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101.
Swoap SJ Rathvon M Gutilla M 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,293(1):R468-R473
Torpor, a state characterized by a well-orchestrated reduction of metabolic rate and body temperature (T(b)), is employed for energetic savings by organisms throughout the animal kingdom. The nucleotide AMP has recently been purported to be a primary regulator of torpor in mice, as circulating AMP is elevated in the fasted state, and administration of AMP causes severe hypothermia. However, we have found that the characteristics and parameters of the hypothermia induced by AMP were dissimilar to those of fasting-induced torpor bouts in mice. Although administration of AMP induced hypothermia (minimum T(b) = 25.2 +/- 0.6 degrees C) similar to the depth of fasting-induced torpor (24.9 +/- 1.5 degrees C), ADP and ATP were equally effective in lowering T(b) (minimum T(b): 24.8 +/- 0.9 degrees C and 24.0 +/- 0.5 degrees C, respectively). The maximum rate of T(b) fall into hypothermia was significantly faster with injection of adenine nucleotides (AMP: -0.24 +/- 0.03; ADP: -0.24 +/- 0.02; ATP: -0.25 +/- 0.03 degrees C/min) than during fasting-induced torpor (-0.13 +/- 0.02 degrees C/min). Heart rate decreased from 755 +/- 15 to 268 +/- 17 beats per minute (bpm) within 1 min of AMP administration, unlike that observed during torpor (from 646 +/- 21 to 294 +/- 19 bpm over 35 min). Finally, the hypothermic effect of AMP was blunted with preadministration of an adenosine receptor blocker, suggesting that AMP action on T(b) is mediated via the adenosine receptor. These data suggest that injection of adenine nucleotides into mice induces a reversible hypothermic state that is unrelated to fasting-induced torpor. 相似文献
102.
Meaghan L. Rourke Wayne Robinson Lee J. Baumgartner Jonathon Doyle Ivor Growns Jason D. Thiem 《Restoration Ecology》2019,27(2):399-407
River regulation infrastructure has been implicated in worldwide aquatic biodiversity loss. In‐stream barriers such as weirs prevent fish migration and the impact can be particularly severe for diadromous species. Fishways are frequently installed on in‐stream barriers to reconnect migratory pathways and rehabilitate diadromous fish populations. Sequential fishways may be necessary in rivers where multiple barriers prevent migration. We monitored a coastal fish community's response to fish passage restoration at 10 predominantly low‐level weirs in the freshwater reaches of the Nepean River in southeastern Australia. Few studies have simultaneously assessed fish community passage at successive fishways within a river system. Prior to the installation of the fishways, there was a gradient of reduced species diversity in an upstream direction including the absence of many diadromous species, despite the regular inundation frequency of most weirs. Following the installation of the fishways, species diversity was still greater in the downstream monitoring sites; however, there was evidence of a positive change in fish community structure in middle and upstream sites. Most notably, three diadromous species rapidly expanded their distribution upstream and one amphidromous species expanded its downstream distribution. This study demonstrates appropriately designed successive fishways can successfully reconnect river systems for an entire fish community, encompassing species with a broad range of swimming abilities and diverse life histories. 相似文献
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The placenta facilitates the exchange of nutrients and wastes in an effort to promote fetal development. Disruptions in the establishment of the placenta and its interactions with the maternal uterus are potential causes of pregnancy failure. In this study we investigated the pregnancy phenotype of two inbred rat strains: the Dahl Salt Sensitive (DSS) strain and the Brown Norway (BN) strain. The DSS strain is reported to have large litters, whereas the BN strain has small litters. Pregnant female rats of each strain were killed on various days of gestation. At the time of killing, the number of viable versus dead and/or resorbing conceptuses was determined. Placental tissues from viable conceptuses were collected and processed for biochemical and histologic analyses. The number of viable conceptuses at Days 8.5 and 18.5 of gestation was significantly greater in DSS versus BN rats. Additionally, the number of resorbing and/or dying conceptuses was significantly greater in the BN strain than in the DSS strain. Maternal responses to pregnancy and elements of placental and fetal development in DSS and BN rats differed. Immunohistologic analysis of placentation and gene expression profiles revealed that trophoblast cell invasion into the uterine mesometrial compartment was significantly less in the BN strain versus the DSS strain. In contrast, the uterine natural killer cell population was reciprocally expanded in the BN strain. The impairment in trophoblast cell invasion in BN rats was associated with a smaller junctional zone compartment of the chorioallantoic placenta. Collectively, the data indicate that BN rats exhibit a unique form of placentation and may represent an excellent model for investigating the genetics of placental development. 相似文献
106.
