Reproductive strategy of the Australian Sharpnose Shark, Rhizoprionodon taylori (Elasmobranchii: Carcharhinidae), from Cleveland Bay, Northern Queensland

1992 ◽  
Vol 43 (1) ◽  
pp. 67 ◽  
Author(s):  
CA Simpfendorfer
Keyword(s):  
Litter Size ◽  
Reproductive Strategy ◽  
Life Histories ◽  
Early Embryo ◽  
Northern Territory ◽  
Embryonic Diapause ◽  
Early Embryo Development ◽  
Males And Females ◽  
Developmental Traits ◽  
Size At Birth

Reproduction and early embryo development of Rhizoprionodon taylori from Cleveland Bay, Queensland, was studied on the basis of 455 specimens caught between May 1987 and February 1990. Males and females mature at sizes larger than those reported from northern Western Australia, the Northern Territory and far northern Queensland. Mating occurs annually in summer, and the gestation period is approximately 11.5 months. After development to a small blastodermic disc, the embryos enter a state of diapause that lasts approximately 7 months. R. taylori is the only species of shark that is known to have a period of embryonic diapause. The litter size ranges from 1 to 10 (mean 4.9, being markedly larger than that for other carcharhinid species of a similar size. The size at birth is 220- 260 mm. The reproductive and developmental traits are discussed in relation to the life histories of this species and other carcharhinids.

scholarly journals The Potential Role of As-sumo-1 in the Embryonic Diapause Process and Early Embryo Development of Artemia sinica

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e85343 ◽  
Author(s):  
Bing Chu ◽  
Feng Yao ◽  
Cheng Cheng ◽  
Yang Wu ◽  
Yanli Mei ◽  
...  
Keyword(s):  
Embryo Development ◽  
Potential Role ◽  
Early Embryo ◽  
Embryonic Diapause ◽  
Artemia Sinica ◽  
Early Embryo Development

Sexual differences in interyear survival and life-span of Richardson's ground squirrels

1989 ◽  
Vol 67 (7) ◽  
pp. 1827-1831 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Sex Ratio ◽  
Life Span ◽  
Older Adult ◽  
Litter Size ◽  
Ground Squirrels ◽  
Sexual Differences ◽  
Maximum Life Span ◽  
Southern Alberta ◽  
Males And Females ◽  
Size At Birth

Although equal numbers of males and females were weaned in a population of Richardson's ground squirrels studied in southern Alberta, interyear survival was lower for males than for females in each year of life. Consequently, the sex ratio was biased toward females in both the yearling and older adult cohorts (overall ≤ 23 males per 100 females), and maximum life-span of males was 4 years, whereas that of females was 6 years. Compared with several other species of Spermophilus, Richardson's ground squirrels have a larger litter size at birth and a shorter life-span.

scholarly journals Crossbreeding and consanguinity management in pig farms in the departments of Ouémé and Plateau in Benin

2019 ◽  
Vol 12 (11) ◽  
pp. 1816-1825
Author(s):  
Ignace Ogoudanan Dotché ◽  
Simon Idohou ◽  
Mahamadou Dahouda ◽  
Pascal Kiki ◽  
Benoit Govoeyi ◽  
...  
Keyword(s):  
Litter Size ◽  
Slow Growth ◽  
Education Level ◽  
Male And Female ◽  
Genetic Types ◽  
Married Men ◽  
Pig Farms ◽  
Males And Females ◽  
Weaning Piglets ◽  
Size At Birth

