Alleviation of solar ultraviolet radiation (UVR)-induced photoinhibition in diatom Chaetoceros curvisetus by ocean acidification

2014 ◽  
Vol 95 (4) ◽  
pp. 661-667 ◽  
Author(s):  
Heng Chen ◽  
Wanchun Guan ◽  
Guoquan Zeng ◽  
Ping Li ◽  
Shaobo Chen
Keyword(s):  
Growth Rate ◽  
Ultraviolet Radiation ◽  
Ocean Acidification ◽  
Specific Growth Rate ◽  
Cell Density ◽  
Specific Growth ◽  
Photochemical Efficiency ◽  
Solar Ultraviolet Radiation ◽  
Chaetoceros Curvisetus ◽  
Solar Ultraviolet

The study aimed to unravel the interaction between ocean acidification and solar ultraviolet radiation (UVR) in Chaetoceros curvisetus. Chaetoceros curvisetus cells were acclimated to high CO2 (HC, 1000 ppmv) and low CO2 concentration (control, LC, 380 ppmv) for 14 days. Cell density, specific growth rate and chlorophyll were measured. The acclimated cells were then exposed to PAB (photosynthetically active radiation (PAR) + UV-A + UV-B), PA (PAR + UV-A) or P (PAR) for 60 min. Photochemical efficiency (ΦPSII), relative electron transport rate (rETR) and the recovery of ΦPSII were determined. HC induced higher cell density and specific growth rate compared with LC. However, no difference was found in chlorophyll between HC and LC. Moreover, ΦPSII and rETRs were higher under HC than LC in response to solar UVR. P exposure led to faster recovery of ΦPSII, both under HC and LC, than PA and PAB exposure. It appeared that harmful effects of UVR on C. curvisetus could be counteracted by ocean acidification simulated by high CO2 when the effect of climate change is not beyond the tolerance of cells.

Effects of ocean acidification and solar ultraviolet radiation on physiology and toxicity of dinoflagellate Karenia mikimotoi

Harmful Algae ◽  
2019 ◽  
Vol 81 ◽  
pp. 1-9 ◽  
Author(s):  
Xinjie Wang ◽  
Xinqian Feng ◽  
Yang Zhuang ◽  
Jianghuan Lu ◽  
Yang Wang ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Ocean Acidification ◽  
Solar Ultraviolet Radiation ◽  
Karenia Mikimotoi ◽  
Solar Ultraviolet

Specific growth rate and not cell density controls the general stress response in Escherichia coli

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1637-1648 ◽  
Author(s):  
Julian Ihssen ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Response ◽  
Specific Growth Rate ◽  
Cell Density ◽  
Specific Growth ◽  
Batch Cultures ◽  
General Stress Response ◽  
E Coli ◽  
Density Effects

In batch cultures of Escherichia coli, the intracellular concentration of the general stress response sigma factor RpoS typically increases during the transition from the exponential to the stationary growth phase. However, because this transition is accompanied by complex physico-chemical and biological changes, which signals predominantly elicit this induction is still the subject of debate. Careful design of the growth environment in chemostat and batch cultures allowed the separate study of individual factors affecting RpoS. Specific growth rate, and not cell density or the nature of the growth-limiting nutrient, controlled RpoS expression and RpoS-dependent hydroperoxidase activity. Furthermore, it was demonstrated that the standard E. coli minimal medium A (MMA) is not suitable for high-cell-density cultivation because it lacks trace elements. Previously reported cell-density effects in chemostat cultures of E. coli can be explained by a hidden, secondary nutrient limitation, which points to the importance of medium design and appropriate experimental set-up for studying cell-density effects.

Effects of N/P Atomic Ratio on the Growth of Alexandrium Tamarense at Various Initial Phosphate Concentrations

2012 ◽  
Vol 455-456 ◽  
pp. 1289-1296
Author(s):  
Shi Yong Wen ◽  
Dong Zhi Zhao ◽  
Li Li Song ◽  
Hua Long
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Cell Density ◽  
Specific Growth ◽  
Red Tide ◽  
Atomic Ratio ◽  
Maximum Specific Growth Rate ◽  
Alexandrium Tamarense ◽  
Nutrient Input ◽  
The Relationship

To reveal the relationship between nutrient input and red tide outbreaks, the effects of N/P atomic ratio on the specific growth rate of Alexandrium tamarense is analyzed under various initial phosphate concentrations in laboratory cultures. The results show that both the cell density and the specific growth rate of A.tamarense first increased when the N/P atomic ratio ≤ (N/P)opt and then decreased when the N/P atomic ratio ≥ (N/P)opt in low-P-grown cultures, followed by those in medium-P-grown and high-P-grown cultures. And the highest cell density in low-P-grown, medium-P-grown, and high-P-grown cultures is 1776×104, 4094×104 and 6891×104 cells/L, respectively. The maximum specific growth rate is 4.022, 5.307 and 9.672 d-1, respectively. It seems that the higher the initial phosphate concentrations, the greater the probability of red tide outbreaks.

scholarly journals Optimization of Culture Conditions on Growth of Chlorella sp. Newly Isolated From Bagansiapiapi Waters Indonesia

2021 ◽  
Vol 934 (1) ◽  
pp. 012097
Author(s):  
D Iriani ◽  
B Hasan ◽  
HS Putra ◽  
TM Ghazali
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Cell Density ◽  
Specific Growth ◽  
Pharmaceutical Products ◽  
Culture Conditions ◽  
Marine Waters ◽  
Chlorella Sp ◽  
Need To Evaluate ◽  
Further Development

Abstract Chlorella sp. is a type of micro-sized green algae obtained in fresh or marine waters. However, many factors need to evaluate the growth of Chlorella sp. mainly the culture conditions. This study aimed to evaluate the culture conditions in optimizing the growth of Chlorella sp. newly isolated from Bagansiapiapi marine waters. The experiment was carried out at temperature ±25°C, light intensity 2300 Lux using TL-D lamp (36 W). There were six treatments as culture conditions for the cultivation of Chlorella sp.:1). Bean Sprouts (Vigna radiata) Extract Media (BSEM) with light continuously, 2. BSEM with a Photoperiod light:dark (10:14h), 3. Tofu waste media with light continuously, 4. Tofu waste media with a photoperiod light:dark (10: 14h), 5. Fish pellet solutions media (25%), 6. Fish pellet solutions media (50%). The parameter observed was the growth, cell density and the specific growth rate of Chlorella sp. every 2 days for 14 days of cultivation. Based on the results shown that the marine Chlorella sp. from Bagansiapiapi waters could be adapted to all treatments. Nevertheless, the use of BSEM light continuously obtained the highest cell density (27.75 x 105 cell/ml) on 12 days and continues to increase until 14 days, while the other treatments had decreased. Furthermore, the Chlorella sp. obtained the specific growth rate was 0.42. Therefore, the marine Chlorella sp. from Bagansiapiapi could be cultivated in BSEM light continuously for further development as a functional food or bioactive source in pharmaceutical products.

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