Reproductive response to photoperiod affects corticosterone and immunoglobulin G concentrations in prairie voles (Microtus ochrogaster)

1996 ◽  
Vol 74 (3) ◽  
pp. 576-581 ◽  
Author(s):  
Randy J. Nelson ◽  
Benjamin Asfaw ◽  
A. Courtney DeVries ◽  
Gregory E. Demas
Keyword(s):  
Immunoglobulin G ◽  
Survival Rates ◽  
Reproductive Organ ◽  
Microtus Ochrogaster ◽  
Day Length ◽  
Seasonal Fluctuations ◽  
Prairie Voles ◽  
Serum Corticosterone ◽  
Long Day ◽  
Short Days

Nontropical rodent species display prominent breeding seasons mediated by photoperiod. Nonreproductive functions also exhibit seasonal changes; for example, fluctuations in adrenal activities may affect immune function and, ultimately, drive seasonal fluctuations in survival rates. The effects of photoperiod on adrenal and splenic masses and serum concentrations of corticosterone and immunoglobulin G (IgG) were evaluated in male prairie voles (Microtus ochrogaster). In one experiment, photoperiodic effects on adrenal and splenic masses and serum corticosterone and IgG levels were assessed in males that maintained "summer-like" reproductive systems after 8 weeks of short-day exposure. In a second experiment, the same parameters were examined in males in which testicular regression occurred after 8 weeks on short days. Voles that maintained reproductive organ size on short days failed to display other photoperiod-mediated differences in body, splenic, or adrenal masses or in serum corticosterone or IgG concentrations. In contrast, voles that underwent reproductive regression in response to short days decreased absolute adrenal mass and body mass compared with long-day animals, and also increased serum corticosterone concentrations and decreased IgG levels compared with their long-day counterparts. Taken together, these data indicate that reproductive responsiveness to day length may be linked to seasonal fluctuations in nonreproductive adaptations.

Environmental control of reproduction in Themeda australis

1969 ◽  
Vol 17 (3) ◽  
pp. 375 ◽  
Author(s):  
LT Evans ◽  
RB Knox
Keyword(s):  
Environmental Control ◽  
New Guinea ◽  
Reproductive Behaviour ◽  
Northern Territory ◽  
The Other ◽  
Day Length ◽  
Long Day ◽  
Flowering Behaviour ◽  
Ecological Races ◽  
Short Days

Seedlings and older plants of 30 ecological races of Themeda australis were grown under controlled conditions to determine the effect of day length and vernalization on their flowering and on the incidence of apomixis. The races ranged in origin from latitude 6°S. in New Guinea to latitude 43°S, in Tasmania. One race from New Guinea and several from the Northern Territory behaved as strict short-day plants. The more southerly races, on the other hand, and several from north Queensland were long-day plants. In some, long days were required for both initiation and development of the inflorescence, in others apparently only for initiation. Some races required long days as seedlings, but not as older plants. Races from drier inland areas tended to be indifferent to day length in their flowering behaviour. At least four races from the colder areas responded to vernalization. Both the sexual and the aposporous reproductive pathways are described. Two races were wholly sexual in their breeding system and two appeared to be almost entirely aposporous, but most were versatile, displaying both sexual and aposporous reproductive behaviour. In seven races there was some evidence that day length influenced the reproductive pathway, short days causing increased apospory in all cases, regardless of the day length requirements for flowering.

scholarly journals PHOTOPERIODIC CONTROL OF DEVELOPMENTAL GROWTH IN BEGONIA × TUBERHYBRIDA

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1144G-1144
Author(s):  
Meriam G. Karlsson ◽  
Jeffrey W. Werner
Keyword(s):  
Early Development ◽  
Plant Development ◽  
Root Development ◽  
Growth And Development ◽  
Average Rate ◽  
Day Length ◽  
Seedling Height ◽  
Long Day ◽  
Developmental Growth ◽  
Short Days

Plants of Begonia x tuberhybrida `NonStop Orange', `Clips Orange' and `Musical Orange' were exposed to 1, 2, 3 or 4 weeks of short days initiated at 4 stages of plant development (immediately upon germination, 5 weeks after germination, 10 weeks after germination and 15 weeks after germination). Prior to and succeeding short days, plants were exposed to a day length of 16 hours at 100 μmol·m-2s-1. Short days were 9 hours at an irradiance level of 180 μmol·m-2s-1 to give the same total daily irradiance (5.8 mol· m-2day-1) as long day conditions. The temperature was maintained at 21° ± 4°C during the day and 18° ± 2°C during night. The observed growth and development responses were similar among the studied cultivars. During the period of 4 to 8 weeks after germination, the seedling height increased at an average rate of 0.7 mm day-1 for plants grown under long days and 0.3 mm day-1 for short day plants. The photoperiodic conditions did not affect the number of emerging leaves. The root development was more proliferate on plants allowed to develop under long days compared to plants exposed to short days during early development.

