Mechanisms of excising the P-element in a model system at the yellow locus of Drosophila melanogaster]

Patterns of excision of a single P element were studied in a model system of the yellow locus. The data obtained were in good agreement with the generally accepted SDSA (synthesis-dependent strand annealing) model. Specific features of P element excision in the presence of two tandemly repeated copies are presented. The pattern of P element excision depended on the sequences surrounding the insertion site and on the number of its additional copies present in the genome.     

High-dose γ-irradiation enhances the expression of a transgene controlled by the immediate-early CMV promoter in stably transfected tumor cells

γ-irradiation is commonly used to inactivate whole-cell anticancer vaccines containing viable tumor cells. To evaluate the effect of γ-irradiation on transgene expression in tumor cells, human and mouse cell lines were stably transfected with constructs expressing the granulocyte macrophage colony-stimulating factor (GM-CSF) or green fluorescent protein (GFP) gene under the control of the immediate-early CMV promoter. Irradiation of cells at 20–100 Gy caused a loss of proliferation capacity and gradual cell death, with the survival depending on the irradiation dose. G2/M cells accumulated in irradiated cultures, while the portion of S-phase cells was reduced. Surviving cells displayed activation of β-galactosidase and morphological changes associated with cell senescence. Mitochondrial dehydrogenase activity did not change with the irradiation dose. Irradiated cells retained transgene expression. Moreover, the amount of secreted GM-CSF and GFP production significantly increased after γ-irradiation, up to tenfold in cells exposed to 100 Gy. Transgene expression increased gradually and positively correlated with the total irradiation dose. The results demonstrate that γ-irradiation at 100 Gy is optimal for whole-cell anticancer vaccine inactivation.     

Cell wars fought with nanoweapons

We consider examples of the recently demonstrated means of attack and defense in the host versus cancer combat at the cellular level that involve interactions between widespread multifunctional proteins Tag7/PGRP-S, Hsp70, and Mts1/S100A4.     

The Amaryllidaceae alkaloids: an untapped source of acetylcholinesterase inhibitors

Phytochemistry Reviews - The AChE inhibitory activity of alkaloid extracts and compounds has been in the focus of research on the plants of Amaryllidoideae subfamily since the approval of...     

Structural organization of human simian virus 40 chromosomes. I. Heterogeneity and composition of nuclear DNA-protein complexes at different stages of lytic infection

Extraction of the purified nuclei of SV40 infected cells reveals a heterogeneous set of viral DNA-protein complexes. Earlier, the authors have shown the possibility of nuclear particles extraction being indistinguishable from mature SV40 virions. In the present work, structural intermediates of virus maturation from free minichromosomes through replicative complexes to immature virion particles have been analyzed. The fractionation of viral complexes by non-denaturing agarose gel electrophoresis has been employed. The protein composition of the complexes as determined by two-dimensional gel electrophoresis indicates that five histone fractions including H1 are present during minichromosome maturation to the chromosome of the mature virion.     

Paranoplocephala aquatica n. sp. (Cestoda, Anoplocephalidae) from Arvicola terrestris and Ondatra zibethica (Rodentia), with redescriptions and comments on related species

Paranoplocephala aquatica n. sp. is described from Arvicola terrestris and Ondatra zibethica (Rodentia, Cricetidae) in Bulgaria. The new species is characterised by a band-like strobila, a uterus forming a fine reticulate structure in the early stages of development, numerous testes (approximately 92) situated mainly aporally to the ovary in both the median and the aporal lateral fields, few testes positioned anterior to the ovary and genital ducts, the prominent asymmetrical situation of the female organs, the length of the vagina c. 0.65–0.68 of the length of the cirrus-sac, and the external seminal vesicle covered by a cellular sleeve. The new species is distinguished from P. ondatrae, P. macrocephala, P. dasymidis and P. sciuri. The specimens from O. zibethica reported as P. ondatrae by Tenora & Murai (1980) and as Aprostatandrya macrocephala by Spasskii et al. (1951) are believed to belong to P. aquatica. The type-series of P. ondatrae and P. macrocephala are redescribed and figured; metric data and an illustration of the holotype of P. sciuri are presented. The genus Paranoplocephala sensu Tenora et al. (1986) is regarded as a heterogeneous group because of the two patterns of uterine development in the species studied. Taxonomic criteria used for distinguishing the genera Andrya and Paranoplocephala, and some criteria applicable at the species level, are discussed.