Colony initiation in flax rust in axenic culture: involvement of a volatile factor

1979 ◽  
Vol 57 (23) ◽  
pp. 2657-2662 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Carbon Dioxide ◽  
Axenic Culture ◽  
Conclusive Evidence ◽  
Culture Flask ◽  
Melampsora Lini ◽  
Air Space ◽  
Lag Period ◽  
Axenic Cultures ◽  
Incubation Temperatures

In axenic cultures of flax rust (Melampsora lini) colonies are initiated after a lag period of 12–20 days, depending partly on incubation temperatures. Colony initiation is completely inhibited by removal of a volatile factor which is absorbed by KOH in the air space of the culture flask. The fungus remains sensitive to this inhibition for 8–10 days, i.e., until shortly before visible colonies would normally have developed. While in the presence of KOH, the fungus is not killed; cultures grow normally after removal of the KOH.Although conclusive evidence must await further work, the available data strongly suggest that carbon dioxide is responsible for this effect.

The effects of CO2 and membranes on sporulation in axenic cultures of flax rust

1985 ◽  
Vol 63 (8) ◽  
pp. 1418-1422 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Membrane Surface ◽  
Volatile Substances ◽  
Melampsora Lini ◽  
Paraffin Oil ◽  
Air Space ◽  
Saran Wrap ◽  
Axenic Cultures ◽  
Diffusion Of Gases

Uredospore production by axenically grown flax rust (Melampsora lini (Ehrenb.) Lev.) was measured as carotenoids (extinction units at 458 nm) per milligram protein. Sporulation was not affected by raising (flushing with 1–5% (v/v) CO2 in air) or lowering (KOH well in culture flasks) the level of CO2 in the air space above the cultures. Significant (two- to four-fold) increases in sporulation occurred beneath impermeable membranes of Parafilm or Saran wrap placed on the surface of young (3 weeks from seeding) mycelial mats for 2 weeks. The stimulatory effect was confined strictly to those areas of the mycelial mats in contact with the membranes. Both Parafilm and Saran wrap were easily and cleanly peeled away from the mycelial mats. Permeable Unipore and HVHP membranes, to which the fungus adhered strongly, did not stimulate sporulation. The fungus did not adhere to Unipore or HVHP membranes treated with silicone or paraffin oil; membranes thus treated stimulated sporulation. The stimulatory effect of membranes on sporulation appears to depend on the nature of the contact between the membrane surface and the mycelium and to be unrelated to the effect of the membranes on the diffusion of gases or other volatile substances.

Axenic culture of flax rust isolated from cotyledons by cell-wall digestion

1972 ◽  
Vol 50 (12) ◽  
pp. 2601-2603 ◽  
Author(s):  
W. David Lane ◽  
Michael Shaw
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Cell Walls ◽  
Hydrolytic Enzymes ◽  
Axenic Culture ◽  
Rust Fungi ◽  
Host Cells ◽  
Melampsora Lini ◽  
Large Numbers ◽  
Axenic Cultures

A technique is described for the isolation of colonies of flax rust (Melampsora lini (Ehrenb.) Lév., Race No. 3) from infected cotyledons. The technique depends on the digestion of the host cell walls with hydrolytic enzymes and washing of the liberated colonies. It is thus possible to collect large numbers of flax-rust colonies with only a few host cells adhering to them. Axenic cultures were established from colonies isolated in this way. This technique may be useful in establishing axenic cultures of other rust fungi.

A simple rapid procedure for obtaining axenic cultures from monoxenic cultures of myxomycete plasmodia

1999 ◽  
Vol 45 (10) ◽  
pp. 865-870 ◽  
Author(s):  
S Balaji ◽  
A Sujatha ◽  
I Kalyanasundaram
Keyword(s):  
Axenic Culture ◽  
Differential Staining ◽  
Complex Media ◽  
Associated Bacteria ◽  
Rapid Procedure ◽  
Substrate Preferences ◽  
Axenic Cultures ◽  
Time Required

Axenic culture of myxomycete plasmodia has been attempted from time to time by various authors, but with very little success. From over 500 known species of myxomycetes, fewer than 20 species have been reported in axenic culture to date, including axenic myxamoebal cultures. In these cultures, the plasmodia required either complex media, or a killed bacterial supplement for growth. Furthermore, the time required for attaining the axenic state varied from several months to years. In the present study, a simple, rapid procedure has been developed to render monoxenic plasmodial cultures axenic. This procedure is based on our discovery that plasmodia have certain unusual substrate preferences that are inhibitory to the associated bacteria using Physarella oblonga as a model. The presence or absence of the bacteria could be ascertained through incubation in four different bacteriological media and by the use of a differential staining technique.Key words: myxomycetes, axenic culture, hydrocarbon utilization, bacterial associates.

