scholarly journals Activity of Acid Phosphatases in Ectomycorrhizal Fungi

2016 ◽  
Vol 8 (3) ◽  
pp. 78
Author(s):  
Francilina Araujo Costa ◽  
Joselita Cardoso de Souza ◽  
Josimara Nolasco Rondon ◽  
Maria Catarina Megumi Kasuya
Keyword(s):  
Incubation Time ◽  
Mycorrhizal Fungi ◽  
Acid Phosphatases ◽  
Low Concentrations ◽  
P Content ◽  
Mycorrhizal Association ◽  
Incubation Periods ◽  
Low Levels ◽  
Different Sources ◽  
Isoenzyme Patterns

<p>The colonization of plant roots by mycorrhizal fungi, generally increases P content in the host plant when in soils with low levels of P. The objective of this work was to evaluate the activity of acid phosphatases in two isolates of <em>Pisolithus microcarpus</em>, grown in different sources and concentrations of phosphate and to characterize the phosphatase isoenzymes produced by isolates. Both isolates were grown on Melin-Norkrans modified (MNM) medium enriched with organic (Po) or inorganic (Pi) sources of phosphorus, at five different concentrations, in order to study the activity of mycelial surface acid phosphatases during incubation for up to 96 h. Activity of acid phosphatases increased when the fungi were grown without or at low concentrations of Pi. Intraspecific differences were observed between the isolates with regard to acid phosphatase production. A greater decrease in phosphatase activity was observed when incubation time was increased than when Pi concentration was increased. At an incubation time of 96 h, activity of acid phosphatases in isolate 90A increased with increasing Po concentration, while for isolate RV82 remained constant over the different incubation periods and Po concentrations tested. When grown in media without Pi, an additional band appeared in the isoenzyme pattern of RV82, while isoenzyme production was not altered in isolate 90A when grown in media without Pi or with 2 mM Pi, showing differences in their isoenzyme patterns. Isolate 90A possesses a potential competitive advantage when utilized in mycorrhizal association with <em>Eucalyptus </em>because of its ability to utilize Po.</p>

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

scholarly journals Co-Occurrence of Regulated and Emerging Mycotoxins in Corn Silage: Relationships with Fermentation Quality and Bacterial Communities

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 232
Author(s):  
Antonio Gallo ◽  
Francesca Ghilardelli ◽  
Alberto Stanislao Atzori ◽  
Severino Zara ◽  
Barbara Novak ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Dry Matter ◽  
Kojic Acid ◽  
Corn Silage ◽  
Fungal Metabolites ◽  
Fusarium Mycotoxins ◽  
Low Concentrations ◽  
Fermentation Quality ◽  
Low Levels

Sixty-four corn silages were characterized for chemicals, bacterial community, and concentrations of several fungal metabolites. Silages were grouped in five clusters, based on detected mycotoxins, and they were characterized for being contaminated by (1) low levels of Aspergillus- and Penicillium-mycotoxins; (2) low levels of fumonisins and other Fusarium-mycotoxins; (3) high levels of Aspergillus-mycotoxins; (4) high levels of non-regulated Fusarium-mycotoxins; (5) high levels of fumonisins and their metabolites. Altersetin was detected in clusters 1, 3, and 5. Rugulusovin or brevianamide F were detected in several samples, with the highest concentration in cluster 3. Emodin was detected in more than 50.0% of samples of clusters 1, 3 and 5, respectively. Kojic acid occurred mainly in clusters 1 and 2 at very low concentrations. Regarding Fusarium mycotoxins, high occurrences were observed for FB3, FB4, FA1, whereas the average concentrations of FB6 and FA2 were lower than 12.4 µg/kg dry matter. Emerging Fusarium-produced mycotoxins, such as siccanol, moniliformin, equisetin, epiequisetin and bikaverin were detected in the majority of analyzed corn silages. Pestalotin, oxaline, phenopirrozin and questiomycin A were detected at high incidences. Concluding, this work highlighted that corn silages could be contaminated by a high number of regulated and emerging mycotoxins.

