scholarly journals Paper-based inoculum of Bacillus megaterium and its practical application for simple culture preparation

2019 ◽  
Vol 72 ◽  
pp. 195-204
Author(s):  
Mana Kanjanamaneesathian ◽  
Wasunan Nimanong

The bacterium Bacillus megaterium can be used to biologically control sheath blight and grain discoloration in rice. Large-scale inoculations using liquid cultures are cumbersome so the efficacy of an alternative, paper-based system was examined. Bacterial endospores were embedded on filter papers and multiplied using a simple culture technique. The resulting suspension was used to pre-soak yardlong bean and cucumber seeds before sowing to assess its effect on seed germination and weight. The efficacy of the bacterium in protecting cucumber seeds from pre-emergent damping-off was also examined. The population of bacteria embedded in paper declined initially but remained stable for 150 days at room temperature. Bacterial culture reduced seed germination of cucumber and seedling weight of yardlong beans. Dilution with water either increased or reduced germination of cucumber seeds depending on concentration. A 1:10 v/v dilution increased cucumber-seed germination in a pre-emergent damping-off pot test but all seedlings later died, irrespective of treatment. Paper-based inoculum has the potential to replace liquid inoculum but further work is required to optimise the concentrations of the bacterial culture to achieve disease control without adversely affecting the host plant.

Author(s):  
Haque ME ◽  
◽  
Parvin MS ◽  

Rhizoctonia solani causes pre-emergence and post-emergence damping-off, as well as crown and root rot of sugar beet (Beta vulgaris L.), which significantly affects the yield returns in the USA and Europe. The pathogen overwinters as sclerotia or melanized mycelium. Traditionally, the resistance of cultivars to R. solani is evaluated by scoring disease reactions at the crowns and roots of older seedlings, thus resistance is not evaluated during seed germination. Moreover, earlier studies evaluated cultivars resistance to R. solani using colonized whole barley or wheat grains which, unlike sclerotia, are artificial inocula of the pathogen that require time, space and technical know-how to produce. Moreover, colonized grains are prone to contamination with other pathogens, consumed by rodents/birds while applied in the field, and are often uneconomic. Considering those limitations, a study was undertaken (1) to develop in vitro methods to generate large-scale sclerotia, (2) to compare pathogenic potentials of sclerotia, mycelia, and colonized barley grains for optimization of dampingoff assays, and (3) to evaluate Rhizoctonia resistance of selected commercial cultivars during the seed germination phase. Comparing six different culture media, we found that R. solani had the highest radial growth (8.9 ± 0.04, cm³) at 8-days and the maximum number of sclerotia produced (203 ± 4.6) at 28-days in CV8 medium. We demonstrated significant differences in pathogenicity of the three different forms of R. solani inocula and susceptibility of cultivars to preand post-emergence damping-off. The highest pre-emergence damping-off and root rot were observed with sclerotia, and the highest post-emergence dampingoff was recorded with both sclerotial and colonized barley inocula. In addition, varietal differences in susceptibility to pre- and post-emergence damping-off were noted. The highest pre-emergence damping-off was recorded on cv Crystal 101RR and lowest in Maribo MA 504. The highest post-emergence damping-off was recorded on BTS 8500 and the lowest in Crystal 467. The maximum mean root rot was observed in BTS 8500, BTS 8606, and Crystal 101R. Our studies demonstrated that sclerotia serve as efficient natural inocula, reemphasized that host-pathogen interactions differ at the early vs. late stages of sugar beet growth, and highlighted the need to reevaluate commercial sugar beet cultivars for resistance at the seed germination stage.


2016 ◽  
Vol 40 (1) ◽  
pp. 5-8
Author(s):  
Bashar Sadeq Noomy

      The aim of this study is to determine the sensitivity of bacterial culture technique in the detection of Brucella abortus in milk samples of aborted cows. Sixty samples of milk were collected from aborted cows during a period which did not exceed two months after the abortion. All of them were positive for rose bengal test. Results showed that Brucella abortus was isolated from 7 out of 60 (11.6%) from the milk of aborted cows, while PCR test showed that 32 out of 60 (53.3%) milk sample contained Brucella abortus. The specificity of culture techniques was 10%, but its sensitivity was only 21.8%. Beside the cautions in dealing with live Brucella abortus (as culture), it is also less sensitive than PCR, though it is better to use PCR technique in the diagnosis of brucellosis in aborted cows milk.


