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71.
A Y chromosome-linked factor impairs NK T development 总被引:1,自引:0,他引:1
Wesley JD Tessmer MS Paget C Trottein F Brossay L 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(6):3480-3487
Valpha14 invariant (Valpha14i) NK T cell development is unique from mainstream T cell selection, and the polygenic factors that influence NK T cell ontogeny are still unclear. In this study, we report the absence of Valpha14i NK T cells in B6.IFN-alphabetaR1-/- male mice, whereas both the conventional T and NK cell populations are relatively unaffected. The lack of Valpha14i NK T cells in the B6.IFN-alphabetaR1-/- males is not due to an insufficient level of CD1d1 or a defect in CD1d1-Ag presentation, but it is intrinsic to the male Valpha14i NK T cells. This surprising defect displays >or=99% penetrance in the male population, whereas female mice remain unaffected, indicating the deficiency is not X linked. Analysis of the Valpha14i NK T cell compartment in B6.Tyk2-/-, B6.STAT1-/-, 129.IFN-alphabetaR1-/-, and B6.IFN-alphabetaR1-/+ mice demonstrate that the deficiency is linked to the Y chromosome, but independent of IFN-alphabeta. This is the first study demonstrating that Y-linked genes can exclusively impact Valpha14i NK T development and further highlight the unique ontogeny of these innate T cells. 相似文献
72.
The validity of evolutionary explanations of vocal sexual dimorphism hinges upon whether or not individuals with more sexually dimorphic voices have higher reproductive success than individuals with less dimorphic voices. However, due to modern birth control methods, these data are rarely described, and mating success is often used as a second-rate proxy. Here, we test whether voice pitch predicts reproductive success, number of children born and child mortality in an evolutionarily relevant population of hunter-gatherers. While we find that voice pitch is not related to reproductive outcomes in women, we find that men with low voice pitch have higher reproductive success and more children born to them. However, voice pitch in men does not predict child mortality. These findings suggest that the association between voice pitch and reproductive success in men is mediated by differential access to fecund women. Furthermore, they show that there is currently selection pressure for low-pitch voices in men. 相似文献
73.
Lovering AT Stickland MK Kelso AJ Eldridge MW 《American journal of physiology. Heart and circulatory physiology》2007,292(4):H1777-H1781
Postmortem microsphere studies in adult human lungs have demonstrated the existence of intrapulmonary arteriovenous pathways using nonphysiological conditions. The aim of the current study was to determine whether large diameter (>25 and 50 microm) intrapulmonary arteriovenous pathways are functional in human and baboon lungs under physiological perfusion and ventilation pressures. We used fresh healthy human donor lungs obtained for transplantation and fresh lungs from baboons (Papio c. anubis). Lungs were ventilated with room air by using a peak inflation pressure of 15 cm H(2)O and a positive end-expiratory pressure of 5 cm H(2)O. Lungs were perfused between 10 and 20 cm H(2)O by using a phosphate-buffered saline solution with 5% albumin. We infused a mixture of 25- and 50-microm microspheres (0.5 and 1 million total for baboons and human studies, respectively) into the pulmonary artery and collected the entire pulmonary venous outflow. Under these conditions, evidence of intrapulmonary arteriovenous anastomoses was found in baboon (n = 3/4) and human (n = 4/6) lungs. In those lungs showing evidence of arteriovenous pathways, 50-microm microspheres were always able to traverse the pulmonary circulation, and the fraction of transpulmonary passage ranged from 0.0003 to 0.42%. These data show that intrapulmonary arteriovenous pathways >50 microm in diameter are functional under physiological ventilation and perfusion pressures in the isolated lung. These pathways provide an alternative conduit for pulmonary blood flow that likely bypasses the areas of gas exchange at the capillary-alveolar interface that could compromise both gas exchange and the ability of the lung to filter out microemboli. 相似文献
74.
