[Fluorescence spectra and imaging of Platymonas subcordiformis via LSCM].

Primary investigation of Platymonas subcordiformis was performed with laser scanning microscopic technology. Both autofluorescence spectra and autofluorescence imaging of Platymonas subcordiformis were achieved by one photon excitation of 488 nm Ar+ laser. Autofluorescence images revealed cup-shaped object inside the Platymonas subcordiformis cell, and the corresponding fluorescence peak located at 682 nm was attributed to chloroplast. Moreover, in single channel mode, there existed a round-shaped object in chloroplast center, showing strong fluorescence by 800 nm femtosecond laser excitation. Also, the authors obtained both the individual cup-shaped chloroplast and round-shaped object image and the overlaid images by using dual-channel mode. Meanwhile, six main fluorescence peaks were found. Single photon excitation can be used to obtain autofluorescence image and autofluorescence spectra of Platymonas subcordiformis, while two photon excitation combined with multitrack mode and Lambda mode can be used not only to observe internal structure, but also for the analysis of existence of biological and chemical substances with higher sensitivity than single photon excitation. LSCM technique can be a promising tool for rapid, convenient, real-time and effective investigation in ocean algae.

Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor.

By means of the specific immuno-recognition and ultra-sensitive mass detection, a quartz crystal microbalance (QCM) biosensor for Escherichia coli O157:H7 detection was developed in this work. As a suitable surfactant, 16-mercaptohexadecanoic acid (MHDA) was introduced onto the Au surface of QCM, and then self-assembled with N-hydroxysuccinimide (NHS) raster as a reactive intermediate to provide an active interface for the specific antibody immobilization. The binding of target bacteria with the immobilized antibodies decreased the sensor's resonant frequency, and the frequency shift was correlated to the bacterial concentration. The stepwise assembly of the immunosensor was characterized by means of the electrochemical techniques. Using the immersion-dry-immersion procedure, this QCM biosensor could detect 2.0x10(2) colony forming units (CFU)/ml E. coli O157:H7. In order to reduce the fabrication time, a polyelectrolyte layer-by-layer self-assembly (LBL-SA) method was adopted for fast construction. Finally, the reproducibility of this biosensor was discussed.

[FT-raman spectra study of Platymonas subcordiformis].

FT-Raman spectroscopy was adopted to investigate the Raman spectrum of Platymonas subcordiformis. The result shows that the optimal experiment condition is making sample lose solvent with centrifuge, exciting laser power set at 360 mW and accumulating 70 times. The main peaks of the spectra are 381-432, 552-556, 611-613, 710, 873, 953-964, 1 108-1119, 1457, 1523-1527 and 2986 cm(-1). They belong to protein, insaturation acid and ester, etc, which are the main composition of Platymonas subcordiformis. The precise measurements of algae Raman spectra could be used for developing a new optical taxonomic methodology to distinguish between different algae species, and a rapid, non-destructive detection way of stress effects.

Construction of hu-PBL/SCID chimeras and development of EBV-related lymphomas.

OBJECTIVE: To construct hu-PBL/SCID chimeras and to investigate the development of lymphoma and oncogenicity of the Epstein-Barr virus (EBV). METHODS: Human peripheral blood lymphocytes (PBLs) were isolated from healthy adult donors and transplanted intraperitoneally into severe combined immunodeficient (SCID) mice. Mice with hu-PBL engraftment from healthy EBV seronegative donors were injected intraperitoneally with EBV-containing supernatant from suspension culture of B95-8 cell line (active infection), whereas mice receiving lymphocytes from healthy EBV seropositive donors were not re-infected with B95-8 derived EBV (latent infection). Pathological examination and molecular analysis were performed on experimental animals and induced neoplasms. RESULTS: In the early stage of this experiment, 12 mice died of acute graft-versus-host disease, mortality was 34.3% (12/35 mice) with an average life span of 17.5 days. In 19 survival hu-PBL/SCID chimeric recipients from 12 healthy donors, tumor incidence was 84.2% (16/19 mice). The average survival time of tumor-bearing mice was 65.5 days. EBV-related neoplasms in SCID mice were nodular tumors with aggressive and fatal features. Histological morphology of tumors exhibited diffuse large cell lymphomas. Immunohistochemistry revealed that LCA (CD45) and L26 (CD20) were positive, but both PS1 (CD3) and UCHL-1 (CD45RO) were negative, and EBV products ZEBRA, LMP1, and EBNA2 were expressed in a small number of tumor cells. EB virus particles were seen in the nuclei of some tumor cells by electron microscopy, and EBV DNA could be amplified in the tumor tissues by PCR. In situ hybridization indicated that the nuclei of tumor cells contained human-specific Alu sequence. CONCLUSIONS: EBV-induced tumors were human B-cell malignant lymphomas. We obtained direct causative evidence dealing with EBV-associated tumor deriving from normal human cells.

