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At least 19 recordsLinked to original sources
PubMed1978

[Reproductive lifespan and reproductive performance in SPF C3H mice: the onset of reproductive life and production efficiency (author's transl)].

To improve the production system, the onset and the termination of reproductive life of C3Hf/HeMsNrs mice mated immediately after weaning and reared for 400 days of life, were studied. From weaning females mated with a full grown male (group A), the first litter was obtained at a mean age of 47 days, suggesting the first copulation at 26 days of age. The age of males at the first copulation was estimated to be at 44 days of age from the age giving the first litters in weanling males mated with weanling (group B) and full grown (group C) females. The sex ratio of litters delivered by young dams tended to be excess in males. The reproductive performance of dams in later life was not affected by the parturition in earlier age. The production efficiency with weaned youngs per pair during the first 200 days after mating was the highest in group A. It was found from these results that the C3H females attained their sexual maturity at 5 to 6 days after weaning, being available for breeding without any deletion in reproductive performance.

Age Factors↗
PubMed1979

Reproduction study of carteolol hydrochloride in mice. Part I. Fertility and reproductive performance.

Carteolol was administered orally by gastric intubation at 3, 15, 75 or 150 mg/kg/day to ICR-JCL mice of both sexes prior to mating and to females during early stage of pregnancy to determine its effects on the entire reproductive process and fetal development. Following results were obtained: 1) The decrease of spontaneous motor activity was observed in all treatment groups, and some animals in the 75 mg/kg and 150 mg/kg groups pressed the chest or abdomen against the cage wall. 2) The incidence of early resorptions in the 75 mg/kg and 150 mg/kg groups was significantly higher than that in controls.3) The ossification of the talus and calcaneus was significantly retarded in the 75 mg/kg and 150 mg/kg groups. The maximum non-effective dose on fertility and reproduction for carteolol was estimated to be 15 mg/kg/day, although the incidence of early resorptions was slightly elevated with this dose.

Animals↗
PubMed1978

Evidence of a uteroglobin-like protein in epithelial cells of reproductive and non-reproductive tissues of the rabbit.

An antiserum raised in a goat to a uteroglobin-like protein isolated from uterine fluid of oestrous rabbits was used in an immune fluorescence test to localize an antigen present in the reproductive tract of oestrous and pseudopregnant rabbits and mammary gland tissue. The antigen was also present in the vas deferens and seminal vesicle, but not in testis. Non-reproductive tissues, such as lung, small intestine, bladder and thyroid showed specific fluorescent staining which was eliminated or significantly reduced by absorption of the antiserum with a purified uteroglobin preparation.

Animals↗
PubMed1979

Reproductive performance of Iraqi buffaloes. I. Pattern of female reproduction.

In a buffalo herd at Amara Buffalo Breeding Station between October 1975 and October 1976 various features were investigated of the reproductive performance of heifers. The average age of the heifers was 22.01 at first estrus, 22.50 at ovulation, 26.05 at conception, and 38.8 months at calving. Estrus occurred at an average interval of 72.7 days after calving. Extended post-partum anestrus for more than 90 days was observed in 26.8% of the animals studied. The average length of the calving interval was calculated as 408 days. 67.3% of the calvings took palce between June and October.

Animals↗
PubMed1978

[Reproduction and sexuality of parasitic copepods of fishes. I. The reproductive apparatus of Chondracanthus angustatus Heller, 1865: anatomy, histology, and spermiogenesis (author's transl)].

The pygmy males of Chondracanthus angustatus are fixed on the genital segment of the female on two anterior-ventral tubercules. The genital system is formed by two dorsal testes, two broad vas deferens and two seminal vesicles each one containing a spermatophore. Two types of cells can be seen in the interstitial tram: the sexual (normal and abortive) and the somatic ones. The plasmic and nuclear membranes joined together on one end of the spermatid; on the opposite pole, the mitochondria penetrate into the cytoplasmic expansions. The non-motile starfish spermatozoa present neither di-ferentiated acrosome nor centrioles. The male gametes are stocked in the spermatophore and enveloped by many kinds of secretions. Spermatozoa are discharged into the female integument folds and they reach the seminal receptacle with the help of the villosities movement; they stay there till fertilization occurs.

Animals↗
PubMed1975

Reproduction of the normal sexual cycle and reproductive ability in castrated guinea pigs by implantation of the ovary by a new method.

Hormonal and generative activity of the "free" ovarian graft in the uterine wall was studied in 43 sexually mature guinea pigs. Ovaries were grafted by a personal method and by the method of Bland and Donovan. In the author's method, halves of the ovaries were implanted in the uterine wall in such a way that the graft communicated with the uterine cavity and received supplementary vascularization from the connective tissue of the parametrium. Morphologic and histochemical (PAS-positive substances) changes in the free ovarian grafts in the uterus were studied. Hormonal activity of grafts was assessed on the basis of vaginal smears. It was concluded that hormonal activity of the ovary engrafted in the uterine wall depends on the method of grafting. By the author's method, in which blood vessels from the parametrial connective tissue penetrate into the ovary, hormonal activity is the same as before operation and pregnancy is possible. In the method of Bland and Donovan, the sexual cycle and time of opening of the vagina are considerably shortened.

Animals↗
PubMed2025

Unisexual reproduction in the global human fungal pathogen Cryptococcus neoformans.

The human fungal pathogen Cryptococcus species complex (encompassing Cryptococcus neoformans, Cryptococcus deneoformans, and the Cryptococcus gattii species complexes) exhibits diversity in sexual reproduction, including α-a mating, pseudosexual reproduction, as well as unisexual reproduction initiated from a single isolate or between isolates of the same mating type. A central conundrum is that while most Cryptococcus natural populations exhibit significant α mating-type bias, genetic and genomic analyses show recombination occurs in nature. The discovery of unisexual reproduction in C. deneoformans provided insight; however, thus far, unisexual reproduction has never been directly observed in the predominant global pathogenic species C. neoformans. Here, we provide evidence that mutating the RIC8 gene, which encodes a conserved guanine nucleotide exchange factor (GEF) involved in both chaperoning and activating Gα proteins, enables unisexual reproduction in C. neoformans. Additionally, we show that genetic variation in the natural population promotes unisexual reproduction, and unisexual reproduction in C. neoformans involves canonical meiotic recombination. Finally, we found that deletion of both GPA2 and GPA3 in the MATα background leads to self-filamentation without sporulation, suggesting that differential modulation of the Gα proteins, likely involving Ric8, could underlie the switch between different modes of sexual reproduction in Cryptococcus. Our study further highlights that the highly conserved Ric8 GEF can act as an important regulator of cellular development in response to environmental stimuli and could modulate sexual reproduction in nature. We hypothesize that unisexual reproduction occurs much more frequently in nature than currently appreciated, and possibly in other fungi and microbial eukaryotes as well.

Cryptococcus neoformans↗