scholarly journals TEMPERATURE DURING EARLY DEVELOPMENT AFFECTS PLANT MORPHOLOGY OF BEGONIA × HIEMALIS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1086f-1086
Author(s):  
M. G. Karlsson ◽  
J. W. Werner ◽  
H.C.H. McIntyre
Keyword(s):  
Early Development ◽  
Plant Morphology ◽  
Dry Weight ◽  
Day Length ◽  
Effect Of Temperature ◽  
Flower Number ◽  
Main Shoot ◽  
Long Day ◽  
The Mean ◽  
Short Days

The effect of temperature during the initial long day period on morphology and plant dry weight was determined for Begonia × hiemalis `Hilda'. Multistem cuttings were planted in 10 cm pots and grown at 13°, 16°, 19°, 22°, 25° or 28°C. The day length was 16 hours at an irradiance level of 280 ± 20 μmol·m-2s-1. After 21 days, the plants were moved to a greenhouse maintained at 20° ± 2°C and short days of 10 hours at 125 ± 20 μmol·m-2s-1. The plants were grown under short days for 14 days and then moved to a day length of 16 hours. At data collection 21 days later (56 days from planting), plant height averaged 185 mm for plants initially grown at 13°, 16°, 19° or 22°C while pants originally grown at 25° and 28°C were 40 and 78 mm shorter than plants started at lower temperatures. The mean number of shoots was 4 on plants exposed to 16°, 19°, 22° or 25°C during early development and decrease to 3 shoots for plants grown initially at 13° or 28°C. The average flower number on the main shoot was similar for plants first exposed to low and intermediate temperatures but decreased rapidly to 0 for plants with early exposure to 28°C. Plants in treatments with early temperatures of 19° or 22°C had the largest above ground dry weight at an average 460 mg.

Latitude affects photoperiod-induced changes in immune response in meadow voles (Microtus pennsylvanicus)

2005 ◽  
Vol 83 (10) ◽  
pp. 1271-1278 ◽  
Author(s):  
L M Pyter ◽  
Z M Weil ◽  
R J Nelson
Keyword(s):  
Immune Responses ◽  
Microtus Pennsylvanicus ◽  
Day Length ◽  
Delayed Type Hypersensitivity ◽  
Deer Mice ◽  
Meadow Voles ◽  
Short Day ◽  
Long Day ◽  
Induced Changes ◽  
Short Days

Animals use day length (photoperiod) to time seasonal adaptations to annual changes in their environment. Reproductive adjustments in deer mice (Peromyscus maniculatus (Wagner, 1845)) from high latitudes are more extensive in response to short days than in deer mice from low latitudes. These adjustments may permit individuals to survive the severe seasonal changes (e.g., temperature and food abundance) in high-latitude environments. Immune function is also affected by photoperiod. Short days were predicted to result in elevated immune and reproductive responses in meadow voles (Microtus pennsylvanicus (Ord, 1815)) from the Northwest Territories (NWT), Canada (~62°N), compared with voles from Ohio (OH), USA (~39°N). Male voles from both latitudes were maintained in long or short days for 10 weeks prior to a delayed-type hypersensitivity (DTH) immune challenge. Both populations displayed similar testicular regression and reduction of testosterone concentrations in short days. DTH immune responses, however, diverged between the two populations. DTH immune responses were enhanced in long-day NWT voles and short-day OH voles, but decreased in short-day NWT voles and long-day OH voles. Total and free corticosterone concentrations did not explain the latitudinal differences in immune responses. These results suggest that photoperiod affects reproductive and immune systems differently and that immune responses may reflect other environmental factors.

