Hi there,

I think Nikita and Deepti both have good points. Slopes have a much better (lower) surface area to volume ratio meaning the medium is not accessed as rapidly as plates, also the screw on caps (McCartney bottles) are airtight and prevent loss of moisture. That being said slopes should be routinely subcultured on average every 3 months, but this may vary with growth rates of the particular isolates eg Vibrios maybe fortnightly, Mycobacteria 6 monthly or longer. Another practical point is that slopes are better for long term storage as they occupy a lot less space!!

cheers,

Richard

Agar slopes are more preferred way for preservation of microorganisms because of following reasons:-

1. Since the slopes are normally made in the test tubes the chances of contamination was less as compared to plates (due to less area being exposed every time).

2. Slopes are better than plates in terms of storage space and media consumption as well.

However I would suggest that for long terms storage go for Glycerol Stock preparation as they can be stored for long duration for 1-3 years (depending on % glycerol Stock) and can be readily preserved at -65 to -80 degree Celsius without any loss in cell viability . Whereas in case of Agar Slopes the storage duration doesnot exceed 6-9 months and for plates 4-6 months. You need to do sub-culturing invariably when agar is used for preservation of microbes.

I agree with Deepti on the above answer, also since the surface area of the slope is less, the drying of the media is delayed, as compared to the agar plates where a huge exposed area makes it more prone to drying and hence unfit for long term storage.

Apart from making glycerol stocks, you can make slopes and seal them with paraffin. This can be an easy way for short term storage.

Hi there,

I think Nikita and Deepti both have good points. Slopes have a much better (lower) surface area to volume ratio meaning the medium is not accessed as rapidly as plates, also the screw on caps (McCartney bottles) are airtight and prevent loss of moisture. That being said slopes should be routinely subcultured on average every 3 months, but this may vary with growth rates of the particular isolates eg Vibrios maybe fortnightly, Mycobacteria 6 monthly or longer. Another practical point is that slopes are better for long term storage as they occupy a lot less space!!

cheers,

Richard

Thanks to all of you! For your best comments.

Hi...............

Every one pointed out good points.

Slants are better suited than agar plates, because they can be capped, preventing the agar and the culture from drying out. The cap also prevents airborne contaminants from entering the slant. Also, slants take up less storage space than an agar plate.U can go for cryopreservation.

Slant media with its smaller surface area allow lesser cells to grow, thus the consumption of the nutrient is lesser, therefore, it can keep longer as compared to those culture on plate. And also, the petri dish is not design for cold storage, it will crack after prolonged storage, however, glassware for slant storage can overcome this problem. Just my little thoughts, hope it helps

Yes it helps of course. Thank you for your valuable ideas

Mainly because of less surface area in slants leads to reduction in evaporation of moisture, finally long term availability of media is achievable in slants compared to plates.

Good handling practices leave no space for contamination, otherwise even tubes get contaminated as whole inoculating loop is required to be put in tube. New students often find it difficult to handle tubes, caps and loop simultaneously than plates.

one more addition.

you can try slants with larger butt (bottom portion, other than slanting part), it can give longer time period to preserve your cultures.

can I use slant Mueller Hinton agar tubes for bacteria storage?

Hello Sebahat Özakça Öztekin

Agar slants are better for long term storage

Hi ,

Above all points regarding culture tubes is good . Thank you to all .

Does any one have experience of shipping agar slants? temperature? duration? Classification Cat A? or Cat B?

Dear Sureyah, you can seal your slant tubes from the cap by using parafilm. To prevent the tubes from breaking, soft bag may work for you. For short time travels, I think temperature fluctuation has no effect on the cultures once they've grown up. CAT B will be suitable for shipping biological samples. Here is the link that explains shipping classifications.https://www.ups.com/us/en/help-center/packaging-and-supplies/special-care-shipments/hazardous-materials/biological-substances.page

Good luck in your study!

these agar slants of Ecoli need to move from UK to east africa and this will take about 3days. Shouldnt we maintain these at fridge temperature all through transit?

sureyah

I think, plate or an agar slant at room temperature will be suitable for your culture for several days. There is no need to keep them at +4C. When it reaches you, you can revive them by inoculating into TSB broth or Nutrient Broth, then prepare glycerol stocks and store at -80C for longterm (years)

Sebahat