Read by QxMD icon Read

Sexual maturation

M Jambui, C F Honaker, P B Siegel
Reported here are correlated responses for reproductive traits to long-term divergent selection (54 generations) for 8-week body weight (BW8). Comparisons involved both selected and relaxed lines. Traits measured were age at first egg (AFE), body weight at first egg (WFE), and ratio of body weight and age at first egg (WAFE). Although sexual maturity was delayed in the selected lines, the effect was more pronounced in the low than high selected and relaxed lines. Selection for low BW resulted in decreases in WFE and WAFE...
September 1, 2017: Poultry Science
Jeanne Tonnabel, Patrice David, John R Pannell
The differential plasticity hypothesis suggests that sexual dimorphism in dioecious plants could evolve in response to sex-specific resource requirements for reproduction (i.e., high carbon requirements for ovules and high nitrogen demands for pollen). When resources become limiting during growth, males and females should, therefore, adjust their allocation to resource-harvesting organs differently. To investigate the potential for plants to respond to resource limitation late in life and to test the differential plasticity hypothesis, we grew male and female individuals of the annual wind-pollinated plant Mercurialis annua in a common garden...
October 17, 2017: Oecologia
Gen L Takei, Masakatsu Fujinoki, Kaoru Yoshida, Sumio Ishijima
STUDY QUESTION: What is the role of metachronal and synchronous sliding in sperm flagellar motility? SUMMARY ANSWER: Both metachronal and oscillatory synchronous sliding are essential for sperm flagellar motility, while the change in mode of synchronous sliding between the non-oscillatory synchronous sliding of a specific pair of the doublet microtubules and the oscillatory synchronous sliding between most pairs of doublet microtubules modulates the sperm flagellar motility...
October 11, 2017: Molecular Human Reproduction
Manuel Pool-Chalé, Ivón Ramírez-Morillo, Germán Carnevali Fernández-Concha, Claudia T Hornung-Leoni
Individuals of Aechmea bracteata show inflorescences with red scape bracts and odorless, yellow, tubular, diurnal flowers, with closely-arranged sexual organs, producing a large amount of fruits. In order to investigate the reproductive system of this species, a suite of characters were assessed: phenology, floral morphology and biology, nectar production dynamics, and fruit and seed production and germination, as a result of controlled pollination crosses. The study was conducted during two flowering seasons in wild populations in Yucatán, Mexico...
October 13, 2017: Plant Biology
Renee A Lopez, Karen S Renzaglia
Unlike most plant cell walls, the five consecutive walls laid down during spermatogenesis in the model fern Ceratopteris contain sparse cellulose, lack pectin and are enriched with callose and hemicelluloses. Seed-free plants like bryophytes and pteridophytes produce swimming male gametes for sexual reproduction. During spermatogenesis, unique walls are formed that are essential to the appropriate development and maturation of the motile gametes. Other than the detection of callose and general wall polysaccharides in scattered groups, little is known about the sequence of wall formation and the composition of these walls during sperm cell differentiation in plants that produce swimming sperm...
October 13, 2017: Planta
Yu Sun Kang, Dong-Yoon Yoo, In Hyuk Chung, Eun-Gyong Yoo
PURPOSE: Pubertal gonadotropin secretion shows circadian pattern and the luteinizing hormone (LH) levels tend to rise in later stages of puberty in girls. We studied the usefulness of basal LH in the evaluation of central precocious puberty with emphasis on the influence of sampling time. METHODS: Medical records of 334 girls that underwent gonadotropin-releasing hormone stimulation test (GnRHST) were reviewed. Auxological and laboratory data were compared between those with early morning (EM, before 10 AM) and late morning/afternoon (LM/A, after 10 AM) basal samples...
September 2017: Annals of Pediatric Endocrinology & Metabolism
Julien M D Legrand, Robin M Hobbs
Mammalian spermatogenesis is a tightly coordinated process that gives rise to mature spermatozoa capable of fertilising an ovum during sexual reproduction. A population of stem and progenitor cells known as undifferentiated spermatogonia enables continual spermatogenesis throughout life. A complex transcriptional network that balances self-renewal of spermatogonia with their timely differentiation in order to maintain constant fertility regulates this process. Importantly, post-transcriptional regulation of gene expression plays a critical role in spermatogenesis, necessitated by the profound genetic and morphological changes that occur during meiosis and sperm maturation...