Gonadal hormone-dependent and -independent regulation of immune function by photoperiod in Siberian hamsters

2008 ◽  
Vol 294 (2) ◽  
pp. R384-R392 ◽  
Author(s):  
Brian J. Prendergast ◽  
Scott R. Baillie ◽  
Firdaus S. Dhabhar
Keyword(s):  
Immune Function ◽  
Gonadal Hormones ◽  
Day Length ◽  
Gonadal Hormone ◽  
Testosterone Secretion ◽  
Siberian Hamsters ◽  
Long Day ◽  
Sickness Behaviors ◽  
Immunological Effects ◽  
Short Days

Siberian hamsters ( Phodopus sungorus) exhibit changes in reproductive and immune function in response to seasonal variations in day length. Exposure to short days induces gonadal regression and inhibits testosterone secretion. In parallel, short days enhance immune function: increasing leukocyte numbers and attenuating cytokine and behavioral responses to infection. We examined whether photoperiodic changes in leukocyte phenotypes and sickness behaviors are dependent on concurrent photoperiodic changes in gonadal function. Male hamsters were gonadectomized or sham-gonadectomized and either exposed to short days (9 h light/day; SD) or kept in their natal long-day (15 h light/day; LD) photoperiod for 10–13 wk. Blood samples were obtained for leukocyte enumeration, and hamsters were challenged with bacterial LPS, which induced behavioral (anorexia, reductions in nest building) and somatic (weight loss) sickness responses. Among gonad-intact hamsters, exposure to SD increased total and CD62L+ lymphocytes and CD3+ T lymphocytes in blood and significantly attenuated LPS-induced sickness responses. Independent of photoperiod, castration alone increased total and CD62L+ lymphocyte and CD3+ T lymphocyte numbers and attenuated somatic and anorexic sickness responses. Among castrated hamsters, SD exposure increased lymphocyte numbers and suppressed sickness behaviors. In castrated hamsters, the magnitude of most immunological effects of SD were diminished relative to those evident in gonad-intact hamsters. The SD phenotype in several measures of immunity can be instated via elimination of gonadal hormones alone; however, photoperiodic effects on immune function persist even in castrated hamsters. Thus, photoperiod affects the immune system and neural-immune interactions underlying sickness behaviors via gonadal hormone-dependent and -independent mechanisms.

Gonadal and photoperiodic influences on body mass regulation in adult male and female prairie voles

1996 ◽  
Vol 270 (5) ◽  
pp. R1013-R1018 ◽  
Author(s):  
L. J. Kriegsfeld ◽  
R. J. Nelson
Keyword(s):  
Body Mass ◽  
Mass Gain ◽  
The Body ◽  
Prairie Voles ◽  
Male And Female ◽  
Short Day ◽  
Body Mass Regulation ◽  
Long Day ◽  
Survival And Reproduction ◽  
Short Days

Nontropical animals commonly use the annual change in photoperiod to phase seasonal adjustments that promote survival and reproduction. To cope with the energetic requirements of winter, many rodents alter body mass in anticipation of winter. Photoperiodic adjustments are often mediated by the pineal hormone melatonin; melatonin can exert a primary effect on body mass or secondarily affect body mass by changing blood gonadal steroid levels. The present study sought to determine if prairie voles (Microtus ochrogaster) alter body mass in response to short photoperiods. The role of the gonads in body mass regulation was also assessed. In experiment 1, males housed in short days increased body mass at a greater rate than long-day animals. Gonadectomy enhanced the body mass gain in short-day voles. These data suggest that the gonads contribute to short photoperiod-induced changes in body mass in male voles. In experiment 2, females housed in short days increased body mass at a greater rate than long-day animals, regardless of whether the animals were ovariectomized. Ovariectomy did not affect body mass in either long- or short-day animals, suggesting that the ovaries do not contribute to photoperiod-mediated changes in body mass in female prairie voles. Taken together, these studies suggest that male and female prairie voles use photoperiodic information to time seasonal changes in body mass.

scholarly journals PHOTOPERIODIC CONTROL OF DEVELOPMENTAL GROWTH IN BEGONIA × TUBERHYBRIDA

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1144g-1144
Author(s):  
Meriam G. Karlsson ◽  
Jeffrey W. Werner
Keyword(s):  
Early Development ◽  
Plant Development ◽  
Root Development ◽  
Growth And Development ◽  
Average Rate ◽  
Day Length ◽  
Seedling Height ◽  
Long Day ◽  
Developmental Growth ◽  
Short Days

Plants of Begonia x tuberhybrida `NonStop Orange', `Clips Orange' and `Musical Orange' were exposed to 1, 2, 3 or 4 weeks of short days initiated at 4 stages of plant development (immediately upon germination, 5 weeks after germination, 10 weeks after germination and 15 weeks after germination). Prior to and succeeding short days, plants were exposed to a day length of 16 hours at 100 μmol·m-2s-1. Short days were 9 hours at an irradiance level of 180 μmol·m-2s-1 to give the same total daily irradiance (5.8 mol· m-2day-1) as long day conditions. The temperature was maintained at 21° ± 4°C during the day and 18° ± 2°C during night. The observed growth and development responses were similar among the studied cultivars. During the period of 4 to 8 weeks after germination, the seedling height increased at an average rate of 0.7 mm day-1 for plants grown under long days and 0.3 mm day-1 for short day plants. The photoperiodic conditions did not affect the number of emerging leaves. The root development was more proliferate on plants allowed to develop under long days compared to plants exposed to short days during early development.

