Overexpression of Kdr in adult endocardium induces endocardial neovascularization and improves heart function after myocardial infarction

Dear Editor, Coronary artery disease is a leading cause of mortality and morbidity worldwide.Blockade of effective blood flow to heart muscles results in cardi...     

Genetic characteristics of 2009 pandemic H1N1 influenza a viruses isolated from Mainland China

A total of 100 HIN1 flu real-time-PCR positive throat swabs collected from fever patients in Zhejiang,Hubei and Guangdong between June and November 2009,were provided by local CDC laboratories.After MDCK cell culture,57 Influenza A Pandemic (H1N1) viruses were isolated and submitted for whole genome sequencing.A total of 39 HA sequences,52 NA sequences,36 PB2 sequences,31 PB1 sequences,40 PA sequences,48 NP sequences,51 MP sequences and 36 NS sequences were obtained,including 20 whole genome sequences.Sequence comparison revealed they shared a high degree of homology (96％～99％) with known epidemic strains (A/Califomia/04/2009(H1N1).Phylogenetic analysis showed that although the sequences were highly conserved,they clustered into a small number of groups with only a few distinct strains.Site analysis revealed three substitutions at loop 220 (221-228) of the HA receptor binding site in the 39 HA sequences:A/Hubei/86/2009 PKVRDQEG→PKVRDQEA,A/Zhejiang/08/2009 PKVRDQEG→PKVRDQER,A/Hubei/75/2009PKVRDQEG→PKVRDQGG,the A/Hubei/75/2009 was isolated from an acute case,while the other two were from patients with mild symptoms.Other key sites such as 119,274,292 and 294 amino acids of NA protein,627 of PB2 protein were conserved.Meanwhile,all the M2 protein sequences possessed the Ser32Asn mutation,suggesting that these viruses were resistant to adamantanes.Comparison of these sequences with other H1N1 viruses collected from the NCBI database provides insight into H1N1 transmission and circulation patterns.     

Preparation and characterization of fusion protein truncated Pseudomonas Exotoxin A (PE38KDEL) in Escherichia coli

Pseudomonas Exotoxin A (PE) and truncated PE have been used to prepare immunotoxin with monoclonal antibodies. Truncated Pseudomonas Exotoxin A (PE38KDEL) was expressed with the pET-32a(+) vector in Escherichia coli under control of a T7 promoter. The recombinant protein was purified by His-Ni(2+) metal affinity chromatography and gel filtration. The biological activity of PE38KDEL was evaluated by the inhibition assay of protein synthesis in rabbit reticulocyte lysate system, and the cytotoxicity was tested in Hut 102 and hepatocellular cell lines by the MTS assay. PE38KDEL can significantly inhibit luciferase synthesis in cell-free protein synthesis assay and was slightly cytotoxic in the Hut 102 and hepatocellular cell lines. The results suggest that PE38KDEL would be useful for the preparation of more potent immunotoxins.     

Microbial nitrogen and phosphorus co-limitation across permafrost region

The status of plant and microbial nutrient limitation have profound impacts on ecosystem carbon cycle in permafrost areas, which store large amounts of carbon and experience pronounced climatic warming. Despite the long-term standing paradigm assumes that cold ecosystems primarily have nitrogen deficiency, large-scale empirical tests of microbial nutrient limitation are lacking. Here we assessed the potential microbial nutrient limitation across the Tibetan alpine permafrost region, using the combination of enzymatic and elemental stoichiometry, genes abundance and fertilization method. In contrast with the traditional view, the four independent approaches congruently detected widespread microbial nitrogen and phosphorus co-limitation in both the surface soil and deep permafrost deposits, with stronger limitation in the topsoil. Further analysis revealed that soil resources stoichiometry and microbial community composition were the two best predictors of the magnitude of microbial nutrient limitation. High ratio of available soil carbon to nutrient and low fungal/bacterial ratio corresponded to strong microbial nutrient limitation. These findings suggest that warming-induced enhancement in soil nutrient availability could stimulate microbial activity, and probably amplify soil carbon losses from permafrost areas.     

