Long photoperiod impairs learning in male but not female medaka

Tubers of yellow nut sedge (Cyperus esculentus L.) were collected from four farm fields representing three soil types in southern Ontario in November of 1974 or 1975. These fields contained from 760 to 8,484 tubers/m2 in the top 40 cm of soil. Tubers extracted from these soils failed to sprout following 6 wk of storage under dry conditions, but sprouting approached 100% if previously stored under cool, moist conditions. Cool temperatures during dry storage for 90 wk reduced subsequent sprouting. Tubers sprouted as well in the greenhouse as in petri plates in a germination chamber. Root growth averaged 2 cm/day in glass-lined root boxes and tuber initiation commenced 90 days after planting. Tuber production was greatest under a short day length of 12 h or less, while shoot and root growth was stimulated by a long photoperiod.

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Long photoperiod in winter is more effective than food deprivation in stopping unwanted sexual maturation in Arctic charr

Aquaculture ◽

10.1016/j.aquaculture.2018.11.007 ◽

2019 ◽

Vol 501 ◽

pp. 213-218 ◽

Cited By ~ 2

Author(s):

Q. Liu ◽

J. Duston

Keyword(s):

Food Deprivation ◽

Sexual Maturation ◽

Arctic Charr ◽

Long Photoperiod

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Age-related and photoperiodic variation of the DAZ gene family in the testis of the Syrian hamster (Mesocricetus auratus)

Zygote ◽

10.1017/s0967199418000023 ◽

2018 ◽

Vol 26 (2) ◽

pp. 127-134 ◽

Cited By ~ 1

Author(s):

Candela Rocío González ◽

Luciana Moverer ◽

Ricardo Saúl Calandra ◽

Silvia Inés González-Calvar ◽

Alfredo Daniel Vitullo

Keyword(s):

Protein Expression ◽

Gene Family ◽

Syrian Hamster ◽

Mesocricetus Auratus ◽

Cell Number ◽

The Novel ◽

Age Related ◽

Mrna And Protein Expression ◽

Long Photoperiod ◽

Daz Gene

SummaryThe Deleted in AZoospermia (DAZ) gene family regulates the development, maturation and maintenance of germ cells and spermatogenesis in mammals. The DAZ family consists of two autosomal genes, Boule and Dazl (Daz-like), and the Daz gene on chromosome Y. The aim of this study was to analyze the localization of DAZL and BOULE during testicular ontogeny of the seasonal-breeding Syrian hamster, Mesocricetus auratus. We also evaluated the testicular expression of DAZ family genes under short- or long-photoperiod conditions. In the pre-pubertal and adult testis, DAZL protein was found mainly in spermatogonia. BOULE was found in the spermatogonia from 20 days of age and during the pre-pubertal and adult period it was also detected in spermatocytes and round spermatids. DAZL and BOULE expression in spermatogonia was strictly nuclear only in 20-day-old hamsters. We also detected the novel mRNA and protein expression of BOULE in Leydig cells. In adult hamsters, Dazl expression was increased in regressed testis compared with non-regressed testis and DAZL protein expression was restricted to primary spermatocytes in regressed testis. These results show that DAZL and BOULE are expressed in spermatogonia at early stages in the Syrian hamster, then both proteins translocate to the cytoplasm when meiosis starts. In the adult regressed testis, the absence of DAZL in spermatogonia might be related to the decrease in germ cell number, suggesting that DAZ gene family expression is involved in changes in seminiferous epithelium during photoregression.

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Influence of photoperiod and gonadal status on food intake, adiposity, and gene expression of hypothalamic appetite regulators in a seasonal mammal

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00417.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. R242-R252 ◽

Cited By ~ 19

Author(s):

Chantacha Anukulkitch ◽

Alexandra Rao ◽

Frank R. Dunshea ◽

Dominique Blache ◽

Gerald A. Lincoln ◽

...

