scholarly journals Identification and use of actinomycetes for enhanced nodulation of soybean co-inoculated with Bradyrhizobium japonicum

2003 ◽  
Vol 49 (8) ◽  
pp. 483-491 ◽  
Author(s):  
A K Gregor ◽  
B Klubek ◽  
E C Varsa

The utilization of actinomycetes as potential soybean (Glycine max (L.)) co-inoculants was evaluated. Soil samples from Carbondale and Belleville, Ill., were used to inoculate pre-germinated soybean plants to determine antibiotic sensitivity in the native Bradyrhizobium japonicum population. Sensitivity was in the order kanamycin > tetracycline > oxytetracycline > rifampicin > neomycin. Antagonism by five actinomycete cultures toward seven test strains of B. japonicum was also assessed. The ranking average inhibition (across all seven B. japonicum strains) by these actino mycetes was Streptomyces kanamyceticus = Streptomyces coeruleoprunus > Streptomyces rimosus > Streptomyces sp. > Amy colatopsis mediterranei. Ten antibiotic combinations were used to isolate antibiotic-resistant mutants of B. japonicum I-110 and 3I1B-110 via successive cycles of mutation. Eighty-one antibiotic-resistant strains were isolated and tested for symbiotic competency; nine of which were selected for further characterization in a greenhouse pot study. Few differences in nodule number were caused by these treatments. Nodule occupancy varied from 0% to 18.3% when antibiotic-resistant strains of B. japonicum were used as the sole inoculants. However, when three mutant strains of B. japonicum were co-inoculated with S. kanamyceticus, significant increases in nodule occupancy (up to 55%) occurred. Increases in shoot nitrogen composition (27.1%–40.9%) were also caused by co-inoculation with S. kanamyceticus. Key words: Bradyrhizobium japonicum, Streptomyces kanamyceticus, indigenous bradyrhizobia, co-inoculation, nodule occupancy.

1990 ◽  
Vol 36 (12) ◽  
pp. 839-845 ◽  
Author(s):  
T. J. McLoughlin ◽  
S. Hearn ◽  
S. G. Alt

The population dynamics of six introduced Bradyrhizobium japonicum strains were measured over three growing seasons in a Wisconsin soil with a low incidence of indigenous B. japonicum (10 cells/gm). Four antibiotic-resistant members of the 123 serocluster (which were either spectinomycin resistant or streptomycin resistant), USDA 110, and USDA 138 were inoculated using liquid inoculum, at a rate of 1 × 108 cells per 2.5-cm row, on two soybean cultivars in 1985. Nodule occupants were identified using an enzyme-linked immunosorbent assay (ELISA), fluorescent antibodies, and antibiotic-resistant mutants. In the first growing season, 100% of the nodules were formed by the introduced strains. The nodules from the uninoculated plots were occupied by an indigenous 110 serogroup. In the second and the third season at the same site (without further inoculation), a high percentage (> 60%) of the nodules from all the plots were nodulated by the 123 serocluster (either alone or as mixed infections). However, < 25% of the nodules in the 123-inoculated plots and < 9% in the other plots were formed by any of the antibiotic-marked 123 inoculum strains introduced in 1985. The main conclusions are (i) that it is possible to successfully introduce inoculum strains in soils where the indigenous Bradyrhizobium population is low and to obtain 100% nodule occupancy in the first growing season, and (ii) that successful inoculation in one year in soils with a low incidence of Bradyrhizobium does not ensure that the introduced inoculum strains will form nodules in subsequent years. Key words: Bradyrhizobium japonicum, indigenous bradyrhizobia, interstrain competition, field trials.


