Effect of nutrient level on competition intensity in the field for three coexisting grass species

A field experiment encompassing both neighbour- and nutrient-manipulations was conducted in a nutrient-impoverished old-field habitat to investigate how the intensity of plant competition was affected by soil nutrient level. Three perennial grasses were used as target species: Agropyron repens, Poa pratensis and Phleum pratense. Neighbour manipulations involved the removal (through herbicide application) of all neighbouring vegetation within a 20 cm or 40 cm radius around target plants. Target performance was measured under five levels of added nutrients (N-P-K) in both the neighbour-removal plots and in non-removal (control) plots. Both neighbour and nutrient manipulations had a highly significant effect on both biomass and tiller production but the interaction between these treatments was generally insignificant. Below-ground/above-ground biomass quotient was affected only by neighbour manipulations and was greatest in the control plots (with no neighbours removed) for all three species. The suppressive effect of neighbours was not markedly affected by nutrient level. However, yield suppression showed a significant decreasing trend with increasing nutrient level for biomass production in Agropyron and an increasing trend for tiller production in Phleum. For Poa, there was no trend in the intensity of competition across nutrient level. The results suggest that the general intensity of competition within this community neither increases nor decreases with increasing nutrient level. Rather, coexisting species appear to respond individually in terms of the intensity of competition that they experience. These results conflict with predictions from the triangular C-S-R model of plant strategies. However, they are consistent with a recently modified ‘habitat templet’ model for vegetation.     

一个以前列腺特异抗原密度和穿刺评分为基础的中国人群中前列腺癌根治术后病理升级预测模型的建立

目的：分析前列腺癌根治术后病理得分较穿刺得分增加的原因，并建立一个可以预测中国人群中前列腺癌根治术后病理升 级的模型。方法：以2008 年8 月至2013 年12 月在我院泌尿科行前列腺癌根治性切除术的264例患者的临床资料为基础，根据 术前和术后患者病理得分的变化将其分为升级组和未升级组。运用单因素和多因素logistic 回归分析病理升级的原因，并通过多 因素回归系数建立预测病理升级的诺模图。结果：264 例患者中，共238 例最终纳入统计分析，多因素logistic 回归分析显示前列 腺特异抗原密度(0R=3.854，P=0.001 )和穿刺Gleason(≤ 6)评分是中国人群中前列腺癌根治术后病理升级的独立危险因素。前列腺 特异抗原密度和穿刺得分的ROC 最佳截断取值为0.37 ng/ml 2和8 分。运用上述两个变量建立了一个可用于预测病理升级的诺 模图。结论：前列腺特异抗原密度和穿刺Gleason 评分是预测中国人群中前列腺癌根治术后病理升级的独立危险因素，本研究所 得的诺模图可以很好地预测前列腺癌根治术后的病理升级。     

Sirtuin 5 regulates the proliferation,invasion and migration of prostate cancer cells through acetyl‐CoA acetyltransferase 1

Sirtuin 5 (SIRT5) is a NAD⁺‐dependent class III protein deacetylase, and its role in prostate cancer has not yet been reported. Therefore, to explore the diagnosis and treatment of prostate cancer, we investigated the effect of SIRT5 on prostate cancer. Sirtuin 5 was assessed by immunohistochemistry in 57 normal and cancerous prostate tissues. We found that the tissue expression levels of SIRT5 in patients with Gleason scores ≥7 were significantly different from those in patients with Gleason scores <7 (P < .05, R > 0). Further, mass spectrometry and pathway screening experiments showed that SIRT5 regulated the activity of the mitogen‐activated protein kinase (MAPK) pathway, which in turn modulated the expression of MMP9 and cyclin D1. Being a substrate of SIRT5, acetyl‐CoA acetyltransferase 1 (ACAT1) was regulated by SIRT5. SIRT5 also regulated MAPK pathway activity through ACAT1. These results revealed that SIRT5 promoted the activity of the MAPK pathway through ACAT1, increasing the ability of prostate cancer cells to proliferate, migrate and invade. Overall, these results indicate that SIRT5 expression is closely associated with prostate cancer progression. Understanding the underlying mechanism may provide new targets and methods for the diagnosis and treatment of the disease.     

