scholarly journals Spermatogenic Waves and Expression of AR and ERs in Germ Cells ofPodarcis sicula

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mariailaria Verderame ◽  
Francesco Angelini ◽  
Ermelinda Limatola
Keyword(s):  
Germ Cells ◽  
Late Summer ◽  
Early Summer ◽  
Podarcis Sicula ◽  
Mating Period ◽  
Late Pachytene ◽  
Seasonal Breeder ◽  
Almost All

Androgens are considered the main hormones that regulate spermatogenesis, but a lot of evidence confers to estrogen a key role in this process. In the testis of the seasonal breeder lizardPodarcis siculawe analyzed by means ofin situhybridization the expression of the androgen receptor (AR) and of the two types,αandβ, of the estrogen receptors (ERs) throughout the three periods of the annual cycle: mating (spring-early summer), postmating-refractory (late summer), and autumnal recrudescence. The results show that during the mating period AR and ERs are expressed in all germ cells present in the tubules from spermatogonia to spermatozoa. During the postmating-refractory period, when only spermatogonia are present in the tubules, almost all express ERs and very few AR mRNA. During the autumnal recrudescence the localization of AR and ERs is the same of the mating period except for the population of the primary spermatocytes. The expression of the investigated receptors is peculiar in these cells that are positive in the middle-late pachytene stage of the meiotic prophase and negative in preleptotene. A possible functional role of the observed differences during spermatogenesis and in the spermatozoa is also discussed.

scholarly journals The Involvement of the Androgen Receptor in the Secretion of the Epididymalcorpusin the LizardPodarcis sicula

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mariailaria Verderame
Keyword(s):  
Androgen Receptor ◽  
Estrogen Receptors ◽  
Expression Pattern ◽  
Crucial Role ◽  
Secretory Activity ◽  
Seasonal Breeding ◽  
Podarcis Sicula ◽  
Mating Period

A crucial role in the maintenance of male reproductive functions is carried out by the androgen through its receptor in balance with the estrogen receptors (ERs). The distribution of the androgen receptor (AR) is well documented in the testis and in the reproductive tissues of mammals but the findings about the AR in nonmammalian vertebrates and in particular in reptiles are very scarce. Here by means ofin situhybridization (ISH) we investigated the AR expression along the epididymal channel (efferent ductules,corpus, andcauda) ofPodarcis siculaduring the mating and nonmating period. The results show that in this seasonal breeding species the AR expression pattern is always constant throughout the epididymis. The administration of estradiol-17βin the mating period does not affect the AR expression but inhibits the secretory activity of the epididymalcorpus. To verify the expression pattern of ERs, we also conducted ISH investigations on adjacent sections with ERs probes. The findings suggest that AR induces the secretory activity in the epithelial cells of the epididymalcorpusand confirm our previous results that showed the role of ERalpha (ERα) as switch off for the secretion of this compartment.

scholarly journals Metallothionein expression and synthesis in the testis of the lizard Podarcis sicula under natural conditions and following estrogenic exposure

2017 ◽  
Author(s):  
Mariailaria Verderame ◽  
Ermelinda Limatola ◽  
Rosaria Scudiero
Keyword(s):  
Reproductive Cycle ◽  
Methodological Approach ◽  
Immunohistochemical Analysis ◽  
Early Summer ◽  
Podarcis Sicula ◽  
Mating Period ◽  
A Cell ◽  
Specific Regulation ◽  
Almost All ◽  
Cellular Defence

Metallothionein (MT) is the main protein involved in the homeostasis of metallic micronutrients and in cellular defence against heavy metals and reactive oxygen species. Found in almost all vertebrate tissues, MT presence and localization in the testis has been controversial. In the present study, by using in situ hybridization and immunohistochemical analysis we assessed the localization of both MT transcript and protein in Podarcis sicula testes during two different phases of the reproductive cycle: the autumnal resumption and the spring-early summer mating period. In addition, with the same methodological approach, we verified the effect of estradiol-17ß and nonylphenol, a potent xenoestrogen, on MT expression and synthesis.  These results, the first collected in a non-mammalian oviparous vertebrate, demonstrated that the expression profile of MT mRNA and protein changes during the reproductive cycle. In the fall resumption, MT transcripts are absent in spermatogonia and present in all the other cells of tubules, including spermatozoa; vice versa, the MT protein is evident only in spermatozoa and somatic cells. In the mating period, both MT transcripts and proteins are present in spermatogonia, spermatocytes and spermatids, whereas in the spermatozoa only the proteins are detected, thus suggesting that the MTs translated in the earlier germinal stages are stored up to spermatozoa. Results also demonstrated that in lizard testis the expression of MT gene undergoes a cell-specific regulation after estrogenic exposure; the possible role and the mechanism by which this regulation occurs have been discussed.

