Litter age interacted with N and P addition to impact soil N2O emissions in Cunninghamia lanceolata plantations

凋落物年龄和氮、磷添加交互作用对杉木林土壤N₂O排放的影响 氧化亚氮(N₂O)是一种重要的温室气体，增温潜势较大，其浓度增加影响全球气候变化。由于凋落物分解影响碳和养分循环，土壤N₂O排放受凋落物分解作用，而凋落物年龄和氮、磷添加影响凋落物分解，潜在影响土壤N₂O的排放。然而，凋落物年龄和养分添加对土壤N₂O排放的交互作用及其机制目前还没有报道，这限制了凋落物分解对N₂O排放的影响评价。本研究以杉木(Cunninghamia lanceolata)不同年龄凋落物为研究对象，通过氮、磷添加处理，研究了养分和凋落物年龄对N₂O排放的影响及其机制。研究结果显示，幼龄凋落物主要通过调节碳氮比来影响N₂O排放。氮添加主要通过调节凋落物碳氮比、土壤pH以及与N₂O产生相关的微生物功能基因所编码的土壤酶活性来影响N₂O排放，整体上促进N₂O排放。磷添加显著降低凋落物碳氮比，进而作用于N₂O排放，该途径促进N₂O排放。同时，磷添加提高土壤有效磷水平，潜在降低N₂O排放，整体上降低土壤N₂O排放。凋落物年龄和养分添加交互作用于土壤N₂O排放。因此，在森林经营管理中，评价不同管理措施，尤其是间伐和选择性砍伐等导致不同凋落物输入的管理活动对土壤N₂O排放的影响时，应同时考虑养分输入和凋落物年龄的潜在影响。     

Human huntingtin-associated protein (HAP-1) gene: genomic organisation and an intragenic polymorphism

The huntingtin-associated protein (HAP-1) interacts with the Huntington disease gene product, huntingtin. It is predominantly expressed in the brain and shows an increased affinity for mutant huntingtin. We have sequenced an 18,656bp genomic region encompassing the entire human HAP-1 gene and determined its genomic organisation, with 11 exons spanning 12.1kb. We have also found an intragenic polymorphism within intron 6 of HAP-1. We have recently shown that HAP-1 maps to a region of the genome which has been implicated in a variety of neurological conditions, including progressive supranuclear palsy (PSP), a late-onset atypical parkinsonian disorder. The detailed characterisation of the genomic organisation of HAP-1 and the presence of an intragenic polymorphism will be helpful in evaluating its role in different disorders, using candidate gene approaches.     

Association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and essential hypertension in young Pakistani patients

Several studies have demonstrated the importance of angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphisms in the pathogenesis of hypertension. This study sought to determine the association between the ACE I/D polymorphism and essential hypertension in young Pakistanis. The frequency of the ACE I/D polymorphism was established by a comparative cross-sectional survey of Pakistani patients suffering from essential hypertension and ethnically matched normotensive controls. Samples were collected from tertiary care hospitals in northern Pakistan. Hypertensive individuals were defined as those with a systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg on three separate occasions, or those currently receiving one, or more, anti-hypertensive agents. DNA samples obtained from hypertensive (n = 211) and normotensive (n = 108) individuals were typed by PCR. The frequency of the ACE I/I genotype was significantly higher in hypertensive patients, aged 20-40 years, than in normotensive controls of the same age group (chi(2) = 4.0, P = 0.041). Whereas no overall significant differences were observed between the I/I, I/D and D/D ACE genotypes (One way ANOVA, F = 0.672; P = 0.413). The association between the ACE I/I genotype and essential hypertension in individuals aged 相似文献   

Paraptosis: mediation by MAP kinases and inhibition by AIP-1/Alix

Programmed cell death (pcd) may take the form of apoptotic or nonapoptotic pcd. Whereas cysteine aspartyl-specific proteases (caspases) mediate apoptosis, the mediators of nonapoptotic cell death programs are much less well characterized. Here, we report that paraptosis, an alternative, nonapoptotic cell death program that may be induced by the insulin-like growth factor I receptor (among other inducers), is mediated by mitogen-activated protein kinases (MAPKs) and inhibited by AIP-1/Alix. The inhibition by AIP-1/Alix is specific for paraptosis since apoptosis was not inhibited. Caspases were not activated in this paradigm, nor were caspase inhibitors effective in blocking cell death. However, insulin-like growth factor I receptor (IGFIR)-induced paraptosis was inhibited by MEK-2-specific inhibitors and by antisense oligonucleotides directed against c-jun N-terminal kinase-1 (JNK-1). These results suggest that IGFIR-induced paraptosis is mediated by MAPKs, and inhibited by AIP-1/Alix.     

Frcp1 and Frcp2, two novel fibronectin type III repeat containing genes

The fibronectin type III (FNIII) repeat is one of three structural motifs originally identified in the fibronectin protein and has been well characterized in recent years. The consensus sequence has since been found in many different proteins including receptors and cell adhesion molecules. We report the cloning and expression analysis of Frcp1 and Frcp2, two members of a new FNIII repeat containing gene family. During embryonic development both genes are primarily expressed in the brain. In adult tissues, Frcp1 is strongly expressed in the liver and Frcp2 in the heart.     

Testing the use of specimen collection data and GIS in biodiversity exploration and conservation decision making in Guyana

This paper presents the results of a study conducted at the request of the Government of Guyana by the Centre for the Study of Biological Diversity at the University of Guyana, and the Smithsonian Institution. The purpose of the study was to evaluate the utility of using systematic collections in identifying areas with a high priority for conservation. A biodiversity database and a gazetteer were assembled and interpreted primarily through the use of maps generated in ARC/INFO and ArcView. The data were examined to determine coverage and completeness, and while in general the results support a continued use of the methodology for making informed decisions in conservation related issues, several recommendations are offered in order to enhance the data. The primary use of the results of this study is in the identification of areas of interest for conservation and in the location of eleven areas covering most ecoregions in Guyana that are in need of additional study. The eleven areas have been chosen to avoid areas that are already allocated to logging and mining concessions or Amerindian lands. While it is true that this study would benefit from additional data and further analysis of those data, it is also true that decisions concerning areas for conservation in Guyana are being made in the near future, and if any data are to be used in this process, it will be those data presented in this paper.     

Towards thermally stable cyclophanediene-dihydropyrene photoswitches

Cyclophanediene dihydropyrenes (CPD-DHP) are photochromic compounds because they change their color by irradiation with lights of different color. Potential use of CPD-DHP photoswitch in memory devices requires a very slow thermal return in the dark in the absence of any side reaction. Herein, thermal return of CPDs to DHPs, and an unwanted sigmatropic shift in DHP is studied through density functional theory calculations at (U)B3LYP/6-31+G(d). The thermal return occurs through symmetry forbidden conrotatory electrocyclic reaction. Dimethyl amino CPD-DHP photoswitch pair has the highest activation barrier for electrocyclization and sigmatropic shifts. The lowest activation barrier for symmetry forbidden electrocyclization is observed for GeBr₃ functionalized CPD. An unprecedented decomposition pathway involving elimination of the internal substituents is predicted for Cl, Br and SMe functionalized DHPs. This study shows great promise in understanding the Woodward Hoffmann forbidden processes and, in reducing the synthetic efforts toward robust photochromes for memory applications.