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Journal articles on the topic 'Reproductive phases'
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Chandra, Vikram, Ingrid Fetter-Pruneda, Peter R. Oxley, Amelia L. Ritger, Sean K. McKenzie, Romain Libbrecht, and Daniel J. C. Kronauer. "Social regulation of insulin signaling and the evolution of eusociality in ants." Science 361, no. 6400 (July 26, 2018): 398–402. http://dx.doi.org/10.1126/science.aar5723.
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Queens and workers of eusocial Hymenoptera are considered homologous to the reproductive and brood care phases of an ancestral subsocial life cycle. However, the molecular mechanisms underlying the evolution of reproductive division of labor remain obscure. Using a brain transcriptomics screen, we identified a single gene,insulin-like peptide 2(ilp2), which is always up-regulated in ant reproductives, likely because they are better nourished than their nonreproductive nestmates. In clonal raider ants (Ooceraea biroi), larval signals inhibit adult reproduction by suppressingilp2, thus producing a colony reproductive cycle reminiscent of ancestral subsociality. However, increasing ILP2 peptide levels overrides larval suppression, thereby breaking the colony cycle and inducing a stable division of labor. These findings suggest a simple model for the origin of ant eusociality via nutritionally determined reproductive asymmetries potentially amplified by larval signals.
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BARBO, DOROTHY M. "Reproductive Health Over the Life Phases: An Overview." Clinical Obstetrics and Gynecology 45, no. 4 (December 2002): 1181–88. http://dx.doi.org/10.1097/00003081-200212000-00024.
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Zadrag-Tecza, Renata, Magdalena Kwolek-Mirek, Małgorzata Alabrudzińska, and Adrianna Skoneczna. "Cell Size Influences the Reproductive Potential and Total Lifespan of theSaccharomyces cerevisiaeYeast as Revealed by the Analysis of Polyploid Strains." Oxidative Medicine and Cellular Longevity 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/1898421.
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The total lifespan of the yeastSaccharomyces cerevisiaemay be divided into two phases: the reproductive phase, during which the cell undergoes mitosis cycles to produce successive buds, and the postreproductive phase, which extends from the last division to cell death. These phases may be regulated by a common mechanism or by distinct ones. In this paper, we proposed a more comprehensive approach to reveal the mechanisms that regulate both reproductive potential and total lifespan in cell size context. Our study was based on yeast cells, whose size was determined by increased genome copy number, ranging from haploid to tetraploid. Such experiments enabled us to test the hypertrophy hypothesis, which postulates that excessive size achieved by the cell—the hypertrophy state—is the reason preventing the cell from further proliferation. This hypothesis defines the reproductive potential value as the difference between the maximal size that a cell can reach and the threshold value, which allows a cell to undergo its first cell cycle and the rate of the cell size to increase per generation. Here, we showed that cell size has an important impact on not only the reproductive potential but also the total lifespan of this cell. Moreover, the maximal cell size value, which limits its reproduction capacity, can be regulated by different factors and differs depending on the strain ploidy. The achievement of excessive size by the cell (hypertrophic state) may lead to two distinct phenomena: the cessation of reproduction without “mother” cell death and the cessation of reproduction with cell death by bursting, which has not been shown before.
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Sinclair, A. R. E., Dennis Chitty, Carol I. Stefan, and Charles J. Krebs. "Mammal population cycles: evidence for intrinsic differences during snowshoe hare cycles." Canadian Journal of Zoology 81, no. 2 (February 1, 2003): 216–20. http://dx.doi.org/10.1139/z03-006.
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Some mammals in high northern latitudes show regular population cycles. In snowshoe hares (Lepus americanus), these occur every 910 years. One hypothesis proposes extrinsic causes such as food shortage or predation. The other proposes intrinsic causes through different morphs that alternate between different phases of the cycle. The morphs should differ in behaviour or physiology. This hypothesis predicts that animal lineages bred from high and low phases of the population cycle should differ in reproduction and survivorship. In a 16-year breeding program, lineages of purebred high-phase female hares had reduced reproductive rates relative to those of purebred low-phase females, resulting in extinction of high-phase lineages. Reproductive output declined with age in high- but not low-phase animals. These lineages also differed in longevity and senescence. These results are consistent with the intrinsic hypothesis and suggest a mechanism for alternating population densities that could work synergistically with extrinsic causes like predation and food shortage.
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Mazzoni, Talita Sarah, Robie Allan Bombardelli, and Irani Quagio-Grassiotto. "Reproductive Biology of Neotropical Fishes: A Guide to Identification to the Gonadal Morphology During the Reproductive Cycle of Catfish Rhamdia quelen (Siluriformes: Heptapteridae)." Aquatic Science and Technology 8, no. 2 (June 29, 2020): 15. http://dx.doi.org/10.5296/ast.v8i2.17102.
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In most Teleostei fish, the gametogenesis is a cyclical and seasonal event. The renewal of gametes, through their differentiation, development, maturation and release causes several changes in the morphological characteristics of the ovaries and testes throughout the annual reproductive cycles. These alterations are used to recognize different phases in the reproductive cycles. However, as the number of studies of fish reproduction increased, the number of types of gonadal classification and nomenclatures also diversified. This may make it difficult to communication between researchers and the aquaculture activity, since the recognition of these phases is one of the most important parameters applied in the management of fishery resources. In addition, the terminologies proposed in most of the current studies refer to reproductive stages applicable to marine fish, with marked and defined seasonality characteristics. In this way, this report presents a recent proposal for the recognition of reproductive phases originally developed for the Perciformes and here adapted for the Neotropical Siluriformes, using as a biological model a freshwater catfish Rhamdia quelen. In addition, we describe a brief characterization of the gametogenesis in this species. We hope that the material presented can be used as an easy and practical guide of identification for reproductive phases applicable to other neotropical freshwater fish, more especially Otophysi, such as Siluriformes.
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Christopher, Dorothy A., Randall J. Mitchell, and Jeffrey D. Karron. "Pollination intensity and paternity in flowering plants." Annals of Botany 125, no. 1 (October 5, 2019): 1–9. http://dx.doi.org/10.1093/aob/mcz159.
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Abstract Background Siring success plays a key role in plant evolution and reproductive ecology, and variation among individuals creates an opportunity for selection to act. Differences in male reproductive success can be caused by processes that occur during two stages, the pollination and post-pollination phases of reproduction. In the pollination phase, heritable variation in floral traits and floral display affect pollinator visitation patterns, which in turn affect variation among plants in the amount of pollen exported and deposited on recipient stigmas. In the post-pollination phase, differences among individuals in pollen grain germination success and pollen tube growth may cause realized paternity to differ from patterns of pollen receipt. The maternal plant can also preferentially provision some developing seeds or fruits to further alter variation in siring success. Scope In this review, we describe studies that advance our understanding of the dynamics of the pollination and post-pollination phases, focusing on how variation in male fitness changes in response to pollen limitation. We then explore the interplay between pollination and post-pollination success, and how these processes respond to ecological factors such as pollination intensity. We also identify pressing questions at the intersection of pollination and paternity and describe novel experimental approaches to elucidate the relative importance of pollination and post-pollination factors in determining male reproductive success. Conclusions The relative contribution of pollination and post-pollination processes to variation in male reproductive success may not be constant, but rather may vary with pollination intensity. Studies that quantify the effects of pollination and post-pollination phases in concert will be especially valuable as they will enable researchers to more fully understand the ecological conditions influencing male reproductive success.
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Millesi, Eva, Anna Strauss, Tamara Burger, Ilse E. Hoffmann, and Manfred Walzl. "Follicular development in European ground squirrels (Spermophilus citellus) in different phases of the annual cycle." REPRODUCTION 136, no. 2 (August 2008): 205–10. http://dx.doi.org/10.1530/rep-08-0090.
