Analysis of common antigen of flagella in Bacillus cereus and Bacillus thuringiensis

Abstract Flagellar antigen of Bacillus cereus H.1 was purified and tested for serodiagnostic antigen by ELISA. The antibody against the flagellar antigen of B. cereus H.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of B. cereus . This common flagellar antigen of B. cereus was found to be due to 61-kDa protein by SDS-PAGE and immunoblot assay. Monoclonal antibody H15A5 against common antigenic epitope of B. cereus also reacted with flagellar antigens of 21 strains of Bacillus thuringiensis by ELISA. This monoclonal antibody reacted with the 61-kDa protein of the flagella of B. cereus H.1 and H.2 and B. thuringiensis Kurstaki HD1, Alesti and Aizawai juroi by immunoblot analysis. These results indicated that the common antigenic epitope of the 61-kDa protein existed in the flagella both of B. cereus and B. thuringiensis .     

Starvation of a clonal osteoblast-like cell line, MOB 3-4-F2, down-regulates prostaglandin E2 receptors but increases cAMP response to prostaglandin E2.

Prostaglandin E2 (PGE2) stimulated cAMP production in the MOB 3-4-F2 cell line, a subclone of the osteoblast-like MOB 3-4 cell line. After being cultured in alpha-minimum essential medium supplemented with 10% heat-inactivated foetal calf serum (HIFCS), cells responded to PGE2 (greater than or equal to 50 ng/ml) with a small, but significant, increase in cAMP production. This response did not vary with duration of culture. In 2% HIFCS-containing medium, despite their lower basal cAMP level, cells responded to PGE2 (greater than or equal to 5 ng/ml) with strikingly increased cAMP production. In addition, prolonged culture in this serum-deficient medium enhanced this response. On the other hand, culture of cells in 2% HIFCS-containing medium decreased the apparent number of PGE2 receptors, which was also enhanced by prolonged culture, without effect on their apparent affinity. Their number in 10% HIFCS-containing medium, more than that in 2% HIFCS-containing medium, was almost constant, independent of the culture period. Starvation of MOB 3-4-F2 cells in serum-deficient medium, therefore, appeared to down-regulate PGE2 receptors but increase the cAMP response to PGE2. Moreover, prolonged starvation of cells appeared to facilitate these phenomena. Our findings suggest that cAMP response to PGE2 does not always reflect the number of available PGE2 receptors in the cells.     

Concurrent Bursty Behavior of Social Sensors in Sporting Events

The advent of social media expands our ability to transmit information and connect with others instantly, which enables us to behave as “social sensors.” Here, we studied concurrent bursty behavior of Twitter users during major sporting events to determine their function as social sensors. We show that the degree of concurrent bursts in tweets (posts) and retweets (re-posts) works as a strong indicator of winning or losing a game. More specifically, our simple tweet analysis of Japanese professional baseball games in 2013 revealed that social sensors can immediately react to positive and negative events through bursts of tweets, but that positive events are more likely to induce a subsequent burst of retweets. We confirm that these findings also hold true for tweets related to Major League Baseball games in 2015. Furthermore, we demonstrate active interactions among social sensors by constructing retweet networks during a baseball game. The resulting networks commonly exhibited user clusters depending on the baseball team, with a scale-free connectedness that is indicative of a substantial difference in user popularity as an information source. While previous studies have mainly focused on bursts of tweets as a simple indicator of a real-world event, the temporal correlation between tweets and retweets implies unique aspects of social sensors, offering new insights into human behavior in a highly connected world.     

Hypertonic saline aerosol increases airway reactivity in the canine lung periphery.

Hyperventilation with dry air increases airway surface fluid (ASF) osmolality and causes acute mucosal injury, leukocyte infiltration, and delayed airway obstruction and hyperreactivity in canine peripheral airways. The purpose of this study was to determine whether ASF hypertonicity per se can account for these hyperventilation-associated effects. We first measured ASF osmolality before and after normal (NSC) and hypertonic (HSC) saline aerosol challenges to document the magnitude of hypertonicity produced by these stimuli. We then measured canine peripheral airway resistance and reactivity to hypocapnia and aerosolized histamine before and after NSC and HSC. Cells and eicosanoid mediators recovered in bronchoalveolar lavage fluid at 5 and 24 h after NSC and HSC were examined. We found that HSC but not NSC caused acute ASF hyperosmolality, increased mediator release, and delayed airway hyperreactivity in the absence of mucosal injury and leukocyte infiltration. These observations suggest that ASF hyperosmolality contributes to the development of the late-phase response to hyperventilation and further suggest that hyperventilation-induced mucosal injury independently initiates leukocyte infiltration and late-phase airway obstruction.     

Purification of acidic fibroblast growth factor from bovine heart and its localization in the cardiac myocytes

We found an endogenous growth factor, referred to here as heart-derived growth factor (HDGF), that stimulates the proliferation of vascular endothelial cells. HDGF was purified from bovine myocardium using a procedure that involves denaturation of undesired proteins with methanol and chloroform. Soluble HDGF was purified essentially to homogeneity in a single step by heparin affinity chromatography. The purified HDGF was identified to be acidic fibroblast growth factor based on the following properties: molecular weight of 18,000, isoelectric point of 5.2, amino acid composition and sequence, its dissociation from a heparin affinity column at 0.9 M NaCl, potentiation of activity in the presence of heparin, and antigenicity. Our yield of HDGF was 500 micrograms/kg of tissue. Antiserum raised to HDGF localized HDGF in the cardiac myocytes in culture. These data indicate that a large amount of acidic fibroblast growth factor is present in the heart, and the cardiac myocytes are likely to be a major source of it.     

Gender and Age Differences in the Suppressive Effect of a 50 Hz Electric Field on the Immobilization-Induced Increase of Plasma Glucocorticoid in Mice

We developed an experimental system to characterize the suppressive effect of extremely low-frequency (ELF) electric fields (EFs) on the stress response. We assessed differences in the EF effects by age and gender. Control, EF-alone, immobilization-alone, and co-treated groups were subjected to an EF (50 Hz, 10 kV/m). Co-treated mice were exposed to the EF for 60 min, with immobilization during the latter half. Our results indicate that the suppressive effects of ELF EFs on the stress response in immobilized mice occur regardless of gender or age. As stress plays an important role in the onset and progression of various diseases, these findings may have broad implications for understanding the efficacy of EFs in animal, and perhaps human, health. Bioelectromagnetics. 2020;41:156–163. © 2019 Bioelectromagnetics Society.