Interactive effect of ammonia and pH on viability and 14C-labeled exudation from fungal propagules

1984 ◽  
Vol 62 (6) ◽  
pp. 1220-1226 ◽  
Author(s):  
D. Chun ◽  
A. B. Filonow ◽  
J. L. Lockwood
Keyword(s):  
Interactive Effect ◽  
Macrophomina Phaseolina ◽  
Ammonia Concentration ◽  
Labeled Compounds ◽  
Short Term ◽  
Lethal Effects ◽  
High Ph ◽  
Fungal Propagules ◽  
Sparing Effect

The effect of ammonia on exudation and viability of 14C-labeled propagules of Cochliobolus victoriae, Cochliobolus sativus, and Macrophomina phaseolina was studied in a model fungistatic system with nutrient-independent or nutrient-dependent propagules or in soil amended with urea from which ammonia was generated. In soil, ammonia stimulated exudation of 14C-labeled compounds, but their metabolism by the soil microbiota was suppressed. Short-term exposures of a few hours in a model fungistatic system with high free ammonia concentrations (up to 10 000 mg/L) stimulated a burst of exudation which was usually associated with death of the propagules. Lower concentrations increased exudation less, but exudation tended to be maintained at a level greater than that in nontreated controls. Viability was reduced when the propagules were continuously exposed to long-term doses which were nonlethal for shorter durations. High pH by itself increased exudation, but it did not account for the greater exudation effected by ammonia, nor for its lethal effects. In a fixed-volume system, which imposed low nutrient stress, ammonia (10–100 mg/L) had a sparing effect on the increased exudation brought on by high pH alone; as ammonia concentration was increased (100–1000 mg/L), the sparing effect was lost and exudation increased, accompanied by decreased viability.

Response mechanism of denitrifying anaerobic methane oxidation microorganisms to ammonia

2020 ◽  
Vol 17 (1) ◽  
pp. 17 ◽  
Author(s):  
Juqing Lou ◽  
Jiaping Li ◽  
Xilei Wang
Keyword(s):  
Methane Oxidation ◽  
Nitrogen Removal ◽  
Experimental Studies ◽  
Ammonia Concentration ◽  
Anaerobic Methane Oxidation ◽  
Limiting Factor ◽  
Response Mechanism ◽  
Short Term ◽  
Damo Bacteria

Environmental contextDenitrifying anaerobic methane oxidation (DAMO) is a new process in wastewater treatment with the potential to provide cheap and sustainable development. To better apply this technology to the large scale, we studied the response mechanism of DAMO microorganisms to ammonia, the main form of nitrogen in the nitrogenous wastewater. The results can provide a theoretical basis for the stable and efficient operation of DAMO processes. AbstractThe dominant microorganisms in the denitrifying anaerobic methane oxidation (DAMO) process are primarily DAMO bacteria and DAMO archaea, which can simultaneously realise methane oxidation and denitrification. Ammonia is the primary form of nitrogen found in wastewater. This study focuses on a coexistence system that contains both DAMO bacteria and DAMO archaea (DAMO co-system). The short- and long-term effects of NH4+-N on the DAMO co-system were investigated at both the macro level (such as denitrification performance) and the micro level (such as microbial structure and community). Short-term experimental studies demonstrated that the safe concentration of ammonia for this system was 250mgNL−1. When the ammonia concentration was 500mgNL−1, the nitrogen removal efficiency was significantly inhibited. With an increase in concentration and an extension of time, the inhibitory effect of ammonia was enhanced. Long-term experimental studies showed that the nitrogen removal performance of DAMO was completely inhibited when the ammonia concentration reached 1000mgNL−1 and that ammonia had a toxic accumulation effect on the DAMO co-system. The results of the pH experimental study demonstrated that free ammonia (FA) was the limiting factor in the alkaline condition, while ionised NH4+ was the limiting factor in neutral and acidic conditions. Scanning electron microscopy (SEM) demonstrated that the microbes in the DAMO co-system shrank after short-term exposure and that the microorganisms shrank in the shape of polygons. High-throughput sequencing analysis demonstrated that the community structure of the DAMO co-system changed substantially, and the species diversity and abundance decreased distinctly after long-term inhibition. A genus analysis indicated that the reduction in Nitrospirae may be an internal reason for the decrease in the denitrification performance of the DAMO co-system.

