scholarly journals Effects of Different Concentrations of Nitrogen and Phosphate on Growth of Sargassum thunbergii Germlings (Phaephyta)

2016 ◽  
Vol 4 (2) ◽  
pp. 1
Author(s):  
Zi Wang ◽  
Qingyun Yu ◽  
Haili Tan
Keyword(s):  
Growth Inhibition ◽  
Nutrient Concentrations ◽  
Sargassum Thunbergii ◽  
Nutrient Condition ◽  
Adverse Conditions ◽  
N:P Ratios ◽  
Group I

In the present study, the germlings shortly released from fertile thalli of <em>S. thunbergii</em> were collected and cultured in the laboratory. The stress resistances of germlings to adverse conditions of different nutrient concentrations and N:P ratios on growth of germingling sporophyte and rizoids were analyzed. Results showed that different concentrations of nitrogen and phosphate could significanly affect the relative grwoth rate and the most obvious growth inhibition was observed in group I which stood for the heavily eutrophicated nutrient condition. Moreover, the negative nutrient condition exerted more serious inhibition on germling sporophyte compared to that on the rizoid, and this might be a suvival strategy for the sustainability of <em>S. thunbergii</em> population.

scholarly journals A macro-tidal freshwater ecosystem recovering from hypereutrophication: the Schelde case study

2009 ◽  
Vol 6 (12) ◽  
pp. 2935-2948 ◽  
Author(s):  
T. J. S. Cox ◽  
T. Maris ◽  
K. Soetaert ◽  
D. J. Conley ◽  
S. Van Damme ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Algal Biomass ◽  
Alternative Stable States ◽  
Algal Growth ◽  
Nutrient Concentrations ◽  
Freshwater Ecosystem ◽  
Nutrient Inputs ◽  
Stable States ◽  
Estuarine Ecosystem ◽  
Algal Growth Inhibition

Abstract. We report a 40 year record of eutrophication and hypoxia on an estuarine ecosystem and its recovery from hypereutrophication. After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observe a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs. We hypothesise that algal growth was inhibited due to hypereutrophication, either by elevated ammonium concentrations, severe hypoxia or the production of harmful substances in such a reduced environment. We study the dynamics of a simple but realistic mathematical model, incorporating the assumption of algal growth inhibition. It shows a high algal biomass, net oxygen production equilibrium with low ammonia inputs, and a low algal biomass, net oxygen consumption equilibrium with high ammonia inputs. At intermediate ammonia inputs it displays two alternative stable states. Although not intentional, the numerical output of this model corresponds to observations, giving extra support for assumption of algal growth inhibition. Due to potential algal growth inhibition, the recovery of hypereutrophied systems towards a classical eutrophied state, will need reduction of waste loads below certain thresholds and will be accompanied by large fluctuations in oxygen concentrations. We conclude that also flow-through systems, heavily influenced by external forcings which partly mask internal system dynamics, can display multiple stable states.

scholarly journals Contribution of Soil and Litter Nutrient Characteristics to Plant Nutrients in a Natural Secondary Mixed Forest in the Qinling Mountains, China

2021 ◽  
Author(s):  
Yue Pang ◽  
Jing Tian ◽  
Lanxin Liu ◽  
Lina Han ◽  
Dexiang Wang
Keyword(s):  
Plant Growth ◽  
Mixed Forest ◽  
Woody Species ◽  
Plant Functional Groups ◽  
Nutrient Concentrations ◽  
Functional Difference ◽  
Qinling Mountains ◽  
Study Region ◽  
Plant Organs ◽  
N:P Ratios

