Different Stages Of Sexual Maturation Research Articles

Progranulin and Vaspin as Potential Novel Markers in the Etiology of Type 1 Diabetes in Children.

Background and Objectives: Diabetes is a significant health problem, prompting the search for new therapeutic strategies. Recently, researchers have focused on identifying novel markers for the progression of this condition. It is well established that adipokines, such as progranulin and vaspin, play crucial roles in regulating lipid and carbohydrate metabolism. Materials and Methods: This single-center cross-sectional study aimed to assess serum progranulin and vaspin levels in 80 children diagnosed with type 1 diabetes (T1D) and to examine their correlation with body mass index (BMI), glycated hemoglobin, and lipid profile. The cohort included 40 children newly diagnosed with diabetes, 40 children with long-term diabetes (20 well-controlled and 20 poorly controlled), and 14 non-diabetic children as a control group. Progranulin and vaspin levels were determined using a sandwich enzyme-linked immunosorbent assay. Results: There were no significant differences in the progranulin and vaspin concentrations in the studied groups (p = 0.246 and p = 0.095, respectively). No statistically significant differences were noted in the levels of both adipokines among boys and girls within the T1D, well-controlled T1D, and poorly controlled T1D groups. We did not find any differences in the progranulin and vaspin levels among all children with T1D and healthy controls when divided based on BMI percentiles. A negative correlation was observed between progranulin concentration and the age of children in the T1D, well-controlled T1D, and healthy groups. Furthermore, progranulin correlated negatively with BMI among children with T1D. In contrast, vaspin concentration correlated positively with age among healthy children. Conclusions: Our study provides novel insights into the status of progranulin and vaspin among pediatric participants with varying levels of type 1 diabetes control. However, further research involving larger patient cohorts and different stages of sexual maturation is warranted.

Dietary supplementation with ginseng extract enhances testicular function, semen preservation, and fertility rate of mature and aging Thai native roosters

The decrease in fertility in aging roosters is related to the reduced quality of ejaculated sperm. This study aimed to investigate the effect of dietary supplementation with ginseng extract at various concentrations (0–150 mg/kg) on testicular function, semen preservation, and fertility at different stages of sexual maturity (mature and aging roosters) in Thai native roosters. Pradu Hang Dum roosters at 32 (mature; n=24) and 75 (aging; n=24) weeks of age were fed diets with non-supplemented or supplemented ginseng extracts (50, 100, and 150 mg/kg) until the end of the experiment. In experiment 1, fresh semen samples were examined for the quality parameters of semen volume, sperm concentration, sperm motility, sperm viability, lipid peroxidation, and enzymatic activities. In experiment 2, semen was preserved at 5 °C for up to 48 h, and the semen quality and fertility potential were determined. In experiment 3, testicular function and testosterone concentrations were evaluated. The results showed that ginseng extract supplementation in the diets of both mature and aging roosters at 50 and 100 mg/kg improved fresh semen quality (P<0.05). A decrease in malondialdehyde levels in fresh semen was observed with increasing enzyme activities. In mature roosters, the progressive motility of cold-stored semen and fertility rates were higher in the G50 and G100 groups compared to the control and G150 groups after 24 h of storage (P<0.05). In aging roosters, the highest significant differences in progressive motility, viability, and fertility rates were observed in the G50 and G100 groups at all storage times (P<0.01). These improvements might be attributed to good testicular function in spermatogenesis, as revealed by the results of histological examination and testosterone concentrations. However, higher doses of ginseng extract supplementation negatively affected sperm quality. In summary, the recommended dose of ginseng extract supplementation in diets is 50 mg/kg. Fertility results indicated that insemination with semen preserved for 24 h was satisfactory in both mature and aging roosters.

Effects of dopamine and melatonin treatment on the expression of the genes associated with artificially induced sexual maturation in Japanese eel, Anguilla japonica.

