Оценка конъюнктуры рынка металлопродукции

У статті розглянуті проблеми стратегічного розвитку й конкурентоспроможності вітчизняних підприємств на світовому ринку металопродукції. Запропоновано науково-теоретичне визначення підходів до оцінки стратегічних альтернатив конкурентоспроможності великих металургійних підприємств. Ключові слова: металургійні підприємства, стратегія, конкурентоспроможність.В статье рассмотрены проблемы стратегического развития и конкурентоспособности отечественных предприятий на мировом рынке металлопродукции. Предложено научно-теоретическое определение подходов к оценке стратегических альтернатив конкурентоспособности крупных металлургических предприятий. Ключевые слова: металлургические предприятия, стратегия, конкурентоспособность.This article is devoted to problems of strategic development and competitiveness of domestic enterprises are considered in the world market. Proposed scientific theoretical definition of approaches to evaluation of strategic alternatives to the competitiveness of large metallurgical enterprises. Key words: metallurgical industry, strategy, competitiveness

Suppression of an absolute defect in Type IV pilus biogenesis by loss-of-function mutations in pilT, a twitching motility gene in Neisseria gonorrhoeae

Type IV pili of Neisseria gonorrhoeae, the Gram-negative etiologic agent of gonorrhea, facilitate colonization of the human host. Gonococcal PilT, a protein belonging to a large family of molecules sharing a highly conserved nucleotide binding domain motif, has been shown to be dispensable for organelle biogenesis but essential for twitching motility and competence for genetic transformation. Here, we show that the defect in pilus biogenesis resulting from mutations in the pilC gene, encoding a putative pilus-associated adhesin for human tissue, can be suppressed by the absence of functional PilT. These data conclusively demonstrate that PilT influences the Type IV pilus biogenesis pathway and strongly suggest that organelle expression is a dynamic process. In addition, these findings imply that PilT antagonizes the process of organelle biogenesis and provide the basis for a model for how the counteractive roles of PilT and PilC might relate mechanistically to the phenomenon of twitching motility

Neisseria gonorrhoeae PilV, a type IV pilus-associated protein essential to human epithelial cell adherence

Type IV pili (Tfp) of Neisseria gonorrhoeae, the Gram-negative etiologic agent of gonorrhea, facilitate colonization of the human host. Tfp are assumed to play a key role in the initial adherence to human epithelial cells by virtue of the associated adhesin protein PilC. To examine the structural and functional basis for adherence in more detail, we identified potential genes encoding polypeptides sharing structural similarities to PilE (the Tfp subunit) within the N. gonorrhoeae genome sequence database. We show here that a fiber subunit-like protein, termed PilV, is essential to organelle-associated adherence but dispensable for Tfp biogenesis and other pilus-related phenotypes, including autoagglutination, competence for natural transformation, and twitching motility. The adherence defect in pilV mutants cannot be attributed to reduced levels of piliation, defects in fiber anchoring to the bacterial cell surface, or to unstable pilus expression related to organelle retraction. PilV is expressed at low levels relative to PilE and copurifies with Tfp fibers in a PilC-dependent fashion. Purified Tfp from pilV mutants contain PilC adhesin at reduced levels. Taken together, these data support a model in which PilV functions in adherence by promoting the functional display of PilC in the context of the pilus fiber

Unique properties of the chicken TLR4/MD-2 complex: selective lipopolysaccharide activation of the MyD88-dependent pathway.

Abstract During evolution, mammals have evolved a powerful innate immune response to LPS. Chickens are much more resistant to LPS-induced septic shock. Herein we report that chickens sense LPS via orthologs of mammalian TLR4 and myeloid differentiation protein-2 (MD-2) rather than the previously implicated chicken TLR2 isoform type 2 (chTLR2t2) receptor. Cloning and expression of recombinant chTLR4 and chMD-2 in HeLa 57A cells activated NF-κB at concentrations of LPS as low as 100 pg/ml. Differential pairing of chicken and mammalian TLR4 and MD-2 indicated that the protein interaction was species-specific in contrast to the formation of functional human and murine chimeric complexes. The chicken LPS receptor responded to a wide variety of LPS derivatives and to the synthetic lipid A compounds 406 and 506. The LPS specificity resembled the functionality of the murine rather than the human TLR4/MD-2 complex. Polymorphism in chTLR4 (Tyr383His and Gln611Arg) did not influence the LPS response. Interestingly, LPS consistently failed to activate the MyD88-independent induction of IFN-β in chicken cells, in contrast to the TLR3 agonist poly(I:C) that yielded a potent IFN-β response. These results suggest that chicken lack a functional LPS-specific TRAM-TRIF (TRIF-related adapter molecule/TIR-domain-containing adapter-inducing IFN-β) signaling pathway, which may explain their aberrant response to LPS compared with the mammalian species.</jats:p

