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While CRISPR interference (CRISPRi) systems have been widely implemented in pooled lentiviral screening, there has been limited use with synthetic guide RNAs for the complex phenotypic readouts enabled by experiments in arrayed format. Here we describe a novel deactivated Cas9 fusion protein, dCas9-SALL1-SDS3, which produces greater target gene repression than first or second generation CRISPRi systems when used with chemically modified synthetic single guide RNAs (sgRNAs), while exhibiting high target specificity. We show that dCas9-SALL1-SDS3 interacts with key members of the histone deacetylase and Swi-independent three complexes, which are the endogenous functional effectors of SALL1 and SDS3. Synthetic sgRNAs can also be used with

The CRISPR-Cas9 system has been adapted for transcriptional activation (CRISPRa) and several second-generation CRISPRa systems (including VPR, SunTag, and SAM) have been developed to recruit different transcriptional activators to a deactivated Cas9, which is guided to a transcriptional start site via base complementarity with a target guide RNA. Multiple studies have shown the benefit of CRISPRa using plasmid or lentiviral expressed guide RNA, but the use of synthetic guide RNA has not been reported. Here we demonstrate the effective use of synthetic guide RNA for gene activation via CRISPRa. CRISPRa crRNA may be used with a canonical tracrRNA using the VPR or SunTag activation systems or with an extended tracrRNA containing an aptamer sequence for the SAM system. Transcriptional activation with synthetic crRNA:tracrRNA is comparable to activation achieved with expression vectors and combining several crRNA sequences targeting the same gene can enhance transcriptional activation. The use of synthetic crRNA is also ideal for simultaneous activation of multiple genes or use with dCas9-VPR mRNA when viral transduction is not feasible. Here, we perform a proof-of-principle arrayed screen using a CRISPRa crRNA library consisting of 153 cytokine receptor targets to identify regulators of IL-6 cytokine secretion. Together, these results demonstrate the suitability of synthetic CRISPRa guide RNA for high throughput, arrayed screening applications which allow for more complex phenotypic readouts to complement viability and drug resistance assays typically used in a pooled screening format.

MAD7 is an engineered class 2 type V-A CRISPR-Cas (Cas12a/Cpf1) system isolated from Eubacterium rectale. Analogous to Cas9, it is an RNA-guided nuclease with demonstrated gene editing activity in Escherichia coli and yeast cells. Here, we report that MAD7 is capable of generating indels and fluorescent gene tagging of endogenous genes in human HCT116 and U2OS cancer cell lines, respectively. In addition, MAD7 is highly proficient in generating indels, small DNA insertions (23 bases), and larger integrations ranging from 1 to 14 kb in size in mouse and rat embryos, resulting in live-born transgenic animals. Due to the different protospacer adjacent motif requirement, small-guide RNA, and highly efficient targeted gene disruption and insertions, MAD7 can expand the CRISPR toolbox for genome enginnering across different systems and model organisms.

The growth of the polypeptide chain occurs due to the fast and coordinated work of the ribosome and protein elongation factors, EF-Tu and EF-G. However, the exact contribution of each of these components in the overall balance of translation kinetics remains not fully understood. We created an in vitro translation system Escherichia coli replacing either elongation factor with heterologous thermophilic protein from Thermus thermophilus. The rates of the A-site binding and decoding reactions decreased an order of magnitude in the presence of thermophilic EF-Tu, indicating that the kinetics of aminoacyl-tRNA delivery depends on the properties of the elongation factor. On the contrary, thermophilic EF-G demonstrated the same translocation kinetics as a mesophilic protein. Effects of translocation inhibitors (spectinomycin, hygromycin B, viomycin and streptomycin) were also similar for both proteins. Thus, the process of translocation largely relies on the interaction of tRNAs and the ribosome and can be efficiently catalysed by thermophilic EF-G even at suboptimal temperatures.

