Effects of Ca2+ on the growth of Dunaliella tertiolecta in media with high concentrations of Mg2+

1992 ◽  
Vol 70 (7) ◽  
pp. 1331-1335 ◽  
Author(s):  
Shuhei Fujii ◽  
Johan A. Hellebust

The growth rate of Dunaliella tertiolecta in a high MgSO4 (0.94 M) medium was lower than that in a NaCl medium of the same osmolality. Growth inhibition of D. tertiolecta in the high MgSO4 medium was partially relieved in response to increases in extracellular Ca2+ concentrations (1 – 11 mM). This growth recovery effect by supplemental Ca2+ was eliminated by the simultaneous additions of ethylene glycol-bis-(β-aminoethyl ether)-N′,N′-tetraacetic acid. The measurements of intracellular cations revealed that the intracellular concentration of Ca2+ increased with increases in the extracellular Ca2+ concentration. From the kinetic analysis of the relationship between the extracellular Ca2+ concentration and the growth in media containing various concentrations of Mg2+, Ca2+ was found to interact competitively with Mg2+ with regard to growth of D. tertiolecta in MgSO4 media. These results indicate that high concentrations of Mg2+ inhibit the uptake of Ca2+ into cells, resulting in the observed growth inhibition in MgSO4 media. Key words: Dunaliella, magnesium, calcium, antagonistic effect.

1939 ◽  
Vol 16 (2) ◽  
pp. 232-249
Author(s):  
C. M. POMERAT ◽  
E. N. WILLMER

1. Growth of chick periosteal fibroblasts is inhibited by 0.002 M solutions of glyceraldehyde, benzaldehyde, butyl aldehyde, propyl aldehyde and methyl glyoxal. 2. The growth is not inhibited by sodium pyruvate, lactate, propionate, glycerate or benzoate. 3. Sodium pyruvate does not affect the growth under the conditions of the experiments, nor does it alter the inhibition brought about by glyceraldehyde. 4. Growth is inhibited by sodium fluoride and sodium iodoacetate in the concentrations in which these inhibit glucolysis. Growth inhibition does not correspond to inhibition of phosphorylation. 5. Growth is not inhibited by 0.008 M phlorizin. 6. Growth is not immediately inhibited by an atmosphere containing 95% CO and 5% O2. 7. Growth is not immediately inhibited by 0.002 M sodium azide, 0.002 M HCN or by 0.01 M sodium malonate. Azide and cyanide reduce the growth rate after some hours. 8. Growth is not accelerated by the addition of 0.006 M sodium fumarate. 9. Growth is inhibited by 0.01 M sodium ferricyanide. 10. The relationship between carbohydrate metabolism and growth by cell division is discussed in the light of these results.


2018 ◽  
Vol 24 (3) ◽  
pp. 341-358 ◽  
Author(s):  
Xiaotong Ji ◽  
Yingying Zhang ◽  
Guangke Li ◽  
Nan Sang

Recently, numerous studies have found that particulate matter (PM) exposure is correlated with increased hospitalization and mortality from heart failure (HF). In addition to problems with circulation, HF patients often display high expression of cytokines in the failing heart. Thus, as a recurring heart problem, HF is thought to be a disorder characterized in part by the inflammatory response. In this review, we intend to discuss the relationship between PM exposure and HF that is based on inflammatory mechanism and to provide a comprehensive, updated evaluation of the related studies. Epidemiological studies on PM-induced heart diseases are focused on high concentrations of PM, high pollutant load exposure in winter, or susceptible groups with heart diseases, etc. Furthermore, it appears that the relationship between fine or ultrafine PM and HF is stronger than that between HF and coarse PM. However, fewer studies paid attention to PM components. As for experimental studies, it is worth noting that coarse PM may indirectly promote the inflammatory response in the heart through systematic circulation of cytokines produced primarily in the lungs, while ultrafine PM and its components can enter circulation and further induce inflammation directly in the heart. In terms of PM exposure and enhanced inflammation during the pathogenesis of HF, this article reviews the following mechanisms: hemodynamics, oxidative stress, Toll-like receptors (TLRs) and epigenetic regulation. However, many problems are still unsolved, and future work will be needed to clarify the complex biologic mechanisms and to identify the specific components of PM responsible for adverse effects on heart health.