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In seasonally breeding mammals, in particular hibernators, reproduction underlies severe energetic and temporal constraints to enable the allocation of sufficient body fat reserves before winter. Thus, the timing of conception in spring can be crucial in terms of reproductive success. This study investigates follicular development in European ground squirrels (Spermophilus citellus) in three phases of the annual cycle: at vernal emergence, after weaning the offspring and shortly before hibernation. The animals were kept in outdoor enclosures within the natural habitat of the species. They were captured in weekly intervals, weighed and reproductive status was determined. Unilateral ovariectomy was scheduled such that the three periods were sampled. Numbers and diameters of tertiary follicles (TF) and corpora lutea (CL) in each ovary were determined, and plasma oestradiol and progesterone levels were analysed. The highest numbers of TF, including Graafian follicles, were found in ovaries at vernal emergence. During post-lactation, the number of TF was lower and active CL appeared in the investigated ovaries. Shortly before hibernation, active CL were present, but luteolysis had started in some individuals. Both oestradiol and progesterone secretion peaked after the termination of lactation and decreased before hibernation. The results demonstrate a second oestrus cycle in European ground squirrels after weaning, including an active luteal phase. This non-reproductive oestrus cycle with its endocrine output is an intriguing phenomenon. It may positively affect both prehibernatory fattening and reproduction in the subsequent season.
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Nunes-Silva, Patrícia, Sergio Dias Hilário, Pérsio de Souza Santos Filho, and Vera Lucia Imperatriz-Fonseca. "Foraging Activity inPlebeia remota, a Stingless Bees Species, Is Influenced by the Reproductive State of a Colony." Psyche: A Journal of Entomology 2010 (2010): 1–16. http://dx.doi.org/10.1155/2010/241204.
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Colonies of the Brazilian stingless beePlebeia remotashow a reproductive diapause in autumn and winter. Therefore, they present two distinct reproductive states, during which colony needs are putatively different. Consequently, foraging should be adapted to the different needs. We recorded the foraging activity of two colonies for 30 days in both phases. Indeed, it presented different patterns during the two phases. In the reproductive diapause, the resource predominantly collected by the foragers was nectar. The majority of the bees were nectar foragers, and the peak of collecting activity occurred around noon. Instead, in the reproductive phase, the predominantly collected resource was pollen, and the peak of activity occurred around 10:00 am. Although the majority of the foragers were not specialized in this phase, there were a larger number of pollen foragers compared to the phase of reproductive diapause. The temperature and relative humidity also influenced the foraging activity.
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Stief, C. G. "Mecanismes des phases de l’erection." Andrologie 2, no. 1 (October 1992): 28–29. http://dx.doi.org/10.1007/bf03034592.
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Norris, Richard D., Richard M. Corfield, and Julie Cartlidge. "What is gradualism? Cryptic speciation in globorotaliid foraminifera." Paleobiology 22, no. 3 (1996): 386–405. http://dx.doi.org/10.1017/s0094837300016341.
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Analysis of the evolution of the Globorotalia (Fohsella) lineage of planktic foraminifera suggests that reproductive ecology and shell shape have evolved independently in this group. The silhouette of fohsellid shells displays a nearly unbroken anagenetic trend, yet isotopic data show that the fohsellids changed their depth of reproduction during the anagenetic evolution of their skeletons. Remarkably, there are no correlations between anagenesis in skeletal shape and the establishment of reproductive isolation. Apparently, anagenesis masks at least one speciation event that is apparent only in the isotopic evidence for a change in reproductive ecology. Although anagenetic trends have been widely cited as evidence for gradual speciation in planktic foraminifera and other microfossil groups, our data suggest that they should not always be considered to record either the tempo or mode of speciation.Speciation was apparently uncoupled from morphological evolution in fohsellids because these evolutionary phenomena occurred in different phases of ontogeny. Gradual morphological changes were associated with the main phase of shell growth of both the ancestor and descendant species in the near-surface ocean. Reproductive isolation occurred when ancestral and descendant populations became established at different depths near the end of the life cycle. Morphological evolution may also be uncoupled from reproductive isolation in other organisms that experience very different selection pressures over the duration of their ontogenies, such as parasites with many hosts, species with multiple phases of metamorphosis, and organisms that broadcast their gametes.
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Plexico, Laura W., Mary J. Sandage, Heidi A. Kluess, Ana M. Franco-Watkins, and Leslie E. Neidert. "Blood Plasma Hormone–Level Influence on Vocal Function." Journal of Speech, Language, and Hearing Research 63, no. 5 (May 22, 2020): 1376–86. http://dx.doi.org/10.1044/2020_jslhr-19-00224.
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Purpose This preliminary study examined the influence of menstrual cycle phase and hormone levels on acoustic measurements of vocal function in reproductive and postmenopausal females. Mean fundamental frequency (f0), speaking fundamental frequency (Sf0), and cepstral peak prominence (CPP) were evaluated. It was hypothesized that Sf0 and CPP would be lower during the luteal and ischemic phases of the menstrual cycle. Group differences with lower values in postmenopausal females and greater variability in the reproductive females were also hypothesized. Method A mixed factorial analysis of variance was used to examine differences between reproductive and postmenopausal females and the four phases of the menstrual cycle. Separate analyses of variances were implemented for each of the dependent measures. Twenty-eight female participants (15 reproductive cycling, 13 postmenopausal) completed the study. Participants were recorded reading the Rainbow Passage and sustaining the vowel /a/. Mean vocal f0, Sf0, and CPP were determined from the acoustic samples. Blood assays were used to determine estrogen, progesterone, testosterone, and neuropeptide Y levels at four data collection time points. Results Group differences in hormone levels and Sf0 values were established with the postmenopausal group having significantly lower hormone levels and significantly lower Sf0 than the reproductive cycling group across the phases. Analysis of the reproductive group by hormone levels and cycle phase revealed no significant differences for CPP or Sf0 across phases. Higher estrogen was identified in the ovulation phase, and higher progesterone was identified in the luteal phase. Conclusions Significant differences in hormone levels and Sf0 were identified between groups. Within the reproductive cycling group, the lack of significant difference in acoustic measures relative to hormone levels indicated that the measures taken may not have been sensitive enough to identify hormonally mediated vocal function changes. The participant selection may have biased the findings in that health conditions and medications that are known to influence voice function were used as exclusion criteria.
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González, Fernanda G., Gustavo A. Slafer, and Daniel J. Miralles. "Vernalization and photoperiod responses in wheat pre-flowering reproductive phases." Field Crops Research 74, no. 2-3 (March 2002): 183–95. http://dx.doi.org/10.1016/s0378-4290(01)00210-6.
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Farooq, Muhammad, Helen Bramley, Jairo A. Palta, and Kadambot H. M. Siddique. "Heat Stress in Wheat during Reproductive and Grain-Filling Phases." Critical Reviews in Plant Sciences 30, no. 6 (November 2011): 491–507. http://dx.doi.org/10.1080/07352689.2011.615687.
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KVIST, S. BÉATRICE M., and RITVA-KAJSA SELANDER. "Open-field thigmotaxis during various phases of the reproductive cycle." Scandinavian Journal of Psychology 35, no. 3 (September 1994): 220–29. http://dx.doi.org/10.1111/j.1467-9450.1994.tb00946.x.
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Aguirre, Alejandro A., Roberto A. Palomares, Aitor D. De Ondiz, Eleazar R. Soto, Mariana S. Perea, Hugo J. Hernández-Fonseca, and Fernando P. Perea. "Lunar Cycle Influences Reproductive Performance of Crossbred Brahman Cows Under Tropical Conditions." Journal of Biological Rhythms 36, no. 2 (January 14, 2021): 160–68. http://dx.doi.org/10.1177/0748730420983638.
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Evidence has accumulated over the years indicating that the moon influences some aspects of the reproductive activity in animals and humans. However, little is known about the influence of the lunar cycle on the reproductive performance of cows under tropical conditions, where the environment strongly affects reproduction. This retrospective study was conducted with the aim of assessing the influence of the lunar cycle on some reproductive traits of tropical crossbred cows managed in a pasture-based system. Data from 5869 reproductive records from two commercial farms localized in the Maracaibo Lake Basin of Zulia State, Venezuela, were analyzed. Variables studied were first service conception rate, calving frequency, first postpartum estrous frequency, and pregnancy frequency. In addition to the lunar cycle, the effects of farm, season, and predominant breed were also considered. Data were analyzed using logistic regression and general linear model from SAS. First service conception was affected by lunar phases and predominant breed, but not by farm or season. For frequencies of calving, first postpartum estrus, and pregnancy, there was no main effect of farm, season, and predominant breed, whereas the effect of lunar phases was highly significant. First service conception was significantly greater in waning than in crescent phase of the lunar cycle. Frequencies of calving, first estrus, and pregnancy were highly correlated and showed greater figures around full moon and new moon. In conclusion, lunar cycle influenced first service conception, attaining greater values in the waning phase of the moon cycle. Frequencies of calving, first postpartum estrus, and pregnancy in crossbred cows showed a clear bimodal rhythm, whose greatest values coincided with new moon and full moon.