Phosphorene as Cathode Material for High‐Voltage,Anti‐Self‐Discharge Zinc Ion Hybrid Capacitors

Output voltage and self‐discharge rate are two important performance indices for supercapacitors, which have long been overlooked, though these play a very significant role in their practical application. Here, a zinc anode is used to construct a zinc ion hybrid capacitor. Expanded operating voltage of the hybrid capacitor is obtained with novel electrolytes. In addition, significantly improved anti‐self‐discharge ability is achieved. The phosphorene‐based zinc ion capacitor exploiting a “water in salt” electrolyte with a working potential can reach 2.2 V, delivering 214.3 F g^?1 after 5000 cycles. The operating voltage is further extended to 2.5 V through the use of an organic solvent as the electrolyte; the solvent is prepared by adding 0.2 m ZnCl₂ into the tetraethylammonium tetrafluoroborate in propylene carbonate (Et₄NBF₄/PC) solvent, and it exhibits 105.9 F g^?1 even after 9500 cycles. More importantly, the phosphorene‐based capacitors possess excellent anti‐self‐discharge performance. The capacitors retain 76.16% of capacitance after resting for 300 h. The practical application of the zinc ion capacitor is demonstrated through a flexible paper‐based printed microcapacitor. It is believed that the developed zinc ion capacitor can effectively resolve the severe self‐discharge problem of supercapacitors. Moreover, high‐voltage zinc ion capacitors provide more opportunities for the application of supercapacitors.     

Callus induction and shoot organogenesis from anther cultures of Curcuma attenuata Wall

Curcuma attenuata is a highly valued ornamental. This study provides the first report on C. attenuata shoot organogenesis and plant regeneration. Immature anthers derived from 5 to 7?cm long inflorescences were isolated and cultured on different variations of Murashige and Skoog (MS) media to induce callus and then shoot organogenesis. When the 2-mm long anthers in which microspores were at the uninucleate developmental stage were cultured in the dark on MS medium containing 13.6???M 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.3???M kinetin (KT) for 15?days and then transferred to 40???mol?m^?2?s^?1 fluorescent light for 30?days, the percentage callus induction reached 33.3?%. After callus was transferred to various differentiation media and cultured in the light, 33.1?% of all callus cultures could differentiate into adventitious shoots on MS medium supplemented with 22.0???M 6-benzyladenine (BA), 0.53???M ??-naphthaleneacetic acid (NAA) and 1.4???M thidiazuron (TDZ) after culturing for 60?days. Over 95?% of plantlets survived after transplanting plantlets into trays with a mixture of sand and perlite (2: 1) for 20?days. Chromosome number, determined from the root tips of young plantlets, indicated that all plantlets were diploid (2n?=?84).     

Variation in the δ<Superscript>13</Superscript>C of Two Mangrove Plants is Correlated with Stomatal Response to Salinity

To better understand the relationship between salinity and the carbon stable isotope composition (expressed as δ¹³C) of mangrove plants and to test whether the patterns of variation in δ¹³C of mangrove plants differ from those of nonhalophytes as response to salinity, the effect of salinity on leaf δ¹³C in two dominant mangrove species, Aegiceras corniculatum and Kandelia candel, was studied. Furthermore, to determine whether the variation in δ¹³C of mangrove species is adjusted by stomatal conductance, K. candel was selected as an example, and leaf gas-exchange characteristics of the seedlings were measured. It was observed that both mangrove species had a lower leaf δ¹³C under their optimum salinity (1.50% for Ae. corniculatum and 2.00% for K. candel). This variation in δ¹³C of mangrove plants was attributable largely to stomatal adjustment as for nonhalophytes in which a strong correlation between δ¹³C and relevant photosynthetic properties is observed. This result suggests that the different response pattern in δ¹³C was a consequence of the variation in stomata in relation to the different tolerance to salinity. The optimum salinity inferred by leaf δ¹³C provides a feasible method for comparing salt tolerance between mangrove plants belonging to different species, which is useful for mangrove restoration.     