Abstract Soil and litter play important roles in ecosystem nutrient stroage and cycling, which both affect plant growth and ecosystem productivity. However, the potential contributions of soil and litter nutrient characteristics to the nutrient characteristics of different plant functional groups (PFGs) remain unclear. In this study, we investigated the carbon (C), nitrogen (N) and phosphorus (P) concentrations of different organs of three PFGs (trees, shrubs and herbs), litter and soil in nine natural secondary mixed forests in the Qinling Mountains. The results showed that leaves had the highest N and P concentrations and N:P ratios at the organ level, whereas the C:N and C:P values were lowest in leaves. At the PFG level, the N and P concentrations of the same organs in herbaceous plants were significantly higher than those in woody species, while the N:P ratio was significantly lower in herb leaves than in tree and shrub leaves. Tree organs had significantly higher C concentrations and C:N and C:P ratios than shrub and herb organs. The leaf N:P ratios of all PFGs were less than 14, suggested that plant growth was limited by N in the study region. The nutrient contents and stoichiometric ratios in plant organs had different degrees of linkages with those in litter and soil. Soil nutrient characteristics were the main factors affecting the nutrient characteristics of the different PFGs, and litter nutrient characteristics also had important contributions to the nutrient characteristics of PFGs, showing the following order: herbs > trees > shrubs. Our results indicate that the functional difference in plant organs resulted in diverse nutrient concentrations; and varied nutrient connections exist among different ecosystem components. Furthermore, nutrient characteristics of litter and soil can together affect the nutrient characteristics of PFGs.

Increased Juvenile Salmonid Growth by Whole-River Fertilization

1990 ◽  
Vol 47 (5) ◽  
pp. 862-872 ◽  
Author(s):  
N. T. Johnston ◽  
C J. Perrin ◽  
P. A. Slaney ◽  
B. R. Ward
Keyword(s):  
Primary Production ◽  
Standing Crop ◽  
Coho Salmon ◽  
Inorganic Phosphorus ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Steelhead Trout ◽  
Artificial Substrata ◽  
N:P Ratios ◽  
Coastal Streams

Nutrient concentrations, periphyton standing crop and size of steelhead trout (Oncorhynchus mykiss) and coho salmon (O, kisutch) fry increased after the fertilization of a nutrient-deficient stream with inorganic phosphorus (P) and nitrogen (N). Whole-river fertilization of the Keogh River, British Columbia, during 1983–86 to increase summer average nutrient concentrations from < 1 μg P∙L−1 and 25 μg N∙L−1 to 10–15 μg P∙L−1 and 30–100 μg N∙L−1 resulted in five- to 10-fold increases in periphyton standing crops on artificial substrata and 1.4- to 2.0-fold increases in late-September salmonid fry weights. Diatoms and chlorophytes dominated the algal periphyton on artificial substrata at fertilized sites. Cyanophytes were unimportant despite low N:P ratios in some cases. Juvenile salmonids fed primarily on benthic insects. These results suggest that autochthonous primary production can be an important energy source in forested, middle-order streams, and indicate that the manipulation of autochthonous primary production can be a useful management tool to increase salmonid growth in nutrient-poor coastal streams.

Mass, nutrient content, and decay rate of dead boles in rain forests of Olympic National Park

1982 ◽  
Vol 12 (3) ◽  
pp. 511-521 ◽  
Author(s):  
Robin Lambert Graham ◽  
Kermit Cromack. Jr.
Keyword(s):  
National Park ◽  
Nutrient Content ◽  
Nutrient Concentrations ◽  
Forest Types ◽  
Olympic Peninsula ◽  
Olympic National Park ◽  
N:P Ratios ◽  
Open Forest ◽  
Closed Forest ◽  
Closed Canopy

Analysis of dead boles of Piceasitchensis (Bong.) Carr. and Tsugaheterophylla (Raf.) Sarg. in open- and closed-canopy forests of the Olympic Peninsula Washington, U.S.A., revealed that hemlock mortality in both forest types was due mainly to windthrow, whereas spruce typically died upright. The open forest contained 120 t/ha of dead bole wood; the closed forest contained 161 t/ha. Hemlock boles decayed more rapidly than the larger spruce boles, although both showed considerable variability. On a per-hectare basis, 146–223 kg of N, 147–197 kg of Ca. 39–61 kg of K, 18–29 kg of Mg, 6–14 kg of Na, and 17–29 kg of P were contained in dead boles of the open- and closed-canopy forests, respectively. Except for N and Mg, the nutrient concentrations of the wood were not significantly different after 33–68 years of bole decay. The N:P ratios increased with increasing decay for both species.

scholarly journals Effects of Nutrient Content and Nitrogen to Phosphorous Ratio on the Growth, Nutrient Removal and Desalination Properties of the Green Alga Coelastrum morus on a Laboratory Scale