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Holekamp, Kay E., and Eli D. Strauss. "Reproduction Within a Hierarchical Society from a Female’s Perspective." Integrative and Comparative Biology 60, no. 3 (July 15, 2020): 753–64. http://dx.doi.org/10.1093/icb/icaa068.
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Abstract The reproductive biology of many female mammals is affected by their social environment and their interactions with conspecifics. In mammalian societies structured by linear dominance hierarchies, such as that of the spotted hyena (Crocuta crocuta), a female’s social rank can have profound effects on both her reproductive success and her longevity. In this species, social rank determines priority of access to food, which is the resource limiting reproduction. Due largely to rank-related variation in access to food, reproduction from the perspective of a female spotted hyena can only be understood in the context of her position in the social hierarchy. In this review, we examine the effects of rank on the various phases of reproduction, from mating to weaning. Summed over many individual reproductive lifespans, the effect of rank at these different reproductive phases leads to dramatic rank-related variation in fitness among females and their lineages. Finally, we ask why females reproduce socially despite these apparent costs of group living to low-ranking females. Gregariousness enhances the fitness of females regardless of their positions in the social hierarchy, and females attempting to survive and reproduce without clanmates lose all their offspring. The positive effects of gregariousness appear to result from having female allies, both kin and non-kin, who cooperate to advertise and defend a shared territory, acquire, and defend food resources, maintain the status quo, and occasionally also to rise in social rank.
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Chandavar, Vidya R., and Prakash R. Naik. "Seasonal variation in thyroid activity of turtle Lissemys punctata with respect to annual cycle of reproduction." Journal of Applied and Natural Science 2, no. 2 (December 1, 2010): 194–99. http://dx.doi.org/10.31018/jans.v2i2.119.
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The objective of the present investigation was to study the relationship between thyroid activity and reproductive cycle in turtle Lissemys punctata. The animals were studied in the annual seasonal cycle of reproduction for two consecutive years, which is distinguished into three separate periods namely regenerative, reproductive and recrudescent. The thyroid in L. punctata was observed to be a single pyramid shaped gland, creamy white to reddish-brown in color with lenticular profile. The diameter of the follicle was lowest in regenerative period, whichgradually increased in reproductive period attaining maximum size in recrudescent, where as epithelial height was highest in regenerative period, which gradually decreased in reproductive period reaching minimum in recrudescent period. Thyroid activity varies annually in relation to different phases of reproductive periods.
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Mello, Romulo Teixeira, Cristina Hueb Barata, Paulo Marcos Zech Coelho, and Aluízio Prata. "Influence of Schistosoma mansoni infection on the reproductive capacity of albino mice." Revista da Sociedade Brasileira de Medicina Tropical 31, no. 6 (December 1998): 579–80. http://dx.doi.org/10.1590/s0037-86821998000600013.
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This paper reports reduction on the reproductive capacity of female mice infected with Schistosoma mansoni, either in the acute phase or in the chronic one of the disease. This decrease in the reproductive capacity was highly significant (93.3% and 86.7%, for the acute and chronic phases, respectively)..
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Góngora-Gómez, Andrés Martín, Carlos Humberto Sepúlveda, Héctor Alejandro Verdugo Escobar, Osvaldo Astorga Castro, Hervey Rodríguez-González, Ana Laura Domínguez-Orozco, Juan Antonio Hernández-Sepúlveda, and Manuel García-Ulloa. "Gonadal maturity of Crassostrea corteziensis cultivated in the Gulf of California." Latin American Journal of Aquatic Research 48, no. 3 (July 6, 2020): 381–95. http://dx.doi.org/10.3856/vol48-issue3-fulltext-2422.
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The gonadal maturation of the pleasure oyster Crassostrea corteziensis during four cultivation cycles (November 2004-June 2005, N4J5; August 2014-February 2016, A14F16; September 2015-December 2016, S15D16; September 2016-August 2017, S16A17) was studied in the southeastern Gulf of California, Mexico. Although C. corteziensis exhibited the typical reproductive phases (undifferentiated or resting, initial gametogenesis, advanced gametogenesis, maturity, spawning and post-spawning), the intensity of reproduction and the timing of the onset of the different phases of gonadal development varied in each cultivation cycle. Reproductive peaks were observed in different months (N4J5 in May, A14F16 in July, S15D16 in May and S16A17 in June) during spring and summer. Spawning correlated with temperature in the N4J5 and A14F16 cultivation cycles but it showed no correlation with chlorophyll-a concentration in any of the cultivation cycles. C. corteziensis presented an opportunistic continuous reproductive strategy with spawning occurring during several months of the year. The modification of the species' reproduction pattern could contribute to the natural settlement of larvae, increasing the natural production of this native oyster resource in the southeast of the Gulf of California, where it has been fished intensively.
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Medini, R., M. Bhagya, and S. Samson. "Seasonal changes in the protein profile and enzyme activity of the epididymal luminal fluid in the lizard, Eutropis carinata (Schneider, 1801)." Animal Biology 68, no. 4 (2018): 387–404. http://dx.doi.org/10.1163/15707563-17000124.
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Abstract The epididymis of the male reproductive system is known to be involved in sperm maturation via the production of polypeptides, glycoproteins, surface proteins, enzymes and other factors. During the annual reproductive cycle, the epididymis of the lizard Eutropis carinata undergoes dramatic changes, both morphologically and biochemically, that occur in a well-organized sequence. The present study reveals the sequential changes that occur in the production and concentration of proteins in the epididymal luminal fluid throughout the annual reproductive cycle. A one-dimensional electrophoretic profile of the epididymal luminal proteins revealed a total of 18 bands in the regenerative phase, 22 bands during breeding and 17 bands in the post-breeding as well as regressed phases of the reproductive cycle. By two-dimensional electrophoresis, the protein complexes that are unique to the breeding phase were further resolved based on their pI and the molecular weight of each protein of the protein complex was determined. This is the first study to observe that proteins that are present during the reproductively inactive phase disappear during the reproductively active phase. The Periodic Acid Schiff (PAS) test for protein profiles revealed the presence of proteins with a carbohydrate moiety. Certain enzymes, such as acid phosphatase, alkaline phosphatase, and α-glucosidase, are highly sensitive to seasonal changes and their activity parallels the production of the epididymal proteins. This study provides evidence for androgen-dependent cyclical changes in the pattern of protein profiles and enzyme activity of the epididymal lumen in the lizard E. carinata.
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Teixeira, Paulo Sérgio Dos Santos, Ana Silvia A. M. T. Moura, Francisco S. Wechsler, Simone Fernandes, and Vânia G. M. Mattaraia. "Diet density in rearing and reproductive phases influences carcass composition, pregnancy rate and litter performance of primiparous rabbit does." World Rabbit Science 25, no. 2 (June 28, 2017): 147. http://dx.doi.org/10.4995/wrs.2017.6509.
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The objective was to evaluate the effect of the interaction of diet density in the rearing phase×diet density in the reproductive phase on carcass composition, pregnancy rate, and litter performance of primiparous rabbit does. The experiment followed a 2×2×2 factorial (2 seasons, 2 diet densities in the rearing phase and 2 diet densities in reproductive phase, that is, from mating to weaning of the first litter). The reference diet (RD) contained 184 g/kg of crude protein (CP), 165 g/kg of acid detergent fibre (ADF) and 10.5 MJ/kg of digestible energy (DE). The low-density diet (LD) had 147 g/kg of CP, 24 g/kg of ADF and 8.4 MJ/kg of DE. The treatments were applied from 70 d of age until weaning of the first litter at 35 d of age. Ninety-six females from the Botucatu Genetic Group (24 females/experimental group) were mated at 142 d of age. On day 12 of gestation, 23 does were slaughtered to evaluate weights of carcass, organs and dissectible fat, and embryo implantation rate. No effects of diet density in the rearing or in the reproductive phases were detected on feed intake of does during the reproductive phase. Does fed LD during the rearing phase showed lower body weight at mating (3574±47 vs. 3866±43 g, P=0.0001) and during most of the reproductive phase, but they lost less weight in the peripartum. Perirenal fat was lighter in these does (72.8±10.0 vs. 102.1±9.6 g, P=0.048) and they showed a lower pregnancy rate (76.1 vs. 91.7%, P=0.045). The does fed RD in the reproductive phase were heavier during this phase (4055±40 g vs. 3887±41 g, P=0.0044). The does fed LD in rearing phase and RD in the reproductive phase showed larger litters at weaning, due to decreased kit mortality, than those fed RD in both phases (6.16±0.47 vs. 3.93±0.71, P=0.0361). Litters were lighter at weaning when LD was fed in the reproductive phase (3582±201 vs. 4733±187, P<0.0001). Feeding a low-density diet during the rearing phase and a reference diet during the reproductive phase is the best alternative to improve reproductive performance at the first parity.
