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41.
V. Kuete H.M. Poumale Poumale A.N. Guedem Y. Shiono R. Randrianasolo B.T. Ngadjui 《South African Journal of Botany》2010
This study was designed to evaluate the antimycobacterial, antibacterial and antifungal activities of the methanol extract from the stem bark of Thecacoris annobonae Pax & K. Hoffm, that of aristolochic acid I (1) and other isolated compounds. The microplate alamar blue assay (MABA) and the broth microdilution method were used to determine the minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of the above samples. The H+-ATPase-mediated proton pumping assay was used to evaluate a possible mechanism of action for both the methanol extract and aristolochic acid I. The results of the MIC determinations showed that the methanol extract and aristolochic acid I prevent the growth of all studied organisms. The results obtained in this study also showed that the methanol extract as well as aristolochic acid I inhibited the H+-ATPase activity. The overall results provided evidence that the methanol extract of T. annobonae might be a potential source of new antimicrobial drug against tuberculosis, and some bacterial and fungal diseases, but should be consumed with caution, bearing in mind that the main active component, aristolochic acid I is a potentially toxic compound. 相似文献
42.
Hiroshi Shiraishi Hideaki Okamoto Hiromitsu Hara Hiroki Yoshida 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Various forms of cell death, such as apoptotic, autophagic and non-lysosomal types, are implicated in normal physiological processes. Apoptotic protease activating factor 1 (Apaf1) is an important component of the intrinsic apoptotic pathway. Deficiency of Apaf1 results in an accumulation of neural progenitor cells (NPCs) in the developing central nervous system and thus, in perinatal lethality. A small percentage of the mutant mice, however, are viable and grow to maturity. The occurrence of such normal mutants implicates alternative cell death pathways during neurogenesis.Methods
NPCs prepared from wild-type or Apaf1-deficient embryos were cultured in growth factor-deprived medium and examined for cell death, caspase activation and morphological alterations. Generation of reactive oxygen species (ROS) and the effects of antioxidants were examined.Results
Wild-type NPCs underwent apoptosis within 24 hours of withdrawal of epidermal growth factor (EGF) or insulin, whereas Apaf1-deficient NPCs underwent cell death but showed no signs of apoptosis. Autophagy was not necessarily accompanied by cell death. Cell death of the Apaf1-deficient NPCs resembled necroptosis—necrosis-like programmed cell death. The necroptosis inhibitor necrostatin-1, however, failed to inhibit the cell death. ROS accumulation was detected in NPCs deprived of growth factors, and an antioxidant partially suppressed the non-apoptotic cell death of Apaf1-deficient NPCs.Conclusions
These data indicate that after withdrawal EGF or insulin withdrawal, the Apaf1-deficient cells underwent non-apoptotic cell death. ROS generation may partially participate in the cell death.General Significance
Non-apoptotic cell death in NPCs may be a compensatory mechanism in the developing CNS of Apaf1-deficient embryos. 相似文献43.
44.
Stress responses in Salix gracilistyla cuttings subjected to repetitive alternate flooding and drought 总被引:2,自引:0,他引:2
To determine the tolerance of Salix gracilistyla to repetitive alternate flooding and drought, we measured leaf stomatal conductance, pre-dawn water potential, osmotic adjustment,
and biomass production under greenhouse conditions. We used a control and nine crossed treatments (F1-D1–F3-D3) in which we
combined 1-, 2-, or 3-week floodings (F) and droughts (D). Leaf stomatal conductance was lowest in 3 weeks of flooding or
drought when the preceding event (flood or drought) was also of a 3-week duration. Leaf pre-dawn water potential was reduced
in 3 weeks of drought when preceded by 2 or 3 weeks of flooding. Cuttings had slight osmotic adjustments in repetitions of
long floodings and droughts. During longer durations of drought in crossed experiments, plants had low root and shoot mass,
few hypertrophic lenticels, and reduced leaf mass; when flooding duration increased in crossed experiments, root mass was
reduced, there were more hypertrophic lenticels, and the leaf area was reduced. Cuttings achieved stress tolerance by inhibition
of transpiration, osmotic adjustment, reduction of transpiration area, and development of hypertrophic lenticels. Stress tolerance
was weak when repetitive 2- or 3-week floodings were combined with 3-week droughts. The duration of flooding and drought periods
under which S. gracilistyla achieves stress tolerance may be critical in determining distributions along riverbanks. 相似文献
45.
