Is rhizobacteria Gram positive or negative?
Of 51 (PCR-RFLP and 16S rRNA gene) rhizobacterial isolates characterized, 18 (16 Gram-negative and 2 Gram-positive) strains belonging to different RFLP groups were assessed for the production of IAA and utilization of ACC as their sole nitrogen source.
How do you isolate rhizobacteria?
For isolation of bacteria, 2–5 g of fresh roots were washed under running tap water and surface sterilized in 5% NaOCl for 1 min. After washing three times with sterilized distilled water (SDW), the root samples were ground with a sterilized mortar and pestle.
How do you count microbes under a microscope?
The most direct method of counting microorganism is by the use of a microscope and a slide with special chambers of known volume. These slides allow the counting of a small number of cells in a small volume and extrapolating the result to determine the population.
What is used to visualize microorganisms?
While light microscopes are valuable, it is sometimes desirable to view living microorganisms, for example to observe their chemotactic behavior. A phase contrast microscope is an excellent tool for these types of observations.
How do Rhizobacteria help plants?
Rhizobacteria, through nitrogen fixation, are able to convert gaseous nitrogen (N2) to ammonia (NH3) making it an available nutrient to the host plant which can support and enhance plant growth.
What is rhizosphere effect?
Rhizosphere effects (REs) are defined as biological, chemical, and physical changes in soils that occur because of root exudates and rhizodeposition2,3. Biological processes are related to the parasitism of host plant microorganisms that promote nutrient and water uptake from soils2.
Is Rhizobacteria aerobic?
Nitrogenase is an enzyme involved in nitrogen fixation and requires anaerobic conditions. Membranes within root nodules are able to provide these conditions. The rhizobacteria require oxygen to metabolize, so oxygen is provided by a hemoglobin protein called leghemoglobin which is produced within the nodules.
How do you isolate Pgpr from soil?
Isolation of PGPR strains: Ten gram rhizosphere soil was taken in 250 mL Erlenmeyer flask containing 90 mL sterile distilled water and mixed by shaking for 15 min. Serial dilutions were done in sterile distilled water. The dilution was done up to 10-2 to 10-6.
How do you count cells on a microscope?
Using a microscope, focus on the grid lines of the counting area with a 5-10x objective. Count the cells in one set of 16 squares (1×1 mm square area; the blue area). You should set a counting rule. To calculate the number of cells per mL: Take the average cell count from each of the sets of 16 corner squares.
How do you count bacterial cells?
Calculate the number of bacteria (CFU) per milliliter or gram of sample by dividing the number of colonies by the dilution factor multiplied by the amount of specimen added to liquefied agar.
What kind of microscope can see bacteria?
On the other hand, compound microscopes are best for looking at all types of microbes down to bacteria. Some, however, are better than others. The magnification for most compound microscopes will be up to 1000X to 2500X.
Can digital microscope see bacteria?
Re: USB digital microscope With a very basic compound microscope, I have seen bacteria at as low as 400x as dark silhouettes, and I was able to make out their shape: spiral, coccus etc. So even though magnification is important, the correct optical configuration is critical.