scholarly journals Seasonal variation in thyroid activity of turtle Lissemys punctata with respect to annual cycle of reproduction

2010 ◽  
Vol 2 (2) ◽  
pp. 194-199
Author(s):  
Vidya R. Chandavar ◽  
Prakash R. Naik
Keyword(s):  
Seasonal Variation ◽  
Reproductive Cycle ◽  
Annual Cycle ◽  
Seasonal Cycle ◽  
Maximum Size ◽  
Reproductive Period ◽  
Thyroid Activity ◽  
The Relationship

The objective of the present investigation was to study the relationship between thyroid activity and reproductive cycle in turtle Lissemys punctata. The animals were studied in the annual seasonal cycle of reproduction for two consecutive years, which is distinguished into three separate periods namely regenerative, reproductive and recrudescent. The thyroid in L. punctata was observed to be a single pyramid shaped gland, creamy white to reddish-brown in color with lenticular profile. The diameter of the follicle was lowest in regenerative period, whichgradually increased in reproductive period attaining maximum size in recrudescent, where as epithelial height was highest in regenerative period, which gradually decreased in reproductive period reaching minimum in recrudescent period. Thyroid activity varies annually in relation to different phases of reproductive periods.

scholarly journals Reproductive cycle of the mangrove oyster, Crassostrea rhizophorae (Bivalvia: Ostreidae) cultured in a macrotidal high-salinity zone on the Amazon mangrove coast of Brazil

2021 ◽  
Vol 51 (2) ◽  
pp. 113-121
Author(s):  
Ícaro ANTONIO ◽  
Ana SOUSA ◽  
Tiago LENZ ◽  
Izabel FUNO ◽  
Rodolf LOPES ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Cycle ◽  
Condition Index ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Salinity Zone ◽  
Crassostrea Rhizophorae ◽  
Reproductive Events ◽  
The Tropics ◽  
The Relationship

ABSTRACT This study aimed to establish the reproductive cycle of the mangrove oyster, Crassostrea rhizophorae cultured in the macrotidal estuary of the Paciência River, Maranhão state, on the northeastern coast of Brazil, and its relationship with environmental factors. Oysters were collected monthly throughout 2013 for histological analysis of sex ratio, gonadal development and condition index. The sex ratio was 1:1.39 (M:F) and only 5 specimens presented hermaphroditism. The breeding process was continuous throughout the year and mature (IIIA stage) and spawning oysters (IIIB stage) were present in practically all months. Low variation in temperature seemed to be the main factor for the continuity of the reproductive cycle. Besides temperature, the relationship between rainfall, salinity and primary productivity affected the stimulus and timing of reproductive events. The rainy season, with low values of salinity and high values of chlorophyll a and particulate organic matter, appeared to be the main reproductive period, with release of gametes and production and maturation of new gamete cohorts in the short term. In the tropics, where gamete maturation and release seem to be continuous and concomitant, the condition index does not appear to be the best method to assess reserve accumulation peaks and gonadal repletion.

The wool growth response to the annual cycle of grazing intake in Cheviot wethers

1967 ◽  
Vol 69 (3) ◽  
pp. 411-416 ◽  
Author(s):  
J. M. Doney ◽  
J. Eadie
Keyword(s):  
Annual Cycle ◽  
Seasonal Cycle ◽  
Growth Response ◽  
Seasonal Cycles ◽  
Wool Growth ◽  
Periodic Regression ◽  
Free Grazing ◽  
Overall Efficiency ◽  
Relationship Of ◽  
The Relationship

Wool-growth rates were measured at monthly intervals on eight free-grazing Cheviot wethers. Nutrient intakes provided by the upland environment were measured at the same intervals during the 2½ years. Analysis of periodic regression disclosed that both intake and wool growth had similar seasonal cycles but were slightly out of phase. It was concluded that the similarity was largely due to the relationship of both characters with some independent seasonal variable. The seasonal cycle of efficiency of wool growth depends on the time relationship between its two components, but it was found that variation amongst sheep in wool production was greater in the summer months and this depended more on variation in overall efficiency than on variation in grazing intake.

