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1.
Vitamin D receptor (VDR) is implicated in the regulation of bone mineral density (BMD). In this study, we performed a meta-analysis to evaluate
the association between the VDR
BsmI (rs1544410) and ApaI (rs7975232) polymorphisms and BMD in Chinese women. Literature was retrieved from PubMed and other databases. The studies
on the association between VDR
BsmI and ApaI genotypes and BMD at the lumbar spine, the femoral neck, the trochanter or the Ward’s triangle in Han Chinese women were
included in this meta-analysis. Pooled BMD differences and 95% confidence intervals (CIs) were calculated using random- or
fixed- effects model. Twenty-five eligible studies, which included 4,075 Chinese women, were identified. No significant difference
was observed for either genotype when the meta-analysis was limited to premenopausal women. In postmenopausal women, BMD differences
were significant for BB vs. Bb [−0.029 (95% CI −0.056, −0.002) g/m2, P = 0.037] at the femoral neck, AA vs. Aa [−0.029 (95% CI −0.051, −0.006) g/m2, P = 0.012] at the lumbar spine, and Aa vs. aa [0.022(95% CI 0.011, 0.033) g/m2, P = 0.000] at the trochanter. These results suggest a modest but statistically significant association between VDR BsmI and ApaI polymorphisms and BMD in Chinese postmenopausal women, with higher BMD in heterozygous subjects. More epidemiological and
mechanistic studies are needed to further investigate the role of VDR gene polymorphisms in regulating BMD and osteoporosis in the future. 相似文献
2.
Hemorrhagic disease (HD) is an important vector-borne disease of white-tailed deer (Odocoileus virginianus). The objective of this study was to determine whether temperature and precipitation were associated with a measure of annual
incidence of HD in white-tailed deer from Virginia. The annual percentages of deer with hoof wall growth interruptions (a
clinical sign of HD) from four climate divisions in the HD endemic area of Virginia recorded during 1993–2006 were used as
indicators of annual HD incidence. Pearson’s correlation coefficients between these indicators of incidence and average temperature
(°F) or total precipitation (in.) for each month, as well as for winter (January–February), early summer (June–July), and
late summer/fall (August–September–October) seasons were calculated. Strong direct correlations between the measure of annual
HD incidence and average temperature for winter (r = 0.39, P = 0.003, n = 57), early summer (r = 0.51, P < 0.0001, n = 57), and late summer/fall (r = 0.42, P = 0.001, n = 57) were evident. There also was a strong inverse correlation between the measured annual HD incidence and June precipitation
(r = −0.44, P = 0.0006, n = 57). Poisson regression models of seasonal temperatures and June precipitation to annual percentage of deer with hoof wall
growth interruptions were developed. Based on Akaike’s Information Criterion with small sample size correction (AICc), the
global model was selected as the top model. Higher winter and summer temperatures may increase vector capacity and competence,
and lower precipitation in June may create favorable breeding sites for midges. 相似文献
3.