PSA密度对前列腺癌病理结果的预测价值

目的:评估前列腺特异抗原密度(prostate specific antigen density,PASD)对前列腺癌根治术后不良病理结果的预测价值.方法:回顾性分析50例病理确诊为前列腺癌患者的临床资料,收集患者术前总前列腺特异抗原(total prostate specific antigen,tPSA)、PSAD及穿刺活检Gleason评分结果,比较在手术切缘阳性(positive surgical margins,PSM)、前列腺包膜外侵犯(extracapsular prostatic extension,EPE)、精囊入侵(seminal vesicle invasion,SVI)患者中以上各项指标的差异,对有统计学差异的因素行多元Logistic回归分析,筛选影响浸润的最主要因素,同时运用工作特征曲线(ROC曲线)比较各指标的预测价值.结果:PSM,EPE和SVI患者之间PSAD存在统计学差异,PSAD曲线下面积高于PSA与Gleason评分.多元Logistic回归分析结果表明,PSAD和Gleason评分对PSM和EPE有着统计学意义的预测价值,且PSAD和PSA与SVI有关.结论:PSAD可作为接受前列腺癌根治术的患者术后不良的预测指标.     

An update analysis of two polymorphisms in encoding ribonuclease L gene and prostate cancer risk: involving 13,372 cases and 11,953 controls

Encoding ribonuclease L (RNASEL) is a ubiquitously expressed latent endoribonuclease involved in the mediation of antiviral and pro-apoptotic activities of the interferon-inducible 2-5A system. Although the relationship between RNASEL gene polymorphisms and prostate cancer (PCa) risk has been widely reported, results were somewhat controversial and underpowered. Now, we performed an update analysis of 14 publications evaluating the association between RNASEL R462Q and D541E polymorphisms and PCa risk. We conducted a literature search of PubMed database to identify all eligible articles that examined the association of RNASEL R462Q and D541E polymorphisms with PCa. Odds ratios (OR) with 95% confidence intervals (CI) were estimated to assess these association. R462Q showed a significantly elevated effect on Africans (QQ vs. RR: OR = 2.50, 95% CI = 1.28–4.87, P_{heterogeneity} = 0.231). In addition, PCa men who contain 462Q genotype had a higher Gleason score ≥ 7 (OR = 1.16, 95% CI = 1.05–1.28, P_{heterogeneity} = 0.906). On the other hand, D541E was associated with increased total PCa. In the stratified analysis by race, there was also significantly increased PCa in Africans and Caucasians, as well as in sporadic PCa studies (OR = 1.09, 95% CI = 1.04–1.15, P_{heterogeneity} = 0.078). Our update analysis showed evidence that RNASEL R462Q and D541E polymorphisms were associated with PCa risk. Still more well-designed studies should be performed to clarify the role of these two polymorphisms in the development of PCa.     

Correlation of protein expression, Gleason score and DNA ploidy in prostate cancer

The prognosis of prostate cancer correlates with tumor differentiation. Gleason score and DNA ploidy are two prognostic factors that correlate with prognosis. We analyzed differences in protein expression in prostate cancer of high and low aggressiveness according to these measures. From 35 prostatectomy specimens, 29 cancer samples and 10 benign samples were harvested by scraping cells from cut surfaces. DNA ploidy was assessed by image cytometry. Protein preparations from cell suspensions were examined by 2-DE. Protein spots that differed quantitatively between sample groups were identified by MS fingerprinting of tryptic fragments and MS/MS sequence analysis. We found 39 protein spots with expression levels that were raised or lowered in correlation with Gleason score and/or DNA ploidy pattern (31 overexpressed in high-malignant cancer, 8 underexpressed). Of these, 30 were identified by MS. Among overexpressed proteins were heat-shock, structural and membrane proteins and enzymes involved in gene silencing, protein synthesis/degradation, mitochondrial protein import (metaxin 2), detoxification (GST-pi) and energy metabolism. Stroma-associated proteins were generally underexpressed. The protein expression of prostate cancer correlates with tumor differentiation. Potential prognostic markers may be found among proteins that are differentially expressed and the clinical value of these should be validated.     