Japanese eel (Anguilla japonica) is a commercially important fish species in Asia. Understanding factors like photoperiod, temperature, and lunar cycles is crucial for successful aquaculture and managing its reproduction. Melatonin and dopamine (DA) are essential for regulating reproduction in vertebrates, including fish. This study investigated the effects of melatonin and DA on the reproductive system of mature male Japanese eels to better understand reproductive regulation in fish. To clarify the effects of these hormones on sexual maturation in eels, a critical stage in the reproductive process, sexual maturation was induced by injecting human chorionic gonadotropin, which stimulates the production of sex hormones. To check the effect of melatonin and DA on sexual maturation, DA, melatonin, and DA + domperidone were intraperitoneally injected into fish from each group (six per treatment) at a dose of 1 mg/kg body weight. The fish were then examined using quantitative RT-PCR by comparing the messenger RNA level of reproduction-related genes (gonadotropin releasing hormone 1; gnrh1, gonadotropin releasing hormone 2; gnrh2, follicle stimulating hormone; fshβ, luteinizing hormone; lhβ and DA receptor 2b; d2b), involved in the gonadotropic axis in eels, to those that received a control injection. The results indicate significant differences in the expression levels of gnrh1, gnrh2 and d2b in the brain and d2b, fshβ, lhβ in the pituitary at different stages of sexual maturation. Melatonin appears to enhance the production of sex gonadotropins, whereas DA inhibits them. These findings suggest an interaction between melatonin and DA in regulating reproduction in Japanese eels.

Biology of the Reproduction of Mugilidae Neochelon falcipinnis (Valenciennes, 1836) in the Protected Marine Area of Niamone-Kalounayes (Casamance Estuary)

The reproduction of Neochelon falcipinnis was studied in the Marine Protected Area (MPA) of Niamone-Kalounayes located in the Casamance estuary (Senegal) from July 2021 to June 2022. The results of this study are presented after twelve (12) months of experimental seine fishing. Reproductive parameters such as length-weight relationship, condition factor (K), sex ratio (SR), gonadosomatic index (GSI) and size at first maturity (Lm50) were determined. A total of 386 individuals (150 males, 221 females and 15 of undetermined sex) were sampled. The sex ratio was in favour of females (0.68 or 1:1.47). The length-weight relationship showed a minor allometric growth with allometric coefficient b values of 2.70 for both sexes combined, 2.60 for males and 2.79 for females. The ANOVA test showed no significant difference in condition factor in males (P &gt; 0.05). In contrast, in females, there was a significant difference at the beginning of the cold season (P &lt; 0.05). The monthly change in gonadosomatic index associated with the different stages of sexual maturity indicated a breeding period in the dry season (May, June and July). Peaks of sexual maturity are observed in June for both sexes. Sizes at first sexual maturity were 18 cm for males and 19 cm for females. These results, obtained provide information on the reproduction of Neochelon falcipinnis that can help in decision-making for better management of the resource.

Cortisol differentially affects cell viability and reproduction-related gene expression in Atlantic cod pituitary cultures dependent on stage of sexual maturation

Through the action of cortisol, stress can affect reproductive biology with behavioural and physiological alterations. Using mixed sex primary pituitary cultures from Atlantic cod (Gadus morhua), the present study aimed to investigate potential direct effects of basal and stress level cortisol on the pituitary in terms of cell viability and reproduction-related gene expression at different stages of sexual maturity. Stress level of cortisol stimulated cell viability in cells derived from sexually maturing and mature fish. In cells from spent fish, high cortisol levels did not affect cell viability in terms of metabolic activity, but did stimulate viability in terms of membrane integrity. Basal cortisol levels did not affect cell viability. Ethanol, used as solvent for cortisol, decreased cell viability at all maturity stages, but did generally not affect gene expression. Genes investigated were fshb, lhb and two Gnrh receptors expressed in cod gonadotropes (gnrhr1b and gnrhr2a). Cortisol had dual effects on fshb expression; stimulating expression in cells from mature fish at stress dose, while inhibiting expression in cells from spent fish at both doses. In contrast, cortisol had no direct effect on lhb expression. While gnrhr2a transcript levels largely increased following cortisol treatment, gnrhr1b expression decreased in cells from spent fish and was unaffected at other maturity stages. These findings demonstrate that cortisol can act directly and differentially at the pituitary level in Atlantic cod and that factors facilitating these actions are dose-dependently activated and vary with level of sexual maturity.