Seifi S Tabandeh MR Nazifi S Saeb M Shirian S Sarkoohi P 《Journal of physiology and biochemistry》2012,68(2):193-203
Available experimental data suggest that adiponectin and thyroid hormones have biological interaction in vivo. However, the
effects of thyroid hormones on adipose adiponectin gene expression in thyroid dysfunction are unclear. We induced hyper- (HYPER)
and hypothyroidism (HYPO) by daily administration of a 12 mg/l of levothyroxine and 250 mg/l of methimazole in drinking water
of rats, respectively, for 42 days. The white adipose tissues and serum sample were taken on days 15, 28, 42 and also 2 weeks
after treatment cessation. Analysis of adiponectin gene expression was performed by real-time PCR and 2−ΔΔct method. The levels of adipose tissue adiponectin mRNA in the HYPO rats were decreased during the 6-week treatment when compared
to control rats (<0.05) and were increased significantly 2 weeks after HYPO cessation (P < 0.05). This decline in adiponectin gene expression occurred in parallel with a decrease in T3, T4, fT3 and fT4 concentrations
(P < 0.05). In opposite to HYPO rats, adipose adiponectin gene expression was increased in HYPER rats during the 6-week treatment
in parallel with an increase the thyroid hormones concentrations (P < 0.05), and its expression was decreased 2 weeks after HYPER cessation (P < 0.05). Adiponectin gene expression levels showed significant negative correlations with concentrations of LDL (HYPO; r = −0.806, P = 0.001 and HYPER; r = −0.749, P = 0.002), triglyceride (HYPO; r = −0.825, P = 0.001 and HYPER; r = −0.824, P = 0.001) and significant positive correlations with concentrations of glucose (HYPO; r = 0.674, P = 0.004 and HYPER; r = 0.866, P = 0.001) and HDL (HYPO; r = 0.755, P = 0.001 and HYPER; r = 0.839, P = 0.001). The current study provides evidence that adiponectin gene expression in adipose tissue is regulated by thyroid
hormones at the translation level and that lipid and carbohydrate disturbances in a patient with thyroid dysfunction may be,
in part, due to adiponectin gene expression changes. 相似文献
4.
Tubek S 《Biological trace element research》2006,114(1-3):55-63
The relationship between selected zinc (Zn) metabolism parameters, arterial blood pressure, age, and renin-angiotensin-aldosterone
system in subjects of both sexes with mild primary arterial hypertension is presented in this study. The following parameters
were measured: systolic and diastolic arterial blood pressure, total and ouabain-dependent efflux rate constants of Zn from
lymphocytes, serum and lymphocyte Zn concentrations, serum aldosterone, angiotensin-converting enzyme, sodium and potassium
concentrations, body mass index, and plasma rennin activity. When all subjects are taken into account, no significant age-related
differences were found for serum Zn. If divided into men and women, negative (r=−0.39) and positive (r=0.34) correlations are observed, respectively. Lymphocyte Zn correlated negatively with age in the entire group (r=−0.55) and also for men (r=−0.54) and women (r=−0.57).
The renin-agiotensin-aldosterone system parameters correlated with those of Zn metabolism only for women: plasma rennin activity
with total Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.71); the angiotensin-converting enzyme with total Zn efflux from lymphocytes (r=−0.35), with the oubain-dependent Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.57); serum aldosterone with oubain-dependent Zn efflux from lymphocytes (r=−0.44) and with lymphocyte Zn (r=0.59). For the men, the only positive correlation was that of serum Zn and aldosterone (r=0.45). In all cases (men and women), there was no negative correlation between serum Zn and angiotensin-converting enzyme.
In women, the diastolic blood pressure correlated negatively with total Zn efflux from lymphocytes (r=−0.39), oubain-dependent Zn efflux from lymphocytes (r=−0.49), and serum Zn (r=−0.46); systolic blood pressure correlated negatively with lymphocyte zinc (r=−0.38). In men, the systolic blood pressure had a negative correlation with lymphocyte zinc (r=−0.32), which was also true for the entire group (r=−0.34). These results clearly show gender-related differences in Zn metabolism and indicate the need for further research
to elucidate the possible causes of this phenomenon not only for Zn but for other elements as well. 相似文献
5.
J. L. Falter M. J. Atkinson D. W. Schar R. J. Lowe S. G. Monismith 《Coral reefs (Online)》2011,30(1):53-58
Rates of net community carbon production (mmol C m−2 h−1) were measured continuously in an algal-dominated reef flat community on the Kaneohe Bay barrier reef, Hawaii, for 12 days
at the end of October 2006. The weather became increasingly cloudy during the last 5 days of measurements, resulting in a
sevenfold decline in daily incident light (28–4 Ein m−2 d−1). In response, gross primary production (P) for the reef flat community also decreased sevenfold, varying linearly with light (r
2 = 0.92, n = 12). Community respiration (R) decreased fivefold over this same period and was highly correlated with changes in P (r
2 = 0.84, n = 12). We reason that this short-term coherence between P and R indicates that most of the carbon fixed during this period was rapidly metabolized via plant respiration. We further conclude
that the dominance of autotrophic respiration under general conditions of nutrient-limited growth can explain much of the
balance between P and R that is commonly observed in shallow reef communities. 相似文献
6.
