The Earliest Evidence of Holometabolan Insect Pupation in Conifer Wood

Background: The pre-Jurassic record of terrestrial wood borings is poorly resolved, despite body fossil evidence of insect diversification among xylophilic clades starting in the late Paleozoic. Detailed analysis of borings in petrified wood provides direct evidence of wood utilization by invertebrate animals, which typically comprises feeding behaviors.\ud \ud Methodology/Principal Findings: We describe a U-shaped boring in petrified wood from the Late Triassic Chinle Formation of southern Utah that demonstrates a strong linkage between insect ontogeny and conifer wood resources. Xylokrypta durossi new ichnogenus and ichnospecies is a large excavation in wood that is backfilled with partially digested xylem, creating a secluded chamber. The tracemaker exited the chamber by way of a small vertical shaft. This sequence of behaviors is most consistent with the entrance of a larva followed by pupal quiescence and adult emergence — hallmarks of holometabolous insect ontogeny. Among the known body fossil record of Triassic insects, cupedid beetles (Coleoptera: Archostemata) are deemed the most plausible tracemakers of Xylokrypta, based on their body size and modern xylobiotic lifestyle.\ud \ud Conclusions/Significance: This oldest record of pupation in fossil wood provides an alternative interpretation to borings once regarded as evidence for Triassic bees. Instead Xylokrypta suggests that early archostematan beetles were leaders in exploiting wood substrates well before modern clades of xylophages arose in the late Mesozoic

Impact of in utero exposure to EtOH on corpus callosum development and paw preference in rats: protective effects of silymarin

BACKGROUND: Using a rat model we have found that the bioflavonoid silymarin (SY) ameliorates some of the negative consequences of in utero exposure to ethanol (EtOH). In the current study our aim was to determine if laterality preference and corpus callosum development were altered in rat offspring whose mothers were provided with a concomitant administration of SY with EtOH throughout gestation. METHODS: We provided pregnant Fisher/344 rats with liquid diets containing 35% ethanol derived calories (EDC) throughout the gestational period. A silymarin/phospholipid compound containing 29.8% silybin was co administered with EtOH to a separate experimental group. We tested the offspring for laterality preference at age 12 weeks. After testing the rats were sacrificed and their brains perfused for later corpus callosum extraction. RESULTS: We observed incomplete development of the splenium in the EtOH-only offspring. Callosal development was complete in all other treatment groups. Rats from the EtOH-only group displayed a left paw preference; whereas control rats were evenly divided between right and left paw preference. Inexplicably both SY groups were largely right paw preferring. CONCLUSIONS: The addition of SY to the EtOH liquid diet did confer some ameliorative effects upon the developing fetal rat brain

NMDA receptors and BAX are essential for Aβ impairment of LTP

Accumulation of amyloid-β (Aβ) is a hallmark of Alzheimer’s disease, a neurodegenerative disorder in which synapse loss and dysfunction are early features. Acute exposure of hippocampal slices to Aβ leads to changes in synaptic plasticity, specifically reduced long-term potentiation (LTP) and enhanced long-term depression (LTD), with no change in basal synaptic transmission. We also report here that D-AP5, a non-selective NMDA receptor antagonist, completely prevented Aβ-mediated inhibition of LTP in area CA1 of the hippocampus. Ro25-6981, an antagonist selective for GluN2B (NR2B) NMDA receptors, only partially prevented this Aβ action, suggesting that GluN2A and GluN2B receptors may both contribute to Aβ suppression of LTP. The effect of Aβ on LTP was also examined in hippocampal slices from BAX −/− mice and wild-type littermates. Aβ failed to block LTP in hippocampal slices from BAX −/− mice, indicating that BAX is essential for Aβ inhibition of LTP

Facilitation of Male Sexual Behavior in Syrian Hamsters by the Combined Action of Dihydrotestosterone and Testosterone

Testosterone (T) controls male Syrian hamster sexual behavior, however, neither of T's primary metabolites, dihydrotestosterone (DHT) and estradiol (E(2)), even in highly supraphysiological doses, fully restores sexual behavior in castrated hamsters. DHT and T apparently interact with androgen receptors differentially to control male sexual behavior (MSB), but whether these two hormones act synergistically or antagonistically to control MSB has received scant experimental attention and is addressed in the present study.Sexually experienced male Syrian hamsters were gonadectomized and monitored 5 weeks later to confirm elimination of the ejaculatory reflex (week 0), at which time they received subcutaneous DHT-filled or empty capsules that remained in situ for the duration of the experiment. Daily injections of a physiological dose of 25 µg T or vehicle commenced two weeks after capsule implantation. MSB was tested 2, 4 and 5 weeks after T treatment began. DHT capsules were no more effective than control treatment for long-term restoration of ejaculation. Combined DHT + T treatment, however, restored the ejaculatory reflex more effectively than T alone, as evidenced by more rapid recovery of ejaculatory behavior, shorter ejaculation latencies, and a greater number of ejaculations in 30 minute tests.DHT and T administered together restored sexual behavior to pre-castration levels more rapidly than did T alone, whereas DHT and vehicle were largely ineffective. The additive actions of DHT and T on MSB are discussed in relation to different effects of these androgens on androgen receptors in the male hamster brain mating circuit

Large-scale analyses of common and rare variants identify 12 new loci associated with atrial fibrillation

Atrial fibrillation affects more than 33 million people worldwide and increases the risk of stroke, heart failure, and death. Fourteen genetic loci have been associated with atrial fibrillation in European and Asian ancestry groups. To further define the genetic basis of atrial fibrillation, we performed large-scale, trans-ancestry meta-analyses of common and rare variant association studies. The genome-wide association studies (GWAS) included 17,931 individuals with atrial fibrillation and 115,142 referents; the exome-wide association studies (ExWAS) and rare variant association studies (RVAS) involved 22,346 cases and 132,086 referents. We identified 12 new genetic loci that exceeded genome-wide significance, implicating genes involved in cardiac electrical and structural remodeling. Our results nearly double the number of known genetic loci for atrial fibrillation, provide insights into the molecular basis of atrial fibrillation, and may facilitate the identification of new potential targets for drug discovery