20 research outputs found
Pseudomonas sivasensis 2RO45 inoculation alters the taxonomic structure and functioning of the canola rhizosphere microbial community
Inoculation with plant growth-promoting rhizobacteria (PGPR) is an eco-friendly sustainable strategy for improving crop productivity in diverse environments under different conditions. Our earlier study demonstrated that Pseudomonas sivasensis 2RO45 significantly stimulated canola (Brassica napus L. var. napus) growth. The aim of the present study was to investigate the structural and functional dynamics in the canola rhizosphere microbiome after inoculation with PGPR P. sivasensis 2RO45. The results based on alpha diversity metrics showed that P. sivasensis 2RO45 did not significantly alter the diversity of the native soil microbiota. However, the introduced strain modified the taxonomic structure of microbial communities, increasing the abundance of plant beneficial microorganisms, e.g., bacteria affiliated with families Comamonadaceae, Vicinamibacteraceae, genus Streptomyces, and fungi assigned to Nectriaceae, Didymellaceae, Exophiala, Cyphellophora vermispora, and Mortierella minutissima. The analysis of community level physiological profiling (CLPP) revealed that microbial communities in the P. sivasensis 2RO45 treated canola rhizospheres were more metabolically active than those in the non-treated canola rhizosphere. Four carbon sources (phenols, polymers, carboxylic acids, and amino acids) were better metabolized by the microbial communities from the rhizosphere of plants inoculated with the P. sivasensis 2RO45 than non-inoculated canola rhizospheres. Based on the community-level physiological profiles, the functional diversity of the rhizosphere microbiome was altered by the P. sivasensis 2RO45 inoculation. Substrate utilization Shannon diversity (H) index and evenness (E) index were significantly increased in the treated canola plants. The study provides new insight into PGPR-canola interactions for sustainable agriculture development
The bacterial community composition of the surface microlayer in a high mountain lake
The existence of bacterioneuston in aquatic ecosystems is well established, but little is known about its composition and dynamics, particularly in lakes. The bacterioneuston underlies extreme conditions at the airâwater boundary, which may influence its dynamics in a different way compared with the bacterioplankton. In this study, we assessed quantitative changes in major bacterial groups of the surface microlayer (SML) (upper 900 ÎŒm) and the underlying water (ULW) (0.2â0.5 m depth) of an alpine lake during two consecutive ice-free seasons. Analysis of the bacterial community composition was done using catalyzed reporter deposition FISH with oligonucleotide probes. In addition, several physicochemical parameters were measured to characterize these two water layers. Dissolved organic carbon was consistently enriched in the SML and the dissolved organic matter pool presented clear signals of photodegradation and photobleaching. The water temperature was generally colder in the SML than in the subsurface. The bacterial community of the SML and the ULW was dominated by Betaproteobacteria and Actinobacteria. The bacterial community composition was associated with different combinations of physicochemical factors in these two layers, but temporal changes showed similar trends in both layers over the two seasons. Our results identify the SML of alpine lakes as a microhabitat where specific bacterial members such as of Betaproteobacteria seem to be efficient colonizers
The effect of seed bacterization with Bacillus paralicheniformis 2R5 on bacterial and fungal communities in the canola rhizosphere
