首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The presence of Kv1.3 voltage-gated potassium channels in rat and human prostate epithelial cells has been previously reported. We examined, by immunohistochemistry, Kv1.3 levels in 10 normal human prostate, 18 benign prostatic hyperplasia (BPH) and 147 primary human prostate cancer (Pca) specimens. We found high epithelial expression of Kv1.3 in all normal prostate, 16 BPH and 77 (52%) Pca specimens. Compared to normal, Kv1.3 levels were reduced in 1 (6%) BPH specimen and in 70 (48%) Pca specimens. We found a significant inverse correlation between Kv1.3 levels and tumor grade (r = -0.25, P = 0.003) as well as tumor stage (r = -0.27, P = 0.001). Study of an additional 30 primary Pca specimens showed that 15 (50%) had reduced Kv1.3 immunostaining compared to matched normal prostate tissue. Our data suggest that in Pca reduced Kv1.3 expression occurs frequently and may be associated with a poor outcome.  相似文献   

2.
3.
4.
Expression of the N-methyl-D-aspartate receptor (NMDAr) and its involvement in cellular proliferation is well-known in tumors of neuronal tissue, such as glioma and neuroblastoma. We have investigated NMDAr expression in the normal, hyperplastic and neoplastic human prostate by immunohistochemistry. Low stromal NMDAr immunostaining was observed in 2 of 12 (17%) normal prostate specimens, but epithelial NMDAr staining was not seen. Of 18 benign prostatic hyperplasia (BPH) specimens, none had stromal NMDAr staining, but 2 had low and 1 had high epithelial NMDAr immunoreactivity. Moderate to high NMDAr immunostaining was observed in the stroma of 60 of 145 (41%) prostate cancer (PCa) specimens. Epithelial NMDAr staining was low in 26 (18%) and moderate to high in 36 (25%) of 145 PCa specimens. We have also examined the effects of the NMDAr antagonist memantine on the growth of ten human cancer cell lines: four prostate, two breast and four colon. The NMDAr antagonist memantine inhibited in-vitro growth of all ten cell lines, with half-maximal growth-inhibition at 5 to 20 μg/ml (23 to 92 μM) memantine. An NMDA agonist, L-cysteinesulfinic acid, stimulated cellular proliferation of all ten cell lines, with maximal growth-stimulation (30% to 75%, depending on the cell line) observed between doses of 33 to 66 μM. Our data provide evidence for the expression and activity of NMDAr in prostate cancer.  相似文献   

5.
Androgens and estrogens, acting via their respective receptors, are important in benign prostatic hyperplasia (BPH). The goals of this study were to quantitatively characterize the tissue distribution and staining intensity of androgen receptor (AR) and estrogen receptor-alpha (ERα), and assess cells expressing both AR and ERα, in human BPH compared to normal prostate. A tissue microarray composed of normal prostate and BPH tissue was used and multiplexed immunohistochemistry was performed to detect AR and ERα. We used a multispectral imaging platform for automated scanning, tissue and cell segmentation and marker quantification. BPH specimens had an increased number of epithelial and stromal cells and increased percentage of epithelium. In both stroma and epithelium, the mean nuclear area was decreased in BPH relative to normal prostate. AR expression and staining intensity in epithelial and stromal cells was significantly increased in BPH compared to normal prostate. ERα expression was increased in BPH epithelium. However, stromal ERα expression and staining intensity was decreased in BPH compared to normal prostate. Double positive (AR and ERα) epithelial cells were more prevalent in BPH, and fewer double negative (AR and ERα) stromal and epithelial negative cells were observed in BPH. These data underscore the importance of tissue layer localization and expression of steroid hormone receptors in the prostate. Understanding the tissue-specific hormone action of androgens and estrogens will lead to a better understanding of mechanisms of pathogenesis in the prostate and may lead to better treatment for BPH.  相似文献   

