Alternative Modes Of Regulation Research Articles

The antimicrobial peptide chensinin-1b alleviates the inflammatory response by targeting the TLR4/NF-κB signaling pathway and inhibits Pseudomonas aeruginosa infection and LPS-mediated sepsis

Excessive inflammatory responses are a major contributor to the high mortality associated with sepsis, a prevalent global complication. Therefore, the potential therapeutic strategy for sepsis involves targeting macrophages and reducing proinflammatory cytokine release. Chensinin-1b, an analog of the natural antimicrobial peptide derived from Rana chensinensis skin secretion, exhibits broad-spectrum antibacterial activity and adopts a random coil conformation in both PBS and membrane solution. By efficiently neutralizing LPS, chensinin-1b holds promise in alleviating LPS-induced inflammatory responses. In this study, we established a mouse septic shock model by exposing mice to multiple-drug-resistant Pseudomonas aeruginosa, as well as an endotoxin-mediated sepsis model induced by LPS. Administering chensinin-1b significantly prolonged the survival of the experimental mice, concurrently mitigating inflammatory responses and reducing organ damage. Additionally, we investigated the anti-inflammatory mechanism of chensinin-1b using a constructed LPS-induced mouse macrophage RAW264.7 inflammatory model. Our findings demonstrated that chensinin-1b effectively mitigated the excessive activation of the TLR4/NF-κB signaling pathway by directly neutralizing extracellular LPS, thus ameliorating the inflammatory response. Moreover, upon blocking the TLR4 signaling pathway, chensinin-1b further reduced the release of proinflammatory cytokines induced by LPS, indicating alternative modes of regulation. Notably, chensinin-1b rapidly entered RAW264.7 cells within 30 min via endocytosis, diffusing into the cytoplasm while retaining its anti-inflammatory properties intracellularly. Although further investigations are warranted to comprehensively elucidate the intracellular anti-inflammatory mechanism of chensinin-1b, our findings substantiate its possession of anti-inflammatory properties both intracellularly and extracellularly. Thus, chensinin-1b emerges as a promising candidate for mitigating excessive inflammatory responses associated with sepsis.

Platforms as regulators

Abstract The proposition that certain digital platforms act as ‘regulators’ within their own business models is a key pillar of the European Commission report on Competition Policy for the Digital Era, and the basis upon which its authors build a wide-ranging duty for dominant platforms to secure competition that is ‘fair, unbiased and pro-users’. This article seeks to shed light on this novel contention, exploring its meaning and the implications for platform operators. It considers the rationale provided within the report and compares the approach with established Article 102 TFEU case law, specifically the ‘special responsibility’ doctrine. Consideration is further given to whether the platforms-as-regulators notion aligns with alternative modes of regulation within the digital sphere. The aim is to explore whether this approach is coherent, and actually useful, as a means by which to frame and direct future enforcement against digital platforms.

Platforms as Regulators

The proposition that certain digital platforms act as ‘regulators’ within their own business models is a key pillar of the European Commission report on Competition Policy for the Digital Era, and the basis upon which its authors build a wide-ranging duty for dominant platforms to secure competition that is ‘fair, unbiased and pro-users’. This article seeks to shed light on this novel contention, exploring its meaning and the implications for platform operators. It considers the rationale provided within the report, and compares the approach with established Art.102 TFEU case-law, specifically the ‘special responsibility’ doctrine. Consideration is also given to whether the platforms-as-regulators notion aligns with alternative modes of regulation within the digital sphere. The aim is to explore whether this approach is coherent, and actually useful, as a means by which to frame and direct future enforcement against digital platforms.

English

The properties of xylanase purified from Fusarium heterosporum that was grown in barley-brewing residue under solid-state fermentation and the effects of thiol compounds on the reactivation of the metal ion-inhibited xylanase were investigated. Xylanase was purified to homogeneity by ion exchange chromatography, and its molecular mass was estimated to be 19.5 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH for the xylanase was 5.0, and it was stable in acidic pH (4.5 to 5.5), where it retained more than 87% of its activity after 24 h. The optimum temperature was 50°C, and it had a half-life of 53 min at 45°C. The apparent Km and Vmax values for the xylanase were 5.63 mg/ml and 800 µmol/mg/min, respectively. Ba2+, Ca2+, Mg2+ and the thiol compounds β-mercaptoethanol and dithiothreitol (DTT) enhanced xylanase activity, while Hg2+, Pb2+ and Zn2+ strongly inhibited enzyme activity. Furthermore, this xylanase had an alternative mode of regulation in the presence of thiol compounds because the enzyme was able to recover its catalytic activity after inhibition by heavy metal ions.   Key words: Hemicellulase, fungus, solid-state fermentation, barley brewing residue, thiol compounds.