1986 ◽  
Vol 32 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Thomas J. McLoughlin ◽  
Scott G. Alt ◽  
P. Ann Owens ◽  
Corrine Fetherston

Nodulation of Glycine max (L) Merr. by six Rhizobium fredii strains was measured in two Midwestern fields containing high indigenous populations of Bradyrhizobium japonicum (3 × 105/gm soil). The soils were inoculated with antibiotic-resistant mutants using liquid inoculum at two levels on soybean cv. Peking and cv. Jacques 130. Strain establishment was measured 40 days after planting. In the first year, USDA206, USDA217, and USDA257 were the most competitive strains, occupying greater than 50% of the nodules on cv. Peking in both soils. None of the strains were competitive on Jacques 130. In the second growing season, all nodules were formed by the indigenous population on both cultivars, suggesting that these fast-growing strains do not persist in Midwestern soils.


1987 ◽  
Vol 33 (11) ◽  
pp. 990-995 ◽  
Author(s):  
Stephen F. Dowdle ◽  
B. Ben Bohlool

We studied the competition between Bradyrhizobium japonicum and Rhizobium fredii isolates for nodulation of soybean (Glycine max L. Merrill) cultivars Williams and Ai Jiao Zao grown in three different soils in pots. Two of the soils were from People's Republic of China, one from a soybean field in Honghu with no history of Rhizobium inoculation, and one from a rice field in Wuhan with no history of soybean cultivation. The Honghu soil contained B. japonicum and R. fredii (log total number g−1 = 5.82 ± 0.58); whereas the Wuhan soil only contained B. japonicum (log total number g−1 = 2.80 ± 0.52). Inoculation did not result in a significant increase in nodule number on plants in either soil. Uninoculated plants of both cultivars harbored only R. fredii in the Honghu soil and only B. japonicum in the Wuhan soil. Even when B. japonicum were inoculated into the Honghu soil, R. fredii occupied the majority of the nodules on both cultivars. In the Wuhan soil, B. japonicum serogroups USDA110 and USDA136b (= CB1809) occupied the majority of the nodules except when an isolate of R. fredii from the soybean soil was added in high numbers. In a Hawaiian soil devoid of B. japanicum or R. fredii, when soybeans were inoculated with isolates of both species, most of the nodules were formed by B. japonicum. The R. fredii isolate could form up to 20% of nodules in this soil, but only on the Ai Jia Zao cultivar. In the Wuhan but not the Hawaiian soil, peat pelleting of seeds with equal numbers of two B. japonicum and one R. fredii isolates increased nodule occupancy by B. japonicum USDA136b serogroup significantly as compared with when the same isolates were inoculated into the soil. The results reported here highlight the critical importance of being indigenous to the competitive success of B. japonicum and R. fredii in nodulation of their soybean host.


1988 ◽  
Vol 66 (4) ◽  
pp. 683-686 ◽  
Author(s):  
Jeanne M. L. Selker ◽  
John Imsande ◽  
Eldon H. Newcomb

Early emergent nodules on roots of hydroponically grown soybean plants (Glycine max (L.) Merr.) were sectioned serially to locate the site of infection by Bradyrhizobium japonicum. The plants had been inoculated only after their root systems had produced numerous higher order branches. The hydroponic solutions contained all required nutrients, including either a suboptimal concentration of nitrate (0.5 mM) or an excess of nitrate (4.0 mM). In all six nodules examined, three with suboptimal nitrate and three with excess nitrate, we found a centrally located root hair containing an infection thread. We conclude that mature root systems of soybean grown in aqueous culture can undergo infection through root hairs in the way that is typical of young seedlings grown either in pots of vermiculite or pouches.


2021 ◽  
Vol 12 (4) ◽  
pp. 15-25
Author(s):  
D. P. Gladin ◽  
A. R. Khairullina ◽  
A. M. Korolyuk ◽  
N. S. Kozlova ◽  
O. V. Ananyeva ◽  
...  

