Повышение эффективности проведения геолого-технических мероприятий на нефтяных месторождениях Западной Сибири

Рассмотрены существующие методы ГТМ, проведен анализ особенностей разных ГТМ на месторождениях Западной Сибири, предложены инновационные методы по повышению их эффективности.Existing methods of geological and technical measures are considered, the analysis of the features of different geological and technical measures at fields in Western Siberia is carried out, innovative methods for increasing their efficiency are proposed

Odour-mediated orientation of beetles is influenced by age, sex and morph

The behaviour of insects is dictated by a combination of factors and may vary considerably between individuals, but small insects are often considered en masse and thus these differences can be overlooked. For example, the cowpea bruchid Callosobruchus maculatus F. exists naturally in two adult forms: the active (flight) form for dispersal, and the inactive (flightless), more fecund but shorter-lived form. Given that these morphs show dissimilar biology, it is possible that they differ in odour-mediated orientation and yet studies of this species frequently neglect to distinguish morph type, or are carried out only on the inactive morph. Along with sex and age of individual, adult morph could be an important variable determining the biology of this and similar species, informing studies on evolution, ecology and pest management. We used an olfactometer with motion-tracking to investigate whether the olfactory behaviour and orientation of C. maculatus towards infested and uninfested cowpeas and a plant-derived repellent compound, methyl salicylate, differed between morphs or sexes. We found significant differences between the behaviour of male and female beetles and beetles of different ages, as well as interactive effects of sex, morph and age, in response to both host and repellent odours. This study demonstrates that behavioural experiments on insects should control for sex and age, while also considering differences between adult morphs where present in insect species. This finding has broad implications for fundamental entomological research, particularly when exploring the relationships between physiology, behaviour and evolutionary biology, and the application of crop protection strategies

Human L1 Retrotransposition Is Associated with Genetic Instability In Vivo

AbstractRetrotransposons have shaped eukaryotic genomes for millions of years. To analyze the consequences of human L1 retrotransposition, we developed a genetic system to recover many new L1 insertions in somatic cells. Forty-two de novo integrants were recovered that faithfully mimic many aspects of L1s that accumulated since the primate radiation. Their structures experimentally demonstrate an association between L1 retrotransposition and various forms of genetic instability. Numerous L1 element inversions, extra nucleotide insertions, exon deletions, a chromosomal inversion, and flanking sequence comobilization (called 5′ transduction) were identified. In a striking number of integrants, short identical sequences were shared between the donor and the target site's 3′ end, suggesting a mechanistic model that helps explain the structure of L1 insertions

The disruption of JEN1 from Candida albicans impairs the transport of lactate

A lactate permease was biochemically identified in Candida albicans RM1000 presenting the following kinetic parameters at pH 5.0: Km 0.33 ± 0.09 mM and Vmax 0.85± 0.06 nmol s-1 mg dry wt-1. Lactate uptake was competitively inhibited by pyruvic and propionic acids; acetic acid behaved as a non-competitive substrate. An ORF homologous to Saccharomyces cerevisiae gene JEN1 was identified (CaJEN1). Deletions of both CaJEN1 alleles of C. albicans (resulting strain CPK2) resulted in the loss of all measurable lactate permease activity. No CaJEN1 mRNA was detectable in glucose-grown cells neither activity for the lactate transporter. In a medium containing lactic acid, CaJEN1 mRNA was detected in the RM1000 strain, and no expression was found in cells of CPK2 strain. In a strain deleted in the CaCAT8 genes the expression of CaJEN1 was significantly reduced, suggesting the role of this gene as an activator for CaJEN1 expression. Both in C. albicans and in S. cerevisiae cells CaJEN1-GFP fusion was expressed and targeted to the plasma membrane. The native CaJEN1 was not functional in a S. cerevisiae jen1Δ strain. Changing ser217-CTG codon (encoding leucine in S. cerevisiae) to a TCC codon restored the permease activity in S. cerevisiae, proving that the CaJEN1 gene codes for a monocarboxylate transporter.Deutsche Forschungsgemeinschaft (SFB 579).Fundação para a Ciência e a Tecnologia (FCT) - Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/1999/BME/36625 (Eixo 2, Medida 2.3, QCAIII-FEDER) , SFRH/BD/4699/2001 , PRAXIS XXI/BD/18198/98