Deniz Özkan Deniz Yüzbaşıoğlu Fatma Ünal Serkan Yılmaz Hüseyin Aksoy 《Cytotechnology》2009,59(2):73-80
The organophosphorous insecticide acephate was tested for its ability to induce in vitro cytogenetic effect in human peripheral
lymphocytes by using the chromosomal aberrations (CAs), sister chromatid exchange (SCE) and micronuclei (MN) assay. The level
of nuclear DNA damage of acephate was evaluated by using the comet assay. Concentrations of 12.5, 25, 50, 100 and 200 μg mL−1 of acephate were used. All concentrations of acephate induced significant increase in the frequency of CAs and in the formation
of MN dose dependently (r = 0.92 at 24 h, r = 0.95 at 48 h for CAs, r = 0.87 for MN). A significant increase was observed in induction of SCE at 50, 100 and 200 μg mL−1 concentrations during 24 h treatment and at all concentrations (except 12.5 μg mL−1) during 48 h treatment period in a dose-dependent manner (r = 0.84 at 24 h, r = 0.88 at 48 h). Acephate did not affect the replicative index and cytokinesis-block proliferation index (CBPI). However,
it significantly decreased the mitotic index at all three highest concentrations (50, 100, 200 μg mL−1) for 24 h treatment and at all concentrations (except 12.5 μg mL−1) for 48 h treatment, dose-dependently (r = 0.94 at 24 h, r = 0.92 at 48 h). A significant increase in mean comet tail length was observed at 100 and 200 μg mL−1 concentrations compared with negative control in a concentration-dependent manner (r = 0.94). The mean comet tail intensity was significantly increased at only 200 μg mL−1 concentration. The present results indicate that acephate is a clastogenic, cytotoxic agent and it causes DNA damage at high
concentrations in human lymphocytes in culture. 相似文献
7.
Cyanobacteria are commonly used for the phytostimulation and biofertilization of agriculture crops due to their nitrogen-fixing
ability. However, the contribution by their phytohormones has been neglected. This study focuses on the screening of rhizospheric
and free-living cyanobacteria for in vitro phytohormones production and growth stimulation in wheat. Selected isolates were
shown to release cytokinin and indole-3-acetic acid (IAA) by using UPLC coupled with MS/MS via an electrospray interface.
The maximum cytokinin and IAA concentration was 22.7 pmol mg−1 ch-a and 38 pmol mg−1 ch-a, respectively, in the culture medium of Chroococcidiopsis sp. Ck4 and Anabaena sp. Ck1. The growth of wheat inoculated with cyanobacterial strains was stimulated under axenic as well as field conditions.
Seed germination, shoot length, tillering, number of lateral roots, spike length, and grain weight were significantly enhanced
in inoculated plants. The maximum increase in grain weight (43%) was demonstrated in wheat plants inoculated with Chroococcidiopsis sp. Ck4 under natural conditions. Positive linear correlation of cyanobacterial cytokinin with shoot length (r = 0.608; P = 0.01), spike length (r = 0.682; P = 0.01), and grain weight (r = 0.0.869; P = 0.01) was recorded. Similarly, cyanobacterial IAA was correlated with the root growth parameters shoot length (r = 0.588; P = 0.01), spike length (r = 0.0.689; P = 0.01), and weight of seeds (r = 0.480; P = 0.05). The endogenous phytohormones pool of the plant was enhanced significantly as a result of the plant–cyanobacteria
association in the rhizosphere. It was concluded that cyanobacterial phytohormones are a major tool for improved growth and
yield in wheat. 相似文献
8.