6.
The voltage-gated potassium channel, Kv1.3, which is highly expressed in a number of immune cells, contains concensus sites for phosphorylation by protein kinase C (PKC). In lymphocytes, this channel is involved in proliferation—through effects on membrane potential, Ca2+ signalling, and interleukin-2 secretion—and in cytotoxic killing and volume regulation. Because PKC activation (as well as increased intracellular Ca2+) is required for T-cell proliferation, we have studied the regulation of Kv1.3 current by PKC in normal (nontransformed) human T lymphocytes. Adding intracellular ATP to support phosphorylation, shifted the voltage dependence of activation by +8 mV and inactivation by +17 mV, resulting in a 230% increase in the window current. Inhibiting ATP production and action with ``death brew' (2-deoxyglucose, adenylylimidodiphosphate, carbonyl cyanide-m-chlorophenyl hydrazone) reduced the K+ conductance (G K ) by 41 ± 2%. PKC activation by 4β-phorbol 12,13-dibutyrate, increased G K by 69 ± 6%, and caused a positive shift in activation (+9 mV) and inactivation (+9 mV), which resulted in a 270% increase in window current. Conversely, several PKC inhibitors reduced the current. Diffusion into the cell of inhibitory pseudosubstrate or substrate peptides reduced G K by 43 ± 5% and 38 ± 8%, respectively. The specific PKC inhibitor, calphostin C, potently inhibited Kv1.3 current in a dose- and light-dependent manner (IC50∼ 250 nm). We conclude that phosphorylation by PKC upregulates Kv1.3 channel activity in human lymphocytes and, as a result of shifts in voltage dependence, this enhancement is especially prevalent at physiologically relevant membrane potentials. This increased Kv1.3 current may help maintain a negative membrane potential and a high driving force for Ca2+ entry in the presence of activating stimuli. Received: 12 July 1996/Revised: 21 October 1996  相似文献   

7.
The Kv1.3 protein is a member of the large family of voltage‐dependent K+ subunits (Kv channels), which assemble to form tetrameric membrane‐spanning channels that provide a selective pore for the conductance of K+ across the cell membrane. Kv1.3 differs from most other Kv channels in that deletion of Kv1.3 gene produces very striking changes in development and structure of the olfactory bulb, where Kv1.3 is expressed at high levels, resulting in a lower threshold for detection of odors, an increased number of synaptic glomeruli and alterations in the levels of a variety of neuronal signaling molecules. Because Kv1.3 is also expressed in the cerebral cortex, we have now examined the effects of deletion of the Kv1.3 gene on the expression of interneuron populations of the cerebral cortex. Using unbiased stereology we found an increase in the number of parvalbumin (PV) cells in whole cerebral cortex of Kv1.3?/? mice relative to that in wild‐type mice, and a decrease in the number of calbindin (CB), calretinin (CR), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and somatostatin (SOM) interneurons. These changes are accompanied by a decrease in the cortical volume such that the cell density of PV interneurons is significantly increased and that of SOM neurons is decreased in Kv1.3?/? animals. Our studies suggest that, as in the olfactory bulb, Kv1.3 plays a unique role in neuronal differentiation and/or survival of interneuron populations and that expression of Kv1.3 is required for normal cortical function. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73:841–855, 2013  相似文献   

8.
9.
Whole cell perforated patch-clampexperiments were performed with adult rat alveolar epithelial cells.The holding potential was 60 mV, and depolarizing voltage stepsactivated voltage-gated K+ (Kv) channels. Thevoltage-activated currents exhibited a mean reversal potential of 32mV. Complete activation was achieved at 10 mV. The currents exhibitedslow inactivation, with significant variability in the time coursebetween cells. Tail current analysis revealed cell-to-cell variabilityin K+ selectivity, suggesting contributions of multiple Kv-subunits to the whole cell current. The Kv channels also displayedsteady-state inactivation when the membrane potential was held atdepolarized voltages with a window current between 30 and 5 mV.Analysis of RNA isolated from these cells by RT-PCR revealed thepresence of eight Kv -subunits (Kv1.1, Kv1.3, Kv1.4, Kv2.2, Kv4.1,Kv4.2, Kv4.3, and Kv9.3), three -subunits (Kv1.1, Kv2.1, andKv3.1), and two K+ channel interacting protein (KChIP)isoforms (KChIP2 and KChIP3). Western blot analysis with available Kv-subunit antibodies (Kv1.1, Kv1.3, Kv1.4, Kv4.2, and Kv4.3) showedlabeling of 50-kDa proteins from alveolar epithelial cells grown inmonolayer culture. Immunocytochemical analysis of cells from monolayersshowed that Kv1.1, Kv1.3, Kv1.4, Kv4.2, and Kv4.3 were localized to theapical membrane. We conclude that expression of multiple Kv -, -,and KChIP subunits explains the variability in inactivation gating andK+ selectivity observed between cells and that Kv channelsin the apical membrane may contribute to basal K+ secretionacross the alveolar epithelium.

