Preparation and biomedical application of a non-polymer coated superparamagnetic nanoparticle

We report the preparation of a non-polymer coated superparamagnetic nanoparticle that is stable and biocompatible both in vitro and in vivo. The non-polymer, betaine, is a natural methylating agent in mammalian liver with active surface property. Upon systemic administration, the nanoparticle has preferential biodistribution in mammalian liver and exhibits good reduction of relaxivity time and negative enhancement for the detection of hepatoma nodules in rats using MRI. Our data demonstrate that the non-polymer coated superparamagnetic nanoparticle should have potential applications in biomedicine.     

Identification and functional analysis of LsMNPV anti-apoptosis genes

Three anti-apoptosis genes, Ls-iap2, iap3 and p49 were found in Leucania separata multiple nuclear polyhedrovirus. Amino acid sequence homology of Ls-IAP2 and Ls-IAP3 with Op-IAP2 and Op-IAP3 from Orgyia pseddotsugata MNPV were 20% and 42%, while that of Ls-P49 is 28% with Sl-P49 from Spodoptera littorolis MNPV. Ls-IAP2 contains one baculoviral IAP repeat (BIR) domain followed by a RING domain, while Ls-IAP3 contains two BIRs and a RING. Ls-P49 contains a reactive site loop, predicted cleavage site (KKLD(74) downward arrow G) that is different from Sl-P49 (TVID(94) downward arrow G). Expressed Ls-iap3 or Ls-p49 under presence of actinomycin D in SF9 cells, DNA ladder assay revealed that Ls- IAP3 or Ls-P49 could block the apoptosis of SF9 cells induced by actinomycin D. Replication of p35 deficient-mutant Autographa californica MNPV in SF9 cells was also rescued when Ls-iap3 or Ls-p49 was expressed transiently. No anti-apoptotic activity was observed for Ls-IAP2. The results showed that both of Ls-IAP3 and Ls-P49 were functional apoptotic suppressors in SF9 cells.     

Function and oligomerization study of the leucine zipper-like domain in P13 from Leucania separata multiple nuclear polyhedrosis virus

The p13 gene is uniquely present in Group II nucleopolyhedroviruses (NPVs) and some granuloviruses, but not in Group I NPVs. p13 gene was first described by our laboratory in Leucania separatamultiple nuclear polyhedrosis virus (Ls-p13) in 1995. However, the functions of Ls-P13 and of its homologues are unknown. When Ls-p13 was inserted into Autographa californica nucleopolyhedrovirus, a Group I NPV, polyhedra yield was inhibited. However, this inhibition was prevented when the leucine zipper-like domain of Ls-p13 was mutated. To determine the cause of this marked difference between Ls-P13 and leucine zipper mutated Ls-P13 (Ls-P13mL), oligomerization and secondary structure analyses were performed. High performance liquid chromatography and yeast two-hybrid assays indicated that neither Ls-P13 nor Ls-P13mL could form oligomers. Informatics and circular dichroism spectropolarimetry results further indicated marked secondary structural differences between Ls-P13 and Ls-P13mL. The LZLD of Ls-P13 has two extended heptad repeat units which form a hydrophobic surface, but it is short of a third hydrophobic heptad repeat unit for oligomerization. However, the mutated LZLD of Ls-P13mL lacks the above hydrophobic surface, and its secondary structure is markedly different. This difference in its secondary structure may explain why Ls-P13mL is unable to inhibit polyhedra yield.     

Deferoxamine synergistically enhances iron-mediated AP-1 activation: a showcase of the interplay between extracellular-signal-regulated kinase and tyrosine phosphatase

Deferoxamine (DFO) is a drug widely used for iron overload treatment to reduce body iron burden. In the present study, it was shown in mouse epidermal JB6 cells that all iron compounds transiently induced extracellular signal-regulated kinases (ERK) phosphorylation, whereas DFO further enhanced ERK phosphorylation over long periods. The ERK phosphorylation by DFO treatment appears to be due to the inhibition of MAPK phosphatases (MKP) by DFO. The combined effects of iron-initiated MAPK activation and DFO-mediated MKP inhibition resulted in a synergistic enhancement on AP-1 activities. The results indicate that the interplay between MAPK and MKP is important in regulating the extent of AP-1 activation. It is known that administration of DFO in iron overload patients often results in allergic responses at the injection sites. The results suggest that this synergistic AP-1 activation might play a role in DFO-induced skin immune responses of iron overload patients.     

