The reproductive cycle of the firetail gudgeon, Hypseleotris galii II. Seasonal histological changes in the testes

1973 ◽  
Vol 21 (1) ◽  
pp. 67 ◽  
Author(s):  
NJ Mackay
Keyword(s):  
Water Temperature ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Meiotic Division ◽  
Steroid Biosynthesis ◽  
Histological Changes ◽  
Late Autumn

Seasonal histological changes in the testis of H.galii are described. Spermatogenesis follows the cystic pattern common in anamniotes. Mitotic increase in spermatogonia occurs in late autumn, when photoperiod and water temperature are falling. The meiotic division of spermatocytes and subsequent changes of spermatogenesis are initiated when photoperiod and water temperature are rising and continue through the breeding season (November-January) until March, when water temperature begins to fall rapidly. The possible role of cholesterol-positive lobule boundary cells in steroid biosynthesis is discussed.

The reproductive cycle of the firetail gudgeon, Hypseleotris galii I. Seasonal histological changes in the ovary

1973 ◽  
Vol 21 (1) ◽  
pp. 53 ◽  
Author(s):  
NJ Mackay
Keyword(s):  
Breeding Season ◽  
Reproductive Cycle ◽  
Growth Phase ◽  
Steroid Biosynthesis ◽  
Histological Changes ◽  
Primary Growth ◽  
Fish Oocytes

Seasonal histological changes in the ovary of H. galii are described. Oogenesis occurs in January and February, at the end of the breeding season. Evidence suggests that oogenesis continues in senile (post-reproductive) fish. Oocytes in the primary growth phase grow throughout the winter months. Vitellogenesis commences in August, and fish mature by November. During the breeding season (November-January) females ovulate and spawn repeatedly. Mature oocytes remaining after the breeding season become atretic. The fate of follicular derivatives and their possible role in steroid biosynthesis is discussed.

Studies on the marsupial glider, Schoinobates volans (Kerr) I. Reproduction

1969 ◽  
Vol 17 (4) ◽  
pp. 625 ◽  
Author(s):  
RFC Smith
Keyword(s):  
Natural Population ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Reproductive System ◽  
Sexual Maturity ◽  
Field Data ◽  
Reproductive Organs ◽  
Female Reproductive System ◽  
Histological Changes ◽  
Second Year

Field data were obtained during the period September 1962-January 1965 from 710 greater gliders, S. volans, in a natural population. Histological changes were observed in the reproductive tracts of another 129 animals shot during this period. S. volans has a short breeding season in March, April, and May, after which involution of the reproductive organs occurs in both sexes. The species is monovular and polyoestrous. Sexual maturity is attained by both sexes in the second year, following which breeding probably occurs annually. The female reproductive system shows several primitive and anomalous features, among which is the retention of the Wolffian ducts in the adult. The histology of ovaries, uteri, and vaginae at various stages of the reproductive cycle is briefly described.

scholarly journals Helminth Interactions with Bacteria in the Host Gut Are Essential for Its Immunomodulatory Effect

2021 ◽  
Vol 9 (2) ◽  
pp. 226
Author(s):  
Milan Jirků ◽  
Zuzana Lhotská ◽  
Lucia Frgelecová ◽  
Oldřiška Kadlecová ◽  
Klára Judita Petrželková ◽  
...  
Keyword(s):  
Protective Effect ◽  
Intestinal Inflammation ◽  
Hymenolepis Diminuta ◽  
Clinical Parameters ◽  
Th2 Response ◽  
Histological Changes ◽  
Immunological Markers ◽  
Bacterial Microbiota ◽  
Inflammatory Effect

Colonization by the benign tapeworm, Hymenolepis diminuta, has been associated with a reduction in intestinal inflammation and changes in bacterial microbiota. However, the role of microbiota in the tapeworm anti-inflammatory effect is not yet clear, and the aim of this study was to determine whether disruption of the microflora during worm colonization can affect the course of intestinal inflammation. We added a phase for disrupting the intestinal microbiota using antibiotics to the experimental design for which we previously demonstrated the protective effect of H. diminuta. We monitored the immunological markers, clinical parameters, bacterial microbiota, and histological changes in the colon of rats. After a combination of colonization, antibiotics, and colitis induction, we had four differently affected experimental groups. We observed a different course of the immune response in each group, but no protective effect was found. Rats treated with colonization and antibiotics showed a strong induction of the Th2 response as well as a significant change in microbial diversity. The microbial results also revealed differences in the richness and abundance of some bacterial taxa, influenced by various factors. Our data suggest that interactions between the tapeworm and bacteria may have a major impact on its protective effect.

scholarly journals Concerning the Role of Lanosterol and Cycloartenol in Steroid Biosynthesis

1971 ◽  
Vol 246 (12) ◽  
pp. 3967-3976
Author(s):  
Geoffrey F. Gibbons ◽  
L. John Goad ◽  
T.W. Goodwin ◽  
William R. Nes
Keyword(s):  
Steroid Biosynthesis

An Investigation of the Role of the Hypothalamus in the Reproductive Cycle of the Cat

1966 ◽  
Vol 25 (2) ◽  
pp. 140-152 ◽  
Author(s):  
Earle E. Crandall ◽  
Robert C. Bahn ◽  
Edward C. Clark
Keyword(s):  
Reproductive Cycle

scholarly journals Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula

Reproduction ◽  
2001 ◽  
pp. 803-808 ◽  
Author(s):  
L Assisi ◽  
V Botte ◽  
A D'Aniello ◽  
MM Di Fiore
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Reproductive Cycle ◽  
Catalytic Properties ◽  
Ovarian Tissue ◽  
Experimental Treatment ◽  
Tissue Homogenate ◽  
Aromatase Activity

The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.

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