Matthew L. Faron Blake W. Buchan Josh Hyke Neil Madisen Jennifer L. Lillie Paul A. Granato Deborah A. Wilson Gary W. Procop Susan Novak-Weekley Elizabeth Marlowe Joven Cumpio Christen Griego-Fullbright Sandra Kindig Karen Timm Stephen Young Nathan A. Ledeboer 《PloS one》2015,10(11)
The prompt and accurate identification of bacterial pathogens is fundamental to patient health and outcome. Recent advances in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) have revolutionized bacterial identification in the clinical laboratory, but uniform incorporation of this technology in the U.S. market has been delayed by a lack of FDA-cleared systems. In this study, we conducted a multicenter evaluation of the MALDI Biotyper CA (MBT-CA) System (Bruker Daltonics Inc, Billerica, MA) for the identification of aerobic gram-negative bacteria as part of a 510(k) submission to the FDA. A total of 2,263 aerobic gram negative bacterial isolates were tested representing 23 genera and 61 species. Isolates were collected from various clinical sources and results obtained from the MBT-CA System were compared to DNA sequencing and/or biochemical testing. Isolates that failed to report as a "high confidence species ID" [log(score) ≥2.00] were re-tested using an extraction method. The MBT-CA System identified 96.8% and 3.1% of isolates with either a "high confidence" or a "low confidence" [log(score) value between 1.70 and <2.00] species ID, respectively. Two isolates did not produce acceptable confidence scores after extraction. The MBT-CA System correctly identified 99.8% (2,258/2,263) to genus and 98.2% (2,222/2,263) to species level. These data demonstrate that the MBT-CA System provides accurate results for the identification of aerobic gram-negative bacteria. 相似文献
75.
Hormonally regulated programmed cell death in barley aleurone cells 总被引:13,自引:0,他引:13
Cell death was studied in barley (cv Himalaya) aleurone cells treated with abscisic acid and gibberellin. Aleurone protoplasts incubated in abscisic acid remained viable in culture for at least 3 weeks, but exposure to gibberellin initiated a series of events that resulted in death. Between 4 and 8 days after incubation in gibberellin, >70% of all protoplasts died. Death, which occurred after cells became highly vacuolated, was manifest by an abrupt loss of plasma membrane integrity followed by rapid shrinkage of the cell corpse. Hydrolysis of DNA began before death and occurred as protoplasts ceased production of alpha-amylase. DNA degradation did not result in the accumulation of discrete low molecular weight fragments. DNA degradation and cell death were prevented by LY83583, an inhibitor of gibberellin signaling in barley aleurone. We conclude that cell death in aleurone cells is hormonally regulated and is the final step of a developmental program that promotes successful seedling establishment. 相似文献
76.
Frank Marlowe 《Human nature (Hawthorne, N.Y.)》2000,11(1):27-42
Menopause is puzzling because life-history theory predicts there should be no selection for outliving one’s reproductive capacity.
Adaptive explanations of menopause offered thus far turn on women’s long-term investment in offspring and grandoffspring,
all variations on the grandmother hypothesis. Here, I offer a very different explanation. The patriarch hypothesis proposes
that once males became capable of maintaining high status and reproductive access beyond their peak physical condition, selection
favored the extension of maximum life span in males. Because the relevant genes were not on the Y chromosome, life span increased
in females as well. However, the female reproductive span was constrained by the depletion of viable oocytes, which resulted
in menopause.
Frank Marlowe, Ph.D., is Assistant Professor of Anthropology at Harvard University. He conducts research with the Hadza and
his interests include the behavioral ecology of mating systems, life-history theory, and cooperation. 相似文献
77.