Rodrigo O. Marañón Claudio M. Joo Turoni Alfredo Coviello María Peral de Bruno 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(4):403-409
Little is known about the vascular actions of angiotensin II (Ang II) and nitric oxide (NO) in Amphibia. This study investigated
(1) Ang II contractility, (2) NO concentrations, and (3) correlations between Ang II contractility, NO concentration and mean
arterial pressure (MAP) in isolated Bufo arenarum toad aortic rings. Contractility was measured in isometric conditions, NO concentrations were determined by the Griess reaction,
and MAP was determined by a direct method. In isolated toad aortic rings, Ang II produced a contractile response (292.7 ± 89.2 mg;
n = 20). Furthermore, a contractile response to norepinephrine (NE) was also obtained. A significant correlation between both
the Ang II and NE contractile responses was found (r = 0.89; n = 11; P < 0.01). Administration of Ang II increased MAP values (Basal 16.8 ± 1.7; n = 19 vs. Ang II 28.4 ± 1.8 mmHg; n = 19; P < 0.001), and the increase of MAP by Ang II was positively correlated with the Ang II contractile response (P < 0.01). Administration of L-NAME also increased MAP values, and this effect was higher in those toads that presented a lower
pressure response to Ang II (Pearson r = −0.68; P < 0.05). NO was present in all aortic rings, and its concentrations were negatively related to the Ang II contractile response
(P < 0.036) and pressure response (Pearson r = −7.08; P < 0.001). These findings suggest that, in the B. arenarum toad, the NO system contra-regulates both the contractile and pressure Ang II responses, although its action could be different
in each specimen. 相似文献
9.
Xiang ZL Zeng ZC Fan J Tang ZY He J Zeng HY Chang JY 《Molecular biology reports》2012,39(2):2021-2029
The purpose of this study was to evaluate the relationship between hypoxia-inducible factor-1α (HIF-1α) protein expression
in hepatocellular carcinoma (HCC), and responses of abdominal metastatic lymph nodes (LNs) from HCC patients treated with
external beam radiotherapy (EBRT). HIF-1α immunohistochemical staining was performed on tissue microarrays (TMAs) of primary
HCC specimens from 69 HCC patients with abdominal LN metastases. All patients received abdominal metastatic LN EBRT at the
Department of Radiation Oncology at Zhongshan Hospital. A receiver-operating characteristic (ROC)-based approach and logistical
regression analysis were used to determine the predictive value of HIF-1α expression in primary tumors with HCC metastatic
LN EBRT response. Kaplan–Meier curves and log-rank tests were used to analyze patient survival. Cox proportional hazards regression
model was used to analyze independent prognostic factors. HIF-1α expression was correlated with blood hemoglobin (Hb: r = −0.280, P = 0.020), response of abdominal metastatic LNs to EBRT (r = 0.286, P = 0.017), locoregional recurrence (r = 0.278, P = 0.021), and cancer-specific deaths (r = 0.298, P = 0.013). HIF-1α expression was predictive of EBRT response of metastatic LNs [area under the curve (AUC): 0.646; 95% confidence
interval (CI): 0.499–0.793; P = 0.047], locoregional recurrence (AUC: 0.657; 95% CI: 0.509–0.805; P = 0.049) and cancer-specific deaths (AUC: 0.671; 95% CI: 0.531–0.812; P = 0.035). Patients with tumors exhibiting high HIF-1α expression had significantly poorer overall survival (OS) than those
with low tumor expression of HIF-1α (P = 0.016). Multivariate analysis showed that Hb (P = 0.035), vascular invasion (P = 0.026), Child-Pugh score (P < 0.001), intrahepatic tumor control (P < 0.001), and HIF-1α (P = 0.020) were independent prognosis factors for OS of HCC patients after receiving abdominal metastatic LN EBRT. HIF-1α expression
in primary HCCs was associated with EBRT response of abdominal metastatic LNs and poor prognosis. 相似文献
10.