October 9, 2017: Seminars in Cell & Developmental Biology
Ayoub Baali, Hajar Bourassi, Samira Falah, Wahbi Abderrazik, Khalid Manchih, Khadija Amenzoui, Ahmed Yahyaoui
BACKGROUND AND OBJECTIVE: Sardinella sp. has gained much attention lately because of its biomass increase, which might be the result of climatic changes occurring across the Atlantic sea. Little information is known about reproduction of these species particularly in the Moroccan Atlantic area. The objective of the this study was to explore some aspects of the reproductive biology of Sardinella in the South of Atlantic Moroccan coast. MATERIALS AND METHODS: Monthly samples were collected during the period between February, 2015 and January, 2016 in the area between Cape Boujdor and Cape Blanc...
2017: Pakistan Journal of Biological Sciences: PJBS
Siti Nor Fatihah, Harman Muhd-Farouk, Adnan Amin-Safwan, Hairul Hafiz Mahsol, Mhd Ikhwanuddin
BACKGROUND AND OBJECTIVE: Mud spiny lobsters, Panulirus polyphagus (P. polyphagus) are one of the most important fisheries resources now-a-days due to quality that it's possessed. However, there is still lack of in-depth study about this species mainly on males testicular characteristics and sexual maturity size. Therefore, the present study was carried out to investigate the histological characteristics on the testes and sexual maturity sizes of mud spiny lobster, Panulirus polyphagus...
2017: Pakistan Journal of Biological Sciences: PJBS
Jan Werner, Eva Maria Griebeler
Endothermy and its evolution are still an unresolved issue. Here, we present a model which transforms an ectothermic amniote (ancestor) into a derived amniote (descendant) showing many characteristics seen in extant endothermic birds and mammals. Consistent with the fossil record within the ancestral lineages of birds and mammals, the model assumes that mutations in genes which get active during ontogeny and affect body growth resulted in a reduced asymptotic body size and an early growth stop of the descendant...
October 11, 2017: Die Naturwissenschaften
Etsuko Katsumata, Sukanya Jaroenporn, Yoko Ueda, Kazutoshi Arai, Hiroshi Katsumata, Gen Watanabe, Kazuyoshi Taya
To reveal the reproductive biology in male bottlenose dolphins (Tursiops truncatus), circulating gonadotropins (follicle stimulating hormone [FSH] and luteinizing hormone [LH]) and testicular hormones (testosterone and inhibin) were monitored for 8 -12 years in 2 captive bottlenose dolphins (Mars and Regulus). During the study period, Mars was undergoing sexual maturation, whereas Regulus was already mature at the beginning of the study. Assuming that Mars had reached sexual maturity when the significant increase in circulating testosterone levels was observed, serum concentration of inhibin was higher in the sexually immature stage than in the mature stage, whereas the serum concentration of FSH was higher in the sexually mature stage than in the immature stage...
October 7, 2017: Journal of Veterinary Medical Science
Elizabeth M Parzych, Kazutoyo Miura, Aarti Ramanathan, Carole A Long, James M Burns
Challenges with the production and suboptimal immunogenicity of malaria vaccine candidates have slowed the development of a Plasmodium falciparum multi-antigen vaccine. Attempting to resolve these issues, we focused on the use of the highly immunogenic merozoite surface protein 8 (MSP8) as a vaccine carrier protein. Previously, we showed that genetic fusion of the C-terminal 19 kDa fragment of merozoite surface protein 1 (MSP119) to PfMSP8 facilitated antigen production, folding and induction of neutralizing antibodies to conformational B cell epitopes of MSP119 Here, using the PfMSP1/8 construct, we further optimized the rPfMSP8 carrier by introduction of two cysteine to serine substitutions (CΔS) to improve the yield of monomeric product...
October 9, 2017: Infection and Immunity
Janina Stauffer, Bineet Panda, Petteri Ilmonen
Antioxidants and telomere length are potential biomarkers for individuals' exposure and ability to cope with environmental stressors. However, intraspecific variations in antioxidant alterations due to natural, life cycle related stress, have been rarely estimated. We investigated those changes in wild-derived house mice in a longitudinal study with natural sibling competition as a stressor. Blood was used for telomere length measurements at 8-weeks age and for several selected antioxidants at 8-weeks and 6-months age...
October 6, 2017: Mechanisms of Ageing and Development
Kristen A Kellock, Adrian P Moore, Robert B Bringolf
Nitrate is a ubiquitous aquatic pollutant that is commonly associated with eutrophication and dead zones in estuaries around the world. At high concentrations nitrate is toxic to aquatic life but at environmental concentrations it has also been purported as an endocrine disruptor in fish. To investigate the potential for nitrate to cause endocrine disruption in fish, we conducted a lifecycle study with fathead minnows (Pimephales promelas) exposed to nitrate (0, 11.3, and 56.5 mg/L (total nitrate-nitrogen (NO3-N)) from <24 h post hatch to sexual maturity (209 days)...