78.
alpha 1-Proteinase inhibitors (alpha 1-PIs) are members of the serpin
superfamily of proteinase inhibitors, and are important in the maintenance
of homeostasis in a wide variety of animal taxa. Previous studies have
shown that in mice (genus Mus), evolution of alpha 1-PIs is characterized
by gene amplification, region-specific concerted evolution, and rapid
accumulation of amino acid substitutions. The latter occurs primarily in
the reactive center, which is the region of the alpha 1-PI molecule that
determines the inhibitor's specificity for target proteinases. The P1
residue within the reactive center, which is methionine in so-called
orthodox alpha 1-PIs and an amino acid other than methionine in unorthodox
alpha 1-PIs, is a primary determinant of inhibitor specificity. In the
present study, we find that the expression of mRNAs encoding unorthodox
alpha 1-PIs is polymorphic within Mus species, i.e., among individuals or
inbred strains. This is in striking contrast to mRNAs that encode orthodox
alpha 1-PIs, whose concentrations are relatively invariant. The
intraspecies variations in mRNA expression represent polymorphisms in the
structure of the alpha 1- PI gene family. The results, taken together with
previously described aspects of alpha 1-PI evolution, indicate that the
dissimilar levels of polymorphism exhibited by orthodox and unorthodox
alpha 1-PIs, which likely have distinct physiological functions, may
reflect different levels of selective constraint. The significance of this
finding to the evolution of gene families is discussed.
相似文献
79.
Duncan N.E. Stibbard-Hawkes Robert D. Attenborough Frank W. Marlowe 《Evolution and human behavior》2018,39(6):639-651
The measurement of hunting ability has been central to several debates about the goals of men's hunting among the Hadza and other hunter-gatherer populations. Hunting ability has previously been measured indirectly, by weighing the amount of food individuals bring back to camp over an extended period, their central place hunting return rate, and by conducting hunting ability interviews. Despite the centrality of the hunting ability concept, some authors (Hill & Kintigh, 2009) have expressed scepticism that such measures accurately capture individual differences in actual hunting ability. In the current study, we introduce a novel measure of hunting reputation which, unlike previous ones, allows fine-grained distinction between hunters of all reputations. To assess the suitability of this measure as a viable proxy for hunting ability, we address two further questions. First, to what extent do interviewees agree about the hunting ability of their present and former campmates? Second, to what extent does this measure of hunting reputation reflect success in four tasks expected to capture important components of hunting ability? We demonstrate that these measures of hunting reputation appear to reflect variation in these skills. We argue, however, that hunting reputation appears too noisy an index of these skills and, we infer, hunting ability in general for hunting to act, as some have suggested (e.g. Hawkes & Bird, 2002), as an honest signal of cryptic qualities related to hunting ability. 相似文献
80.
Melissa L. Bates Emily T. Farrell Alyssa Drezdon Joseph E. Jacobson Scott B. Perlman Marlowe W. Eldridge 《PloS one》2014,9(7)
Intrapulmonary arteriovenous anastomoses (IPAVs) are large diameter connections that allow blood to bypass the lung capillaries and may provide a route for right-to-left embolus transmission. These anastomoses are recruited by exercise and catecholamines and hypoxia. Yet, whether IPAVs are recruited via direct, oxygen sensitive regulatory mechanisms or indirect effects secondary to redistribution pulmonary blood flow is unknown. Here, we hypothesized that the addition of exercise to hypoxic gas breathing, which increases cardiac output, would augment IPAVs recruitment in healthy humans. To test this hypothesis, we measured the transpulmonary passage of 99mTc-macroaggregated albumin particles (99mTc-MAA) in seven healthy volunteers, at rest and with exercise at 85% of volitional max, with normoxic (FIO2 = 0.21) and hypoxic (FIO2 = 0.10) gas breathing. We found increased 99mTc-MAA passage in both exercise conditions and resting hypoxia. However, contrary to our hypothesis, we found the greatest 99mTc-MAA passage with resting hypoxia. As an additional, secondary endpoint, we also noted that the transpulmonary passage of 99mTc-MAA was well-correlated with the alveolar-arterial oxygen difference (A-aDO2) during exercise. While increased cardiac output has been proposed as an important modulator of IPAVs recruitment, we provide evidence that the modulation of blood flow through these pathways is more complex and that increasing cardiac output does not necessarily increase IPAVs recruitment. As we discuss, our data suggest that the resistance downstream of IPAVs is an important determinant of their perfusion. 相似文献