Keyword(s):

Gene Expression ◽

Food Intake ◽

Arcuate Nucleus ◽

Leptin Receptor ◽

Reproductive Axis ◽

Pomc Gene ◽

Gonadal Status ◽

Long Photoperiod ◽

Refractory Phase

We studied the effects of photoperiod on metabolic profiles, adiposity, and gene expression of hypothalamic appetite-regulating peptides in gonad-intact and castrated Soay rams. Groups of five to six animals were studied 6, 18, or 30 wk after switching from long photoperiod (LP: 16 h of light) to short photoperiod (SP: 8 h of light). Reproductive and metabolic indexes were measured in blood plasma. Expression of neuropeptide Y (NPY), proopiomelanocortin (POMC), and leptin receptor (ObRb) in the arcuate nucleus was measured using in situ hybridization. Testosterone levels of intact animals were low under LP, increased to a peak at 16 wk under SP, and then declined. Voluntary food intake (VFI) was high under LP in both intact and castrated animals, decreased to a nadir at 12–16 wk under SP, and then recovered, but only in intact rams as the reproductive axis became photorefractory to SP. NPY gene expression varied positively and POMC expression varied negatively with the cycle in VFI, with differences between intact and castrate rams in the refractory phase. ObRb expression decreased under SP, unrelated to changes in VFI. Visceral fat weight also varied between the intact and castrated animals across the cycle. We conclude that 1) photoperiodic changes in VFI reflect changes in NPY and POMC gene expression, 2) changes in ObRb gene expression are not necessarily determinants of changes in VFI, 3) gonadal status affects the pattern of VFI that changes with photoperiod, and 4) in the absence of gonadal factors, animals can eat less but gain adiposity.

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Probability of pregnancy before ninety days postpartum in water buffaloes

Archivos Latinoamericanos de Producción Animal ◽

10.53588/alpa.300104 ◽

2021 ◽

Vol 30 (1) ◽

pp. 29-34

Author(s):

Hector Nava-Trujillo ◽

Robert Valeris-Chacin ◽

Adriana Morgado-Osorio ◽

Javier Hernández ◽

Janeth Caamaño ◽

...

Keyword(s):

Mixed Model ◽

Linear Mixed Model ◽

Water Buffalo ◽

Mixed Effects ◽

Short Photoperiod ◽

Water Buffaloes ◽

Negative Effect ◽

Log Odds ◽

First 90 Days ◽

Long Photoperiod

This study aimed to determine the effect of parity and season of calving on the probability of water buffalo cows becoming pregnant before 90 days postpartum. A retrospective analysis of reproductive records of 1,465 water buffaloes with 3,181 pregnancies was carried out. Buffaloes were grouped according to parity in one, two, or three and more calvings. Season of calving was created with the following values: long photoperiod (March-August) and short photoperiod (September-February) and predicted probabilities from the mixed-effects logistic regression model were calculated, and a generalized linear mixed model was fitted with random intercepts to calculate the log odds of becoming pregnant ≤90 days postpartum. The probability of pregnancy ≤90 days postpartum was 0.3645, and this was lower in primiparous (0.2717) in comparison with two-calved (0.3863) and three or more calving buffaloes (0.5166). Probability of pregnancy ≤90 days postpartum increased 1.77 odds by each increase in parity. The probability of becoming pregnant ≤90 days postpartum was higher in water buffaloes calving during the short photoperiod season (0.4239 vs. 0.2474, P>0.000), and water buffaloes calving during the long photoperiod season only had 0.2645 odds to become pregnant than those calving during the short photoperiod season. The negative effect of long photoperiod was observed indifferently of parity. In conclusion, primiparity and the long photoperiod affect water buffalo cow's reproductive performance, decreasing pregnancy probability during the first 90 days postpartum.

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Photoperiodic Control of Diapause Induction in the Larva of Lucilia Caesar L. (Diptera: Calliphoridae)

Journal of Experimental Biology ◽

10.1242/jeb.46.1.117 ◽

1967 ◽

Vol 46 (1) ◽

pp. 117-122

Author(s):

R. A. RING

Keyword(s):

Direct Effect ◽

Diapause Induction ◽

Short Photoperiod ◽

Photoperiodic Control ◽

One Stage ◽

Photoperiod Regime ◽

Absolute Length ◽

The Absolute ◽

Diapause Incidence ◽

Long Photoperiod

1. It has been shown that photoperiod has a direct effect on the larva of Lucilia casear L. in the induction of diapause. 2. Transference of larvae from long to short photoperiod conditions during the 1st, 2nd, or 3rd instar increases their tendency to enter diapause. Conversely, transfer from short to long photoperiod conditions decreases their tendency to enter diapause. 3. Larvae are sensitive to changes in the absolute length of the photoperiod during all instars. The reaction is not restricted to any one stage but tends to be cumulative; thus the earlier the larvae are transferred from one photoperiod regime to another then the greater the contrast in diapause incidence between experimental groups and controls.