46.
Yukihiro Kabeya Hiromitsu Nakanishi Kenji Suzuki Takanari Ichikawa Youichi Kondou Minami Matsui Shin-ya Miyagishima 《BMC plant biology》2010,10(1):57
Background
Reminiscent of their free-living cyanobacterial ancestor, chloroplasts proliferate by division coupled with the partition of nucleoids (DNA-protein complexes). Division of the chloroplast envelope membrane is performed by constriction of the ring structures at the division site. During division, nucleoids also change their shape and are distributed essentially equally to the daughter chloroplasts. Although several components of the envelope division machinery have been identified and characterized, little is known about the molecular components/mechanisms underlying the change of the nucleoid structure. 相似文献47.
The adenovirus vector is very attractive tool not only for the gene therapy but also for the basic sciences. However, because a construction method of this vector had been complex, only limited scientists had constructed and enjoyed the benefits. Recently, various methods were developed and the researchers came to be able to choose an efficient method, which is the COS-TPC method, or a concise procedure, which is the intact-genome transfection method (in vitro ligation method). Here we described not only these methods but also new method to construct the various Ads simultaneously using the recombinase-mediated cassette exchange (RMCE) by the site-specific recombinase. And also we want to refer the possibility to the worth of the vector, especially the vector of the expression-switch. 相似文献
48.
Takayama H Yaegashi Y Kitajima M Han X Nishimura K Okuyama S Igarashi K 《Bioorganic & medicinal chemistry letters》2007,17(17):4729-4732
We have developed a new class of N-methyl-d-aspartate (NMDA) channel blockers having a conjugate structure that consists of a nitrogenous heterocyclic head and a tetraamine tail. Among them, dihydrodibenzazepine-homospermine conjugate (8) exhibited potent antagonistic activity at NR1/NR2A or NR1/NR2B NMDA subtype receptors compared with the lead compound, AQ343 (1), or memantine, as well as weak cytotoxicity. Its superior biological profiles compared with known compounds point to its potential use as therapeutic agents for neurological disorders. 相似文献
49.
50.
The E3 ligase HACE1 is a critical chromosome 6q21 tumor suppressor involved in multiple cancers 总被引:1,自引:0,他引:1
Zhang L Anglesio MS O'Sullivan M Zhang F Yang G Sarao R Mai PN Cronin S Hara H Melnyk N Li L Wada T Liu PP Farrar J Arceci RJ Sorensen PH Penninger JM 《Nature medicine》2007,13(9):1060-1069
Transformation and cancer growth are regulated by the coordinate actions of oncogenes and tumor suppressors. Here, we show that the novel E3 ubiquitin ligase HACE1 is frequently downregulated in human tumors and maps to a region of chromosome 6q21 implicated in multiple human cancers. Genetic inactivation of HACE1 in mice results in the development of spontaneous, late-onset cancer. A second hit from either environmental triggers or genetic heterozygosity of another tumor suppressor, p53, markedly increased tumor incidence in a Hace1-deficient background. Re-expression of HACE1 in human tumor cells directly abrogates in vitro and in vivo tumor growth, whereas downregulation of HACE1 via siRNA allows non-tumorigenic human cells to form tumors in vivo. Mechanistically, the tumor-suppressor function of HACE1 is dependent on its E3 ligase activity and HACE1 controls adhesion-dependent growth and cell cycle progression during cell stress through degradation of cyclin D1. Thus, HACE1 is a candidate chromosome 6q21 tumor-suppressor gene involved in multiple cancers. 相似文献