On the causes of trends in the seasonal amplitude of atmospheric CO2

No consensus has yet been reached on the major factors driving the observed increase in the seasonal amplitude of atmospheric CO₂ in the northern latitudes. In this study, we used atmospheric CO₂ records from 26 northern hemisphere stations with a temporal coverage longer than 15 years, and an atmospheric transport model prescribed with net biome productivity (NBP) from an ensemble of nine terrestrial ecosystem models, to attribute change in the seasonal amplitude of atmospheric CO₂. We found significant (p < .05) increases in seasonal peak‐to‐trough CO₂ amplitude (AMP_P‐T) at nine stations, and in trough‐to‐peak amplitude (AMP_T‐P) at eight stations over the last three decades. Most of the stations that recorded increasing amplitudes are in Arctic and boreal regions (>50°N), consistent with previous observations that the amplitude increased faster at Barrow (Arctic) than at Mauna Loa (subtropics). The multi‐model ensemble mean (MMEM) shows that the response of ecosystem carbon cycling to rising CO₂ concentration (eCO₂) and climate change are dominant drivers of the increase in AMP_P‐T and AMP_T‐P in the high latitudes. At the Barrow station, the observed increase of AMP_P‐T and AMP_T‐P over the last 33 years is explained by eCO₂ (39% and 42%) almost equally than by climate change (32% and 35%). The increased carbon losses during the months with a net carbon release in response to eCO₂ are associated with higher ecosystem respiration due to the increase in carbon storage caused by eCO₂ during carbon uptake period. Air‐sea CO₂ fluxes (10% for AMP_P‐T and 11% for AMP_T‐P) and the impacts of land‐use change (marginally significant 3% for AMP_P‐T and 4% for AMP_T‐P) also contributed to the CO₂ measured at Barrow, highlighting the role of these factors in regulating seasonal changes in the global carbon cycle.     

Complete genome sequence of an H10N8 avian influenza virus isolated from a live bird market in Southern China

An H10N8 avian influenza virus (AIV), designated A/Duck/Guangdong/E1/2012 (H10N8), was isolated from a duck in January 2012. This is first report that this subtype of AIV was isolated from a live bird market (LBM) in Guangdong Province in southern China. Furthermore, the complete genome of this strain was analyzed. The availability of genome sequences is helpful to further investigations of epidemiology and molecular characteristics of AIV in southern China.     

Analysis of metabolic pathway using hybrid properties

Given a compounds-forming system, i.e., a system consisting of some compounds and their relationship, can it form a biologically meaningful pathway? It is a fundamental problem in systems biology. Nowadays, a lot of information on different organisms, at both genetic and metabolic levels, has been collected and stored in some specific databases. Based on these data, it is feasible to address such an essential problem. Metabolic pathway is one kind of compounds-forming systems and we analyzed them in yeast by extracting different (biological and graphic) features from each of the 13,736 compounds-forming systems, of which 136 are positive pathways, i.e., known metabolic pathway from KEGG; while 13,600 were negative. Each of these compounds-forming systems was represented by 144 features, of which 88 are graph features and 56 biological features. "Minimum Redundancy Maximum Relevance" and "Incremental Feature Selection" were utilized to analyze these features and 16 optimal features were selected as being able to predict a query compounds- forming system most successfully. It was found through Jackknife cross-validation that the overall success rate of identifying the positive pathways was 74.26%. It is anticipated that this novel approach and encouraging result may give meaningful illumination to investigate this important topic.     

不同降水条件下科尔沁沙地南缘疏林草地樟子松针叶δ13C和叶性状特征

通过比较不同自然降水年份(极端干旱和极端湿润)19年生疏林草地樟子松的针叶δ¹³C、比叶面积和干物质含量,结合土壤含水量和地下水埋深,探讨了极端降水对樟子松水分利用的影响.结果表明: 干旱年份(2009)樟子松林土壤含水量显著低于湿润年份(2010),但樟子松当年生针叶的δ¹³C在两年间没有显著差异,且两年相同月份间亦无显著差异;干旱年份当年生针叶的比叶面积显著低于湿润年份,而不同年份间干物质含量的差异不显著.在两种极端降水条件下,樟子松的水分利用效率没有明显变化,主要通过改变当年生针叶的比叶面积来适应降水量的变化.对于地下水埋深高于3.0 m的疏林草地樟子松人工林生态系统,极端干旱不会严重影响樟子松的存活和生长.     