Background: The improvement in pig zootechnical performances is a common practice in Benin. This improvement of the performances is made by the choice of the best reproducers in farms and the crossbreeding between the different breeds. Aim: This study aims to characterize practices related to consanguinity management in pigs reared in Ouémé and Plateau. Materials and Methods: Crossbreeding and consanguinity data were collected from 60 farms in these two departments. Frequencies and averages were calculated and compared between departments, genetic types, and origin of progenitors. Results: The majority of the investigated pig farmers in both departments were married men of primary or secondary education level. Most of them cross animals without a specific crossbreeding scheme. These crossings were performed to a greater extent (p<0.05) in Ouémé (94.28%) than in Plateau (52%). In general, farmers cross improved animals of high breeding values with the crossbred ones. These crossings were mainly performed to improve zootechnical performances. Renewing animals were commonly chosen from the farm or were provided from nearby farms. The majority of pig breeders in Ouémé (100%) and Plateau (86.67%) obtained reproductive animals from nearby farms. Males and females were sometimes bought from the same farm or from farms that pig breeders have sold reproductive animals in the previous years. In the case of selection within their own farm, male and female progenitors are separated at puberty by the majority of the breeders of Plateau (42.11%) and Ouémé (50%). Inbred mating was reported by breeders. More than half of breeders mate animals having a parental link in both departments. The mating was performed between animals of the same mother in 37.93% of farms in Ouémé and in 45.46% in Plateau. The main consanguinity consequences mentioned by the breeders were the high mortality at birth and weaning, piglets' weakness at the birth, the slow growth, and the decrease in litter size. Sows with at least one parent from external farm had a litter size at birth and weaning and a live-born piglets' number significantly higher than sows with both parents from the same farm. Conclusion: Rigorous monitoring of crossing and the filial links are necessary for pig farms for ensuring the improvement of zootechnical performances.

Minor Splicing Factors Zrsr1 and Zrsr2 Essential for Gametogenesis, Early Embryo Development and Conversion of Stem Cells into 2C-Like

2019 ◽  
Author(s):  
Isabel G&oacute;mez-Redondo ◽  
Priscila Ramos-Ibeas ◽  
Eva Pericuesta ◽  
Benjamín Planells ◽  
Raul Fernández-González ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryo Development ◽  
Early Embryo ◽  
Splicing Factors ◽  
Early Embryo Development

scholarly journals LIN28 coordinately promotes nucleolar/ribosomal functions and represses the 2C-like transcriptional program in pluripotent stem cells

2021 ◽  
Author(s):  
Zhen Sun ◽  
Hua Yu ◽  
Jing Zhao ◽  
Tianyu Tan ◽  
Hongru Pan ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryo Development ◽  
Pluripotent Stem Cells ◽  
Rna Binding ◽  
Stem Cell Differentiation ◽  
Early Embryo ◽  
Transcriptional Program ◽  
Cell Stage ◽  
Early Embryo Development ◽  
Nucleolar Stress

AbstractLIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28’s role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.

scholarly journals Geminin deletion in mouse oocytes results in impaired embryo development and reduced fertility

2016 ◽  
Vol 27 (5) ◽  
pp. 768-775 ◽  
Author(s):  
Xue-Shan Ma ◽  
Fei Lin ◽  
Zhong-Wei Wang ◽  
Meng-Wen Hu ◽  
Lin Huang ◽  
...  
Keyword(s):  
Embryo Development ◽  
Primordial Follicle ◽  
Early Embryo ◽  
Cell Cycle Checkpoint ◽  
Low Fertility ◽  
Early Embryo Development ◽  
Damage Repair ◽  
Cycle Checkpoint ◽  
Oocyte Meiotic Maturation ◽  
Zygote Stage

Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and early embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, early embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs early embryo development.

scholarly journals The Potential Roles of the G1LEA and G3LEA Proteins in Early Embryo Development and in Response to Low Temperature and High Salinity in Artemia sinica

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162272 ◽  
Author(s):  
Wei Zhao ◽  
Feng Yao ◽  
Mengchen Zhang ◽  
Ting Jing ◽  
Shuang Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Embryo Development ◽  
High Salinity ◽  
Early Embryo ◽  
Artemia Sinica ◽  
Early Embryo Development
Sign in / Sign up

Export Citation Format

Share Document