scholarly journals ELUCIDATING THE GONADAL DEVELOPMENT AND SEX DIFFERENTIATION OF THE RICE PADDY EEL, Monopterus albus (Zuiew, 1993), BASED ON GONADAL HISTOMORPHOLOGY AND STEROID HORMONE LEVELS

2021 ◽  
Vol 40 (3) ◽  
pp. 18-27
Author(s):  
Dulce Marie Pili Nisperos ◽  
Gliceria B. Ramos
Keyword(s):  
Steroid Hormones ◽  
Sex Differentiation ◽  
Rice Paddy ◽  
Gonadal Development ◽  
The Philippines ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reproductive Characteristic ◽  
Monopterus Albus ◽  
Fish Samples ◽  
Concentration Levels

The establishment and survival of the population of species in their breeding ground can be attributed to the species’ reproductive characteristic and capacity. The Monopterus albus species is an introduced fish in the Philippines. It is a protogynous hermaphrodite which has a natural ability for sex reversal. This study describes the histomorphology of the different stages of gonadal maturation and determines the concentration levels of the steroid hormones 17ß-estradiol (E2) and testosterone (T) in the blood plasma. These aim to a further understanding on the gonadal development and sex differentiation of the rice paddy eel as a hermaphroditic fish. Fish samples were collected randomly from farm ponds located in three provinces within the island of Luzon, Philippines. The sexual identity of the fish was categorized based on the presence or absence of ovarian and testicular tissues. Histological analysis of the gonad showed that immature, maturing-matured female gonad exhibited ovarian tissues of varying stages. The intersex gonad showed the existence of both ovarian and testicular tissues. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration levels of gonadal steroid hormones. Differences in the concentration levels of the two hormones were evident across all the stages of gonad maturation. The functional role of these hormones in vitellogenesis and spermatogenesis leads to the development of this sex-changing gonads. This reproductive characteristic contributes to our understanding of the reproductive success of hermaphroditic fish.

scholarly journals LC–MS/MS Analysis of Ciguatoxins Revealing the Regional and Species Distinction of Fish in the Tropical Western Pacific

2021 ◽  
Vol 9 (3) ◽  
pp. 299 ◽  
Author(s):  
Naomasa Oshiro ◽  
Takumi Tomikawa ◽  
Kyoko Kuniyoshi ◽  
Akira Ishikawa ◽  
Hajime Toyofuku ◽  
...  
Keyword(s):  
Fish Species ◽  
The Philippines ◽  
Western Pacific ◽  
Tropical Region ◽  
Northern Coast ◽  
Coastal Regions ◽  
Main Island ◽  
Tropical Western Pacific ◽  
The Pacific ◽  
Fish Samples

Ciguatera fish poisoning (CFP) is one of the most frequently reported seafood poisoning diseases. It is endemic to the tropical region and occurs most commonly in the regions around the Pacific Ocean, Indian Ocean, and Caribbean Sea. The principal toxins causing CFP are ciguatoxins (CTXs). In the Pacific region, more than 20 analogs of CTXs have been identified to date. Based on their skeletal structures, they are classified into CTX1B-type and CTX3C-type toxins. We have previously reported species-specific and regional-specific toxin profiles. In this study, the levels and profiles of CTXs in fish present in the tropical western Pacific regions were analyzed using the liquid chromatography–tandem mass spectrometry (LC–MS/MS) technique. Forty-two fish specimens, belonging to the categories of snappers, groupers, Spanish mackerel, and moray eel, were purchased from various places such as Fiji, the Philippines, Thailand, and Taiwan. Only the fish captured from Fijian coastal waters contained detectable amounts of CTXs. The toxin levels in the fish species found along the coastal regions of the Viti Levu Island, the main island in Fiji, and the toxin profiles were significantly different from those of the fish species present in other coastal regions. The toxin levels and profiles varied among the different fish samples collected from different coastal areas. Based on the toxin levels and toxin profiles, the coast was demarcated into three zones. In Zone-1, which covers the northern coast of the main island and the regions of the Malake Island and Korovau, CTXs in fish were below the detection level. In Zone-2, CTX3C-type toxins were present in low levels in the fish. CTX1B-type and CTX3C-type toxins co-occurred in the fish present in Zone-3. The toxin profiles may have reflected the variation in Gambierdiscus spp.

scholarly journals Histamine Level in Freshwater and Marine Fish Sold in Bulgarian Markets

2020 ◽  
Author(s):  
D. Bangieva ◽  
D. Stratev ◽  
T. Stoyanchev
Keyword(s):  
Marine Fish ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fish Farms ◽  
Histamine Concentration ◽  
Microbial Decomposition ◽  
Fish Samples ◽  
Low Levels ◽  
Processing And Storage ◽  
Seafood Processing ◽  
And Storage

Background: Histamine is an essential biogenic amine produced as a result of microbial decomposition of histidine during seafood processing and storage. The objective of this study was to evaluate histamine concentration in freshwater and marine fish marketed in Stara Zagora region, Bulgaria. Methods: Forty fish samples were purchased from local fish farms and retail stores in Stara Zagora, Bulgaria. Enzyme-Linked Immunosorbent Assay was used to determine histamine levels. The data were processed using GraphPad Software InStat 3. Results: Histamine was detected in 26 out of 40 (65%) samples, and none of them exceeded the regulatory limit of 200 mg/kg. The average histamine content in marine fish (6.965±3.187 mg/kg) was insignificantly (p>0.05) higher than that in freshwater fish (4.503±1.133 mg/kg). Conclusion: The results reveal low levels of histamine in freshwater and marine fish indicating their good quality. However, its presence in seafoods remains a major food safety problem that requires permanent regulation of histamine concentration in fish.  