October 3, 2017: Environmental Pollution
Alessandra Guidi, Cristiana Lalli, Roberto Gimmelli, Emanuela Nizi, Matteo Andreini, Nadia Gennari, Fulvio Saccoccia, Steven Harper, Alberto Bresciani, Giovina Ruberti
Schistosomiasis, one of the most prevalent neglected parasitic diseases affecting humans and animals, is caused by the Platyhelminthes of the genus Schistosoma. Schistosomes are the only trematodes to have evolved sexual dimorphism and the constant pairing with a male is essential for the sexual maturation of the female. Pairing is required for the full development of the two major female organs, ovary and vitellarium that are involved in the production of different cell types such as oocytes and vitellocytes, which represent the core elements of the whole egg machinery...
October 2017: PLoS Neglected Tropical Diseases
Molly Parkyn Schneider, Boyin Liu, Philipp Glock, Annika Suttie, Emma McHugh, Dean Andrew, Steven Batinovic, Nicholas Williamson, Eric Hanssen, Paul McMillan, Marion Hliscs, Leann Tilley, Matthew W A Dixon
Transmission of malaria parasites relies on the formation of a specialized blood form called the gametocyte. Gametocytes of the human pathogen, Plasmodium falciparum, adopt a crescent shape. Their dramatic morphogenesis is driven by the assembly of a network of microtubules and an underpinning inner membrane complex (IMC). Using super-resolution optical and electron microscopies we define the ultrastructure of the IMC at different stages of gametocyte development. We characterize two new proteins of the gametocyte IMC, called PhIL1 and PIP1...
October 2017: PLoS Pathogens
Anatolii Romaniuk, Mykola Lyndin, Yulia Lуndіna, Vladyslav Sikora, Natalia Hrintsova, Olena Timakova, Olena Gudymenko, Oksana Gladchenko
OBJECTIVE: The aim of our work was to study the blood parameters and bone marrow morphological changes in rats exposed to increased amounts of heavy metal salts and the effect of vitamin E. MATERIAL AND METHOD: Investigation of bone marrow structural features and blood parameters was performed in sexually mature Wistar male rats (n=84). RESULTS: Exposure to increased amounts of heavy metal salts led to the inhibition of erythropoiesis and leukopoiesis, as well as a synchronized increase in the number of megakaryocytes which was clearly reflected in the blood: the number of erythrocytes, leukocytes and Hb decreased, and the number of platelets increased...
October 6, 2017: Türk Patoloji Dergisi
Yongjuan Guan, Graeme B Martin
This review explores the cellular and molecular mechanisms that regulate spermatogenesis in the post-pubertal testis that is regressing in response to mild undernutrition, using the sexually mature male sheep as a model. Testis regression leads to reductions in daily sperm production and in the quality of ejaculated spermatozoa (poorer movement, DNA damage). There is also a reduction in spermatogenic efficiency that appears to be caused, at least partially, by increases in germ cell apoptosis. Sertoli cell number does not change with testis regression, although about 1% of Sertoli cells do appear to retain proliferative ability after puberty...
November 2017: Reproduction: the Official Journal of the Society for the Study of Fertility
Takeshi Ohkubo
In the majority of vertebrates, survival of offspring to sexual maturation is important for increasing population size, and parental investment in the young is important for reproductive success. Consequently, parental care is critical for the survival of offspring in many species, and many vertebrates have adapted this behavior to their social and ecological environments. Parental care is defined as any behavior that is performed in association with one's offspring (Rosenblatt, Mayer, Siegel. Maternal behavior among nonprimate mammals...
2017: Advances in Experimental Medicine and Biology
Yasuko Tobari, Yoshimi Sato, Kazuo Okanoya
Social interactions rapidly modulate circulating hormone levels and behavioral patterns in most male animals. In male birds, sexual interaction or visual exposure to a conspecific female usually causes an increase in the levels of peripheral reproductive hormones, such as gonadotropins and androgens. Although the perception of a female presence is processed in the brain and peripheral hormonal levels are regulated by the hypothalamus-pituitary-gonadal (HPG) axis, the specific neural circuitry and neurochemical systems that translate social signals into reproductive physiology in male birds were not well understood until 2008...
2017: Advances in Experimental Medicine and Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"