Effects of Aging and Moderate Calorie Restriction on the Reproductive Axis of the Male Rhesus Macaque (Macaca mulatta)

Calorie restriction (CR) has been established as the only non-genetic method of altering longevity and attenuating biological changes associated with aging. This nutritional paradigm has been effective in nematodes, flies, rodents, dogs and possibly non-human primates. Its long history notwithstanding, little is known regarding the exact mechanism(s) of CR action or its potential impact on the hypothalamic-pituitary-gonadal (HPG) axis. The objectives of this project were to: 1) analyze neuroendocrine changes to the HPG axis that occur with aging and 2) evaluate the effects of moderate CR on reproductive function in male rhesus macaques. Pituitary gene expression profiling, semi-quantitative RT-PCR (sqRT-PCR) and immunohistochemistry showed circadian clock mechanism components present in three age categories of macaques, demonstrated age differences in expression for Per2, indicated differential expression of Per2 and Bmal1 at opposing time points and revealed daily rhythmic expression of REV-ERBα protein. These data indicate the ability of the macaque pituitary to express core-clock genes, their protein products, and to do so in a 24-hour rhythm. Young Adult CON and CR pituitary gene expression profiles detected potential differential expression in <150 probesets. A decline in>TSHR and CGA was detected in CR macaques as measured by sqRT-PCR. Other genes investigated showed no diet-induced changes. Young Adult CON and CR testicular gene expression profiles detected potential differential expression in <300 probesets although mRNA expression was not altered based on sqRT-PCR and real-time RT-PCR. Age-related>and/or diet-induced changes in HSD17β3, INSL3, CSNK1E and CGA were observed in a separate experiment with CGA in Old Adult CR subjects returning to youthful levels. Semen samples were collected from Young Adult CON and CR macaques. Normal spermiogram measures, ZP-binding, AR assay and SCSA^® were conducted and indicated no differences between CON and CR-treated animals. Both groups exhibited similar daily testosterone profiles with no differences in mean or maximum levels; however, daily minimum testosterone levels were lower in CON animals. It appears that moderate CR had limited impact on neuroendocrine or reproductive function in male rhesus macaques based on our selected endpoints. Thus, advantageous CR health benefits can be achieved without obvious negative consequences to the HPG axis.

Epistasis among Drosophila persimilis factors conferring hybrid male sterility with D. pseudoobscura bogotana.

The Bateson-Dobzhansky-Muller model posits that hybrid incompatibilities result from genetic changes that accumulate during population divergence. Indeed, much effort in recent years has been devoted to identifying genes associated with hybrid incompatibilities, often with limited success, suggesting that hybrid sterility and inviability are frequently caused by complex interactions between multiple loci and not by single or a small number of gene pairs. Our previous study showed that the nature of epistasis between sterility-conferring QTL in the Drosophila persimilis-D. pseudoobscura bogotana species pair is highly specific. Here, we further dissect one of the three QTL underlying hybrid male sterility between these species and provide evidence for multiple factors within this QTL. This result indicates that the number of loci thought to contribute to hybrid dysfunction may have been underestimated, and we discuss how linkage and complex epistasis may be characteristic of the genetics of hybrid incompatibilities. We further pinpoint the location of one locus that confers hybrid male sterility when homozygous, dubbed "mule-like", to roughly 250 kilobases.

Group takeover by a natal male howling monkey (Alouatta palliata) and associated disappearance and injuries of immatures

As part of a long-term study on howling monkey behavior and social dynamics, a known natal male was observed taking over his group from his putative sire. Due to the accidental death of one of the adult males, this natal male had matured in a one-male group and had never observed juvenile male emigration nor adult male immigration and associated behaviors. Nevertheless, the behaviors associated with the takeover were indistinguishable from those of an immigrant male, including disappearance of immatures, one of whom was found with extensive injuries. While it cannot be said that the natal male inherited these behaviors from his presumed father, it can be said that he exhibited species-typical behaviors associated with male takeover in the absence of observational learning. © 1994 Japan Monkey Centre.

Comparison of dynamic balance in adolescent male soccer players from rwanda and the United States.