Involvement of 11-ketotestosterone in hooknose formation in male pink salmon (Oncorhynchus gorbuscha) jaws

Mature male Pacific salmon (Oncorhynchus spp.) develop a hooknose, as a secondary male sexual characteristic, during the spawning period. It is likely that androgens regulate hooknose formation. However, endocrinological and histochemical details about the relationship between androgens and hooknose formation are poorly understood. In this study, we performed assays of serum androgens, detection of androgen receptor (AR) in hooknose tissues, external morphological measurement of hooknose-related lengths, and microscopic observation of hooknose tissues of pink salmon (O. gorbuscha) at different stages of sexual maturation. Expression of the arβ gene was detected in hooknose tissues of males but not females. The elongation of these tissues was mediated directly via androgens. Serum 11-ketotestosterone (11-KT) concentrations indicated a significant positive correlation with both jaw lengths during sexual maturation of males. In the upper jaw, cartilage tissue developed during hooknose formation, and AR-immunoreactive chondrocytes were located in the rostal-vetral regions of hooknose cartilage in maturing male. The chondrocytes in maturing males before entering into rivers exhibited rich-cytoplasm with high cell activity than at other sexual development stages. On the other hand, in the lower jaw, the development of the spongiosa-like bone meshworks. AR-immunoreactivity was detected in a proportion of the osteocytes and osteoblast-like cells in the spongiosa-like bone meshworks. These results indicate that hooknose formation in pink salmon, which is associated with the buildup of a structure with sufficient strength that it can be used to attack other males on the spawning ground, is regulated by 11-KT.

Identification and verification of potential piRNAs from domesticated yak testis.

PIWI-interacting RNAs (piRNA) are small non-coding RNA molecules expressed in animal germ cells that interact with PIWI family proteins to form RNA–protein complexes involved in epigenetic and post-transcriptional gene silencing of retrotransposons and other genetic elements in germ line cells, including reproductive stem cell self-sustainment, differentiation, meiosis and spermatogenesis. In the present study, we performed high-throughput sequencing of piRNAs in testis samples from yaks in different stages of sexual maturity. Deep sequencing of the small RNAs (18–40 nt in length) yielded 4,900,538 unique reads from a total of 53,035,635 reads. We identified yak small RNAs (18–30 nt) and performed functional characterization. Yak small RNAs showed a bimodal length distribution, with two peaks at 22 nt and >28 nt. More than 80% of the 3,106,033 putative piRNAs were mapped to 4637 piRNA-producing genomic clusters using RPKM. 6388 candidate piRNAs were identified from clean reads and the annotations were compared with the yak reference genome repeat region. Integrated network analysis suggested that some differentially expressed genes were involved in spermatogenesis through ECM–receptor interaction and PI3K-Akt signaling pathways. Our data provide novel insights into the molecular expression and regulation similarities and diversities in spermatogenesis and testicular development in yaks at different stages of sexual maturity.

A new record of Cottus spinulosus in the Talas River watershed Kazakhstan Central Asia

A population of Turkestan sculpin Cottus spinulosus Kessler, 1872 was discovered in the Talas River watershed in Kazakhstan in April 2012, and sampled in July and October 2013. The dorsal head and sides and back of all specimens were densely covered by small pricles which distinguishes this species from the Chatkal sculpin C. gobio jaxartensis Berg, 1916. The maximum age of examined fish was four years with a maximum total length of 84.2 mm. Stomach contents included larvae of Ephemeroptera, Trichoptera, Plecoptera, and Simuliidae; and Gammaridae, and Planariidae. Juveniles and individuals at different stages of sexual maturity were captured, indicating a reproducing population. The examined males ranged from maturity stage IV to V, and females from V to VI in October, egg diameter was 2–3 mm. The Turkestan sculpin is a repeat spawner in the Talas River watershed, as confirmed by morphological and analysis of ovaries. The Turkestan sculpin is a native species in freshwaters of Central Asia and is here reported as a new record in the Talas River watershed.