  相似文献   

10.
Because of a lack of information of the optimum nutritional requirements, epithelial cells derived from normal human prostate and prostate tumors have been difficult to propagate in vitro, which hinders research in prostate carcinogenesis. In an effort to establish optimum nutritional conditions and differences in growth characteristics of normal human prostate (NP), benign prostatic hyperplasia (BPH), and prostatic carcinoma (PCA), we have compared the effects of several growth factors on cell proliferation and elucidated growth properties of low passage epithelial cells derived from NP, BPH, and PCA of an African-American patient. Primary and low passage cultures were propagated in serum-free keratinocyte basal medium (KBM) supplemented with insulin (5 μg/ml), hydrocortisone (0.5 μg/ml), epidermal growth factor (EGF, 10 ng/ml), bovine pituitary extract (BPE; 50 μg/ml), cholera toxin (10 ng/ml), and antibiotics. Almost all NP, BPH, and PCA cells were positive for cytokeratins and prostate-specific antigen (PSA). The NP, BPH, and PCA cells were essentially diploid and lacked mutations in c-K-ras and c-Ha-ras oncogenes, and p53 tumor suppressor gene. However, they exhibited progressively accelerating growth parameters. The population doubling times of NP, BPH and PCA were 51 hr, 37 hr, and 29 hr, respectively; their saturation densities were 2.9 × 104/cm2, 3.3 × 104/cm2, and 7.2 × 104/cm2, respectively. The NP and BPH cells required all of the growth factors in the medium, as deletion of any one of the above factors strongly inhibited their growth. The PCA cells, however, were independent of EGF and hydrocortisone. PC-3, an established human prostate cancer cell line, was independent of the growth factors tested. Fetal bovine serum (FBS) inhibited the growth of NP, BPH and PCA cells. In contrast, FBS stimulated the growth of the PC-3 cells in a concentration-dependent manner. These results indicate that in the absence of any apparent karyotype alterations and mutations in c-K-ras, c-Ha-ras and p53 genes, epithelial cells derived from NP, BPH, and PCA exhibit significant differences in their growth properties and responses to growth factors. These variations may represent early changes involved in prostate cancer, while gene mutations and cytogenetic alterations occur in advanced and/or metastatic tumors. © 1996 Wiley-Liss, Inc.  相似文献   

11.
Cardiovascular diseases (CVD) constitute a significant risk and may, in part, explain the high morbidity and mortality rates among haemodialysis (HD) patients. Several studies have implicated reduced insulin like growth factor (IGF-1) levels in the development of CVD. However, it is not clear whether IGF-1, and its relationship with other hormones such as leptin, insulin, and growth hormone (GH), as well as anthropometric variables may explain the high incidence of vascular complications in chronic kidney disease (CKD) patients. This study was designed to measure total serum IGF-1, leptin, insulin and GH levels in CKD patients and in age-matched control subjects and to elucidate the relationship between IGF-1 and GH, leptin, and insulin as well as other known aetiological risk factors for CVD including blood pressure, body mass index (BMI), and age. The study consisted of 50 CKD patients [36 M and 14 F; mean age; 41.8 ± 10.3 years) on maintenance haemodialysis and 50 healthy control subjects (36 M and 14 F; mean age 41.6 ± 10.2 years) matched for age and sex. None of the subject among patients and controls reported either smoking or history of diabetes mellitus. The circulating levels of IGF-1 were significantly lower (P < 0.001) in both male and female patients compared to the control subjects. Moreover, IGF-1 was strongly and inversely correlated with both systolic blood pressure (SBP) (r = −0.360; P < 0.01) and diastolic blood pressure (DBP) (r = −0.512; P < 0.001) in the CKD group, and when the two groups were combined SBP (r = −0.396; P < 0.001) and DBP (r = −0.296; P < 0.01). When adjusted for age, the correlation was more significant, however, when adjusted for BMI no significant correlation was observed between IGF-1 and blood pressure. IGF-1 was inversely correlated with age (r = −0.367; P < 0.01) and BMI (r = −0.310; P < 0.05) in the control group, but not the patient group. In controls and patients, respectively, a positive correlation between leptin and BMI (r = 0.358; P < 0.01; r = 0.640, P < 0.001) was observed. The results show that circulating levels of IGF-1 were significantly lower in CKD patients as compared to healthy normal subjects and were inversely correlated with SBP and DBP independent of age, but not BMI indicative of a strong relationship between cardiovascular risk factors and low IGF-1 levels. Although, the data do not clearly indicate low IGF-1 levels as a cause or an effect of these cardiovascular risk factors, they do point to an interesting relationship between low IGF-1 levels and increased cardiovascular risk factors among CKD patients as compared to age-matched healthy control subjects.  相似文献   

