scholarly journals Seasonal variations of pineal involvement in the circadian organization of the ruin lizard Podarcis sicula

1996 ◽  
Vol 199 (5) ◽  
pp. 1189-1194
Author(s):  
A Innocenti ◽  
C Bertolucci ◽  
L Minutini ◽  
A Foà
Keyword(s):  
Pineal Gland ◽  
Seasonal Variations ◽  
Circadian Activity ◽  
Activity Time ◽  
Podarcis Sicula ◽  
Locomotor Behaviour ◽  
Circadian Organization ◽  
Locomotor Rhythms ◽  
Autumn And Winter ◽  
First Time

To establish whether the effects of pinealectomy on circadian locomotor rhythmicity vary with season, we examined, in constant temperature and darkness, the locomotor behaviour of ruin lizards Podarcis sicula collected and subjected to pinealectomy at different times of the year. Changes in the freerunning period in response to pinealectomy were found to be significantly greater in summer than in winter, spring and autumn. Circadian activity time changed significantly in response to pinealectomy only in spring and summer. Furthermore, while pinealectomy was effective in altering the locomotor rhythms of all individual lizards tested in summer, the same surgery was found to leave locomotor rhythmicity of many lizards tested in autumn and winter completely undisturbed. These results demonstrate for the first time in a non-mammalian vertebrate that the pineal gland is centrally involved in determining circadian organization in some seasons and is only marginally involved in others.

Seasonality and role of SCN in entrainment of lizard circadian rhythms to daily melatonin injections

1998 ◽  
Vol 274 (4) ◽  
pp. R1004-R1014 ◽  
Author(s):  
Cristiano Bertolucci ◽  
Augusto Foà
Keyword(s):  
Circadian Rhythms ◽  
Locomotor Behavior ◽  
Suprachiasmatic Nuclei ◽  
Primary Target ◽  
Podarcis Sicula ◽  
Injection Period ◽  
Target Sites ◽  
Locomotor Rhythms ◽  
First Time

To establish whether the capability of daily melatonin injections to entrain circadian rhythms varies with season, we examined in constant conditions the locomotor behavior of lizards Podarcis sicula collected and subjected to daily melatonin injections at different times of the year. Although in summer locomotor rhythms of both pineal-intact and pinealectomized lizards became entrained to the 24-h injection period, in the other seasons their rhythms did not entrain to the injection period. To establish whether the suprachiasmatic nuclei (SCN) mediate summer entrainment of locomotor rhythms to melatonin, we examined the behavioral effects of daily melatonin injections in lizards subjected to either bilateral (SCN-X) or unilateral (USCN-X) ablation of the SCN. SCN-X lizards became behaviorally arrhythmic, and daily melatonin injections did not restore rhythmicity. USCN-X lizards remained rhythmic, and their locomotor rhythms did entrain to the injections. Besides demonstrating for the first time in a vertebrate that daily melatonin injections are capable of entraining circadian rhythmicity in only one season (summer), the present results support the view that the SCN (and not the pineal gland) are the primary target sites of melatonin in the circadian system of P. sicula.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

scholarly journals Seasonal variations of frequency parameters of Earth’s natural pulsed electromagnetic field

2020 ◽  
pp. 199-208
Author(s):  
В.Ф. Гордеев ◽  
В.А. Крутиков ◽  
С.Ю. Малышков ◽  
В.И. Поливач
Keyword(s):  
Electromagnetic Field ◽  
Physical Model ◽  
Seasonal Change ◽  
Seasonal Variations ◽  
Survey Methods ◽  
Additional Stress ◽  
Strained State ◽  
Pulsed Electromagnetic Field ◽  
Pulsed Electromagnetic ◽  
First Time

В результате постоянного мониторинга интенсивности импульсного потока в диапазоне очень низких частот, впервые зарегистрировано сезонное изменение частотных характеристик естественного импульсного электромагнитного поля Земли (ЕИЭМПЗ). Исходя из общепринятых физических представлений о причинах появления литосферной составляющей ЕИЭМПЗ, основанных на механоэлектрических преобразованиях в горных породах, можно предположить, что изменение низкочастотной составляющей ЕИЭМПЗ в среднесуточных вариациях интенсивности сигнала может быть связано с изменением физико-механических свойств и структуры литосферы. Дальнейшие исследования зависимости суточных и сезонных изменений электромагнитных полей в различных частотных диапазонах позволят получить новые знания о механизмах формирования ЕИЭМПЗ, оценить долю литосферной составляющей в структуре этих полей. Прикладным применением поставленных исследований будет оптимизация методов и оборудования раннего оповещения активизации опасных геодинамических процессов, новые критерии оценки напряженно-деформированного состояния горных пород. As a result of the experiment, we have recorded for the first time the seasonal change in frequency parameters of Earth’s natural pulsed electromagnetic field (ENPEMF). This effect once studied thoroughly should allow to further advance a physical model of ENPEMF lithosphere component formation and would help to formulate additional stress-strained state of the rock estimation criteria for geodynamic survey methods

scholarly journals The genus Hyalomma Koch, 1844. I. Reinstatement of Hyalomma (Euhyalomma) glabrum Delpy, 1949 (Acari, Ixodidae) as a valid species with a redescription of the adults, the first description of its immature stages and notes on its biology