Ribosome biogenesis is a highly coordinated and complex process that requires numerous assembly factors that ensure prompt and flawless maturation of ribosomal subunits. Despite the increasing amount of data collected, the exact role of most assembly factors and mechanistic details of their operation remain unclear, mainly due to the shortage of high-resolution structural information. Here, using cryo-electron microscopy, we characterized 30S ribosomal particles isolated from an Escherichia&nbsp, coli strain with a deleted gene for the RbfA factor. The cryo-EM maps for pre-30S subunits were divided into six classes corresponding to consecutive assembly intermediates: from the particles with a completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and partially distorted helix 44. The structures of two predominant 30S intermediates belonging to most populated classes obtained at 2.7 Å resolutions indicate that RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including folding of the head, and positioning of helix 44 in the decoding center at a later stage. Additionally, it was shown that the formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. An update to the model of factor-dependent 30S maturation is proposed, suggesting that RfbA is involved in most of the subunit assembly process.

Today’s trend is the growth of information security incidents. Confirmation of this is the data of the company InfoWatch, according to which the number of leaks of confidential information in the first half of 2017 has increased by 10% as compared to the same period of 2016, and equals to 925 cases. However, 53% out of these 925 cases of diversion were sold by company employees, and 1.7% – by potential insiders. In the modern world, an insider is a very common concept. It is applicable in different spheres of economic activity. In a general sense, an insider is a natural or legal person who, due to his or her position, has access to valuable (mainly, of course, from an economic point of view) information. Valuable information is also called insider information. The article is devoted to the consideration of video capture systems that can help prevent leakage of information from personal computers in the enterprise. The proposed scheme of expert evaluation of video capture allows you to determine the system based on the selected criteria and specified weight coefficients, and lets the user make the best choice in the decision-making process of a specific problem.

Categories ‘attack’, ‘intrusion’ and ‘incident’ of information security are defined. The types of intrusions into the information system are revealed, and their brief analysis is given. The proposed model of intrusion into the information system will allow to increase its efficiency at almost all stages of the information security system life cycle. The use of the proposed model is associated with the solution of specific practical problems in the field of information security, including the definition of vulnerabilities of the information system. The latter, in turn, is necessary to determine the elements of the protection system. For example, at the design stage of the information security system, when choosing software protection you need to take into account the location of the intruder relative to the attacked object. When working with functioning systems of information protection, i.e. at the solution of questions of modernization or optimization, changes in the system of information security are resolved in accordance with statistical data for the intrusion into the information system with available results of information security incidents, with the forecast data. Thus, the proposed model of intrusion into the information system is one of the external conditions when working with the information system of the organization (enterprise) may well determine (set) the level of risk of information security of the enterprise.

The use of information technology in all spheres of activity raises the problem of hygienic regulation of information loads for the population, especially children. The authors describe the negative effects of information on children and adolescents. Due to this fact, there is a need to create secure information environment. It is necessary to list some principles of information hygiene: complexity, focus, socio-political activity, science, accessibility, integrity, consistency, qualitative and quantitative approach in data analysis, differentiated and individual approach to the child, continuity of protection, ease of use of protective methods and tools, reasonable sufficiency, flexibility of management and application, openness of algorithms and protection mechanisms, validity of access, personal responsibility, etc. Thus, the development of the information society involves developing information hygiene to prevent the negative impact of information load from different sources on the health of the population, especially children. It is necessary to calculate the individual risks of different types of information and to predict their consequences for the health of adolescents, followed by the development of a program of preventive and recreational work with them. To this end, Russia has the scientific potential and modern technologies in the field of hygiene, protection and promotion of the health of children, adolescents and young people.