scholarly journals Proliferative and Apoptotic Pathways in the Testis of Quail Coturnix coturnix during the Seasonal Reproductive Cycle

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1729
Author(s):  
Sara Falvo ◽  
Luigi Rosati ◽  
Maria Maddalena Di Fiore ◽  
Federica Di Giacomo Russo ◽  
Gabriella Chieffi Baccari ◽  
...  
Keyword(s):  
Reproductive Cycle ◽  
Second Messengers ◽  
Reproductive Period ◽  
Annual Reproductive Cycle ◽  
Coturnix Coturnix ◽  
Immunohistochemistry Analysis ◽  
17Β Estradiol ◽  
Apoptotic Pathways ◽  
Camp And Cgmp ◽  
Activation Phase

The quail Coturnix coturnix is a seasonal breeding species, with the annual reproductive cycle of its testes comprising an activation phase and a regression phase. Our previous results have proven that the testicular levels of both 17β-estradiol (E2) and androgens are higher during the reproductive period compared to the non-reproductive period, which led us to hypothesize that estrogens and androgens may act synergistically to initiate spermatogenesis. The present study was, therefore, aimed to investigate the estrogen responsive system in quail testis in relation to the reproduction seasonality, with a focus on the molecular pathways elicited in both active and regressive quail testes. Western blotting and immunohistochemistry analysis revealed that the expression of ERα, which is the predominant form of estrogen receptors in quail testis, was correlated with E2 concentration, suggesting that increased levels of E2-induced ERα could play a key role in the resumption of spermatogenesis during the reproductive period, when both PCNA and SYCP3, the mitotic and meiotic markers, respectively, were also increased. In the reproductive period we also found the activation of the ERK1/2 and Akt-1 kinase pathways and an increase in second messengers cAMP and cGMP levels. In the non-reproductive phase, when the E2/ERα levels were low, the inactivation of ERK1/2 and Akt-1 pathways favored apoptotic events due to an increase in the levels of Bax and cytochrome C, with a consequent regression of the gonad.

scholarly journals Spatio-temporal variation in number and production of neustonic and planktonic bacteria inhabiting polluted estuarine harbour channel

2021 ◽  
Vol 203 (9) ◽  
pp. 5547-5559
Author(s):  
Piotr Perliński ◽  
Zbigniew J. Mudryk ◽  
Marta Zdanowicz ◽  
Łukasz Kubera
Keyword(s):  
Seasonal Variation ◽  
Secondary Production ◽  
Seasonal Cycle ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Water Basin ◽  
Planktonic Bacteria ◽  
Microbiological Parameters ◽  
Spatio Temporal ◽  
Number Of Bacteria

AbstractThe aim of this paper was to determine the abundance and secondary production by bacteria inhabiting the surface microlayer and subsurface water in a specific water basin, i.e., polluted estuarine harbour channel. In a 3-year seasonal cycle, the total number of bacteria and their biomass were higher in the surface microlayer (SML) 7.57 × 108cells dm−3 and 15.86 µg C dm−3 than in the subsurface water (SSW) 4.25 × 108cells dm−3 and 9.11 µg C dm−3 of the studied channel. The opposite relationship was noted in the level of the secondary production (SML—37.16 μg C dm−3 h−1, SSW—60.26 μg C dm−3 h−1) in this water basin. According to the analysed microbiological parameters, the total number of bacteria and secondary production varied along the horizontal profile in the water of the studied channel. The total number of bacteria and their secondary production showed the seasonal variation as well.

