Transcription of Drosophila mobile element gypsy (mdg4) in heat-shocked cells

AbstractDrosophila melanogaster Schneider 2 line cultured cells were subjected to stable transformation by co-transfection with two plasmids, one of which conferred G418 resistance and another which contained the Drosophila retrotransposon, gypsy (mdg4), under the control of the heat-shock protein 70 promoter. Transcription of the introduced constructs, as well as of endogenous gypsy, was examined under the condition of heat shock. Active degradation of pre-existing gypsy transcripts was observed. During recovery, gypsy transcription was restored, but its termination and/or 3'-end processing became aberrant

Promoting in Tandem: The Promoter for Telomere Transposon HeT-A and Implications for the Evolution of Retroviral LTRs

AbstractHeT-A elements are non–long terminal repeat (non-LTR) retrotransposons found in head-to-tail arrays on Drosophila chromosome ends, where they form telomeres. We report that HeT-A promoter activity is located in the 3′ end of the element, unlike the 5′ location seen for other non-LTR retrotransposons. In HeT-A arrays the 3′ sequence of one element directs transcription of its downstream neighbor. Because the upstream promoter has the same sequence as the 3′ end of the transcribed element, the HeT-A promoter is effectively equivalent to a 5′ LTR in both structure and function. Retroviruses and LTR retrotransposons have their promoters and transcription initiation sites in their 5′ LTRs. Thus HeT-A appears to have the structure of an evolutionary intermediate between non-LTR and LTR retrotransposons

The study of acute and chronic toxicity of the sodium-, calcium-, iron-polygalacturonate pharmacological substance in rabbits

The purpose of this study is the assessment of the acute and chronic toxicity of pharmacological substance sodium, calcium, iron-polygalacturonate (PG Na,Ca,Fe) in rabbits as one of the stages of preclinical studies. We studied an acute and chronic oral toxicity of PG Na,Ca,Fe, which stimulates the process of hemopoiesis, in male and female rabbits of the “Chinchilla”. According to the results of the study of acute toxicity of PG Na,Ca,Fe, treating with it the rabbits of both sexes in doses of 0.5–5 g/kg has no toxic effect (LD50 greater than 5 g/kg). The histostructure of studied organs of animals, treated with preparations in a dose of 5 g/kg, did not differ from that of the animals of the control group. This study allow to classify PG Na,Ca,Fe as a preparation of the 6th class with respect to harmless drugs. An estimate of the chronic toxicity of PG Na,Ca,Fe at administration of preparation in the form of boluses to rabbits in doses 0.025, 0.262 and 0.5 g/kg of the body weight demonstrated that the general condition and behavior of animals did not differ from the norm. The data of hematological and biochemical studies of blood serum and urine, electrocardiographic studies, the study of the mass coefficients of the internal organs of the experimental rabbits, treated with PG Na,Ca,Fe in the mentioned doses for 60 days, compared to those obtained in the 30-day post-observation period, did not show significant changes with respect to the control and intact group of rabbits. Keywords: Na-,Ca-,Fe-polygalacturonate, Pectin polysaccharides modification, Acute toxicity, Chronic toxicity, Antianemic preparatio