Transcription factor GATA-4 is expressed in a sexually dimorphic pattern during mouse gonadal development and is a potent activator of the Mullerian inhibiting substance promoter

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2665-2675 ◽  
Author(s):  
R.S. Viger ◽  
C. Mertineit ◽  
J.M. Trasler ◽  
M. Nemer
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Sexual Dimorphism ◽  
Sex Differentiation ◽  
Primordial Germ Cells ◽  
Gonadal Development ◽  
Downstream Target ◽  
Müllerian Inhibiting Substance ◽  
Coordinated Expression ◽  
Mullerian Inhibiting Substance

Mammalian gonadal development and sexual differentiation are complex processes that require the coordinated expression of a specific set of genes in a strict spatiotemporal manner. Although some of these genes have been identified, the molecular pathways, including transcription factors, that are critical for the early events of lineage commitment and sexual dimorphism, remain poorly understood. GATA-4, a member of the GATA family of transcription factors, is present in the gonads and may be a regulator of gonadal gene expression. We have analyzed the ontogeny of gonadal GATA-4 expression by immunohistochemistry. GATA-4 protein was detected as early as embryonic day 11.5 in the primitive gonads of both XX and XY mouse embryos. In both sexes, GATA-4 specifically marked the developing somatic cell lineages (Sertoli in testis and granulosa in ovary) but not primordial germ cells. Interestingly, abundant GATA-4 expression was maintained in Sertoli cells throughout embryonic development but was markedly down-regulated shortly after the histological differentiation of the ovary on embryonic day 13.5. This pattern of expression suggested that GATA-4 might be involved in early gonadal development and possibly sexual dimorphism. Consistent with this hypothesis, we found that the Mullerian inhibiting substance promoter which harbors a conserved GATA element is a downstream target for GATA-4. Thus, transcription factor GATA-4 may be a new factor in the cascade of regulators that control gonadal development and sex differentiation in mammals.

Variations of estradiol-17β and testosterone levels correlated with gametogenesis in the gonad of Zhikong scallop (Chlamys farreri) during annual reproductive cycle

2014 ◽  
Vol 92 (3) ◽  
pp. 195-204 ◽  
Author(s):  
J. Liu ◽  
Z. Zhang ◽  
L. Zhang ◽  
X. Liu ◽  
D. Yang ◽  
...  
Keyword(s):  
Reproductive Cycle ◽  
Sex Differentiation ◽  
Chlamys Farreri ◽  
Enzyme Linked Immunosorbent Assay ◽  
Annual Reproductive Cycle ◽  
Zhikong Scallop ◽  
The Mean ◽  
Highly Correlated ◽  
Reproductive Processes ◽  
Estradiol 17Β

To assess the potential roles of sex steroids in modulating reproductive processes in the Zhikong scallop (Chlamys farreri (Jones and Preston, 1904)), variations in estradiol-17β (E2) and testosterone (T) levels in gonads were examined monthly from January to December 2012 by enzyme-linked immunosorbent assay (ELISA). The mean concentrations of E2 and T in gonads ranged from 75.07 to 666.24 pg/g and from 91.09 to 506.28 pg/g, respectively. Concentrations of E2 were significantly higher in ovaries than in testes, while T concentrations were higher in testes than in ovaries during gametogenesis. Concentrations of E2 in females and T in males increased with development and maturation of gonad, attained the highest value before spawning, and decreased rapidly after spawning. A positive correlation between E2 levels and oocyte diameters (r = 0.743, P < 0.05, n = 25) was observed, suggesting that E2 may play a role in oogenesis. These findings indicate that E2 and T, which are highly correlated with the reproductive cycle, may play an important role in sex determination, sex differentiation, gametogenesis, and spawning in C. farreri.

scholarly journals Genes in the Azoospermia Factor A Region of the Y Chromosome Show Sexual Dimorphism in Rat Brain Prior to Gonadal Sex Differentiation

2021 ◽  
Author(s):  
Ajay Pradhan ◽  
Subrata Pramanik ◽  
Per-Erik Olsson
Keyword(s):  
Rat Brain ◽  
Steroid Hormones ◽  
Y Chromosome ◽  
Early Development ◽  
Sex Differentiation ◽  
Pcr Analysis ◽  
Female Rat ◽  
Male And Female ◽  
Time Points ◽  
Azoospermia Factor

Abstract BackgroundThe classical concept of brain sex differentiation suggests that steroid hormones released from the gonads program male and female brains differently. However, several studies indicate that steroid hormones are not the only determinant of brain sex differentiation and that genetic differences could also be involved.MethodsIn this study, we have performed RNA sequencing of rat brains at embryonic days 12 (E12), E13, and E14. The aim was to identify differentially expressed genes between male and female rat brains during early development. ResultsAnalysis of genes expressed with the highest sex differences showed that Xist was highly expressed in females having XX genotype with an increasing ratio over time. Analysis of genes expressed with the highest male expression identified three main genes. At E12, two genes located in the azoospermia factor A (AZFa) region on the Y chromosome were highly expressed in males. These were Ddx3y (1552-fold higher in males) and Kdm6c (147-fold higher in males). The expression of Kdm6c, but not Ddx3y, remained high at both E13 and E14. In qRT-PCR analysis, these two genes were highly expressed in all the stages in male brain. In addition to these genes, one of the several copies of Sry in the rat genome, Sry4, showed a high expression in the male brains at all three time points. At all three time points several other genes were also found to show sex bias, but with lower differences in gene expression. ConclusionThe observed sex-specific expression of genes at early development suggests that the rat brain is sexually dimorphic prior to gonadal action on the brain and identifies the AZFa region genes as a possible contributor to male brain development.

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