Bacillus sp. is one of the best-studied plant growth-promoting rhizobacteria (PGPR). However, more detailed studies targeting its effect on the rhizosphere microbial community are required for improving management practices regarding its commercial application in the field. Our earlier study showed that PGPR Bacillus paralicheniformis 2R5 stimulated canola growth. Hence, this study aimed to assess the time-course impact of B. paralicheniformis 2R5 on bacterial and fungal community structure and diversity. The results showed that inoculation with B. paralicheniformis 2R5 initially significantly decreased the observed bacterial richness compared to the control, while after 44 days of treatment this alpha diversity metrics increased. A linear discriminant analysis effect size showed that B. paralicheniformis 2R5 altered the soil bacterial and fungal community structure by increasing the abundance of plants' beneficial microorganisms such as Nitrospira, Ramlibacter, Sphingomonas, Massilia, Terrimonas as well as Solicoccozyma, Schizothecium, Cyphellophora, Fusicolla, Humicola. B. paralicheniformis 2R5 seems to be a promising alternative to chemical pesticides and can be considered for practical application in the field. Its ability to alter the rhizosphere microbiome by increasing the diversity and composition of bacterial communities and increasing plants' beneficial groups of fungi, appears to be important in terms of improving canola development. However, further studies on these increased microbial taxa are necessary to confirm their function in promoting canola growth
Ocena zanieczyszczenia osadĂłw dennych Dolnej WisĆy na odcinku WyszogrĂłd-ToruĆ na podstawie wskaĆșnikĂłw bakteriologicznych stanu sanitarnego
This paper deals with the evaluation of the sanitary state of bottom sediments of the Lower Vistula
along the section from WyszogrĂłd to ToruĆ. The contamination extent of bottom sediments by
easily decomposable organic matter and substances of faecal origin was defined based, respectively,
on the number of heterotrophic bacteria capable of growth at 22°C and the occurrence of
faecal coli (FC) bacteria. Examination results enabled to classify the bottom sediments of the
Lower Vistula in the studied section as little and moderately loaded with easily decomposable organic
matter, as well as very little, little and moderately polluted with faeces. The highest contamination
with faecal and easily decomposable organic matter was recorded in bottom sediments
of the sites located in WyszogrĂłd and PĆock. Research point situated within the limnic part of the
reservoir in the vicinity of WĆocĆawek was the least contaminated site.Praca ta dotyczy oceny stanu sanitarnego osadĂłw dennych Dolnej WisĆy na odcinku od
Wyszogrodu do Torunia. StopieĆ skaĆŒenia osadĂłw dennych substancjÄ
organicznÄ
Ćatwo rozkĆadalnÄ
oraz substancjÄ
pochodzenia kaĆowego okreĆlono odpowiednio na podstawie liczebnoĆci
bakterii heterotroficznych zdolnych do wzrostu w 22oC oraz wystÄpowania bakterii
z grupy coli typu kaĆowego (FC). Wyniki badaĆ pozwoliĆy zaklasyfikowaÄ osady denne Dolnej
WisĆy na badanym odcinku jako nisko i umiarkowanie obciÄ
ĆŒone substancjÄ
organicznÄ
Ćatwo rozkĆadalnÄ
oraz bardzo nisko, nisko i umiarkowanie zanieczyszczone fekaliami. NajwiÄkszym
zanieczyszczeniem substancjÄ
organicznÄ
Ćatwo rozkĆadalnÄ
i fekalnÄ
odznaczaĆy
siÄ osady denne stanowisk usytuowanych w Wyszogrodzie oraz PĆocku. Stanowiskiem najmniej
obciÄ
ĆŒonymi zanieczyszczeniami byĆ punkt badawczy znajdujÄ
cy siÄ w czÄĆci limnicznej
zbiornika w okolicy WĆocĆawka
Microbial air contamination in indoor environment of a university library
The present study was aimed at evaluating the number of bacteria and mould fungi in the indoor and outdoor environment
of ToruĆ University Library. The sampling sites were located in the rooms serving the functions typical of libraries (i.e. in
the Main Reading Room, Current Periodicals Reading Room, Collections Conservation Laboratory, Old Prints Storeroom,
in rooms serving other (non-library) functions (i.e. main hall, cafeteria, and toilet) as well as outside the library building.
The analyses reveal that the concentrations of bacterial as well as fungal aerosols estimated with the use of the impaction
method ranged between 101-103 CFU·m-3, which corresponds to the concentrations normally observed in areas of this kind.
Evaluation of the hygienic condition of the studied areas was based on the criteria for microbiological cleanliness in interiors
submitted by the European Commission in 1993. According to this classification, the air was considered to be heavily or
moderately contaminated with bacteria, while the air contamination with mould fungi was described as low or moderate.
