A Comparison of the effects of several concentrations of oxgall in platings of soil fungi

1951 ◽  
Vol 29 (1) ◽  
pp. 26-31 ◽  
Author(s):  
J.J. Miller ◽  
D.J Peers ◽  
R.W. Neal

A study was made of the effect of adding varying concentrations of dehydrated bile to soil extract agar and potato dextrose agar in platings from two Ontario soils. The development of colonies of bacteria and actinomycetes was retarded, but no decrease was noted in the number of fungus colonies that appeared in the plates. The crowding effect of certain bacteria and fungi was lessened, facilitating the counting and isolation of individual fungus cultures.


1959 ◽  
Vol 5 (5) ◽  
pp. 431-439 ◽  
Author(s):  
Norman James

Numbers of bacteria and of fungi in a saline soil were about one-fifth of numbers in a Red River clay soil. Bacterial counts on two soil-extract agar media, one prepared from the saline soil and the other from Red River soil, were the same, and the populations on the two were the same as shown by the replica plating technique. They were larger than counts on sodium albuminate agar or on asparagin–mannitol agar. Likewise, fungal counts on either soil-extract agar, with 0.02% dipotassmm phosphate, 0.1% glucose, and 0.1% peptone, were higher than counts on Waksman's acidified medium, or on Martin's medium, or on Smith and Dawson's medium. Interestingly, fungal counts on a medium with the same three chemicals as the soil-extract media but with the soil extract replaced by water were as high as those on the soil-extract media. Different levels of potassium phosphate were tested in each of the above media. In each medium for bacteria, and in each for fungi, counts varied inversely as the amount of potassium phosphate. The same held true when sodium phosphate was used instead of potassium phosphate in each medium.



1963 ◽  
Vol 9 (6) ◽  
pp. 741-751 ◽  
Author(s):  
Donald D. Kaufman ◽  
Lansing E. Williams ◽  
Charles B. Sumner

The effects of 20, 25, or 30 °C incubation temperatures for dilution-plates and of five plating media (Ohio Agricultural Experiment Station Medium (OAES), Liftman"s crystal-violet agar, dextrose-peptone agar, soil-extract agar, and glucose-nitrate soil-extract agar) on total numbers and types of fungi isolated from two soils (sugar beet or corn cropped) by a soil-dilution plate method were determined. The data revealed that significant differences existed among the three variables as well as their interactions. Although numbers of colonies of fungi isolated were not affected significantly, the types of fungi (number of individual genera) isolated were significantly greater in sugar beet than in corn cropped soils. In nearly all instances, the greatest total number and types of fungi were isolated at temperatures of 20 or 25 °C. Although each medium appeared to favor one or more groups of fungi, the overall frequency and distribution of fungi was essentially the same on all media. On the basis of its transparency, total number and types of fungi isolated, the elimination of bacteria and actinomycetes, and its restriction of rapidly growing fungi, the OAES medium was deemed the most suitable for use in the soil-dilution plate method.



2003 ◽  
Vol 81 (4) ◽  
pp. 294-306 ◽  
Author(s):  
S I Mpofu ◽  
R Hall

Verticillium dahliae Kleb. is a serious pathogen of many plant species. Growth media used to measure population density of V. dahliae in soil were evaluated for high recovery of the pathogen, as well as accuracy and precision of population estimates from naturally and artificially infested sandy loam soil using the soil dilution method. Recovery of V. dahliae from naturally infested field soil was highest on soil pectate Tergitol agar (SPT), soil extract agar + sodium polypectate (SEAP), modified pectate agar (MPA), potato dextrose agar + streptomycin sulphate (PDAS), and Talboys' prune lactose agar (TPA); however, PDAS and TPA were overgrown with contaminating fungi, making enumeration difficult. Use of SPT medium resulted in the most precise population estimate with a standard error (SE) of 12.6% of the mean followed by use of pectate agar (PA) (SE = 14.8%) and SEAP (SE = 19.1%). Ethanol, biotin, and Dox salts enhanced recovery of V. dahliae from naturally infested soil, but combining Dox salts with ethanol and biotin significantly reduced population density. Soil extract had no significant effects on population density. Accuracy of V. dahliae population estimates from sterile artificially inoculated soil was highest on modified soil extract agar (MSEA) (64%) followed by SPT (58%). However, accuracy of V. dahliae population estimates from nonsterile artificially inoculated soil was highest on SPT (36%). Soil extract is not an essential ingredient and biotin may increase recovery of V. dahliae from soil.Key words: Verticillium dahliae, verticillium wilt, population density, recovery, accuracy, precision.