With the introduction of Federal Law No. 187 [1], methodological issues of ensuring information security of processes, systems, and technologies were updated. The introduced regulatory documents regulate these issues without taking into account a systematic approach. In addition, the assessment of information security (IS) of the subject of critical information infrastructure (SCII) does not take into account infrastructure destructive, the appearance of which is possible due to inter-object systems of relationships and interactions at the level of the subject of CII. SCII is a complex multi-component dynamic system. In a number of works, cognitive modeling and a scenario approach were used to justify and implement a comprehensive assessment of information security. To ensure its safety, it is necessary to make management decisions. For the development of the information security management system, it is proposed to use proactive modeling. As one of the indicators of the effectiveness of proactive management at the level of ensuring the safety of SCII, we can consider the coefficient of structural functionality of the SCII. To evaluate this indicator, we propose a developed model and a methodology for working with it. Expected indicators of the competitive advantages of the using of proactive security management of the SCII: stabilization of the processes of ensuring the security of the SCII at all stages of the life cycle, reduction of the costs of ensuring the security of the components of the SCII, including in the dynamic model.

The security of a subject of critical information infrastructure (CII) is one of the key issues of its life support. The current approach (legal and regulatory) regulates solutions to this issue without taking into account the influence of the violator, which can have a destructive effect on the subject of CII. This, in our opinion, leads to significant errors in the analysis of information security of the CII subject, therefore, reduces the effectiveness of declared information security tools for CII objects. The purpose of this work is to develop a model of an information security violator taking into account the parameter “potential of the violator”. At the same time, the activity of the violator is considered in the space of its implementation of destructive effects on the objects of CII. The proposed model for assessing the capabilities of the violator to implement destructive effects on the subject of critical information infrastructure is implemented in the module “categorizing the attacker” of the cognitive model “Assessment of information security of the subject of CII”. The proposed model allows us to assess the level of information security under destructive influences and to predict changes in malicious actions on CII objects in dynamics.

Purpose: The purpose of the work is the use of “smart” solutions when developing a model for protecting the information of a subject of CII taking into account the destructive impact on the subject.

Background: Ribosome biogenesis is a complicated multi-stage process. In the cell, 30S ribosomal subunit assembly is fast and efficient, proceeding with the help of numerous assembly protein factors. The exact role of most assembly factors and mechanistic details of their operation remain unclear. The combination of genetic modification with cryo-EM analysis is widely used to identify the role of protein factors in assisting specific steps of the ribosome assembly process. The strain with knockout of a single assembly factor gene accumulates immature ribosomal particles which structural characterization reveals the information about the reactions catalyzed by the corresponding factor. Methods: We isolated the immature 30S subunits (pre-30S subunits) from the Escherichia coli strain lacking the rbfA gene (ΔrbfA) and characterized them by cryo-electron microscopy (cryo-EM). Results: Deletion of the assembly factor RbfA caused a substantial distortion of the structure of an important central pseudoknot which connects three major domains of 30S subunit and is necessary for ribosome stability. It was shown that the relative order of the assembly of the 3′ head domain and the docking of the functionally important helix 44 depends on the presence of RbfA. The formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. The cryo-EM maps for pre-30S subunits were divided into the classes corresponding to consecutive assembly intermediates: from the particles with completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and with partially distorted helix 44. Cryo-EM analysis of ΔrbfA 30S particles revealing the accumulation of two predominant classes of early and late intermediates (obtained at 2.7 Å resolutions) allowed us to suggest that RbfA participate in two stages of the 30S subunit assembly and is deeper involved in the maturation process than previously thought. Conclusion: In summary, RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including the folding of the head, and positioning of helix 44 in the decoding center at a later stage. An update to the model of factor-dependent 30S maturation was proposed, suggesting that RfbA is involved in most of the subunit assembly process.

