82 research outputs found

    SHEEP BODY WEIGHT INFLUENCE ON REPRODUCTIVE PARAMETERS WHILE UNDER THE INCREASED DOSAGE OF GONADOTROPIC HORMONE DURING INDUCTION AND SYNCHRONIZATION OF ESTRUS IN ANESTRUS SEASON

    Get PDF
    Aim of this paper is to determine if there are differences in sexual reaction of mature Il d'france sheep depending on body weight of ewes that were treated with increased dosage of gonadotropic hormone by 250IU compared to usual dosage of 500IU that is given during induction and estrus synchronization during anestrus season. Total number of 99 ewes were treated, divided in to three weight groups depending on their body mass. First group were sheep whose body weight was within 40-50 kg limit, second group was between 50-60 kg and third group was sheep that had higher body weight than 60 kg (control group). All animals of all groups received intra vaginal sponges containing 30mg of fluorgestone acetate which remained within for 12 days. At the day of sponge removal each sheep received one dosage 750IU of gonadotropic hormone. Two days later β€œoffhand” mating was done.Obtained results show that from first group 49,06%; II 50,00% and III 65,50% of treated ewes had kids. Average fertility of sheep per treatment I, II and III was 134,61% for I group, which was close to lower expected fertility limit for this breed, however fertility of second group was 157,89% and third group 160,00% was within limits of expected fertility for this breed when it is kept in optimal conditions. Conclusion was that sheep of II and III group reacted better on applied treatment and therefore achieved satisfying fertility

    A Frequency Multiplier Based on Time Recursive Processing

    Get PDF
    This paper describes a digital frequency multiplier for a pulse rate. The multiplier is based on the recursive processing of the input and output periods and their time differences. Special emphasis is devoted to the techniques which provide the development of multipliers based on this principle. The circuit is defined by two system parameters. One is the ratio of two clock frequencies and the other is a division factor of a binary counter. The realization of the circuit is described. The region of the system parameters for the stable circuit is presented. The different aspects of applications and limitations in realization of the circuit are considered. All mathematical analyses are made using a Z transform approach. It is shown that the circuit can be also used in tracking and prediction applications. Computer simulations are performed to prove the correctness of the math and the whole approach

    Whole-Genome Analysis Reveals That Active Heat Shock Factor Binding Sites Are Mostly Associated with Non-Heat Shock Genes in Drosophila melanogaster

    Get PDF
    During heat shock (HS) and other stresses, HS gene transcription in eukaryotes is up-regulated by the transcription factor heat shock factor (HSF). While the identities of the major HS genes have been known for more than 30 years, it has been suspected that HSF binds to numerous other genes and potentially regulates their transcription. In this study, we have used a chromatin immunoprecipitation and microarray (ChIP-chip) approach to identify 434 regions in the Drosophila genome that are bound by HSF. We have also performed a transcript analysis of heat shocked Kc167 cells and third instar larvae and compared them to HSF binding sites. The heat-induced transcription profiles were quite different between cells and larvae and surprisingly only about 10% of the genes associated with HSF binding sites show changed transcription. There were also genes that showed changes in transcript levels that did not appear to correlate with HSF binding sites. Analysis of the locations of the HSF binding sites revealed that 57% were contained within genes with approximately 2/3rds of these sites being in introns. We also found that the insulator protein, BEAF, has enriched binding prior to HS to promoters of genes that are bound by HSF upon HS but that are not transcriptionally induced during HS. When the genes associated with HSF binding sites in promoters were analyzed for gene ontology terms, categories such as stress response and transferase activity were enriched whereas analysis of genes having HSF binding sites in introns identified those categories plus ones related to developmental processes and reproduction. These results suggest that Drosophila HSF may be regulating many genes besides the known HS genes and that some of these genes may be regulated during non-stress conditions

    Phylogeny Disambiguates the Evolution of Heat-Shock cis-Regulatory Elements in Drosophila

    Get PDF
    Heat-shock genes have a well-studied control mechanism for their expression that is mediated through cis-regulatory motifs known as heat-shock elements (HSEs). The evolution of important features of this control mechanism has not been investigated in detail, however. Here we exploit the genome sequencing of multiple Drosophila species, combined with a wealth of available information on the structure and function of HSEs in D. melanogaster, to undertake this investigation. We find that in single-copy heat shock genes, entire HSEs have evolved or disappeared 14 times, and the phylogenetic approach bounds the timing and direction of these evolutionary events in relation to speciation. In contrast, in the multi-copy gene Hsp70, the number of HSEs is nearly constant across species. HSEs evolve in size, position, and sequence within heat-shock promoters. In turn, functional significance of certain features is implicated by preservation despite this evolutionary change; these features include tail-to-tail arrangements of HSEs, gapped HSEs, and the presence or absence of entire HSEs. The variation among Drosophila species indicates that the cis-regulatory encoding of responsiveness to heat and other stresses is diverse. The broad dimensions of variation uncovered are particularly important as they suggest a substantial challenge for functional studies
    • …
    corecore