2006 ◽  
Vol 25 (5) ◽  
pp. 243-250 ◽  
Author(s):  
M S Allagui ◽  
N Hfaiedh ◽  
C Vincent ◽  
F Guermazi ◽  
J-C Murat ◽  
...  

Lithium therapy, mainly used in curing some psychiatric diseases, is responsible for numerous undesirable side effects. The present study is a contribution to the understanding of the pathophysiological mechanisms underlying lithium toxicity. Male and female mature rats were divided into three batches and fed commercial pellets: one batch was the control and the second and third batches were given 2 g (Li1) and 4 g (Li2) of lithium carbonate/kg of food/day, respectively. After 7, 14, 21 and 28 days, serum levels of free tri-iodothyronine (FT3), thyroxine (FT4), testosterone and estradiol were measured. Attention was also paid to growth rate and a histological examination of testes or vaginal mucosa was carried out. In treated rats, a dose-dependent loss of appetite and a decrease in growth rate were observed, together with symptoms of polydypsia, polyuria and diarrhea. Lithium serum concentrations increased from 0.44 mM (day 7) to 1.34 mM (day 28) in Li1 rats and from 0.66 to 1.45 mM (day 14) in Li2 rats. Li2 treatment induced a high mortality after 14 days, reaching 50-60% in female and male animals. From these data, the LD50 (14 days Li2 chronic treatment) was calculated to be about 0.3 g/day per kilogram of animal, leading to Li serum concentrations of about 1.4 mM. A significant decrease of FT3 and FT4 was observed in treated rats. This effect appeared immediately for the highest dose and was more pronounced for FT3, resulting in an increase of the FT4/FT3 ratio. In males, testosterone decreased and spermatogenesis was stopped. Conversely, in females, estradiol increased in a dose-dependent manner as the animals were blocked in the diestrus phase at day 28. This finding supports a possible antagonistic effect of lithium on the estradiol receptors.


2021 ◽  
Vol 9 (5) ◽  
pp. 474
Author(s):  
René Rodríguez-Grimón ◽  
Nestor Hernando Campos ◽  
Ítalo Braga Castro

Since 2013, there has been an increase (>23%) in naval traffic using maritime routes and ports on the coastal fringe of Santa Marta, Colombia. Of major concern, and described by several studies, is the relationship between maritime traffic and coastal contamination. This study proposed a maritime traffic indicator considering the simultaneous effects of several relevant measurements of water quality parameters to estimate the impact of naval activity. The approach involved developing a model including the number of vessels, hull length, and permanence time in berths. In addition, water quality variables, considering climatic seasons, were used to verify association with maritime traffic and touristic activities. The high concentrations of total coliforms (TC) and dissolved/dispersed petroleum hydrocarbons in chrysene equivalents (DDPH) reported by the International Marina of Santa Marta (SM) were affected by the local anthropic activities, including tourism, naval traffic, and urban wastewater discharges. Moreover, our results suggest the occurrence of multiple chemical impacts within Tayrona National Natural Park (PNNT) affecting conservation goals. The estimation of the maritime traffic indicator proposed in this study may be an easy and more complete tool for future studies evaluating the impact of naval activities on environmental quality.


2021 ◽  
Vol 64 (1) ◽  
pp. 13-18
Author(s):  
Ira Gray ◽  
Lindsay A. Green-Gavrielidis ◽  
Carol Thornber

Abstract Caffeine is present in coastal environments worldwide and there is a need to assess its impact on marine organisms. Here, we exposed two species of ecologically important marine macroalgae (Chondrus crispus and Codium fragile subsp. fragile) to a suite of caffeine concentrations and measured their response. Caffeine concentrations of 10–100 ng L−1 had no significant effect on the growth rate or photosynthetic efficiency of either algae. Extremely high concentrations (100–200 mg L−1), which may occur acutely, produced sublethal effects for both species and mortality in C. fragile subsp. fragile. Our results highlight the need to understand how caffeine impacts marine species.


