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The mammalian pineal gland has become firmly established as a neuroendocrine structure possessing the ability to influence the functions of the sex glands. There is substantial evidence in the literature that pineal factors also affect the activities of other endocrine systems. The pineal gland is thus conceivably far-reaching in its regulatory actions on physiological function, involving actions on the adrenal cortex, the thyroid, and parathyroid glands as well as the gonads of both sexes. The pineal gland of the hamster and the rat responds to environmental influences, particularly changes in length of the daily photoperiod, and in turn exerts regulatory effects on the activity of the testis. This relation is much more sensitive in the hamster where lack of adequate illumination stimulates pineal antigonadal activity to produce inhibition of both testicular gametogenesis and androgenesis. Involvement of the pineal in these responses to darkness or blinding has been clearly demonstrated by the negating effects of its removal. The physiological role of the pineal in regulating seasonal changes in testicular activity and reproductive capacity of the hamster has now been formulated (Reiter, 1973a, 1973b). The laboratory rat, a continuous breeder, is far less sensitive to lack of photic input. Surgical and environmental manipulations involving altered pineal activity invariably lead to less dramatic changes in various parameters of male reproductive function. The evidence would seem to indicate that pineal function in the rat is primarily related to the regulation of testicular endocrine function. Consequently, its physiological role may be associated with seasonal changes in libido in relation to environmental influences, by virtue of the action of pineal factors on androgen status. Spermatogenesis, on the other hand, was unaffected for periods as long as 1 year after the blinding of rats at the time of puberty (Kinson and Liu, 1974). There is evidence that the pineal gland has a part to play in the timing of puberty in the rat and in circadian variations in testosterone levels in the adult animal. Two groups of compounds have been identified as pineal agents and possibly pineal hormones. While the indoles have been more widely investigated as pineal antigonadal factors, the involvement of polypeptides in pineal actions was indicated a decade ago and these compounds are now receiving vigorous attention. Pineal factors influence testicular function by interaction with the neuroendocrine system to affect pituitary gonadotropin secretion. The higher neural centers appear to be responsive to indoles and via the releasing factors give rise to changes in pituitary content and circulating levels of FSH and LH. Prolactin also has been shown to respond to change in ambient lighting and to pinealectomy. Partially purified polypeptide fractions are now claimed to be considerably more potent antigonadotropically than melatonin, the indole most favored as a pineal hormone...
A number of reports suggest that the role of radiation-induced G2 arrest is to allow repair of potentially lethal damage in the cells before it comes to mitosis. Though the exact nature of the damage undergoing repair during the delayed G2 is not known, the yield of chromosomal aberrations observed in metaphase seems to be a good parameter to predict reproductive death of cells. In a previous paper, we have shown that poly-D-lysine, acting in a fashion reminiscent of that of caffeine in mammalian cells, is able to induce a premature onset of mitosis concomitant with an increase in the frequency of chromosomal aberrations in mutagen-treated plant cells. Cultured CHO cells were pre-exposed to either X-rays or mitomycin C and given different doses of the polycationic compound during G2 in order to analyze any effect on the frequency of chromatid-type aberrations as well as any modification of cell-cycle kinetics. A potentiation of chromosome damage and a premature arrival at mitosis were observed for both mutagens, though the effect was more evident in X-irradiated cells.
MOTIVATION: The classical duplication episode clustering (EC) model introduced by Guigó et al. in the 1990s provides a foundational approach for inferring genomic duplication events crucial to understanding genome evolution. This model clusters single gene duplications from a collection of gene trees at locations in the species tree to minimize the total number of such locations, called duplication episodes. However, it does not capture reticulate evolutionary histories. RESULTS: Here, we introduce NetEC, a novel extension of this problem to phylogenetic networks. To solve NetEC, we first develop a polynomial-time dynamic programming (DP) algorithm for testing whether a given set of network nodes can serve as episode locations. We then propose a main inference algorithm that utilizes this DP component to optimize the episode count; while the feasibility test runs in polynomial time, the full optimization has exponential worst-case complexity, and an optional heuristic mode is provided for larger instances. We also propose an extended episode analysis procedure that identifies additional genomic duplication candidates below reticulation nodes, complementing the main algorithm by resolving potential upward clustering of duplications induced by reticulation. We evaluate our method on simulated data and on an empirical Pandanales dataset comprising over 29 000 gene trees, demonstrating exact and accurate inference of genomic duplication events even in the presence of multiple reticulations. AVAILABILITY AND IMPLEMENTATION: All experiments were conducted using the NetEC tool (https://github.com/ppgorecki/netec), with all input data, scripts, and parameter settings for reproduction available in the same repository.