Iron plaque formation on wetland plants and its influence on phosphorus,calcium and metal uptake 总被引:7,自引:0,他引:7
We investigated Fe plaque formation and Ca, Cu, Mn, Zn, and P uptake capacities of fifteen kinds of wetland plants. The test
plants were cultured in 3 l nutrient solutions for 8 days. Fe plaque was induced by adding 200 mg l−1 Fe2+ as FeSO4·7H2O for 4 days in one set of experiment and 8 days in another. This plaque ranged from 2.38 to 8.67 mg g−1 of plant root after 4 days and from 4.56 to 15.71 mg g−1 of plant root after 8-day treatment. In both experimental durations, the plaque was significantly correlated with root surface
area (r = 0.904 and 0.878, P < 0.01). Thus, Canna generalis, Typha latifolia and Thalia dealbata, with their larger root surface areas (>1,400 cm2), formed relatively greater Fe plaque amounts. The amounts of Ca, Cu, Zn and P in the Fe plaques were significantly correlated
with Fe plaque amount, (r = 0.819, 0.742, 0.693, 0.917, respectively, for these four elements for the 4-day treatment; and r = 0.917, 0.768, 0.949, 0.872, respectively, for 8-day treatment, P < 0.01). Plants varied widely in accumulating Ca, Cu, Mn, Zn, and P in their tissues. The amounts accumulated on root were
significantly correlated with Fe plaque amount in both for 4- and 8-day exposure treatments with Fe (r = 0.973, 0.847, 0.709, 0.837, 0.892, respectively, for 4-day treatment; and r = 0.943, 0.691, 0.843, 0.957, 0.983, respectively, for 8-day treatment, P < 0.01). No such significant correlations were found for the Fe plaque in shoot. Canna generalis, Typha latifolia and Thalia dealbata were superior in Ca, P and Zn uptake, while Canna generalis and Thalia dealbata accumulated Cu and Mn well in case of concentrated wastewater treatment. 相似文献
11.
Basharat Ali Anjum Nasim Sabri Karin Ljung Shahida Hasnain 《World journal of microbiology & biotechnology》2009,25(3):519-526
Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene
sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml−1
L-tryptophan ranges from 0.60 to 3.0 μg IAA ml−1 as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more
IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic
conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production
by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated
Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata. 相似文献
12.
Thomas Miedaner Peter Risser Sophie Paillard Thorsten Schnurbusch Beat Keller Lorenz Hartl Josef Holzapfel Viktor Korzun Erhard Ebmeyer H. Friedrich Utz 《Molecular breeding : new strategies in plant improvement》2012,29(3):731-742
Septoria tritici blotch (STB), caused by S. tritici, Stagonospora glume blotch (SGB), caused by S. nodorum, and Fusarium head blight (FHB), caused by F. graminearum and F. culmorum, are the most important diseases of wheat (Triticum aestivum L.) in temperate growing areas. The main goals of this study were to detect (1) new quantitative trait loci (QTL) for STB
resistance in two adapted European biparental populations (Arina/Forno, History/Rubens) and (2) QTL regions for broad-spectrum
resistance (BSR) to the above-mentioned diseases during the adult-plant stage in the field. The three resistances were phenotyped
across 4–7 field environments and phenotypic data revealed significant (P < 0.01) genotypic differentiation in all cases. Entry-mean heritabilities (h2) ranged from 0.73 to 0.93. For STB resistance, correlations between disease ratings and heading date were significant (P < 0.01), but moderate (r = −0.23 to −0.30) in both populations. Correlations between STB and plant height were higher in Arina/Forno (r = −0.45) and History/Rubens (r = −0.55), the latter population segregating at the Rht-D1 locus. During the initial QTL analysis, 5 QTL were detected for STB resistance in each of the populations, amounting to an
explained genotypic variance of 45–63%, thus, showing the same ranges as FHB and SGB resistances in Arina/Forno and FHB resistance
in History/Rubens. In total, 7 BSR QTL were found in the meta-analysis with the raw data, including the QTL on chromosome
4D at the Rht-D1 locus. A BSR QTL for all three diseases was not found but several BSR QTL for combinations with two diseases were detected.
Combining the BSR QTL detected in the present breeding material by applying marker-assisted selection seems a promising approach. 相似文献
13.