Gonadal expression of c-kit encoded at the W locus of the mouse

Development ◽  
1990 ◽  
Vol 110 (4) ◽  
pp. 1057-1069 ◽  
Author(s):  
K. Manova ◽  
K. Nocka ◽  
P. Besmer ◽  
R.F. Bachvarova
Keyword(s):  
In Situ Hybridization ◽  
Germ Cells ◽  
Leydig Cells ◽  
Interstitial Tissue ◽  
Type B ◽  
Age Dependence ◽  
Oocyte Growth ◽  
Adult Mice

Recently, it has been shown that the c-kit proto-oncogene is encoded at the white spotting (W) locus in mice. Mutations of this gene cause depletion of germ cells, some hematopoietic cells and melanocytes. In order to define further the role of c-kit in gametogenesis, we have examined its expression in late fetal and postnatal ovaries and in postnatal testis. By RNA blot analysis, c-kit transcripts were not detected in late fetal ovaries but appeared at birth. The relative amount reached a maximum in ovaries of juvenile mice, and decreased in adult ovaries. c-kit transcripts were present in increasing amounts in isolated primordial, growing and full-grown oocytes, as well as in ovulated eggs. Little was detected in early 2-cell embryos and none in blastocysts. In situ hybridization revealed c-kit transcripts in a few oocytes of late fetal ovaries and in all oocytes (from primordial to full-grown) in ovaries from juvenile and adult mice. Expression was also observed in ovarian interstitial tissue from 14 days of age onward. Using indirect immunofluorescence, the c-kit protein was detected on the surface of primordial, growing and full-grown oocytes, as well as on embryos at the 1- and 2-cell stages; little remained in blastocysts. In situ hybridization analysis of testes from mice of different ages demonstrated expression in spermatogonia from 6 days of age onward. Using information provided by determining the stage of the cycle of the seminiferous epithelium for a given tubule and by following the age dependence of labeling, it was concluded that the period of expression of c-kit extends from at least as early as type A2 spermatogonia through type B spermatogonia and into preleptotene spermatocytes. Leydig cells were labelled at all ages examined. The expression pattern in oocytes correlates most strongly with oocyte growth and in male germ cells with gonial proliferation.

scholarly journals Exploring the Role of Estrogens in Lizard Spermatogenesis through the Study of Clomiphene and FSH Effects

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Mariailaria Verderame ◽  
Rosaria Scudiero ◽  
Ermelinda Limatola
Keyword(s):  
Natural Condition ◽  
Biological Process ◽  
Clomiphene Citrate ◽  
Active Role ◽  
Sex Hormone ◽  
Podarcis Sicula ◽  
Mating Period ◽  
Agonist And Antagonist ◽  
Experimental Approaches

Spermatogenesis is a fascinating biological process aiming to generate haploid spermatozoa from diploid spermatogonia through a specific hormonal network between gonadotropins and steroids. Increasing evidence suggests that the primary female sex hormone estrogen plays an active role in this process. This research points out on the role of estrogen during lizard spermatogenesis by using three experimental approaches: (1) exposure to an analogue of nonsteroidal estrogen as Clomiphene citrate that acts both as estrogen agonist and antagonist; (2) exposure to the gonadotropin FSH; and (3) exposures to FSH followed by Clomiphene. Histological and immunohistochemical results demonstrate that in the lizard Podarcis sicula during the mating period, Clomiphene as well as FSH determines the breakdown of spermatogenesis and the epididymal regression, presumably through estrogens input as indirectly demonstrated by the appearance of ERα and vitellogenin in the liver. The ability of Clomiphene to restore the gonadal natural condition after FSH treatment is also demonstrated. Finally, data indicate that lizard testis and epididymis control their morphophysiology regulating the intracellular presence of ERα.

scholarly journals The origin and antigen-dependent distribution of IgA-containing cells in the intestine.