Piperonyl butoxide (PB) was administered continuously to mice from 5 weeks of age in the F0 generation to weaning of the F2 generation. PB was administered in the diet at levels of 0 (control), 0.1, 0.2, 0.4 and 0.8%. Selected reproductive, developmental and behavioural parameters were measured. Litter size and litter weight were reduced in higher-dosed groups, and the body weight of the pups in the lactation period was reduced in dosed pups in each generation. The survival index at postnatal day 21 of the group receiving 0.8% PB was reduced in each generation. The developmental and behavioural parameters in the lactation period were little different from those of the controls, apart from olfactory orientation in the F1 generation. However, in the F2 generation mice, surface righting, cliff avoidance and olfactory orientation were adversely affected in treatment groups. The results suggest that PB had adverse effects on reproductive, developmental and behavioural parameters of mice, with increasing effects in subsequent generations of offspring.
Two studies were conducted to observe the effects of an essential fatty acid (EFA) deficiency, added dietary corn oil and pair-feeding on growth, reproduction and other physiological parameters in the mature cockerel. A purified, linoleic acid (LA)-deficient diet (0.01% LA), or additions of 5% (3.01% LA) or 15% (9.04% LA) corn oil, were fed ad libitum from hatching through 24 weeks of age. Reductions in growth, feed consumption, and comb, and testes size, incomplete spermatogenesis, increased tissue eicosatrienoic acid (20: 3 omega 9) and changes in weights of selected internal organs were observed in deficient cockerels. Total pituitary gonadotropic activity was measured by two bioassay procedures and blood luteinizing hormone was measured by radioimmunoassay. By maturity both of these parameters were significantly reduced in deficient chickens. When these chickens were fed diets with 5% or 15% corn oil under pair-feeding or ad libitum conditions from 20 to 24 weeks, the reduced growth, comb and testes size and gonadotropin metabolism appeared to be caused by depressions in appetite and energy intake rather than EFA per se. The degenerate testicular histology of the 20-week old deficient cockerels, while responding fully to the ad libitum intake of the diets containing corn oil, showed only partial rehabilitation of spermatogenesis when diets with either 5% or 15% corn oil were pair-fed. In general, increasing the level of dietary fat from 5% to 15% did not cause many physiological changes.
In search of etiologic relevancy of the steroid deviations in urine, we compared the reproductive activities of patients having cervical cancer with those of normal controls. A premenopausal patient experienced the birth of her first child significantly earlier than did the urban control of corresponding age, despite their similarity of age at menarche. However, when the same patient was compared with the premenopausal rural control, this differences was not found. The same parameter also failed to differentiate a postmenopausal patient from the corresponding control of urban origin. The premenopausal patient who was indistinguishable from the rural control by age at first delivery was distinguished from the rural control by reduced excretions of adrenal steroids including 11-deoxy-17 ketosteroids and some corticosteroid metabolites. The spectrum and the degree of deviation of urinary steroids for a patient coincided with the spectrum and the degree of age dependency of the urinary steroids for a normal woman during and after adolescence. These findings indicated that the inability of the reproductive parameter to discriminate a patient was associated with growth retardation in a population, and a maturation deficiency of the adrenal gland (arrest of adrenarche) was implicated in the genesis of cervical cancer.
The study of time parameters of cell kinetics in the rats exposed to 34-day hypokinesia showed that changes in cell reproduction developed in rapidly and slowly renovating cells in a different way. The DNA synthesis and mitotic division were drastically inhibited in liver cells; the duration of the premitotic period of the mitotic cycle was significantly reduced in the cryptal epithelium of the small intestine. Hypokinesia did not cause important changes in the phasic structure of diurnal rhythms of cell division in the tissues tested and, consequently, did not lead to changes in the mechanisms of time organization of the cell reproduction system. It is concluded that the state of motor activity of animals is not the major time cue for cell division processes.
