Postcopulatory sexual selection (PCSS), comprised of sperm competition and cryptic female choice, has emerged as a widespread evolutionary force among polyandrous animals. There is abundant evidence that PCSS can shape the evolution of sperm. However, sperm are not the whole story: they are accompanied by seminal fluid substances that play many roles, including influencing PCSS. Foremost among seminal fluid models is Drosophila melanogaster , which displays ubiquitous polyandry, and exhibits intraspecific variation in a number of seminal fluid proteins (Sfps) that appear to modulate paternity share. Here, we first consolidate current information on the identities of D. melanogaster Sfps. Comparing between D. melanogaster and human seminal proteomes, we find evidence of similarities between many protein classes and individual proteins, including some D. melanogaster Sfp genes linked to PCSS, suggesting evolutionary conservation of broad-scale functions. We then review experimental evidence for the functions of D. melanogaster Sfps in PCSS and sexual conflict. We identify gaps in our current knowledge and areas for future research, including an enhanced identification of PCSS-related Sfps, their interactions with rival sperm and with females, the role of qualitative changes in Sfps and mechanisms of ejaculate tailoring. This article is part of the theme issue ‘Fifty years of sperm competition’.
Objective: To review the physiology of lactate production and metabolism, the causes of lactic acidosis, and the current applications of lactate monitoring in humans and animals. Data sources: Human and veterinary studies. Summary: Lactate production is the result of anaerobic metabolism. Tissue hypoxia due to hypoperfusion is the most common cause of lactic acidosis. Studies in critically ill humans have shown that serial lactate monitoring can be used to assess the severity of illness and response to therapy. Several veterinary studies have also shown lactate as a useful tool to assess severity of illness. Conclusions: Lactate measurement in critically ill veterinary patients is practical and can provide information to assess severity of illness. Further veterinary studies are needed to establish the value of serial lactate measurements for prognostic and therapeutic purposes. Information regarding lactate measurement in cats is limited, and further studies are warranted.
To test the extent to which learners performing a simple keyboard passage would be affected by directing their focus of attention to different aspects of their movements, 16 music majors performed a brief keyboard passage under each of four focus conditions arranged in a counterbalanced design-a total of 64 experimental sessions. As they performed the test passage, participants were directed to focus their attention on either their fingers, the piano keys, the piano hammers, or the sound produced. Complete MIDI data for all responses were digitally recorded by software written specifically for this experiment. Consistent with findings obtained in tests of other physical skills, the results show that performance was most accurate and generalizable when participants focused on the effects their movements produced rather than on the movements themselves, and that the more distal the focus of attention, the more accurate the motor control.The skillful execution of complex motor behavior requires efficient processing of sensory feedback, which facilitates moment-to-moment adjustments in the parameters of movements that skilled behaviors comprise. Of course, the nature of skillful movement changes over time, as learners become more familiar with movement structures and more accurate in their performance. In tasks as varied as riding a bicycle, hitting a baseball, and playing the piano, there are numerous sources of sensory feedback,
Background and rationale MicroRNAs (miRs) recently emerged as prominent regulators of cancer processes. In the current study, we aimed at elucidating regulatory pathways and mechanisms through which miR-494, one of the miR species found to be downregulated in CCA, participates in cancer homeostasis. miR-494 was identified as downregulated in CCA based on miR arrays. Its expression was verified with quantitative real time RT-PCR (qRT-PCR). To enforce miR expression, we employed both transfection methods, as well as a retroviral construct to stably overexpress miR-494. Main Results Upregulation of miR-494 in cancer cells decreased growth, consistent with a functional role. mRNA arrays of cells treated with miR-494, followed by pathway analysis, suggested that miR-494 impacts cell cycle regulation. Cell cycle analyses demonstrated that miR-494 induces a significant G1/S checkpoint reinforcement. Further analyses demonstrated that miR-494 downregulates multiple molecules involved in this transition checkpoint. Luciferase reporter assays demonstrated a direct interaction between miR-494 and the 3’-Untranslated Region (UTR) of Cyclin-dependent-kinase 6 (CDK6). Last, xenograft experiments demonstrated that miR-494 induces a significant cancer growth retardation in-vivo. Conclusions Our findings demonstrate that miR-494 is downregulated in CCA and that its upregulation induces cancer cell growth retardation through multiple targets involved in G1-S transition. These findings support the paradigm that miRs are salient cellular signaling pathway modulators, and thus represent attractive therapeutic targets. miR-494 emerges as an important regulator of cholangiocarcinoma growth and its further study may lead to the development of novel therapeutics.
The paternally expressed imprinted Retrotransposon-like 1 (Rtl1/Peg11) is a retrotransposon-derived gene that has evolved a function in eutherian placentation. Seven miRNAs, including miR-127, are processed from a maternally expressed antisense Rtl1 transcript (Rtl1as) and regulate Rtl1 levels through RNAi-mediated post-transcriptional degradation. To determine the relative functional role of Rtl1as miRNAs in Rtl1 dosage, we generated a mouse specifically deleted for miR-127. The miR-127 knockout mice exhibit placentomegaly with specific defects within the labyrinthine zone involved in maternal-fetal nutrient transfer. Although fetal weight is unaltered, specific Rtl1 transcripts and protein levels are increased in both the fetus and placenta. Phenotypic analysis of single (ΔmiR-127/Rtl1 or miR-127/ΔRtl1) and double (ΔmiR-127/ΔRtl1) heterozygous miR-127 and Rtl1 deficient mice indicate that Rtl1 is the main target gene of miR-127 in placental development. Our results demonstrate that miR-127 is an essential regulator of Rtl1 mediated by a trans-homologue interaction between reciprocally imprinted genes on the maternally and paternally inherited chromosomes.
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