S. Canpolat N. Tug A. D. Seyran S. Kumru B. Yilmaz 《Journal of physiology and biochemistry》2010,66(1):23-28
This study was designed to investigate effects of raloxifene (RLX) and estradiol on bone formation and resorption in intact
and ovariectomized (ovx) rat models. In the intact model, a total of 24 adult female rats were divided into three groups:
Controls subcutaneously received saline alone. RLX (2 mg/kg) and estradiol (30 μg/kg) were injected to two groups of animals
for a period of 6 weeks at two daily intervals. In the second model, rats (n = 24) were ovx and allowed to recover for a period of at least 3 weeks. Control group received vehicle alone. Remaining rats
were divided into two groups and injected with RLX (2 mg/kg) and estradiol (30 μg/kg) for 6 weeks. Urine samples were collected
from all animals 24 h after the last drug administration. Urinary deoxypyridinoline (DPD) was measured by ELISA. Serum parathyroid
hormone (PTH), calcitonin, and osteocalcin levels were measured by immunoradiometric method. Serum concentrations of alkaline
phosphatase (ALP), Ca, and inorganic phosphate were determined by enzymatic–colorimetric method. Lumbar vertebrae (L2) of
all animals were dissected out and processed for histopathological evaluation. Removal of ovaries significantly elevated urinary
DPD levels (p < 0.01) compared with intact controls. Treatment of both intact and ovx rats with estradiol resulted in significant decreases
(p < 0.01) in DPD values. RLX administration had no significant effect in the intact rats, but it remarkably reduced bone turnover
in the ovx animals (p < 0.001). Both estradiol and RLX produced conflicting effects on serum ALP, osteocalcin, and PTH levels in both animal models.
These findings suggest that RLX exerts its protective effects by reducing bone resorption, similar to that of estradiol, in
ovx rats. 相似文献
14.
Saadat M 《Molecular biology reports》2009,36(6):1353-1356
Objectives It is reported that parental exposure to toxicants can influence offspring sex ratio at birth. Studies have reported that
several chemicals found in cigarette smoke are substrates of glutathione S-transferase T1 (GSTT1, a member of GSTθ). To determine
the effect of cigarette smoke on serum levels of testosterone and gonadotrophins of smokers and possible association of these
hormones levels with GSTT1 polymorphism, the present study was done. Methods Our study was conducted on 181 (40 smokers, 141 non-smokers) male subjects. Genomic DNA was extracted from peripheral blood.
The GSTT1 genotyping was performed using PCR-based method. All measurements for testosterone, follicle stimulating hormone (FSH), and
luteinizing hormone (LH) were done in one laboratory. Results In smoker subjects the mean ± sd of serum testosterone, FSH, and LH were 4.64 ± 1.63 ng/ml, 2.72 ± 1.17 IU/l, and 3.03 ± 1.04 IU/l,
respectively. In non-smoker subjects the mean ± sd of serum testosterone, FSH, and LH were 4.49 ± 1.24 ng/ml, 2.89 ± 1.26 IU/l,
and 3.07 ± 1.28 IU/l, respectively. There was no significant difference between smokers and non-smokers for serum testosterone
(t = 0.622, df = 179, P = 0.535), FSH (t = −0.757, df = 179, P = 0.450), and LH (t = −0.179, df = 179, P = 0.858). Also there was no significant difference between smokers and non-smokers in either GSTT1 null or positive genotypes for levels of testosterone, FSH, and LH. Conclusion Based on present data, it might be concluded that serum levels of testosterone and gonadotrophins were not significantly
different between smoker and non-smoker males in both null and present GSTT1 genotypes. 相似文献
15.
