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21.
One of the main drivers of tropical forest loss is their conversion to oil palm, soy or cacao plantations with low biodiversity and greatly reduced carbon storage. Southeast Asian cacao plantations are often established under shade tree cover, but are later converted to non-shaded monocultures to avoid resource competition. We compared three co-occurring cacao cultivation systems (3 replicate stands each) with different shade intensity (non-shaded monoculture, cacao with the legume Gliricidia sepium shade trees, and cacao with several shade tree species) in Sulawesi (Indonesia) with respect to above- and belowground biomass and productivity, and cacao bean yield. Total biomass C stocks (above- and belowground) increased fivefold from the monoculture to the multi-shade tree system (from 11 to 57 Mg ha-1), total net primary production rose twofold (from 9 to 18 Mg C ha-1 yr-1). This increase was associated with a 6fold increase in aboveground biomass, but only a 3.5fold increase in root biomass, indicating a clear shift in C allocation to aboveground tree organs with increasing shade for both cacao and shade trees. Despite a canopy cover increase from 50 to 93%, cacao bean yield remained invariant across the systems (variation: 1.1–1.2 Mg C ha-1 yr-1). The monocultures had a twice as rapid leaf turnover suggesting that shading reduces the exposure of cacao to atmospheric drought, probably resulting in greater leaf longevity. Thus, contrary to general belief, cacao bean yield does not necessarily decrease under shading which seems to reduce physical stress. If planned properly, cacao plantations under a shade tree cover allow combining high yield with benefits for carbon sequestration and storage, production system stability under stress, and higher levels of animal and plant diversity.  相似文献   
22.
Restenosis represents a major impediment to the success of coronary angioplasty. Abnormal proliferation of vascular smooth muscle cells (VSMCs) has been shown to be an important process in the pathogenesis of restenosis. A number of agents, particularly rapamycin and paclitaxel, have been shown to impact on this process. This study was carried out to determine the mechanisms of cytotoxicity of goniothalamin (GN) on VSMCs. Results from MTT cytotoxicity assay showed that the IC(50) for GN was 4.4 microg/ml (22 microM), which was lower compared to the clinically used rapamycin (IC(50) of 25 microg/ml [27.346 microM]). This was achieved primarily via apoptosis where up to 25.83 +/- 0.44% of apoptotic cells were detected after 72 h treatment with GN. In addition, GN demonstrated similar effects as rapamycin in inhibiting VSMCs proliferation using bromodeoxyuridine (BrdU) cell proliferation assay after 72 h treatment at IC(50) concentration (p > 0.05). In order to understand the mechanisms of GN, DNA damage detection using comet assay was determined at 2h post-treatment with GN. Our results showed that there was a concentration-dependent increase in DNA damage in VSMCs prior to cytotoxicity. Moreover, GN effects were comparable to rapamycin. In conclusion, our data show that GN initially induces DNA damage which subsequently leads to cytotoxicity primarily via apoptosis in VSMCs.  相似文献   
23.
Mental retardation (MR) has a worldwide prevalence of around 2% and is a frequent cause of severe disability. Significant excess of MR in the progeny of consanguineous matings as well as functional considerations suggest that autosomal recessive forms of MR (ARMR) must be relatively common. To shed more light on the causes of autosomal recessive MR (ARMR), we have set out in 2003 to perform systematic clinical studies and autozygosity mapping in large consanguineous Iranian families with non-syndromic ARMR (NS-ARMR). As previously reported (Najmabadi et al. in Hum Genet 121:43-48, 2007), this led us to the identification of 12 novel ARMR loci, 8 of which had a significant LOD score (OMIM: MRT5-12). In the meantime, we and others have found causative gene defects in two of these intervals. Moreover, as reported here, tripling the size of our cohort has enabled us to identify 27 additional unrelated families with NS-ARMR and single-linkage intervals; 14 of these define novel loci for non-syndromic ARMR. Altogether, 13 out of 39 single linkage intervals observed in our cohort were found to cluster at 6 different loci on chromosomes, i.e., 1p34, 4q27, 5p15, 9q34, 11p11-q13 and 19q13, respectively. Five of these clusters consist of two significantly overlapping linkage intervals, and on chr 1p34, three single linkage intervals coincide, including the previously described MRT12 locus. The probability for this distribution to be due to chance is only 1.14 × 10(-5), as shown by Monte Carlo simulation. Thus, in contrast to our previous conclusions, these novel data indicate that common molecular causes of NS-ARMR do exist, and in the Iranian population, the most frequent ones may well account for several percent of the patients. These findings will be instrumental in the identification of the underlying genes.  相似文献   
24.