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Jana, A., and S. P. Sen. "Influence of cellular metabolites on RNA and protein syntheses by Xanthium nuclei of different developmental phases." Canadian Journal of Botany 64, no. 12 (December 1, 1986): 2922–27. http://dx.doi.org/10.1139/b86-386.
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Leaf nuclei of vegetative and reproductive plants of Xanthium strumarium L. were incubated with the postribosomal supernatant of either phase and changes at the transcriptional level were studied in homologous and heterologous combinations. In the presence of the supernatant of reproductive plants, RNA synthesis by vegetative nuclei was decreased by 25%. Reproductive nuclei were less active in RNA synthesis. Gel electrophoretic studies revealed four RNA bands in vegetative nuclei incubated with reproductive supernatant, including a fast-moving low molecular weight band that could not be detected when the "vegetative" supernatant was used. The adenine/uracil ratios of the newly synthesized RNA of vegetative nuclei treated with vegetative and reproductive supernatants were 1.46 and 1.54, respectively, compared with 1.15 and 1.04 in the reproductive nuclei. Competitive DNA–RNA hybridization experiments indicated that about 2% of the [3H]RNA synthesized by nuclei of vegetative plants in the presence of the supernatant of reproductive plants could not be beaten out by the RNA of vegetative plants. Small quantitative differences, thus, may be expected in the RNA molecules synthesized by nuclei in the presence of the supernatant fraction of vegetative and reproductive plants. The supernatant fraction of the reproductive tissues decreased the incorporation of [3H]alanine and [3H]leucine in both the buffer-soluble and acid-soluble proteins and the nuclei of vegetative plants were more active in protein synthesis. Protein patterns as studied by acrylamide gel electrophoresis revealed alterations when vegetative leaf nuclei were incubated with the supernatant of reproductive tissues.
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Alzahrani, Faisal, and Fathelrahman Hassan. "Modulation of Platelet Functions Assessment during Menstruation and Ovulatory Phases." Journal of Medicine and Life 12, no. 3 (July 2019): 296–300. http://dx.doi.org/10.25122/jml-2019-0005.
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During menstruation, endometrial hemostasis is achieved by platelet aggregation, fibrin deposition, and thrombus formation that interact with local endocrine and immunological factors which cause termination of menstrual bleeding. Interactions between steroidal sex hormones and platelet functions are not well understood. The aim of this study was to evaluate the effect of platelet function during the menstrual cycle and luteal phase in women of reproductive age. The cross-sectional study on women of reproductive age included 44 healthy women. Platelet function was assessed by PFA-100TM analyzer with collagen/epinephrine and collagen/ADP cartridges during the menstrual cycle and luteal phase. There were no significant differences in platelet function between menstruation and ovulatory phase. Platelet activity in Arab collagen/epinephrine cartridge increased during menstruation compared to non-Arab ethnic subjects and no significant differences in platelet function were found when using collagen/ADP cartridge. This study suggested modulation in platelet functions during menstruation and luteal phase in women of reproductive age. Further studies, including a large number of subjects, platelet genetic and progesterone factors change in platelet clotting associated to menstrual cycle should be conducted.
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Vignoli, Leonardo, Manuela D’Amen, Francesca Della Rocca, Marco A. Bologna, and Luca Luiselli. "Contrasted influences of moon phases on the reproduction and movement patterns of four amphibian species inhabiting different habitats in central Italy." Amphibia-Reptilia 35, no. 2 (2014): 247–54. http://dx.doi.org/10.1163/15685381-00002943.
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Many studies have provided evidence that prey adjust their behaviour to adaptively balance the fitness effects of reproduction and predation risk. Nocturnal terrestrial animals should deal with a range of environmental conditions during the reproductive season at the breeding sites, including a variable amount of natural ambient light. High degrees of illumination are expected to minimize those behaviours that might increase the animal detection by predators. Therefore, under habitat variable brightness conditions and in different ecosystems, the above mentioned behaviours are expected to depend on the variation in predation risk. Although moon effects on amphibian biology have been recognized, the direction of this influence is rather controversial with evidences of both increased and depressed activity under full moon. We tested in four nocturnal amphibian species (Hyla intermedia, Rana dalmatina, Rana italica, Salamandrina perspicillata) the effects of different (i) light conditions and (ii) habitats (open land vs. dense forest) on the reproductive phenology. Our results showed that the effects of the lunar cycle on the study species are associated with the change in luminosity, and there is no evidence of an endogenous rhythm controlled by biological clocks. The habitat type conditioned the amphibian reproductive strategy in relation to moon phases. Open habitat breeders (e.g., ponds with no canopy cover) strongly avoided conditions with high brightness, whereas forest habitat breeders were apparently unaffected by the different moon phases. Indeed, for all the studied species no effects of the moon phase itself on the considered metrics were found. Rather, the considered amphibian species seem to be conditioned mainly by moonlight irrespective of the moon phase. The two anurans spawning in open habitat apparently adjust their oviposition timing by balancing the fitness effects of the risk to be detected by predators and the reproduction.
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Izmaiłow, Romana. "Reproductive strategy in the Ranunculus auricomus complex (ranunculaceae)." Acta Societatis Botanicorum Poloniae 65, no. 1-2 (2014): 167–70. http://dx.doi.org/10.5586/asbp.1996.029.
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A preliminary study of reproductive strategy was carried out on plants representing four cytotypes of the <em>Ranunculus auricomus</em> complex. Diploid plants reproduce sexually, triploids, tetraploids and hexaploids have an apomictic mode of reproduction (apospory combined with pseudogamy). Some morphological characters of the plants connected with reproduction were analyzed at various phases and compared in two successive seasons. The following characters were estimated at the individual level: number of ovules and primary pollen grains per plant, pollen viability, pollen-ovule ratio, number of achenes per plant and their germinability, seed-ovule ratio. Most of data characteristic of reproductive strategy were calculated according to the formulae proposed by Urbańska (1989, 1990). Apomictic cytotypes have both a significantly lower pollen viability and seed-ovule ratio (the lowest values in triploids) than sexual diploids.
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Farooq, Muhammad, Faisal Nadeem, Nirmali Gogoi, Aman Ullah, Salem S. Alghamdi, Harsh Nayyar, and Kadambot H. M. Siddique. "Heat stress in grain legumes during reproductive and grain-filling phases." Crop and Pasture Science 68, no. 11 (2017): 985. http://dx.doi.org/10.1071/cp17012.
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Thermal stress during reproductive development and grain-filling phases is a serious threat to the quality and productivity of grain legumes. The optimum temperature range for grain legume crops is 10−36°C, above which severe losses in grain yield can occur. Various climatic models have simulated that the temperature near the earth’s surface will increase (by up to 4°C) by the end of this century, which will intensify the chances of heat stress in crop plants. The magnitude of damage or injury posed by a high-temperature stress mainly depends on the defence response of the crop and the specific growth stage of the crop at the time of exposure to the high temperature. Heat stress affects grain development in grain legumes because it disintegrates the tapetum layer, which reduces nutrient supply to microspores leading to premature anther dehiscence; hampers the synthesis and distribution of carbohydrates to grain, curtailing the grain-filling duration leading to low grain weight; induces poor pod development and fractured embryos; all of which ultimately reduce grain yield. The most prominent effects of heat stress include a substantial reduction in net photosynthetic rate, disintegration of photosynthetic apparatus and increased leaf senescence. To curb the catastrophic effect of heat stress, it is important to improve heat tolerance in grain legumes through improved breeding and genetic engineering tools and crop management strategies. In this review, we discuss the impact of heat stress on leaf senescence, photosynthetic machinery, assimilate translocation, water relations, grain quality and development processes. Furthermore, innovative breeding, genetic, molecular and management strategies are discussed to improve the tolerance against heat stress in grain legumes.
