人胎盘滋养层细胞培养与体外hCG释放的研究

本研究的目的是了解细胞滋养层细胞和合胞体滋养层细胞体外分化和生物学特性。方法:采用酶消化和Percoll密度梯度离心法,对人足月胎盘细胞滋养层细胞进行分离、纯化和体外培养。采用放射免疫法(RIA)检测细胞培养上清液hCG含量的变化。结果:经分离和纯化的细胞滋养层细胞在体外培养中生长良好,通过细胞分裂和融合形成合胞体滋养层细胞,随着合胞体滋养层细胞的生长,细胞培养上清液中hCG含量显著升高。我们认为从胎盘中分离和纯化的细胞滋养层细胞在体外培养中可分化和融合形成合胞体滋养层细胞,体外hCG含量的增加与合胞体滋养层细胞生长有关。     

OsGRF4 controls grain shape,panicle length and seed shattering in rice

Traits such as grain shape, panicle length and seed shattering, play important roles in grain yield and harvest. In this study, the cloning and functional analysis of PANICLE TRAITS 2 (PT2), a novel gene from the Indica rice Chuandali (CDL), is reported. PT2 is synonymous with Growth‐Regulating Factor 4 (OsGRF4), which encodes a growth‐regulating factor that positively regulates grain shape and panicle length and negatively regulates seed shattering. Higher expression of OsGRF4 is correlated with larger grain, longer panicle and lower seed shattering. A unique OsGRF4 mutation, which occurs at the OsmiRNA396 target site of OsGRF4, seems to be associated with high levels of OsGRF4 expression, and results in phenotypic difference. Further research showed that OsGRF4 regulated two cytokinin dehydrogenase precursor genes (CKX5 and CKX1) resulting in increased cytokinin levels, which might affect the panicle traits. High storage capacity and moderate seed shattering of OsGRF4 may be useful in high‐yield breeding and mechanized harvesting of rice. Our findings provide additional insight into the molecular basis of panicle growth.     

松口蘑菌丝体的分离和RAPD-PCR分析

针对松口蘑 [Tricholomamatsutake(S .ItoetImai)Sing .]菌丝体分离培养困难和各种相关分离物目前难以用出菇试验鉴定的现实 ,采用 8种培养基配方 ,对 9个不同来源的松口蘑子实体的不同部位及菌根、菌土进行组织分离 ,计接种试管 81 0多支 ,结果从菌褶部位获得 94支慢生型的菌丝体分离菌株 ,从菌柄部位仅获得 1支快生型的菌丝体分离菌株。以马铃薯葡萄糖土壤滤液培养基 (PDAS)、马铃薯葡萄糖麦麸滤液培养基 (PDAW )、BM培养基、马铃薯葡萄糖琼脂培养基 (PDA)对菌褶进行组织分离 ,获慢生型菌丝体的成功率依次为 74.4%、35.5%、156%和 8.9%。以各分离菌株的来源松口蘑子实体和中日两国松口蘑研究者提供的分离菌株作为DNA参照样品 ,对从供试子实体、菌根、菌土进行组织分离获得的各种相关纯培养物进行亲菌鉴定。采用筛选的 1 7个随机引物介导 2 5个供试松口蘑子实体及其分离菌体的RAPD(RandomAmplifiedPolymorphicDNA) PCR反应 ,全部获得了清晰而稳定的DNA指纹图谱 ,结果一致表明 :每个松口蘑子实体的菌盖 (含菌褶…     

EFFECTS OF INCREASED TEMPERATURE AND CO2 ON PHOTOSYNTHESIS,GROWTH, AND ELEMENTAL RATIOS IN MARINE SYNECHOCOCCUS AND PROCHLOROCOCCUS (CYANOBACTERIA)1

Little is known about the combined impacts of future CO₂ and temperature increases on the growth and physiology of marine picocyanobacteria. We incubated Synechococcus and Prochlorococcus under present‐day (380 ppm) or predicted year‐2100 CO₂ levels (750 ppm), and under normal versus elevated temperatures (+4°C) in semicontinuous cultures. Increased temperature stimulated the cell division rates of Synechococcus but not Prochlorococcus. Doubled CO₂ combined with elevated temperature increased maximum chl a–normalized photosynthetic rates of Synechococcus four times relative to controls. Temperature also altered other photosynthetic parameters (α, Φ_max, E_k, and ) in Synechococcus, but these changes were not observed for Prochlorococcus. Both increased CO₂ and temperature raised the phycobilin and chl a content of Synechococcus, while only elevated temperature increased divinyl chl a in Prochlorococcus. Cellular carbon (C) and nitrogen (N) quotas, but not phosphorus (P) quotas, increased with elevated CO₂ in Synechococcus, leading to ～20% higher C:P and N:P ratios. In contrast, Prochlorococcus elemental composition remained unaffected by CO₂, but cell volume and elemental quotas doubled with increasing temperature while maintaining constant stoichiometry. Synechococcus showed a much greater response to CO₂ and temperature increases for most parameters measured, compared with Prochlorococcus. Our results suggest that global change could influence the dominance of Synechococcus and Prochlorococcus ecotypes, with likely effects on oligotrophic food‐web structure. However, individual picocyanobacteria strains may respond quite differently to future CO₂ and temperature increases, and caution is needed when generalizing their responses to global change in the ocean.     

