Killing of Bacillus spores is mediated by nitric oxide and nitric oxide synthase during glycoconjugate–enhanced phagocytosis

Nitric oxide (NO) is a signaling and defense molecule of major importance. NO endows macrophages with bactericidal, cytostatic as well as cytotoxic activity against various pathogens. Bacillus spores can produce serious diseases, which might be attenuated if macrophages were able to kill the spores on contact. Present research was carried out to study whether glycoconjugates stimulated NO and nitric oxide synthase (NOS2) production during phagocytosis killing of Bacillus spores. Murine macrophages exposed to glycoconjugate-treated spores induced NOS2 and NO production that was correlated with high viability of macrophages and killing rate of bacterial spores. Increased levels of inducible NOS2 and NO production by macrophages in presence of glycoconjugates suggested that the latter provide an activation signal directed to macrophages. Glycoconjugates were shown to exert a protective influence, sparing macrophages from spore-induced cell death. In presence of glycoconjugates, macrophages efficiently kill the organisms. Without glycoconjugate activation, murine macrophages were ineffective at killing Bacillus spores. These results suggest that glycoconjugates promote killing of Bacillus spores by blocking spore-induced macrophage cell death, while increasing their activation level and NO and NOS2 production. Glycoconjugates suggest novel antimicrobial approaches to prevention and treatment of infection caused by bacterial spores.     

Quantitative profiling of prostaglandins as oxidative stress biomarkers in vitro and in vivo by negative ion online solid phase extraction – Liquid chromatography–tandem mass spectrometry

Free radical-mediated oxidation of arachidonic acid to prostanoids has been implicated in a variety of pathophysiological conditions such as oxidative stress. Here, we report on the development of a liquid chromatography–mass spectrometry method to measure several classes of prostaglandin derivatives based on regioisomer-specific mass transitions down to levels of 20 pg/ml applied to the measurement of prostaglandin biomarkers in primary hepatocytes. The quantitative profiling of prostaglandin derivatives in rat and human hepatocytes revealed the increase of several isomers on stress response. In addition to the well-established markers for oxidative stress such as 8-iso-prostaglandin F_2α and the prostaglandin isomers PE₂ and PD₂, this method revealed a significant increase of 15R-prostaglandin D₂ from 236.1 ± 138.0 pg/1E6 cells in untreated rat hepatocytes to 2001 ± 577.1 pg/1E6 cells on treatment with ferric NTA (an Fe³⁺ chelate with nitrilotriacetic acid causing oxidative stress in vitro as well as in vivo). Like 15R-prostaglandin D₂, an unassigned isomer that revealed a more significant increase than commonly analyzed prostaglandin derivatives was identified. Mass spectrometric detection on a high-resolution instrument enabled high-quality quantitative analysis of analytes in plasma levels from rat experiments, where increased concentrations up to 23-fold change treatment with Fe(III)NTA were observed.     

Variations of chromatin, tubulin and actin structures in primate oocytes arrested during in vitro maturation and fertilization--what is this telling us about the relationships between cytoskeletal and chromatin meiotic defects?

A nonhuman primate model was applied to investigate the relationships between variations in the organization of microtubules, microfilaments, and chromatin in metaphase I and metaphase II oocytes. Marmoset oocytes were subjected to in vitro maturation and coincubation with sperm. Oocytes which failed to cleave were investigated for chromatin, tubulin, and actin using Hoechst 33258, fluorescein isothiocyanate (FITC)-labeled alpha-tubulin antibody and rhodamine-labeled phalloidin, respectively. Spindles were categorized according to size, shape and microtubule organization: normal, large, multipolar, disorganized, absent spindle, and spindles with broad poles. Actin caps were categorized as: normal, small, split, and disorganized. Chromosomal condensation and alignment were described as normal or abnormal. Improper chromosomal condensation was associated with both abnormal microfilament and microtubule arrangement. This was further associated with abnormal actin organization, disorientation and late stabilization of microtubules, but not related to abnormal organization of spindle poles. Chromosomal misalignment was associated with disorientation and late stabilization of tubulin, but not to broad spindle pole. Additionally, abnormal actin polarization appeared not to be related to abnormal spindle poles. The model system presented in this study could be used as an experimental platform for studying the contribution of different factors to the exactness of late meiotic events in primate oocytes. The present study provides basic information on spindle, chromosome, and actin normal and abnormal organization, which can be observed in in vitro matured, but failed to cleave primate oocytes.