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2112
Author(s):  
Aida Figler ◽  
Kamilla Márton ◽  
Viktória B-Béres ◽  
István Bácsi
Keyword(s):  
Green Alga ◽  
Nutrient Removal ◽  
Algal Species ◽  
Nutrient Content ◽  
N:P Ratio ◽  
Phosphate Removal ◽  
Nutrient Concentrations ◽  
Nitrate Content ◽  
Green Algal ◽  
N:P Ratios

In wastewater, nutrient concentrations and salinity vary substantially, however, the optimal N:P ratio for the treatment using microalgae is not well described. In this study, the effects of higher and lower nitrate and phosphate contents and N:P ratios on growth, nutrient removal ability and halotolerance of the common green alga Coelastrum morus were investigated in model solutions. The results suggest that high nitrate content (above 100 mg L−1) with a similarly high phosphate concentration (resulting low N:P ratio) is not favorable for growth. The studied isolate can be considered as a halotolerant species, showing remarkable growth up to 1000 mg L−1 NaCl and it seems that despite the negative effects on growth, higher nutrient content contributes to higher halotolerance. A significant amount of nitrate removal was observed in media with different nutrient contents and N:P ratios with different salt concentrations. High N:P ratios favor phosphate removal, which is more inhibited by increasing NaCl concentration than nitrate uptake. Overall, with a relatively higher nutrient content and a favorable (5 or higher) N:P ratio, a common green algal species such as C. morus could be a promising candidate next to species from the Chlorellaceae and Scenedesmaceae families.

scholarly journals Growth inhibition of Walker carcinosarcoma 256 with alcoholic extract of green tea leaves (Camellia sinensis)

2012 ◽  
Vol 27 (9) ◽  
pp. 634-638 ◽  
Author(s):  
Mauriclécio Franco Ponte ◽  
Thiago Sousa e Silva Targino ◽  
Matheus Alves de Lima Mota ◽  
José Saul Peixoto Landim ◽  
Thyciana Rodrigues Ribeiro ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Growth Inhibition ◽  
Green Tea ◽  
Tumor Volume ◽  
Group Iv ◽  
Tumor Growth Inhibition ◽  
Alcoholic Extract ◽  
Control Solution ◽  
Group I ◽  
Group Ii

PURPOSE: To evaluate the antitumor activity of alcoholic extracts of green tea (Camella sinensis). METHODS: Four groups of six Wistar rats were inoculated intramuscularly with 10(6) Walker tumor cells/mL. During 10 days, the animals received by gavage either 0.9% saline solution (Group I; negative control), solution containing 20 mg/Kg of tamoxifen (Group II; positive control), solution containing 0.07 g/Kg alcoholic extract of C. sinensis (Group III), or solution containing 0.14 g/Kg alcoholic extract of C. sinensis (Group IV). Following euthanasia on the tenth day, the tumor, liver, kidneys and spleen were excised and weighed, and tumor volume and tumor growth inhibition were quantified. RESULTS: The average weight of the animals was greater in Group IV than in Group II (p=0.0107). Tumor weight was smaller in Group IV than in Group I (p=0.0062), but did not differ from Group II. Tumor volume was smaller in Groups II and IV than in Group I (p=0.0131). Tumor growth inhibition was observed in Groups II (44.67% ± 32.47), III (16.83% ± 53.02) and IV (66.4% ± 25.82) (p>0.05). The groups did not differ with regard to the weight of the excised organs. CONCLUSION: Alcoholic extracts of green tea have antitumor activity.

scholarly journals Pentamidine Inhibition of Group I Intron Splicing in Candida albicans Correlates with Growth Inhibition

2000 ◽  
Vol 44 (4) ◽  
pp. 958-966 ◽  
Author(s):  
Karl E. Miletti ◽  
Michael J. Leibowitz
Keyword(s):  
Candida Albicans ◽  
Growth Inhibition ◽  
Pneumocystis Carinii ◽  
Group I Intron ◽  
Rrna Genes ◽  
Broth Microdilution ◽  
Reverse Transcription Pcr ◽  
Group I ◽  
Rrna Maturation