Differential promoter activities of functional haplotypes in the 5′‐flanking region of human Sulfotransferase 1A1

Previously, we reported five common single nucleotide polymorphisms (SNPs), ?624G>C, ?396G>A, ?358A>C, ?341C>G, and ?294T>C, and six common haplotypes (CGACT, GAACT, GGAGC, GGACC, CAACT, and GAACC) in the 5′‐flanking region of the SULT1A1 gene that were associated with altered enzymatic activity. In the present study, we performed in vitro assays to determine the functional impact of these genetic variations on the promoter activity. Dual luciferase reporter assays revealed that these SNPs are located in a negative regulatory fragment of the SULT1A1 gene. Further experiments demonstrated that these SNPs and haplotypes affected promoter activities of SULT1A1. Electrophoretic mobility shift assays showed distinctive binding patterns for the SNPs ‐396G>A and ‐294T>C, due to differential binding affinities of the G/A alleles and the T/C alleles to nuclear proteins extracted from the liver carcinoma cell lines, HepG2 and Huh7. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:422–428, 2012; View this article online at wileyonlinelibrary.com . DOI 10:1002/jbt.21437     

Development of pig embryos by nuclear transfer of cultured fibroblast cells

Pig fibroblast cells were transferred to enucleated oocytes by micromanipulation and electrofusion. The donor cells used for nuclear transfer were synchronized in presumptive G0 by serum starvation. In the first experiment, nuclear transfer was performed with fibroblasts that had either a smooth or a rough surface. A significant difference (p < 0.05) in the percentage of chromosome condensation (39.5%, 15/38 and 16.6%, 5/30) and nuclear formation (36.8%, 14/38 and 16.3%, 8/49) was found between the reconstructed embryos derived from the cells with smooth surface and with rough surfaces, respectively. The percentage of chromosome condensation (42.5%, 17/40 and 19.6%, 11/56) and nuclear formation (38.3%, 23/60 and 18.8%, 9/48) were higher (p < 0.05) in reconstructed embryos derived from small (15 microm) donor cells compared to large donor cells (20 microm), respectively. The percentage nuclei at 3 different time points (3, 6, and 9 hours in culture medium) was higher (p = 0.003) in the reconstructed embryos activated by thimerosal and dithiothreitol (20%, 36%, and 41.3%) compared to those without activation treatment (0%, 11.8%, and 22.2%). In addition, there was an increased percentage with nuclei as the time in culture increased from 3 to 9 hours (p = 0.029). The percentages of chromosome condensation (34.6%; 9/26) and nuclear formation (33.3%; 9/27) in nuclear transfer embryos were similar. The rate of blastocysts/morulae development (14.0%; 6/43) was low. However, 2 cavitated embryos (presumptive blastocysts) with 14 and 11 nuclei and 1 morula with 8 nuclei were obtained. This together with the above evidence indicate that the nuclei from pig fibroblast cells can be partially reprogrammed, which suggests that transfer of nuclei from fibroblast cells to in vitro matured oocytes resulting in production of identical or genetically altered pigs may be possible.     

中国新栎盾蚧属一新种及二新纪录种(同翅目:蚧总科:盾蚧科)

记述新栎盾蚧属Neoquernaspis Howell et Takagi,1981一新种,即细管新栎盾蚧N.leptosipha sp.nov和2种中国分布新纪录种,即石柯新栎盾蚧N.beshearae Liu et Tippins,1988和尼泊尔新栎盾蚧N.nepalensis (Takagi,1977),并编制了该属中国已知种类检索表,新种模式标本和新纪录标本保存于西北农业大学昆虫博物馆。     

The specific binding activities of human urinary radioiodinated colony-stimulating factor-1 to various human tissue cells

