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Disturbance plays an integral part in generating heterogeneity required for ecosystem persistence, but the increased amplitude and duration of disturbances linked to drivers of global change could result in ecosystem shifts or collapse. Biomonitoring over time provides insights into trajectories of ecosystem change. The responses of two instream animal taxa to two contrasting disturbance events, a major flood event and the long-term cumulative effects of land-use changes, were assessed in 1999–2012 by quantifying variation and change in abundance of functional groups based on flow rate sensitivity, water quality and metrics of ecological condition. All metrics recovered to pre-flood conditions within seven months after the flood event. Similarly, cumulative impacts of land use effected significant decreases in some but not all metrics. Indices that did not change, including SASS total score and ASPT, were the result of insufficient consideration of the decrease in the abundance of sensitive taxa specifically, and the abundance of all taxa in general. The decrease in abundance of sensitive taxa could signal imminent collapse in certain metrics. Evidence is also provided for a shift in the structure of fish assemblages linked to the decrease and loss of taxa sensitive to ecosystem degradation caused by the longer-term impacts of land-use change. 相似文献
3.
Central giant cell lesion of the jaws: study of CCND1 gene amplification and p16INK4a protein levels
Renato Luiz Maia Nogueira Mário Henrique Girão Faria Rafael Lima Verde Osterne Roberta Barroso Cavalcante Ronaldo Albuquerque Ribeiro Cassiano Francisco Weege Nonaka Silvia Helena Barem Rabenhorst 《Journal of molecular histology》2013,44(5):527-534
Central giant cell lesions (CGCLs) are uncommon benign jaw lesions with uncertain etiology and a variable clinical behavior. In neoplasms, alterations in molecules involved in the G1/S checkpoint are frequently found. Loss of p16INK4a expression or overexpression of cyclin D1 may stimulate cell proliferation. The purpose of this study was to analyze CCND1 gene amplification and the expression of p16INK4a in CGCLs. Structural analysis of the CCND1 was performed using chromogenic in situ hybridization. Immmunohistochemistry was used to identify p16INK4a protein levels. Statistical analysis correlated the two biomarkers with clinical behavior and between each other. Twenty-four lesions were included, being 11 aggressive and 13 non-aggressive. Moderate/high-level CCND1 amplification was found in 12 lesions. Also, immunoreactivity for p16INK4a was present in 12 cases, mainly in mononuclear cells. There was a significantly higher level of p16INK4a expression in mononuclear cells of non-aggressive lesions and lesions with moderate/high-level CCND1 amplification in mononuclear cells. It could be speculated that some CGCLs may develop as a true benign neoplasm. The higher expression of p16INK4a in non-aggressive lesions and in cases with moderate/high-level CCND1 amplification may show that these molecules have a role in CGCLs. 相似文献
4.
Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis. 相似文献
5.
Second‐derivative synchronous spectrofluorimetric determination of nebivolol hydrochloride and amlodipine besylate in their combined dosage form 下载免费PDF全文
A rapid, simple, accurate and highly sensitive spectrofluorimetric method was developed for the simultaneous analysis of nebivolol hydrochloride (NEB) and amlodipine besylate (AML). The method was based on measuring the synchronous fluorescence intensity of the drugs at Δλ = 40 nm in methanol. Various experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully studied and optimized. The calibration plots were rectilinear over concentration ranges of 0.05–1.5 µg/mL and 0.5–10 µg/mL for NEB and AML with limits of detection (LOD) of 0.010 and 0.051 µg/mL and limits of quantitation (LOQ) of 0.031 and 0.156, respectively. The peak amplitudes (2D) of the second derivative synchronous fluorimetry (SDSF) were estimated at 282 nm for NEB and at 393 nm for AML. Good linearity was obtained over the concentration ranges. The proposed method was successfully applied to the determination of the studied compounds in laboratory‐prepared mixtures, commercial single and laboratory‐prepared tablets. The results were in good agreement with those obtained using the comparison method. The mean percent recoveries were found to be 100.12 ± 0.77 and 99.91 ± 0.77 for NEB and AML, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Yew Kok Lee Shengnan Jin Shiwei Duan Yen Ching Lim Desmond PY Ng Xueqin Michelle Lin George SH Yeo Chunming Ding 《Biological procedures online》2014,16(1):1-9
Background
DNA methylation plays crucial roles in epigenetic gene regulation in normal development and disease pathogenesis. Efficient and accurate quantification of DNA methylation at single base resolution can greatly advance the knowledge of disease mechanisms and be used to identify potential biomarkers. We developed an improved pipeline based on reduced representation bisulfite sequencing (RRBS) for cost-effective genome-wide quantification of DNA methylation at single base resolution. A selection of two restriction enzymes (TaqαI and MspI) enables a more unbiased coverage of genomic regions of different CpG densities. We further developed a highly automated software package to analyze bisulfite sequencing results from the Solexa GAIIx system.Results
With two sequencing lanes, we were able to quantify ~1.8 million individual CpG sites at a minimum sequencing depth of 10. Overall, about 76.7% of CpG islands, 54.9% of CpG island shores and 52.2% of core promoters in the human genome were covered with at least 3 CpG sites per region.Conclusions
With this new pipeline, it is now possible to perform whole-genome DNA methylation analysis at single base resolution for a large number of samples for understanding how DNA methylation and its changes are involved in development, differentiation, and disease pathogenesis. 相似文献8.
