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At least 793 records · Page 44Linked to original sources
PubMed2004

Aspochalamins A-D and aspochalasin Z produced by the endosymbiotic Fungus aspergillus niveus LU 9575. I. Taxonomy, fermentation, isolation and biological activities.

Aspochalamins A-D, a family of new cytochalasan antibiotics have been isolated from Aspergillus niveus, an endosymbiotic fungus isolated from the gut of a woodlouse belonging to the family Trichoniscidae. Besides aspochalamins, aspochalasin Z, a new member of the aspochalasin family, as well as the known mycotoxins aspochalasin D and citreoviridins A/C and B were isolated from the mycelium. Aspochalamins showed cytostatic effects towards various tumor cell lines and a weak antibacterial activity against Gram-positive bacteria.

Anti-Bacterial Agents↗
PubMed1992

[The effect of the UV microirradiation of the centrosome on cell behavior. III. The ultrastructure of the centrosome after irradiation].

One of the spindle poles of mitotic PK cells was irradiated with UV microbeam in metaphase or in anaphase. Electron microscopy showed that immediately after irradiation the microtubules around the centrosome were maintained, and that the ultrastructure of both irradiated and nonirradiated poles was similar. After microirradiation of the centrosome in metaphase, the mitotic halo around this centrosome was retained, but in due time the number of microtubules was getting less compared to that around the nonirradiated centrosome. When daughter cells with irradiated centrosomes are passing into the interphase, their centrioles are not separated from each other, no primary cilia are formed, and no replication of centrioles occurs. In the interphase cells with irradiated centrosomes, satellites are formed on the active centriole, but centrosome-attached microtubules are practically absent.

Anaphase↗
PubMed1991

UV-microbeam irradiations of the mitotic spindle: spindle forces and structural analysis of lesions.

Mitotic PtK1 spindles were UV irradiated (285 nm) during metaphase and anaphase between the chromosomes and the pole. The irradiation, a rectangle measuring 1.4 x 5 microns parallel to the metaphase plate, severed between 90 and 100% of spindle microtubules (MTs) in the irradiated region. Changes in organization of MTs in the irradiated region were analyzed by EM serial section analysis coupled with 3-D computer reconstruction. Metaphase cells irradiated 2 to 4 microns below the spindle pole (imaged by polarization optics) lost birefringence in the irradiated region. Peripheral spindle fibers, previously curved to focus on the pole, immediately splayed outwards when severed. We demonstrate via serial section analysis that following irradiation the lesion was devoid of MTs. Within 30 s to 1 min, recovery in live cells commenced as the severed spindle pole moved toward the metaphase plate closing the lesion. This movement was concomitant with the recovery of spindle birefringence and some of the severed fibers becoming refocused at the pole. Ultrastructurally we confirmed that this movement coincided with bridging of the lesion by MTs presumably growing from the pole. The non-irradiated half spindle also lost some birefringence and shortened until it resembled the recovered half spindle. Anaphase cells similarly irradiated did not show recovery of birefringence, and the pole remained disconnected from the remaining mitotic apparatus. Reconstructions of spindle structure confirmed that there were no MTs in the lesion which bridged the severed spindle pole with the remaining mitotic apparatus. These results suggest the existence of chromosome-to-pole spindle forces are dependent upon the existence of a MT continuum, and to a lesser extent to the loss of MT initiation capacity of the centrosome at the metaphase/anaphase transition.

Anaphase↗
PubMed1990

[Y. pestis phage of a new serovar].

Phage II, isolated from Y. pestis strain 2247 obtained from a desert focus in Central Asia, has been studied. The phage is classified with moderate phages and essentially differs from moderate phages of serovar 2. The sources of isolation, high specificity and the absence of common serological features with presently known Y. pestis phages of serovars 1 and 2 permit the classification of this phage with new serovar 3 of Y. pestis phages.

Animals↗
PubMed1990

[Covalent-bound aggregates of equine venezuelan encephalomyelitis virus induced by UV-irradiation].

Formation of Venecuelan equine encephalomyelitis virus (VEE) aggregates induced by UV-light has been studied. The high doses of UV-irradiation induced the protein-protein cross-links resulting in formation of fast sedimenting viral structures. The latter structures are supposed to be presented by the aggregates of several virions linked by the UV-light induced RNA-protein and protein-protein covalent bonds. The lesions in the fine structure of virion envelope was registered by the electron microscopy technique.

Encephalitis Virus, Venezuelan Equine↗
PubMedDate not supplied

[Comparative characteristics of spherical and filamentous virions of influenza virus type A].

An analysis of fractions of a reassortant of A/WSN/33 and A/duck/Hochimin/014/78 strains enriched with spherical and filamentous virions showed that spherical and filamentous virus particles differed by sucrose density gradient. The relative content of nucleocapsid protein in filamentous virions was slightly lower than in spherical ones which might be due to different volume/surface ratio of these particles. The results of UV-inactivation of filamentous and spherical virions suggest that the filamentous particles are multigenomic.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

Hyperkeratosis lenticularis perstans: report on three cases.

Three women with hyperkeratosis lenticularis perstans (HLP) are described. The lesions developed after the age of 45 and there was no family history of this disease. The possible role of UV-light in the pathogenesis of this disease is discussed.

Aged↗
PubMed1986

Changes with time in Langerhans cell number, ATPase reactivity and morphology in murine epidermis after exposure to UVB.

Effects on Langerhans cells of a single 200 mJ/cm2 dose of 284-316 nm UVB were studied in the dorsal epidermis of CBA/H mice. ATPase-positive cells were counted using light microscopy and compared with numbers of cells containing Birbeck granules. In interfollicular epidermis from untreated mice 633 +/- 20 (mean +/- S.E., n = 30) ATPase-positive cells/mm2 were found. By 3 days after UVB treatment, the number of ATPase-positive cells decreased by 90%, whilst the Birbeck granule-containing cell population was only reduced by 40% and very few cells had ultrastructural damage, suggesting that many Langerhans cells lost ATPase marker but remained intact. 7 d after irradiation there were 50% more cells with Birbeck granules than in controls, but the number of cells bearing ATPase remained below normal. ATPase-positive cell numbers approached normal only after a further 2-3 weeks. Langerhans cell responses after UVB differed from those previously found after X-irradiation.

Adenosine Triphosphatases↗
PubMed1985

UV-induced structural changes in chromatin.

UV-induced structural alterations of chromatin were studied by means of CD, electron microscopic, and gel electrophoretic measurements. The results indicate that chromatin undergoes serious structural changes after irradiation even at very low fluences. In the low fluence range the structural transitions from the higher ordered chromatin structure to the unfolded state occur without detectable changes in the content of histone H1 and of the core histones. Histone H1 disappears only at fluences above 10 kJ/m2. Furthermore, DNA in chromatin is much more sensitive against UV-irradiation and shows a higher degree of strand scission relative to free DNA. While fragmentation in free DNA occurs at fluences above 15 kJ/m2, it occurs even at 5.5 kJ/m2 in the case of chromatin. The biological meaning of the observed UV-induced structural alterations of chromatin is discussed.

Animals↗