Population structure and dynamics of the freshwater shrimp Atyaephyra desmarestii (Millet, 1831) in the lower River Minho (NW Portugal)

Crustaceana ◽  
2015 ◽  
Vol 88 (6) ◽  
pp. 657-673 ◽  
Author(s):  
Maria L. Fidalgo ◽  
Paulo Santos ◽  
Cláudia Ferreira ◽  
Andreia Silva
Keyword(s):  
Water Quality ◽  
Reproductive Period ◽  
Specific Knowledge ◽  
Nw Portugal ◽  
Ecological Relevance ◽  
Structure And Dynamics ◽  
Population Structure And Dynamics ◽  
Autumn And Winter ◽  
The Relationship ◽  
Fast Increase

This paper reports population dynamics, growth, and reproductive features ofAtyaephyra desmarestii(Millet, 1831) from the estuary of the River Minho. Also, data were compared to information available from its distribution range. Samples were taken monthly between October 2010 and September 2011. Males were less abundant and smaller than females. The growth pattern showed hardly any increase during the autumn and winter, but a fast increase in size was recorded in spring, followed by slower growth in summer. The life span was 11-12 months. The reproductive period was from April to August, and mean fecundity reached 643 ± 254 eggs/female. Juveniles started to appear in July and a strong recruitment occurred in summer and autumn. The ecological relevance of the shrimp supports the need of obtaining further and more specific knowledge on the relationship between geographical distribution and water quality. Our results coupled with longer time series in different localities will be essential to the conservation of the species.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

A Large Annual Cycle in Ozone above the Tropical Tropopause Linked to the Brewer–Dobson Circulation

2007 ◽  
Vol 64 (12) ◽  
pp. 4479-4488 ◽  
Author(s):  
William J. Randel ◽  
Mijeong Park ◽  
Fei Wu ◽  
Nathaniel Livesey
Keyword(s):  
Annual Cycle ◽  
Seasonal Cycle ◽  
Annual Variation ◽  
Lower Stratosphere ◽  
Vertical Gradient ◽  
Relative Amplitude ◽  
Vertical Layer ◽  
Satellite Measurements ◽  
Tropical Tropopause ◽  
Vertical Gradients

Abstract Near-equatorial ozone observations from balloon and satellite measurements reveal a large annual cycle in ozone above the tropical tropopause. The relative amplitude of the annual cycle is large in a narrow vertical layer between ∼16 and 19 km, with approximately a factor of 2 change in ozone between the minimum (during NH winter) and maximum (during NH summer). The annual cycle in ozone occurs over the same altitude region, and is approximately in phase with the well-known annual variation in tropical temperature. This study shows that the large annual variation in ozone occurs primarily because of variations in vertical transport associated with mean upwelling in the lower stratosphere (the Brewer–Dobson circulation); the maximum relative amplitude peak in the lower stratosphere is collocated with the strongest background vertical gradients in ozone. A similar large seasonal cycle is observed in carbon monoxide (CO) above the tropical tropopause, which is approximately out of phase with ozone (associated with an oppositely signed vertical gradient). The observed ozone and CO variations can be used to constrain estimates of the seasonal cycle in tropical upwelling.

scholarly journals Changes in the thyroid gland during the reproductive cycle of the male vespertilionid bat, Scotophilus heathi

1998 ◽  
Vol 58 (4) ◽  
pp. 707-716 ◽  
Author(s):  
A. KRISHNA ◽  
K. SINGH
Keyword(s):  
Body Weight ◽  
Seasonal Variation ◽  
Thyroid Gland ◽  
Seasonal Change ◽  
Reproductive Cycle ◽  
The Body ◽  
Winter Dormancy ◽  
High Concentration ◽  
Positive Correlation ◽  
Low Concentration

The aim of present study was to compare the changes in thyroid gland with the reproductive cycle of S. heathi. Thyroid showed marked seasonal variation in weight, quantity of colloid and follicular epithelial height, suggesting the thyroid gland to be inactive during quiescence and winter dormancy and active during the time of recrudescence and breeding similarly to the testicular cycle. Plasma thyroxin (T4) concentration showed a significant seasonal change with high concentration during breeding and post-breeding and low concentration during quiescence. However, the T4 concentration increased from breeding to post-breeding phase, when the testes weight was declining. It is suggested that in S. heathi the positive correlation between thyroid and testicular cycles occurs only during the phases of the reproductive cycle when the body weight and testicular activity are also closely correlated.

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