Miloslav Devetter 《Aquatic Ecology》2009,43(1):85-89
Bdelloid rotifers are basal consumers in aquatic and limnoterrestrial communities that feed primarily on small bacteria. Unfortunately,
we know only a little of the role they play in the trophic dynamics in some unusual habitats they inhabit. Habrotrocha thienemanni is a typical example; it is a typical tree-hole inhabitant, commonly achieving dense populations. Filtering rates of H. thienemanni were estimated using fluorescent microspheres of a size close to natural bacterial community (0.5 μm in diameter) at two
temperatures (15 and 20°C). This microspheres artificial food had been coated with BSA protein. Mean clearance rates of this
rotifer varied between 1.65 and 3.79 μl ind−1 h−1 under different temperatures. Uptake of particles coated with protein was significantly higher than that on uncoated particles
(t = 2.85; P = 0.005). Particle uptake also was correlated to the body size of the animal (r = 0.44; P = 0.004,). The clearance rate of the natural H. thienemanni population (56,800 ind l−1) ranged from 981 to 5170 ml l−1 d−1. 相似文献
16.
Desert plants have unique strategies for survival and growth to cope with the limited water availability in arid regions.
The stable carbon isotope (δ
13C) provides an integrated measurement of internal plant physiological and external environmental properties affecting photosynthetic
gas exchange and water use efficiency. The δ
13C values of 84 species in the Junggar Basin were categorized into two groups (ranged from −30.1 to −23.3‰ for C3 and −14.9 to −9.9‰ for C4 species, respectively). No life form differences in δ
13C values were detected in C3 (p = 0.78) and C4 plants (p = 0.63). Small differences among life forms were observed in δ
13C values in C4 species with shrubs slightly depleted (−13.3‰) relative to perennials (−13.1‰) and annuals (−12.5‰). These differences suggested
that δ
13C value could not represent a plant functional group classification based on life forms in C4 plants in extremely arid regions. Ephemerals are all using C3 photosynthetic pathway and no significant differences (p = 0.92) in δ
13C values were observed between annuals (−26.5‰) and perennials (−26.4‰). The δ
13C values of Tulipa iliensis (an important ephemeral species distributed widely in the Junggar Basin) among nine natural populations were positively correlated
with leaf (r
2 = 0.46, p = 0.046) and soil (r
2 = 0.67, p = 0.007) total nitrogen content, and negatively correlated with leaf (r
2 = 0.48, p = 0.039) and soil (r
2 = 0.79, p = 0.001) water content. This indicated that the variation in δ
13C values of T. iliensis was probably caused by both water availability associated stomatal openness and nitrogen availability associated photosynthetic
capacity. T. iliensis is very sensitive to water and nitrogen availability in soil. 相似文献
17.
HRT preserves increases in bone mineral density and reductions in body fat after a supervised exercise program 总被引:3,自引:0,他引:3
Kohrt Wendy M.; Ehsani Ali A.; Birge Stanley J. Jr. 《Journal of applied physiology》1998,84(5):1506-1512
The aims of thisstudy were to confirm our previous finding that hormone-replacementtherapy (HRT) augments exercise-induced increases in bone mineraldensity (BMD) in older women and to determine whether HRT preserves theadaptations when exercise is reduced or discontinued. The studyincluded an 11-mo treatment phase and a 6-mo follow-up phase.Participants, aged 66 ± 3 yr, were assigned to control (Con;n = 10), exercise (Ex;n = 18), HRT(n = 10), and Ex+HRT(n = 16) groups. HRT was continuedduring the follow-up. After the treatment phase, changes in total body BMD were 0.5 ± 1.7, 1.5 ± 1.4, 1.2 ± 0.8, and 2.7 ± 1.2% in Con, Ex, HRT, and Ex+HRT, respectively. Ex+HRT was moreeffective than HRT in increasing BMD of the total body and tended(P = 0.08) to be more effective at thelumbar spine. Ex+HRT was more effective than Ex in increasing BMD ofthe total body, lumbar spine, and trochanter. Exercise-induced gains inBMD were preserved during the follow-up only in those individuals onHRT. HRT also attenuated fat accumulation, particularly in theabdominal region, after the exercise program. These findings suggestthat HRT is an important adjunct to exercise for the prevention notonly of osteoporosis but also of diseases related to abdominal obesity. 相似文献
18.
