جستجوی مقالات مرتبط با کلیدواژه "bacillus" در نشریات گروه "محیط زیست"

In Thailand, bacterial wilt is one of the most severe diseases that affects pathumma, also known as Curcuma alismatifolia Gagnep. Biological control was proposed to control this disease with antagonistic bacteria. The current study was conducted to screen for antagonistic microorganisms capable of inhibiting the pathogenic bacteria and to evaluate the beneficial effect of antagonistic bacteria on pathumma in vivo. Antagonistic bacteria were isolated from soil samples obtained from several locations in Thailand and screened for antibacterial activity. Next, the optimal conditions for the growth of antagonistic bacteria were determined. The production of anibacterial substances were then characterized. The potential of antagonistic bacteria to reduce the growth of plant pathogens was evaluated under greenhouse conditions.      In total, 102 bacterial isolates were isolated using tryptic soy medium.  After evaluating their capacity to inhibit the growth of the wilt-causing bacteria using the paper disc diffusion assay, it was found that three bacterial isolates, Bacillus subtilis SP15, Pseudomonas mosselii SP38, and Pseudomonas mosselii SP46 showed high ability to inhibit growth of the wilt-causing bacteria Enterobacter asburiae JK1, JK2, JK3, JK4, E. dissolvens JK5 and E. hormachei JK6. The optimal conditions for all antagonistic bacterial isolates were 25 or 30 degrees Celcius, at potential of hydrogen 7-8 in modified tryptic soy medium containing 0.5 percent (weight /volume) glucose or sucrose and 1.5 or 2 percent (weight/volume) peptone.  The antagonists were able to produce siderophores and phenazines.  Under greenhouse experiments, the mixed cultures of antagonistic bacterial isolates could reduce the wilt disease incidence, and the number of pathogenic bacteria declined compared with the diseased control plants. In addition, it was discovered that soil materials provided the best carrier materials for the successful formulation of the mixed culture of antagonistic bacteria. This study revealed that the selected antagonists were beneficial for controlling wilt disease in pathumma. This is the first scientific study on the control of wilt-disease causing Enterobacter spp. in C. alismatifolia Gagnep. in Thailand using antagonistic bacteria. It is expected that these antagonistic bacteria be useful in wilt disease management in the field for friendly and sustainable agriculture

Surface waters such as lakes and rivers which are multipurpose fields used for drinking water supply, agricultural irrigation, fisheries and energy production are being threatened by domestic, industrial and agricultural pollution caused by rapidly growing population. Due to the insufficient numbers of studies on Lake Bafa, the largest coastal lake of Turkey, this study was conducted to investigate some physico-chemical properties of the lake’s water and levels of fecal indicator bacteria in it. Additionally, bacteria species isolated from sediments that could be cultured and their heavy metal (Cu, Zn, Ni, Cr, Hg) and antibiotic resistance were determined. Levels of fecal coliforms (FC) and fecal streptococci (FS) were determined through membrane-filtration techniques. While fecal coliform levels detected in the three sampling stations were above the limit value, fecal streptococci levels were below the limit value. Seventeen isolates identified through the 16S rDNA analysis were determined to be the members of the genus Bacillus and Arthrobacter. The resistance displayed by the isolates to heavy metals was in the following order: Cu> Zn> Ni> Cr> Hg. The isolates were also resistant to ampicillin and tetracycline. The results of this preliminary study suggest that the lake which serves agriculture, fishing and recreation purposes should be regularly monitored in terms of public health.

The main objective of this study was to determine the effects of biofertilizers on quantity and quality of essential oil of basil essential oil content, geranial, caryophyllene, caryophyllene oxide and methyl chavicol in essential oil. The experiment was carried out as randomized complete blocks design with eight treatments and three replications at research field of Agriculture Company of Ran in Firouzkuh of iran in 2012 . The treatments were [1] Azotobacter chroococcum (A), [2] Azospirillum lipoferum (B), [3] Bacillus circulans (C), [4] A + B, [5] A + C, [6] B + C, [7] A + B + C and [8] control (without fertilizer application). The present results have shown that the highest essential oil content and the minimum caryophyllene oxide in essential oil were obtained after applying each three bioertilizers (A + B + C). The maximum geranial in essential oil and the minimum caryophyllene in essential oil were obtained by using two biofertilizers (A + C). Also, the highest methyl chavicol in essential oil was obtained after applying two biofertilizers (B + C).

The main objective of this study was to determine the effects of plant growth promoter bacteria on biomass and yield of basil. The experiment was carried out as randomized complete blocks design with eight treatments and three replications at research field of Agriculture Company of Ran in Firouzkuh of iran in 2012 . The treatments were [1] Azotobacter chroococcum (A), [2] Azospirillum lipoferum (B), [3] Bacillus circulans (C), [4] A + B, [5] A + C, [6] B + C, [7] A + B + C and [8] control (without fertilizer application). The present results have shown that the highest dry weight of plant, herb fresh yield, herb dry yield and essential oil yield were obtained after applying each three bacteria (A + B + C). The maximum plant height was obtained by using two bacteria (A + B). Generally, the maximum herb dry yield and essential oil yield were obtained with the integrated application of each three bacteria.