The Use of a Brief Synchronization Treatment after Weaning, Combined with Superovulation, Has Moderate Effects on the Gene Expression of Surviving Pig Blastocysts.

The combination of estrus synchronization and superovulation (SS) treatments causes alterations in ovarian and endometrial gene expression patterns, resulting in abnormal follicle and oocyte growth, fertilization, and embryo development. However, the impact of combined SS treatments on the transcriptome of the surviving embryos remains unidentified. In this study, we examined gene expression changes in day 6 blastocysts that survived a brief regimen of synchronization treatment combined with superovulation. The sows were included in one of three groups: SS7 group (n = 6), sows were administered Altrenogest (ALT) 7 days from the day of weaning and superovulated with eCG 24 h after the end of ALT treatment and hCG at the onset of estrus; SO group (n = 6), ALT nontreated sows were superovulated with eCG 24 h postweaning and hCG at the onset of estrus; control group (n = 6), weaned sows displaying natural estrus. Six days after insemination, the sows underwent a surgical intervention for embryo collection. Transcriptome analysis was performed on blastocyst-stage embryos with good morphology. Differentially expressed genes (DEGs) between groups were detected using one-way ANOVA with an un-adjusted p-value < 0.05 and a fold change 1.5. The effect of SO treatment on the number of altered pathways and DEGs within each pathway was minimal. Only four pathways were disrupted comprising only a total of four altered transcripts, which were not related to reproductive functions or embryonic development. On the other hand, the surviving blastocysts subjected to SS7 treatments exhibited moderate gene expression changes in terms of DEGs and fold changes, with seven pathways disrupted containing a total of 10 transcripts affected. In this case, the up-regulation of certain pathways, such as the metabolic pathway, with two up-regulated genes associated with reproductive functions, namely RDH10 and SPTLC2, may suggest suboptimal embryo quality, while the down-regulation of others, such as the glutathione metabolism pathway, with down-regulated genes related to cellular detoxification of reactive oxygen species, namely GSTK1 and GSTO1, could depress the embryos' response to oxidative stress, thereby impairing subsequent embryo development. The gene expression changes observed in the present study in SS7 embryos, along with previous reports indicating SS7 can negatively affect fertilization, embryo production, and reproductive tract gene expression, make its use in embryo transfer programs unrecommendable.

Membrane lipids and maximum lifespan in clownfish.

The longevity-homeoviscous adaptation (LHA) theory of ageing states that lipid composition of cell membranes is linked to metabolic rate and lifespan, which has been widely shown in mammals and birds but not sufficiently in fish. In this study, two species of the genus Amphiprion (Amphiprion percula and Amphiprion clarkii, with estimated maximum lifespan potentials [MLSP] of 30 and 9-16 years, respectively) and the damselfish Chromis viridis (estimated MLSP of 1-2 years) were chosen to test the LHA theory of ageing in a potential model of exceptional longevity. Brain, livers and samples of skeletal muscle were collected for lipid analyses and integral part in the computation of membrane peroxidation indexes (PIn) from phospholipid (PL) fractions and PL fatty acid composition. When only the two Amphiprion species were compared, results pointed to the existence of a negative correlation between membrane PIn value and maximum lifespan, well in line with the predictions from the LHA theory of ageing. Nevertheless, contradictory data were obtained when the two Amphiprion species were compared to the shorter-lived C. viridis. These results along with those obtained in previous studies on fish denote that the magnitude (and sometimes the direction) of the differences observed in membrane lipid composition and peroxidation index with MLSP cannot explain alone the diversity in longevity found among fishes.

A Short-Term Altrenogest Treatment Post-weaning Followed by Superovulation Reduces Pregnancy Rates and Embryo Production Efficiency in Multiparous Sows.

Although embryo transfer (ET) is a biotechnology ready for the swine industry, there are factors to be solved, the availability of embryo donors as one. Multiparous sows as donors ought to be considered since weaning is a natural and efficient method for estrus synchronization. In addition, superovulation treatments at weaning are effective in increasing the efficiency of donor embryo production. However, ET programs typically require more donors than those available from a single weaning, imposing grouping several weanings to establish a batch for ET. Since short-term administration of Altrenogest is effective in delaying estrus after weaning without effects on ovulation and embryo development, we investigated how Altrenogest combined with superovulation would affect reproductive parameters and embryo quality and quantity of weaned multiparous donor sows. The sows were administered Altrenogest from the day of weaning for 14 (SS-14 group; N = 26), 7 (SS-7 group; N = 31) and 4 (SS-4 group; N = 32) days. The sows were superovulated with eCG 24 h after the last administration of Altrenogest and with hCG at the onset of estrus. Sows not treated with Altrenogest that were superovulated with eCG 24 h post-weaning and hCG at the onset of estrus (SC group; N = 37) and sows with natural estrus after weaning (C group; N = 34) were used as control groups. The percentage of sows showing estrus within 10 days was not affected by the treatment, but the interval from Altrenogest withdrawal to estrus was longer (P < 0.05) in the SS groups than the interval from weaning to estrus in the controls. SS treatments increased (P < 0.05) the percentage of sows with ovarian cysts and the development of polycystic ovaries. The pregnancy and the fertilization rates, and the overall embryo production efficiency were also negatively affected by the SS treatments (P < 0.05). Interestingly, almost 70% of the structures classified as unfertilized oocytes or degenerated embryos in sows from the SS groups were immature oocytes. In conclusion, although superovulation of weaned sows was highly efficient, short-term administration of Altrenogest in combination with superovulation had negative effects on most of the reproductive parameters assessed, particularly affecting the overall efficiency of pregnancy and embryo production.