ABSTRACT We previously demonstrated that pentamidine, which has been clinically used against Pneumocystis carinii, inhibits in vitro a group I intron ribozyme from that organism. Another fungal pathogen, Candida albicans, also harbors a group I intron ribozyme (Ca.LSU) in the essential rRNA genes in almost half of the clinical isolates analyzed. To determine whether pentamidine inhibits Ca.LSU in vitro and in cells, phylogenetically closely related intron-containing (4-1) and intronless (62-1) strains were studied. Splicing in vitro of the Ca.LSU group I intron ribozyme was completely inhibited by pentamidine at 200 μM. On rich glucose medium, the intron-containing strain was more sensitive to growth inhibition by pentamidine than was the intronless strain, as measured by disk or broth microdilution assays. On rich glycerol medium, they were equally susceptible to pentamidine. At pentamidine levels selectively inhibiting the intron-containing strain (1 μM) in glucose liquid cultures, inhibition of splicing and rRNA maturation was detected by quantitative reverse transcription-PCR within 1 min with a 10- to 15-fold accumulation of precursor rRNA. No comparable effect was seen in the intronless strain. These results correlate the cellular splicing inhibition of Ca.LSU with the growth inhibition of strain 4-1 harboring Ca.LSU. Broth microdilution assays of 13 Candida strains showed that intron-containing strains were generally more susceptible to pentamidine than the intronless strains. Our data suggest that ribozymes found in pathogenic microorganisms but absent in mammals may be targets for antimicrobial therapy.

scholarly journals Overexpression of PrfA Leads to Growth Inhibition of Listeria monocytogenes in Glucose-Containing Culture Media by Interfering with Glucose Uptake

2006 ◽  
Vol 188 (11) ◽  
pp. 3887-3901 ◽  
Author(s):  
A. K. Marr ◽  
B. Joseph ◽  
S. Mertins ◽  
R. Ecke ◽  
S. Müller-Altrock ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Inhibition ◽  
Glucose Uptake ◽  
Nitrogen Metabolism ◽  
Culture Media ◽  
Phosphotransferase System ◽  
Group Iii ◽  
Group I ◽  
Multiple Copies ◽  
Overexpressing Strain

ABSTRACT Listeria monocytogenes strains expressing high levels of the virulence regulator PrfA (mutant PrfA* or wild-type PrfA) show strong growth inhibition in minimal media when they are supplemented with glucose but not when they are supplemented with glucose-6-phosphate compared to the growth of isogenic strains expressing low levels of PrfA. A significantly reduced rate of glucose uptake was observed in a PrfA*-overexpressing strain growing in LB supplemented with glucose. Comparative transcriptome analyses were performed with RNA isolated from a prfA mutant and an isogenic strain carrying multiple copies of prfA or prfA* on a plasmid. These analyses revealed that in addition to high transcriptional up-regulation of the known PrfA-regulated virulence genes (group I), there was less pronounced up-regulation of the expression of several phage and metabolic genes (group II) and there was strong down-regulation of several genes involved mainly in carbon and nitrogen metabolism in the PrfA*-overexpressing strain (group III). Among the latter genes are the nrgAB, gltAB, and glnRA operons (involved in nitrogen metabolism), the ilvB operon (involved in biosynthesis of the branched-chain amino acids), and genes for some ABC transporters. Most of the down-regulated genes have been shown previously to belong to a class of genes in Bacillus subtilis whose expression is negatively affected by impaired glucose uptake. Our results lead to the conclusion that excess PrfA (or PrfA*) interferes with a component(s) essential for phosphotransferase system-mediated glucose transport.

Ultrastructural Lesions Produced by Alcohol and Sucrose in the Heart and Liver of C57BL Mice

1970 ◽  
Vol 28 ◽  
pp. 208-209
Author(s):  
K.K. SEKHRI ◽  
C.S. ALEXANDER ◽  
H.T. NAGASAWA
Keyword(s):  
Osmium Tetroxide ◽  
Male Mice ◽  
Alcohol Group ◽  
Group Iii ◽  
Group I ◽  
C57bl Mice ◽  
Group Ii

C57BL male mice (Jackson Lab., Bar Harbor, Maine) weighing about 18 gms were randomly divided into three groups: group I was fed sweetened liquid alcohol diet (modified Schenkl) in which 36% of the calories were derived from alcohol; group II was maintained on a similar diet but alcohol was isocalorically substituted by sucrose; group III was fed regular mouse chow ad lib for five months. Liver and heart tissues were fixed in 2.5% cacodylate buffered glutaraldehyde, post-fixed in 2% osmium tetroxide and embedded in Epon-araldite.

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