Major Nutritional Metabolic Alterations Influencing the Reproductive System of Postpartum Dairy Cows

Early successful conception of postpartum dairy cows is crucial in determining the optimum reproductive efficiency and profitability in modern dairy farming. Due to the inherent high production potential of modern dairy cows, the extra stress burden of peri-parturient events, and associated endocrine and metabolic changes causes negative energy balance (NEBAL) in postpartum cows. The occurrence of NEBAL is associated with excessive fat mobilization in the form of non-esterified fatty acids (NEFAs). The phenomenon of NEFA mobilization furthers with occurrence of ketosis and fatty liver in postpartum dairy cows. High NEFAs and ketones are negatively associated with health and reproductive processes. An additional burden of hypocalcemia, ruminal acidosis, and high protein metabolism in postpartum cows presents further consequences for health and reproductive performance of postpartum dairy cows. This review intends to comprehend these major nutritional metabolic alterations, their mechanisms of influence on the reproduction process, and relevant mitigation strategies.

Climate Change on Fertility and Reproductive Processes of Female Livestock

The effects of climate change continues to be a growing modern-day challenge. Climate change-induced heat stress disrupts reproductive and fertility systems in livestock. In males, it modifies the physiology of the spermatogenic cycle resulting to poor quality semen and high prevalence of secondary sperm defects. In female livestock, heat stress decreases the production of gonadotrophins, results to hormonal imbalance, decreases the quality of oocytes, and lengthens the oestrous period leading to infertility. These effects can be reversed through genetic modifications, nutritive supplementation, physical cooling mechanisms, and hormonal therapies. The successful implementation of the ameliorative strategies is pegged on improved research and their combined administration. Ultimately, climate change mitigation and adaptation are indispensable to overcome fertility problems in livestock among other environmental effects of the climate variations.

Screening for Odorant Receptor Genes Expressed in Aedes Aegypti Involved in Blood-Feeding and Oviposition Behaviors

Background: Aedes aegypti is one of the most important vector worldwide, and its survival and reproductive processes depend heavily on the olfactory system. In this study, the expression levels of all odorant receptor (OR) genes of Ae. aegypti were explored in different physiological periods to identify olfactory genes that may be associated with mosquito blood sucking and searching for oviposition sites.Methods: Four groups, consisting of Ae. aegypti males (M), pre-blood-feeding females (F), post-blood-feeding females (B) and post-oviposition females (O), were established. A total of 114 pairs of primer targeting all OR genes were designed based on the whole genome of Ae. aegypti. The expression of OR genes was evaluated by real-time fluorescence quantitative PCR for relative quantification and the comparison of differences between groups.Results: A total of 53 differentially expressed OR genes were identified between males and females in Ae. aegypti antennae. And 8, 5 and 13 differentially expressed OR genes were identified before versus after blood feeding, before versus after oviposition and post-blood-feeding versus post-oviposition, respectively. Meanwhile, 16 OR genes were significantly differentially expressed in multiple physiological periods of mosquitoes.Conclusions: A large number of ORs with significant intergroup differences and high expression levels were screened in this study, including OR75, OR88, OR110 and OR115 and so on. Some of these genes are reported for the first time, providing possible targets for the development of mosquito control pathways based on the olfactory system.

Suplementación de vitamina D en embarazadas y en mujeres con patologías ginecológicas

Apart from the well-known effects of vitamin D in maintaining calcium homeostasis and promoting bone mineralization, there is evidence to suggest that it modulates reproductive processes. About 70% adults have vitamin D deficiencies and there is a gap between recommended dietary intakes and deficient supply in general population. Observational studies show that vitamin D deficiency is a risk marker for reducing fertility and resulting adverse pregnancy. Evidence suggests that it could have beneficial effects on metabolic, hormonal and cellular parameters of polycystic ovarian syndrome, uterine myomatosis and endometriosis, while it seems to be associated with improvements in outcome of in vitro fertilization. The objective of this review was to evaluate the data of current literature on the role of vitamin D supplementation in pregnant women and in women with gynecological pathologies. Keywords: Vitamin D, Supplementation, Pregnancy, Endometriosis, Uterine myomatosis, Infertility.

Sperm-Guiding Unconventional Prostaglandins in C. elegans: Synthesis and Signaling

Prostaglandins comprise a family of lipid signaling molecules derived from polyunsaturated fatty acids and are involved in a wide array of biological processes, including fertilization. Prostaglandin-endoperoxide synthase (a.k.a. cyclooxygenase or Cox) initiates prostaglandin synthesis from 20-carbon polyunsaturated fatty acids, such as arachidonic acid. Oocytes of Caenorhabditis elegans (C. elegans) have been shown to secrete sperm-guidance cues prostaglandins, independent of Cox enzymes. Both prostaglandin synthesis and signal transduction in C. elegans are environmentally modulated pathways that regulate sperm guidance to the fertilization site. Environmental factors such as food triggers insulin and TGF-β secretion and their levels regulate tissue-specific prostaglandin synthesis in C. elegans. This novel PG pathway is abundant in mouse and human ovarian follicular fluid, where their functions, mechanism of synthesis and pathways remain to be established. Given the importance of prostaglandins in reproductive processes, a better understanding of how diets and other environmental factors influence their synthesis and function may lead to new strategies towards improving fertility in mammals.