Tree species rather than type of mycorrhizal association drives inorganic and organic nitrogen acquisition in tree-tree interactions

2021 ◽  
Author(s):  
Robert Reuter ◽  
Olga Ferlian ◽  
Mika Tarkka ◽  
Nico Eisenhauer ◽  
Karin Pritsch ◽  
...  
Keyword(s):  
Tree Species ◽  
Mycorrhizal Fungi ◽  
Prunus Avium ◽  
N Uptake ◽  
Organic N ◽  
Acer Pseudoplatanus ◽  
N Sources ◽  
Mycorrhizal Association ◽  
N Acquisition ◽  
Inorganic And Organic

Abstract Mycorrhizal fungi play an important role for the nitrogen (N) supply of trees. The influence of different mycorrhizal types on N acquisition in tree-tree interactions is, however, not well understood, particularly with regard to the competition for growth-limiting N. We studied the effect of competition between temperate forest tree species on their inorganic and organic N acquisition in relation to their mycorrhizal type (i.e., arbuscular mycorrhiza or ectomycorrhiza). In a field experiment, we quantified net N uptake capacity from inorganic and organic N sources using 15N/13C stable isotopes for arbuscular mycorrhizal tree species (i.e., Acer pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as ectomycorrhizal tree species (i.e., Carpinus betulus L., Fagus sylvatica L., and Tilia platyphyllos Scop.). All species were grown in intra- and interspecific competition (i.e., monoculture or mixture). Our results showed that N sources were not used complementarily depending on a species´ mycorrhizal association, but their uptake rather depended on the competitor indicating species-specific effects. Generally, ammonium was preferred over glutamine and glutamine over nitrate. In conclusion, our findings suggest that inorganic and organic N acquisition of the studied temperate tree species is less regulated by mycorrhizal association, but rather by the availability of specific N sources in the soil as well as the competitive environment of different tree species.

Warming effects on biomass allocation are jointly regulated by precipitation and mycorrhizal association in terrestrial plants

2021 ◽  
Author(s):  
Xuhui Zhou ◽  
Lingyan Zhou ◽  
Yanghui He ◽  
Yuling Fu ◽  
Zhenggang Du ◽  
...  
Keyword(s):  
Biomass Allocation ◽  
Mycorrhizal Fungi ◽  
Global Scale ◽  
Mean Annual Precipitation ◽  
Shoot Biomass ◽  
Terrestrial Plants ◽  
Terrestrial Carbon ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Mycorrhizal Association

Abstract Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. Recent studies suggest that climate warming can differentially affect root and shoot biomass, and subsequently alter root: shoot ratio. However, warming effects on root: shoot ratio and their underlying drivers at a global scale remain unclear. Using a global synthesis of >300 studies, we here show that warming significantly increases biomass allocation to roots (by 13.1%), and two factors drive this response: mean annual precipitation of the site, and the type of mycorrhizal fungi associated with a plant. Warming-induced allocation to roots is greater in relatively drier habitats compared to shoots (by 15.1%), but lower in wetter sites (by 4.9%), especially for plants associated with arbuscular mycorrhizal fungi compared to ectomycorrhizal fungi. Root-biomass responses to warming predominantly determine the biomass allocation in terrestrial plants suggesting that warming can reinforce the importance of belowground resource uptake. Our study highlights that the wetness or dryness of a site and plants’ mycorrhizal associations strongly regulate terrestrial carbon cycle by altering biomass allocation strategies in a warmer world.

scholarly journals Clostridium chromiireducens sp. nov., isolated from Cr(VI)-contaminated soil

2011 ◽  
Vol 61 (11) ◽  
pp. 2626-2631 ◽  
Author(s):  
K. S. Inglett ◽  
H. S. Bae ◽  
H. C. Aldrich ◽  
K. Hatfield ◽  
A. V. Ogram
Keyword(s):  
Contaminated Soil ◽  
Clostridium Beijerinckii ◽  
Rrna Gene ◽  
Acid Fermentation ◽  
Mixed Acid ◽  
Morphological Studies ◽  
Group I ◽  
Low Concentrations ◽  
Low Levels ◽  
Sequence Similarities