Joseph G. Jardine Devin Sok Jean-Philippe Julien Bryan Briney Anita Sarkar Chi-Hui Liang Erin M. Scherer Carole J. Henry Dunand Yumiko Adachi Diwanji Devan Jessica Hsueh Meaghan Jones Oleksandr Kalyuzhniy Michael Kubitz Skye Spencer Matthias Pauthner Karen L. Saye-Francisco Fabian Sesterhenn Patrick C. Wilson Denise A. Galloway Robyn L. Stanfield Ian A. Wilson Dennis R. Burton William R. Schief 《PLoS pathogens》2016,12(9)
107.
Hing L. Sham Herman Stein Cheryl A. Rempel Jerome Cohen Jacob J. Plattner 《FEBS letters》1987,220(2):299-301
We have designed and synthesized a series of small peptides containing a perfluoroalkyl ketone group at the C-terminal position of the angiotensin I sequence as inhibitors of human renin. From this series of compounds, 8 and 10 showed strong inhibition of human renin (IC50 = 3 × 10−9, 7 × 10−9 M, respectively). Compound 10 did not inhibit pepsin and cathepsin D at 10−4 M. Comparison of the IC50 of compound 8 and compound 11 (8.7 × 10−7 M) demonstrated the marked effect of the perfluoropropyl group on the potency of inhibition on renin, presumably due to the strong electron-withdrawing effect causing the ketone in 8 to exist predominantly as the hydrate — thus mimicking the tetrahedral transition state during hydrolysis of the scissile Leu10—Val11 amide bond. 相似文献
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109.
Maria A. Nagel April Rempel Jonathon Huntington Forrest Kim Alexander Choe Don Gilden 《Journal of virology》2014,88(14):8189-8192
Alphaherpesvirus reactivation from thoracic sympathetic ganglia (TSG) and transaxonal spread to target organs cause human visceral disease. Yet alphaherpesvirus latency in TSG has not been well characterized. In this study, quantitative PCR detected varicella-zoster virus (VZV), herpes simplex virus 1 (HSV-1), and HSV-2 DNA in 117 fresh TSG obtained postmortem from 15 subjects. VZV DNA was found in 76 (65%) ganglia from all subjects, HSV-1 DNA was found in 5 (4%) ganglia from 3 subjects, and no HSV-2 was found. 相似文献
110.
Robert S. Rempel Charles M. Francis Jeffrey N. Robinson Margaret Campbell 《Journal of Field Ornithology》2013,84(1):86-97
ABSTRACT Acoustic recording systems are being used more frequently to estimate habitat occupancy or relative abundance, and to monitor population trends over time. A potential concern with digital recording systems is that changes in technology could affect detectability of birds and cause bias in trend estimates based on counts of birds detected. We evaluated several currently available commercial recording systems ranging from low‐cost multipurpose digital recorders to custom‐designed wildlife recorders (US$250–$7000 price range) to examine possible differences among systems in species detection. We made recordings during Breeding Bird Surveys (BBS) counts using several units concurrently, and asked several expert birders to listen to the recordings in a factorial design. We found that birders detected, on average, 10% fewer species on some units compared to others, though there was high variance. Analysis of a subset of recordings, using spectrograms and repeated listening, suggested that ~90% of species on each BBS stop could be clearly detected on all units. The remaining species could be identified on at least one unit, but were hard or impossible to detect on others. We found that the recording unit with the lowest empirical signal‐to‐noise‐ratio (SNR) had the lowest number of birds detected on the BBS recordings, and that frequency‐specific SNR differed among units. Missed detections were likely related to variation in internal noise and frequency‐dependent sensitivity of the units, and were an issue for all systems regardless of price. We caution that researchers using recorders need to consider variation among recording systems in their study design, particularly for long‐term monitoring programs. 相似文献