Systematic identification and characterization of miRNAs and piRNAs from porcine testes

microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) execute important regulatory roles in testis development and spermatogenesis, while previous studies mainly focus on the expression profiles in immature and mature porcine testes, which may cause a bottleneck for further understanding their complex physiological processes in porcine testes development and spermatogenesis. Thus, we presented the expression and characterization of miRNAs and piRNAs in DS (60-day-old), DN (90-day-old), DT (120-day-old) and DF (150-day-old) pig testes. In total, 12,834,628, 13,359,726, 12,851,249 and 12,938,601 clean reads were generated from these libraries, respectively. 293 mature and 36 novel miRNAs as well as 4923 piRNA clusters were identified from pig testes, and they showed an age-dependent manner. GO enrichment analysis of miRNA target genes and piRNA generated genes showed that they participated widely in regulating the pig spermatogenesis process. In addition, 12 differentially expressed miRNAs were randomly selected to validate using qRT-PCR. Our results provided novel comprehensive expression profiles of miRNAs and piRNAs in pig testes at different stages of sexual maturity, which will promote our knowledge of them in regulating the pig testes development and spermatogenesis process.

Imidacloprid induces various toxicological effects related to the expression of 3β-HSD, NR5A1, and OGG1 genes in mature and immature rats

This study aimed to evaluate the adverse effects of the insecticide imidacloprid (IMI) on male spermatogenesis, steroidogenesis, and DNA damage in sexually mature and immature rats. Forty male rats (mature and immature) were equally divided into four groups: two mature and two immature groups. IMI groups of both ages were orally administered IMI in corn oil at a concentration of 1 mg/mL for kg BW/day, whereas their respective controls were orally administered corn oil only (1 mL/kg of body weight) daily for 65 days. On day 66, the rats were lightly anesthetized and then euthanized by cervical dislocation. Whole blood was collected for hemogram, serum for hormonal profile, semen for sperm profile, and testes for gene expression and histopathological, and immunohistochemical examinations. The obtained results revealed that both sexually mature and immature rats orally exposed to IMI showed serious abnormalities in sperm morphology and concentrations, with an imbalance of sexual hormones. There were increases in the level of serum 8-hydroxy-2′-deoxyguanosine and in the percentage of comet (tailed) sperm DNA in the IMI-treated groups. The results exhibited the upregulation of a DNA damage tolerance gene (8-oxoguanine glycosylase 1) and downregulation of the activity of steroidogenic genes (nuclear receptor subfamily 5, group A, member 1 and 3β-hydroxysteroid dehydrogenase). Immunohistochemical examination of the B-cell lymphoma 2-associated X apoptotic protein in testicular sections showed various degrees of apoptosis in the spermatogonial cells of the IMI-treated rats compared to the control groups. These damaging effects of IMI were more pronounced in the sexually mature rats than in the immature rats. In conclusion, despite using a low dose of IMI in the present study, there were noticeable harmful consequences on the reproductive system at different stages of sexual maturity in male rats.

Genome-wide differential expression of genes and small RNAs in testis of two different porcine breeds and at two different ages.

Some documented evidences proved small RNAs (sRNA) and targeted genes are involved in mammalian testicular development and spermatogenesis. However, the detailed molecular regulation mechanisms of them remain largely unknown so far. In this study, we obtained a total of 10,716 mRNAs, 67 miRNAs and 16,953 piRNAs which were differentially expressed between LC and LW pig breeds or between the two sexual maturity stages. Of which, we identified 16 miRNAs and 28 targeted genes possibly related to spermatogenesis; 14 miRNA and 18 targeted genes probably associated with cell adhesion related testis development. We also annotated 579 piRNAs which could potentially regulate cell death, nucleosome organization and other basic biology process, which implied that those piRNAs might be involved in sexual maturation difference. The integrated network analysis results suggested that some differentially expressed genes were involved in spermatogenesis through the ECM–receptor interaction, focal adhesion, Wnt and PI3K–Akt signaling pathways, some particular miRNAs have the negative regulation roles and some special piRNAs have the positive and negative regulation roles in testicular development. Our data provide novel insights into the molecular expression and regulation similarities and diversities of spermatogenesis and testicular development in different pig breeds at different stages of sexual maturity.

