6,803 research outputs found
Influence of lipopolysaccharide on proinflammatory gene expression in human corneal, conjunctival and meibomian gland epithelial cells
PURPOSE:
Lipopolysaccharide (LPS), a bacterial endotoxin, is known to stimulate leuokotriene B4 (LTB4) secretion by human corneal (HCECs), conjunctival (HConjECs) and meibomian gland (HMGECs) epithelial cells. We hypothesize that this LTB4 effect represents an overall induction of proinflammatory gene expression in these cells. Our objective was to test this hypothesis.
METHODS:
Immortalized HCECs, HConjECs and HMGECs were cultured in the presence or absence of LPS (15 μg/ml) and ligand binding protein (LBP; 150 ng/ml). Cells were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and GeneSifter software.
RESULTS:
Our findings show that LPS induces a striking increase in proinflammatory gene expression in HCECs and HConjECs. These cellular reactions are associated with a significant up-regulation of genes associated with inflammatory and immune responses (e.g. IL-1β, IL-8, and tumor necrosis factor), including those related to chemokine and Toll-like receptor signaling pathways, cytokine-cytokine receptor interactions, and chemotaxis. In contrast, with the exception of Toll-like signaling and associated innate immunity pathways, almost no proinflammatory ontologies were upregulated by LPS in HMGECs.
CONCLUSIONS:
Our results support our hypothesis that LPS stimulates proinflammatory gene expression in HCECs and HConjECs. However, our findings also show that LPS does not elicit such proinflammatory responses in HMGECs
A Cellular Basis for Wolbachia Recruitment to the Host Germline
Wolbachia are among the most widespread intracellular bacteria, carried by thousands of metazoan species. The success of Wolbachia is due to efficient vertical transmission by the host maternal germline. Some Wolbachia strains concentrate at the posterior of host oocytes, which promotes Wolbachia incorporation into posterior germ cells during embryogenesis. The molecular basis for this localization strategy is unknown. Here we report that the wMel Wolbachia strain relies upon a two-step mechanism for its posterior localization in oogenesis. The microtubule motor protein kinesin-1 transports wMel toward the oocyte posterior, then pole plasm mediates wMel anchorage to the posterior cortex. Trans-infection tests demonstrate that factors intrinsic to Wolbachia are responsible for directing posterior Wolbachia localization in oogenesis. These findings indicate that Wolbachia can direct the cellular machintery of host oocytes to promote germline-based bacterial transmission. This study also suggests parallels between Wolbachia localization mechanisms and those used by other intracellular pathogens
Intergenerational Transmission of Reproductive Behavior during the Demographic Transition
New evidence from the Utah Population Database (updp) reveals that at the onset of the fertility transition, reproductive behavior was transmitted across generations—between women and their mothers, as well as between women and their husbands\u27 family of origin. Age at marriage, age at last birth, and the number of children ever born are positively correlated in the data, most strongly among first-born daughters and among cohorts born later in the fertility transition. Intergenerational ties, including the presence of mothers and mothers-in-law, influenced the hazard of progressing to a next birth. The findings suggest that the practice of parity-dependent marital fertility control and inter-birth spacing behavior derived, in part, from the previous generation and that the potential for mothers and mothers-in-law to help in the rearing of children encouraged higher marital fertility
Sperm mobility: mechanisms of fertilizing efficiency, genetic variation and phenotypic relationship with male status in the domestic fowl, Gallus gallus domesticus
When females are sexually promiscuous, sexual selection continues after insemination through sperm
competition and cryptic female choice, and male traits conveying an advantage in competitive fertilization
are selected for. Although individual male and ejaculate traits are known to influence paternity in a competitive
scenario, multiple mechanisms co-occur and interact to determine paternity. The way in which
different traits interact with each other and the mechanisms through which their heritability is maintained
despite selection remain unresolved. In the promiscuous fowl, paternity is determined by the number of
sperm inseminated into a female, which is mediated by male social dominance, and by the quality of the
sperm inseminated, measured as sperm mobility. Here we show that: (i) the number of sperm inseminated
determines how many sperm reach the female sperm-storage sites, and that sperm mobility mediates the
fertilizing efficiency of inseminated sperm, mainly by determining the rate at which sperm are released
from the female storage sites, (ii) like social status, sperm mobility is heritable, and (iii) subdominant
males are significantly more likely to have higher sperm mobility than dominant males. This study indicates
that although the functions of social status and sperm mobility are highly interdependent, the lack of
phenotypic integration of these traits may maintain the variability of male fitness and heritability of fertilizing
efficiency
Testosterone Influence on Gene Expression in Lacrimal Glands of Mouse Models of Sjögren Syndrome
Purpose:
Sjögren syndrome is an autoimmune disorder that occurs almost exclusively in women and is associated with extensive inflammation in lacrimal tissue, an immune-mediated destruction and/or dysfunction of glandular epithelial cells, and a significant decrease in aqueous tear secretion. We discovered that androgens suppress the inflammation in, and enhance the function of, lacrimal glands in female mouse models (e.g., MRL/MpJ-Tnfrsf6lpr [MRL/lpr]) of Sjögren syndrome. In contrast, others have reported that androgens induce an anomalous immunopathology in lacrimal glands of nonobese diabetic/LtJ (NOD) mice. We tested our hypothesis that these hormone actions reflect unique, strain- and tissue-specific effects, which involve significant changes in the expression of immune-related glandular genes.