Carvalho Barbosa Rde C Menezes DC Freire TF Sales DC Alencar VH Rabenhorst SH 《Molecular biology reports》2012,39(4):4899-4907
Polymorphisms in genes involved in folate metabolism have been shown to be implicated in breast cancer risk but with contradictory
results. In this case–control study, we investigated the association between MTHFR C677T and A1298C, TYMS 5′-UTR, MTR A2756G and cSHMT C1420T and also the folate carrier (RFC1 G80A) and breast cancer risk in a northeastern Brazilian population. The study included 183 women diagnosed with breast cancer
and 183 controls volunteers without any history of cancer. Also a significant number of healthy individuals were included
for allelic frequency in the population studied. Risk of breast cancer was estimated by conditional logistic regression. An
association with risk was found for women carrying the MTR A2756G polymorphic allele (AG, P = 0.0036; AG/GG, P = 0.0040), and a protective effect in carriers of the RFC1 G80A polymorphic allele (GA, P = 0.0015; AA, P = 0.0042). Stratifying the data by age (cutoff point of 50 years old), different distributions were observed for breast cancer
risk. For women ≤50 years, the risk observed in the presence of the polymorphic allele MTR 2756 (AG/GG) in the general analysis was, restricted to this age group (P = 0.0118). Conversely, for women over 50, the risk of breast cancer development was statistically associated with the MTHFR 677CT genotype, but especially significant was risk associated with the presence of the polymorphic allele of cSHMT C1420T (P = 0.0120) and the protective effect associated with the RFC1 G80A polymorphism allele (P = 0.0021), was restrict to this age group. These data indicate that the cutoff age used (50 years old) was appropriate, since
it was able to discriminate risk in each age group in the population studied and also to point to the importance of age in
the analyses of cancer-associated polymorphisms. 相似文献
9.
Ramirez DM Leppla SH Schneerson R Shiloach J 《Journal of industrial microbiology & biotechnology》2002,28(4):232-238
The protective antigen (PA) is one of the three components of the anthrax toxin. It is a secreted nontoxic protein with a
molecular weight of 83 kDa and is the major component of the currently licensed human vaccine for anthrax. Due to limitations
found in the existing vaccine formulation, it has been proposed that genetically modified PA may be more effective as a vaccine.
The expression and the stability of two recombinant PA (rPA) variants, PA-SNKE-ΔFF-E308D and PA-N657A, were studied. These
proteins were expressed in the nonsporogenic avirulent strain BH445. Initial results indicated that PA-SNKE-ΔFF-E308D, which
lacks two proteolysis-sensitive sites, is more stable than PA-N657A. Process development was conducted to establish an efficient
production and purification process for PA-SNKE-ΔFF-E308D. pH, media composition, growth strategy and protease inhibitors
composition were analyzed. The production process chosen was based on batch growth of B. anthracis using tryptone and yeast extract as the only source of carbon, pH control at 7.5, and antifoam 289. Optimal harvest time
was 14–18 h after inoculation, and EDTA (5 mM) was added upon harvest for proteolysis control. Recovery of the rPA was performed
by expanded-bed adsorption (EBA) on a hydrophobic interaction chromatography (HIC) resin, eliminating the need for centrifugation,
microfiltration and diafiltration. The EBA step was followed by ion exchange and gel filtration. rPA yields before and after
purification were 130 and 90 mg/l, respectively. The purified rPA, without further treatment, treated with small amounts of
formalin or adsorbed on alum, induced, high levels of IgG anti-PA with neutralization activities. Journal of Industrial Microbiology & Biotechnology (2002) 28, 232–238 DOI: 10.1038/sj/jim/7000239
Received 28 August 2001/ Accepted in revised form 20 December 2001 相似文献
10.
SH Chew 《Biotechnic & histochemistry》2013,88(5-6):177-183
The phagocytic activity of neuroglial cells in adult feline degenerating optic nerve was investigated by immunocytochemistry at both light and electron microscopy levels. Degeneration was initiated by unilateral eye enucleation and the segment distal to the transection showing true Wallerian degeneration was examined. Following enucleation, twelve adult domestic cats were examined over a period of seven to 215 days. All cases showed slow clearance of myelin debris and absence of proliferating monocytes throughout the post-enucleation period. All phagocytic cells present were neuroglial cells, and many of these cells expressed oligodendroglial antigens. These findings demonstrate the persistence of an active population of oligodendrocytes that might play an additional functional role during Wallerian degeneration of feline optic nerve. 相似文献