Short-term and long-term storage stability of heparin plasma ammonia

2015 ◽  
Vol 68 (4) ◽  
pp. 288-291 ◽  
Author(s):  
Lora Dukic ◽  
Ana-Maria Simundic
Keyword(s):  
Ammonia Concentration ◽  
Plasma Samples ◽  
Stability Assessment ◽  
Short Term ◽  
Initial Testing ◽  
Term Stability ◽  
C Storage ◽  
Long Term Storage ◽  
Heparin Plasma

AimsAmmonia is an extremely unstable analyte and requires special attention during sampling, transport and storage. The aim of this study was to evaluate the stability of ammonia in lithium-heparin plasma during short-term (at +4°C) and long-term (at −20°C) storage.MethodsTwenty plasma samples were used for short-term stability assessment. Each sample was divided into five aliquots and stored in stoppered tubes at +4°C, for 1, 2, 3, 4 and 24 h from initial testing. Fifteen plasma samples were used for long-term stability assessment. Each sample was divided into eight aliquots and stored in stoppered tubes at −20°C for 3, 24, 48 h and 1, 2, 4, 8 and 12 weeks from initial testing. Ammonia concentration was determined on a Beckman Coulter AU2700 chemistry analyser using Randox ammonia enzymatic UV method. Bias was calculated from initial value for each time point and compared with quality specifications defined by Royal College of Pathologists of Australasia.ResultsThe average bias exceeded the total allowable error after storage of samples for 1 h at +4°C and 3 h at −20°C.ConclusionAmmonia is not stable during storage at +4°C and −20°C in lithium-heparinised plasma and should therefore be analysed immediately.

scholarly journals The interactive effect of herbivory, nutrient enrichment and mucilage on shallow rocky macroalgal communities

2018 ◽  
Author(s):  
Sarah Caronni ◽  
Chiara Calabretti ◽  
Giulia Ceccherelli ◽  
Sandra Citterio ◽  
Maria Anna Delaria ◽  
...  
Keyword(s):  
Marine Protected Area ◽  
Interactive Effect ◽  
Term Effect ◽  
Short Term ◽  
Manipulative Experiment ◽  
Rocky Substratum ◽  
Long Term Effect ◽  
Short And Long Term ◽  
Macroalgal Assemblage

In this paper the results of a manipulative experiment aimed to evaluate the interactive short- and long-term effect of three different stressors, herbivory, nutrient and mucilage, on a macroalgal assemblage are presented. The experiment was conducted in Tavolara Punta Coda Cavallo Marine Protected Area during a bloom of the benthic mucilage-producing microalga Chrysophaeum taylorii Lewis and Bryan (Pelagophyceae), recently spreading in the Mediterranean Sea. On a rocky substratum, 18 plots 20x20 cm in size were prepared and, according to different treatments, nutrients were added in some of them to simulate eutrophication, macroalgae were removed to simulate clearings produced by grazers and mucilage was manually removed to simulate mucilage-free conditions. Differences in the composition of macroalgal assemblages were found when considering the short term effect of the considered stressors, and also the response of the most abundant taxa (DFA, ECA, Dictyotales, Laurencia spp. and Padina pavonica) varied among treatments, proving that a combined effect of such stressors on the recovery of macroalgae was present. On the contrary, the effect of treatments was neither highlighted on the most abundant algae nor on the whole structure of the macroalgal assemblage.

scholarly journals The interactive effect of herbivory, nutrient enrichment and mucilage on shallow rocky macroalgal communities

2018 ◽  
Author(s):  
Sarah Caronni ◽  
Chiara Calabretti ◽  
Giulia Ceccherelli ◽  
Sandra Citterio ◽  
Maria Anna Delaria ◽  
...  
Keyword(s):  
Marine Protected Area ◽  
Interactive Effect ◽  
Term Effect ◽  
Short Term ◽  
Manipulative Experiment ◽  
Rocky Substratum ◽  
Long Term Effect ◽  
Short And Long Term ◽  
Macroalgal Assemblage