The population biology and evolutionary significance of Ty elements in Saccharomyces cerevisiae

The basic structure and properties of Ty elements are considered with special reference to their role as agents of evolutionary change. Ty elements may generate genetic variation for fitness by their action as mutagens, as well as by providing regions of portable homology for recombination. The mutational spectra generated by Ty 1 transposition events may, due to their target specificity and gene regulatory capabilities, possess a higher frequency of adaptively favorable mutations than spectra resulting from other types of mutational processes. Laboratory strains contain between 25–35 elements, and in both these and industrial strains the insertions appear quite stable. In contrast, a wide variation in Ty number is seen in wild isolates, with a lower average number/genome. Factors which may determine Ty copy number in populations include transposition rates (dependent on Ty copy number and mating type), and stabilization of Ty elements in the genome as well as selection for and against Ty insertions in the genome. Although the average effect of Ty transpositions are deleterious, populations initiated with a single clone containing a single Ty element steadily accumulated Ty elements over 1,000 generations. Direct evidence that Ty transposition events can be selectively favored is provided by experiments in which populations containing large amounts of variability for Ty1 copy number were maintained for ∼100 generations in a homogeneous environment. At their termination, the frequency of clones containing 0 Ty elements had decreased to ∼0.0, and the populations had became dominated by a small number of clones containing >0 Ty elements. No such reduction in variability was observed in populations maintained in a structured environment, though changes in Ty number were observed. The implications of genetic (mating type and ploidy) changes and environmental fluctuations for the long-term persistence of Ty elements within the S. cerevisiae species group are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42799/1/10709_2004_Article_BF00133718.pd

The RNA Polymerase Dictates ORF1 Requirement and Timing of LINE and SINE Retrotransposition

Mobile elements comprise close to one half of the mass of the human genome. Only LINE-1 (L1), an autonomous non-Long Terminal Repeat (LTR) retrotransposon, and its non-autonomous partners—such as the retropseudogenes, SVA, and the SINE, Alu—are currently active human retroelements. Experimental evidence shows that Alu retrotransposition depends on L1 ORF2 protein, which has led to the presumption that LINEs and SINEs share the same basic insertional mechanism. Our data demonstrate clear differences in the time required to generate insertions between marked Alu and L1 elements. In our tissue culture system, the process of L1 insertion requires close to 48 hours. In contrast to the RNA pol II-driven L1, we find that pol III transcribed elements (Alu, the rodent SINE B2, and the 7SL, U6 and hY sequences) can generate inserts within 24 hours or less. Our analyses demonstrate that the observed retrotransposition timing does not dictate insertion rate and is independent of the type of reporter cassette utilized. The additional time requirement by L1 cannot be directly attributed to differences in transcription, transcript length, splicing processes, ORF2 protein production, or the ability of functional ORF2p to reach the nucleus. However, the insertion rate of a marked Alu transcript drastically drops when driven by an RNA pol II promoter (CMV) and the retrotransposition timing parallels that of L1. Furthermore, the “pol II Alu transcript” behaves like the processed pseudogenes in our retrotransposition assay, requiring supplementation with L1 ORF1p in addition to ORF2p. We postulate that the observed differences in retrotransposition kinetics of these elements are dictated by the type of RNA polymerase generating the transcript. We present a model that highlights the critical differences of LINE and SINE transcripts that likely define their retrotransposition timing

Functional Characteristics of a Highly Specific Integrase Encoded by an LTR-Retrotransposon