Role of Drosophila gene dunc-115 in nervous system

Axonal guidance signals are transduced through growth cone surface receptors to the interior leading to changes of actin dynamics and actin binding proteins, which are critical in determining the outcome of actin cytoskeleton reorganization. We report here the characterization of the Drosophila actin binding protein abLIM/Unc-115 homolog Dunc-115 and its role in the nervous system. Three Dunc-115 isoforms are identified as Dunc-115L, M and S, respectively. While Dunc-115L is a canonical homolog of Unc-115 with four LIM domains and one villin headpiece domain, Dunc-115M and S are novel isoforms without counterparts in other species. Our molecular modeling shows Dunc-115L is likely to bind to actin. Mutant analysis reveals that Dunc-115 is involved in axonal projection in both the visual and central nervous system.     

Intermedin/adrenomedullin 2及其受体在慢性低氧性肺动脉高压大鼠右心室的表达变化

本研究探讨了新发现的小分子生物活性肽intermedin／adrenomedullin 2（IMD／ADM2）及其受体在慢性低氧性肺动脉高压大鼠右心室中的变化和可能作用。用放射免疫分析法测定正常对照组和常压低氧4周组Sprague-Dawley大鼠血浆、右心室匀浆IMD／ADM2和肾上腺髓质素（adrenomednllin,ADM）蛋白水平;逆转录-多聚酶链反应法测定右心室IMD／ADM2、ADM及受体：降钙素受体样受体（calcitonin receptor-like receptor,CRLR）、受体活性修饰蛋白1,2,3（receptor activity modifying protein 1,2,3,RAMP1,RAMP2,RAMP3）mRNA表达。结果显示：低氧组平均肺动脉压、右心室与左心室加室间隔重量比[RV／（LV＋S）]显著高于对照组（均P〈0．01）;低氧组血浆和右心室组织匀浆ADM水平比对照组分别高1．26倍和1．68倍（P〈0．01）,IMD／ADM2水平则较对照组分别高0．90倍和1．19倍（P〈0．01）;与对照组相比,低氧组右心室IMD／ADM2、ADM mRNA表达均上调（P〈0．01）,RAMP2 mRNA表达增强（P〈0．05）,而两组间CRLR、RAMP1、RAMP3 mRNA的表达水平无显著性差异。结果表明,慢性低氧性肺动脉高压大鼠IMD／ADM2表达水平升高。     

植物生理与分子生物学

主要从病毒诱导的基因沉默体系中植物与病毒的相互作用、VIGS涉及的信号分子和移动方式以及靶基因的沉默和病毒载体的复制关系介绍和分析植物病毒诱导的基因沉默效应的分子机制,并进一步分析此种体系在植物基因功能研究中应用的研究进展。     

刺枝野丁香和穗花野丁香(茜草科)名称之合格发表

刺枝野丁香Leptodermis pilosa Diels var．acanthoclada Lo和穗花野丁香L．pilosa Diels vat．spicatiformis Lo发表时没指明模式,是不合格发表的名称。现通过指定模式,将它们的名称作合格发表。还对此2新变种及其近缘类群提供了分类检索表和地理分布图。     

关于木本石松植物鳞皮木属的正确名称

讨论了木本石松植物鳞皮木属Lepidophloios Stemberg的正确名称。基于Stemberg 1825年的原始描述和相关文献以及模式标本,Lepidophloios实际上是一个晚出的拼写变体,它的原始拼写为Lepidopfloyos。根据《国际植物命名法规》（维也纳法规规则60．1和61．1）,Lepidofloys Stemberg应该是鳞皮木属的正确名称。作者给出了鳞皮木属模式标本的图片和描述。