Calreticulin in rainbow trout: A limited response to Endoplasmic Reticulum (ER) stress

Calreticulin (CRT) is a resident protein of the endoplasmic reticulum where it serves as a calcium modulator and chaperone to newly synthesized glycoproteins. In mammals, CRT is a structurally conserved 46 kDa protein that demonstrates anomalous migration at 60 kDa on SDS polyacrylamide gels and can be up-regulated by A23187 and thapsigargin due to the endoplasmic reticulum stress elements (ERSE) in the promoter region of its gene. CRT has numerous proposed functions and has been localized to the surface of PHA-stimulated T lymphocytes. CRT has been identified in mammals, plants and more recently from rainbow trout. Here, we report the cloning of the CRT proximal promoter from rainbow trout which includes elements typical of genes transcribed by RNA polymerase II including a TATA box, an Sp1 binding site, CCAAT boxes and the conservation of promoter stress elements (ERSE) demonstrated to be responsible for calcium modulation in mammals. This report demonstrates that the anomalous 60 kDa gel migration of mammalian CRT is conserved in rainbow trout and that CRT exists primarily as a dimer or oligomer in all tissues tested, excluding muscle and sperm in which it exists as a single polypeptide. Although it contains a potential N-glycosylation site, rainbow trout CRT is not subject to N-type glycosylation. Through the use of reverse transcriptase (RT) PCR along with western blotting, in both primary cultured leukocytes and the macrophage cell line RTS11, this report demonstrates that, unlike mammals, rainbow trout CRT is not strongly up-regulated by the calcium homeostasis antagonists, A23187 and thapsigargin, but is present on the cell surface of PHA-stimulated leukocytes. Taken together, this data suggests that CRT may have an alternative mode of regulation or function in fish.

Institutional variety in communications regulation. Classification scheme and empirical evidence from Austria

In recent decades, major regulatory reforms have changed the role of the state in the liberalised and convergent communications sectors of developed economies worldwide. The central characteristics of this transformed statehood in communications are, inter alia, a rising importance of independent national regulatory agencies (NRAs) and a growing reliance on alternative modes of regulation, i.e. self- and co-regulation. While the advent and activities of NRAs are often analysed in current literature, the institutional variety and regulatory contributions of private actors through self- and co-regulation are largely neglected. This article contributes to closing this research gap. A newly developed classification scheme of regulatory modes makes it possible to grasp the numerous and often intertwined contributions of both state and private actors. Furthermore, a case study of Austrian regulatory institutions active in the convergent communications sector demonstrates the potential of this new analytical tool and provides an in-depth analysis of various kinds of self- and co-regulation, which have substantially increased in communications regulation in Austria in the past decade.

Effects of carriage and expression of the Tn10 tetracycline-resistance operon on the fitness of Escherichia coli K12.

We have been examining the consequences of alternative modes of regulation of plasmid-borne, Tn10-encoded tetracycline resistance for the fitness of Escherichia coli. In a tetracycline-free environment, we measured the effects on fitness that were caused by (1) maximally induced expression of the resistance operon, (2) low-level constitutive expression of the resistance protein, (3) residual expression of the repressed resistance operon, (4) carriage of the resistance operon, (5) the remainder of the plasmid genome, and (6) hyperexpression of the repressor protein. We observed large reductions in fitness that were associated with induction and with constitutive expression of the tetracycline-resistance protein, but there was no discernible effect of hyperexpression of the repressor protein. We also observed a small reduction in fitness associated with the remainder of the plasmid genome. However, any reductions in fitness that were caused by residual expression and by carriage of the repressed operon were not more than 0.3%. We conclude that tight gene regulation has eliminated antagonistic pleiotropic effects of the resistance gene on fitness, so that possession of an inducible Tn10-encoded tetracycline-resistance operon imposes essentially no burden in the absence of antibiotic.

Adaptation in micro-organisms: Variation in macromolecular composition with growth rate

A model of bacterial population maintained in a steady state of sustained exponential growth is developed. The analysis is based essentially on a stochastic model of protein synthesis on labile mRNA's described in earlier communications. Two basic postulates: (1) co-ordinate synthesis of ribosomal proteins and (2) free ribosomal proteins in the pool functioning as a positive control element in the synthesis of rRNA provide the necessary framework for biogenesis of ribosomes. Macromolecular compositions of bacterial cells, with respect to RNA and protein contents at a gross level, are defined in terms of various kinetic parameters related to protein synthesis and maturation of ribosomes. Three alternative modes of regulation operating at the level of (i) functional efficiency of ribosomes, (ii) transcription of rRNA and (iii) differential synthesis rate of ribosomal proteins have been analysed. It is concluded that while the observed variations in macromolecular compositions of bacterial cells with growth rate constant at medium to high growth rates are compatible with (iii), the regulation at the level of functional efficiency of ribosomes (i) may be important at low growth rates.