Sex steroid level and sexual dimorphism expression of genes in gonads of the great sturgeonHuso husoLinneaus, 1758 during maturity developmental stages

Little is known about molecular mechanisms involved in gonad differentiation in sturgeon species. In non-mammalian vertebrates, sox9, dmrt1, cyp17a1 and ar are male specific genes in testicular differentiation and are highly conserved. In order to understand the mechanism underlying testicular development in sturgeon, we investigated sex steroids level of 11-ketotestosterone (KT) and testosterone (T) and relative expression of sox9, dmrt1, cyp17a1 and ar in great sturgeon gonads during different stages of sexual maturity. The results showed all studied genes had dimorphic patterns in males. In immature gonads (stage I), only cyp17a1 expressed in male gonads, while other genes did not express, and KT and T levels were low. Dmrt1 showed dimorphic expression pattern in male gonads at maturity stage II, III and IV. Furthermore, sox9 and ar mRNA presented significant dimorphic expression pattern in male gonads only at maturity stage 4. Plasma androgens levels were significantly higher in males compared to females during maturity stages II, III and IV. The results showed that among these four genes, only cyp17a1 expressed in male gonads at maturity stage I (immature), suggesting that this gene may be applicable as a sex marker in recently differentiated male great sturgeon. Sexually dimorphic patterns in other studied genes (sox9, dmrt1 and ar) suggesting that these genes may be important for testicular development and differentiation in premature great sturgeon. The obtained results provide a foundation for further research on sex differentiation and developing strategies for the sexing of sturgeon for aquaculture.

MicroRNAs Are Involved in the Regulation of Ovary Development in the Pathogenic Blood Fluke Schistosoma japonicum.

Schistosomes, blood flukes, are an important global public health concern. Paired adult female schistosomes produce large numbers of eggs that are primarily responsible for the disease pathology and critical for dissemination. Consequently, understanding schistosome sexual maturation and egg production may open novel perspectives for intervening with these processes to prevent clinical symptoms and to interrupt the life-cycle of these blood-flukes. microRNAs (miRNAs) are key regulators of many biological processes including development, cell proliferation, metabolism, and signal transduction. Here, we report on the identification of Schistosoma japonicum miRNAs using small RNA deep sequencing in the key stages of male-female pairing, gametogenesis, and egg production. We identified 38 miRNAs, including 10 previously unknown miRNAs. Eighteen of the miRNAs were differentially expressed between male and female schistosomes and during different stages of sexual maturation. We identified 30 potential target genes for 16 of the S. japonicum miRNAs using antibody-based pull-down assays and bioinformatic analyses. We further validated some of these target genes using either in vitro luciferase assays or in vivo miRNA suppression experiments. Notably, suppression of the female enriched miRNAs bantam and miR-31 led to morphological alteration of ovaries in female schistosomes. These findings uncover key roles for specific miRNAs in schistosome sexual maturation and egg production.

Aptidão física de escolares do sudoeste da Amazônia Ocidental em diferentes estágios de maturação sexual

Resumo O objetivo desta pesquisa foi comparar as variáveis antropométricas e de aptidão física de crianças e adolescentes de ambos os sexos em diferentes estágios de maturação sexual. Foram coletadas amostras de 436 escolares de Porto Velho, RO, 218 meninos e 218 meninas. Foi utilizado o protocolo de Tanner para dividir a amostra em relação aos estágios de 1 a 4 e na sequência foram coletados os dados de antropometria (peso, altura e IMC) e aptidão física (flexibilidade, força e corrida/caminhada). Este estudo caracterizou-se como "ex-post-facto", portanto, utilizou-se a média e desvio padrão, seguido de análise de variância (Anova "one-way") com "post-hoc" de Bonferroni, adotando um nível de significância de 5%. Não foram encontradas diferenças nas variáveis antropométricas para os dois sexos. Nos testes de aptidão física foram encontradas diferenças relativas à flexibilidade e corrida/caminhada no sexo feminino e nas variáveis força e corrida/caminhada no sexo masculino.

