Bacillus bacteria are advantageous antagonistic organisms that can be used as bio-control agents. This study is aimed at screening the antagonistic activity of different strains of isolated Bacillus bacteria and molecular identification of the superior chitinase producer strain against dermatophytes fungi. Soil samples were collected from different places of Kotoor city, Gharbia Governorate, Egypt and Al Madina Al Munawwarah, Kingdom of Saudi Arabia. A collection of Bacillus isolated from soil was tested in vitro against the dermatophytes: Microsporum sp. and Trichophyton sp. The bacterial strains Kh-B1 and Kh-B2 showed the highest antagonistic activity against dermatophytes pathogenic fungi. The highest amount of chitinase productivity (13.6 units/ml) was obtained from the original Bacillus strain (Kh-B1) at 3 days of incubation. BLAST analysis of the amplified 16S ribosomal RNA gene sequence identified the Bacillus strain (Kh-B1) as Paenibacillus macerans. Upon the mutation induction by UV light, the highest chitinase-producing mutant was Kh-UVB-4 as it showed 305.88 percent production higher than the wild-type strain. While, upon the mutation induction by EMS, the highest amount of chitinase produced was 54.8 units/ml by mutant Kh-ESB-20, and it has produced 402.94% more than the original untreated strain. The application of RAPD-PCR protocol using three 15-mer random primers was used to determine the genetic effects of mutagenic treatments on the wild type strain (Kh-B1) as well as to demonstrate the genetic variability between the five most chitinase producing mutants and the wild type (Paenibacillus macerans).
Heavy metals found in nature and the excessive accumulations of heavy metals have an impact on humans and animals. Different effects resulted from the toxicity of heavy metal, that damage the functioning of different organs: brain, lungs, kidney and other essential organs and lowering the levels of energy. Cadmium and lead considered being toxic to organisms in a particular concentration. Patients with renal failure concerned contaminated drinking water with cadmium and lead. Biofilm produced by microbes and it is important for the remediation of pollutants. This study aimed to isolate and investigate the ability of bacterial isolates to produce a biofilm that can resistance heavy metals (cadmium chloride (CdCl 2) and lead nitrate Pb (No 3) 2). Isolates were isolated from soil sample located at different locations from Saudi Arabia (Makkah, Taif and Jeddah). Fifty isolates have been tested for formation of biofilm by two methods. First method was Congo Red Agar CRA and the second was Tissue Culture Plate TCP. Results revealed that 3 out of 50 isolates showed high biofilm formation. The three (A2, ST and PS) isolates that form strong biofilm were screened primarily on nutrient agar plate contain 7ppm concentration of CdCl 2 and Pb (NO 3) 2. Results indicated that all three isolates were resistance. The maximum tolerance concentration (MTC) of three (A2, ST and PS) isolates studied on nutrient agar plate supplemented with different concentrations from CdCl 2 and Pb (NO 3) 2 respectively. Results indicated that MTC values of Pb (NO 3) 2 were up to (450, 350 and 500 ppm) for ST, A2 and PS isolates respectively. While in CdCl 2 the MTC values were (150, 120 and 250 ppm) for ST, A2 and PS isolates respectively. The effect of CdCl 2 and Pb (NO 3) 2 on bacterial growth using spectrophotometer, and results indicated that all three isolates (A2, ST and PS) growth decreased with the increase in concentration of Pb (NO 3) 2 and CdCl 2. Three isolates were identified by biochemical and 16S rRNA gene. The isolates identified as B. cereus A2, B. cereus st and P.aeruginosa PS and submitted to NCBI under accretion numbers (MK450303 and MK450304 for B. cereus A2, B. cereus ST) respectively. Plasmid curing was studied using the method of elevated temperature, and results showed that all cured B. cereus A2 and P. aeruginosa PS colonies were resistance to 7ppm of CdCl 2 and Pb (NO 3) 2 while B. cereus ST showed different pattern of resistance after curing. B. cereus ST selected for test removal Pb (NO 3) 2 and CdCl 2 using inductively coupled plasma optical emission spectrometry (ICP-OES). Using ICPOES showed removal lead up to 93% while in cadmium to 49 %. Antimicrobial susceptibilities patterns of identified bacteria were determined. All tested isolated strains showed resistance against to 3 or more antibiotics. Three strains B. cereus A2, B. cereus st and P. aeruginosa PS that isolated from soil, showed the highest biofilm formation which considered important factor for heavy metals resistance. The biofilm represents a very renewa...
The aim was to study the microbiological quality of Domiaty and Hungarian cheeses, molecular identification and biofilm formation of some selected contaminant bacteria. Samples were collected from two M and P big markets in Jeddah City through the period from February to October 2018, nine visits for two types of natural cheese. Results showed that the total bacterial counts (CFU/ml) from Domiaty cheese from two markets (M and P) were 0.1 x 105, 8 x 105 and 1 x 10 5 CFU/ml respectively (3 visits of M market) and 4 x 106, 0.4 x 106, 6.5 x 103, 1 x 103, 0.1 x 103 and 0.1 x 103 CFU/ml respectively (six samples from 6 visits from P market). Results showed that the total bacterial counts (CFU/ml) from Hungarian cheese were 1.5 x 10 5, 1x 10 4, 11 x 10 4 and 4 x10 6 CFU/ml respectively from (4 visits of M market) and 0.18 x 104, 3 x 106, 22 x 106, 6 x 106 and 5 x 104 CFU/ml respectively (5 visits from P market).Different bacterial isolates from cheese were identified by morphology and biochemical test. Bacterial isolates from cheeses were identified by VITEK MS as follow: Serratia liquefaciens (D6-1, D6-2, D14-1, D13-1 and D13-2), and Pseudomonas fluorescens (D14-2) were isolated from Domiaty cheese while Enterococcus faecium (H11-2), Serratia liquefaciens (H15-1) and Streptococcus thermophilus (H14-1) were isolated from Hungarian cheese. Some selected bacterial isolates were identified by 16S rRNA. Isolates were belong to MK757978 (Raoultilla terrigena (D15-1)), MK757979 (Bacillus cereus (D16-1)), MK757980 (Enterococcus faecalis (H10-2)), MK757982 (Enterococcus fiscalism (H11-1)), MK757981 (Serratia liquefactions (H13-1)), MK757984 (Anoxybacillus flavithermus (H17-1). All bacterial isolates have been tested for the formation of biofilm using a Tissue Culture Plate (TCP). Results revealed 12.5% and 46.15% of high biofilm formation respectively for bacterial isolates of Domiaty and Hungarian cheeses.
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