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Increased temperature and acidification are two important environmental factors affecting algal growth in marine ecosystems with the increase of atmospheric CO2. The dinoflagellate Amphidinium carterae and the diatom Phaeodactylum tricornutum were chosen to study the effect of warming and acidification on their sulfate assimilation and reduction processes by continuous incubation at different temperatures (15, 20 and 25 °C) and pHNBS values (8.10, 7.80 and 7.60). Variations in associated sulfur compounds, namely sulfate, dimethylsulfoniopropionate (DMSP), dimethylsulfide (DMS) and acrylic acid (AA) were observed. The largest sulfate uptake was at 25 °C for A. carterae and at 20 °C for P. tricornutum, however, the optimal growth temperature for both microalgae was 20 °C. The release of DMSP and DMS decreased in A. carterae while they increased in P. tricornutum under the condition of increased temperature. Seawater acidification increased the uptake of sulfate and promoted the growth of the microalgae. Acidification also reduced the release of DMSP, dissolved DMSP (DMSPd), DMS and AA from A. carterae with mean values of 55%, 22%, 9% and 40%, respectively. However, acidification increased the release of DMSP and DMSPd by P. tricornutum with mean values of 44% and 186%, the release of DMS was inhibited (25%) and with no significant difference in the release of AA (2%). Amino acids were found to inhibit the uptake of sulfate by the two microalgae, and the inhibitory effect of cysteine was found to be stronger than that of methionine. The inhibitory effect of amino acids was temperature sensitive and relatively weak at 20 °C. Besides, acidification could enhance the inhibitory effect and was evident in A. carterae. The sulfur metabolism intermediates (cysteine and methionine) have a feedback regulation effect on the sulfate absorption process of algae. [ABSTRACT FROM AUTHOR]

Dimethyl sulfide (DMS) is an important and dominant trace gas that is transferred from the ocean to the atmosphere; however, the production of DMS from marine algae is still rudimentary, with the enzymatic cleavage of dimethylsulfoniopropionate (DMSP) to DMS and acrylic acid (AA), one of the main considered pathways. Dissolved DMSP (DMSPd) was supplied to batch cultures of Prorocentrum minimum at different algal growth stages and the kinetics of overall DMSPd consumption and DMS (AA) production were investigated. The kinetics of overall DMSPd consumption and DMS (AA) production from DMSPd were different during the growth cycle. The cultures displayed Michaelis–Menten-type kinetics for DMS production during the entire growth period, which yielded an apparent half-saturation constant (Km(app)) value of 37.8 ± 12.8 μM and a maximum rate (Vmax) value of 75.6 ± 12.2 nmol min−1 (1010 cells)−1. The production rates of AA had a nearly linear fit over the concentration range of the added DMSPd except during mid-exponential growth phase. A Km(app) value of 1.73 ± 0.75 μM and a Vmax value of 2.36 ± 0.12 μmol min−1 (1010 cells)−1 were observed. The ratio of DMS/AA increased with the concentration of the added DMSPd, which was less than 12% during the entire growth period. The low ratios of DMS/(DMSP + AA), which ranged from 0.01 to 1.83%, demonstrate that degradation of DMSP tends to take a non-DMS-production pathway. The ratios of AA/(DMSP + AA) varied from 9 to 95% during the stationary phase and from 6 to 69% during the senescent phase and declined with substrate concentration when different concentrations of DMSPd were added. The degradation ratios of DMSPd were related to the initial concentrations of DMSPd. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a non-traditional regulator of the growth of plants and phytoplankton. Here, the growth of five marine phytoplankton species, Platymonas helgolandica var. tsingtaoensis, Platymonas subcordiformis, Skeletonema costatum, Gymnodinium sp., and Prorocentrum donghaiense, was monitored, and carbonate system parameters in the culture media were determined after adding different concentrations of NO and sodium nitroprusside (SNP, NO donor) solutions. The two dietary algae (P. helgolandica var. tsingtaoensis and P. subcordiformis) and three red tide algae (S. costatum, Gymnodinium sp., and P. donghaiense) showed different responses to the same NO concentration. The red tide algae were more sensitive to exogenous NO than the dietary algae. NO with a concentration of 1.4 × 10−6 mol L−1 had the optimal stimulatory effect on the growth of the microalgae and increased the cell density by 9.8–38.3%. SNP solution with a concentration of 100 μmol L−1 inhibited the growth of the two dietary algae, and the cell density decreased by 38.8–84.3%. The addition of 10 μmol L−1 SNP solution to the three red tide algae decreased the cell density by 95.3–99.9%. Low concentrations of SNP (0.1 μmol L−1 for the two dietary algae and 0.01 μmol L−1 for the red tide algae) slightly promoted the growth of microalgae. High concentrations of NO (100 μmol L−1 SNP) inhibited CO2 assimilation, whereas low concentrations of NO (0.01–1.0 μmol L−1 SNP) promoted CO2 assimilation, indicating that NO participates in the regulation of photosynthesis. [ABSTRACT FROM AUTHOR]