During host colonization, bacteria use the alarmones (p)ppGpp to reshape their proteome by acting pleiotropically on DNA, RNA, and protein synthesis. Here, we elucidate how the initiating ribosome senses the cellular pool of guanosine nucleotides and regulates the progression towards protein synthesis. Our results show that the affinity of guanosine triphosphate (GTP) and the inhibitory concentration of ppGpp for the 30S-bound initiation factor IF2 vary depending on the programmed mRNA. The TufA mRNA enhanced GTP affinity for 30S complexes, resulting in improved ppGpp tolerance and allowing efficient protein synthesis. Conversely, the InfA mRNA allowed ppGpp to compete with GTP for IF2, thus stalling 30S complexes. Structural modeling and biochemical analysis of the TufA mRNA unveiled a structured enhancer of translation initiation (SETI) composed of two consecutive hairpins proximal to the translation initiation region (TIR) that largely account for ppGpp tolerance under physiological concentrations of guanosine nucleotides. Furthermore, our results show that the mechanism enhancing ppGpp tolerance is not restricted to the TufA mRNA, as similar ppGpp tolerance was found for the SETI-containing Rnr mRNA. Finally, we show that IF2 can use pppGpp to promote the formation of 30S initiation complexes (ICs), albeit requiring higher factor concentration and resulting in slower transitions to translation elongation. Altogether, our data unveil a novel regulatory mechanism at the onset of protein synthesis that tolerates physiological concentrations of ppGpp and that bacteria can exploit to modulate their proteome as a function of the nutritional shift happening during stringent response and infection., During host colonization, the alarmones ppGpp and pppGpp reshape the bacterial proteome by acting on DNA, RNA, and protein synthesis. This study shows that inhibition of translation by ppGpp involves prevention of 30S initiation complex formation by ppGpp-bound IF2, with the extent of ppGpp tolerance depending on the specific mRNA.

Ivan Bunin occupies a unique place in the context of Russian literature. The following article demonstrates the relevance of Juri Lotman’s work on defining semiotic artistic space by examining Bunin’s modeling of the world and his construction of artistic space in his prose works. Special attention is paid to the semiosphere, its central mechanisms, and their realization in several of Bunin’s works, and especially the short story entitled “Horror Story”., La place occupée par Ivan Bunin dans la littérature russe est unique. Le présent article illustre la pertinence du travail de Juri Lotman sur la définition d’espace sémiotique artistique pour comprendre la modélisation du monde chez Bunin et la construction de l’espace artistique dans sa prose. Une attention particulière est portée à la sémiosphère, à ses mécanismes centraux et à leur réalisation dans l’oeuvre de Bunin, et tout particulièrement à la nouvelle intitulée “Histoire d’horreur”.

Modern monitoring and accounting tools allow to accumulate a significant amount of thematic information, which can be a good basis for supporting management decisions on the development of urban areas. Therefore, this paper proposes a number of methods for a comprehensive evaluation and work with information about residential real estate. Modern approaches to work with data on the real estate market are considered. However, an appropriate information infrastructure is needed to obtain a holistic view of the composition and status of residential real estate. The paper describes the developed system for spatial monitoring of real estate objects, as well as the tools included in it for presentation geospatial data on residential objects (at the level of buildings and apartments) and assessing their value based on comparative approach. It is proposed to use the “box-and-whiskers” method to determine price spike for objects in the process of using the comparative approach.

The CRISPR-Cas9 system has been utilized for large-scale, loss-of-function screens mainly using lentiviral pooled formats and cell-survival phenotypic assays. Screening in an arrayed format expands the types of phenotypic readouts that can be used to now include high-content, morphology-based assays, and with the recent availability of synthetic crRNA libraries, new studies are emerging. Here, we use a cell cycle reporter cell line to perform an arrayed, synthetic crRNA:tracrRNA screen targeting 169 genes (>600 crRNAs) and used high content analysis (HCA) to identify genes that regulate the cell cycle. Seven parameters were used to classify cells into cell cycle categories and multiple parameters were combined using a new analysis technique to identify hits. Comprehensive hit follow-up experiments included target gene expression analysis, confirmation of DNA insertions/deletions, and validation with orthogonal reagents. Our results show that most hits had three or more independent crRNAs per gene that demonstrated a phenotype with consistent individual parameters, indicating that our screen produced high-confidence hits with low off-target effects and allowed us to identify hits with more subtle phenotypes. The results of our screen demonstrate the power of using arrayed, synthetic crRNAs for functional phenotypic screening using multiparameter HCA assays.