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Pre- and postnatal effects of photoperiod on collared lemmings (Dicrostonyx groenlandicus)

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1994.267.4.r879 ◽

1994 ◽

Vol 267 (4) ◽

pp. R879-R887 ◽

Cited By ~ 1

Author(s):

B. A. Gower ◽

T. R. Nagy ◽

M. H. Stetson

Keyword(s):

Subsequent Development ◽

Serum Prolactin ◽

Hair Length ◽

Dark Cycle ◽

Guard Hair ◽

Short Day ◽

Dicrostonyx Groenlandicus ◽

Offspring Growth ◽

Pelage Color ◽

Long Photoperiod

We investigated the hypothesis that photoperiod information received during the prenatal and/or early postnatal periods influences subsequent development in collared lemmings. Pregnant lemmings were exposed to either a short [8:16-h light-dark cycle (8:16)] or long (22:2) photoperiod throughout gestation. On the day of birth, pups were cross-fostered to dams housed in either short or long photoperiod. After an 11-day experimental lactational period (LACT), all animals were transferred to an intermediate photoperiod (16:8), the response to which depends on prior photoperiod exposure. Pups remained on this photoperiod until death at postnatal day 90. Information received during gestation (GEST) influenced offspring growth, pelage color, guard hair length, presence of the bifid claw at weaning, testes mass at 10 wk postweaning, and serum prolactin (PRL). Parameters measured at weaning reflected directly the photoperiod experienced during GEST (e.g., short-day GEST pups had white pelage). Conversely, parameters measured at 10 wk postweaning reflected the change in photoperiod experienced between GEST and 16:8 (e.g., short-day GEST young had gray pelage, indicative of an increase in photoperiod). Information received during LACT influenced growth and the presence of the bifid claw at weaning.

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CIRCA-ANNUAL RHYTHMS OF PROLACTIN SECRETION IN EWES AND THE EFFECT OF PINEALECTOMY

Journal of Endocrinology ◽

10.1677/joe.0.0840083 ◽

1980 ◽

Vol 84 (1) ◽

pp. 83-89 ◽

Cited By ~ 14

Author(s):

C. J. MUNRO ◽

K. P. McNATTY ◽

L. RENSHAW

Keyword(s):

Plasma Concentration ◽

Pineal Gland ◽

Seasonal Variations ◽

Reproductive Tract ◽

Plasma Concentrations ◽

Prolactin Secretion ◽

Transitional Period ◽

Short Photoperiod ◽

Winter Period ◽

Long Photoperiod

Changes in the plasma concentration of prolactin in intact, pinealectomized, shampinealectomized, ovariectomized and hysterectomized ewes were investigated over a period of 11 months. The concentrations of prolactin were consistently low (<20 ng/ml) during the winter months (short photoperiod) in the intact, sham-pinealectomized, ovariectomized and hysterectomized animals. In contrast, the concentrations of prolactin were consistently raised (> 50 ng/ml) during the summer months (long photoperiod) in the same groups. During the transitional period from winter to summer the concentrations of prolactin were correlated with the reproductive status of the animals. In the pregnant animals, the prolactin concentrations increased from low values during pregnancy to high values at parturition. During lactation, the concentrations of prolactin in these animals remained high, although they were lower than those found subsequently during the summer months when the ewes were no longer lactating. In the non-pregnant ewes (i.e. the ovariectomized and hysterectomized animals), the prolactin concentrations increased more gradually during the transitional period from winter to summer than was the case in the parturient animals. In the pinealectomized ewes, the plasma concentrations of prolactin were raised throughout the year, irrespective of whether the animals were pregnant, lactating or in anoestrus. In these animals, the only occasion when prolactin concentrations were consistently low was during the mid-winter period, although they were also low at times during the period of oestrous activity. It was concluded that the circa-annual pattern of prolactin concentrations in ewes is primarily determined by the photoperiod, and that the pineal gland in the ewe is an important translator of the photoperiod. Parturition and suckling have important, but secondary, influences. Moreover, it was concluded that the secretions from the reproductive tract and the seasonal variations in temperature normally have little influence by themselves on the circa-annual rhythm of prolactin.