Leptin and Beyond: Actors in Cancer

Leptin is a 16-kDa multifunctional, neuroendocrine peptide hormone secreted by adipocytes in proportion to total adipose tissue mass, known to control food intake, energy homeostasis, immune response, and reproductive processes [...]

Putative biotic drivers of plant phenology :with special reference to pathogens and deciduousness

Plant phenology is manifested in the seasonal timing of vegetative and reproductive processes, but also has ontogenetic aspects. The adaptive basis of seasonal phenology has been considered mainly in terms of climatic drivers. However, some biotic factors as likely evolutionary influences on plants’ phenology appear to have been under-researched. Several specific cases of putative biotic factors driving plant phenology are outlined, involving both herbivores and pathogens. These illustrate the diversity of likely interactions rather than any systematic coverage or review. Emphasis is on woody perennials, in which phenology is often most multi-faceted and complicated by the ontogenetic aspect. The complete seasonal leaf fall that characterises deciduous plants may be a very important defence against some pathogens. Whether biotic influences drive acquisition or long-term persistence of deciduousness is considered. In one case; of leaf rusts in poplars, countervailing influences of the rusts and climate suggest persistence. Often, however, biotic and environmental influences likely reinforce each other. The timing and duration of shoot flushing may in at least some cases contribute to defences against herbivores, largely through brief periods of ‘predator satiation’ when plant tissues have highest food value. Wide re-examination of plant phenology, accommodating the roles of biotic factors and their interplays with environments as additional adaptive drivers, is advocated, towards developing and applying hypotheses that are observationally or experimentally testable.

Differential regulation of flower transpiration during abiotic stress in plants

Heat waves, occurring during droughts, can have a devastating impact on yield, especially if they happen during the flowering and seed set stages of the crop cycle. Global warming and climate change are driving an alarming increase in the frequency and intensity of combined drought and heat stress episodes, critically threatening global food security. Previous studies revealed that during a combination of drought and heat stress stomata on leaves of many plants are closed, preventing cooling by transpiration. Because high temperature is detrimental to reproductive processes, essential for plant yield, we measured the inner temperature, transpiration, and sepal stomatal aperture of closed soybean flowers, developing on plants subjected to a combination of drought and heat stress. Here, we report that during a combination of drought and heat stress soybean plants prioritize transpiration through flowers over transpiration through leaves by opening their flower stomata, while keeping their leaf stomata closed. This acclimation strategy, termed differential transpiration, lowers flower inner temperature by about 2-3oC, protecting reproductive processes at the expense of vegetative tissues. Manipulating stomatal regulation, stomatal size and/or stomatal density of flowers could therefore serve as a viable strategy to enhance the yield of different crops and mitigate some of the current and future impacts of global warming and climate change on agriculture.

On the reproductive mechanism of Gram-negative protocells

Protocells are thought to have existed on early Earth before the origin of prokaryotes. These primitive cells are believed to have carried out processes like replication solely based on the physicochemical properties of their cell constituents. Despite considerable efforts, replication of a living cell-driven entirely by laws of physics and chemistry has never been achieved. To test this hypothesis, we transformed extant bacteria into sacks of cytoplasm, incapable of regulating either their morphology or reproductive processes. We then exposed these proxy-protocells (bacterial protoplasts) to presumed Archaean Eon environmental conditions to understand if or how these cells reproduce. Contrary to the current presumption that bacterial protoplasts reproduce in a haphazard manner, under our experimental conditions they reproduced via a multi-stage reproductive cycle, resulting in viable daughter cells. Our observations suggest that this mechanism of reproduction could in fact be well explained from a biophysical perspective. Based on our observations we argue that this method of reproduction is better suited for the environmental conditions of early Earth.

On the reproductive mechanisms of Gram-positive protocells

Bacterial protoplasts are believed to reproduce in a haphazard manner. Their unregulated method of reproduction is considered the simplest of all known forms of cell replication. In the present study, we attempted to understand the evolutionary significance and physiochemical mechanisms behind this process. Here we transformed a Gram-positive bacterium into sack of cytoplasm, incapable of regulating either its morphology or reproductive processes. As such primitive (proto)cells devoid of molecular biological processes could have been native to early Earth, we grew these cells under environmental conditions of early Earth. We then monitored these cells at regular intervals to understand if they can grow and reproduce under these conditions. In our incubations, cells exhibited a multi-stage reproductive cycle resulting in viable daughter cells. What was previously thought to be a chaotic reproductive process, could in fact be well explained from a physicochemical perspective. Both morphology and reproductive process of these cells were determined by chemical and self-assembling properties of their cell constituents rather than the information encoded in their genome. Despite its haphazard appearance, we propose that the reproductive process of bacterial protoplasts is better optimized for environmental conditions of early Earth and could be reminiscent of protocell reproductive processes.Abstract Figure