1993 ◽  
Vol 16 (12) ◽  
pp. 843-846 ◽  
Author(s):  
J.C. Gerlach ◽  
K. Klöppel ◽  
C. MÜller ◽  
N. Schnoy ◽  
M.D. Smith ◽  
...  

Utilizing a modified culture technique for hepatocytes, a high performance suspension culture is possible in which hepatocytes spontaneously form cell aggregates. The aggregates of 20-100 cells have been histologically confirmed to hold a three-dimensional structure, they show a long-term external metabolism and a survival time comparable with standard adhesion cultures. This technique has several advantages in the construction of large scale bioreactors for hybrid liver support systems.


1998 ◽  
Vol 22 ◽  
pp. 323-325
Author(s):  
M. C. Hickey ◽  
A. P. Moloney ◽  
M. O'Connell ◽  
J. Connolly

In vitro techniques have been developed to facilitate the measurement of nutritional variability amongst food. Many kinetic studies have utilized the modified Tilley and Terry technique, with long-term incubations carried out in Erlenmeyer flasks. These are inefficient in utilizing incubator space for large scale studies. However substitution of Erlenmeyer flasks with tubes as fermentation units leaves the system prone to ‘bridging’, the formation of dense mats of forage particles by entrapped gas, above the level of the media in a fermentation unit. The objective of experiment 1 was to establish an effective incubation technique to eliminate the random variation caused by bridging.


2020 ◽  
Vol 13 (1) ◽  
pp. 30-36
Author(s):  
Karen A. Haubensak ◽  
Sara Grove ◽  
Jeffrey Foster ◽  
Ingrid M. Parker

AbstractWe conducted a large-scale, multiple-year study in harvested areas of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) forests in western Washington, examining the effectiveness of control methods on the widespread invasive shrub Scotch broom [Cytisus scoparius (L.) Link]. We tested both chemical and physical control methods, using three different approaches that are management relevant: (1) triclopyr, a POST herbicide, at different times of year and on different-sized plants; (2) cutting (or brushcutting) of mature individuals; and (3) scarification of soil surface to remove seedlings once versus multiple times. We measured initial mortality, seed germination, and percent cover of C. scoparius in plots for 3 yr following treatments. Triclopyr treatment resulted in greater mortality and reduced percent cover compared with all other treatments with the effect persisting for 2 yr after spraying. Further, triclopyr had the same effect on C. scoparius cover and mortality irrespective of time of year applied. Similar to soil scarification, triclopyr treatments resulted in a flush of seedlings, suggesting that removal of conspecific competitors and not soil disturbance per se promotes seed germination. Brushcutting was generally effective in reducing C. scoparius cover in the short term, but effects did not persist as long as triclopyr treatments, in part due to large differences in stump resprouting rates across sites. Soil scarification to remove seedlings, even over multiple years, did not result in reduced C. scoparius cover. Triclopyr is an effective approach for controlling both emerging and established stands of C. scoparius.


2019 ◽  
Vol 17 (1) ◽  
pp. 893-901 ◽  
Author(s):  
Małgorzata Wyciszkiewicz ◽  
Marcin Sojka ◽  
Agnieszka Saeid

AbstractThis paper discusses the effect of the utilization of Bacillus megaterium in the microbial solubilization process where poultry bones or ash were used as a source of renewable phosphorus. The process was performed in a large scale laboratory. The pH of the solution decreased during one-week solubilization, which had a direct influence on the increased concentration of phosphorus determined in the solution. It was proved that the phosphorus concentration in the solution was significantly correlated with the biomass concentration and pH. The trial allowed verification of the suitability of the method to prepare two P fertilizers: one based on poultry bones and one on ashes. The elemental analysis of their composition suggests that the bones are a P-bearing resource with properties better than ash. That enables for more efficient scaling-up the solubilization although the concentration of total phosphorus was comparable in both cases. The total amount (100%) of phosphorus was present in a form available to plants in the formulation based on the poultry bones, while 64% of plant available phosphorus was present in the formulation based on the ash. The concentration of Cd was significantly lower in the case of fertilizer based on bones with respect to ash.


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