish resynchronized their daily rhythms of activity with this new LD cycle after only one transient cycle in most instances. Hence, the timing of the daily activity rhythms appeared to occur through the direct masking action of the illumination cycle on activity, rather than through entrainment of an endogenous circadian system.

The entraining effect of turbulence on the circa-tidal activity rhythm and its semi-lunar modulation in Eurydice pulchra

Turbulence measurements taken at the water's edge at Derbyhaven beach, Isle of Man, indicated that maximum turbulence on any particular tide predictably occurred at the time of high water. However, long term monitoring failed to record any predictable semi-lunar modulation of the intensity of turbulence. Laboratory experiments showed that cycles of mechanical agitation applied for 2 h every 12 h for 4 days could entrain the endogenous circa-tidal activity rhythm of adult Eurydice pulchra. The effect was the same with shaking in constant light or constant darkness. However, when applied at different phases of an imposed L/D cycle, the synchronizer had a varying effect. The strongest entrainment occurred when shaking was phased to ‘midday’ and ‘midnight’ - a phase relationship paralleled by the high water of spring tides. Minimal synchronizer effect occurred when shaking was applied at ‘dawn’ and ‘evening’, the phase relationship of neap tide high water to the solar day. The varying response is suggested to be the origin of the semi-lunar modulation of activity seen in Eurydice pulchra.

Daily patterns of locomotor activity in a wandering spider

ABSTRACT. Cupiennius salei Keys., a lycosid spider, is night‐active in its natural habitat in the highlands of Guatemala. Locomotor activity begins at dusk after several transitional states, each of which is correlated with a particular light level. Actograph measurements in controlled conditions (LD 12:12 or reversed cycles) show that the spiders begin walking immediately after dark. The activity maximum is reached within the first 3 h of the scotophase (though some spiders displayed additional lights‐on activity in the first hour of the photophase). In DD, Cupiennius shows an endogenous activity rhythm with a mean period of 24.9 h (± 0.31, SE); typically during the first four to six cycles in DD the rhythm ‘splits’ into two components running at different frequencies. In LL (26 1x) the walking activity became arrhythmic. The results are discussed with reference to field and laboratory observations of Cupiennius behaviour and to the consequences for future physiological research with this species.

The effect of dusk and dawn on the locomotor activity rhythm of Talitrus saltator (Montagu) (Crustacea: Amphipoda)

Entrainment of the nocturnal, endogenous locomotor activity rhythm of Talitrus saltator (Montagu) by the natural light-dark cycle is non-parametric, the phase of the rhythm shifting only in response to changes in the time of an experimentally simulated ‘dawn’ transition. The difference in response to light at ‘dusk’ and ‘dawn’ illustrates a phase-dependent responsiveness common to endogenous rhythms. Activity begins after complete darkness, with cessation always occurring during the ‘dawn’ transition and never continuing past the onset of total experimental illumination. The point of activity cessation is taken to be the position of a synchronizing cue controlling entrainment. The ‘dawn’ cue appears to be an absolute irradiance level of approximately 1.5 × 10 −4 W/m 2 (1.5 lux). The implications of such a cue are discussed in relation to field behaviour.

Water loss and locomotory activity in Agama persica and Diplometopon zarudnyi from Kuwait

Evaporative water loss in dry, still, air was measured from both species, and found to be surprisingly low in Diplometopon zarudnyi —despite its subterranean mode of life. The eggs of Agama persica, however, rapidly lost and absorbed water. A. persica is day-active and showed a marked endogenous rhythm which could easily be synchronized by reversed lighting. In contrast, D. zarudnyi showed no periodicity even in alternating light and darkness. Although more active at higher temperatures D. zarudnyi is unusual in that it does not possess an endogenous circadian activity rhythm.

The adaptation of digestive enzymes to temperature, season and diet in roach, Rutilus rutilus L. and rudd Scardinius erythrophthalmus L. 1. Amylase

Seasonal changes of the amylolytic activity in the gut content of roach and rudd in four Tyrolean lakes and the adaptation of the amylase to four acclimation temperatures and to different natural foods were studied. In roach amylolytic activity varied with the environmental temperature. Between September and October, however, enzyme activity shifted to a higher level where it remained for the entire cold season. In rudd, which has almost the same seasonal pattern of amylolytic activity as the roach, the activity of the enzyme is independent of environmental temperature. This suggests an endogenous rhythm of enzyme activity. Under natural conditions the roach, but not the rudd, has a higher amylolytic activity when feeding on animals and a lower activity when feeding on detritus. The laboratory experiments revealed no significant differences in amylase activity between fish feeding on animals and those feeding on plants, although in both species the enzymatic activity was lowest when Chara served as food.

Dawn signal as a rhythmical timer for the seasonal adaptive variation of CAM: a model

Abstract Photoperiodism, known to control the level of CAM in different types of CAM plants (e.g. Kalanchoe blossfeldiana, Bryophyllum daigremontianum), would act as a reliable timer for seasonal coherent adaptation. Two different endogenous rhythms (malic enzyme activity, PEP carboxylase capacity) appear to be separately coupled to dawn and dusk, respectively, thus achieving time‐compartmentation of CAM; this feature suggests involvement of an ‘internal coincidence’ type of clock mechanism.Persistence in continuous darkness of the rhythm of malic enzyme activity (measured by label incorporation into pyruvate or by CO2 output) establishes its endogenous character and shows that light is not necessary for malate decarboxylation. The role of the dawn signal would be to entrain the CAM system, i.e. to phase the endogenous rhythm of malic enzyme activity correctly to local time. The possibility of an effect of the phase of the PEP carboxylase rhythm on the phase of the decarboxylation rhythm is ruled out by the presence of the intermediary malate storage step. Phase responses to red and to far‐red show that phytochrome is involved in rephasing the rhythm of malic enzyme activity.The relative position of dusk affords a ‘measurement’ of the season by the CAM system entrained by dawn. According to the dusk‐dawn interval, the level of PEP carboxylase capacity (amount of active enzyme) is modified, resulting in changes of CAM level (high activity under short days).