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1

Variation in the ovarian and plasma progesterone and estradiol levels of the domestic hen during a pause in laying

100%
Proszkowiec M., Rzasa J.
Folia Biologica
|
2001
|
vol. 49
|
issue 3-4
285-289
EN
Little is known about the physiological events occurring in the chicken ovary during a pause in laying, therefore the aim of the present study was to examine changes in sex steroid concentration in the follicle wall and blood plasma during cessation of egg laying. The experiment was performed on laying Isa Brown hens. Control hens were fed ad libitum whereas the experimental ones were subjected to a pause in laying by complete food deprivation for 5 days and water deprivation on 3 day followed by feeding every second day up to 9 day and then ad libitum. Blood samples were taken from the wing vein each day. The hens were decapitated on day 3, 6, 9, and 16. The ovary was isolated and the following follicles were dissected: white (1-2; 2-4; 4-6; 6-8 mm) and yellow preovulatory ones (F1-F3). Progesterone and estradiol were measured in the follicle wall and blood plasma by RIA methods. The hens stopped egg laying on day 4 and began egg restoration on day 14 of the experiment. Cessation of egg laying was preceded by a decrease in estradiol and progesterone levels in the ovary as well as in the blood plasma. The plasma level of these steroids began to increase 7 days before the start of egg restoration. Autopsy of the ovary showed that the atrophy of the chicken yellow preovulatory follicles during the pause in laying was accompanied by a significant increase in the total number of white follicles.
2

Expression of follicle-stimulating hormone receptor (FSHR) mRNA in the ovary of Zi geese during developmental and egg laying stages

100%
Kang B., Jiang D. M., Zhou R. J., Yang H. M.
Folia Biologica
|
2010
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vol. 58
|
issue 1-2
61-66
EN
In order to evaluate the expression profile of follicle-stimulating hormone receptor (FSHR) mRNA in the ovary of Zi geese during developmental and egg laying stages, the expression levels of FSHR mRNA in the ovary of Zi geese at the ages of 1 day, 1, 2, 3, 4, 5 and 8 months (n=8, respectively) were examined by quantitative real-time PCR (qRT-PCR). The results showed that FSHR mRNA expression was greater at the age of 1 to 5 and 8 months compared to expression at day 1 (P<0.05). Particularly, the expression of FSHRmRNA at 4, 5 and 8months was much greater, 1.86+_0.14, 3.50+-0.19 and 5.11+-0.27 fold, respectively, compared to expression at day 1 (P<0.01). The level of FSHR mRNA expression at 1, 2 and 3 months was 1.35+-0.12, 1.31+-0.05 and 1.28+-0.09 fold greater, respectively, compared to day 1 (P<0.05). The results indicate that the expression of FSHR mRNA remains at a stable level during the early developmental stage, and increases initially from 4 months until the egg laying stage. In addition, these results support the possibility that FSHR plays a pivotal role in mediating the response of the goose ovary to follicle-stimulating hormone during the developmental and egg laying stages, and especially during the latter.
3

Expression of alpha and beta estrogen receptors in the chicken ovary

100%
Hrabia A., Wilk M., Rzasa J.
Folia Biologica
|
2008
|
vol. 56
|
issue 3-4
187-191
EN
The role of estrogens in hen reproduction is well established. However, the distribution of estrogen receptors in the chicken ovary is unknown. Therefore, the mRNA expression of alpha (ERalpha) and beta (ERbeta) estrogen receptors was examined within the ovaries of laying hens. Expression of ERs was determined by RT-PCR analysis. The presence of ERalpha and ERbeta mRNAs was found in the ovarian stroma and white, yellowish, small yellow and the largest preovulatory (F3-F1) follicles. ERalpha and ERbeta mRNAs were detected in the granulosa and theca layers of the walls of preovulatory follicles. The expression of ERalpha mRNA was markedly higher than ER? mRNA in all examined ovarian compartments. Within the ovary, the relative expression of both ER mRNAs depends on the follicular diameter and the layer of the follicular wall. The results demonstrate the expression of both ERalpha mRNA and ERbeta mRNA in all compartments of the chicken ovary, suggesting different pathways of estrogen action in the avian ovary. Much higher expression of ERalpha mRNA indicates that this form of estrogen receptor is predominant in the chicken ovary. The clarification of the mechanism of ER? and ER? participation in the ovarian functions of birds necessitates further experiments examining ERs at the protein level.
4