Analysis of the coding sequences of clownfish reveals molecular convergence in the evolution of lifespan.

BACKGROUND: Standard evolutionary theories of aging postulate that reduced extrinsic mortality leads to evolution of longevity. Clownfishes of the genus Amphiprion live in a symbiotic relationship with sea anemones that provide protection from predators. We performed a survey and identified at least two species with a lifespan of over 20 years. Given their small size and ease of captive reproduction, clownfish lend themselves as experimental models of exceptional longevity. To identify genetic correlates of exceptional longevity, we sequenced the transcriptomes of Amphiprion percula and A. clarkii and performed a scan for positively-selected genes (PSGs). RESULTS: The PSGs that we identified in the last common clownfish ancestor were compared with PSGs detected in long-lived mole rats and short-lived killifishes revealing convergent evolution in processes such as mitochondrial biogenesis. Among individual genes, the Mitochondrial Transcription Termination Factor 1 (MTERF1), was positively-selected in all three clades, whereas the Glutathione S-Transferase Kappa 1 (GSTK1) was under positive selection in two independent clades. For the latter, homology modelling strongly suggested that positive selection targeted enzymatically important residues. CONCLUSIONS: These results indicate that specific pathways were recruited in independent lineages evolving an exceptionally extended or shortened lifespan and point to mito-nuclear balance as a key factor.

Age-related changes in mitochondrial membrane composition of Nothobranchius furzeri.: comparison with a longer-living Nothobranchius species.

Membrane compositions, particularly of mitochondria, could be critical factors in the mechanisms of growth and aging, especially during phases of high oxidative stress that result in molecular damage. Changes affecting lipid class or fatty acid (FA) compositions could affect phospholipid (PL) properties and alter mitochondrial function. In the present study, mitochondrial membrane PL compositions were analysed throughout the life-cycle of Nothobranchius furzeri, a species with explosive growth and one of the shortest-lived vertebrates. Mitochondrial PLs showed several changes with age. Proportions of total PLs and PC were reduced while an increase in PS, CL and PE was observed, mainly between the 2.5 and 5 months of fish age, the time during which animals doubled their weight. FA compositions of individual PLs in mitochondria were also significantly affected with age suggesting the existence of increasing damage to mitochondrial lipids during the life-cycle of N. furzeri that could be one of the main contributors to degraded mitochondrial function associated with aging. The peroxidation index values from N. furzeri mitochondrial PLs were significantly lower than those reported in N. rachovii, a species with a twofold longer life span than N. furzeri, which seems to contradict the membrane pacemaker theory of animal metabolism.

The clock is ticking. Ageing of the circadian system: From physiology to cell cycle.

The circadian system is the responsible to organise the internal temporal order in relation to the environment of every process of the organisms producing the circadian rhythms. These rhythms have a fixed phase relationship among them and with the environment in order to optimise the available energy and resources. From a cellular level, circadian rhythms are controlled by genetic positive and negative auto-regulated transcriptional and translational feedback loops, which generate 24h rhythms in mRNA and protein levels of the clock components. It has been described about 10% of the genome is controlled by clock genes, with special relevance, due to its implications, to the cell cycle. Ageing is a deleterious process which affects all the organisms' structures including circadian system. The circadian system's ageing may produce a disorganisation among the circadian rhythms, arrhythmicity and, even, disconnection from the environment, resulting in a detrimental situation to the organism. In addition, some environmental conditions can produce circadian disruption, also called chronodisruption, which may produce many pathologies including accelerated ageing. Finally, some strategies to prevent, palliate or counteract chronodisruption effects have been proposed to enhance the circadian system, also called chronoenhancement. This review tries to gather recent advances in the chronobiology of the ageing process, including cell cycle, neurogenesis process and physiology.

Circadian activity rhythms during the last days of Nothobranchius rachovii's life: a descriptive model of circadian system breakdown.

Several studies have been performed to identify age-related changes in the circadian system (CS) but the impairment of the CS and its chronodisruption at the end of an organism life have not been studied in depth. Aging commonly affects the input pathways into the biological clock or restraints their processing, therefore simplifying the system output, the overt rhythms. The purpose of this work was to do a complete characterization of changes that occurs in the CS in the last stage of a vertebrate organism life and to develop tools able to detect in which moment of the last days of life is the animal, using an overt rhythm, the rest-activity rhythm (RAR). For that, a fish species proposed as model for aging studies, Nothobranchius rachovii, has been used. A progressive and sequential CS breakdown has been described for the last 22 d of life of N. rachovii (∼7% of total life), suffering a general RAR impairment mainly reflected by changes in phase regularity, complexity, amplitude and the ability to stay synchronized to the LD cycle. Also, an equation of days remaining of life, based on the RAR description, has been calculated and proposed as a tool to identify close-to-death individuals which could be subjected to an adequate restoring treatment to enhance the CS function and improve their well-being.