The air in the Old Prints Storeroom was considered the least contaminated with microbial aerosol
Vliv derivĂĄtĆŻ polyhexamethylen guanidinu zakomponovanĂœch do PolyhydroxybutyrĂĄtu na tvorbu biofilmu a aktivitu bakteriĂĄlnĂch enzymĆŻ
Escherichia coli and Staphylococcus aureus were able to produce biofilm on the surface of polyhydroxybutyrate (PHB), but their abundance depended on type and the concentrations of the polyhexamethylene guanidine (PHMG) derivatives introduced in PHB. Different types of PHMG derivatives inhibited S. aureus ATCC 6538P biofilm formation, but PHB with PHMG salt of sulfanilic acid stimulated E. coli ATCC 8739 biofilm formation. The presence of all PHMG derivatives decreased significantly the number of viable cells of the test bacteria directly proportional to the concentration of the biocidal agent. PHMG derivatives affected the activity of microbiological hydrolases with different degrees. Some of them (PHB with PHMG stearate) stimulated activity of E. coli ATCC 8739 hydrolases, other (PHB with the PHMG salt of sulfanilic acid) inhibited activity of the S. aureus ATCC 6538P hydrolases. The PHMG derivatives introduced in PHB also inhibited the activity of bacterial dehydrogenasespublikace studuje vliv derivĂĄtĆŻ polyhexamethylen guanidinu zakomponovanĂœch do polyhydroxybutyrĂĄtu na tvorbu biofilmu a aktivitu bakteriĂĄlnĂch enzymĆŻ u bakteriĂ E. coli a S. aureus
Microbial communities associated with the anthropogenic, highly alkaline environment of a saline soda lime, Poland
Soda lime is a by-product of the Solvay soda process for the production of sodium carbonate from limestone and sodium chloride. Due to a high salt concentration and alkaline pH, the lime is considered as a potential habitat of haloalkaliphilic and haloalkalitolerant microbial communities. This artificial and unique environment is nutrient-poor and devoid of vegetation, due in part to semi-arid, saline and alkaline conditions. Samples taken from the surface layer of the lime and from the depth of 2 m (both having pH similar to 11 and ECe up to 423 dS m(-1)) were investigated using culture-based (culturing on alkaline medium) and culture-independent microbiological approaches (microscopic analyses and pyrosequencing). A surprisingly diverse bacterial community was discovered in this highly saline, alkaline and nutrient-poor environment, with the bacterial phyla Proteobacteria (representing 52.8% of the total bacterial community) and Firmicutes (16.6%) showing dominance. Compared to the surface layer, higher bacterial abundance and diversity values were detected in the deep zone, where more stable environmental conditions may occur. The surface layer was dominated by members of the genera Phenylobacterium, Chelativorans and Skermanella, while in the interior layer the genus Fictibacillus was dominant. The culturable aerobic, haloalkaliphilic bacteria strains isolated in this study belonged mostly to the genus Bacillus and were closely related to the species Bacillus pseudofirmus, B. cereus, B. plakortidis, B. thuringensis and B. pumilus
Changes in bacterial and archaeal communities during the concentration of brine at the graduation towers in Ciechocinek spa (Poland)
This study evaluates the changes in bacterial and archaeal community structure during the gradual evaporation of water from the brine (extracted from subsurface Jurassic deposits) in the system of graduation towers located in Ciechocinek spa, Poland. The communities were assessed with 16S rRNA gene sequencing (MiSeq, Illumina) and microscopic methods. The microbial cell density determined by direct cell count was at the order of magnitude of 10(7) cells/mL. It was found that increasing salt concentration was positively correlated with both the cell counts, and species-level diversity of bacterial and archaeal communities. The archaeal community was mostly constituted by members of the phylum Euryarchaeota, class Halobacteria and was dominated by Halorubrum-related sequences. The bacterial community was more diverse, with representatives of the phyla Proteobacteria and Bacteroidetes as the most abundant. The proportion of Proteobacteria decreased with increasing salt concentration, while the proportion of Bacteroidetes increased significantly in the more concentrated samples. Representatives of the genera Idiomarina, Psychroflexus, Roseovarius, and Marinobacter appeared to be tolerant to changes of salinity. During the brine concentration, the relative abundances of Sphingobium and Sphingomonas were significantly decreased and the raised contributions of genera Fabibacter and Fodinibius were observed. The high proportion of novel (not identified at 97% similarity level) bacterial reads (up to 42%) in the 16S rRNA gene sequences indicated that potentially new bacterial taxa inhabit this unique environment