Comparative analysis of five methods for recovering rhizobacteria from cotton roots

1991 ◽  
Vol 37 (12) ◽  
pp. 953-957 ◽  
Author(s):  
Joseph W. Kloepper ◽  
Walter F. Mahaffee ◽  
John A. McInroy ◽  
Paul A. Backman

A variety of methods have been used for recovering introduced bacteria from plant roots. The objective of this study was to compare systematically five methods: agitation in buffer, agitation with glass beads in buffer, mixing in a StomacherR lab-blender, sonication, and trituration with mortar and pestle. Cotton seeds were treated with two previously reported rhizobacterial strains, Pseudomonas fluorescens strain Pf-5 and Bacillus subtilis strain GB03. The efficiency of recovery by each method was determined 3 weeks later by comparing average bacterial populations from whole root systems, single 2.0-cm root segments, and two root regions (the uppermost 5 cm of taproot and the lowermost 5 cm). Treatment with the StomacherR blender yielded significantly higher (P = 0.05) mean populations of GB03 compared with all other methods and significantly higher mean populations of Pf-5 compared with agitation with glass beads. From the lowermost 5 cm of taproot, populations of Pf-5 recovered by the StomacherR treatment were significantly higher than all other methods. The inclusion of glass beads for agitation treatments resulted in neither consistently higher absolute numbers of recovered bacteria nor reductions in variability. The mean standard error of each recovery method varied among root sources, and no single method consistently had the highest or lowest mean standard error. Mean standard errors for strain GB03 were generally lower than those for Pf-5 with each root source and each method of recovery. When viewed in composite, the data suggest that the StomacherR treatment was the best for recovering the greatest absolute numbers of rhizobacteria; however, this treatment had high mean standard errors. Investigations of root colonization by introduced rhizobacteria should include several recovery methods to optimize recovered numbers or to decrease variability, depending on the experimental objectives. Key words: root colonization, rhizobacteria, Pseudomonas fluorescens, Bacillus subtilis, cotton.

2016 ◽  
Vol 8 (3) ◽  
pp. 1699-1703
Author(s):  
Anurag Yadav ◽  
Kusum Yadav

A study was undertaken to compare the survival efficacy of two native, previously characterized bacterial biovars viz. Bacillus subtilis BCU5 and Pseudomonas fluorescens PCU17 with Bacillus subtilis strain MTCC1789 and Pseudomonas fluorescens strain MTCC4828, procured from Institute of Microbial Technology, Chandigarh,India in cumin rhizosphere and bulk soil. All the four bacterial types were made rifampicin resistant and the mutants were applied as inoculants at the dosage of 6 log, 7 log and 8 log colony forming units (cfu) g-1 dry soil weight in pots containing cumin seedlings. The cfu of rhizosphere and bulk soil of pots was observed per week for four weeks. The results show that the initial population decline is a common feature of bioinoculants. In rhizosphere and bulk soil, the native bacterial biovars survived better than their procured counterparts. The population of P. fluorescens strain MTCC4828r in rhizosphere soil declined faster and reached below detection limit whereas the P. fluorescens biovar PCUr rhizosphere final population dropped to 3.1 log, 2.9 log and 2.13 log cfu g-1 soil dry weight with 8 log, 7 log and 6 log cfu g-1 soil dry weight inoculum treatment, respectively. In contrast to P. fluorescens strain MTCC4828r, the population of B. subtilis strain MTCC1789r stabilized after some decline and was comparable with B. subtilis biovar BCU5 population. Study concludes that the inoculant population decline in soil was the result of lower microbial load carrying capacity of soil than the provided inoculum densities. Also, the native bacteria survived better than procured ones in rhizosphere soil.


2020 ◽  
Vol 52 (3) ◽  
Author(s):  
Lyudmila P. Ermakova ◽  
Grigory A. Nozdrin ◽  
Sergei N. Tishkov ◽  
Yana V. Novik ◽  
Nikita A. Gotovchikov ◽  
...  

The current literature is not comprehensive concerning the influence of Bacillus subtilis on lipid metabolism, egg chemical characteristics, and intestinal microbiota of Japanese quail. The aim of this study was to evaluate the effects of a Bacillus subtilis strain on yolk quality, gut bacterial populations, and total cholesterol and triglyceride concentrations in the plasma of organically farmed Pharaon quail layers. Forty-five-day-old female quails were randomly distributed into four groups of 10 birds each: a no-treatment control group and three test groups receiving powder of Bacillus subtilis DSM 32424 at a minimum rate of 1 × 106 colony forming units per gram, dissolved in drinking water at doses of 50, 75 and 100 mg per kg body weight, daily during 30 days. The use of the probiotic at doses of 50 and 100 mg resulted in significantly reduced faecal staphylococci count on day 30 (P<0.05), while no significant changes were detected in lactobacilli or coliform bacteria. This study gives the first evidence of the influence of Bacillus subtilis on acid value and carotenoid levels in egg yolks laid by quails. Carotenoids were significantly elevated in the 75 mg group on day 30 (P<0.05), but significantly decreased in the 50 and 100 mg groups (P<0.05). Acidity, triglyceride and total cholesterol concentrations in quail serum were not affected significantly by the treatment throughout the study, though their values were reduced. The inclusion of Bacillus subtilis DSM 32424 in drinking water for laying Pharaon quails inhibited faecal staphylococci proliferation and enhanced yolk carotenoid content. Therefore, it can be proposed that including this probiotic in laying quail diets may have beneficial outcomes for both layers and the second generation.


1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.


2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mathilde Nordgaard ◽  
Rasmus Møller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos‐Monterrosa ◽  
Ákos T. Kovács

2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Daniel R. Reuß ◽  
Andrea Thürmer ◽  
Rolf Daniel ◽  
Wim J. Quax ◽  
Jörg Stülke

Bacillus subtilis ∆6 is a genome-reduced strain that was cured from six prophages and AT-rich islands. This strain is of great interest for biotechnological applications. Here, we announce the full-genome sequence of this strain. Interestingly, the conjugative element ICE Bs 1 has most likely undergone self-excision in B. subtilis ∆6.


1979 ◽  
Vol 179 (2) ◽  
pp. 333-339 ◽  
Author(s):  
A Y Strongin ◽  
D I Gorodetsky ◽  
I A Kuznetsova ◽  
V V Yanonis ◽  
Z T Abramov ◽  
...  

Intracellular serine proteinase was isolated from sporulating cells of Bacillus subtilis Marburg 168 by gramicidin S-Sepharose 4B affinity chromatography. The enzymological characteristics, the amino acid composition and the 19 residues of the N-terminal sequence of the enzyme are reported. The isolated proteinase was closely related to, but not completely identical with, the intracellular serine proteinase of B. subtilis A-50. The divergence between these two intracellular enzymes was less than that between the corresponding extracellular serine proteinases (subtilisins) of types Carlsberg and BPN′!, produced by these bacterial strains. This may be connected with the more strict selection constraints imposed in intracellular enzymes during evolution.


Sign in / Sign up

Export Citation Format

Share Document