2006 ◽  
Vol 73 (1) ◽  
Author(s):  
D.A. Apanaskevich ◽  
I.G. Horak
Keyword(s):  
South Africa ◽  
Ixodid Tick ◽  
Valid Species ◽  
Immature Stages ◽  
Large Herbivores ◽  
Hyalomma Marginatum ◽  
Hyalomma Rufipes ◽  
Autumn And Winter ◽  
First Time ◽  
Preferred Hosts

For nearly 50 years the ixodid tick Hyalomma marginatum turanicum, reputedly introduced into South Africa on imported Persian sheep, has been considered identical to the Asian Hyalomma (Euhyalomma) marginatum turanicum Pomerantzev, 1946. Comparisons of this tick with the Asian H. (E.) m. turanicum and other subspecies of Hyalomma (Euhyalomma) marginatum, however, reveal that it is an old taxon, namely Hyalomma rufipes glabrum Delpy, 1949. It is hereby reinstated as Hyalomma (Euhyalomma) glabrum, and its adults are redescribed and its immature stages described for the first time. The preferred hosts of its adults are large herbivores such as zebras, gems bok and eland, on which it occurs during summer. The preferred hosts of its immature stages are scrub hares and ground-frequenting birds, on which it is present during autumn and winter. Data on its distribution and possible disease relationships are also provided.

Electrophysiological and Anatomical Characterization of PDF-Positive Clock Neurons in the Intact Adult Drosophila Brain

2006 ◽  
Vol 95 (6) ◽  
pp. 3955-3960 ◽  
Author(s):  
Demian Park ◽  
Leslie C. Griffith
Keyword(s):  
Biological Rhythms ◽  
Cell Group ◽  
Resting Membrane Potential ◽  
Electrophysiological Properties ◽  
Drosophila Brain ◽  
A Cell ◽  
Locomotor Rhythms ◽  
Firing Properties ◽  
First Time

Daily biological rhythms in both prokaryotes and eukaryotes are controlled by circadian clocks. In Drosophila, there is a good basic understanding of both the molecular and anatomical components of the clock. In this study we directly measure, for the first time, electrophysiological properties and anatomy of individual filled large lateral PDF-positive clock neurons, a cell group believed to be involved in synchronization of the clock in constant conditions. We find that the large PDF-positive neurons are morphologically homogeneous and that their resting membrane potential is modulated both by the clock and by light inputs. Expression of a leak channel, dORK-ΔC, which has been shown to disrupt circadian locomotor rhythms, hyperpolarizes these neurons, and blocks firing. These data imply that the firing properties of large PDF neurons are both regulated by and critical for clock function.

scholarly journals Spatial and Seasonal Variations of PM Concentration and Size Distribution in Manure-Belt Poultry Layer Houses

2019 ◽  
Vol 62 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Reyna M. Knight ◽  
Xinjie Tong ◽  
Zhenyu Liu ◽  
Sewoon Hong ◽  
Lingying Zhao
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Size Distribution ◽  
Seasonal Variations ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Potential Health ◽  
Significant Difference ◽  
Autumn And Winter ◽  
Mass Concentrations

Abstract. Poultry layer houses are a significant source of particulate matter (PM) emissions, which potentially affect worker and animal health. Particulate matter characteristics, such as concentration and size distribution inside layer houses, are critical information for assessment of the potential health risks and development of effective PM mitigation technologies. However, this information and its spatial and seasonal variations are lacking for typical layer facilities. In this study, two TSI DustTrak monitors (DRX 8533) and an Aerodynamic Particle Sizer (APS 3321) were used to measure PM mass concentrations and number-weighted particle size distributions in two typical manure-belt poultry layer houses in Ohio in three seasons: summer, autumn, and winter. Bimodal particle size distributions were consistently observed. The average count median diameters (mean ±SD) were 1.68 ±0.25, 2.16 ±0.31, and 1.87 ±0.07 µm in summer, autumn, and winter, respectively. The average geometric standard deviations of particle size were 2.16 ±0.23, 2.16 ±0.18, and 1.74 ±0.17 in the three seasons, respectively. The average mass concentrations were 67.4 ±54.9, 289.9 ±216.2, and 428.1 ±269.9 µg m-3 for PM2.5; 73.6 ±59.5, 314.6 ±228.9, and 480.8 ±306.5 µg m-3 for PM4; and 118.8 ±99.6, 532.5 ±353.0, and 686.2 ±417.7 µg m-3 for PM10 in the three seasons, respectively. Both statistically significant (p &lt; 0.05) and practically significant (difference of means &gt;20% of smaller value) seasonal variations were observed. Spatial variations were only practically significant for autumn mass concentrations, likely due to external dust infiltration from nearby agricultural activities. The OSHA-mandated permissible exposure limit for respirable PM was not exceeded in any season. Keywords: Air quality, Particulate matter, Poultry housing, Seasonal variation, Spatial variation.