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Photoperiod alters phase difference between activity onset in vivo and mPer2::luc peak in vitro

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90510.2008 ◽

2008 ◽

Vol 295 (5) ◽

pp. R1688-R1694 ◽

Cited By ~ 8

Author(s):

Carl T. Mickman ◽

Jeremy S. Stubblefield ◽

Mary E. Harrington ◽

Dwight E. Nelson

Keyword(s):

Phase Relationship ◽

Stable Phase ◽

Light Cycle ◽

Behavioral Rhythms ◽

Activity Onset ◽

Long Photoperiod ◽

Initial Cycle ◽

Phase Relationships

Photoperiod is a significant modulator of behavior and physiology for many organisms. In rodents changes in photoperiod are associated with changes in circadian period and photic resetting of circadian pacemakers. Utilizing rhythms of in vivo behavior and in vitro mPer2::luc expression, we investigated whether different entrainment photoperiods [light:dark (L:D) 16:8 and L:D 8:16] alter the period or phase relationships between these rhythms and the entraining light cycle in Per2::luc C57BL/6J mice. We also tested whether mPer2::luc rhythms differs in anterior and posterior suprachiasmatic nucleus (SCN) slices. Our results demonstrate that photoperiod significantly changes the timing of the mPer2::luc peak relative to the time of light offset and the activity onset in vivo. In both L:D 8:16 and L:D 16:8 the mPer2::luc peak maintained a more stable phase relationship to activity offset, while altering the phase relationship to activity onset. After the initial cycle in culture, the period, phase, and peaks per cycle were not significantly different for anterior vs. posterior SCN slices taken from animals within one photoperiod. After short-photoperiod treatment, anterior SCN slices showed increased-amplitude Per2::luc waveforms and posterior SCN slices showed shorter-duration peak width. Finally, the SCN tissue in vitro did not demonstrate differences in period attributable to photoperiod pretreatment, indicating that period aftereffects observed in behavioral rhythms after long- and short-day photoperiods are not sustained in Per2::luc rhythms in vitro. The change in phase relationship to activity onset suggests that Per2::luc rhythms in the SCN may track activity offset rather than activity onset. The reduced amplitude rhythms following long-photoperiod treatment may represent a loss of coupling of component oscillators.

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Physiological maturation and reproductive behaviour of female doves (Streptopelia risoria) held under long and short photoperiods

Canadian Journal of Zoology ◽

10.1139/z76-038 ◽

1976 ◽

Vol 54 (3) ◽

pp. 343-354 ◽

Cited By ~ 5

Author(s):

N. R. Liley

Keyword(s):

Nest Site ◽

Reproductive Behaviour ◽

Egg Laying ◽

Nest Building ◽

Short Photoperiod ◽

Courtship Behaviour ◽

Male And Female ◽

Streptopelia Risoria ◽

Long Photoperiod

Female doves were held under long (16 h per day), or short (8 h per day) photoperiod and exposed to actively courting males for 4.5 h per day for 15 days. The occurrence of egg laying and nest building was recorded daily. Behavioural observations were recorded for 15 min on alternate days.Seven out of eight long-photoperiod females laid eggs, whereas only one of nine short-photoperiod females began egg laying. Soliciting by the female and nest building involving male and female are the best indicators of a female's readiness to begin breeding. The occurrence of these activities is correlated with the growth of follicles and oviduct. Copulation and associated behaviours are not correlated with follicle and oviduct growth, and appear to be controlled by factors different from those governing courtship behaviour associated with the nest site.

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