Effects of pH on the growth rate, motility and photosynthesis inEuglena gracilis

2001 ◽  
Vol 46 (6) ◽  
pp. 549-554 ◽  
Author(s):  
R. A. Danilov ◽  
N. G. A. Ekelund
Keyword(s):  
Growth Rate ◽  
Effects Of Ph

scholarly journals Combined Effects of pH and Sugar on Growth Rate ofZygosaccharomyces rouxii, a Bakery Product Spoilage Yeast

1999 ◽  
Vol 65 (11) ◽  
pp. 4921-4925 ◽  
Author(s):  
Jeanne-Marie Membré ◽  
Martine Kubaczka ◽  
Christine Chéné
Keyword(s):  
Growth Rate ◽  
Synthetic Medium ◽  
Growth Curves ◽  
Estimated Parameters ◽  
Spoilage Yeast ◽  
Effects Of Ph ◽  
Biological Interpretation ◽  
Collection Strain ◽  
Ph Range ◽  
Counting Cell

ABSTRACT The effects of citric acid-modified pH (pH 2.5, 2.75, 3, 3.5, 4, 4.5, 5, and 5.5) and a 30% glucose–70% sucrose mixture (300, 400, 500, 600, 700, 800, 875, and 900 g/liter) on an osmophilic yeast,Zygosaccharomyces rouxii, were determined by using synthetic medium. One hundred experiments were carried out; 50-ml culture flasks were inoculated with 103 CFU ml−1 by using a collection strain and a wild-type strain cocktail. The biomass was measured by counting cell colonies, and growth curves were fitted by using a Baranyi equation. The growth rate decreased linearly with sugar concentration, while the effect of pH was nonlinear. Indeed, the optimal pH range was found to be pH 3.5 to 5, and pH 2.5 resulted in a 30% reduction in the growth rate. Finally, we evaluated the performance of two nonlinear predictive models developed previously to describe bacterial contamination. Equations derived from the Rosso and Ratkowsky models gave similar results; however, the model that included dimensionless terms based on the Ratkowsky equation was preferred because it contained fewer estimated parameters and also because biological interpretation of the results was easier.

scholarly journals Effects of pH, temperature and light intensity on spore germination and growth analysis of young sporophytes of Polypodium lepidopteris (Pteridophyta, Polypodiaceae)

Rodriguésia ◽  
2008 ◽  
Vol 59 (4) ◽  
pp. 751-760 ◽  
Author(s):  
Daniela Viviani ◽  
Áurea Maria Randi
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Spore Germination ◽  
Coastal Vegetation ◽  
Natural Light ◽  
Relative Growth ◽  
Light Levels ◽  
Effects Of Ph ◽  
Spore Inoculation ◽  
Young Sporophytes

ABSTRACT Polypodium lepidopteris is a terrestrial fern from coastal vegetation, and is used as medicinal. This work analyzed the effects of pH, temperature and light levels on the spore germination and the relative growth rate (RGR) of young sporophytes. Fertile fronds were collected in Florianópolis, SC, Brazil. The effect of pH (4.0 to 6.7) on spore germinability was observed in a growing room at 25 ± 2ºC (22 mmol m-2s-1) under a 16h photoperiod. No statistical differences between treatments were found. The effect of different temperatures on the germinability was analyzed (20, 25 and 30ºC). The test was carried out in a germination chamber (17 mmol m-2s-1) under a 16h photoperiod. The germination was inhibited at 30ºC. The effect of natural light levels (54, 38, 22 and 8%) was analyzed. The highest germination percentages were verified at 22 and 8% of natural light. The growth analyses show statistical differences in the number of fronds and height of the longest frond between time 1 (283 days of spore inoculation) and time 2 (343 days of spore inoculation). Sporophytes of P. lepidopteris produced 1.33 ± 0.09 fronds per month. The RGR (relative growth rate) was 0.15 ± 0,009 cm cm-1month-1.

scholarly journals Effects of pH, Water Activity, Nitrite and Sorbic Acid on the Growth Rate of Listeria monocytogenes in Cooked Meat Products and Raw Ham

2012 ◽  
Vol 59 (4) ◽  
pp. 186-191
Author(s):  
Naoko Kamisaki-Horikoshi ◽  
Yukio Okada ◽  
Kazuko Takeshita ◽  
Takashi Sameshima ◽  
Keizo Arihara
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Water Activity ◽  
Sorbic Acid ◽  
Meat Products ◽  
Effects Of Ph ◽  
Cooked Meat ◽  
Cooked Meat Products

