scholarly journals Reduction of hexavalent chromium by Bacillus spp. isolated from heavy metals-polluted soil

2019 ◽  
Vol 25 (3) ◽  
pp. 247-258
Author(s):  
Dora Ilic ◽  
Ivica Dimkic ◽  
Hadi Waisi ◽  
Panagiotis Gkorezis ◽  
Saud Hamidovic ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Heavy Metal Concentration ◽  
Bacterial Isolates ◽  
Industrial Facilities ◽  
Bacillus Safensis ◽  
Bacillus Spp ◽  
Polluted Sites ◽  
Chromium Tolerance ◽  
Selection Of

Hexavalent chromium, Cr(VI), one of the major pollutants from industrial facilities, is very toxic and harmful for human health and environmental quality. Due to the lack of conventional methods, bioremediation was recommended as an environmentally friendly and effective technique. The aim of this paper was the isolation, identification and selection of the microorganisms which are capable of Cr(VI) reduction in vitro. Heavy metal concentration, detected in four soil samples, within and around the former bicycle factory ?Rog? (Republic of Slovenia), was measured using the ICP-OES method. Bacteria were isolated and tested for chromium tolerance using LB agar supplemented with various Cr(VI) concentrations, whilst Cr(VI) reduction and bacterial growth was determined using the LB liquid medium. From 53 bacterial isolates, five of them showed a tolerance of 1000 mg/L of Cr(VI). Those five isolates showed the capability of growth under various Cr(VI) concentrations (50-1000 mg/L). Initial Cr(VI) concentrations ranging from 50 to 100 mg/L were completely reduced by four bacterial isolates, whilst 500 to 1000 mg/L by Bacillus safensis 342-9. Using 16S rDNA and tuf gene sequence analyses, isolates 270-9R and 342-9 were identified as Bacillus safensis, isolates 351-9 and 270-9C as Bacillus subtilis subsp. subtilis, and 212-9 as Bacillus thuringiensis. These results indicated that these bacteria may be promising tools for remediation of metal-polluted sites.

The ability of rhizosphere bacteria isolated from nematode host and non-host plants to influence the hatch in vitro of the two potato cyst nematode species, Globodera rostochiensis and G. pallida

Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 375-387 ◽  
Author(s):  
N. Aileen Ryan ◽  
Peter Jones
Keyword(s):  
Sugar Beet ◽  
Host Plant ◽  
Host Plants ◽  
Nematode Species ◽  
Cyst Nematode ◽  
Potato Cyst Nematode ◽  
Globodera Pallida ◽  
Bacterial Isolates ◽  
Bacillus Spp

AbstractSeventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .

Clone selection of in vitro horseradish hairy root cultures

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
R Bertóti ◽  
Á Alberti ◽  
A Böszörményi ◽  
R Könye ◽  
T Horváth ◽  
...  
Keyword(s):  
Hairy Root ◽  
Hairy Root Cultures ◽  
Root Cultures ◽  
Clone Selection ◽  
Selection Of

The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Selection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
High Concentration ◽  
Short Term ◽  
High Concentrations ◽  
Selection Of ◽  
Selection Of Resistance ◽  
Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

Wheat Germ Cell-Free Translation System as a Tool for In vitro Selection of Functional Proteins

2002 ◽  
Vol 5 (6) ◽  
pp. 473-480
Author(s):  
Bentham Science Publisher A.N. Alexandrov ◽  
Bentham Science Publisher V.Yu. Alakhov ◽  
Bentham Science Publisher A.I. Miroshnikov
Keyword(s):  
Germ Cell ◽  
Wheat Germ ◽  
In Vitro Selection ◽  
Translation System ◽  
Free Translation ◽  
Selection Of
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