[Comparation of inflammation between wild mice and severe combined immunodeficiency mice with endotoxemia induced by lipopolysaccharide].

AIM: To compare the inflammation between wild BALB/c mice and mice with severe combined immunodeficiency (SCID) with endotoxemia induced by lipopolysaccharide (LPS). METHODS: Endotoxemia models of wild and SCID mice were established by injecting LPS intraperitoneally. Serum was taken before and 3 h, 6 h, 12 h after injecting LPS, liver and lung were taken 12 h after injecting LPS. Alanine transarninase (ALT), aspartate aminotransferase (AST) and blood urea nitrogen (BUN) levels were measured by automatic biochemical analyzer. Liver and lung inflammation injury were observed by H.E staining. TNF-α, IFN-γ, IL-6 and MCP-1 levels in serum were detected by Cytometric Bead Array (CBA). RESULTS: (1) All of SCID mice (8/8) were dead at 12-24 h after injecting LPS, and only one BALB/c mouse (1/8) was dead. (2) ALT and AST levels of SCID mice 12 h after injecting LPS were higer than those of BALB/c mice(P<0.05), but there was no difference of BUN levels between them. (3) The blind liver and lung pathology scores of SCID mice were higher than those of BALB/c mice (P<0.05). (4) TNF-α, IFN-γ, IL-6 and MCP-1 levels in serum at 3 h, 6 h, 12 h after injecting LPS increased significantly, and the cytokine levels of SCID mice were higher than those of BALB/c mice(P<0.05). CONCLUSION: SCID mice don't only excessively secrete inflammatory cytokines after injecting LPS, but also lead to more severe endotoxemia and inflammation injury of organs, which are the important cause of mouse death. The above results also show that the adjustment deficiency of adaptive immunoresponse, abnormal augmentation of innate immunoresponse may be an important cause of severe SIRS of endangering life.

[Benign fibrous histiocytoma involving the skull: a case report and literature review].

OBJECTIVE: Benign fibrous histiocytomas (BFH) represent a rare group of tumors with a common origin from the tissue histiocytes, often causing pain and space-occupying effect. BFH of bone causes diagnostic difficulties due to its atypical clinical symptoms, radiographic features and cytological characteristics, which can be easily confused with other benign lesions such as non-ossifying fibroma (NOF), giant cell tumor (GCT), and fibrous dysplasia. The lesions are prone to relapse, and the patients often show poor response to radiotherapy and chemotherapy, therefore radical lesion resection should be the therapeutic target of this disease. This paper reported a case of BFH involving the skull and reviewed the associated literatures.

[Callus induction and regeneration from mature seeds of indica rice minghui 63 and anti-fungal assay of transgenic rice plants].

A large number of callus from mature seeds of indica rice minghui 63 were obtained through pre-induction on medium with 2 mg/L 2,4-D but without inorganic and organic components for 9 days. Trichosanthin gene was transferred into indica rice minghui 63 by using agrobacterium with the help of bombardment and the transgenic plants were obtained by inducing regeneration. Southern and Western blot analysis showed that the trichosanthin gene had been transferred into genome of minghui 63 and expressed in rice plants. The anti-fungal assay suggested that transgenic rice plants enhanced resistance to infection of Pyricularia oryzae.