Draft Genome Sequence of Fusobacterium nucleatum subsp. fusiforme ATCC 51190T

Fusobacterium nucleatum, one of the major causative bacteria of periodontitis, is classified into five subspecies (nucleatum, polymorphum, vincentii, animalis, and fusiforme) on the basis of the several phenotypic characteristics and DNA homology. This is the first report of the draft genome sequence of F. nucleatum subsp. fusiforme ATCC 51190(T).     

Fluorescence imaging in vivo: recent advances

In vivo fluorescence imaging uses a sensitive camera to detect fluorescence emission from fluorophores in whole-body living small animals. To overcome the photon attenuation in living tissue, fluorophores with long emission at the near-infrared (NIR) region are generally preferred, including widely used small indocarbocyanine dyes. The list of NIR probes continues to grow with the recent addition of fluorescent organic, inorganic and biological nanoparticles. Recent advances in imaging strategies and reporter techniques for in vivo fluorescence imaging include novel approaches to improve the specificity and affinity of the probes and to modulate and amplify the signal at target sites for enhanced sensitivity. Further emerging developments are aiming to achieve high-resolution, multimodality and lifetime-based in vivo fluorescence imaging.     

PEGylation of lysine residues improves the proteolytic stability of fibronectin while retaining biological activity

Excessive proteolysis of fibronectin (FN) impairs tissue repair in chronic wounds. Since FN is essential in wound healing, our goal is to improve its proteolytic stability and at the same time preserve its biological activity. We have previously shown that reduced FN conjugated with polyethylene glycol (PEG) at cysteine residues is more proteolytically stable than native FN. Cysteine‐PEGylated FN supported cell adhesion and migration to the same extent as native FN. However, unlike native FN, cysteine‐PEGylated FN was not assembled into an extracellular matrix (ECM) when immobilized. Here, we present an alternative approach in which FN is preferentially PEGylated at lysine residues using different molecular weight PEGs. We show that lysine PEGylation does not perturb FN secondary structure. PEG molecular weight, from 2 to 10 kDa, positively correlates with FN–PEG proteolytic stability. Cell adhesion, cell spreading, and gelatin binding decrease with increasing molecular weight of PEG. The 2‐kDa FN–PEG conjugate shows comparable cell adhesion to native FN and binds gelatin. Moreover, immobilized FN–PEG is assembled into ECM fibrils. In summary, lysine PEGylation of FN can be used to stabilize FN against proteolytic degradation with minimal perturbation to FN structure and retained biological activity.     

Distinct Biology of Kaposi’s Sarcoma-Associated Herpesvirus from Primary Lesions and Body Cavity Lymphomas

The DNA sequence for Kaposi’s sarcoma-associated herpesvirus was originally detected in Kaposi’s sarcoma biopsy specimens. Since its discovery, it has been possible to detect virus in cell lines established from AIDS-associated body cavity-based B-cell lymphoma and to propagate virus from primary Kaposi’s sarcoma lesions in a human renal embryonic cell line, 293. In this study, we analyzed the infectivity of Kaposi’s sarcoma-associated herpesvirus produced from these two sources. Viral isolates from cultured cutaneous primary KS cells was transmitted to an Epstein-Barr virus-negative Burkitt’s B-lymphoma cell line, Louckes, and compared to virus induced from a body cavity-based B-cell lymphoma cell line. While propagation of body cavity-based B-cell lymphoma-derived virus was not observed in 293 cell cultures, infection with viral isolates obtained from primary Kaposi’s sarcoma lesions induced injury in 293 cells typical of herpesvirus infection and was associated with apoptotic cell death. Interestingly, transient overexpression of the Kaposi’s sarcoma-associated herpesvirus v-Bcl-2 homolog delayed the process of apoptosis and prolonged the survival of infected 293 cells. In contrast, the broad-spectrum caspase inhibitors Z-VAD-fmk and Z-DEVD-fmk failed to protect infected cell cultures, suggesting that Kaposi’s sarcoma-associated herpesvirus-induced apoptosis occurs through a Bcl-2-dependent pathway. Kaposi’s sarcoma-associated herpesvirus isolates from primary Kaposi’s sarcoma lesions and body cavity-based lymphomas therefore may differ and are likely to have distinct contributions to the pathophysiology of Kaposi’s sarcoma.     

