scholarly journals Screening of Bacteria for Biosurfactants, Exopolysaccharides and Biofilms and their Impact on Growth Stimulation of Zea mays Grown under Petrol Stress

2021 ◽  
Vol 26 (02) ◽  
pp. 309-316
Author(s):  
Sabiha Habib

Environmental stress imposed by petroleum hydrocarbons can compensate by use of auxin-producing bacteria having potential for biosurfactants production, to assist improved plants’ growth in petrol contaminated areas. In the present work, four auxin-producing bacteria were screened for biosurfactants, exopolysaccharides (EPS) and biofilms production capability. We hypothesized that Enterobacter sp. (A5C) was the most efficient strain with respect to biosurfactant production and can accumulate EPS as well as biofilms. This strain was attributed to exhibit emulsification index, percentage of hydrophobicity and percentage of hydrocarbon degradation more than 50%. Also, it produced 9.27 mg of EPS per 100 mL of culture while Fourier transform infrared spectroscopy (FTIR) confirmed the presence of alcoholic and carboxylic groups, ketone and sugars in it. Results of in vitro plant microbe interaction assay revealed its potential to stimulate the growth of Zea mays L. plants under 1 and 2% of petrol stress by improving physio-chemical attributes of treated plants, over control. Thus, it is concluded that the test organism i.e., Enterobacter sp. (A5C) might be involved in developing bacterial community (EPS and biofilms) that helped to colonize the bacteria to the plant roots and soil particles that ultimately encouraged the more access to nutrients and protection of plant roots from toxins in soil ecosystem. © 2021 Friends Science Publishers

Biologia ◽  
2021 ◽  
Author(s):  
Zuzana Lukacova ◽  
Denis Liska ◽  
Boris Bokor ◽  
Renata Svubova ◽  
Alexander Lux
Keyword(s):  
Zea Mays ◽  

1970 ◽  
Vol 131 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Arthur I. Grayzel ◽  
Carolyn Beck

The mechanism of growth stimulation in allogeneic lymphocytes mixed in vitro was studied at the cell level by means of cytophotometric techniques. A pronounced increase in fluorescence intensity of fixed and acridine orange (AO) stained lymphocytes was observed as soon as after 1–3 hr in mixed culture. No increase in the amount of DNA took place during this time. The higher fluorescence intensity was due to an increased accessibility of AO binding sites in the deoxyribonucleoprotein (DNP) complex, most probably as a result of weakened bonds between the DNA and the protein moiety in the DNP complex. Similar DNP changes have been found in other systems of growth stimulation and may be one prerequisite for later induction of cellular synthetic processes. Increased AO binding only occurred when the lymphocyte donors were incompatible at the major histocompatibility locus (HL-A); there was no change in AO binding in cases of HL-A identity. The AO binding reaction probably reflects a specific recognition of HL-A antigens, whereas other antigenic discrepancies between the individuals do not seem to cause an analogous response.


2011 ◽  
Vol 68 (2) ◽  
pp. 175-181 ◽  
Author(s):  
Deborah Pinheiro Dick ◽  
Simone Benvenuti Leite ◽  
Ricardo Simão Diniz Dalmolin ◽  
Henrique Cesar Almeida ◽  
Heike Knicker

In the last three decades, exotic tree species are being introduced in the natural pastures of the highlands located at the northeastern part of Rio Grande do Sul State (RS), Brazil. This alteration of land use may impart drastic changes in the soil attributes. In this context, this work aimed to evaluate the impact of Pinus taeda afforestation on soil chemical attributes and organic matter (SOM) composition in Leptosols from Campos de Cima da Serra, RS. Soil samples under eight year old (Pi8) and 30 year old (Pi30) Pinus plantations and under native pasture (NP) were studied. Contents of exchangeable cations and of micronutrients and soil pH were determined. The SOM composition was investigated by means of elemental analyses and FTIR spectroscopy. The soil under pasture had a higher content of nutrients and of SOM in comparison to Pinus soils, reflecting the higher input and decomposition rate of the below ground added residue in the grassland environment. The SOM in pasture soils showed a higher content of carbohydrate and of structures derived from microbial metabolism. Besides the depletion of nutrients and of SOM, Pinus afforestation affected the SOM quality: following afforestation, the proportion of chemically recalcitrant structures and of carboxylic groups increased, whereas N-containing groups decreased.


Microbiology ◽  
2011 ◽  
Vol 157 (10) ◽  
pp. 2904-2911 ◽  
Author(s):  
Michael Wyrebek ◽  
Cristina Huber ◽  
Ramanpreet Kaur Sasan ◽  
Michael J. Bidochka

Here we tested the hypothesis that species of the soil-inhabiting insect-pathogenic fungus Metarhizium are not randomly distributed in soils but show plant-rhizosphere-specific associations. We isolated Metarhizium from plant roots at two sites in Ontario, Canada, sequenced the 5′ EF-1α gene to discern Metarhizium species, and developed an RFLP test for rapid species identification. Results indicated a non-random association of three Metarhizium species (Metarhizium robertsii, Metarhizium brunneum and Metarhizium guizhouense) with the rhizosphere of certain types of plant species (identified to species and categorized as grasses, wildflowers, shrubs and trees). M. robertsii was the only species that was found associated with grass roots, suggesting a possible exclusion of M. brunneum and M. guizhouense. Supporting this, in vitro experiments showed that M. robertsii conidia germinated significantly better in Panicum virgatum (switchgrass) root exudate than did M. brunneum or M. guizhouense. M. guizhouense and M. brunneum only associated with wildflower rhizosphere when co-occurring with M. robertsii. With the exception of these co-occurrences, M. guizhouense was found to associate exclusively with the rhizosphere of tree species, predominantly Acer saccharum (sugar maple), while M. brunneum was found to associate exclusively with the rhizosphere of shrubs and trees. These associations demonstrate that different species of Metarhizium associate with specific plant types.


1971 ◽  
Vol 21 (5) ◽  
pp. 247-250 ◽  
Author(s):  
Hirofumi Uchiyama ◽  
Toshiaki Kameya ◽  
Norindo Takahashi

2011 ◽  
Vol 4 (1) ◽  
pp. 22-25 ◽  
Author(s):  
M Bashir ◽  
I Yusuf ◽  
AS Kutama

Five traditional herbal preparations were sampled between May-June, 2009 in Kano. The samples were investigated for invitro antibacterial activities against clinical isolates of Staphylococcus aureus. Likewise, phytochemical screening tests were conducted to determine some of the phytochemicals present in the ethanolic and water extracts of the samples. Various concentrations of the extracts were prepared using serial doubling dilutions (5000=l/ml, 2500=g/ml, 1250=g/ml, 625=g/ml and 312.5=g/ml). All the test extracts showed slight antibacterial activity against the test organism, with ethanolic extract of sample E having the highest zone diameter of inhibition, while sample H had the lowest diameter of inhibition. The standard antibiotic disc (Gentamicin) had demonstrated the highest activity on the test organisms. The results of the Phytochemical screening revealed the presence of steroid in all the samples, tannin in samples A, C, D and E, reducing sugars in sample A, D and E respectively. The result of the minimum inhibitory concentration (MIC) was found to be above 312.5=g/ml for samples C, D and E. Keywords: Staphylococcus aureus, Herbal preparations, antibacterial activity, Phytochemical screening and minimum inhibitory concentration.


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