The photosynthetic activity of Chlorella vulgaris str. LARG-1 was studied after its dark exposure in the Tamiya medium to space flight factors enboard the Salyut orbital station. The exposure of Chlorella cells in the inactive state did not influence their basic physiological parameters (rate of growth and reproduction, cell size and population structure, chlorophyll content, cell viability) during subsequent intensive cultivation. These results show the possibility of storing the generative material of unicellular algae under the experimental conditions.
An investigation was done to determine whether patients with cancer of the cervix from Buffalo and Kenmore, New York, differed from a random sample of women from the same communities on a variety of parameters associated with marital and reproductive history. A comparison of the 285 patients and 1,620 controls showed that patients were more likely than controls to have been black and non-Jewish, to have married young, to have had more than one husband, and to have been young at the time of their first pregnancy. In addition, they were more likely to have frequently used the vaginal douche and to have used it over many years. As frequency of douche increased, so did risk of cervix cancer.
For the effects of voltages on health and reproduction, 40 cows in second to fifth lactation were divided into four groups of 10. These included a control group that was not subjected to voltages and three treatment groups that were given either 1, 2, or 4 V at the water bowl. Cows in the treatment groups were exposed during the entire lactation to voltage whenever they drank. Voltages did not sufficiently affect milk yield. General health parameters studied were mastitis, hoof problems, and changes in body weight. Reproductive and calving parameters examined were days to first breeding, days open, services per conception, response to PGF2 alpha, calving intervals, visible abortion, and calves born dead. Voltages did not significantly influence cow health or reproductive performance.
The reproductive success of cows directly influences the profitability of dairy farms. Reproductive traits, particularly calving-related traits, generally have low heritability but sufficient additive genetic variance to enable genetic progress through genomic selection. Thus, the primary objectives of this study were to estimate genetic parameters and perform single-step genome-wide association studies (ssGWAS) for calf size, calving ease, gestation length, and stillbirth in Holstein cattle. Variance components were estimated based on animal models and Bayesian inference using a data set containing 226,717 animals with phenotypic records, 15,761 animals genotyped with 45,101 SNP markers, and 461,819 animals in the pedigree. SNP effects were estimated using the single-step GBLUP method. For direct and maternal genetic effects, heritability estimates (posterior standard deviation) ranged from 0.001 (0.002) for gestation length in heifers to 0.16 (0.001) for gestation length in cows. Genetic correlations ranged from -0.57 (0.01) between calving ease and stillbirth in heifers to 0.74 (0.01) between gestation length evaluated in heifers and cows. The ssGWAS results supported a highly polygenic architecture for calving-related traits, with most genomic signals not reaching genome-wide significance. A genome-wide significant association was detected for calving ease in cows on BTA23, highlighting FARS2 as a positional candidate gene. The strongest GWAS signals for each trait harbored additional biologically important candidate genes, including NPPA, NPPB, BCHE, EPHA4, DLD, and GTF2I. Given the generally low heritability estimates and the predominantly polygenic architecture observed for these traits, genomic selection may contribute to the genetic improvement of calving-related traits in Holstein cattle, with potential benefits for cow welfare, calf survival, and overall dairy production efficiency.
The food and agriculture industry employs 14.6% of the female industrial work force in France. Workers are exposed to a variety of environmental and organizational constraints (eg, irregular schedules, cold, uncomfortable postures, repetitive movements). In 1987-1988 a medical examination and questionnaire were administered to 726 workers with menstrual periods in 17 poultry slaughterhouses and six canning factories. Anomalies (irregular cycles, amenorrhea, long cycles) during the previous year were associated with work conditions. After adjustment for relevant nonoccupational variables, irregular cycles were significantly related to schedule variability and cold exposure, amenorrhea was associated with cold exposure, and long cycles with schedule variability. Other parameters such as repetitive work, standing posture, lifting weights, job satisfaction, and hours of domestic work were not associated with cycle anomalies. Cycle anomalies may be a useful indicator of occupational effects on female reproduction, analogous to the use of sperm parameters to warn of effects on male workers.