Urban Studies ◽  
2021 ◽  
pp. 004209802110060
Author(s):  
Christophe Leclerc ◽  
Maarten Vink ◽  
Hans Schmeets

Whereas the so-called ‘citizenship premium’ in the labour market has been widely studied, we know little about how naturalisation affects immigrants’ lives beyond work and income. Focusing on the Netherlands, this paper analyses the relationship between citizenship acquisition and immigrant residential mobility, in particular the propensity of immigrants to move away from areas with high concentrations of migrants. We draw on register data from Statistics Netherlands ( N = 234,912). We argue that possessing Dutch citizenship reduces spatial stratification by diminishing the risk of housing market discrimination, thereby facilitating mobility outside of migrant-concentrated areas. Our findings show that naturalised immigrants are 50% more likely to move out of concentrated neighbourhoods, all else constant. The effect of naturalisation is especially relevant for renting without housing benefits and for home ownership, and for mid-risk immigrants who earn around the median income and hold permanent jobs, whose applications face strong scrutiny from landlords, rental agencies and mortgage lenders.


2011 ◽  
Vol 56 (No. 5) ◽  
pp. 242-249 ◽  
Author(s):  
Z. Ledvinka ◽  
L. Zita ◽  
M. Hubený ◽  
E. Tůmová ◽  
M. Tyller ◽  
...  

We assessed the influence of the particular genotype, age of layers, feather growth-rate gene, and their mutual interactions on selected indicators of eggshell quality in six groups of hens of the laying type Dominant. The following genotypes were examined in the experiment: Barred Plymouth Rock, Dominant BPR 951 (K) strain, slow-feathering; Barred Plymouth Rock, Dominant BPR 901 (k) strain, fast-feathering; Blue Plymouth Rock, Dominant BLPR 954 (K) strain, slow-feathering; Blue Plymouth Rock, Dominant BLPR 894 (k) strain, fast-feathering; crossbreds of the above strains in the F<sub>1</sub> generation Dominant D 107 blue (K), slow-feathering and Dominant D 107 blue (k), fast-feathering. The layers were fed a feed mixture NP1 (16.64 % CP) from the 20<sup>th</sup> week of age and a feed mixture NP2 (15.02% CP) from the 42<sup>nd</sup> week. Husbandry conditions met the regular requirements of laying hens. Egg production and live weight of hens were monitored for the duration of the experiment (12 months). Eggshell quality was examined at the layers' age of 27, 35 and 56 weeks. The average hen-day egg production for the duration of the experiment (12 months) was not significantly influenced by the particular genotype or the feather growth-rate gene. The varying representation of the feather growth-rate gene significantly (P &le; 0.001) influenced the live weight; similarly, the relationship between the genotype and the representation of K/k alleles was significant. The average egg weight was influenced statistically significantly (P &le; 0.001) by the age of hens, their genotype (P &le; 0.05), feather growth-rate gene (P &le; 0.001), and the relationship between the age and genotype (P &le; 0.001). The age of hens, genotype, and the interaction of these two factors affected the egg shape index, as did the incidence of the feather growth-rate gene within the population (with a statistical significance of P &le; 0.001). The age, genotype and the feather growth-rate gene incidence within the population also significantly affected the eggshell quality indicators. In the eggshell to egg ratio, eggshell thickness and strength, an interaction was determined between the age of hens and their particular genotype. The eggshell colour was also significantly (P &le; 0.001) affected by hens' age, genotype (P &le; 0.001), as well as by the feather growth-rate gene (P &le; 0.001). No significant interaction between the age and the genotype was found for this indicator.


2009 ◽  
Vol 13 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Yi Jin

This paper develops a monetary endogenous growth model with capital and skill heterogeneity to analyze the relationship among inflation, growth, and income inequality. In the model inflation, growth, and inequality are jointly determined. We show that an increase in the long-run money growth rate raises inflation and reduces growth, but its effect on income inequality depends on the relative importance of the two types of heterogeneity. Inequality shrinks with the rise of inflation when capital heterogeneity dominates and enlarges when skill heterogeneity dominates. Therefore, our model supports a negative (positive) inflation–inequality relationship and a positive (negative) growth–inequality relationship when capital (skill) heterogeneity dominates. In any event, inflation and growth are negatively related.


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