The effect of different platelet-rich plasma concentrations on proliferation and differentiation of human periodontal ligament cells in vitro

OBJECTIVES: The use of platelets and platelet products has become increasingly popular clinically as a means of accelerating endosseous wound healing. It is likely that growth factors released by activated platelets at the site of injury play a role in periodontal regeneration by regulating cellular activity. The purpose of this study was to evaluate the biological effects of platelet-rich plasma (PRP) on human periodontal ligament cells (hPDLCs) in vitro. MATERIALS AND METHODS: Primary cultures of hPDLCs were obtained from healthy premolars. PRP was isolated by two-step centrifugation. Two main growth factors present in the thrombin-activated PRP (platelet-derived growth factor [PDGF-AB] and transforming growth factor-beta1 [TGF-beta1]) were evaluated using ELISA assay. Activated PRP or the combination of recombined human TGF-beta1 (rhTGF-beta1) and PDGF-AB (rhPDGF-AB) were added to hPDLCs in different concentrations to assess cell proliferation and osteogenic differentiation. RESULTS: PRP contained high levels of TGF-beta1 and PDGF-AB. Cell attachment, proliferation and ALP activity were enhanced by addition of PRP or rhTGF-beta1 and rhPDGF-AB combination to the cell cultures, while the stimulatory potency of PRP was much greater than the latter. These stimulatory effects presented in a dose-dependant manner, it seemed that PRP with 50~100 ng/ml TGF-beta1 was an ideal concentration. CONCLUSIONS: PRP can enhance hPDLC adhesion, proliferation and induce the differentiation of hPDLC into mineralized tissue formation cell; thereby contribute to the main processes of periodontal tissue regeneration. For economical and biological reasons, PRP has more clinical beneficial than analogous growth factors.     

The plant glycosyltransferase clone collection for functional genomics

The glycosyltransferases (GTs) are an important and functionally diverse family of enzymes involved in glycan and glycoside biosynthesis. Plants have evolved large families of GTs which undertake the array of glycosylation reactions that occur during plant development and growth. Based on the Carbohydrate‐Active enZymes (CAZy) database, the genome of the reference plant Arabidopsis thaliana codes for over 450 GTs, while the rice genome (Oryza sativa) contains over 600 members. Collectively, GTs from these reference plants can be classified into over 40 distinct GT families. Although these enzymes are involved in many important plant specific processes such as cell‐wall and secondary metabolite biosynthesis, few have been functionally characterized. We have sought to develop a plant GTs clone resource that will enable functional genomic approaches to be undertaken by the plant research community. In total, 403 (88%) of CAZy defined Arabidopsis GTs have been cloned, while 96 (15%) of the GTs coded by rice have been cloned. The collection resulted in the update of a number of Arabidopsis GT gene models. The clones represent full‐length coding sequences without termination codons and are Gateway^® compatible. To demonstrate the utility of this JBEI GT Collection, a set of efficient particle bombardment plasmids (pBullet) was also constructed with markers for the endomembrane. The utility of the pBullet collection was demonstrated by localizing all members of the Arabidopsis GT14 family to the Golgi apparatus or the endoplasmic reticulum (ER). Updates to these resources are available at the JBEI GT Collection website http://www.addgene.org/ .     

苏云金芽孢杆菌S1478-1分离株的特性鉴定及cry1Ac同源基因克隆

本研究对从海南岛尖峰岭热带雨林自然保护区的土壤样品中分离出的Bt菌株S1478-1进行了特性鉴定,研究表明S1478-1分离株菌落形态和生长特征和Bt参照菌株HD73极其相似.16S rDNA序列分析表明,S1478-1分离株与其它B.thuringiensis、B.cereus和B.anthracis的16S rDNA序列相似性达到99%.分离株能产菱形伴胞晶体,SDS-PAGE蛋白电泳分析表明,菌株在生长后期,形成芽孢同时分泌130 kD大小的晶体蛋白.生物测定表明S1478-1分离株对小菜蛾具有很高的毒杀活性,LC50卯值高达5.159 ×108cfu/mL.初步显示S1478-1分离株可作为防治鳞翅目害虫的生物农药菌株.利用PCR-RFLP方法鉴定S1478-1分离株含有cry1Ac同源基因,以PCR粘性端克隆方法扩增全长基因,序列测定表明该基因ORF为3 537bp,编码1178个氨基酸,推定的编码蛋白分子量为133.3 kD,与其它cry1Ac基因序列最高达到99%同源,因此,该基因可作为杀虫工程菌及培育转基因抗虫作物的候选基因.