Nothobranchius as a model for aging studies. A review.

In recent decades, the increase in human longevity has made it increasingly important to expand our knowledge on aging. To accomplish this, the use of animal models is essential, with the most common being mouse (phylogenetically similar to humans, and a model with a long life expectancy) and Caenorhabditis elegans (an invertebrate with a short life span, but quite removed from us in evolutionary terms). However, some sort of model is needed to bridge the differences between those mentioned above, achieving a balance between phylogenetic distance and life span. Fish of the genus Nothobranchius were suggested 10 years ago as a possible alternative for the study of the aging process. In the meantime, numerous studies have been conducted at different levels: behavioral (including the study of the rest-activity rhythm), populational, histochemical, biochemical and genetic, among others, with very positive results. This review compiles what we know about Nothobranchius to date, and examines its future prospects as a true alternative to the classic models for studies on aging.

Changes in mitochondrial membrane composition and oxidative status during rapid growth, maturation and aging in zebrafish, Danio rerio.

Considering membranes and membrane components as possible pacemakers of the main processes taking place inside mitochondria, changes in phospholipids or fatty acids could play a central role linking different mechanisms involved in cumulative damage to cell molecules and dysfunction during periods of high stress, such as rapid growth and aging. Changes affecting either lipid class or fatty acid compositions could affect phospholipid and membrane properties and alter mitochondrial function and cell viability. In the present study, mitochondrial oxidative status and mitochondrial membrane phospholipid compositions were analyzed throughout the life-cycle of zebrafish. TBARS content significantly increased in 18-month-old fish while aconitase activity decreased in 24-month-old fish, which have been related with oxidative damage to molecules. Mitochondria-specific superoxide dismutase decreased in 24-month-old animals although this change was not statistically significant. Age affected both mitochondrial phospholipid content and the peroxidation index of most phospholipid classes suggesting that oxidative damage to mitochondrial lipids was occurring.

Age-related changes in mitochondrial membrane composition of Nothobranchius rachovii.

Mitochondrial membrane composition may be a critical factor in the mechanisms of the aging process by influencing the propagation of reactions involved in mitochondrial function during periods of high stress. Changes affecting either lipid class or fatty acid compositions could affect phospholipid properties and alter mitochondrial function and cell viability. In the present study, mitochondrial membrane phospholipid compositions were analyzed throughout the life cycle of Nothobranchius rachovii. Mitochondrial phospholipids showed several changes with age. Proportions of cardiolipin decreased and those of sphingomyelin increased between 11- and 14-month-old fish. Fatty acid compositions of individual phospholipids in mitochondria were also significantly affected with age. These data suggest increasing damage to mitochondrial lipids during the life cycle of N. rachovii that could be one of the main factors related with and contributing to degraded mitochondrial function associated with the aging process.

Rest-activity circadian rhythms in aged Nothobranchius korthausae. The effects of melatonin.

Adult (48-week-old) and senescent (72-week-old) individually-kept Nothobranchius korthausae were used as experimental subjects to characterise circadian system (CS) function and age-related changes in senescent fish. This species was specifically chosen because it has already shown potential for use as a model system in gerontological studies. The rest-activity rhythm (RAR) in fish can be easily monitored and used to characterise the state of the CS, and it has also been proposed as a reliable model to study sleep-like periods in fish. As they aged, N. korthausae experienced a significant decrease in total daily activity and a progressive impairment of the RAR, accompanied by changes in the regularity, fragmentation and amplitude of the rhythm. The ability of the CS to oscillate autonomously when the two main synchronizers, photoperiod and feeding time, were absent (continuous darkness and random feeding), was also impaired with age, as the capacity to re-synchronise to the light-dark (LD) cycle declined. Melatonin treatment improved the regularity, fragmentation and amplitude of the RAR in senescent fish, and it also improved sleep efficiency. In conclusion, N. korthausae represents a viable model for studying the aging of the circadian system and the restorative effect of chronobiotic substances, such as melatonin.

[Aging of the circadian system]. / Envejecimiento del sistema circadiano.

Ageing affects all organic structures and processes, including the circadian system and its principal sign, the biological rhythms. The circadian system temporarily organizes the living organisms. It is made up of structures receiving information from the external environment (that synchronize the circadian clock), the central circadian pacemaker and the peripheral clocks that depends on it, and several outputs that are the overt rhythms. Ageing produces losses in function of all these three components: receptors (the eye in its capacity to transmit the more active light information to the circadian system), the central pacemaker (due to alterations in neuronal function) and the outputs. This leads to the alteration of overt rhythms, with losses in the phase relationship between them, a reduction in amplitude, an increase in fragmentation and an advancement of its phase.