Força de preensão manual como preditor de aptidão física em crianças e adolescentes

The objective of this study was to examine the association between hangrip strength and physical fitness in children and adolescents at different stages of sexual maturation. We measured body composition and handgrip strength in 233 children and adolescents (10 - 17 years-old), who varied in terms of pubertal status. The subjects also performed the vertical jump test, standing long jump and sit-ups, as well as tests of flexibility, agility and speed. The level of energy expenditure was assessed with the international physical activity questionnaire. Handgrip strength differed by pubertal status, regardless of gender, whereas other parameters of physical fitness differed by gender and in the sample as a whole. Handgrip strength was consistently and independently associated with all other physical fitness variables, regardless of gender; some of those were mediated by energy expenditure (i.e., speed in seconds and in meters per second for the sample as a whole). The strength of the association between handgrip strength and physical fitness ranged from 20% (vertical jump test: R2=.20; P=.001) to 47% (speed in meters per second: R2=.47; P=.001). Our results support the idea that handgrip strength is consistently associated with several distinct parameters of physical fitness, regardless of age, gender or sexual maturation, suggesting that handgrip strength could be a highly accurate, independent predictor of physical fitness

Avaliação da maturação em crianças e jovens

Maturation assessment is an important issue within sports practice by children and adolescents. In the first two decades of life, children and adolescents experience three interactive processes: growth, maturation and development. The first process refers to physical size and proportions; the second refers to skeletal, reproductive, somatic, neuroendocrine and neuromuscular functions; the third refers to cognitive, emotional, social, motor and moral issues. This text aimed to review the methods to assess the maturation of children and adolescents, describing their main characteristics, advantages and disadvantages. The maturation of the various organ systems occurs at different rates and times, leading us to conclude that the assessment of the state of biological maturity varies within the body system taken into consideration. The efficiency of a given strategy is directly linked to its ability to identify the different stages of sexual maturation. Systems most commonly used for evaluation of maturation are reproductive (sex) and somatic. Dental maturation (calcification and eruptions) is occasionally used, but tends to behave independently of the other three systems. Hormonal maturation influences all these aspects and should also be considered. However, skeletal maturity (bone age) seems to gather more advantages in determining the maturational stage of youth compared to the others, even if they are in peripuberal period.

Expression of 11β‐Hydroxysteroid Dehydrogenase Type 1 and Glucocorticoid Receptors in Reproductive Tissue of Male Horses at Different Stages of Sexual Maturity

Glucocorticoids (GCs) as mediators of the stress response may affect Leydig cell function by inhibiting either luteinizing hormone receptor expression or testosterone biosynthesis. The isozymes 11β-hydroxysteroid dehydrogenase (11βHSD) 1 and 11βHSD2 control the intracellular cortisol levels. Little is known about the effects of stress on fertility in the equine. The objective of the present study was to determine the presence and cellular localization of glucocorticoid receptors (GCR) and glucocorticoid-metabolizing enzymes (11βHSD1 and 11βHSD2) in equine epididymal and testicular tissue with special regard to sexual maturation. Testicular and epididymal tissue was collected from 21 healthy stallions, and four age groups were designed: pre-pubertal, young, mature and older horses. Immunohistochemistry (IHC) analysis and quantitative real-time PCR (qRT-PCR) were used. Pre-pubertal horses showed higher testicular gene expression of 11βHSD1, 11βHSD2 and GCR than horses of all other groups (p < 0.05). A positive intranuclear immunoreaction for GCR was seen in epithelial cells of caput, corpus and cauda epididymidis and in Leydig cells. Significant differences (p < 0.05) between age groups occurred. The number of Leydig cells staining positive for GCR was highest in immature stallions (p < 0.05). The enzyme 11βHSD1 was localized in epithelial cells of the caput and corpus epididymidis and in Leydig cells. As determined by enzyme assay, nicotinamide adenine dinucleotide (NAD)-dependant dehydrogenase (oxidation) activity was not detected in testicular tissue from immature stallions but in all other age groups (n = 3 per group). Results of this study suggest a contribution of GCs to maturation of male reproductive tissue in horses. In mature stallions, expression of 11βHSD enzymes and the oxidative 11βHSD activity in Leydig cells and epididymal basal and principal cells suggest a protective role on these tissues contributing to physiological intracellular glucocorticoid concentrations.