A Cr(VI)-resistant, Gram-positive, spore-forming, obligate anaerobe, designated GCAF-1T, was isolated from chromium-contaminated soil by its ability to reduce Cr(VI) in low concentrations. Mixed acid fermentation during growth on glucose resulted in accumulation of acetate, butyrate, formate and lactate. Morphological studies indicated the presence of peritrichous flagella, pili and an S-layer. The major cellular fatty acids (>5 %) were C16 : 0, C14 : 0, summed feature 3 (comprising iso-C15 : 0 2-OH and/or C16 : 1ω7c), C18 : 1ω7c, C16 : 1ω9c, summed feature 4 (comprising iso-C17 : 1 I and/or anteiso-C17 : 1 B) and C18 : 1ω9c. The DNA G+C content of strain GCAF-1T was 30.7 mol%. Phylogenetic interference indicated that strain GCAF-1T clustered with group I of the genus Clostridium. Of strains within this cluster, strain GCAF-1T shared the highest 16S rRNA gene sequence similarities (98.1–98.9 %) with Clostridium beijerinckii DSM 791T, C. saccharobutylicum NCP 262T, C. saccharoperbutylacetonicum N1-4T, C. puniceum DSM 2619T and C. roseum DSM 51T. However, strain GCAF-1T could be clearly distinguished from its closest phylogenetic neighbours by low levels of DNA–DNA relatedness (<50 %) and some phenotypic features. Based on the evidence presented here, strain GCAF-1T ( = DSM 23318T  = KCTC 5935T) represents a novel species of the genus Clostridium, for which the name Clostridium chromiireducens sp. nov. is proposed.

scholarly journals Acanthamoeba-Campylobacter Coculture as a Novel Method for Enrichment of Campylobacter Species

2007 ◽  
Vol 73 (21) ◽  
pp. 6864-6869 ◽  
Author(s):  
Diana Axelsson-Olsson ◽  
Patrik Ellstr�m ◽  
Jonas Waldenstr�m ◽  
Paul D. Haemig ◽  
Lars Brudin ◽  
...  
Keyword(s):  
Culture Medium ◽  
Bacterial Species ◽  
Oxygen Quenching ◽  
Free Living ◽  
Promising Tool ◽  
Low Concentrations ◽  
Novel Method ◽  
Selective Antibiotics ◽  
Different Sources ◽  
Bacterial Concentrations

ABSTRACT In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 104 CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.

The phosphorus requirement of lettuce: II. A dynamic model of phosphorus uptake and growth

1973 ◽  
Vol 80 (3) ◽  
pp. 353-361 ◽  
Author(s):  
M. A. Scaife ◽  
R. Smith
Keyword(s):  
Dynamic Model ◽  
Phosphorus Uptake ◽  
Normal Growth ◽  
Soil Mass ◽  
Relative Growth ◽  
P Content ◽  
Phosphorus Requirement ◽  
Low Levels ◽  
Parameter Values ◽  
P Supply

SummaryA dynamic model is presented in which the problem of predicting P response is broken down into various components, such as:(a) Weight and P content of emerging seedling.(b) Normal growth curve of the fully nourished plant.(c) A ‘deficiency-tolerance’ factor relating depression of relative growth rate to plant P concentration.(d) An ‘affinity’ term relating sink concentration to P status of plant.(e) A perirhizal resistance term for diffusive transport to roots.(f) Capacity and intensity of P supply from the soil. Mass flow supply via the transpiration stream is also included.By changing parameter values one may attempt to simulate the effect of any of these factors on the shape of the P response curve and any other part of the system throughout crop life. At present the model over-estimates growth at low levels of P supply, but predicted plant P concentrations agree reasonably well with observed data.

scholarly journals The role of strigolactones in host specificity ofOrobancheandPhelipancheseed germination

2010 ◽  
Vol 21 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Mónica Fernández-Aparicio ◽  
Koichi Yoneyama ◽  
Diego Rubiales
Keyword(s):  
Seed Germination ◽  
Host Specificity ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Parasitic Plants ◽  
Parasitic Weed ◽  
Low Concentrations ◽  
Weedy Species ◽  
Germination Requirements

AbstractStrigolactones are apocarotenoids regulating shoot branching. They are also known to be exuded by plant roots at very low concentrations, stimulating hyphal branching of arbuscular mycorrhizal fungi and germination of root parasitic weed seeds. We show that strigolactones play a major role in host specificity ofOrobancheandPhelipanche(the broomrapes) seed germination. This observation confirms that host-derived germination stimulants are an important component determining the host specificity of these parasitic plants. Weedy broomrape species were less specialized in germination requirements than the non-weedy species except forO. cumanaandO. foetidavar.broteri. Similar results were obtained with the root exudates. Some species, such asP. aegyptiacaandO. minor, showed a broad spectrum of host specificity in terms of seed germination, which was stimulated by exudates from the majority of species tested, whereas others, such asO. cumana,O. hederaeandO. densiflora, were highly specific. Some species, such asO. minor,P. aegyptiacaandP. nana, were responsive to the three strigolactones studied, whereas others were induced by only one of them, or did not respond to them at all. The synthetic strigolactone analogue GR24, generally used as a standard for germination tests, was not effective on someOrobancheandPhelipanchespecies. Seeds of some species that did not respond to GR24 were induced to germinate in the presence of fabacyl acetate or strigol, confirming the role of strigolactones in host specificity.