Methods:
Lacrimal glands were obtained from age-matched, adult, female MRL/lpr and NOD mice after treatment with vehicle or testosterone for up to 3 weeks. Tissues were processed for analysis of differentially expressed mRNAs using CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with bioinformatics and statistical software.
Results:
Testosterone significantly influenced the expression of numerous immune-related genes, ontologies, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in lacrimal glands of MRL/lpr and NOD mice. The nature of this hormone-induced immune response was dependent upon the autoimmune strain, and was not duplicated within lacrimal tissues of nonautoimmune BALB/c mice. The majority of immune-response genes regulated by testosterone were of the inflammatory type.
Conclusions:
Our findings support our hypothesis and indicate a major role for the lacrimal gland microenvironment in mediating androgen effects on immune gene expression
An experimental and theoretical study of transient negative ions in Mg, Zn, Cd and Hg
A range of experimental and theoretical techniques have been applied to the study of transient negative ions (resonances) formed in electron scattering from the Group II metals Mg, Zn, Cd, and Hg at incident electron energies below the first ionization potential. A wealth of resonance structures have been observed and from the experimental observations and theoretical information, classifications are proposed for some of these negative ion states
Evaluation of Magnetic Materials for Very High Frequency Power Applications
This paper investigates the loss characteristics of RF magnetic materials for power conversion applications in the 10 to 100 MHz range. A measurement method is proposed that provides a direct measurement of an inductor quality factor QL as a function of inductor current at RF frequencies, and enables indirect calculation of core loss as a function of flux density. Possible sources of error in measurement and calculation are evaluated and addressed. The proposed method is used to identify loss characteristics of several commercial RF magnetic-core materials. The loss characteristics of these materials, which have not previously been available, are illustrated and compared in tables and figures. The use of the method and data is demonstrated in the design of a magnetic-core inductor, which is applied in a 30-MHz inverter. The results of this paper are thus useful for the design of magnetic components for very high frequency applications.Sheila and Emanuel Landsman FoundationInterconnect Focus Center (United States. Defense Advanced Research Projects Agency and Semiconductor Research Corporation
Periodic variations in the O-C diagrams of five pulsation frequencies of the DB white dwarf EC 20058-5234
Variations in the pulsation arrival time of five independent pulsation frequencies of the DB white dwarf
EC 20058−5234 individually imitate the effects of reflex motion induced by a planet or companion but are
inconsistent when considered in unison. The pulsation frequencies vary periodically in a 12.9 year cycle and
undergo secular changes that are inconsistent with simple neutrino plus photon-cooling models. The magnitude of
the periodic and secular variations increases with the period of the pulsations, possibly hinting that the corresponding
physical mechanism is located near the surface of the star. The phase of the periodic variations appears coupled
to the sign of the secular variations. The standards for pulsation-timing-based detection of planetary companions
around pulsating white dwarfs, and possibly other variables such as subdwarf B stars, should be re-evaluated.
The physical mechanism responsible for this surprising result may involve a redistribution of angular momentum
or a magnetic cycle. Additionally, variations in a supposed combination frequency are shown to match the sum
of the variations of the parent frequencies to remarkable precision, an expected but unprecedented confirmation
of theoretical predictions.Web of Scienc
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