1. Colony-stimulating factor (CSF-1) was isolated from a large volume of fresh normal human urine by 5 steps of purification and enrichment. 2. The purification factor is 100,000 fold and the purified compound exhibits a 2.16 x 10(7) U/mg of protein sp. act. 3. The isolated CSF-1 is a sialoglycoprotein with 41.5% of carbohydrate. The almost complete removal of this carbohydrate moiety (up to 91%) was achieved by incubation with trifluoromethane sulfonic acid. 4. The deglycosylated CSF-1 (DG-CSF-1) possesses an apparent Mr 38,000 compared to native CSF-1 with an initial Mr 57,000 (Goa et al., 1988). 5. The features of the interaction of radio-iodinated [125I]CSF-1 with single cell suspensions from various human tissues (bone marrow, spleen, blood, peritoneal cavity, alveolar lavage, lymph node and thymus), were studied. 6. The binding activity of peritoneal macrophages was the highest among the cells examined and erythrocytes, thymus and blood granulocytes showed no CSF-1 binding. 7. On incubation with [125I]CSF-1 at 0 degrees C, cellular binding of [125I]CSF-1 reached a stable maximum within 16 hr. This is in contrast to the association behaviour at higher temperature. 8. At 37 degrees C, cellular associated [125I]CSF-1 levels reached, within 90 min, an unstable maximum which was up to 10 times less than that occurring under the same conditions at 0 degree C. From the Scatchard plot analysis, we obtained the affinity constant and the number of receptor(s). 9. The binding site is sensitive to trypsin. 10. The receptor alone, (labelled by cross-linking to [125I]CSF-1 with di-succinylimidyl-suberate), is a polypeptide with an approx. Mr 110,000. 11. Our results showed that the receptor of CSF-1 is a tyrosin-kinase.     

Induction of IL-6 release from human T cells by PAR-1 and PAR-2 agonists

Proteinase-activated receptors (PAR) have been recognized as playing an important role in inflammation and immune response. However, little is known of the expression and function of PAR on human T cells. In this study, the expression of PAR on highly purified human T cells was determined and the secretion of IL-6 from cultured T cells in response to serine proteinases and agonist peptides of PAR was examined. The results showed that T cells express PAR-1, PAR-2 and PAR-3 proteins and genes. Thrombin, trypsin and tryptase, but not elastase, were able to stimulate concentration-dependent secretion of IL-6 from T cells following a 16 h incubation period. The specific inhibitors of thrombin, trypsin and tryptase inhibited the actions of these proteinases on T cells, indicating that the enzymatic activity is essential for their actions. Agonist peptides of PAR SFLLR-NH2, TFLLRN-NH2 and SLIGKV-NH2, but not TFRGAP-NH2, GYPGQV-NH2 and AYPGKF-NH2, are also capable of inducing IL-6 release from T cells. In conclusion, induction of IL-6 secretion from T cells by thrombin, trypsin and tryptase is probably through the activation of PAR, suggesting that serine proteinases are involved in the regulation of immune response of the body.     

Spectroscopic and biochemical analysis of regions of the cell wall of the unicellular 'mannan weed', Acetabularia acetabulum

Although the Dasycladalean alga Acetabularia acetabulum has long been known to contain mannan-rich walls, it is not known to what extent wall composition varies as a function of the elaborate cellular differentiation of this cell, nor has it been determined what other polysaccharides accompany the mannans. Cell walls were prepared from rhizoids, stalks, hairs, hair scars, apical septa, gametophores and gametangia, subjected to nuclear magnetic resonance and Fourier transform infrared spectroscopy, and analyzed for monosaccharide composition and linkage, although material limitations prevented some cell regions from being analyzed by some of the methods. In diplophase, walls contain a para-crystalline mannan, with other polysaccharides accounting for 10-20% of the wall mass; in haplophase, gametangia have a cellulosic wall, with mannans and other polymers representing about a quarter of the mass. In the walls of the diplophase, the mannan appears less crystalline than typical of cellulose. The walls of both diploid and haploid phases contain little if any xyloglucan or pectic polysaccharides, but appear to contain small amounts of a homorhamnan, galactomannans and glucogalactomannans, and branched xylans. These ancillary polysaccharides are approximately as abundant in the cellulose-rich gametangia as in the mannan-rich diplophase. In the diplophase, different regions of the cell differ modestly but reproducibly in the composition of the cell wall. These results suggest unique cell wall architecture for the mannan-rich cell walls of the Dasycladales.