2013 ◽  
Vol 2 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Evan Mitchell Lutton ◽  
Rosa Schellevis ◽  
Anupama Shanmuganathan

Soil bacteria comprise a largely untapped resource with only 1-10% of bacterial species predicted to live in soil being culturable in the laboratory. Establishing culture-dependent protocols that identify unique operational taxonomic units (OTUs) is an important research topic in soil bacterial ecology. The culturability of soil bacteria may be improved by employing different culture media due to inherent preferences of growth substrate utilization. Soil-extract agar, R-2A agar, and 1% nutrient agar were used in this study to isolate bacteria obtained from soil samples collected in winter months to increase the understanding of bacterial diversity in Abernathy Field Station, a Marcellus shale temperate forest in Washington, Pennsylvania. Changes in bacterial diversity can be used to assess the early impact of anthropological factors, such as hydraulic fracturing in the Marcellus shale region, which may lead to severe environmental problems. For the purpose of long term ecological monitoring, data obtained from this year’s sample collection were analyzed in conjunction with previous years’ assessments. Bacterial isolates were analyzed taxonomically and phylogenetically. Unique OTUs were identified through comparative analysis of 16S rDNA. The Shannon-Weaver and Simpson’s diversity indices ranked isolates on soil-extract agar highest for species richness, and rarefaction analysis suggests that sampling saturation of OTUs identified on soil-extract agar has not yet been reached. Each culture medium studied supported isolates of four common phyla: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Soil-extract agar supported the greatest proportion of pigmented colonies including a Cyanobacterium which exhibited intra-16S rDNA polymorphism. Each culture medium supported the growth of unique OTUs and genera with Bacillus, Flavobacterium, Pseudomonas, Rhizobium, and Streptomyces found on each. This study suggests that utilizing different culture media can increase the culturability of soil bacteria.



2012 ◽  
Vol 6 (2) ◽  
pp. 158 ◽  
Author(s):  
Dayane Rodrigues Youssef ◽  
Giovanni Ribeiro de Souza ◽  
Kátia De Lima Nechet ◽  
Bernardo De Almeida Halfeld-Vieira

O objetivo desse trabalho foi caracterizar isolados do fungo Rhizoctonia associados à queima foliar, obtidos de hospedeiros de importância econômica no estado de Roraima. Os isolados foram obtidos de plantas de feijão-caupi (Vigna unguiculata), soja (Glycine max), seringueira (Hevea brasiliensis), melancia (Citrullus lanatus), alface (Lactuca sativa) e feijão-guandu (Cajanus cajan). Os parâmetros utilizados foram números de núcleos, grupo de anastomose e as características culturais da colônia, taxa de crescimento micelial e a formação de escleródios nos meios de cultura: batata dextrose agar (BDA), BDA+asparagina, BDA+extrato de levedura, Czapek Agar, maltose-peptona-agar, soil extract agar, sacarose-yeast-asparagina e V-8. Todos os 10 isolados estudados foram caracterizados como multinucleados e pertencentes à espécie Rhizoctonia solani. Três isolados de feijão-caupi, um de soja e o isolado de melancia foram identificados como AGI-1A e um isolado de feijãocaupi, um de soja e o isolado de feijão-guandu como AGI-1B. O isolado de seringueira não foi identificado como nenhum dos padrões de anastomose utilizado. Para a maioria dos isolados as maiores taxas de crescimento micelial foram obtidas no meio de cultura Soil Extract Agar. Dois tipos de escleródios, característicos do grupo AGI, foram observados: formação de 2-20 tufos.placa-1 coloração variável, 1-2 mm e formação de 38-611 microescleródios placa-1, de coloração marrom, medindo 100 μm. A produção e o tipo de escleródio variaram com o isolado e o meio de cultura utilizado.



1954 ◽  
Vol 69 (6) ◽  
pp. 735 ◽  
Author(s):  
ALEXANDER BAKERSPIGEL




2005 ◽  
Vol 99 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Takefumi Hamaki ◽  
Motomasa Suzuki ◽  
Ryosuke Fudou ◽  
Yasuko Jojima ◽  
Takayuki Kajiura ◽  
...  


1933 ◽  
Vol 8 (6) ◽  
pp. 545-552 ◽  
Author(s):  
W. C. Broadfoot

The antagonistic and compatible growth relationships of 66 cultures of bacteria and fungi, most of which were from the soil, towards O. graminis on potato dextrose agar and Molisch's salt peptone agar, were compared with the effect of each on the virulence of this pathogene on wheat seedlings in open soil culture.Of the 21 cultures which controlled the virulence of O. graminis in the soil, only 15 of these were antagonistic on potato dextrose agar, while of the 45 cultures which gave intermediate or no control, 17 were compatible and 28 were decidedly antagonistic. From data secured indirectly, the antagonism or compatibility of the micro-organisms toward O. graminis, observed on potato dextrose agar, did not seem to depend on active alkali or acid more than on other metabolic products. The study apparently demonstrates that the growth reaction of various micro-organisms and O. graminis, associated on the two solid media used, is not a reliable indication that the same micro-organism will or will not suppress the virulence of this pathogene on wheat in soil in open pot culture.



1955 ◽  
Vol 33 (3) ◽  
pp. 281-288 ◽  
Author(s):  
R. G. Atkinson ◽  
J. B. Robinson

In tests with seven different liquid media in which the common nitrogen source was potassium nitrate and the carbohydrate substrate was glucose, at a concentration of only 0.1%, most of the 1914 soil fungi isolated fell into one of three nutritional groups requiring, respectively, for maximum growth amino acids, amino acids plus growth factors, or yeast extract. Relatively few isolates required growth factors alone or a combination of yeast and soil extracts. Most of the isolates grew poorly in the basal medium containing only mineral salts, and glucose, with or without soil extract. Although fungi requiring yeast extract were much less frequently isolated from soil on, rather than remote from, tubers grown in a soybean green-manured plot, isolates requiring amino acids, or yeast plus soil extracts, were correspondingly increased on immature and mature tubers, respectively. In a second plot, however, not specially treated, no differences were observed in the nutritional spectra of fungi isolated from the two kinds of soil environment.



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