scholarly journals Using New Gas Exchange Methods to Estimate Mesophyll Conductance and Non-stomatal Inhibition of Photosynthesis Caused by Water Deficits

HortScience ◽  
2012 ◽  
Vol 47 (6) ◽  
pp. 687-690 ◽  
Author(s):  
James Bunce
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Soil Water ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Stomatal Closure ◽  
Carbon Dioxide Concentration ◽  
Mesophyll Conductance ◽  
Water Deficits ◽  
Air Space

Soil water deficits remain one of the most important factors reducing the yield of crop plants and may become even more limiting with changes in the global climate and competition for fresh water resources. Soil water deficits reduce plant growth partly by reducing photosynthesis. However, it remains unclear how important non-stomatal factors are in limiting photosynthesis under moderate water stress and whether rising atmospheric carbon dioxide may alter which processes limit photosynthesis under water stress. The conductance to CO2 from the substomatal air space to the site of carboxylation inside chloroplasts in C3 plants is now termed mesophyll conductance. Because of the competition between CO2 and O2 for RuBisco, the carbon dioxide concentration at the chloroplast can be estimated from the O2 sensitivity of photosynthesis, providing a new method of estimating mesophyll conductance. It has also recently been realized that partial stomatal closure resulting from water stress can often be reversed by exposing leaves to low CO2. This provides a new means of assessing the non-stomatal component of the inhibition of photosynthesis by water stress. These methods were applied to four C3 species and revealed that mesophyll conductance decreased substantially with water stress in two of the four species and that reopening of stomata did not eliminate the reduction in photosynthesis caused by moderate water stress at either the current ambient or elevated CO2 concentrations.

scholarly journals Effect of axenic culture and NAA in Vitro on masoyi (Cryptocarya massoy (Oken) Kosterm) seeds regeneration

2021 ◽  
Vol 914 (1) ◽  
pp. 012016
Author(s):  
Y Wibisono ◽  
A I Putri ◽  
Y Hadiyan ◽  
L Haryjanto ◽  
L Hakim ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Germination Rate ◽  
Axenic Culture ◽  
Culture Method ◽  
Ms Medium ◽  
Controlled Conditions ◽  
Axenic Cultures ◽  
One Year ◽  
The Impact

Abstract The high valuable endemic commodities in Papua, Masoyi’s (Cryptocarya massoy) population facing great threat due to unsustainable harvest system. Generative propagation faces significant challenges due to seed characteristics and habitat conditions. Controlled conditions and the role of hormones have an important effect on generative growth. This study aimed to determine the influence of axenic culture with sterilization treatments Isothiazolone Biocide (IB) and 1-Naphtaleaneacetic Acid (NAA) in Murashige and Skoog (MS) medium on seed regeneration and to observe the development of seedlings at the acclimatization stage. The tissue culture method was used. The highest percentage of axenic cultures (57%) was obtained with 5% of BI. The germination rate of masoyi seeds was achieved by 100%. Furthermore, it showed varied responses depending upon concentrations of NAA, the addition of 1 ml l−1 NAA in MS medium is recommended. Acclimatization has been successfully carried out in the greenhouse (67% survival rate) and excellent seedlings growth at nursery (52.35 + 0.6 cm in height after one year transferred). The impact of the controlled conditions and the addition of NAA to axenic cultures in vitro increased the germination of masoyi seeds. Axenic culture and hormones were also important requirements for mass propagation of masoyi by tissue culture.

Metabolism and disposition of difluoromethane (HFC32) in the mouse

1996 ◽  
Vol 15 (7) ◽  
pp. 592-596 ◽  
Author(s):  
Martin K Ellis ◽  
Jacky L Naylor ◽  
Michael A Collins ◽  
Trevor Green
Keyword(s):  
Carbon Dioxide ◽  
Inhalation Exposure ◽  
Total Radioactivity ◽  
Systemic Absorption ◽  
Dose Equivalent ◽  
Faecal Excretion ◽  
Post Exposure ◽  
Air Space ◽  
Liver And Kidney ◽  
Specific Retention