Reproductive biology of Lychnorhiza lucerna (Cnidaria: Scyphozoa: Rhizostomeae): Individual traits related to sexual reproduction

We studied individual traits related to the sexual reproduction of Lychnorhiza lucerna and reviewed earlier studies of sexual maturation in scyphomedusae, focusing on non-brooding species. Lychnorhiza lucerna is a gonochoric species and sexual dimorphism was noted in the gonadal colour. There were no brooding structures or any other distinguishable features enabling macroscopic determination of sex. Gametogenesis resembled descriptions available for other rhizostomes and semaeostomes. Both processes are asynchronous, with gametes at all stages of development occurring together. Oocytes arose from the gastrodermis and maintained contact with it via trophocytes throughout vitellogenesis. Spermatogenesis occurred within spermatic follicles arising from nested primary spermatogonia. Population features of sexual reproduction were defined by characterizing and quantifying individuals at different stages of sexual maturity. In Scyphozoa, sexually mature medusae can be detected by (1) the presence of fully developed gametes in the gonads indicating incipient spawning, or (2) the presence of spent follicles as evidence of ongoing or recent spawning. Whereas the former allows more detailed study of sexual reproductive patterns of any species, the latter constitutes an option for non-brooders (as in L. lucerna) equivalent to the search of fertilized eggs or planulae for brooder species.

Morphological Aspects of Spermatogenic Cells at Different Stages of Sexual Maturation in Black Isogenic C57BL/6/Uni Mice

Morphological Aspects of Spermatogenic Cells at Different Stages of Sexual Maturation in Black Isogenic C57BL/6/Uni Mice

Production of Transgenic Mice by Type-A Spermatogonia-Mediated Gene Transfer

Abstract Type-A spermatogonia first appear at between 3-7 d postnatally in mice and are the only immortalized diploid cells that reproduce in adulthood in these animals. In our current study, we explored the feasibility of producing stable transgenic mice using these cells. Enhanced pEGFP-N1 plasmids were suspended in ExGen500 transfection reagent and injected at different angles into the testes of 7-d-old male ICR mice. The resulting type-A spermatogonia-mediated gene transfer (TASMGT) mice were then mated with normal females at different stages of sexual maturity (6, 12, and 24 wk). The integration and expression of the introduced EGFP gene was evaluated in the F 1 transgenic offspring by PCR and Southern blotting analysis. The foreign gene integration rates for a low-dose group (15 μL gene suspension injected into each testis) and a high-dose group (30 μL suspensions injected) at the three stages of female sexual maturity tested were 11.76% (2/17), 14.29% (3/21), and 11.11% (2/18), and 5% (1/20), 5.56% (1/18), and 0 (0/17), respectively. The average integration rates for these two dose groups were 12.5% (7/56) and 3.64% (2/55), respectively, which was a significant difference ( P<0.05). Semi-quantitative RT-PCR analysis further showed that the introduced GFP gene was expressed in 3/9 integration mice. In addition, GFP expression was observed in the sperm cells from the TASMGT mice, and also in the embryos and F 2 pups from the F 1 generation transgenic mice. Hence, although the foreign gene integration rate for TASMGT is not high and the transgenic offspring show as yet unexplained defects, our results indicate that this method is a potentially feasible and reproducible new approach to creating transgenic mice.