12.
The therapeutic potential of IFN-gamma in prostatic cancer has been documented in several reports, although no immunohistochemical studies of this factor and its receptors in the prostate have been reported. The aim of the present study was to investigate the expression of IFN-gamma and its receptor components (IFN-gamma-Ralpha and IFN-gamma-Rbeta) in normal prostate, benign prostatic hyperplasia (BPH) and prostatic cancer (PC), as well as the possible relationship between this factor and the products of the p53 gene (the wild and mutant forms) and the oncogene c-myc, by means of immunochemical techniques (Western blot, ELISA, and quantification of immunostaining in histological sections). In normal prostate, IFN-gamma and its two receptors were expressed in the basal cells of the epithelium and some stromal cells. In BPH specimens, immunostaining of basal epithelial cells was significantly increased for IFN-gamma and its a receptor, whereas stromal cell immunostaining was significantly increased for IFN-gamma and its b receptor. In addition, columnar epithelial cells immunostained for IFNbeta-Rbeta. PC specimens differed from BPH specimens in the significantly increased immunostaining of epithelial cells for IFN-gamma and its two receptors, and the immunostaining of columnar epithelial cells for IFN-gamma-Ralpha. Immunodetection of wild-p53 was weak and limited to some stromal cells in the three types of specimens. Immunostainings for both mutant-p53 and c-myc were negative in normal prostate, and positive in the epithelium and stromal cells of both BPH and PC specimens. Immunostaining intensity in PC was significantly higher than in BPH. These observations suggest that the expression of both mutant-p53 and c-myc, together with other factors, might be involved in the development of prostatic hyperplasia and neoplasia, while the increased expression of IFN-gamma and its receptors could be regarded as an attempt, although insufficient, to inhibit the uncontrolled cell proliferation.  相似文献   

13.
The choroid plexuses secrete, and maintain the composition of, the cerebrospinal fluid. K+ channels play an important role in these processes. In this study the molecular identity and properties of the delayed-rectifying K+ (Kv) conductance in rat choroid plexus epithelial cells were investigated. Whole cell K+ currents were significantly reduced by 10 nM dendrotoxin-K and 1 nM margatoxin, which are specific inhibitors of Kv1.1 and Kv1.3 channels, respectively. A combination of dendrotoxin-K and margatoxin caused a depolarization of the membrane potential in current-clamp experiments. Western blot analysis indicated the presence of Kv1.1 and Kv1.3 proteins in the choroid plexus. Furthermore, the Kv1.3 and Kv1.1 proteins appear to be expressed in the apical membrane of the epithelial cells in immunocytochemical studies. The Kv conductance was inhibited by 1 µM serotonin (5-HT), with maximum inhibition to 48% of control occurring in 8 min (P < 0.05 by Student's t-test for paired data). Channel inhibition by 5-HT was prevented by the 5-HT2C antagonist mesulergine (300 nM). It was also attenuated in the presence of calphostin C (a protein kinase C inhibitor). The conductance was partially inhibited by 1,2-dioctanoyl-sn-glycerol and phorbol 12-myristate 13-acetate, both of which activate protein kinase C. These data suggest that 5-HT acts at 5-HT2C receptors to activate protein kinase C, which inhibits the Kv channels. In conclusion, Kv1.1 and Kv1.3 channels make a significant contribution to K+ efflux at the apical membrane of the choroid plexus. delayed-rectifying potassium channel; serotonin  相似文献   

