肝细胞生长素的某些研究进展

肝脏具有巨大的再生能力。动物实验及临床研究表明,将肝脏切除2/3后,肝脏可在短期内恢复到原体积,功能基本保持不变。早在60年代人们就曾推测,血液中可能存在某种物质能刺激和促进肝细胞的再生。1982年Strain等最先提出血小板中含有对肝脏具有刺激作用的生长因子。1983年Michalopoulos、Nakamura、Rusell等几乎同时在各自不同的三个实验中发现活组织中存在能刺激肝细胞DNA合成的物质。随后Golda等在暴发性肝衰患者的血液中发现同样的活性物质。但到1989年才对这一物质的分子结构有了较完整的认识,并因其对肝细胞具有强力的促有丝分裂作用而将其命名为Hepatocyte Growth Factor (HGF)中译名有肝细胞生长素、促肝细胞生长素及肝细胞再生因子等。

Dynamic distribution of TTK in HeLa cells: insights from an ultrastructural study

Entry into mitosis is driven by signaling cascades of mitotic kinases.Our recent studies show that TTK,a kinetochore-associated protein kinase,interacts with CENP-E,a mitotic kinesin located to corona fiber ofkinetochore.Using immunoelectron microscopy,here we show that TTK is present at the nuclear pore adjacent complex of interphase HeLa cells.Upon nuclear envelope fragmentation,TTK targets to the outermostregion of the developing kinetochores ofmonoorient chromosome as well as to spindle poles.After stable attachment,throughout chromosome congression,TTK is a constituent of the corona fibers,extending up to 90 nm away from the kinetochore outer plate.Upon metaphase alignment,TTK departs from the kinetochore and migrates toward the centrosomes.Taken together,this evidence strongly supports a model in which TTK functions in spindle checkpoint signaling cascades at both kinetochore and centrosome.

Predicting the Reproduction Strategies of Several Microalgae Through Their Genome Sequences

Documenting the sex and sexual reproduction of the microalgae is very difficult, as most of the results are based on the microscopic observation that can be heavily influenced by genetic, physiological and environmental conditions. Understanding the reproduction strategy of some microalgae is required to breed them in large scale culture industry. Instead of direct observation of sex and sexual reproduction under microscope, the whole set or the majority of core meiosis genes may evidence the sex and sexual reproduction in the unicellular algae, as the meiosis is necessary for maintaining the genomic stability and the advantages of genetic recombination. So far, the available genome sequences and bioinformatic tools （in this study, homolog searching and phylogenetic analysis） allow us to propose that at least 20 core meiosis genes （among them 〉6 must be meiosis specific） are enough for an alga to maintain its sexual reproduction. According to this assumption and the genome sequences, it is possible that sexual reproduction was carried out by Micromonas pusilla and Cyanidiosehyzon merolae, while asexual reproduction was adopted by Bigelowiella natans, Guillardia theta, Nannochloropsis gaditana, N. oeeanica, Chlorella variablis, Phaeodactylum tricornutum and Thalassiosira pseu- donana. This understanding will facilitate the breeding trials of some economic microalgae （e.g., N. gaditana, N. oceanica, C. vari- ablis and P. tricornutum）. However, the reproduction strategies of these microalgae need to be proved by further biological experiments.

Experimental study of gemcitabine combination with radiation in vitro on a highly metastatic human ovarian cancer cell line HO-8910PM

Objective： The aim of the study was to investigate the mechanism of gemcitabine （GEM） combination with radiation on the high metastasis human ovarian cancer cell line （HO-8910PM）. Methods： Human ovarian cancer cell line HO- 8910PM was treated with different concentrations of gemcitabine for 24 h, then the cells were counted. In the study of GEM combination with radiation, an efficiency of colony formation was observed; the cell cycle and apoptosis were analyzed by flow cytometry; the experiment of depend on the time and its radio sensitivity were observed by using mitotic index with the cells for each 24, 48, 72 and 96 h after experiment. Results： It suggested that the GEM had an inhibition effect on the human ovarian cancer cell line. The alive cell numbers were decreased by following a height of GEM concentration. When GEM in combina- tion with a radiation, the suppression was significantly increased than that of single GEM therapy. The efficiency of colony formation was significantly lower, under this condition the cell could be arrested at G0-G1 phase and could be decreased to enter into the S phase; the apoptosis percentage could be significantly increased; especially, under the 4 Gy and 6 Gy doses the cell apoptosis was more obvious. GEM combination with radiation had depended on the time to the cells; mitotic index of the calls in combination group was observed significantly lower than that of single GEM therapy or single radiation, and this showed that it had an effect of radiosensitivity. Conclusion： The GEM has a significant growth inhibition on the human ovarian cancer cells, GEM combination with radiation could induce HO-8910PM cell occurred arrested and apoptosis. It has depended on the time and has a radiosensitivity effect. The result shows that it is a better method to treat the human ovarian cancer by using radiotherapy combined with gemcitabine.

Foxn4:A multi-faceted transcriptional regulator of cell fates in vertebrate development

Vertebrate development culminates in the generation of proper proportions of a large variety of different cell types and subtypes essential for tissue,organ and system functions in the right place at the right time.Foxn4,a member of the forkhead box/winged-helix transcription factor superfamily,is expressed in mitotic progenitors and/or postmitotic precursors in both neural(e.g.,retina and spinal cord)and non-neural tissues(e.g.,atrioventricular canal and proximal airway).During development of the central nervous system,Foxn4 is required to specify the amacrine and horizontal cell fates from multipotent retinal progenitors while suppressing the alternative photoreceptor cell fates through activating Dll4-Notch signaling.Moreover,it activates Dll4-Notch signaling to drive commitment of p2 progenitors to the V2b and V2c interneuron fates during spinal cord neurogenesis.In development of non-neural tissues,Foxn4 plays an essential role in the specification of the atrioventricular canal and is indirectly required for patterning the distal airway during lung development.In this review,we highlight current understanding of the structure,expression and developmental functions of Foxn4 with an emphasis on its cell-autonomous and non-cell-autonomous roles in different tissues and animal model systems.