Bcl-2 proteins in ovarian apoptosis

100%
Opiela J., Katska-Ksiazkiewicz L.
Biotechnologia
|
2006
|
issue 1
90-96
EN
Members of the Bcl-2 family are considered principal players in the cascade of events that activate or inhibit apoptosis. Recent evidence strongly supports fundamental role of Bcl-2 and related proteins in regulating ovarian cell death. This article will provide an overview of the current knowledge regarding Bcl-2 proteins in programmed cell death in development of the ovary and the postnatal ovarian cycles.
5

Serotonin content in the wall of preovulatory and postovulatory follicles of the domestic hen

100%
Paczoska-Eliasiewicz H., Rzasa J.
Folia Biologica
|
1995
|
vol. 43
|
issue 1-2
75-79
EN
Serotonin (5-HT) level in the 4 largest preovulatory (F4-F1) and 2 postovulatory follicles (POF1-POF2) was determined spectrofluorometrically.During the final, most rapid phase of follicular development, 5-HT content in the preovulatory follicles wall increase gradually, reaching the highest level 0.5 before ovulation.After ovulation 5-HT content in postovulatory follicles rapidly decreased.The results suggest that 5-HT is involved in ovarian functions like folicular development and ovulaton in the domestic hen.
6

Structure and development of ovaries in the weevil, Anthonomus pomorum (Coleoptera, Polyphaga). II. Germ cells of the trophic chamber

88%
Swiatek P.
Folia Biologica
|
2002
|
vol. 50
|
issue 3-4
153-163
EN
The analysis of the germ cell cluster formation in Anthonomus pomorum (Coleoptera, Polyphaga, Curculionidae) has revealed that both linear and branched clones of cystocytes occur in the pupa stage. In the branched clones a poorly developed polyfusome is formed and cystocytes with maximally 3 intercellular bridges were found. In the linear clones the polyfusomes are absent. Further divisions of cystocytes produce exclusively linearly arranged cells. Just after metamorphosis (Imago-A stage), the process of the germ cell membrane reduction starts. Only 2 groups of cells retain cell membranes: i.e the most anteriorly localized group of cystocytes and the posteriorly located presumptive oocytes. The former cells divide mitotically during the summer. As a result an anterior-posterior gradient of the syncytialization process arises in the Imago-B stage (females preparing for hibernation). In the sexually mature females (Imago-C) the trophic chamber consists of a huge syncytial area with numerous nurse cell nuclei embedded in a common cytoplasm, and posteriorly located young oocytes surrounded by prefollicular cells. In the light of recent hypothesis concerning the germ cell cluster formation and telotrophy anagenesis in Polyphaga the significance of the presented results is discussed.
7

Effect of 9-cis retinoic acid (RA) on sex hormone secretion and RA receptor expression in chicken ovarian follicles

88%
Pawlowska K., Sechman A., Suchanek I., Grzegorzewska A., Rzasa J.
Folia Biologica
|
2008
|
vol. 56
|
issue 1-2
65-72
EN
Several lines of evidence indicate that retinoids, derivates of vitamin A, affect reproductive function in birds, however, the mechanism of their action in the ovary is still unknown. Therefore, the present study was designed (i) to show whether in the domestic hen 9-cis retinoic acid (9-cis RA), one of the retinoids, influences steroid secretion in vitro by white and yellow chicken ovarian follicles, and (ii) to detect expression of retinoic acid RXR receptor mRNA in these follicles. The white follicles (small: 1-4 mm, medium: 4-6 mm and large 6-8 mm in diameter) and the three largest yellow preovulatory follicles (F3-F1; 25-37 mm) were isolated from the ovary 3 h before ovulation. The granulosa layer was separated from the theca layer in the preovulatory follicles, which were subsequently divided into 4 equal pieces. The isolated whole white follicles or parts of the granulosa or theca layers were incubated for 24 h at 38oC in Eagle's medium in the following 4 groups: control, ovine LH (oLH; 10 ng/ml), 9-cis RA (100 ng/ml) and 9-cis RA + oLH. After incubation, the medium was collected for estradiol (E2) and progesterone (P4) determination while tissues were saved for protein assay. It was found that 9-cis RA affects steroid secretion from chicken ovarian follicles. It decreased E2 secretion from white follicles and from the theca layer of the two largest (F2 and F1) preovulatory follicles. 9-cis RA had no effect on oLH-stimulated E2 secretion by the white follicles and yellow F2 and F1 follicles, but it diminished E2 secretion by F3 follicles. As regards P4, the effect of 9-cis RA was opposite; it increased P4 secretion from the granulosa layer of all preovulatory follicles. 9-cis RA did not change oLH-stimulated P4 secretion by granulosa layers of F3 and F2 follicles, however, it inhibited oLH-enhanced P4 secretion from the F1 granulosa layer. In a separate experiment, the presence of mRNA encoding RXR was found in the stroma and all follicles of the chicken ovary by means of the RT-PCR technique. The results indicate that retinoids, acting by specific nuclear receptors, are modulators of follicular steroidogenesis in the chicken ovary.
8

Microsporidia infect the Liophloeus lentus (Insecta, Coleoptera) ovarioles, developing oocytes and eggs.