Background. Staphylocci are the leading pus-forming Gram-positive bacteria in the childrens hospitals. The prevalence of the antibiotic resistant strains among them limits therapeutic effects of infections in children. Aim. The research is aimed at characterizing the species of staphylococcus, which are isolated from the different clinical specimens of the patients at the clinics of Saint Petersburg State Pediatric Medical University in 2019, and analysis of their susceptibility to antimicrobial agents. Materials and metods. According to the clinical recommendations of 2018, susceptibility to antimicrobial drugs (AMD) was revealed in 860 strains of staphylococci determined by the disc diffusion method, which were identified by the automated analyser Vitek-2 compact. Results. Six species of staphylococci were represented at the hospital departments, among which Staphylococcus epidermidis prevailed in the departments of the neonate pathology department and intensive care units (63.0% and 46.2% respectively), Staphylococcus aureus is commonly found at the departments of surgery and the departments of the therapeutic profiles (61.7% and 46.2% respectively). More than a half of the staphylococci strains (63.0%) were resistant to at least one of the antimicrobial drugs. Vancomycin and line solid showed the highest activity to these staphylococci. High specific weight of multidrug resistant (MDR) bacteria (37.8%) and extensively drug resistant (XDR) strains of the phenotype (33.0%) was revealed. The level of antibiotic resistant strains was the highest in Staphylococcus haemolyticus (98.1%) and S. epidermidis (82.0%), while the specific weight of the resistant ones, MDR and XDR strains was extremely low among S. aureus (16.2%, 1.5% and 0.4 respectively), as well as in methicillin-resistant isolates (0.8%). Conclusions. A great variety of antibiotic resistance was revealed among the staphylococci. The prevalence of these strains in the pediatric hospitals requires constant local monitoring of the antibiotic resistant staphylococci.


2019 ◽  
Vol 1 (2) ◽  
pp. 18-22
Author(s):  
O A Nazarchuk ◽  
V I Nahaichuk

Introduction. Non-fermenting Gram-negative bacilli are known as one of the most frequent causative agents of hospital-acquired infections. Acinetobacter baumannii, as causative agent of infection complications of different localization, has obtained recently high resistance to anti-biotics and has belonged to ESKAPE group of pathogens. Antimicrobials, recommended for the prophylaxis and therapy of hospital-acquired infections, have been failing in their effectiveness and lead to selection of antibiotic resistant strains of A. baumannii. The aim of this research was to substantiate the way of overcoming of resistance in clinical strains of A. baumannii, by means of synergic antimicrobial activity of antibiotics and antiseptic decamethoxinum®. Material and methods. The research was carried out on 190 clinical strains of A. baumannii, isolated from patients with burn disease during the period 2011–2015. The sensitivity of clinical strains of A. baumannii was determined to such antibiotics as ampicillin/sulbactam, cefoperazone, cefoperazone/sulbactam, meropenem, imipenem, amikacin, ciprofloxacin, gatifloxacin and antiseptic decamethoxinum® (DCM; Registration certificate No UA/14444/01/01 since 24.06.2015. Order of the Ministry of Health of Ukraine No 373). The sensitivity of A. baumannii to antibiotics and DCM was determined by means of disk diffusion test and serial dilution (Order of the Ministry of Health of Ukraine No167 since 05.04.2007; EUCAST expert rules).The study of the influence of antiseptic DCM on the sensitivity of acinetobacteria to antibiotics was studied on 35 clinical strains of A. baumannii, drafted from the general number of isolates enrolled in the research. For this, the sensitivity of A. baumannii to antibiotics in the presence of sub-minimal inhibitory concentrations (subMIC) of DCM was identified. The received experimental data were analyzed by “Statistica 6.0”. Results and discussion. The changes of antibiotic sensitivity profile of A. baumannii for five years were shown. It was found that the sensitivity of A. baumannii to majority of antibiotics, selected for study, decreased significantly. But the only ampicillin/sulbactam was found to have vice versa tendency. We found the rising quantity of antibiotic resistant strains of A. baumannii. At the same time, high resistance of acinetobacteria to fluoroquinolones (ciprofloxacin– 96,1%; gatifloxacin– 95,8%) was found in 2015. The in vitro research of combined activity of DCM antiseptic remedy and early mentioned antibiotics against clinical strains of A. baumannii demonstrated the reveal antibiotic effectiveness. As follows, minimal inhibitory concentrations of antibiotics decreased in 1.5–4 times in the mediums which contained subMIC of DCM. Especially this tendency was found in resistant clinical strains. Conclusion. Under selective influence of antibiotics protected by β-lactamase inhibitors, carbapenems, fluoroquinolones aminoglycosides increase the antibiotic resistance in A. baumannii, causative agents of infectious complications in patients with burn disease. The antiseptic remedy decamethoxinum® helps to improve antibiotic sensitivity in resistant A. baumannii.