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Siqueira-Silva, Diógenes Henrique de, Carlos Alberto Vicentini, Alexandre Ninhaus-Silveira, and Rosicleire Veríssimo-Silveira. "Reproductive cycle of the Neotropical cichlid yellow peacock bass Cichla kelberi: A novel pattern of testicular development." Neotropical Ichthyology 11, no. 3 (September 2013): 587–96. http://dx.doi.org/10.1590/s1679-62252013000300012.
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The present study describes the testicular maturation phases (associating the germ cells development and the morphological changes suffered by the germinal epithelium along the whole year), and the testicular morphology in the yellow peacock bass Cichla kelberi, relating it to other species. For this purpose, 78 specimens were studied according conventional techniques of light microscope. The testes in C. kelberi were classified as unrestricted spermatogonial lobular, an apomorphic characteristic in the recent groups of Teleost. Furthermore, were defined five testicular maturation phases: Preparatory phase; Early Germinal Epithelium Development; Mid Germinal Epithelium Development; Late Germinal Epithelium Development and; Regression. Similar classifications were described to other species indicating that the testicular classifications based on this propose, can be applied to lots of fishes. However, besides it similarity, the testicular reproductive cycle of C. kelberifollows a different pattern in the Regression phase, on which the gonadal restructuration and the spermatogonial proliferation gathers at the same time. So, the testes in C. kelberi never return to the Preparatory phase to start a new reproductive cycle, being this one present only at the first reproductive cycle in this species. This fact also explains the absence of individuals totally spent after their first reproductive cycle.
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Watanabe, Dai, Toru Hoshiya, Junko Sato, Yuko Yamaguchi, Kohsuke Horiguchi, Yoshikazu Nagashima, Azusa Okaniwa, and Hiroyasu Yoshikawa. "Changes in the Reproductive Organs Depending on Phases of Reproductive Cycle and Aging in Female Cynomolgus Monkeys." Journal of Toxicologic Pathology 19, no. 4 (2006): 169–77. http://dx.doi.org/10.1293/tox.19.169.
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Shanbhag, Bhagyashri, Srinivas Saidapur, and Rajkumar Radder. "Big boys on top: effects of body size, sex and reproductive state on perching behaviour in the tropical rock dragon, Psammophilus dorsalis." Animal Biology 56, no. 3 (2006): 311–21. http://dx.doi.org/10.1163/157075606778441903.
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AbstractPerching behaviour, in relation to sex, body size and reproductive phases, was studied in the field in a population of the tropical rock lizard, Psammophilus dorsalis. Adult lizards (n = 14 males and 16 females) were marked by toe clipping in November 2001. They were observed at intervals (n = 10 times) over the next 18 months encompassing post-breeding (December-early March), recrudescence (late March-April) and breeding (May-August) phases. In the post-breeding phase, males perched at lower heights. They began perching higher during the recrudescence phase with the highest perches in the breeding phase. In comparison to females, the males perched higher than females all year round and showed greater among-individual variations in perch height. The bigger males perched at greater heights compared to smaller ones during recrudescence and breeding phases. No such trend was evident during the post-breeding phase and perch height was not related to body size. Females moved within a narrow range of heights from the substrata and showed no size-specific relationship in perch selection throughout the reproductive cycle. Selection of higher perches by the males, despite high predation risk, possibly helps in territory defence, courtship displays and in advertising their presence to conspecifics. Further, size-specific perch selection prior to and during the breeding period, suggests that size vis-à-vis age and reproductive cycle also influences selection of perch height in males. In females perching close to the substrata, refuge sites and food sources, seems to be associated with escape from predators, foraging benefits and, in turn, reproductive fitness. Thus, in the seasonally breeding P. dorsalis, sex and reproductive status determine the complex pattern of perching behaviour and, possibly, circulating levels of androgens drive the bigger boys on top in accordance with their size or age.
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Zhang, Jiayin, Seunghyun Choi, Jingping Fan, and Hye-Ji Kim. "Biomass and Phosphorus Accumulation and Partitioning of Geranium and Coleus in Response to Phosphorus Availability and Growth Phase." Agronomy 9, no. 12 (November 28, 2019): 813. http://dx.doi.org/10.3390/agronomy9120813.
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This study was conducted to examine plant biomass and phosphorus (P) accumulation and partitioning in response P availability and to determine the optimal P concentration during growth phases of two plant species with contrasting growth characteristics: geranium (Pelargonium × hortorum Bailey) “Bullseye Scarlet”, a flowering plant, and coleus (Solenostemon scutellarioides (L.) Codd) “Chocolate Mint”, a foliage plant. Plants were grown in inert media (1:1 mixture of perlite and vermiculite) with complete nutrient solutions containing a range of P concentrations considered low (3 and 5 mg/L), intermediate (10 and 15 mg/L), and high (20 and 30 mg/L). Higher P rates logarithmically increased shoot and root dry mass of geranium and coleus plants regardless of the growth phase, but linearly enhanced flower dry mass of reproductive geranium plants resulting from the accelerated flower development. During the vegetative phase, the intermediate-P increased the shoot biomass production of geranium plants, but high-P was more effective for coleus plants. During the reproductive phase, however, the intermediate-P increased shoot biomass production of both geranium and coleus plants to the level achieved by high-P. The change from vegetative to reproductive phase increased the relative biomass to flowers, roots, and shoots of reproductive geranium plants and roots and shoots of reproductive coleus plants in decreasing orders, resulting in an increased root-to-shoot ratio. The P content of all plant parts showed a logarithmical increase with higher P rates for reproductive geranium plants but a linear increase for reproductive coleus plants. During the reproductive phase, a higher proportion of acquired P was allocated to flowers of low-P geranium plants than the roots of high-P coleus. Our results demonstrate that geranium plants require intermediate-P throughout the growth phases, while coleus plants require high-P during the vegetative phase and intermediate-P during the reproductive phase. P-use efficiency (PUE) ranged from 5 to 15% in high-P, which was improved with intermediate-P by 36 to 70%. To further improve PUE, the application method also needs to be taken into consideration such that the fertigation volume is reduced during the vegetative phase and increased before the reproductive phase.
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Oliveira, Mônica Rocha de, and Sathyabama Chellappa. "Temporal Dynamics of Reproduction inHemiramphus brasiliensis(Osteichthyes: Hemiramphidae)." Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/837151.
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The reproductive aspects ofHemiramphus brasiliensiswere analyzed with a view to verify the temporal dynamics of reproduction. This paper presents data on sex ratio, length at first sexual maturity, macroscopic and histological aspects of gonad development, gonadosomatic index (GSI), reproductive period, and fecundity ofH. brasiliensis. The fishes were captured from the coastal waters of Rio Grande do Norte, northeastern Brazil. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads ofH. brasiliensisshowed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species was 1153 (±258.22) mature oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate thatH. brasiliensisis a multiple spawner, presenting a prolonged reproductive period during the whole year, with a peak in the month of April, and is considered as an opportunistic strategist.
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Hickmann, Felipe, José Braccini Neto, Luke M. Kramer, Kent A. Gray, Yijian Huang, Jack C. Dekkers, Leticia P. Sanglard, and Nick V. Serão. "128 Differences in PRRSV Resilience for Reproductive Performance Between Landrace and Duroc Sows." Journal of Animal Science 99, Supplement_1 (May 1, 2021): 18–19. http://dx.doi.org/10.1093/jas/skab054.033.
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Abstract Studies on differences in resilience to porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) between breeds are scarce in the literature. Thus, the objective of this work was to assess PRRSV resilience in PRRSV wild-type infected sows from two breeds. Farrowing data included 2546 and 2522 litters from 894 Duroc and 813 Landrace sows, respectively, which were housed together and experienced the same PRRSV outbreak. Traits used for this study were number of piglets born alive (NBA), number born dead (NBD), total number born (TNB), and number weaned (NW). The impact of PRRSV infection was evaluated by comparing the reproductive performance of breeds between PRRS phases (pre-PRRS, PRRS, and post-PRRS). PRRS phases were defined based on the reproductive performance data. NBA, NBD, and NW were analyzed as a proportion of TNB using a Poisson mixed model. Pre-defined contrasts were used to evaluate the effect of breed on PRRSV resilience and on return to PRRSV-free performance, representing the differences between breeds for the difference between pre-PRRS and PRRS phases, and pre-PRRS and post-PRRS phases, respectively. There was a significant (P ≤ 0.003) interaction between PRRS phase and breed for all traits, as shown in Table 1. In general, reproductive performance reduced from pre-PRRS to PRRS, and then increased from PRRS to post-PRRS, as expected. The resilience contrast was significant for all traits (P ≤ 0.003). In all cases, the drop in percent reproductive performance from pre-PRRS to PRRS was lower for Duroc than for Landrace, indicating that Duroc sows have greater PRRSV resilience than Landrace sows. The return to PRRSV-free performance contrast had a trending effect for NBD (P = 0.055), and it was not significant for the other traits (P ≥ 0.515). These results indicate that Duroc sows have overall greater phenotypic PRRSV resilience for reproductive performance than Landrace sows.