Ocean acidification and global warming might affect the production of dimethylsulfoniopropionate (DMSP), dimethylsulfide (DMS), and dissolved acrylic acid (AAd) by marine phytoplankton. Monoculture incubation experiments were conducted with the dinoflagellate Amphidinium carterae to investigate the effects of elevated CO2 concentration and temperature on growth and productions of DMSP, DMS, and AAd. Two pCO2 levels were set as 400 and 1000 μatm, and two temperatures were set as 20 and 23 °C. The growth of A. carterae remained unaffected by an increase of CO2 to 1000 μatm and a rise of temperature of 3 °C. Moreover, the elevated CO2 concentration and temperature had no significant effects on the concentrations and cell-normalized concentrations of DMSP, DMS, and AAd. No additive or synergistic effects of elevated CO2 concentration and temperature on A. carterae were observed, indicating that A. carterae was insensitive to elevated CO2 and temperature in short time incubation. [ABSTRACT FROM AUTHOR]

Cardiomyocyte proliferation and regeneration are key to the functional recovery of myocardial tissue from injury. In the recent years, studies on cardiomyocyte proliferation overturned the traditional belief that adult cardiomyocytes permanently withdraw from the cell cycle activity. Hence, targeting cardiomyocyte proliferation is one of the potential therapeutic strategies for myocardial regeneration and repair. To achieve this, a deep understanding of the fundamental mechanisms involved in cardiomyocyte cell cycle as well as differences between neonatal and adult cardiomyocytes' cell cycle activity is required. This review focuses on the recent progress in understanding of cardiomyocyte cell cycle activity at different life stages viz., gestation, birth, and adulthood. The temporal expression/activities of major cell cycle activators (cyclins and CDKs), inhibitors (p21, p27, p57, p16, and p18), and cell-cycle-associated proteins (Rb, p107, and p130) in cardiomyocytes during gestation and postnatal life are described in this review. The influence of different transcription factors and microRNAs on the expression of cell cycle proteins is demonstrated. This review also deals major pathways (PI3K/AKT, Wnt/β-catenin, and Hippo-YAP) associated with cardiomyocyte cell cycle progression. Furthermore, the postnatal alterations in structure and cellular events responsible for the loss of cell cycle activity are also illustrated. [ABSTRACT FROM AUTHOR]

Telomerase is a promising diagnostic and prognostic biomarker for cancers. Sensitive, simple, and reliable telomerase activity detection is vital for cancer diagnosis. Herein, we developed an ultrasensitive visualized assay for telomerase activity that combined the exponential amplification reaction (EXPAR) and lateral flow assay for easy and quick signal readout, which we termed as a lateral flow readout-EXPAR (LFR-EXPAR) assay. In the LFR-EXPAR assay, telomerase elongation products initiate the exponential amplification reaction, the generated trigger hybridizes with the reporter to form the recognition site of the nicking enzyme, and the nicking enzyme cuts the reporter strand. The degradation of the reporter can be detected with a universal lateral flow dipstick and read out with the naked eye. After conducting a series of proof-of-concept investigations, the LFR-EXPAR assay was found to achieve a sensitivity comparable to that of a TRAP (telomere repeat amplification protocol) assay. The LFR-EXPAR assay can be used to realize ultrasensitive and point-of-care detection of telomerase without requiring specialized instruments, holding great promise for early cancer diagnosis. [ABSTRACT FROM AUTHOR]