AGRICA ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 138-150
Author(s):  
Kristina Erniyani

Bacteria Bradyrhizobium spp. From nodules on soybean plants, bind nitrogen from the air and make it freely available to plants. Amount of nitrogen fixed depends on the ability of a strain to form nodules, nodule effectiveness and environmental conditions. On land – land that had been planted with soybeans, inoculation with Bradyrizhobium bacteria are often not required. To test these lands in the district of Ende, NTT has conducted an experiment with a factor in the design of Randomized Complete with nine treatment groups. The treatment consists of (i) inoculation with the soybean crop in the ground former Ekoae (R1), (ii) inokulasi with soil former soybean plants in Ndona (R2), (iii) inoculation of soybean plants with the soil used in Flores (R3), (iv) Brady rhizobium isolates from soybean nodules in Ekoae (R4), (v) Bradyrhizobium isolates from nodules of soybean plants is in Ndona (R5), (v) Bradyrhozobium isolates from nodules of soybean plants at Flores (R6) (vii) a commercial inoculant legin (L), (viii) fertilizer nitrogen (N), and (ix) Control (K). all treatments were repeated 4 times. Land used in these experiments is the land of Ndona. The experiment was carried out since faculty, Udayana University. The highest percentage of effective nodules on the treatment Bradyrhizobium isolates from sybean nodules in Ndona (R5). Total nitrogen levels at the age of 45 HST in the highest in soybean plants that received 100 kg ha-1 urea and soybeans that have a desolate Bradyrhizobium inoculation of soybean nodules in Ndona (R). Efficiency and levels of symbiotic nitrogen fixation result obtained highest in soybean plants that received an inoculation Bradyrhizobium diisolat soybean nodules in Ndona (R5). Oven dry weight of plants that from the age of 45 HST on all isolates are equivalent to the oven-dry weight of plants at the fertilization of 100 kg ha- 1 urea. The result shoed that the land – the land of Ekoae, Ndona and Fkres have high Bradirhizobium contain bacteria. Bacteria Bradyrhizobium cp. Most numerous in the isolates from soybean nodules in Ndona (R5) the most efficient from effective nodules is 82.26% and as high as the 0.52% N fixate. These results indicate that isolates from Ndona Bradyrhizobiun veeb able to form effective nonudel on yoy beans grown in soil from Ndona. The result also indicates inoculation with a commercial inoculant was obtained not on land – land planted with soybeans used


2012 ◽  
Vol 25 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Peter van Berkum ◽  
Patrick Elia ◽  
Qijian Song ◽  
Bertrand D. Eardly

A multilocus sequence typing (MLST) method based on allelic variation of seven chromosomal loci was developed for characterizing genotypes (GT) within the genus Bradyrhizobium. With the method, 29 distinct multilocus GT were identified among 190 culture collection soybean strains. The occupancy of 347 nodules taken from uninoculated field-grown soybean plants also was determined. The bacteroid GT were either the same as or were closely related to GT identified among strains in the culture collection. Double-nodule occupancy estimates of 2.9% were much lower than values published based on serology. Of the 347 nodules examined, 337 and 10 were occupied by Bradyrhizobium japonicum and B. elkanii, respectively. The collection strains within the species B. japonicum and B. elkaniialso were compared with Bradyrhizobium cultures from other legumes. In many cases, the observed GT varied more according to their geographic origin than by their trap hosts of isolation. In other cases, there were no apparent relationships with either the legume or geographic source. The MLST method that was developed should be a useful tool in determining the influence of geographic location, temperature, season, soil type, and host plant cultivar on the distribution of GT of Bradyrhizobium spp.