1978 ◽  
Vol 148 (5) ◽  
pp. 1146-1160 ◽  
Author(s):  
A J Husband ◽  
J L Gowans
Keyword(s):  
Lamina Propria ◽  
Thoracic Duct ◽  
Cellular Response ◽  
Time Course ◽  
Thoracic Duct Lymph ◽  
Iga Antibody ◽  
Time Course Study ◽  
Almost All

The aims of this paper were to establish the origin of cells producing IgA antibody to cholera toxoid in the lamina propria of the small intestine and to define the role of antigen in their distribution. The use of Thirty-Vella loops made it possible to restrict antigenic challenge to a defined segment of the intestine in rats which had been primed i.p. with toxoid in Freund's complete adjuvant. The anti-toxin-containing cells (ACC) which appeared in the draining thoracic duct lymph after challenge of a loop were almost all of IgA specificity and their numbers were proportional to the length of intestine exposed to antigen. The abolition of this cellular response which occurred when Peyer's patches (PP) were removed from a loop before challenge and the failure of mesenteric lymphadenectomy significantly to affect the response indicated that ACC originated exclusively from PP. Cell transfer studies showed that although nonrecirculating large lymphocytes gave rise to ACC in the lamina propria, some of the recirculating small lymphocytes also developed subsequently into ACC. Counts of ACC in the lamina propria of challenged loops were consistently greater than in nonchallenged loops although some ACC were always present in the latter. However, a time-course study on the appearance of ACC in the lamina propria of cannulated rats given a single dose of thoracic duct lymphocytes from immunized donors demonstrated that ACC continued to accumulate and persist in challenged loops but only appeared transiently in nonchallenged loops. These transients did not migrate from the lamina propria back into the lymph and they presumably died in situ. The increase in the number of ACC in loops which had been challenged with antigen was probably due both to cell division in the lamina propria and to the development of new ACC from recirculating lymphocytes which had been recruited into the loop. Thus, the cells which give rise to intestinal ACC can migrate into the lamina propria independently of antigen, but antigen has a profound effect on the location, magnitude, and persistence of the response.

Seasonal changes in leaf and stem loline alkaloids in meadow fescue

2011 ◽  
Vol 62 (3) ◽  
pp. 261 ◽  
Author(s):  
Brian Patchett ◽  
Ravi Gooneratne ◽  
Lester Fletcher ◽  
Bruce Chapman
Keyword(s):  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Sharp Decline ◽  
Meadow Fescue ◽  
Accumulation Pattern ◽  
Loline Alkaloids

Leaf and stem loline alkaloid concentration in 10 European meadow fescue (Festuca pratensis Huds.) lines grown in a field in Canterbury, New Zealand, were determined in samples collected six times between early spring 2004 and late autumn 2005. Significant differences in loline alkaloid concentrations were noted between lines and between harvest times. Higher total loline alkaloid concentrations (up to 4990 µg g–1) were found in stems compared to leaf (up to 1770 µg g–1). However, the seasonal accumulation pattern of different loline alkaloid concentrations in leaf and stem varied. In most lines, stem loline concentration peaked sharply in late spring and declined during early summer and autumn. The seasonal pattern of leaf loline alkaloid concentration followed the stem concentration except for a sharp decline in early summer followed by an increase in late summer. In most instances, the concentration of N-formyl loline was the highest > N-acetyl loline > N-acetyl norloline > N-methyl loline. The possible role of stem and leaf loline alkaloids to deter pasture-feeding insects is briefly discussed.