Background: About 50% of antibiotics used in the therapy of infectious diseases target bacterial 70S ribosomes. High resolution X-ray crystallographic studies allow us for determination of position of drug on the ribosome, but to elucidate the detailed molecular mechanism of inhibition it is necessary to study the dynamics of partial reactions of protein biosynthesis. Majority of high resolution structures were obtained on ribosomes from thermophilic bacteria T. thermophilus, whereas most of the functional studies were performed on reconstituted in vitro translation system from mesophilic organism E. coli. Despite of high homology among bacterial ribosomes, in many cases particular contacts observed are specific to thermophilic organism and is not allowing us to generalize the molecular mechanism of inhibition. Methods: Functional ribosomal pre-translocation complexes containing deacylated tRNAfMet in the P site and fMetPhe-tRNAPhe or fMetVal-tRNAVal in the A site were incubated with specific inhibitors: spectinomycin, amicoumacin, dirithromycin. Functional and structural studies were performed by using pre-steady state stopped-flow fluorescent spectroscopy and time-resolved cryo-electron microscopy. Kinetic studies of partial reactions of elongation were performed with thermophilic elongation factors and mesophilic reconstituted translation system. Results: Combination of structural data and pre-steady state kinetics reveals the details of molecular mechanism of inhibition of EF-G catalysed translocation and shows the intermediate conformations of ribosome-tRNA complexes during forward translocation. Heterologous translation system with substituted thermophilic elongation factors allows for differential studies of elongation cycle. Conclusion: Time-resolved high resolution cryo-electron microscopy is a method of choice for structural characterization of active complexes in physiological conditions in the process of functioning. Reconstituted in vitro translation system from E. coli can be used both for structural and functional studies, allowing merging of two types of data for extensive characterization of bacterial protein synthesis apparatus.

During host colonization, bacteria use the alarmone (p)ppGpp to reshape its proteome by acting pleiotropically on RNA and protein synthesis. Here, we elucidate how the translation Initiation Factor 2 (IF2) senses the cellular ppGpp to GTP ratio and regulates the progression towards protein synthesis. Our results show that the affinity of GTP and the inhibitory concentration of ppGpp for 30S-bound IF2 vary depending on the programmed mRNA. Highly translated mRNAs enhanced GTP affinity for 30S complexes, resulting in fast transitions to elongation of protein synthesis. Less demanded mRNAs allowed ppGpp to compete with GTP for IF2, stalling 30S complexes until exchange of the mRNA enhances the affinity for GTP. Altogether, our data unveil a novel regulatory mechanism at the onset of protein synthesis that tolerates physiological concentrations of ppGpp, and that bacteria can exploit to modulate its proteome as a function of the nutritional shift happening during infection.

While the CRISPR-Cas9 system from S. pyogenes is a powerful genome engineering tool, additional programmed nucleases would enable added flexibility in targeting space and multiplexing. Here, we characterized a CRISPR-Cas9 system from L. gasseri and found that it has modest activity in a cell-free lysate assay but no activity in mammalian cells even when altering promoter, position of tag sequences and NLS, and length of crRNA:tracrRNA. In the lysate assay we tested over 400 sequential crRNA target sequences and found that the Lga Cas9 PAM is NNGA/NDRA, different than NTAA predicted from the native bacterial host. In addition, we found multiple instances of consecutive crRNA target sites, indicating flexibility in either PAM sequence or distance from the crRNA target site. This work highlights the need for characterization of new CRISPR systems and highlights the non-triviality of porting them into eukaryotes as gene editing tools.

