Some but not All Tetrahymena Species Destroy Monolayer Cultures of Cells from a Wide Range of Tissues and Species

The activities of Tetrahymena corlissi, Tetrahymena thermophila, and Tetrahymena canadensis were studied in coculture with cell lines of insects, fish, amphibians, and mammals. These ciliates remained viable regardless of the animal cell line partner. All three species could engulf animal cells in suspension. However, if the animal cells were monolayer cultures, the monolayers were obliterated by T. corlissi and T. thermophila. Both fibroblast and epithelial monolayers were destroyed but the destruction of human cell monolayers was done more effectively by T. thermophila. By contrast, T. canadensis was unable to destroy any monolayer. At 4 °C T. thermophila and T. corlissi did not carryout phagocytosis and did not destroy monolayers, whereas T. canadensis was able to carryout phagocytosis but still could not destroy monolayers. Therefore, monolayer destruction appeared to require phagocytosis, but by itself this was insufficient. In addition, the ciliates expressed a unique swimming behavior. Tetrahymena corlissi and T. thermophila swam vigorously and repeatedly into the monolayer, which seemed to loosen or dislodge cells, whereas T. canadensis swam above the monolayer. Therefore, differences in swimming behavior might explain why T. corlissi has been reported to be a pathogen but T. canadensis has not.     

High mobility group box 1 levels in large vessel vasculitis are not associated with disease activity but are influenced by age and statins

IntroductionTakayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV.MethodsTwenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay.ResultsIn GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 ± 4.19 ng/ml vs. 4.17 ± 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45–2.10) ng/ml vs. 1.46 (0.89–3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63–2.16) ng/ml vs. 0.75 (0.39–2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29–1.46) ng/ml vs. 1.93 (0.88–3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status.ConclusionsPatients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV.     

Cecal ligation and puncture: the gold standard model for polymicrobial sepsis?

Sepsis is a serious medical condition characterized by dysregulated systemic inflammatory responses followed by immunosuppression. To study the pathophysiology of sepsis, diverse animal models have been developed. Polymicrobial sepsis induced by cecal ligation and puncture (CLP) is the most frequently used model because it closely resembles the progression and characteristics of human sepsis. Here we summarize the role of several immune components in the pathogenesis of sepsis induced by CLP. However, several therapies proposed on the basis of promising results obtained by CLP could not be translated to the clinic. This demonstrates that experimental sepsis models do not completely mimic human sepsis. We propose several strategies to narrow the gap between experimental sepsis models and clinical sepsis, including targeting factors that contribute to the immunosuppressive phase of sepsis, and reproducing the heterogeneity of human patients.     

Quantum chemical modeling of perovskite: An investigation of piezoelectricity in ferrite of yttrium

In a previous article, we used Hartree-Fock (HF) theory to study the piezoelectricity in BaTiO₃. In this paper, we applied the Douglas-Kroll-Hess second order scalar relativistic method to investigate the possible piezoelectric properties in the perovskite YFeO₃ structure, which has not yet been studied experimentally. The 30s20p13d and 31s21p17d Gaussian basis sets for the Fe (⁵D) and Y (²D) atoms, respectively, were built with the Generator Coordinate HF method. After contraction to [13s7p5d] and [13s8p7d], in combination with the 20s14p/6s4p basis set for the O (³P) atom from literature, they had their quality evaluated using calculations of the total and the orbital energies for the ²FeO⁺¹ and ¹YO⁺¹ fragments. The dipole moment, the total energy, and the total atomic charges in YFeO₃ in C_s space group were calculated. The results and the analysis lead us to believe that the perovskite YFeO₃ does not present piezoelectric properties.     

Backbone and side chain 1H, 15N and 13C assignments of the KSR1 CA1 domain

The backbone and side chain resonance assignments of the murine KSR1 CA1 domain have been determined based on triple-resonance experiments using uniformly [¹³C, ¹⁵N]-labeled protein. This assignment is the first step towards the determination of the three-dimensional structure of the unique KSR1 CA1 domain.     

Proteins associated with cork formation in Quercus suber L. stem tissues

Cork (phellem) formation in Quercus suber stem was studied by proteomic analysis of young shoots of increasing age (Y0, Y1 and Y4) and recently-formed phellem (Y8Ph) and xylem (Y8X) from an 8-year-old branch. In this study 99 proteins were identified, 45 excised from Y8X and 54 from Y8Ph. These ones, specifically associated with phellem, are of "carbohydrate metabolism" (28%), "defence" (22%), "protein folding, stability and degradation" (19%), "regulation/signalling" (11%), "secondary metabolism" (9%), "energy metabolism" (6%), and "membrane transport" (2%). The identification in phellem of galactosidases, xylosidases, apiose/xylose synthase, laccases and diphenol oxidases suggests intense cell wall reorganization, possibly with participation of hemicellulose/pectin biosynthesis and phenol oxidation. The identification of proteasome subunits, heat shock proteins, cyclophylin, subtilisin-like proteases, 14-3-3 proteins, Rab2 protein and enzymes interacting with nucleosides/nucleic acids gives additional evidence for cellular reorganization, involving cellular secretion, protein turnover regulation and active control processes. The high involvement in phellem of defence proteins (thioredoxin-dependent peroxidase, glutathione-S-transferase, SGT1 protein, cystatin, and chitinases) suggests a strong need for cell protection from the intense stressful events occurring in active phellem, namely, desiccation, pests/disease protection, detoxification and cell death. Identically, highly enhanced defence functions were previously reported for potato periderm formation.     

Species-specific codon context rules unveil non-neutrality effects of synonymous mutations

BackgroundCodon pair usage (codon context) is a species specific gene primary structure feature whose evolutionary and functional roles are poorly understood. The data available show that codon-context has direct impact on both translation accuracy and efficiency, but one does not yet understand how it affects these two translation variables or whether context biases shape gene evolution.ConclusionsSince in vivo studies provide evidence for a role of codon context on decoding fidelity in E. coli and for decoding efficiency in mammalian cells, our data support the hypothesis that, like codon usage, codon context modulates the evolution of gene primary structure and fine tunes the structure of open reading frames for high genome translational fidelity and efficiency in the 3 domains of life.     

Acetylcholine Release Induced by the Volatile Anesthetic Sevoflurane in Rat Brain Cortical Slices

1. We have investigated the effect of the volatile anesthetic sevoflurane on acetylcholine (ACh) release from rat brain cortical slices. 2. The release of [3H]-ACh into the incubation fluid was studied after labeling the tissue ACh with [methyl-3H]-choline chloride. 3. We observed that sevoflurane induced an increase on the release of ACh that was dependent on incubation time and anesthetic concentration. The sevoflurane-induced ACh release was not blocked by tetrodotoxin (TTX) and therefore was independent of sodium channels. In addition, the sevoflurane effect was not blocked by ethylene glycol-bis(beta-aminoethyl ether (EGTA) or cadmium (Cd2+), thus independent of extracellular calcium. 4. The sevoflurane-induced ACh release was inhibited by 1,2-bis (2-aminophenoxy) ethane-N,N,N',N'-tetra-acetic acid (BAPTA-AM), suggesting the involvement of intracellular calcium-sensitive stores in the process. Dantrolene, an inhibitor of ryanodine receptors, had no effect but 2-aminoethoxydiphenylborate (2-APB), a membrane-permeable inhibitor of inositol 1,4,5-triphosphate receptor inhibited the sevoflurane-induced release of ACh. 5. It is concluded that sevoflurane-induced release of ACh in brain cortical slices involves the mobilization of calcium from IP3-sensitive calcium stores.