BackgroundThe sequencing of two members of the Royal Kelantan Malay family genomes will provide insights on the Kelantan Malay whole genome sequences. The two Kelantan Malay genomes were analyzed for the SNP markers associated with thalassemia and Helicobacter pylori infection. Helicobacter pylori infection was reported to be low prevalence in the north-east as compared to the west coast of the Peninsular Malaysia and beta-thalassemia was known to be one of the most common inherited and genetic disorder in Malaysia.ResultBy combining SNP information from literatures, GWAS study and NCBI ClinVar, 18 unique SNPs were selected for further analysis. From these 18 SNPs, 10 SNPs came from previous study of Helicobacter pylori infection among Malay patients, 6 SNPs were from NCBI ClinVar and 2 SNPs from GWAS studies. The analysis reveals that both Royal Kelantan Malay genomes shared all the 10 SNPs identified by Maran (Single Nucleotide Polymorphims (SNPs) genotypic profiling of Malay patients with and without Helicobacter pylori infection in Kelantan, 2011) and one SNP from GWAS study. In addition, the analysis also reveals that both Royal Kelantan Malay genomes shared 3 SNP markers; HBG1 (rs1061234), HBB (rs1609812) and BCL11A (rs766432) where all three markers were associated with beta-thalassemia.ConclusionsOur findings suggest that the Royal Kelantan Malays carry the SNPs which are associated with protection to Helicobacter pylori infection. In addition they also carry SNPs which are associated with beta-thalassemia. These findings are in line with the findings by other researchers who conducted studies on thalassemia and Helicobacter pylori infection in the non-royal Malay population.  相似文献   
25.
The aim of the present study was to investigate the binding sites interactions and the selectivity of sarpogrelate to human 5-HT(2) receptor family (5-HT(2A), 5-HT(2B) and 5-HT(2C) receptor subtypes) using molecular modeling. Rhodopsin (RH) crystal structures were used as template to build structural models of the human serotonin-2A and -2C receptors (5-HT(2A)R, 5-HT(2C)R), whereas for 5-HT(2B)R, we used our previously published three-dimensional (3D) models based on bacteriorhodopsin (BR). Sarpogrelate, a novel 5-HT(2)R antagonist, was docked to the receptors. Molecular dynamics (MD) simulations produced the strongest interaction for 5-HT(2A)R/sarpogrelate complex. Upon binding, sarpogrelate constraints aromatic residues network (Trp(3.28), Phe(5.47), Trp(6.48), Phe(6.51), Phe(6.52) in 5-HT(2A)R; Phe(3.35), Phe(6.51), Trp(7.40) in 5-HT(2B)R; Trp(3.28), Phe(3.35), Phe(5.47), Trp(6.48), Phe(6.51), Phe(6.52) in 5-HT(2C)R) in a stacked configuration, preventing activation of the receptor. The models suggest that the structural origin of the selectivity of sarpogrelate to 5-HT(2A)R vs both 5-HT(2B)R and 5-HT(2C)R comes from the following results: (1) The tight interaction between the antagonist and the transmembrane domain (TMD) 3. Asp(3.32) neutralizes the cationic head and interacts simultaneously with carboxylic group hydrogen of the antagonist molecule. (2) Due to steric hindrance, Ser(5.46) (vs Ala(5.46) in 5HT(2B) and 5HT(2C)) prevents sarpogrelate to enter deeply inside the hydrophobic core of the helix bundle and to interact with Pro(5.50). (3) The side chain of Ile(4.56) (vs Ile(4.56) in 5HT(2B)R and Val(4.56) in 5HT(2C)R) constraints sarpogrelate to adjust its position by translating toward the strongly attractive Asp(3.32). These results are in good agreement with binding affinities (pKi) of sarpogrelate for 5-HT(2) receptor family expressed in transfected cell.  相似文献   
26.