14.
Uncontrolled epithelial cell proliferation in the prostate transition zone and the hyper-accumulation of mesenchymal-like cells derived from the epithelial-mesenchymal transition (EMT) of prostatic epithelium are two key processes in benign prostatic hyperplasia (BPH). m6A RNA modification affects multiple cellular processes, including cell proliferation, apoptosis, and differentiation. In this study, the aberrant up-regulation of methylase METTL3 in BPH samples suggests its potential role in BPH development. Elevated m6A modification in the prostate of the BPH rat was partially reduced by METTL3 knockdown. METTL3 knockdown also partially reduced the prostatic epithelial thickness and prostate weight, significantly improved the histological features of the prostate, inhibited epithelial proliferation and EMT, and promoted apoptosis. In vitro, METTL3 knockdown decreased TGF-β-stimulated BPH-1 cell proliferation, m6A modification, and EMT, whereas promoted cell apoptosis. METTL3 increased the m6A modification of PTEN and inhibited its expression through the reading protein YTHDF2. PTEN knockdown aggravated the molecular, cellular, and pathological alterations in the prostate of BPH rats and amplified TGF-β-induced changes in BPH-1 cells. More importantly, PTEN knockdown partially abolished the improving effects of METTL3 knockdown both in vivo and in vitro. In conclusion, the level of m6A modification is elevated in BPH; the METTL3/YTHDF2/PTEN axis disturbs the balance between epithelial proliferation and apoptosis, promotes EMT, and accelerates BPH development in an m6A modification-related manner.Subject terms: Cell biology, Molecular biology  相似文献   

15.
Leptin, the obesity gene protein product, is a hormone with multiple physiological functions in the human. However, there are few reports in the literature on its role in trace element metabolism in the normal population. Therefore, we investigated the association among serum leptin, zinc, copper, and zinc/copper ratio in 570 healthy men and women aged 15 yr and older. Serum leptin assay was done with a commercial enzymelinked immunosorbent assay kit; serum zinc and copper levels were measured by an atomic absorption spectrophotometer. Serum leptin was found to be positively associated with age (r=0.254, p<0.001), sex (r=0.406, p<0.001), body mass index (BMI) (r=0.553, p<0.001), and serum copper (r=0.419, p<0.001), but negatively associated with the zinc/copper ratio (r=−0.423, p<0.001). There was no significant association between serum leptin and zinc (r=−0.131, p>0.05). When the confounding effects of age, sex, and BMI were removed, serum leptin was still positively associated with serum copper (r=0.197, p=0.02) and the serum zinc/copper ratio (r=−0.182, p=0.03). These results suggest that copper and not zinc has an effect on serum leptin levels.  相似文献   

16.
Kallikarein-related peptidase 3 (KLK3) gene polymorphisms seem to play a role in susceptibility to prostate cancer (PC). The purpose of this study was to investigate the association between rs2735839 polymorphism of KLK3 gene and risk of PC in an Iranian population. In this case-control study, rs2735839 was genotyped in 532 patients with PC and 602 controls with benign prostate hyperplasia (BPH) using polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of GG, AG, and AA genotypes of KLK3 polymorphism was 24.6% and 76.2%, 46.6% and 21.7%, and 28.8% and 2.1%, in patients with BPH and PC, respectively (P < 0.001). The frequency of G allele in patients with BPH and PC was 47.9% and 87%, respectively (odds ratio: 7.31; confidence interval: 5.88-9.10; P < 0.001). Patients with AG and GG genotypes had a higher total serum level of prostate-specific antigen (PSA) compared to those with AA genotype (P < 0.001). Patients with this polymorphism had higher risk of tumor with higher grade (P = 0.23), advanced stage (P = 0.11), perineural invasion (P = 0.07), and vascular invasion (P = 0.07) compared to those without it but this difference was not statistically significant. Based on our results, KLK3 gene polymorphism was associated with the risk of PC. Higher levels of PSA in the presence of KLK3 polymorphism in patients with PC indicated that rs2735839 polymorphism could be a risk factor for increased levels of PSA.  相似文献   

17.
The Shaker-type voltage-gated potassium channel, Kv1.3, is believed to be restricted in distribution to lymphocytes and neurons. In lymphocytes, this channel has gained intense attention since it has been proven that inhibition of Kv1.3 channels compromise T lymphocyte activation. To investigate possible expression of Kv1.3 channels in other types of tissue, such as epithelia, binding experiments, immunoprecipitation studies and immunohistochemical studies were performed. The double-mutated, radiolabeled peptidyl ligand, 125I-HgTX1-A19Y/Y37F, which selectively binds Kv1.1, Kv1.2, Kv1.3 and Kv1.6 channels, was used to perform binding studies in epithelia isolated from rabbit kidney and colon. The equilibrium dissociation constant for this ligand was found to be in the sub-picomolar range and the maximal receptor concentration (in fmol/mg protein) 1.68 for colon and 0.61-0.75 for kidney epithelium. To determine the subtype of Kv1 channels, immunoprecipitation studies with 125I-HgTX1-A19Y/Y37F labeled epithelial membranes were performed with specific antibodies against Kv1.1, Kv1.2, Kv1.3, Kv1.4 or Kv1.6 subunits. These studies demonstrated that Kv1.3 subunits constituted more than 50% of the entire Kv1 subunit population. The precise localization of Kv1.3 subunits in epithelia was determined by immunohistochemical studies.  相似文献   

