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1.
K Rithidech J A Hotchkiss W C Griffith R F Henderson A L Brooks 《Mutation research》1990,241(1):67-73
To determine whether ozone is clastogenic at environmentally relevant exposure levels, rats were exposed for 6 h to 0.0, 0.12, 0.27, or 0.80 ppm ozone. The alveolar macrophages were isolated from animals sacrificed 28 h after the end of the exposure. The mitotic index and frequency of chromosome aberrations were determined. No change in the mitotic index was detected following 0.12 ppm ozone exposure. A significant decrease in mitotic index was observed after exposure to 0.27 ppm ozone; a significant (4-fold) increase in the frequency of dividing macrophages was detected following exposure to 0.8 ppm ozone. Only chromatid-type aberrations were observed. There was a significant increase in the frequency of cells with chromatid gaps and in the frequency of cells with chromatid deletions. Animals exposed to 0.27 ppm ozone had the highest proportion of cells with chromatid deletions (0.172) relative to background level (0.028). No exchanges or chromosome-type aberrations were detected in any of the animals. These data suggest that ozone, at relatively low levels, is clastogenic in macrophages from exposed rats. 相似文献
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Diego A. Miranda Ji-Hyun Kim Long N. Nguyen Wang Cheng Bryan C. Tan Vera J. Goh Jolene S. Y. Tan Jadegoud Yaligar Bhanu Prakash KN S. Sendhil Velan Hongyan Wang David L. Silver 《The Journal of biological chemistry》2014,289(14):9560-9572
Triglycerides within the cytosol of cells are stored in a phylogenetically conserved organelle called the lipid droplet (LD). LDs can be formed at the endoplasmic reticulum, but mechanisms that regulate the formation of LDs are incompletely understood. Adipose tissue has a high capacity to form lipid droplets and store triglycerides. Fat storage-inducing transmembrane protein 2 (FITM2/FIT2) is highly expressed in adipocytes, and data indicate that FIT2 has an important role in the formation of LDs in cells, but whether FIT2 has a physiological role in triglyceride storage in adipose tissue remains unproven. Here we show that adipose-specific deficiency of FIT2 (AF2KO) in mice results in progressive lipodystrophy of white adipose depots and metabolic dysfunction. In contrast, interscapular brown adipose tissue of AF2KO mice accumulated few but large LDs without changes in cellular triglyceride levels. High fat feeding of AF2KO mice or AF2KO mice on the genetically obese ob/ob background accelerated the onset of lipodystrophy. At the cellular level, primary adipocyte precursors of white and brown adipose tissue differentiated in vitro produced fewer but larger LDs without changes in total cellular triglyceride or triglyceride biosynthesis. These data support the conclusion that FIT2 plays an essential, physiological role in fat storage in vivo. 相似文献
4.
Kanokporn Noy Rithidech Paiboon Reungpatthanaphong Louise Honikel Adam Rusek Sanford R. Simon 《Radiation and environmental biophysics》2010,49(3):405-419
The objective of this study was to determine the kinetics of nuclear factor-kappa B (NF-κB) activation and cytokine expression
in bone marrow (BM) cells of exposed mice as a function of the dose rate of protons. The cytokines included in this study
are pro-inflammatory [i.e., tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and IL-6] and anti-inflammatory
cytokines (i.e., IL-4 and IL-10). We gave male BALB/cJ mice a whole-body exposure to 0 (sham-controls) or 1.0 Gy of 100 MeV
protons, delivered at 5 or 10 mGy min−1, the dose and dose rates found during solar particle events in space. As a reference radiation, groups of mice were exposed
to 0 (sham-controls) or 1 Gy of 137Cs γ rays (10 mGy min−1). After irradiation, BM cells were collected at 1.5, 3, 24 h, and 1 month for analyses (five mice per treatment group per
harvest time). The results indicated that the in vivo time course of effects induced by a single dose of 1 Gy of 100 MeV protons
or 137Cs γ rays, delivered at 10 mGy min−1, was similar. Although statistically significant levels of NF-κB activation and pro-inflammatory cytokines in BM cells of
exposed mice when compared to those in the corresponding sham controls (Student’s t-test, p < 0.05 or <0.01) were induced by either dose rate, these levels varied over time for each protein. Further, only a dose rate
of 5 mGy min−1 induced significant levels of anti-inflammatory cytokines. The results indicate dose-rate effects of protons. 相似文献
5.
Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis 总被引:4,自引:1,他引:3
Leung AY Leung JC Chan LY Ma ES Kwan TT Lai KN Meng A Liang R 《Histochemistry and cell biology》2005,124(2):105-111
We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic
component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP)
was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression
of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded
by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic
progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic
compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial
stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed
in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly
upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues
and to identify a population of progenitor cells whose significance would have to be further investigated. 相似文献
6.
Montree Tungjai Elbert B. Whorton Kanokporn Noy Rithidech 《Radiation and environmental biophysics》2013,52(3):339-350
It has been well established that the bone marrow (BM) is a radiosensitive tissue, but the radiosensitivity of the heart is poorly understood. In this study, we investigated the comparative effects of 28Silicon (28Si) ions (one type of heavy ion found in space) on tissue from the heart and the BM of exposed mice. We gave adult male CBA/CaJ mice a whole-body exposure to a total dose of 0, 0.1, 0.25, or 0.5 Gy of 300 MeV/nucleon (n) 28Si ions, using a fractionated schedule (two exposures, 15 days apart that totaled each selected dose). The heart and BM were collected from 5 mice per treatment group at various times up to 6 months post-irradiation. In each mouse, we obtained tissue lysates from the heart and from the total population of BM cells for measuring the levels of cleaved poly (ADP-ribose) polymerase (cleaved PARP, a marker of apoptotic cell death) and the levels of activated nuclear factor-kappa B (NF-κB) and selected NF-κB-regulated cytokines known to be involved in inflammatory responses. Our data showed that, up to 6 months post-irradiation, the levels of apoptotic cell death and inflammatory responses in tissues from the heart and BM collected from exposed mice were statistically higher than those in sham controls. Hence, these findings are suggestive of chronic apoptotic cell death and inflammation in both tissues after exposure to 28Si ions. In summary, our data are indicative of a possible association between exposure to 28Si ions during space flight and long-term health risk. 相似文献
7.
