Full Conversion of the Hemagglutinin-Neuraminidase Specificity of the Parainfluenza Virus 5 Fusion Protein by Replacement of 21 Amino Acids in Its Head Region with Those of the Simian Virus 41 Fusion Protein

For most parainfluenza viruses, a virus type-specific interaction between the hemagglutinin-neuraminidase (HN) and fusion (F) proteins is a prerequisite for mediating virus-cell fusion and cell-cell fusion. The molecular basis of this functional interaction is still obscure partly because it is unknown which region of the F protein is responsible for the physical interaction with the HN protein. Our previous cell-cell fusion assay using the chimeric F proteins of parainfluenza virus 5 (PIV5) and simian virus 41 (SV41) indicated that replacement of two domains in the head region of the PIV5 F protein with the SV41 F counterparts bestowed on the PIV5 F protein the ability to induce cell-cell fusion on coexpression with the SV41 HN protein while retaining its ability to induce fusion with the PIV5 HN protein. In the study presented here, we furthered the chimeric analysis of the F proteins of PIV5 and SV41, finding that the PIV5 F protein could be converted to an SV41 HN-specific chimeric F protein by replacing five domains in the head region with the SV41 F counterparts. The five SV41 F-protein-derived domains of this chimera were then divided into 16 segments; 9 out of 16 proved to be not involved in determining its specificity for the SV41 HN protein. Finally, mutational analyses of a chimeric F protein, which harbored seven SV41 F-protein-derived segments, revealed that replacement of at most 21 amino acids of the PIV5 F protein with the SV41 F-protein counterparts was enough to convert its HN protein specificity.     

DSP toxin contents inDinophysis fortii and scallops collected at Mutsu Bay,Japan

Cell densities of toxic phytoplankton species responsible for diarrhetic shellfish poisoning (DSP) were monitored at a sampling site in Mutsu Bay, Japan, in 1995.Dinophysis fortii almost completely dominated the toxic phytoplankton community. Okadaic acid (OA) and dinophysistoxin-1 (DTX1) contents in bothD. fortii cells and midgut glands of scallops collected at the same sampling site were determined by HPLC — fluorometry. DTX1 was detected fromD. fortii and scallops. The contents of DTX1 inD. fortii changed markedly during the experimental periods (5–252 pg cell^–1). The highest concentration of DTX1 in the midgut glands of scallops coincided with the period of relatively high cell densities ofD. fortii with the highest content of DTX1 (252 pg cell^–1). The results demonstrate that toxin content in the cells is an important factor affecting the toxicity of shellfish.     

Spirodiketopiperazine-based CCR5 inhibitor which preserves CC-chemokine/CCR5 interactions and exerts potent activity against R5 human immunodeficiency virus type 1 in vitro

We identified a novel spirodiketopiperazine (SDP) derivative, AK602/ONO4128/GW873140, which specifically blocked the binding of macrophage inflammatory protein 1alpha (MIP-1alpha) to CCR5 with a high affinity (K(d) of approximately 3 nM), potently blocked human immunodeficiency virus type 1 (HIV-1) gp120/CCR5 binding and exerted potent activity against a wide spectrum of laboratory and primary R5 HIV-1 isolates, including multidrug-resistant HIV-1 (HIV-1(MDR)) (50% inhibitory concentration values of 0.1 to 0.6 nM) in vitro. AK602 competitively blocked the binding to CCR5 expressed on Chinese hamster ovary cells of two monoclonal antibodies, 45523, directed against multidomain epitopes of CCR5, and 45531, specific against the C-terminal half of the second extracellular loop (ECL2B) of CCR5. AK602, despite its much greater anti-HIV-1 activity than other previously published CCR5 inhibitors, including TAK-779 and SCH-C, preserved RANTES (regulated on activation normal T-cell expressed and secreted) and MIP-1beta binding to CCR5(+) cells and their functions, including CC-chemokine-induced chemotaxis and CCR5 internalization, while TAK-779 and SCH-C fully blocked the CC-chemokine/CCR5 interactions. Pharmacokinetic studies revealed favorable oral bioavailability in rodents. These data warrant further development of AK602 as a potential therapeutic for HIV-1 infection.     

Effect of 3′-end capping of aptamer with various 2′,4′-bridged nucleotides: Enzymatic post-modification toward a practical use of polyclonal aptamers

The capping of the 3′-ends of thrombin binding aptamers (TBAs) with bridged nucleotides increased the nuclease resistances and the stabilities in human serum. The binding abilities of the aptamers were not affected by the capping. The capping could be simply executed via a one step enzymatic process using 2′,4′-bridged nucleoside 5′-triphosphate and terminal deoxynucleotidyl transferase.     

Mouse A9 cells containing single human chromosomes for analysis of genomic imprinting.

To develop an systematic in vitro approach for the study of genomic imprinting, we generated a new library of human/mouse A9 monochromosomal hybrids. We used whole cell fusion and microcell-mediated chromosome transfer to generate A9 hybrids containing a single, intact, bsr-tagged human chromosome derived from primary fibroblasts. A9 hybrids were identified that contained either human chromosome 1, 2, 4, 5, 7, 8, 10, 11, 15, 18, 20, or X. The parental origin of these chromosomes was determined by polymorphic analysis using microsatellite markers, and matched hybrids containing maternal and paternal chromosomes were identified for chromosomes 5, 10, 11 and 15. The imprinted gene KVLQT1 on human chromosome 11p15.5 was expressed exclusively from the maternal chromosome in A9 hybrids, and the parental-origin-specific expression patterns of several other imprinted genes were also maintained. This library of human monochromosomal hybrids is a valuable resource for the mapping and cloning of human genes and is a novel in vitro system for the screening of imprinted genes and for their functional analysis.     

Fine needle aspiration cytology of primary proximal-type epithelioid sarcoma of the perineum: a case report

BACKGROUND: Epithelioid sarcoma is a malignant soft tissue tumor of unknown histogenesis. We describe the cytologic findings in a case of primary proximal-type epithelioid sarcoma of the perineum and results of an immunofluorescence analysis of rhabdoid cells from this tumor. To the best of our knowledge, the 3-color immunofluorescence features of proximal-type epithelioid sarcoma have never before been reported. CASE: An 8-cm-diameter mass with a 2.5-cm ulcer was found in the perineum of a 36-year-old man. After excision of the tumor, histopathologic examination of the resected specimen suggested a diagnosis of proximal-type epithelioid sarcoma. Fine needle aspiration cytology showed numerous rhabdoid cells with globular intracytoplasmic inclusions. A few isolated cells and polygonal cells were also observed in the smears. Three-color immunofluorescence analysis indicated that the intracytoplasmic inclusions in the rhabdoid cells were positive for cytokeratin, vimentin and CD34. The cytoplasmic staining pattern differed between rhabdoid and epithelioid sarcoma cells. CONCLUSION: Immunofluorescent staining of rhabdoid cells from a primary perineal proximal-type epithelioid sarcoma revealed an uneven distribution of cytokeratin in intracytoplasmic inclusions, with the highest concentration at the periphery of the inclusions.     

Algorithms and Complexity Analyses for Control of Singleton Attractors in Boolean Networks

A Boolean network (BN) is a mathematical model of genetic networks. We propose several algorithms for control of singleton attractors in BN. We theoretically estimate the average-case time complexities of the proposed algorithms, and confirm them by computer experiments. The results suggest the importance of gene ordering. Especially, setting internal nodes ahead yields shorter computational time than setting external nodes ahead in various types of algorithms. We also present a heuristic algorithm which does not look for the optimal solution but for the solution whose computational time is shorter than that of the exact algorithms.