Species-area relations in a New Zealand tussock grassland,with implications for nature reserve design and for community structure

Abstract. A tussock grassland, in Blackrock Reserve, New Zealand, was sampled thoroughly at scales ranging from 0.01 m x 0.01 m to 20 m x 20 m, to investigate species-area relations of relevance to plant community structure, and to offer a pointer to reserve design. In total, 96 species were found. Of the native vascular species among these, 20% were new records for the reserve. For the total and the native vascular flora the observed points fell midway between the Arrhenius and Gleason fitted curves. Cryptogams fitted the Arrhenius model well, with z close to the 0.26 value expected for isolates under Preston's Canonical hypothesis. Extrapolation of the Arrhenius curve to the whole of the New Zealand uplands gave values far too large; the Gleason curve gave values much too low. A General Root model is introduced. It fits the observed species richnesses at various quadrat sizes considerably better than previous models. When biogeographic limitations on species richness are included, extrapolation of the General Root curve accurately predicts the size of the upland flora. This fit, the lack of an asymptote, and the rarity structure, are compatible with a random and individualistic model of community structure. However, there are differences in species-area relation between vascular and cryptogamic plants, which cautions against expecting any universal type of community structure. Extrapolations using the General Root model suggest that if the ideal is a 10 km x 10 km reserve, a reserve one tenth that size would contain 81% of the native species in that ideal, and the present Blackrock Reserve contains 67%.     

Temporal variation in the woody understory of an old-growth Fagus-Acer forest and implications for overstory recruitment

Abstract. Changes in woody vegetation were examined over eight years, using a 1.05-ha permanent plot in which the location of every shrub and tree > 1m height was mapped. There was little change in the overstory vegetation, as expected for an old-growth forest. Much greater change occurred in the understory, primarily related to a 40 % increase in density. Differences occurred among species in the under-story, as Acer saccharum and Prunus serotina increased and Fraxinus americana and Fagus grandifolia decreased. Canopy gap dynamics are implicated in differences among species in the establishment and growth of individuals in the understory and their recruitment into the overstory. It is concluded that because understory is temporally variable, overstory recruitment from the understory may take different courses at different times in the same forest.     

Four decades of old field vegetation development and the role of Celastrus orbiculatus in the northeastern United States

Abstract. This paper describes four decades of in situ vegetation change in a post-agricultural site in southern New England where the role of the introduced vine, Celastrus orbiculatus, has drastically modified the course of vegetation development. An initial perennial forb-grassland community was replaced by two strikingly different physiognomic vegetation types-an early hardwood forest and a vine community occupying the same site 40 yr later. This ecological phenomenon was unpredictable since Celastrus was not recorded at the site until the 1970s. Within the young hardwood forest dominated by Prunus serotina and Acer rubrum, a few old field species (five) persist, whereas 17 forest herbs have become established. Typical forest shrubs are rare or absent. The Celastrus-dominated vine community has suppressed or eliminated pre-existing growth to form a relatively stable community where a forest vegetation is the regional vegetation type. Celastrus also appears to be facilitating a native vine (Vitis labrusca) by forming a ‘ladder’ for its advance. Although A. rubrum and Quercus spp. could ultimately dominate the forest community, the contiguous and aggressive nature of Celastrus makes predictions questionable. This long-term study highlights the unpredictable nature of old field succession and the role of an exotic species in threatening the natural vegetation development.