In this article, we report the synthesis of Na2Sr1‐x(PO4)F:Eux phosphor via a combustion method. The influence of different annealing temperatures on the photoluminescence properties was investigated. The phosphor was excited at both 254 and 393 nm. Na2Sr1‐x(PO4)F:Eux3+ phosphors emit strong orange and red color at 593 and 612 nm, respectively, under both excitation wavelengths. Na2Sr1‐x(PO4)F:Eux3+ phosphors annealed at 1050°C showed stronger emission intensity compared with 600, 900 and 1200°C. Moreover, Na2Sr1‐x(PO4)F:Eux3+ phosphor was found to be more intense when compared with commercial Y2O3:Eu3+ phosphor. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
Valeria Valente Silvia A Teixeira Luciano Neder Oswaldo K Okamoto Sueli M Oba-Shinjo Suely KN Marie Carlos A Scrideli Maria L Pa?ó-Larson Carlos G Carlotti 《BMC molecular biology》2009,10(1):17
Background
Considering the broad variation in the expression of housekeeping genes among tissues and experimental situations, studies using quantitative RT-PCR require strict definition of adequate endogenous controls. For glioblastoma, the most common type of tumor in the central nervous system, there was no previous report regarding this issue. 相似文献9.
Genomic analysis of the relationship between gene expression variation and DNA polymorphism in Drosophila simulans 下载免费PDF全文
Background
Understanding how DNA sequence polymorphism relates to variation in gene expression is essential to connecting genotypic differences with phenotypic differences among individuals. Addressing this question requires linking population genomic data with gene expression variation.Results
Using whole genome expression data and recent light shotgun genome sequencing of six Drosophila simulans genotypes, we assessed the relationship between expression variation in males and females and nucleotide polymorphism across thousands of loci. By examining sequence polymorphism in gene features, such as untranslated regions and introns, we find that genes showing greater variation in gene expression between genotypes also have higher levels of sequence polymorphism in many gene features. Accordingly, X-linked genes, which have lower sequence polymorphism levels than autosomal genes, also show less expression variation than autosomal genes. We also find that sex-specifically expressed genes show higher local levels of polymorphism and divergence than both sex-biased and unbiased genes, and that they appear to have simpler regulatory regions.Conclusion
The gene-feature-based analyses and the X-to-autosome comparisons suggest that sequence polymorphism in cis-acting elements is an important determinant of expression variation. However, this relationship varies among the different categories of sex-biased expression, and trans factors might contribute more to male-specific gene expression than cis effects. Our analysis of sex-specific gene expression also shows that female-specific genes have been overlooked in analyses that only point to male-biased genes as having unusual patterns of evolution and that studies of sexually dimorphic traits need to recognize that the relationship between genetic and expression variation at these traits is different from the genome as a whole. 相似文献10.
To date, there is scant information on in vivo induction of chromosomal damage by heavy ions found in space (i.e. 56Fe ions). For radiation-induced response to be useful for risk assessment, it must be established in in vivo systems especially
in cells that are known to be at risk for health problems associated with radiation exposure (such as hematopoietic cells,
the known target tissue for radiation-induced leukemia). In this study, the whole genome multicolor fluorescence in situ hybridization
(mFISH) technique was used to examine the in vivo induction of chromosomal damage in hematopoietic tissues, i.e. bone marrow
cells. These cells were collected from CBA/CaJ mice at day 7 following whole-body exposure to different doses of 1 GeV/amu
56Fe ions (0, 0.1, 0.5 and 1.0 Gy) or 137Cs γ rays as the reference radiation (0, 0.5, 1.0 and 3.0 Gy, at the dose rate of 0.72 Gy/min using a GammaCell40). These
radiation doses were the average total-body doses. For each radiation type, there were four mice per dose. Several types of
aberrations in bone marrow cells collected from mice exposed to either type of radiation were found. These were exchanges
and breaks (both chromatid- and chromosome-types). Chromosomal exchanges included translocations (Robertsonian or centric
fusion, reciprocal and incomplete types), and dicentrics. No evidence of a non-random involvement of specific chromosomes
in any type of aberrations observed in mice exposed to 56Fe ions or 137Cs γ rays was found. At the radiation dose range used in our in vivo study, the majority of exchanges were simple. Complex
exchanges were detected in bone marrow cells collected from mice exposed to 1 Gy of 56Fe ions or 3 Gy of 137Cs γ rays only, but their frequencies were low. Overall, our in vivo data indicate that the frequency of complex chromosome
exchanges was not significantly different between bone marrow cells collected from mice exposed to 56Fe ions or 137Cs γ rays. Each type of radiation induced significant dose-dependent increases (ANOVA, P < 0.01) in the frequencies of chromosomal damage, including the numbers of abnormal cells. Based upon the linear-terms of
dose-response curves, 56Fe ions were 1.6 (all types of exchanges), 4.3 (abnormal cells) and 4.2 (breaks, both chromatid- and chromosome-types) times
more effective than 137Cs γ rays in inducing chromosomal damage. 相似文献