Search results for "iOS"

Spermatocytes of the caddisfly Potamophylax rotundipennis (Trichoptera, Insecta): a fine structure study with emphasis on synaptonemal complex plates…

1996

Abstract Electron microscopy of ultrathin sections was used to study the restructuring of primary spermatocytes in a caddisfly, Potamophylax rotundipennis (Limnephilidae). Spindle structure was also examined using light microscopy of dividing spermatocytes lysed in a microtubule-stabilizing buffer. The bulk of pachytene spermatocytes was usual in that the nuclei contained tripartite synaptonemal complexes (SCs). The SCs were attached end-on to the inner face of the nuclear envelope and loosely surrounded by electron-dense chromatin. Cells of this type gave rise to late prophase I spermatocytes, where SCs were missing and chromatin condensation was advanced. By metaphase I, a conventional bi…

Ordered networks of rat hippocampal neurons attached to silicon oxide surfaces.

2001

The control of neuronal cell position and outgrowth is of fundamental interest in the development of applications ranging from cellular biosensors to tissue engineering. We have produced rectangular networks of functional rat hippocampal neurons on silicon oxide surfaces. Attachment and network formation of neurons was guided by a geometrical grid pattern of the adhesion peptide PA22-2 which matches in sequence a part of the A-chain of laminin. PA22-2 was applied by contact printing onto the functionalised silicon oxide surface and was immobilised by hetero-bifunctional cross-linking with sulfo-GMBS. Geometric pattern matching was achieved by microcontact printing using a polydimethylsiloxa…

Selective permeabilization of infected host cells with pore-forming proteins provides a novel tool to study protein synthesis and viability of the in…

2001

Yeast mRNA cap-binding protein Cbc1/Sto1 is necessary for the rapid reprogramming of translation after hyperosmotic shock.

2011

Global translation is inhibited in Saccharomyces cerevisiae cells under osmotic stress; nonetheless, osmostress-protective proteins are synthesized. We found that translation mediated by the mRNA cap-binding protein Cbc1 is stress-resistant and necessary for the rapid translation of osmostress-protective proteins under osmotic stress.

Characteristic ERK1/2 signaling dynamics distinguishes necroptosis from apoptosis

2021

International audience; ERK1/2 involvement in cell death remains unclear, although many studies have demonstrated the importance of ERK1/2 dynamics in determining cellular re- sponses. To untangle how ERK1/2 contributes to two cell death programs, we investigated ERK1/2 signaling dynamics during hFasL-induced apoptosis and TNF-induced necroptosis in L929 cells. We observed that ERK1/2 inhibition sensi- tizes cells to apoptosis while delaying necroptosis. By monitoring ERK1/2 activity by live-cell imaging using an improved ERK1/2 biosensor (EKAR4.0), we reported differential ERK1/2 signaling dynamics between cell survival, apoptosis, and nec- roptosis. We also decrypted a temporally shifted …

Novel [1,2,3]triazolo[1,5-a]pyridine derivatives are trypanocidal by sterol biosynthesis pathway alteration.

2019

Aim: To study a new series of [1,2,3]triazolo[1,5-α]pyridine derivatives as trypanocidal agents because current antichagasic pharmacologic therapy is only partially effective. Materials & methods: The effect of the series upon Trypanosoma cruzi epimastigotes and murine macrophages viability, cell cycle, cell death and on the metabolites of the sterol biosynthesis pathway was measured; also, docking in 14α-demethylase was analyzed. Results: Compound 16 inhibits 14α-demethylase producing an imbalance in the cholesterol/ergosterol synthesis pathway, as suggested by a metabolic control and theoretical docking analysis. Consequently, it prevented cell proliferation, stopping the cellular cy…

Pyridinedicarboxylates, the first mechanism-derived inhibitors for prolyl 4-hydroxylase, selectively suppress cellular hydroxyprolyl biosynthesis. De…

1987

Two pyridinedicarboxylates, predicted [Hanauske-Abel (1983) M.D.-Ph.D. Thesis, Philipps Universität Marburg] and later found to be potent reversible inhibitors of purified prolyl 4-hydroxylase [Majaama, Hanauske-Abel, Günzler & Kivirikko (1984) Eur. J. Biochem. 138, 239-245] were investigated with respect to their effect on hydroxyprolyl biosynthesis in the fibroblast/collagen and the macrophage/Clq systems, and the effect was compared with that of the iron chelator 2,2′-dipyridyl, the compound usually employed to inhibit cellular hydroxyprolyl formation. Only the enzyme-mechanism-derived pyridinedicarboxylates were highly selective inhibitors, and only they lacked overt cytotoxicity. M…

Expression of protein kinase C gene family members is temporally and spatially regulated during neural development in vitro.

1998

We used primary cultures of rat hippocampal neurons and PCC7-Mz1 cells to correlate the expression of the protein kinase C (PKC) gene family with specific events during neural differentiation. Multipotent PCC7-Mz1 embryonic carcinoma stem cells develop into a tissue-like pattern of neuronal, fibroblast-like and astroglial cells by all-trans retinoic acid (RA) treatment. Western blot analyses demonstrate that PKCalpha, betaI, gamma, theta, mu, lambda, and zeta were constitutively expressed but the expression of PKCbetaII, delta, epsilon, and eta was up-regulated three days after addition of RA when cells mature morphologically. While the protein levels of the PKC isoforms betaII, delta and e…

Spontaneous lymphokine synthesis by human blood mononuclear cells

1975

LYMPHOCYTES, after antigenic stimulation, may synthesise and release biologically active soluble factors other than antibodies. These mediators were termed lymphokines by Dumonde1, and the most extensively studied and best characterised are migration inhibitory factors which can inhibit the migration of macrophages or leukocytes: this is the property used for their in vitro bioassay. Apart from antigens, various other stimuli may trigger lymphokine synthesis by lymphocytes, for example, polyclonal mitogens2, anti-immunoglobulin or membrane Fc or C3-receptor reactions3,4. Furthermore, migration inhibitory activity has been found in the long term culture supernatants of some established lymph…

GTVcut for neuro-radiosurgery treatment planning: an MRI brain cancer seeded image segmentation method based on a cellular automata model

2018

Despite of the development of advanced segmentation techniques, achieving accurate and reproducible gross tumor volume (GTV) segmentation results is still an important challenge in neuro-radiosurgery. Nowadays, magnetic resonance imaging (MRI) is the most prominent modality in radiation therapy for soft-tissue anatomical districts. Gamma Knife stereotactic neuro-radiosurgery is a minimally invasive technology for dealing with inaccessible or insufficiently treated tumors with traditional surgery or radiotherapy. During a treatment planning phase, the GTV is generally contoured by experienced neurosurgeons and radiation oncologists using fully manual segmentation procedures on MR images. Unf…