Analysis of variable sites between two complete South China tiger (Panthera tigris amoyensis) mitochondrial genomes

In order to investigate the mitochondrial genome of Panthera tigris amoyensis, two South China tigers (P25 and P27) were analyzed following 15 cymt-specific primer sets. The entire mtDNA sequence was found to be 16,957 bp and 17,001 bp long for P25 and P27 respectively, and this difference in length between P25 and P27 occurred in the number of tandem repeats in the RS-3 segment of the control region. The structural characteristics of complete P. t. amoyensis mitochondrial genomes were also highly similar to those of P. uncia. Additionally, the rate of point mutation was only 0.3% and a total of 59 variable sites between P25 and P27 were found. Out of the 59 variable sites, 6 were located in 6 different tRNA genes, 6 in the 2 rRNA genes, 7 in non-coding regions (one located between tRNA-Asn and tRNA-Tyr and six in the D-loop), and 40 in 10 protein-coding genes. COI held the largest amount of variable sites (9 sites) and Cytb contained the highest variable rate (0.7%) in the complete sequences. Moreover, out of the 40 variable sites located in 10 protein-coding genes, 12 sites were nonsynonymous.     

Effects of macrophage-specific adiponectin expression on lipid metabolism in vivo

Epidemiological studies have associated low circulating levels of the adipokine adiponectin with multiple metabolic disorders, including metabolic syndrome, obesity, insulin resistance, type II diabetes, and cardiovascular disease. Recently, we reported that adiponectin selectively overexpressed in mouse macrophages can improve insulin sensitivity and protect against inflammation and atherosclerosis. To further investigate the role of adiponectin and macrophages on lipid and lipometabolism in vivo, we engineered the expression of adiponectin in mouse macrophages (Ad-TG mice) and examined effects on plasma lipoproteins and on the expression levels of genes involved in lipoprotein metabolism in tissues. Compared with the wild-type (WT) mice, Ad-TG mice exhibited significantly lower levels of plasma total cholesterol (-21%, P < 0.05) due to significantly decreased LDL (-34%, P < 0.05) and VLDL (-32%, P < 0.05) cholesterol concentrations together with a significant increase in HDL cholesterol (+41%, P < 0.05). Further studies investigating potential mechanisms responsible for the change in lipoprotein cholesterol profile revealed that adiponectin-producing macrophages altered expression of key genes in liver tissue, including apoA1, apoB, apoE, the LDL receptor, (P < 0.05), and ATP-binding cassette G1 (P < 0.01). In addition, Ad-TG mice also exhibited higher total and high-molecular-weight adipnection levels in plasma and increased expression of the anti-inflammatory cytokine IL-10 as well as a decrease in the proinflammatory cytokine IL-6 in adipose tissue. These results indicate that macrophages engineered to produce adiponectin can influence in vivo gene expression in adipose tissue in a manner that reduces inflammation and macrophage infiltration and in liver tissue in a manner that alters the circulating lipoprotein profile, resulting in a decrease in VLDL and LDL and an increase in HDL cholesterol. The data support further study addressing the use of genetically manipulated macrophages as a novel therapeutic approach for treatment of cardiometabolic disease.     

Response of rice (Oryza sativa) with root surface iron plaque under aluminium stress

BACKGROUND AND AIMS: Rice (Oryza sativa) is an aquatic plant with a characteristic of forming iron plaque on its root surfaces. It is considered to be the most Al-tolerant species among the cereal crops. The objective of this study was to determine the effects of root surface iron plaque on Al translocation, accumulation and the change of physiological responses under Al stress in rice in the presence of iron plaque. METHODS: The japonica variety rice, Koshihikari, was used in this study and was grown hydroponically in a growth chamber. Iron plaque was induced by exposing the rice roots to 30 mg L(-1) ferrous iron either as Fe(II)-EDTA in nutrient solution (6 d, Method I) or as FeSO(4) in water solution (12 h, Method II). Organic acid in root exudates was retained in the anion-exchange resin and eluted with 2 m HCl, then analysed by high-performance liquid chromatography (HPLC) after proper pre-treatment. Fe and Al in iron plaque were extracted with DCB (dithionite-citrate-bicarbonate) solution. KEY RESULTS AND CONCLUSIONS: Both methods (I and II) could induce the formation of iron plaque on rice root surfaces. The amounts of DCB-extractable Fe and Al on root surfaces were much higher in the presence of iron plaque than in the absence of iron plaque. Al contents in root tips were significantly decreased with iron plaque; translocation of Al from roots to shoots was significantly reduced with iron plaque. Al-induced secretion of citrate was observed and iron plaque could greatly depress this citrate secretion. These results suggested that iron plaque on rice root surfaces can be a sink to sequester Al onto the root surfaces and Fe ions can pre-saturate Al-binding sites in root tips, which protects the rice root tips from suffering Al stress to a certain extent.     

Chaperone-Like Activity of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> Hsp16.3 Does Not Require Its Intact (Native) Structures

Small heat shock proteins (sHsps) were found to exhibit efficient chaperone-like activities under stress conditions although their native structures are severely disturbed. Here, using an alternative approach (site-directed mutagenesis), we obtained two structurally and functionally distinct Mycobacterium tuberculosis Hsp16.3 single-site mutant proteins. The G59W mutant protein (with Gly59 substituted by Trp) is capable of exhibiting efficient chaperone-like activity even under non-stress conditions although its secondary, tertiary, and quaternary structures are very different from that of the wild type protein. By contrast, the G59A mutant protein (with Gly59 substituted by Ala) resembles with the wild type protein in structure and function. These observations suggest that the Gly59 of the Hsp16.3 protein is critical for its folding and assembly. In particular, we propose that the exhibition of chaperone-like activity for Hsp16.3 does not require its intact (native) structures but requires the disturbance of its native structures (i.e., the native structure-disturbed Hsp16.3 retains its chaperone-like activity or even becomes more active). In addition, the behavior of such an active mutant protein (G59W) also strongly supports our previous suggestion that Hsp16.3 exhibits chaperone-like activity via oligomeric dissociation.