Photoperiod and population density interact to affect reproductive and immune function in male prairie voles

1996 ◽  
Vol 270 (3) ◽  
pp. R571-R577 ◽  
Author(s):  
R. J. Nelson ◽  
J. B. Fine ◽  
G. E. Demas ◽  
C. A. Moffatt
Keyword(s):  
Population Density ◽  
Immune Function ◽  
High Density ◽  
Adrenal Function ◽  
Day Length ◽  
Low Density ◽  
Prairie Voles ◽  
Extrinsic Factors ◽  
Short Day ◽  
Long Day

Seasonal breeding of rodents is often associated with changes in adrenal function; altered adrenal function could account, in part, for seasonal changes in immune function and, ultimately, influence seasonal fluctuations in survival. Animals commonly monitor the annual change in photoperiod to ascertain the time of year and to make appropriate seasonal adjustments in physiology and behavior. Several extrinsic factors affect reproductive responsiveness to photoperiod. The interaction between population density and reproductive and adrenal responsiveness to photoperiod was assessed in the present experiment. Adult male prairie voles (Microtus ochrogaster) were maintained individually for 10 wk in long [light:dark (LD) 16:8] or short (LD 8:16) photoperiods in rooms with either high (10.96 animals/m3) or low (0.18 animals/m3) population densities. Regardless of population density, short-day voles regressed the size of their reproductive organs; reproductive organ masses were higher in long-day voles housed in high-density compared with low-density rooms. Paired adrenal masses were reduced in short-day voles, but were unaffected by population density; serum corticosterone concentrations were significantly elevated in short-day compared with long-day animals. In both photoperiods, basal blood corticosterone levels were higher in voles from low-density compared with high-density rooms. Splenic masses were unaffected by day length, but were elevated among high-density animals. Similarly, serum immunoglobulin (IgG) levels were elevated among high-density animals. These results suggest that population density per se, in the absence of behavioral interactions, can affect reproductive size, and possibly function, in long-day conditions, and that prairie voles, which are highly social, exhibit higher corticosterone and lower IgG levels in low compared with high densities. These results may be important in understanding arvicoline population fluctuations, as well as improving animal husbandry practices in the lab.

Day length influences proceptive behavior of female prairie voles (Microtus ochrogaster)

1994 ◽  
Vol 55 (6) ◽  
pp. 1163-1165 ◽  
Author(s):  
Christopher A. Moffatt ◽  
Randy J. Nelson
Keyword(s):  
Microtus Ochrogaster ◽  
Day Length ◽  
Prairie Voles

Egg production in Arctic charr (Salvelinus alpinus L.) broodstock: effects of photoperiod on the timing of ovulation and egg quality

1994 ◽  
Vol 72 (2) ◽  
pp. 334-338 ◽  
Author(s):  
C. Gillet
Keyword(s):  
Egg Production ◽  
Egg Quality ◽  
Cold Water ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Day Treatment ◽  
Light Period ◽  
Day Length ◽  
Long Day ◽  
Short Days

Arctic charr were subjected to different photoperiod manipulations applied at several stages of the reproductive cycle to advance or delay ovulation. Spawning was delayed by 6 weeks when the fish were subjected to long days (17 h light: 7 h dark) from midsummer. Ovulations were spread over a period of 2.5 months if fish were maintained under a long-day regime until spawning. When the long-day treatment was stopped in December, ovulations were synchronized to within 1 month. Long days early in the year followed by short days at the beginning of summer advanced spawning by 3 months. Immature, 20-monfh-old fish maintained in constant long days from 1 October started to spawn at the beginning of the following summer, i.e., 6 months before fish kept in a natural light period. The eggs produced in January by females with delayed ovulation were of better quality than those of fish kept in a natural day length in December. This improvement was probably due to a decrease in water temperature from 8 to 6 °C between December and January, since overripening of the ova was reduced when the temperature was decreased. It seems possible that by manipulating the photoperiod, viable eggs can be obtained from Arctic charr broodstock all year round provided the cold-water requirement of spawners is taken into account.

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