In this study, the effects of nine different chemicals on the survival, growth, and reproduction of the earthworm species Eisenia andrei were determined using a recently developed method. Earthworms were exposed for 3 weeks to the test chemicals in an artificial soil substrate. Additional data on the acute toxicity of these chemicals were derived from the literature. For some chemicals, cocoon production was the most sensitive parameter (cadmium, chromium, paraquat, fentin, benomyl, phenmedipham), while for others cocoon hatchability was most sensitive (pentachlorophenol, parathion, carbendazim). In the case of parathion, growth of the worms seemed to be even more sensitive than reproduction. As an overall parameter for the effect on earthworm reproduction, the total number of juveniles produced per worm appeared to be a useful parameter. Differences between (acute) LC50 values and the lowest NOEC value for effects on growth and reproduction were different for each chemical. Difference was greatest for cadmium (a factor of greater than 100) and smallest for fentin, benomyl, and pentachlorophenol (a factor of 5-6).
Male fertility is primarily assessed using descriptive semen parameters, such as sperm concentration, motility and morphology. These conventional parameters provide an initial assessment of male reproductive health and may explain why a couple is struggling to conceive; however, they are not a direct measure of fertility potential. Growing evidence suggests that spermatozoa transmit far more than paternal DNA. Alongside the genome, spermatozoa deliver proteins, RNA and epigenetic information that are responsive to environmental and lifestyle exposures, and can influence embryo development, pregnancy outcomes and offspring health. This emerging concept challenges the view that male fertility is defined solely by successful conception. Here, we discuss evidence that spermatozoa act as carriers of environmental and lifestyle 'memories', transmitting molecular information shaped by paternal health to the next generation. We further consider the implications for assisted reproductive technologies, which select spermatozoa largely on their capacity to move while overlooking the molecular cargo they transmit. Recognising spermatozoa as vectors of environmental information reframes male fertility and highlights the need for biomarkers that assess molecular integrity alongside conventional clinical parameters.
A biologically motivated breast cancer incidence rate function was fit to data from a published case-control study conducted in countries whose incidence is high (Wales and the United States), moderate (Brazil, Greece, and Yugoslavia), and low (Japan and Taiwan). The data include personal characteristics of 3,925 breast cancer cases and 11,327 controls interviewed in selected hospitals in 1964-1968. Parameters in the function specify the dependence of age-specific breast cancer incidence rates on age at menarche, age at menopause, occurrence and timing of full-term pregnancies, and body mass. Parameters were estimated separately for high-, moderate-, and low-risk countries. Examination of residuals provided little evidence of inadequacy of the fitted function in describing combined effects of the characteristics studied. The following patterns were seen in all three risk groups: 1) Incidence rates jump to a higher level after first childbirth, but then increase with age more slowly thereafter. 2) Rates increase with age more slowly after menopause than before. 3) Rates change quadratically with body mass index among all women, although the main trend varies: Rates decrease with body mass among premenopausal women in high-risk countries, but increase with body mass in all other groups of women. Similarities of parameter estimates across countries suggest that reproductive events and body fat exert similar effects on all women, regardless of breast cancer rates in their country of residence.
The inactivation of aerosolized Escherichia coli by ozone, cyclohexene, and ozonized cyclohexene was studied. The parameters for damage were loss of reproduction and introduction of breaks in the deoxyribonucleic acid (DNA). Aerosolization of E. coli in clean air at 80 percent relative humidity or in air containing either ozone or cyclohexene hardly affected survival; however, some breaks per DNA molecule were induced, as shown by sucrose gradient sedimentation of the DNA. Aerosolization of E. coli in air containing ozonized cyclohexene at 80 percent relative humidity decreased the survival by a factor of 10(3) or more after 1 h of exposure and induced many breaks in the DNA.
Leslie's or Lotka's population model has a rate of natural increase (lambda or r) which represents the growth rate of the population and characterizes the ability of the population to attain a stable age distribution. In this article are presented upper and lower bounds on that rate, primarily in terms of the net reproduction rate and other commonly used parameters of the population. Also a discussion is given of quadratically convergent numerical iterative methods of computing the growth rate.