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

1980 ◽  
Vol 84 (1) ◽  
pp. 83-89 ◽  
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.

Seasonal variations in length of copepods in South Pacific New Zealand waters

1966 ◽  
Vol 17 (2) ◽  
pp. 155 ◽  
Author(s):  
GB Deevey
Keyword(s):  
New Zealand ◽  
Seasonal Variations ◽  
Spring Bloom ◽  
Narrow Temperature Range ◽  
Temperature Range ◽  
Maximal Size ◽  
Cephalothorax Length ◽  
Autumn And Winter ◽  
Cycle Temperature ◽  
Paracalanus Parvus

Measurements of cephalothorax length were made on females and males of Centropages aucklandicus, Acartia clausi, Paracalanus parvus, and Clausocalanus arcuicornis, and on female Calanus australis for the period from April 1964 to May 1965. Centropages aucklandicus and A. clausi increased gradually in length during autumn and winter to maximal size in the spring and were smaller again in summer. Paracalanus parvus was larger in spring and smaller the rest of the year. Calanus australis and C. arcuicornis were large in spring, but during summer they were also large on occasion, possibly because offshore populations had been brought into the area. Length-temperature-phytoplankton correlations showed that in temperate New Zealand waters with a relatively narrow temperature range the seasonal variations in length of all the copepods studied were significantly related to the annual phytoplankton cycle; temperature was an important factor for only two of the species. Some of the species measured are primarily herbivorous whereas others, such as Centropages and Acartia, are probably omnivores. Data are lacking for carnivorous copepods. However, since the spring bloom acts as a stimulus to zooplankton reproduction, it is suggested that all copepods that feed on living food might attain maximal size at around the time of the spring bloom in temperate waters with a relatively narrow temperature range.

scholarly journals Immunolocalization of aromatase P450 in the epididymis of Podarcis sicula and Rattus rattus

2020 ◽  
Vol 64 (1) ◽  
Author(s):  
Luigi Rosati ◽  
Marina Prisco ◽  
Mariana Di Lorenzo ◽  
Maria De Falco ◽  
Piero Andreuccetti
Keyword(s):  
Connective Tissue ◽  
Rattus Rattus ◽  
Reproductive Period ◽  
Myoid Cells ◽  
Podarcis Sicula ◽  
P450 Aromatase ◽  
Key Enzyme ◽  
Tract Function ◽  
Seasonal Breeder ◽  
First Time

The goal of this study was to evaluate P450 aromatase localization in the epididymis of two different vertebrates: the lizard Podarcis sicula, a seasonal breeder, and Rattus rattus, a continuous breeder. P450 aromatase is a key enzyme involved in the local control of spermatogenesis and steroidogenesis and we proved for the first time that this enzyme is represented in the epididymis of both P. sicula and R. rattus. In details, P450 aromatase was well represented in epithelial and myoid cells and in the connective tissue of P. sicula epididymis during the reproductive period; instead, during autumnal resumption this enzyme was absent in the connective tissue. During the non-reproductive period, P450 aromatase was localized only in myoid cells of P. sicula epididymis, whereas in R. rattus it was localized both in myoid cells and connective tissue. Our findings, the first on the epididymis aromatase localization in the vertebrates, suggest a possible role of P450 aromatase in the control of male genital tract function, particularly in sperm maturation.

DECAPEPTIDE LUTEINIZING HORMONE RELEASING HORMONE IN OVINE PINEAL GLAND

1981 ◽  
Vol 91 (3) ◽  
pp. 405-414 ◽  
Author(s):  
JUDY A. KING ◽  
R. P. MILLAR
Keyword(s):  
Pineal Gland ◽  
Molecular Form ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Releasing Hormone ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Autumn And Winter ◽  
Layer Chromatography ◽  
Positively Charged

Ovine pineal gland extracts were examined throughout the year for content and molecular form of immunoreactive (IMR) LH releasing hormone (LH-RH). The content of IMR LH-RH in pineal glands collected in spring and summer was 160–2230 pg/gland, while the content in pineal glands collected in autumn and winter was lower (31–39 pg/gland). Pineal gland IMR LH-RH, purified by affinity and Sephadex G-25 chromatography, yielded displacement curves parallel to those of hypothalamic IMR LH-RH and synthetic LH-RH in radioimmunoassays employing four antisera which require different regions of the decapeptide for effective binding, suggesting considerable similarities in the structure of the molecule. The majority of pineal gland IMR LH-RH behaved identically to hypothalamic IMR LH-RH and synthetic LH-RH on gel filtration, cation exchange chromatography, high-pressure liquid chromatography and cellulose thin-layer chromatography. However, a small amount of a less positively charged LH-RH species was also present in all pineal gland extracts. Our findings indicate that hypothalamic decapeptide LH-RH occurs in the ovine pineal gland.

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