In Situ Measures of Dissolved Organic Carbon Flux in a Rural Stream

1984 ◽  
Vol 41 (6) ◽  
pp. 964-973 ◽  
Author(s):  
Frank T. Kuserk ◽  
Louis A. Kaplan ◽  
Thomas L. Bott
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Removal Rate ◽  
Algal Growth ◽  
Late Summer ◽  
Early Summer ◽  
Order Stream ◽  
Organic Carbon Flux ◽  
Order Of Magnitude

Dissolved organic carbon (DOC) dynamics were measured in a second-order stream located in a pasture in southeastern Pennsylvania. In situ measurements made at six stations in early summer showed a diel patern of net DOC release from the streambed communities with predawn minima and afternoon maxima. When an 18-m section of the stream was covered with black plastic for 1 mo to exclude algal growth and measures were repeated in late summer, a net removal of DOC occurred in the covered section, while in an adjacent uncovered section DOC was released. When a bovine manure extract was introduced into the covered section, the DOC removal rate increased by more than an order of magnitude. Jewel-weed (Impatiens capensis L.) extract also elicited an elevated rate of DOC removal. When these extracts were added individually to microcosms, removal rates in the dark were 57 and 65% of the in situ uptake estimates for the manure extract and leachate, respectively. Abiotic controls showed that nearly all of the DOC removal was biotic uptake. DOC flux measurements in a third-order section of White Clay Creek, located on an adjacent watershed, also revealed a net DOC release from the uncovered streambed. Introduction of a bovine manure extract elicited a DOC removal rate an order of magnitude less than in the pasture stream. A companion microcosm experiment yielded an uptake rate that was 178% of the in situ estimate.

scholarly journals Gh is produced by the testis of Japanese eel and stimulates proliferation of spermatogonia

Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 869-877 ◽  
Author(s):  
Chiemi Miura ◽  
Yosuke Shimizu ◽  
Maho Uehara ◽  
Yuichi Ozaki ◽  
Graham Young ◽  
...  
Keyword(s):  
Steroid Hormones ◽  
Germ Cells ◽  
Physiological Role ◽  
Somatic Growth ◽  
Japanese Eel ◽  
Expression Of Genes ◽  
Genes Encoding

Gh plays important roles in development, somatic growth and gametogenesis in vertebrates. To determine the physiological role of Gh in reproduction in male teleosts, the expression of genes encoding Gh and the two Gh receptors (Ghrs) during spermatogenesis, and the action of Ghin vitrowas examined using the Japanese eel (Anguilla japonica).gh,ghr1andghr2mRNA transcripts were detected in all spermatogenic stages.In situhybridization showed the presence ofghr1andghr2mRNA in the germ cells. Immunohistochemistry using an antiserum against eel Gh indicated that Gh protein was localized to Sertoli cells surrounding the germ cells in early spermatogenesis. Recombinant eel Gh induced spermatogonial proliferation in a testis organ culture system, an effect that was independent from the production of steroid hormones or Igf1. This study identifies a role for eel Gh in the regulation of early spermatogenesis, particularly in the mitotic phase of spermatogenesis, that is not mediated by either steroid hormones or Igf1 production.

Michael Kelly, Hilary Footitt, Myriam Salama-Carr (eds.): The Palgrave Handbook of Languages and Conflict

2020 ◽  
Vol 55 (2) ◽  
Author(s):  
Ľubomír Zvada
Keyword(s):  
International Relations ◽  
Foreign Languages ◽  
Military Operations ◽  
Sources Of Information ◽  
War And Peace ◽  
Interdisciplinary Field ◽  
Speakers Of Other Languages ◽  
War And Conflict ◽  
Almost All

This Handbook maps the contours of an exciting and burgeoning interdisciplinary field concerned with the role of language and languages in situations of conflict. It explores conceptual approaches, sources of information that are available, and the institutions and actors that mediate language encounters. It examines case studies of the role that languages have played in specific conflicts, from colonial times through to the Middle East and Africa today. The contributors provide vibrant evidence to challenge the monolingual assumptions that have affected traditional views of war and conflict. They show that languages are woven into every aspect of the making of war and peace, and demonstrate how language shapes public policy and military strategy, setting frameworks and expectations. The Handbook's 22 chapters powerfully illustrate how the encounter between languages is integral to almost all conflicts, to every phase of military operations and to the lived experiences of those on the ground, who meet, work and fight with speakers of other languages. This comprehensive work will appeal to scholars from across the disciplines of linguistics, translation studies, history, and international relations; and provide fresh insights for a broad range of practitioners interested in understanding the role and implications of foreign languages in war.

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