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Asilo, Sonia, Andrew Nelson, Kees de Bie, Andrew Skidmore, Alice Laborte, Aileen Maunahan, and Eduardo Jimmy P. Quilang. "Relating X-band SAR Backscattering to Leaf Area Index of Rice in Different Phenological Phases." Remote Sensing 11, no. 12 (June 20, 2019): 1462. http://dx.doi.org/10.3390/rs11121462.
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The objective of this study is to provide complete information on the dynamic relationship between X-band (3.11 cm) backscattering intensity (σ°) and rice crop’s leaf area index (LAI) at all growth phases. Though the relationship between X-band σ° and LAI has been previously explored, details on the relationship at the reproductive phase remain unstudied. LAI at the reproductive phase is important particularly at the heading stage where LAI reaches its maximum as it is closely related to grain yield, and at flowering stage where the total leaf area affects the amount of photosynthates. Therefore, this study examined the relationship of increasing LAI (vegetative to reproductive phase) and decreasing LAI (ripening phase) with TerraSAR-X (TSX) ScanSAR (3.11 cm) σ° at HH polarisation and 45° incidence angle. The results showed a statistically significant (R2 = 0.51, p value < 0.001) non-linear relationship of LAI with σ° at the vegetative to reproductive phase while no significant linear relationship was found at the ripening phase. This study completes the response curve of X-band σ° to LAI by filling in the information on the reproductive phase which more accurately characterises the dynamic relationship between the rice crop’s LAI and X-band’s σ°. This contributes to improved knowledge on the use of X-band data for estimating LAI for the whole crop cycle which is essential for the modelling of crop growth and estimation of yield.
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Weitten, Mathieu, Mathilde Louise Tissier, Jean-Patrice Robin, and Caroline Habold. "Dietary proteins improve hibernation and subsequent reproduction in the European hamster, Cricetus cricetus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 315, no. 4 (October 1, 2018): R848—R855. http://dx.doi.org/10.1152/ajpregu.00146.2018.
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The reproductive success of hibernators depends not only on food quality during reproduction but also on their body condition when emerging after hibernation, which, in turn, is highly dependent on the hibernation pattern. To date, no studies, to our knowledge, have fully investigated the role of macronutrients throughout the annual lifecycle of hibernators and the strong interdependency between its different phases. This study tested the effects of two diets with different lipid and protein composition on the prehibernation body condition, hibernation pattern, and reproduction of captive-reared European hamsters. Hamsters fed the high-lipid diet gained more body mass in the prehibernation period than those eating the high-protein diet, spent less time in torpor, and thus lost more body mass during hibernation. Despite similar body conditions in both groups at the start of reproduction, the group fed the high-protein diet had higher reproductive success, with more numerous and larger pups than in the high-lipid group. This study reveals that the macronutrient content of diets affects the different phases of the annual lifecycle in hamsters, each of which affects the next. Thus, a high-lipid diet induces less torpor use during hibernation because of a better prehibernation body condition and negatively impacts subsequent reproduction.
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Alicea, Bradly. "Evolution in eggs and phases: experimental evolution of fecundity and reproductive timing in Caenorhabditis elegans." Royal Society Open Science 3, no. 11 (November 2016): 160496. http://dx.doi.org/10.1098/rsos.160496.
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To examine the role of natural selection in fecundity in a variety of Caenorhabditis elegans genetic backgrounds, we used an experimental evolution protocol to evolve 14 distinct genetic strains over 15–20 generations. We were able to generate 790 distinct genealogies, which provided information on both the effects of natural selection and the evolvability of each strain. Among these genotypes are a wild-type (N2) and a collection of mutants with targeted mutations in the daf-c, daf-d and AMPK pathways. Differences are observed in reproductive fitness along with related changes in reproductive timing. The majority of selective effects on fecundity occur during the first few generations of evolution, while the negative selection for reproductive timing occurs on longer time scales. In addition, positive selection on fecundity results in positive and negative strain-dependent selection on reproductive timing. A derivative of population size per generation called reproductive carry-over (RCO) may be informative in terms of developmental selection. While these findings transcend mutations in a specific gene, changes in the RCO measure may nevertheless be products of selection. In conclusion, the broader implications of these findings are discussed, particularly in the context of genotype-fitness maps and the role of uncharacterized mutations in individual variation and evolvability.
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Pérez-Gianmarco, Thomas I., Gustavo A. Slafer, and Fernanda G. González. "Wheat pre-anthesis development as affected by photoperiod sensitivity genes (Ppd-1) under contrasting photoperiods." Functional Plant Biology 45, no. 6 (2018): 645. http://dx.doi.org/10.1071/fp17195.
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Fine tuning wheat phenology is of paramount importance for adaptation. A better understanding of how genetic constitution modulates the developmental responses during pre-anthesis phases would help to maintain or even increase yield potential as temperature increases due to climate change. The photoperiod-sensitive cultivar Paragon, and four near isogenic lines with different combinations of insensitivity alleles (Ppd-A1a, Ppd-B1a, Ppd-D1a or their triple stack) were evaluated under short (12 h) and long (16 h) photoperiods. Insensitivity alleles decreased time to anthesis and duration of the three pre-anthesis phases (vegetative, early reproductive and late reproductive), following the Ppd-D1a > Ppd-A1a > Ppd-B1a ranking of strength. Stacking them intensified the insensitivity, but had no additive effect over that of Ppd-D1a. The late reproductive phase was the most responsive, even exhibiting a qualitative response. Leaf plastochron was not affected but spikelet plastochron increased according to Ppd-1a ranking of strength. Earlier anthesis resulted from less leaves differentiated and a fine tuning effect of accelerated rate of leaf appearance. None of the alleles affected development exclusively during any particular pre-anthesis phase, which would be ideal for tailoring time to anthesis with specific partitioning of developmental time into particular phases. Other allelic variants should be further tested to this purpose.
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Teresa, Fabrício Barreto, and Eliane Gonçalves-de Freitas. "Reproductive behavior and parental roles of the cichlid fish Laetacara araguaiae." Neotropical Ichthyology 9, no. 2 (June 10, 2011): 355–62. http://dx.doi.org/10.1590/s1679-62252011005000018.
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We described the reproductive behavior of the small South American cichlid Laetacara araguaiae in streams from Brazil. We predicted that this species will show reproductive cooperation and division of labor between males and females in a similar way presented by other substrate-spawner cichlids. Thus, we studied 34 pairs in the pre-spawning (n = 11), egg/wriggler (n = 11) and fry (n = 12) phases. In the pre-spawning phase both sexes become involved in nest building and territorial defense, but females emphasizes building nest (p = 0.03), while males invest more time in territorial defense (p = 0.04). After spawning, male and female alternate between rearing eggs and defending nest in the territory. In the egg/wriggler phase females devotes more time rearing the brood while males remain defending territory (p = 0.02). These differences disappear when young are in the fry stage, and parents jointly stay closer to fry (p = 0.98). However, at this phase, there is a reduction in the frequency of threats shown by males (p<0.01) and an increase in the frequency of attacks shown by female (p<0.01) that could be a response to an increased demand for parental defense. Our results indicate that the reproductive cooperation between males and females of L. araguaiae is marked by division of labor in the early reproductive phases and by sharing of parental duties as brood develops.
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Beguelini, Mateus R., Cornélio S. Santiago, Eliana Morielle-Versute, and Sebastião R. Taboga. "Morphophysiological variations of the female reproductive organs of the vespertilionid bat Myotis nigricans during its different reproductive phases." Theriogenology 158 (December 2020): 121–37. http://dx.doi.org/10.1016/j.theriogenology.2020.09.004.
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Gíslason, Davíð, Moira M. Ferguson, Skúli Skúlason, and Sigurður S. Snorrason. "Rapid and coupled phenotypic and genetic divergence in Icelandic Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 12 (December 1, 1999): 2229–34. http://dx.doi.org/10.1139/f99-245.