2020 ◽  
Vol 65 (1) ◽  
pp. 37-41
Author(s):  
I. V. Shipitsyna ◽  
E. V. Osipova ◽  
E. N. Ovchinnikov ◽  
D. S. Leonchuk

Due to the spreading highly resistant strains among clinically significant P. aeruginosa clones, it becomes necessary to prescribe antibiotics not only taking into account the knowledge of sensitivity spectrum of a particular isolate but the data of microorganism biofilm activity as well. To study the dependence of biofilm-forming ability on the sensitivity to antibacterial preparations of P. aeruginosa clinical strains, isolated from patients with chronic osteomyelitis. 36 patients above 18 with chronic osteomyelitis of long tubular bones who were treated in the center of purulent osteology took part in the experiment. Object of the study - material isolated from wounds, fistulas, as well as from inflammatory foci. The sensitivity of isolated microorganisms to 10 antibiotics was analyzed: Piperacillin/Tazobactam, Imipenem, Meropenem, Aztreonam, Amikacin, Ciprofloxacin, Ceftriaxone, Ceftazidime, Cefotaxime, Cefepime. High- and medium-adhesive strains accounted for 86,1 % among P. aeruginosa clinical isolates, obtained from the wounds of patients with chronic osteomyelitis of long tubular bones. Highly adhesive strains are resistant to a wide range of antibacterial preparations used clinically. Penicillins were the most effective preparations when analyzing antibioticograms obtained for highly adhesive strains, for medium adhesive strains - penicillins, aminoglycosides and carbapenems, for low adhesive ones - aminoglycosides, penicillins, carbapenems, monobactams, quinolones. P. aeruginosa multi-resistance is a serious problem in the treatment of patients with chronic osteomyelitis. Spreading antibiotic-resistant strains of P. aeruginosa is associated with the presence of bacteria in the biofilm. Since adhesion is the first step in the biofilm formation, it is important to identify strains having high adhesive ability timely.


Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3152 ◽  
Author(s):  
Yana Ilizirov ◽  
Andrei Formanovsky ◽  
Irina Mikhura ◽  
Yossi Paitan ◽  
Faina Nakonechny ◽  
...  

The well-known and rapidly growing phenomenon of bacterial resistance to antibiotics is caused by uncontrolled, excessive and inappropriate use of antibiotics. One of alternatives to antibiotics is Photodynamic Antibacterial Chemotherapy (PACT). In the present study, the effect of PACT using a photosensitizer Rose Bengal alone and in combination with antibiotics including methicillin and derivatives of sulfanilamide synthesized by us was tested against antibiotic-sensitive and antibiotic-resistant clinical isolates of Gram-positive S. aureus and Gram-negative P. aeruginosa. Antibiotic-sensitive and resistant strains of P. aeruginosa were eradicated by Rose Bengal under illumination and by sulfanilamide but were not inhibited by new sulfanilamide derivatives. No increase in sensitivity of P. aeruginosa cells to sulfanilamide was observed upon a combination of Rose Bengal and sulfanilamide under illumination. All tested S. aureus strains (MSSA and MRSA) were effectively inhibited by PACT. When treated with sub-MIC concentrations of Rose Bengal under illumination, the minimum inhibitory concentrations (MIC) of methicillin decreased significantly for MSSA and MRSA strains. In some cases, antibiotic sensitivity of resistant strains can be restored by combining antibiotics with PACT.


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