During amino acid starvation the Escherichia coli stringent response factor RelA recognizes deacylated tRNA in the ribosomal A-site. This interaction activates RelA-mediated synthesis of alarmone nucleotides pppGpp and ppGpp, collectively referred to as (p)ppGpp. These two alarmones are synthesized by addition of a pyrophosphate moiety to the 3′ position of the abundant cellular nucleotide GTP and less abundant nucleotide GDP, respectively. Using untagged native RelA we show that allosteric activation of RelA by pppGpp increases the efficiency of GDP conversion to achieve the maximum rate of (p)ppGpp production. Using a panel of ribosomal RNA mutants, we show that the A-site finger structural element of 23S rRNA helix 38 is crucial for RelA binding to the ribosome and consequent activation, and deletion of the element severely compromises (p)ppGpp accumulation in E. coli upon amino acid starvation. Through binding assays and enzymology, we show that E. coli RelA does not form a stable complex with, and is not activated by, deacylated tRNA off the ribosome. This indicates that in the cell, RelA first binds the empty A-site and then recruits tRNA rather than first binding tRNA and then binding the ribosome.

Cas9 protein of the Type II CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated)1 bacterial adaptive immune system emerged recently as a promising tool for genom...

Functional gene analysis studies have been empowered by development of CRISPR-Cas9 gene knockout tools, however the CRISPR-Cas9 system has also been adapted for inhibition or activation of gene transcription. A nuclease-deactivated Cas9 (dCas9) can be fused to various effector domains to produce an RNA-guided transcription factor for either inhibition (CRISPRi) or activation (CRISPRa) of target genes. For overexpression studies, CRISPRa holds significant advantages over traditional vector-based gene expression, because genes are upregulated from their native promoter and endogenous genomic context. The majority of CRISPRa research performed to date has utilized single guide RNA (sgRNA) expressed from a DNA vector, primarily in the context of pooled lentiviral screening approaches. Here we describe the development of CRISPRa synthetic guide RNAs for the use in arrayed screening, so that we combine this next-generation transcriptional activation method with the ability to support more complex assays in a one-gene-per well format. Considerations for arrayed activation screens will be shown. The combination of gain-of-function from CRISPRa with loss-of-function using RNAi or canonical CRISPR-Cas9 for gene knockout allows for robust characterization of gene mechanisms and pathways. Citation Format: Annaleen Vermeulen, Zaklina Strezoska, Sarah M. Dickerson, Maren M. Gross, Eldon T. Chou, Elena Maksimova, Matthew R. Perkett, Shawn McClelland, Anja V. Smith. Development of synthetic guide RNA libraries for CRISPR-mediated transcriptional activation screening for gain-of-function studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2761.

Ultrashort monolithic columns (disks) were thoroughly studied as efficient stationary phases for precipitation-dissolution chromatography of synthetic polymers. Gradient elution mode was applied in all chromatographic runs. The mixtures of different flexible chain homopolymers, such as polystyrenes, poly(methyl methacrylates), and poly(tert-butylmethacrylates) were separated according to their molecular weights on both commercial poly(styrene-co-divinylbenzene) disks (12 id × 3 mm and 5 × 5 mm) and lab-made monolithic columns (4.6 id × 50 mm) filled with supports of different hydrophobicity. The experimental conditions were optimized to reach fast and highly efficient separation. It was observed that, similar to the separation of monoliths of other classes of (macro)molecules (proteins, DNA, oligonucleotides), the length of column did not affect the peak resolution. A comparison of the retention properties of the poly(styrene-co-divinylbenzene) disk-shaped monoliths with those based on poly(lauryl methacrylate-co-ethylene dimethacrylate), poly(butyl methacrylate-co-ethylene dimethacrylate), and poly(glycidyl methacrylate-co-ethylene dimethacrylate) supports demonstrated the obvious effect of surface chemistry on the resolution factor. Additionally, the results of the discussed chromatographic mode on the fast determination of the molecular weights of homopolymers used in this study were compared to those established by SEC on columns packed with sorbent beads of a similar nature to the monoliths.