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Resource polymorphism has been proposed as an important phase of diversification and speciation in vertebrates. Studies of fish in young lakes of the Northern Hemisphere indicate variably advanced cases of adaptive trophic diversification. We have previously proposed a scheme describing this variation in terms of a gradient of resource-based polymorphic traits, emphasizing flexible behaviour in early phases and morphological divergence in more advanced phases. Here, we present data on Arctic char (Salvelinus alpinus) in Icelandic lakes exhibiting a variable degree of phenotypic and genotypic segregation. We show that (i) the morphs are at different levels of phenotypic segregation and reproductive isolation and in one case completely reproductively isolated, (ii) morphs within lakes appear to be of intralacustrine origin, and (iii) the morphological and genetic divergence of morphs is correlated, suggesting a role for trophic adaptation as a driving force in morph segregation.
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Radovic, Bisa, Stoja Jotanovic, Djordje Savic, and Atanas Nitovski. "Blood biochemical parameters of simmental cows in different phases of reproductive cycle." Veterinarski glasnik 65, no. 3-4 (2011): 191–201. http://dx.doi.org/10.2298/vetgl1104191r.
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This paper presents the values of blood biochemical parameters of Simmental cows (n = 60), divided into five groups (dry cows, early puerperium, late puerperium, the fifth month of lactation, and cows with an extended service period). The ration for lactating cows contained an insufficient amount of dry matter, a third less than the lower limit of their requirements. In all examined groups of cows, a strong protein deficiency and excess calcium was found in the diet. Total protein concentration in all groups of cows were on the upper physiological limit, and the concentrations of bilirubin, carotene, vitamin A and total lipids were within the normal range. Low concentrations of urea in the third, fourth and fifth group of cows (3.1?0.39 mmol/l, 2.9?0.38 mmol/l and 3.3?0.43 mmol/l, respectively) indicate the imbalance of protein and energy in the diet. The presence of an energy deficit is also indicated by the low blood glucose in all groups of cows, especially the second and fifth groups of cows (2.2?0.04 mmol/l and 2.3?0.07 mmol/l, respectively). The unfavorable ratio of calcium and phosphorus in the diet resulted in the narrowing of the calcium:phosporus ratio in blood serum, which is particularly evident in cows with an extended service period (2.1?0.07 mmol/l compared to 1.9? 0.11 mmol/l). Based on these results,we conclude that the tested herd exhibits subclinical health disorders, caused by an inadequate diet and with adverse effects on the productive and reproductive parameters.
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Škvareninová, J. "Impact of climatic conditions on the reproductive phenological phases of European hazel (Corylus avellana L.) in Slovakia." Journal of Forest Science 62, No. 2 (June 3, 2016): 47–52. http://dx.doi.org/10.17221/55/2015-jfs.
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J., Karthiga Prabhu, Shanmugapriya C., Sunita Samal, and Balaji Ramraj. "Comparison of adnexal torsion in different phases of women’s life: a retrospective cohort study." International Journal of Reproduction, Contraception, Obstetrics and Gynecology 9, no. 4 (March 25, 2020): 1482. http://dx.doi.org/10.18203/2320-1770.ijrcog20201209.
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Background: Ovarian torsion is one of the most common causes of emergency surgery in gynecology. Though it is more common in reproductive age group, it can occur in extremes of age group. So, we had analysed the clinical presentation, surgical characteristics, and causes of adnexal torsion among adolescent population, reproductive-age women, and postmenopausal women.Methods: Patients with adnexal torsion who were treated in department of obstetrics and gynecology, SRM Medical College Hospital and Research Centre from October 2016 to March 2019 were retrospectively analyzed.Results: Among the 53 cases of adnexal torsion during the study period, maximum (38, 71.6%) were in the reproductive age group. There were three patients with ovarian torsion during pregnancy. Acute pain abdomen was the significant presenting symptom in adolescent group compared to other two group (100% versus 80.6% versus 40%, p = 0.03). Adnexal pathology was in the ovary in 76% and isolated tubal pathology in 5%. Bilateral salpingo-oophorectomy with or without total abdominal hysterectomy was more commonly performed in postmenopausal patients (100%), as opposed to conservative surgery- detorsion and cystectomy in premenopausal women (56%). In Adolescent patients 62% had polycystic ovaries as intraoperative finding. Histopathology were benign except for a patient in postmenopausal age group who had granulosa cell tumour.Conclusions: An early identification of adnexal torsion is necessary in order to achieve conservative treatment in order to maximize the future reproductive potential in younger patients.
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Jayasena, Channa N., Alexander N. Comninos, Akila De Silva, Ali Abbara, Johannes D. Veldhuis, Gurjinder M. K. Nijher, Zainab Ganiyu-Dada, et al. "Effects of Neurokinin B Administration on Reproductive Hormone Secretion in Healthy Men and Women." Journal of Clinical Endocrinology & Metabolism 99, no. 1 (January 1, 2014): E19—E27. http://dx.doi.org/10.1210/jc.2012-2880.
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Background: Neurokinin B (NKB) is a member of the tachykinin family of peptides. Inactivating mutations in the tachykinin 3 or tachykinin 3 receptor gene are associated with pubertal failure and congenital hypogonadotrophic hypogonadism in humans. This suggests that NKB may have a critical role in human reproduction. The effects of NKB administration have not been investigated previously in humans. Aim: The aim of this study was to determine the effects of iv administration of NKB on gonadotrophin secretion in healthy male and female volunteers. Methods: A total of 23 healthy men and 11 healthy women participated in the study. After an initial dose-finding study (study 1), men received a 4-hour infusion of vehicle (gelofusin) followed by a 4-hour infusion of NKB (2.56 or 5.12 nmol/kg/h) (study 2), and an 8-hour infusion of vehicle or NKB during different visits (study 3). Healthy women underwent a dose-finding study consisting of a 3-hour NKB administration during the follicular phase of the menstrual cycle, and the maximum dose of NKB was also tested during the preovulatory and midluteal phases of menstrual cycle (study 4). Results: Mean LH, FSH, and T secretion were not significantly altered during a 90-minute infusion of NKB (0.4–5.12 nmol/kg/h), or a 4-hour infusion of NKB (5.12 nmol/kg/h). No alterations in gonadotrophin secretion or LH pulsatility were observed during an 8-hour infusion of NKB when compared with vehicle. Doses of 0.64–5.12 nmol/kg/h NKB did not significantly alter LH, FSH, or estradiol secretion in healthy women during the follicular phase of the menstrual cycle. Finally, 5.12 nmol/kg/h did not significantly alter reproductive hormone secretion during the preovulatory or midluteal phases of the menstrual cycle. Conclusions: This is the first clinical study of NKB administration. None of the doses of NKB tested were associated with significant alterations in reproductive hormone secretion in healthy male or female volunteers. These novel data add to our understanding of the physiological actions of NKB in human reproduction.
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Anbarasu, M., and D. Udhaya Nandhini. "The Phases of Flower in Sangam Tamil Literature." Shanlax International Journal of Arts, Science and Humanities 8, no. 1 (July 2, 2020): 218–20. http://dx.doi.org/10.34293/sijash.v8i1.3161.
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A flower is the reproductive part of flowering plants. Within the flowering stage of flower had different phases like Arumbu / Bud, Mottu / Tender flower Bud, Mugai / Opening bud, Malar / Flower blossom, Alar / Full-blown flower blossom, Vee / Flower drying and Semmal / Faded flower in Sangam Tamil literature. The Sangam Tamil literature was accompanied of Tamil scholars and poets that, according to phases flower are indicated in Thirukkural, Narrinai, Purananuru, Kuruntokai, Silappatikaram, etc., This review is more useful to researchers for understanding the floral scent properties relation to phases of flower and associated with releasing dynamics for fragrant / scent out of flower.
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Varela, M. L., M. F. Ferreira, R. H. Da Cuña, F. L. Lo Nostro, G. Genovese, and F. J. Meijide. "Dynamics of ovarian maturation throughout the reproductive cycle of the Neotropical cichlid fishCichlasomadimerus(Teleostei, Cichliformes)." Canadian Journal of Zoology 95, no. 7 (July 2017): 485–98. http://dx.doi.org/10.1139/cjz-2016-0198.
