Pathogenic nontuberculous mycobacteria resist and inactivate cathelicidin: implication of a novel role for polar mycobacterial lipids

Includes bibliographic references.Nontuberculous mycobacteria (NTM) are a large group of environmental organisms with worldwide distribution, but only a relatively few are known to be pathogenic. Chronic, debilitating lung disease is the most common manifestation of NTM infection, which is often refractory to treatment. The incidence and prevalence of NTM lung disease are increasing in the United States and in many parts of the world. Hence, a more complete understanding of NTM pathogenesis will provide the foundation to develop innovative approaches to treat this recalcitrant disease. Herein, we domonstrate that several species of NTM show broad resistance to the antimicrobial peptide, cathelicidin (LL-37). Resistance to LL-37 was not significantly different between M. avium that contain serovar-specific glycopeptidolipid (GPL, M. aviumˢˢᴳᴾᴸ) and M.avium that do not (M. aviumᐞˢˢᴳᴾᴸ). Similarly, M. Abscessus containing non-specific GPL (M. abscessusⁿˢᴳᴾᴸ⁽⁺⁾) or lacking nsGPL (M. abscessusⁿˢᴳᴾᴸ⁽⁻⁾) remained equally resistant to LL-37. These findings would support the notion that GPL are not the components responsible for NTM resistance to LL-37. Unexpectedly, the growth of M. abscessusⁿˢᴳᴾᴸ⁽⁻⁾ increased with LL-37 or scrambled LL-37 peptide in a dose-dependent fashion. We also discovered that LL-37 exposed to NTM had reduced antimicrobial activity, and initial work indicates that this is likely due to inactivation of LL-37 by lipid component(s) of the NTM cell envelope. We conclude that pathogenic NTM resist and inactivate LL-37. The mechanism by which NTM circumvent the antimicrobial activity of LL-37 remains to be determined

The methodology of conception development of place brand

Бренд рассматривается как знаковая система, анализируются три структурных ее компонента: синтаксис, семантика и прагматика. Синтаксис раскрывается как метафорическая или метонимическая структура, семантика эксплицируется через социальные значения бренда, а прагматика — посредством определения идентификационного или проекционного механизма овладения брендом.The brand is seen as a sign system, three structural components are analyzed: syntax, semantics and pragmatics. Syntax is revealed as a metaphorical or metonymic structure, semantics is explicated through the social values of the brand, and pragmatics — through definition of identification or projection mechanism of brand master

On the protein residues that control the yield and kinetics of O(630) in the photocycle of bacteriorhodopsin.

The effects of pH on the yield (phi(r)), and on the apparent rise and decay constants (k(r), k(d)), of the O(630) intermediate are important features of the bacteriorhodopsin (bR) photocycle. The effects are associated with three titration-like transitions: 1) A drop in k(r), k(d), and phi(r) at high pH [pK(a)(1) approximately 8]; 2) A rise in phi(r) at low pH [pK(a)(2) approximately 4.5]; and 3) A drop in k(r) and k(d) at low pH [pK(a)(3) approximately 4. 5]. (pK(a) values are for native bR in 100 mM NaCl). Clarification of these effects is approached by studying the pH dependence of phi(r), k(r), and k(d) in native and acetylated bR, and in its D96N and R82Q mutants. The D96N experiments were carried out in the presence of small amounts of the weak acids, azide, nitrite, and thiocyanate. Analysis of the mutant's data leads to the identification of the protein residue (R(1)) whose state of protonation controls the magnitude of phi(r), k(r), and k(d) at high pH, as Asp-96. Acetylation of bR modifies the Lys-129 residue, which is known to affect the pK(a) of the group (XH), which releases the proton to the membrane exterior during the photocycle. The effects of acetylation on the O(630) parameters reveal that the low-pH titrations should be ascribed to two additional protein residues R(2) and R(3). R(2) affects the rise of phi(r) at low pH, whereas the state of protonation of R(3) affects both k(r) and k(d). Our data confirm a previous suggestion that R(3) should be identified as the proton release moiety (XH). A clear identification of R(2), including its possible identity with R(3), remains open

Caspase-3-independent apoptotic pathways contribute to interleukin-32gamma-mediated control of Mycobacterium tuberculosis infection in THP-1 cells

Contains fulltext : 154717.pdf (publisher's version ) (Open Access)BACKGROUND: Macrophages are the primary effector cells responsible for killing Mycobacterium tuberculosis (MTB) through various mechanisms, including apoptosis. However, MTB can evade host immunity to create a favorable environment for intracellular replication. MTB-infected human macrophages produce interleukin-32 (IL-32). IL-32 is a pro-inflammatory cytokine and has several isoforms. We previously found that IL-32gamma reduced the burden of MTB in human macrophages, in part, through the induction of caspase-3-dependent apoptosis. However, based on our previous studies, we hypothesized that caspase-3-independent death pathways may also mediate IL-32 control of MTB infection. Herein, we assessed the potential roles of cathepsin-mediated apoptosis, caspase-1-mediated pyroptosis, and apoptosis-inducing factor (AIF) in mediating IL-32gamma control of MTB infection in THP-1 cells. RESULTS: Differentiated human THP-1 macrophages were infected with MTB H37Rv alone or in the presence of specific inhibitors to caspase-1, cathepsin B/D, or cathepsin L for up to four days, after which TUNEL-positive cells were quantified; in addition, MTB was quantified by culture as well as by the percentage of THP-1 cells that were infected with green fluorescent protein (GFP)-labeled MTB as determined by microscopy. AIF expression was inhibited using siRNA technology. Inhibition of cathepsin B/D, cathepsin L, or caspase-1 activity significantly abrogated the IL-32gamma-mediated reduction in the number of intracellular MTB and of the percentage of GFP-MTB-infected macrophages. Furthermore, inhibition of caspase-1, cathepsin B/D, or cathepsin L in the absence of exogenous IL-32gamma resulted in a trend toward an increased proportion of MTB-infected THP-1 cells. Inhibition of AIF activity in the absence of exogenous IL-32gamma also increased intracellular burden of MTB. However, since IL-32gamma did not induce AIF and because the relative increases in MTB with inhibition of AIF were similar in the presence or absence of IL-32gamma, our results indicate that AIF does not mediate the host-protective effect of IL-32gamma against MTB. CONCLUSIONS: The anti-MTB effects of IL-32gamma are mediated through classical caspase-3-dependent apoptosis as well as caspase-3-independent apoptosis