The role of proinflammatory cytokines in the response to acute stressor exposure has received recent attention. Exposure to a single session of inescapable shock (IS) induces peripheral and central proinflammatory cytokines. Other stressors also increase expression of proinflammatory cytokine mRNA and/or protein in various tissues. However, the induction of central and peripheral proinflammatory cytokines by stressors remains controversial and the pattern of cytokine induction is not consistent across stressors. The present experiments sought to examine the pattern of the proinflammatory cytokine response to a stressor known to cause elevations of IL-1beta protein. mRNA expression for three proinflammatory cytokines, IL-1beta, TNF-alpha and IL-6, and IL-1beta protein was examined after IS. IS increases IL-1beta mRNA and/or protein in a variety of tissues, including hypothalamus, hippocampus, pituitary and spleen. Furthermore, IS concomitantly alters IL-1beta mRNA and protein in hypothalamus and spleen, while the IL-1beta mRNA increase in pituitary lags behind the increase of IL-1beta protein. Interestingly, IL-1beta mRNA is elevated in hippocampus 4 h after IS, but an increase of IL-1beta protein in hippocampus is not detected. Expression of TNF-alpha and IL-6 mRNA do not increase in response to IS. Indeed, TNF-alpha mRNA expression decreases in cortex, pituitary and liver immediately after IS. These findings suggest that alterations of proinflammatory cytokine expression by stressors, and IS in particular, are region- and cytokine-specific.

CHO cells expressing the human insulin receptors (IR) were used to evaluate the effect of the potent farnesyltransferase inhibitor, manumycin, on insulin antiapoptotic function. Cell treatment with manumycin blocked insulin's ability to suppress pro-apoptotic caspase-3 activity which led to time-dependent proteolytic cleavage of two nuclear target proteins. The Raf-1/MEK/ERK cascade and the serine/threonine protein kinase Akt are two survival pathways that may be activated in response to insulin. We tested the hypothesis that inhibition of farnesylated Ras was causally related to manumycin-induced apoptosis and showed that the response to manumycin was found to be independent of K-Ras function because membrane association and activation of endogenous K-Ras proteins in terms of GTP loading and ERK activation were unabated following treatment with manumycin. Moreover, blocking p21Ras/Raf-1/MEK/ERK cascade by the expression of a transdominant inhibitory mSOS1 mutant in CHO-IR cells kept cells sensitive to the antiapoptotic action of insulin. Insulin-dependent activation of Akt was blocked by 4 h treatment with manumycin (P < 0.01), a kinetic too rapid to be explained by Ras inhibition. This study suggests that the depletion of short-lived farnesylated proteins by manumycin suppresses the antiapoptotic action of insulin at least in part by disrupting Akt activation but not that of the K-Ras/Raf-1/ERK-dependent cascade.

Ultrashort monolithic columns (disks) were thoroughly studied as efficient stationary phases for precipitation-dissolution chromatography of synthetic polymers. Gradient elution mode was applied in all chromatographic runs. The mixtures of different flexible chain homopolymers, such as polystyrenes, poly(methyl methacrylates), and poly(tert-butylmethacrylates) were separated according to their molecular weights on both commercial poly(styrene-co-divinylbenzene) disks (12 id × 3 mm and 5 × 5 mm) and lab-made monolithic columns (4.6 id × 50 mm) filled with supports of different hydrophobicity. The experimental conditions were optimized to reach fast and highly efficient separation. It was observed that, similar to the separation of monoliths of other classes of (macro)molecules (proteins, DNA, oligonucleotides), the length of column did not affect the peak resolution. A comparison of the retention properties of the poly(styrene-co-divinylbenzene) disk-shaped monoliths with those based on poly(lauryl methacrylate-co-ethylene dimethacrylate), poly(butyl methacrylate-co-ethylene dimethacrylate), and poly(glycidyl methacrylate-co-ethylene dimethacrylate) supports demonstrated the obvious effect of surface chemistry on the resolution factor. Additionally, the results of the discussed chromatographic mode on the fast determination of the molecular weights of homopolymers used in this study were compared to those established by SEC on columns packed with sorbent beads of a similar nature to the monoliths.