Recent studies have identified common variants in or near GC, CYP2R1 and NADSYN1/DHCR7 to be associated with 25-hydroxyvitamin D [25(OH)D] levels in European populations. We aimed to examine whether these variants
also influence 25(OH)D levels in Chinese. Seven common variants were successfully genotyped and tested for associations with
plasma 25(OH)D levels in a population-based cohort of 3,210 Chinese Hans from Beijing and Shanghai. Six common variants at
GC (rs4588, rs7041, rs2282679 and rs1155563) and NADSYN1/DHCR7 (rs3829251 and rs1790349) loci were all significantly associated with lower plasma 25(OH)D levels (−0.036 ≤ β ≤ −0.076 per risk-allele, P ≤ 5.7 × 10−5), while CYP2R1-rs2060793 showed a trend toward association with 25(OH)D levels in the Shanghai subpopulation (P = 0.08), but not in the Beijing subpopulation (P = 0.82). Haplotype-based association analyses of the four GC variants showed that only the haplotype that contained all risk-alleles (TACC) was significantly associated with lower plasma
25(OH)D levels (β = −0.085, P = 2.3 × 10−9), while the haplotype containing the risk-alleles of rs4588 and rs2282679 (TATC) was marginally associated with lower 25(OH)D
levels (β = −0.054, P = 0.0562) when compared with GCTA haplotype carrying the four protective alleles. Most notably, conditional analyses showed
that only GC-rs4588 and GC-rs2282679 (r
2 = 0.97) remained significantly associated with 25(OH)D concentrations (P ≤ 1.9 × 10−5) after adjusting for the other two SNPs in GC. In conclusion, GC and NADSYN1/DHCR7 loci individually and collectively contribute to variation in plasma vitamin D levels in Chinese Hans. 相似文献
19.
Barton HJ 《Biological trace element research》2011,143(2):637-658
The population of about 300 6-year-old preschool children was studied for lead (Pb) and cadmium (Cd) in deciduous teeth, scalp
hair, and capillary blood. Zinc (Zn) content in hair was also measured due to its possible interferences with the elements
studied. The Pb and Cd contents were measured by graphite furnace atomic absorption spectrometry with Zeeman background correction,
and Zn, by flame method. Metal levels found were comparable to those in European countries. Positive correlations between
Pb and Cd in the same and different tissues were widespread (r = 0.23–0.68). A positive correlation was found between Pb in teeth and blood (r = 0.65, p < 0.001). Pb blood threshold 100 μg L−1 referred to 2.6 μg g−1 Pb in teeth. Predictability of this Pb teeth limit was 14% vs. 5% for Pb blood. Strong negative correlation was found between
hair Pb and Zn (r = −0.68, p < 0.001). Enhanced Cd and Zn levels in hair were associated with the household drinking water hardness. The associations
with some other environmental and behavioral factors were also presented and discussed. The results proved the advantage of
analysis of primary teeth for Pb exposure screening of preschool children. 相似文献
20.
Piotr Piotrowski Robert Gasik Margarita Lianeri Dorota Cieślak Mariusz Wudarski Paweł Hrycaj Jan K. Łącki Paweł P. Jagodziński 《Molecular biology reports》2010,37(1):235-239
Endogenous sex hormones have been observed to have a role in systemic lupus erythematosus (SLE) predisposition. Sex hormone-binding
globulin (SHBG) regulates the bioavailability of sex hormones to target tissues. Therefore, we examined the distribution of
the SHBG functional polymorphism Asp327Asn (rs6259) in SLE patients (n = 150) and controls (n = 150) in a Polish population. We found a contribution of the SHBG327Asn variant to the development of SLE. Women with the Asp/Asn and Asn/Asn genotypes displayed a 2.630-fold increased risk of
SLE (95% CI = 1.561–4.433, P = 0.0003). SHBG has a much higher affinity for testosterone than estradiol, and the SHBG327Asn variant displays a reduction
of estradiol clearance. Therefore we suggest that the opposing effects of estrogens and testosterone on the immune system
and imbalance in the levels of these hormones in SLE patients can be enhanced by the SHBG327Asn protein variant. 相似文献