PURPOSE/BACKGROUND: Dynamic balance is an important component of motor skill development. Poor dynamic balance has previously been associated with sport related injury. However, the vast majority of dynamic balance studies as they relate to sport injury have occurred in developed North American or European countries. Thus, the purpose of this study was to compare dynamic balance in adolescent male soccer players from Rwanda to a matched group from the United States. METHODS: Twenty-six adolescent male soccer players from Rwanda and 26 age- and gender-matched control subjects from the United States were screened using the Lower Quarter Y Balance Test during their pre-participation physical. Reach asymmetry (cm) between limbs was examined for all reach directions. In addition, reach distance in each direction (normalized to limb length, %LL) and the composite reach score (also normalized to %LL) were examined. Dependent samples t-tests were performed with significant differences identified at p<0.05. RESULTS: Twenty-six male soccer players from Rwanda (R) were matched to twenty-six male soccer players from the United States (US). The Rwandan soccer players performed better in the anterior (R: 83.9 ± 3.2 %LL; US: 76.5 ± 6.6 %LL, p<0.01), posterolateral (R: 114.4 ± 8.3 %LL ; US: 106.5 ± 8.2 %LL, p<0.01) and composite (R: 105.6 ± 1.3 %LL; US: 97.8 ± 6.2 %LL, p<0.01) reach scores. No significant differences between groups were observed for reach asymmetry. CONCLUSIONS: Adolescent soccer players from Rwanda exhibit superior performance on a standardized dynamic balance test as comparison to similar athletes from the United States. The examination of movement abilities of athletes from countries of various origins may allow for a greater understanding of the range of true normative values for dynamic balance. LEVELS OF EVIDENCE: 3b.

Sexually coercive male chimpanzees sire more offspring.

In sexually reproducing animals, male and female reproductive strategies often conflict. In some species, males use aggression to overcome female choice, but debate persists over the extent to which this strategy is successful. Previous studies of male aggression toward females among wild chimpanzees have yielded contradictory results about the relationship between aggression and mating behavior. Critically, however, copulation frequency in primates is not always predictive of reproductive success. We analyzed a 17-year sample of behavioral and genetic data from the Kasekela chimpanzee (Pan troglodytes schweinfurthii) community in Gombe National Park, Tanzania, to test the hypothesis that male aggression toward females increases male reproductive success. We examined the effect of male aggression toward females during ovarian cycling, including periods when the females were sexually receptive (swollen) and periods when they were not. We found that, after controlling for confounding factors, male aggression during a female's swollen periods was positively correlated with copulation frequency. However, aggression toward swollen females was not predictive of paternity. Instead, aggression by high-ranking males toward females during their nonswollen periods was positively associated with likelihood of paternity. This indicates that long-term patterns of intimidation allow high-ranking males to increase their reproductive success, supporting the sexual coercion hypothesis. To our knowledge, this is the first study to present genetic evidence of sexual coercion as an adaptive strategy in a social mammal.

Baby on board: olfactory cues indicate pregnancy and fetal sex in a non-human primate.

Olfactory cues play an integral, albeit underappreciated, role in mediating vertebrate social and reproductive behaviour. These cues fluctuate with the signaller's hormonal condition, coincident with and informative about relevant aspects of its reproductive state, such as pubertal onset, change in season and, in females, timing of ovulation. Although pregnancy dramatically alters a female's endocrine profiles, which can be further influenced by fetal sex, the relationship between gestation and olfactory cues is poorly understood. We therefore examined the effects of pregnancy and fetal sex on volatile genital secretions in the ring-tailed lemur (Lemur catta), a strepsirrhine primate possessing complex olfactory mechanisms of reproductive signalling. While pregnant, dams altered and dampened their expression of volatile chemicals, with compound richness being particularly reduced in dams bearing sons. These changes were comparable in magnitude with other, published chemical differences among lemurs that are salient to conspecifics. Such olfactory 'signatures' of pregnancy may help guide social interactions, potentially promoting mother-infant recognition, reducing intragroup conflict or counteracting behavioural mechanisms of paternity confusion; cues that also advertise fetal sex may additionally facilitate differential sex allocation.

Male mice song syntax depends on social contexts and influences female preferences.

In 2005, Holy and Guo advanced the idea that male mice produce ultrasonic vocalizations (USV) with some features similar to courtship songs of songbirds. Since then, studies showed that male mice emit USV songs in different contexts (sexual and other) and possess a multisyllabic repertoire. Debate still exists for and against plasticity in their vocalizations. But the use of a multisyllabic repertoire can increase potential flexibility and information, in how elements are organized and recombined, namely syntax. In many bird species, modulating song syntax has ethological relevance for sexual behavior and mate preferences. In this study we exposed adult male mice to different social contexts and developed a new approach of analyzing their USVs based on songbird syntax analysis. We found that male mice modify their syntax, including specific sequences, length of sequence, repertoire composition, and spectral features, according to stimulus and social context. Males emit longer and simpler syllables and sequences when singing to females, but more complex syllables and sequences in response to fresh female urine. Playback experiments show that the females prefer the complex songs over the simpler ones. We propose the complex songs are to lure females in, whereas the directed simpler sequences are used for direct courtship. These results suggest that although mice have a much more limited ability of song modification, they could still be used as animal models for understanding some vocal communication features that songbirds are used for.

Will ICSI overthrow IVF in all cases of male infertility ?

info:eu-repo/semantics/nonPublished