The FlgS/FlgR two-component signal transduction system regulates the fla regulon in Campylobacter jejuni

The human pathogen Campylobacter jejuni is a highly motile organism that carries a flagellum on each pole. The flagellar motility is regarded as an important trait in C. jejuni colonization of the intestinal tract, however, the knowledge of the regulation of this important colonization factor is rudimentary. We demonstrate by phosphorylation assays that the sensor FlgS and the response regulator FlgR form a two-component system that is on the top of the Campylobacter flagellum hierarchy. Phosphorylated FlgR is needed to activate RpoN-dependent genes of which the products form the hook-basal body filament complex. By real-time reverse transcriptase-PCR we identified that FlgS, FlgR, RpoN, and FliA belong to the early flagellar genes and are regulated by 70. FliD and the putative anti--factor FlgM are regulated by a 54- and 28-dependent promoters. Activation of the fla regulon is growth phase-dependent, a 100-fold rpoN mRNA reduction is seen in the early stationary phase compared with the early logarithmic phase. Whereas flaB transcription decreases, flaA transcription increases in early stationary phase. Our data show that the C. jejuni flagellar hierarchy largely differs from that of other bacteria. Phenotypical analysis revealed that unflagellated C. jejuni mutants grow three times faster in broth medium compared with wild-type bacteria. In vivo the C. jejuni flagella are needed to pass the gastrointestinal tract of chickens, but not to colonize the ceaca of the chicken

The FlgS/FlgR two-component signal transduction system regulates the fla regulon in Campylobacter jejuni

The human pathogen Campylobacter jejuni is a highly motile organism that carries a flagellum on each pole. The flagellar motility is regarded as an important trait in C. jejuni colonization of the intestinal tract, however, the knowledge of the regulation of this important colonization factor is rudimentary. We demonstrate by phosphorylation assays that the sensor FlgS and the response regulator FlgR form a two-component system that is on the top of the Campylobacter flagellum hierarchy. Phosphorylated FlgR is needed to activate RpoN-dependent genes of which the products form the hook-basal body filament complex. By real-time reverse transcriptase-PCR we identified that FlgS, FlgR, RpoN, and FliA belong to the early flagellar genes and are regulated by 70. FliD and the putative anti--factor FlgM are regulated by a 54- and 28-dependent promoters. Activation of the fla regulon is growth phase-dependent, a 100-fold rpoN mRNA reduction is seen in the early stationary phase compared with the early logarithmic phase. Whereas flaB transcription decreases, flaA transcription increases in early stationary phase. Our data show that the C. jejuni flagellar hierarchy largely differs from that of other bacteria. Phenotypical analysis revealed that unflagellated C. jejuni mutants grow three times faster in broth medium compared with wild-type bacteria. In vivo the C. jejuni flagella are needed to pass the gastrointestinal tract of chickens, but not to colonize the ceaca of the chicken

Do competition and selective herbivory cause replacement of Phragmites australis by tall forbs?

We investigated the role of biotic factors in determining abundance of the low marsh species Phragmites australis and the high marsh species Epilobium hirsutum. In a 2-year field experiment, at a position where Phragmites and Epilobium co-occurred, responses of both species to each other's removal were measured. In the second year, we also tested if larvae of Archanara geminipuncta, which feed exclusively on Phragmites shoots, affect the competitive ability of Phragmites relative to Epilobium. For both species, removal of aboveground material by clipping did not enhance shoot size or decrease variability in shoot size of the removed species itself. Surprisingly however, shoot numbers of both species increased after removal of the other, which demonstrates that there was a mutual inhibition of each other's abundance. Comparing the responses of Archanara-infested and non-infested Phragmites shoots revealed no increased competitive suppression by Epilobium due to selective herbivory. Ins These results contradict the common assumption that biotic factors constrain a species upper limit along flooding gradients. Instead, our result suggest that different biotic interactions may counteract each other and thus slow down replacement by successive species. [KEYWORDS: Clonal growth; Diversity; Insect–plant interaction; Removal experiment;]