Effects of pH on the growth rate exhibited of the wild-type and Cd-resistant Dictyosphaerium chlorelloides strains

Limnetica ◽  
2018 ◽  
pp. 229-238
Author(s):  
Cortés, Alondra A. ◽  
Sánchez-Fortún, Sebastián ◽  
García, Martha ◽  
Bartolomé, Mª Carmen
Keyword(s):  
Growth Rate ◽  
Wild Type ◽  
Effects Of Ph ◽  
Dictyosphaerium Chlorelloides

Fibrous hydroxyapatite grown in the gel system: effects of pH of the solution on the growth rate and morphology

1992 ◽  
Vol 3 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Masami Tanahashi ◽  
Kanichi Kamiya ◽  
Tohru Suzuki ◽  
Hiroyuki Nasu
Keyword(s):  
Growth Rate ◽  
Effects Of Ph ◽  
Gel System

scholarly journals Effects of pH and Nutrients (Nitrogen) on Growth and Toxin Profile of the Ciguatera-Causing Dinoflagellate Gambierdiscus polynesiensis (Dinophyceae)

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 767
Author(s):  
Sébastien Longo ◽  
Manoëlla Sibat ◽  
Hélène Taiana Darius ◽  
Philipp Hess ◽  
Mireille Chinain
Keyword(s):  
Growth Rate ◽  
N:P Ratio ◽  
French Polynesia ◽  
Low Ph ◽  
Sea Surface ◽  
Coastal Eutrophication ◽  
N Source ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Effects Of Ph

Ciguatera poisoning is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. Ciguatera outbreaks are expected to increase worldwide with global change, in particular as a function of its main drivers, including changes in sea surface temperature, acidification, and coastal eutrophication. In French Polynesia, G. polynesiensis is regarded as the dominant source of CTXs entering the food web. The effects of pH (8.4, 8.2, and 7.9), Nitrogen:Phosphorus ratios (24N:1P vs. 48N:1P), and nitrogen source (nitrates vs. urea) on growth rate, biomass, CTX levels, and profiles were examined in four clones of G. polynesiensis at different culture age (D10, D21, and D30). Results highlight a decrease in growth rate and cellular biomass at low pH when urea is used as a N source. No significant effect of pH, N:P ratio, and N source on the overall CTX content was observed. Up to ten distinct analogs of Pacific ciguatoxins (P-CTXs) could be detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in clone NHA4 grown in urea, at D21. Amounts of more oxidized P-CTX analogs also increased under the lowest pH condition. These data provide interesting leads for the custom production of CTX standards.

scholarly journals Effects of pH on physiological parameters of blood and growth performance of Asian

2019 ◽  
Vol 18 (01) ◽  
pp. 89-97
Author(s):  
Tuan V. Vo
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Specific Growth Rate ◽  
Growth Performance ◽  
Specific Growth ◽  
Physiological Parameters ◽  
Water Levels ◽  
Daily Weight Gain ◽  
Effects Of Ph ◽  
Set Up

Effects of pH on blood physiological parameters and growth performance of Asian bumblebee catfish (Pseudomystus siamensis) were carried out in laboratory conditions. The experiment was set up in 8 weeks at different pH water levels. The results showed that the cumulative mortality of Asian bumblebee catfish (4 - 6 g/fish) in 24 hpi was 100% at pH = 11, 70.83% at pH = 10 and 62.5% at pH = 3. No mortality of fish was observed at pH = 4, 5, 6, 7, 8, 9 at 24 hpi. The high content of glucose was recorded in fish cultured in water with low (4.02 mmol/L at pH = 3) and high (3.22 mmol/L at pH = 10) pH levels. After 8 weeks of culture, the highest content of glucose was observed at pH = 8 (1.10 mmol/L). The daily weight gain and specific growth rate in weight of fish were 0.02 - 0.08 g/day and 0.35 - 0.99%/day, respectively. The daily length gain specific growth rate in length were 0.02 - 0.04 cm/day and 0.22 - 0.53%/day. The highest survival rate of fish was recorded at pH = 6 (95.96%) and the lowest survival rate of fish was recorded at pH = 8 (60%).

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