1 Difluoromethane (HFC32) is under development as a replacement for chlorofluorocarbons (CFCs) in some refrigeration applications. 2 The metabolism and disposition of [14C]-difluoro methane ([14C]-HFC32) was determined in male Swiss mice as a consequence of a single 6 h inhalation exposure to atmospheres of 10 000 p.p.m. 3 Of the inhaled dose, about 1-2% was recovered in expired air, urine, faeces and carcass suggesting that systemic absorption of this hydrofluorocarbon from the alveolar air space of the lung into blood is poor. Upon cessation of exposure the majority of the systemically absorbed HFC32 was exhaled within 1 h. 4 Carbon dioxide was a major metabolite of HFC32. Carbon dioxide measured post-exposure accounted for about 0.3% of the inhaled dose. Urinary and faecal excretion of non-volatile metabolites accounted for about 0.34% and 0.07% of the inhaled dose, respec tively. 5 Carbon monoxide could not be detected. 6 Total metabolism, measured as the sum of the radio activity recovered in urine, faeces, as carbon dioxide and that retained in the carcass, amounted to about 0.8% of the inhaled dose, equivalent to 64% of the total radioactivity recovered. 7 Analysis of a range of tissues at 4 days post-exposure showed a relatively uniform distribution of radio activity with the highest concentration in the lung, liver and kidney. There was no evidence of a specific retention in any organ or tissue.

692. The influence of carbon dioxide on the growth of lactic streptococci

1958 ◽  
Vol 25 (1) ◽  
pp. 24-31 ◽  
Author(s):  
H. R. Whitehead ◽  
P. A. Jones ◽  
P. S. Robertson
Keyword(s):  
Carbon Dioxide ◽  
Yeast Extract ◽  
Initial Rate ◽  
Skim Milk ◽  
Initial Growth ◽  
Free Gas ◽  
Rate Of Growth ◽  
Optimum Proportion ◽  
Lag Period ◽  
Long Chains

The initial rate of growth ofStr. lactisandStr. cremorisin skim-milk depends upon the proportion of CO2present in solution. When CO2is constantly swept from the milk medium by a stream of CO2-free gas all strains show a very prolonged lag period. They eventually emerge from this lag period after more than 8 hr. and grow well enough to coagulate the milk within 24 hr. For optimal initial growth the lactic streptococci require the presence in solution in the milk of proportions of CO2within the range 0·2 and 2·3% by volume. Some strains have a higher CO2requirement within this range than others. Skim-milk after sterilization contains less than the optimum proportion of CO2for many strains of lactic streptococci.Yeast extract in a proportion of about 0·5% can substitute for CO2in skim-milk.The periodic inversion of cultures in plain skim-milk reduces the initial rate of growth of some of the streptococci, particularly those which form long chains. The reason for this is unknown. It does not occur when yeast extract is present.

Effect of heat shock on protein synthesis in flax rust uredosporelings

1985 ◽  
Vol 63 (11) ◽  
pp. 2069-2076 ◽  
Author(s):  
Maichael Shaw ◽  
Rosalinda Boasson ◽  
Leroy Scrubb
Keyword(s):  
Heat Shock ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Heat Stroke ◽  
Sodium Dodecyl ◽  
Axenic Culture ◽  
One Dimensional ◽  
Melampsora Lini ◽  
Molecular Masses ◽  
Shock Proteins

In uredosporelings of Melampsora lini (Ehrenb.) Lév. germinated for 3 h, uptake of [35S]methionine and its incorporation into protein were depressed during a 2-h heat shock induced by transfer from 17 ± 0.5 to 31 °C. Spectrophotometric scans of fluorograms, prepared after one-dimensional sodium dodecyl sulphate – polyacrylamide gel electrophoresis of aliquots of protein extracts containing equal numbers of disintegrations per minute (1 dps = 1 Bq) in protein, showed that heat shock induced statistically significant changes in the relative degrees of incorporation of [35S]methionine into 15 polypeptide bands. Increased labelling occurred in seven bands, which appear to be heat shock proteins with apparent molecular masses of 84, 71, 43.5, 30.5, 19.5, 18, and 17 kD. Decreased labelling occurred in eight bands, which appear to be heat stroke proteins with apparent molecular masses of 56, 54, 48, 46, 34, 32, 31.5, and 14 kD. When [35S]methionine was administered during heat shock at 31 °C the same pattern of polypeptide labelling was observed in extracts made immediately without return to 17 °C and in extracts made after uredosporelings were returned to 17 °C for 24 h. Thus label incorporated into each polypeptide during heat shock was retained for at least 24 h after the return to 17 °C. Administration of [35S]methionine at 17 °C after completion of the heat shock showed that the "normal" or "nonshock" pattern of labelling began to be resumed within 2 h after transfer from 31 to 17 °C. The results are discussed in relation to the effect of heat shock in promoting the initiation and growth of mycelial colonies from uredosporelings in axenic culture.

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