Background: The retroviral Integrase protein catalyzes the insertion of linear viral DNA into host cell DNA. Although different retroviruses have been shown to target distinctive chromosomal regions, few of them display a site-specific integration. ZAM, a retroelement from Drosophila melanogaster very similar in structure and replication cycle to mammalian retroviruses is highly site-specific. Indeed, ZAM copies target the genomic 59-CGCGCg-39 consensus-sequences. To enlighten the determinants of this high integration specificity, we investigated the functional properties of its integrase protein denoted ZAM-IN. Principal Findings: Here we show that ZAM-IN displays the property to nick DNA molecules in vitro. This endonuclease activity targets specific sequences that are present in a 388 bp fragment taken from the white locus and known to be a genomic ZAM integration site in vivo. Furthermore, ZAM-IN displays the unusual property to directly bind specific genomic DNA sequences. Two specific and independent sites are recognized within the 388 bp fragment of the white locus: the CGCGCg sequence and a closely apposed site different in sequence. Conclusion: This study strongly argues that the intrinsic properties of ZAM-IN, ie its binding properties and its endonuclease activity, play an important part in ZAM integration specificity. Its ability to select two binding sites and to nick the DNA molecule reminds the strategy used by some site-specific recombination enzymes and forms the basis for site-specifi

Localization of a bacterial group II intron-encoded protein in human cells

Group II introns are mobile retroelements that self-splice from precursor RNAs to form ribonucleoparticles (RNP), which can invade new specific genomic DNA sites. This specificity can be reprogrammed, for insertion into any desired DNA site, making these introns useful tools for bacterial genetic engineering. However, previous studies have suggested that these elements may function inefficiently in eukaryotes. We investigated the subcellular distribution, in cultured human cells, of the protein encoded by the group II intron RmInt1 (IEP) and several mutants. We created fusions with yellow fluorescent protein (YFP) and with a FLAG epitope. We found that the IEP was localized in the nucleus and nucleolus of the cells. Remarkably, it also accumulated at the periphery of the nuclear matrix. We were also able to identify spliced lariat intron RNA, which co-immunoprecipitated with the IEP, suggesting that functional RmInt1 RNPs can be assembled in cultured human cells.This work was supported by research grants CSD 2009–0006 from the Consolider-Ingenio, BIO2011-24401 and BIO2014-51953-P from the Spanish Ministerio de Economía y Competitividad all including ERDF (European Regional Development Funds). We thank Dr. Antonio Barrientos Durán for technical advice. MRC was supported by an FPI Ph.D grant. J.L.G.P´s laboratory is supported by CICE-FEDER-P09-CTS-4980, CICE-FEDER-P12-CTS-2256, Plan Nacional de I+D+I 2008–2011 and 2013–2016 (FIS-FEDER-PI11/01489 and FIS-FEDER-PI14/02152), PCIN-2014-115-ERA-NET NEURON II, the European Research Council (ERC-Consolidator ERC-STG-2012-233764) and by an International Early Career Scientist grant from the Howard Hughes Medical Institute (IECS-55007420).Peer Reviewe

A Single Heterochromatin Boundary Element Imposes Position-Independent Antisilencing Activity in Saccharomyces cerevisiae Minichromosomes

Chromatin boundary elements serve as cis-acting regulatory DNA signals required to protect genes from the effects of the neighboring heterochromatin. In the yeast genome, boundary elements act by establishing barriers for heterochromatin spreading and are sufficient to protect a reporter gene from transcriptional silencing when inserted between the silencer and the reporter gene. Here we dissected functional topography of silencers and boundary elements within circular minichromosomes in Saccharomyces cerevisiae. We found that both HML-E and HML-I silencers can efficiently repress the URA3 reporter on a multi-copy yeast minichromosome and we further showed that two distinct heterochromatin boundary elements STAR and TEF2-UASrpg are able to limit the heterochromatin spreading in circular minichromosomes. In surprising contrast to what had been observed in the yeast genome, we found that in minichromosomes the heterochromatin boundary elements inhibit silencing of the reporter gene even when just one boundary element is positioned at the distal end of the URA3 reporter or upstream of the silencer elements. Thus the STAR and TEF2-UASrpg boundary elements inhibit chromatin silencing through an antisilencing activity independently of their position or orientation in S. cerevisiae minichromosomes rather than by creating a position-specific barrier as seen in the genome. We propose that the circular DNA topology facilitates interactions between the boundary and silencing elements in the minichromosomes