18.
Zinc and cadmium analysis in human prostate neoplasms   总被引:4,自引:0,他引:4  
The objective of this study was to test the hypothesis that prostatic cancer is associated with the changes of zinc (Zn) and cadmium (Cd) concentration. Normal prostate, benign prostatic hyperplasia (BPH), and prostatic carcinoma (PCA) were analyzed for Zn and Cd by atomic absorption spectrometry. Cd level was measured using a graphite furnace and Zn level was measured by flame mode. Metal content was assessed in whole tissues and in nuclear, plasma membrane, and cytosolic fractions. An increase of Zn content in BPH, but a decrease in PCA as compared to normal tissue, was observed. Cd concentration appeared to be higher in BPH and PCA than in normal tissue. No correlation between Zn and Cd level was found in BPH specimens obtained from the same patients. Probability values ofp ≤0.05 were considered to indicate significant differences. Obtained results seem to support the hypothesis of Cd carcinogenicity and preventing function of Zn in prostatic cancer. Plasma membrane fraction corresponding to lysosomal, mitochondrial, and microsomal subcellular compartments are probably critical in Zn and Cd participation in human prostate neoplasms.  相似文献   

19.
Benign prostatic hyperplasia (BPH) is the most common adenoma in old men. Tomatoes are a rich source of bioactive compounds that, as well as selenium (Se), possess antioxidant and antiproliferative activity. The aim was to evaluate the therapeutic effect of Se in combination with a tomato extract in aged rats with BPH. Aged male Wistar rats were divided in the following groups (n = 10 rats/group): Control (C), BPH, BPH + Finasteride (BPH + F), BPH + Tomato Lipidic Extract (BPH + E), BPH + Selenium (BPH + S) and BPH plus E plus S (BPH + E + S). After 4 weeks of treatment, prostate weight, diuresis, antioxidants enzymes, prooxidants and inflammatory markers, growth factors and androgens were determined. BPH + E + S reduced prostate weight by 59.29% and inhibited growth by 99.35% compared to BPH + F which only decreased weight and inhibited growth by 15.31% and 57.54%, respectively. Prooxidant markers were higher with BPH + F (49.4% higher vs. BPH), but BPH + E + S decreased these markers (94.27% vs. BPH) and increased antioxidant activity. Finally, diuresis was higher with the BPH + E + S combination and markers of inflammation and growth factors were significantly lower with respect to BPH + F. Our findings provide a beneficial and protective therapeutic option of E + S directed against androgens, oxidative stress and inflammation that regulates cell proliferation in the prostate gland.  相似文献   

20.
This study examines distributional patterns of benthic diatom assemblages in relation to environmental characteristics in streams and rivers in the California Central Valley ecoregion. Benthic diatoms, water quality, and physical habitat conditions were characterized from 53 randomly selected sites. The stream sites were characterized by low mid-channel canopy cover and high channel substrate embeddedness. The waters at these sites were enriched with minerals and turbidity varied from 1.3 to 185.0 NTU with an average of 13.5 NTU. A total of 249 diatom taxa were identified. Average taxa richness was 41 with a range of 7–76. The assemblages were dominated by Staurosira construens (11%), Epithemia sorex (8%), Cocconeis placentula (7%), and Nitzschia amphibia (6%). Multivariate analyses (cluster analysis, classification tree analysis, and canonical correspondence analysis) all showed that benthic diatom assemblages were mainly affected by channel morphology, in-stream habitat, and riparian conditions. The 1st CCA axis negatively correlated with mean wetted channel width (r = −0.66) and thalweg depth (r = −0.65) (Table 4). The 2nd axis correlated with % coarse substrates (r=0.60). Our results suggest that benthic diatoms can be used for assessing physical habitat alterations in streams.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号