88%
Swiatek P., Gorkiewicz T.
Folia Biologica
|
2006
|
vol. 54
|
issue 1-2
61-67
EN
In the ovarioles of Liophloeus lentus (Insecta, Coleoptera, Curculionidae) two types of bacteria and parasitic microorganisms belonging to Microsporidia have been found. This study shows that the different microsporidian life stages (meronts, sporonts, sporoblasts and spores) infect the outer ovariole sheath, trophic chambers, follicular cells, late previtellogenic and vitellogenic oocytes and eggs. In trophic chambers the parasites are very abundant and are distributed unevenly, i.e. their large mass occupies the syncytial cytoplasm between the nurse cell nuclei, whereas the neck region of the trophic chamber (which houses young oocytes, prefollicular cells and trophic cords) is almost free of parasites. The developing oocytes and eggs contain a lower number of parasites which are usually distributed in the cortical ooplasm. The gross morphology of the ovaries is similar in infected and non-infected specimens. Similarly, the presence of a parasite seems to not disturb the course of oogensis. The only difference was found in the ultrastructure of mitochondria in young previtellogenic oocytes. In the infected females they are unusual i.e. bigger and spherical with tubullar cristae, whereas in the non-infected insects they are elongated and have lamellar cristae. As oogenesis progresses the unusual mitochondria rapidly change their morphology and become similar to the mitochondria in non-infected females. Taking into account the distribution of parasites within the ovarioles, it is suggested that they infect growing oocytes via outer ovariole sheath and follicular epithelium rather than via trophic cords.
9

Structure and development of ovaries in the weevil, Anthonomus pomorum (Coleoptera, Polyphaga). I. Somatic tissues of the trophic chamber

88%
Swiatek P.
Folia Biologica
|
2001
|
vol. 49
|
issue 3-4
215-224
EN
In developing ovarioles of Anthonomus pomorum (Coleoptera, Polyphaga, Curculionidae) the trophic chambers (tropharia) are relatively large and consist of clusters (clones) of germ cells and various somatic tissues. Each ovariole is enclosed within an outer epithelial sheath (tunica externa). Throughout the pupal phase, the growth of this sheath is accelerated and precedes the development of the rest of the ovariole. As a result, the epithelial sheath proliferates anteriorly and forms an elongated ?sleeve? that during the later stages of development becomes gradually filled by the growing tropharium. In the early pupal stage, a few terminal filament cells are observed in contact with the anterior end of the tropharium. These cells are separated from the rest of the trophic chamber by a transverse septum, which maintains continuity with the basal lamina. Beneath the basal lamina there is a layer of inner sheath cells, whereas inside the tropharium there are interstitial cells. These two types of cell differ morphologically in a mature ovary but they retain, until the end of the imago-B stage, a similar ultrastructure testifying to their common origin. At the posterior end of the tropharium, from the imago-B stage on, many young oocytes, surrounded by prefollicular cells, are observed. This is the so-called neck region of the tropharium. Extraction with Triton X-100 detergent showed that in a mature trophic chamber there are only individual microtubules arranged along the projections of interstitial cells. This indicates that the cytoskeleton elements (microfilaments and microtubules) participate only to a very limited extent in the spatial organisation of the tropharium in A. pomorum.
10

Time and reproductive phase-dependent effects of exogenous melatonin on the pineal gland and ovary of a nocturnal bird, the indian spotted owlet, Athene brama

75%
Guchhait P., Haldar C.
Folia Biologica
|
2000
|
vol. 48
|
issue 3-4
91-96
EN
In a tropical nocturnal bird, the Indian spotted owlet, Athene brama, the intraperitonial injection of an identical amount (20mg/ 100 g b. wt/ day) of exogenous melatonin (MEL) for 15 consecutive days increased the pineal weight and plasma MEL level in sexually active birds while it decreased them in inactive birds more potently when injected in the evening (18.30-19.30 h) rather than the morning (0500-0600 h). On the other hand, more efficiently than the morning hour treatment, the evening hour MEL injection decreased the ovary weight and plasma estradiol and progesterone levels both in sexually active and inactive birds, but more potently in active than inactive birds. Thus, the exogenous MEL showed the time and reproductive phase dependent effects on the pineal gland and the ovary of this nocturnal bird.
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