In this paper the results of a manipulative experiment aimed to evaluate the interactive short- and long-term effect of three different stressors, herbivory, nutrient and mucilage, on a macroalgal assemblage are presented. The experiment was conducted in Tavolara Punta Coda Cavallo Marine Protected Area during a bloom of the benthic mucilage-producing microalga Chrysophaeum taylorii Lewis and Bryan (Pelagophyceae), recently spreading in the Mediterranean Sea. On a rocky substratum, 18 plots 20x20 cm in size were prepared and, according to different treatments, nutrients were added in some of them to simulate eutrophication, macroalgae were removed to simulate clearings produced by grazers and mucilage was manually removed to simulate mucilage-free conditions. Differences in the composition of macroalgal assemblages were found when considering the short term effect of the considered stressors, and also the response of the most abundant taxa (DFA, ECA, Dictyotales, Laurencia spp. and Padina pavonica) varied among treatments, proving that a combined effect of such stressors on the recovery of macroalgae was present. On the contrary, the effect of treatments was neither highlighted on the most abundant algae nor on the whole structure of the macroalgal assemblage.

scholarly journals Broadening the ecology of fear: non-lethal effects arise from diverse responses to predation and parasitism

2019 ◽  
Author(s):  
D.R. Daversa ◽  
R.F. Hechinger ◽  
E. Madin ◽  
A. Fenton ◽  
A.I. Dell ◽  
...  
Keyword(s):  
Parasite Species ◽  
Short Term ◽  
Lethal Effects ◽  
Response Data ◽  
Defensive Responses ◽  
Ecological Scales ◽  
Data Gaps ◽  
Long Term Consequences ◽  
Ecology Of Fear

AbstractThe ecology of fear demonstrates how prey responses to avoid predation cause non-lethal effects at all ecological scales. Parasites also elicit defensive responses in hosts with associated non-lethal effects, which raises the longstanding, yet unresolved question of how non-lethal effects of parasites compare with those of predators. We developed a framework for systematically answering this question for all types of predator and parasite systems. Our framework predicts that trait responses and their non-lethal effects should be strongest from predators and parasites that do not kill individuals to feed on them, but which nevertheless damage fitness. Analysing trait response data on amphibians, which have been well-studied for this area of research, showed that individuals generally responded more directly to short-term predation risks than to parasitism. Apart from studies using amphibians, there have been few direct comparisons of responses to predation and parasitism, and none have incorporated responses to micropredators, parasitoids, or parasitic castrators, or examined their long-term consequences. Addressing these and other data gaps highlighted by our general framework can advance the field toward understanding how non-lethal effects shape real food webs, which contain multiple predator and parasite species.

Exudation from 14C-labeled fungal propagules in the presence of specific microorganisms

1983 ◽  
Vol 29 (11) ◽  
pp. 1487-1492 ◽  
Author(s):  
D. K. Arora ◽  
A. B. Filonow ◽  
J. L. Lockwood
Keyword(s):  
Phosphate Buffer ◽  
Bacterial Species ◽  
Macrophomina Phaseolina ◽  
Fungal Species ◽  
Bacterial Cells ◽  
Labeled Compounds ◽  
Population Densities ◽  
Cochliobolus Victoriae ◽  
Fungal Propagules

Exudation from 14C-labeled conidia of Cochliobolus victoriae and sclerotia of Macrophomina phaseolina was greater in the presence of cells of five bacterial species or propagules of four fungal species in phosphate buffer or in sterilized soil than in buffer without other microorganisms. In most instances, the increased exudation was statistically significant at P = 0.05. High population densities of bacterial cells or fungal propagules induced greater exudation than lower densities. 14C exudation from C. victoriae conidia in the presence of specific microorganisms was 1.5–9.9% of total label in buffer and 1.0–3.8% on soil; exudation from M. phaseolina sclerotia was 1.4–3.2% of total label in buffer and 1.3–3.2% on soil. All microorganisms tested, except Actinoplanes utahensis and M. phaseolina, suppressed germination of conidia of C. victoriae and sclerotia of M. phaseolina in vitro. Exudation of 14C-labeled compounds was inversely correlated with germination of C. victoriae conidia (r = −0.72) and M. phaseolina sclerotia (r = −0.74). The results indicate that specific microorganisms can enhance exudation from fungal propagules and that the enhanced exudation may be related to the imposition of mycostasis.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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