Dynamic reprogramming of histone acetylation and methylation in the first cell cycle of cloned mouse embryos

Epigenetic reprogramming is thought to play an important role in the development of cloned embryos reconstructed by somatic cell nuclear transfer (SCNT). In the present study, dynamic reprogramming of histone acetylation and methylation modifications was investigated in the first cell cycle of cloned embryos. Our results demonstrated that part of somatic inherited lysine acetylation on core histones (H3K9, H3K14, H4K16) could be quickly deacetylated following SCNT, and reacetylation occurred following activation treatment. However, acetylation marks of the other lysine residues on core histones (H4K8, H4K12) persisted in the genome of cloned embryos with only mild deacetylation occurring in the process of SCNT and activation treatment. The somatic cloned embryos established histone acetylation modifications resembling those in normal embryos produced by intracytoplasmic sperm injection through these two different programs. Moreover, treatment of cloned embryos with a histone deacetylase inhibitor, Trichostatin A (TSA), improved the histone acetylation in a manner similar to that in normal embryos, and the improved histone acetylation in cloned embryos treated with TSA might contribute to improved development of TSA-treated clones. In contrast to the asymmetric histone H3K9 tri- and dimethylation present in the parental genomes of fertilized embryos, the tri- and dimethylations of H3K9 were gradually demethylated in the cloned embryos, and this histone H3K9 demethylation may be crucial for gene activation of cloned embryos. Together, our results indicate that dynamic reprogramming of histone acetylation and methylation modifications in cloned embryos is developmentally regulated.     

C3植物稳定碳同位素组成与盐分的关系

植物在盐生环境中δ13C值的改变可能包含两个成分:一个是盐分对CO2的扩散、传递或光合速率的影响而引起的δ13C值的改变;另一个是光合途径的转换引起的δ13C值的变化,δ13C值的大小与诱导发生CAM或C4代谢的程度有关.植物组织的δ13C值随盐度的变化趋势除了与植物本身固有的耐盐性有关以外,盐度和胁迫时间是影响植物δ13C的重要因素.根据盐生条件下同位素分馏特点可知,盐生植物与非盐生植物的δ13C随盐度的变化趋势有所不同.对非盐生植物而言,在低盐度和短期的盐处理下,随盐度的增加和胁迫时间的延长植物的δ13C值增大,这个阶段限制光合作用的主要因素是气孔导度;但是如果盐度过低,δ13C变化很小,则难以表现出应有的相关性;随着胁迫的加强,当限制光合作用的非气孔因素成为主导因素时,由于光合作用受到强烈抑制(光合结构遭到破坏),δ13C将随之降低.对盐生植物而言,其δ13C与最适盐度有关.最适盐度下,植物的δ13C低于其它盐度条件下的δ13C值.盐生条件下,有些C3植物可能发生光合途径的转换,无论诱导发生的是C4代谢还是CAM代谢,δ13C值均趋于增大.但是,一般情况下,盐处理诱导的光合途径的改变对植物组织整体的δ13C的影响很小.在密闭环境中或郁闭林地,植物和土壤呼吸释放的CO2再次参与光合作用,也会改变植物的δ13C值.为了更加全面地考察植物δ13C与盐度的关系,需要设置较大的盐度范围和进行长期的胁迫处理,才能够获得相对充分的数据,才有利于全面分析植物δ13C值与耐盐性的关系.     

Crumbs proteins stabilize the cone mosaics of photoreceptors and improve vision in zebrafish

Although the unique organization of vertebrate cone mosaics was first described long ago,both their underlying molecular basis and physiological significance are largely unknown.Here,we demonstrate that Crumbs proteins,the key regulators of epithelial apical polarity,establish the planar cellular polarity of photoreceptors in zebrafish.Via heterophilic Crb2a-Crb2b interactions,the apicobasal polarity protein Crb2b restricts the asymmetric planar distribution of Crb2a in photoreceptors.The planar polarized Crumbs proteins thus balance intercellular adhesions and tension between photoreceptors,thereby stabilizing the geometric organization of cone mosaics.Notably,loss of Crb2b in zebrafish induces a nearsightedness-like phenotype in zebrafish accompanied by an elongated eye axis and impairs zebrafish visual perception for predation.These data reveal a detailed mechanism for cone mosaic homeostasis via previously undiscovered apical-planar polarity coordination and propose a pathogenic mechanism for nearsightedness.