Creep of CdZnTe at high homologous temperatures

1999 ◽  
Vol 14 (10) ◽  
pp. 3864-3869 ◽  
Author(s):  
T. E. Stevens ◽  
J. C. Moosbrugger ◽  
F. M. Carlson
Keyword(s):  
Elevated Temperatures ◽  
Small Strain ◽  
Small Sample ◽  
Dislocation Creep ◽  
Etch Pit Density ◽  
Self Diffusion ◽  
Etch Pit ◽  
Before And After ◽  
Low Levels ◽  
Different Sources

The creep behavior of single-crystal Zn-doped CdTe was examined in the small strain regime. Specimens from two different sources, with tensile axes [110] and [112], were deformed at 1073 and 1173 K. Strain rates were of order 10−6 to 10−7 s−1. A laser interferometer was constructed to measure the small sample displacement. Cadmium overpressure was used to inhibit sublimation of test specimens at elevated temperatures. Some tests showed a transition from secondary to tertiary creep at low levels of strain. An activation energy for steady-state creep was calculated as QC = 1.46 eV, and the creep exponent was found to be approximately n = 4.2. These results, coupled with reported activation energies for self-diffusion of Cd in Cd(Zn)Te, indicate a dislocation creep mechanism. Etch pit density was measured before and after deformation and approached a common level regardless of initial etch pit density.

scholarly journals Tumor necrosis factor-dependent production of human immunodeficiency virus 1 in chronically infected HL-60 cells

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2742-2748 ◽  
Author(s):  
K Kitano ◽  
CI Rivas ◽  
GC Baldwin ◽  
JC Vera ◽  
DW Golde
Keyword(s):  
Human Immunodeficiency Virus ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Virus Production ◽  
Viral Production ◽  
Low Concentrations ◽  
Immunodeficiency Virus ◽  
Lag Period ◽  
Low Levels ◽  
Necrosis Factor

Abstract Tumor necrosis factor (TNF) may play a central role in proviral activation and release from latency in cells infected with the human immunodeficiency virus (HIV). We studied viral production and its relation to TNF in a HL-60 cell line (J22-HL-60) infected with a monocytotropic strain of HIV-1JR-FL. Viral production was stimulated to similar levels by TNF, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), and 1,25-dihydroxyvitamin D3 (1,25[OH]2D3). Production of the virus was not suppressed by 3′-azido-3′-deoxythymidine (AZT), indicating that viral production was not caused by superinfection. Low concentrations of TNF (0.1 ng/mL) induced viral production with a short lag period of 8 hours, and this proviral activation was specifically suppressed by anti- TNF antibodies. However, induction of virus production by 1,25(OH)2D3 showed an extended lag period of 2 to 3 days. The effect of 1,25(OH)2D3 on virus production was also blocked by anti-TNF antibodies, which suggests the direct participation of TNF in this process. TNF accumulated in the culture supernatant of cells stimulated with 1,25(OH)2D3 with a kinetics consistent with its involvement in the action of 1,25(OH)2D3 on viral production. The J22-HL-60 cell line produced low levels of virus when cultured in the absence of an external stimulus; however, this basal viral production was suppressed greater than 80% in the presence of anti-TNF antibodies. Corresponding low levels of TNF were detected in the culture supernatants. Viral production decreased slowly with increasing passage of the cells, and no virus was detected in the supernatants of cells maintained in culture for several months. Concomitantly, TNF was no longer detected in the supernatant of these cells, which suggests that endogenous autocrine production of TNF drives viral production in the unstimulated cells. However, viral production was stimulated in these cells by low concentrations (0.1 ng/mL) of added TNF. These results argue for a central role for TNF in HIV proviral activation in chronically infected myeloid cells.

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