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In this study, we analyzed gene expression profiles, plasma steroids concentrations, and gonadal morphology throughout the reproductive cycle of female Cichlasoma dimerus (Heckel, 1840), a monogamous cichlid fish exhibiting social hierarchies. Fish were analyzed at six phases encompassing their annual cycle, namely resting (during the nonreproductive period), prespawning, 30 h post spawning, 4 days post spawning, 10 days post spawning, and subordinate (during the reproductive period). The histological and histomorphometric analysis showed that C. dimerus exhibits asynchronous ovarian development. Similar to resting females, subordinate females showed low gonadosomatic index, reduced expression levels of vitellogenin (vtgAb), zona pellucida (zpB), gonadal aromatase (cyp19a1A), and low concentrations of plasma sex steroids, thus indicating that social intimidation by dominant conspecifics elicited reproductive arrest. In reproductively active females, a direct positive correlation between plasma estradiol, vtgAb expression, percentage of late vitellogenic oocytes, and gonadosomatic index was observed. These parameters were maximal at the prespawning phase, decreased at 30 h post spawning and 4 days post spawning, and then reached a peak at 10 days post spawning. Our results indicate that female C. dimerus become spawning capable after 10 days post spawning, coincidently with the shortest time interval between successive spawns recorded in captivity.
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Su, Qian-Qian, Yi Chen, Jiao Qin, Tong-Liang Wang, De-Hua Wang, and Quan-Sheng Liu. "Effects of mifepristone and quinestrol on the fertility of female Brandt’s voles (Lasiopodomys brandtii) in different reproductive phases." Animal Biology 66, no. 2 (2016): 133–43. http://dx.doi.org/10.1163/15707563-00002492.
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Mifepristone and quinestrol are effective drugs for controlling rodent fertility, but their inhibitory effectiveness during premating, early pregnancy, and late pregnancy is unknown. In this study, six groups of eight female Brandt’s voles (Lasiopodomys brandtii) were administered with mifepristone, quinestrol, or a control for three days during premating, early pregnancy, or late pregnancy. In the mifepristone-treated groups, the premating females bred, whereas the early and late pregnant females did not. The reproductive rate, litter size, average body mass at birth, and survival rate of pups did not significantly differ between the mifepristone-treated premating group and the control group. By contrast, quinestrol treatment completely inhibited fertility during the three reproductive phases. In addition, fertility was not completely restored in the second pairing. The reproductive rates were higher for mifepristone, both during early and late pregnancy, than for quinestrol, but both were lower than the control. Thus, mifepristone and quinestrol both inhibited the fertility of female Brandt’s voles at different reproductive periods. These results suggest that these two sterilants could be delivered during the reproductive season of the target pest animal.
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Knecht, Damian, and Anna Jankowska-Mąkosa. "Endoparasites in Sows and Selected Reproduction Parameters." Acta Veterinaria 70, no. 1 (March 1, 2020): 71–80. http://dx.doi.org/10.2478/acve-2020-0005.
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AbstractThe aim of the study was to analyze infection of sows with endoparasites depending on their physiological phase and length of exploitation, as well as to determine the effects of infection on selected parameters of reproductive performance. 300 fecal samples collected from the same 75 sows in 4 phases of the production cycle (dry sows, low pregnancy, high pregnancy, lactation) were tested in the experiment. Species and gender diversity, prevalence, OPG and EPG were determined in the study. These parameters were compared in terms of the physiological phase and the length of exploitation. Selected parameters of reproductive performance of sows were also examined, which were compared taking into account the length of exploitation and sows infection with individual parasites.The study showed that the entire population was infected with two parasites at all physiological phases: Eimeria spp. (17% prevalence, 2275 OPG) and Ascaris suum (5% prevalence, EPG 79). The presence of parasites from Eimeria genus (prevalence 40%, OPG 2976) in sows exploited for 1 year had a negative effect on some parameters of their reproduction performance. Infected sows, compared to noninfected ones, were characterized by a lower number of live piglets (by 0.21 heads) (p≤0.05), a higher number of stillborn piglets (by 0.21 heads) (p≤0.05), as well as lower daily weight gains of piglets (by 15 g) (p≤0.05), which contributed to their lower weaning body weight (by 0.45 kg) (p≤0.05).
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Bao, AM, RY Liu, EJ van Someren, MA Hofman, YX Cao, and JN Zhou. "Diurnal rhythm of free estradiol during the menstrual cycle." European Journal of Endocrinology 148, no. 2 (February 1, 2003): 227–32. http://dx.doi.org/10.1530/eje.0.1480227.
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OBJECTIVE: To investigate the diurnal rhythm of estrogens in normally cyclic women during reproductive life. DESIGN: Multiple saliva sampling in normally cyclic healthy women during reproductive life at different phases of their menstrual cycles was carried out. METHODS: Salivary estradiol was measured by radioimmunoassay in samples collected every 2 h for 24 h from 15 normally cyclic healthy women during reproductive life during the menstrual phase, the late follicular/peri-ovulation phase, the early to mid luteal phase and the late luteal phase, respectively, of their menstrual cycles. The levels of salivary estradiol were analyzed by means of periodic regression. RESULTS: A daily biological rhythm of free estradiol was found after quantification with a nonlinear periodic regression model. The observed diurnal free estradiol rhythm consists of two major components: an asymmetrically peaked diurnal cycle and ultradian harmonics in the range of 6 to 12 h. The diurnal and ultradian rhythms were remarkably consistent throughout the menstrual cycle in terms of mesor (24 h mean level), peak width and amplitude. There was a tendency for the 24-h rhythm acrophases to converge in the early morning, while the acrophase of the menstrual phase occurred significantly later than in the late follicular/peri-ovulation phase. CONCLUSIONS: The diurnal rhythm of estradiol has a similar complex temporal organization for different menstrual phases. The menstrual cycle mainly modulates the acrophase of the diurnal rhythm.
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Casillas, Fahiel, Miguel Betancourt, Lizbeth Juárez-Rojas, Yvonne Ducolomb, Alma López, Alejandra Ávila-Quintero, Jimena Zamora, Mohammad Mehdi Ommati, and Socorro Retana-Márquez. "Chronic Stress Detrimentally Affects In Vivo Maturation in Rat Oocytes and Oocyte Viability at All Phases of the Estrous Cycle." Animals 11, no. 9 (August 24, 2021): 2478. http://dx.doi.org/10.3390/ani11092478.
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Background: Stress has been considered as one of the causes of decreased reproductive function in women. However, direct evidence of the effect of chronic stress on oocytes depending on estrous cycle phases is limited. Objective: The present study aimed to evaluate the impact of chronic stress on the viability, integrity, and maturation of rat oocytes depending on estrous cycle phases, specifically proestrus, estrus, and diestrus. Methods: For this purpose, adult female rats were stressed daily by cold water immersion (15 °C) for 30 consecutive days. Results: In chronically stressed female rats, irregular estrous cyclicity, increased corticosterone levels, decreased oocyte viability, and an increased percentage of abnormal oocytes were obtained in all the estrous cycle phases, resulting in reduced oocyte maturation during proestrus. Conclusion: Oocyte maturation disturbed by chronic stress is a crucial factor by which chronic stress disrupts female reproduction
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Tucker, Emily K., Megan E. Zurliene, Cory D. Suski, and Romana A. Nowak. "Gonad development and reproductive hormones of invasive silver carp (Hypophthalmichthys molitrix) in the Illinois River." Biology of Reproduction 102, no. 3 (November 11, 2019): 647–59. http://dx.doi.org/10.1093/biolre/ioz207.
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Abstract Reproduction is a major component of an animal’s life history strategy. Species with plasticity in their reproductive biology are likely to be successful as an invasive species, as they can adapt their reproductive effort during various phases of a biological invasion. Silver carp (Hypophthalmicthys molitrix), an invasive cyprinid in North America, display wide variation in reproductive strategies across both their native and introduced ranges, though the specifics of silver carp reproduction in the Illinois River have not been established. We assessed reproductive status using histological and endocrinological methods in silver carp between April and October 2018, with additional histological data from August to October 2017. Here, we show that female silver carp are batch spawners with asynchronous, indeterminate oocyte recruitment, while male silver carp utilize a determinate pattern of spermatogenesis which ceases in the early summer. High plasma testosterone levels in females could be responsible for regulating oocyte development. Our results suggest that silver carp have high spawning activity in the early summer (May–June), but outside of the peak spawning period, female silver carp can maintain spawning-capable status by adjusting rates of gametogenesis and atresia in response to environmental conditions, while males regress their gonads as early as July. The results of this study are compared to reports of silver carp reproduction in other North American rivers as well as in Asia.