Probing the Energetic Metabolism of Resting Cysts under Different Conditions from Molecular and Physiological Perspectives in the Harmful Algal Blooms-Forming Dinoflagellate Scrippsiella trochoidea

Energetic metabolism is essential in maintaining the viability of all organisms. Resting cysts play important roles in the ecology of dinoflagellates, particularly for harmful algal blooms (HABs)-causative species. However, the energetic metabolism underlying the germination potency maintenance of resting cysts of dinoflagellate have been extremely scarce in studies from physiological and, particularly, molecular perspectives. Therefore, we used the cosmopolitan Scrippsiella trochoidea as a representative of HABs-forming and cyst-producing dinoflagellates in this work to obtain novel insights into the molecular mechanisms, regulating the energetic metabolism in dinoflagellate resting cysts, under different physical condition. As the starting step, we established a cDNA subtractive library via suppression subtractive hybridization (SSH) technology, from which we screened an incomplete sequence for the β subunit of ATP synthase gene (β-F1-ATPase), a key indicator for the status of cell’s energetic metabolism. The full-length cDNA of β-F1-ATPase gene from S.trochoidea (Stβ-F1-ATPase) was then obtained via rapid amplification of cDNA ends (RACE) (Accession: MZ343333). Our real-time qPCR detections, in vegetative cells and resting cysts treated with different physical conditions, revealed that (1) the expression of Stβ-F1-ATPase in resting cysts was generally much lower than that in vegetative cells, and (2) the Stβ-F1-ATPase expressions in the resting cysts under darkness, lowered temperature, and anoxia, and during an extended duration of dormancy, were significantly lower than that in cysts under the condition normally used for culture-maintaining (a 12 h light:12 h dark cycle, 21 °C, aerobic, and newly harvested). Our detections of the viability (via Neutral Red staining) and cellular ATP content of resting cysts, at the conditions corresponding to the abovementioned treatments, showed that both the viability and ATP content decreased rapidly within 12 h and then maintained at low levels within the 4-day experimentation under all the three conditions applied (4 °C, darkness, and anoxia), which are well in accordance with the measurements of the transcription of Stβ-F1-ATPase. These results demonstrated that the energy consumption of resting cysts reaches a low, but somehow stable, level within a short time period and is lower at low temperature, darkness, and anoxia than that at ambient temperature. Our work provides an important basis for explaining that resting cysts survive long-term darkness and low temperature in marine sediments from molecular and physiological levels.

Effects of P-MAPA as Immunomodulator on Markers for Energy Metabolism in Bladder Cancer

Introduction This study characterized and compared cellular energetic metabolism features in the treatment of chemically induced non-muscle invasive bladder cancer (NMIBC) in Fischer 344 rats that were submitted to intravesical immunotherapies with P-MAPA (Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride) and Bacillus Calmette-Guérin (BCG). Methods Rat urinary bladder samples from Control, NMIBC (Cancer), NMIBC+BCG and NMIBC+P-MAPA groups were submitted to histopathological and western blotting analyses for the following proteins: GLUT 1, PFK, GAPDH, HADHSC, β-F1-ATPase, AMPK and mTOR. Results P-MAPA Intravesical treatment was effective in tumor regression and histologic recovery of the urinary bladder in the NMIBC. There was a significant increase in protein levels of GLUT 1, mTOR, GAPDH and HADHSC in the NMIBC+P-MAPA group. It was observed an increase in protein levels of PFK and β-F1-ATPase and a significant reduction in protein levels of AMPk in the NMIBC group. Conclusions Our results showed that immunotherapy with P-MAPA may be an alternative in the treatment of NMIBC, especially in cases where BCG therapy failure, as evidenced by the effect of P-MAPA on tumor regression.