Despite recent advances in understanding the genetic bases of microcephaly, a large number of cases of microcephaly remain unexplained, suggesting that many microcephaly syndromes and associated genes have yet to be identified. Here, we report mutations in PYCR2, which encodes an enzyme in the proline biosynthesis pathway, as the cause of a unique syndrome characterized by postnatal microcephaly, hypomyelination, and reduced cerebral white-matter volume. Linkage mapping and whole-exome sequencing identified homozygous mutations (c.355C>T [p.Arg119Cys] and c.751C>T [p.Arg251Cys]) in PYCR2 in the affected individuals of two consanguineous families. A lymphoblastoid cell line from one affected individual showed a strong reduction in the amount of PYCR2. When mutant cDNAs were transfected into HEK293FT cells, both variant proteins retained normal mitochondrial localization but had lower amounts than the wild-type protein, suggesting that the variant proteins were less stable. A PYCR2-deficient HEK293FT cell line generated by genome editing with the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system showed that PYCR2 loss of function led to decreased mitochondrial membrane potential and increased susceptibility to apoptosis under oxidative stress. Morpholino-based knockdown of a zebrafish PYCR2 ortholog, pycr1b, recapitulated the human microcephaly phenotype, which was rescued by wild-type human PYCR2 mRNA, but not by mutant mRNAs, further supporting the pathogenicity of the identified variants. Hypomyelination and the absence of lax, wrinkly skin distinguishes this condition from that caused by previously reported mutations in the gene encoding PYCR2’s isozyme, PYCR1, suggesting a unique and indispensable role for PYCR2 in the human CNS during development.  相似文献   
27.
The use of oil-contaminated sand in building and construction is now being considered as an alternative and cost-effective way to minimize its adverse effect on the environment. To achieve this, the effect of oil contamination on the important mechanical properties of sand should be investigated first. This study investigated the effect of petroleum-derived contaminants on the water absorption, permeability, cohesion, friction angle, and shear strength of fine sand. Contaminated samples were prepared by mixing fine sand with different percentages of light crude oil (0 to 20%). The results indicated that the water absorption of fine sand decreases with an increase in crude oil. An increase in the cohesion was observed for sand with up to 1% of oil contamination, after which the cohesion began to decrease, which also results in the reduction in the permeability. A slight reduction in the friction angle was found for oil-contaminated fine sand. At a low normal stress of 50 kPa, as the percentage of light crude oil increased, the shear strength increased up to 1% of oil contamination and then it decreased. These results provided useful information on how oil-contaminated sand can be used safely and effectively in building and construction.  相似文献   
28.
Rajab  Yasmin Abou  Hölscher  Dirk  Leuschner  Christoph  Barus  Henry  Tjoa  Aiyen  Hertel  Dietrich 《Plant and Soil》2018,429(1-2):349-361
Plant and Soil - We examined the effect of downregulating PdKOR1 gene, an endo-β-1,4-glucanase gene family member previously characterized to affect cellulose biosynthesis and cell wall...  相似文献   
29.
The objective of this study is to introduce dynamic topography of surface electromyography (SEMG) to visualize lumbar muscle myoelectric activity and provides a new view to analyze muscle activity in vivo. A total of 20 healthy male subjects and 15 males LBP were enrolled. An electrode-array was applied to the lumbar region to collect SEMG. The root mean square (RMS) value was calculated for each channel, and then a 160×120 matrix was constructed using a linear cubic spline interpolation of each scan to create a 2-D color topographic image. Along a definite interval of action, a series of RMS topography matrices was concatenated as a function of position and time, to form a dynamic topographical video of lumbar muscle activity. Relative area (RA), relative width (RW), relative height (RH) and Width-to-Height Ratio (W/H) were chosen as the four quantitative parameters in measuring topographic features. Normal RMS dynamic topography was found to have a consistent, symmetric pattern with a high intensity area in the paraspinal area. LBP patients had a different RMS dynamic topography, with an asymmetric, broad, or disorganized distribution. Quantitative SEMG features were found significantly different between normal control and LBP. After physiotherapy rehabilitation, the dynamic topography images of LBP tended towards the normal pattern.There are obvious differences in lumbar muscle coordination between healthy subjects and LBP patients. The dynamic topography allows the continuous visualization of the distribution of surface EMG signals and the coordination of muscular contractions.  相似文献   
30.
Abstract

Reactions of α, α′-dichloroazo compounds 2 with SbCl5 gave 1-(chloroalkyl)-1-aza-2-azoniaallene salts 3 as reactive intermediates. Cycloadditions of 3 with the ribofuranosyl cyanide 4 afforded the β-D-ribofuranosyl-1,2,4-triazolium salts 5, which rearranged spontaneously to salts 6. Hydrolysis of 6 gave the 1,2,4-triazole C-nucleosides 7, which yielded the free nucleosides 8 after deblocking. Analogously, 12 was prepared from the cycloaddition of 4 with the α-chloroazo compound 10 in the presence of SbCl5. Deblocking of 12 with sodium methoxide afforded 13. Compounds 8a,b,e,f and 13 were tested against HIV-1, HIV-2, HSV-1 and HSV-2 and were found to be inactive.  相似文献   
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