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pito's Content

There have been 10 items by pito (Search limited from 19-September 19)


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#194683 Thank you very much for the invitation

Posted by pito on 13 September 2020 - 08:03 AM in Free Stuff

Good luck.

Enjoy your stay here.




#194682 Weird images from algae culture

Posted by pito on 13 September 2020 - 07:58 AM in Microbiology

It looks like what you are seeing there are algal cells trapped by surface tension on the surface of the bubble/foam. The clearish object you can see in some of the pictures (e.g. at 10 o'clock position in image 3) looks like an interaction between the light-path and another bubble.

Yeah, that is what I also figured. 

I think it is indeed as you say, algal cells trapped in the fluid.




#194659 Weird images from algae culture

Posted by pito on 08 September 2020 - 12:46 PM in Microbiology

Which species of alga and scale?

Haha yes, I should have mentioned this.

It is a specials of chlorella and it is a 400X or 1000X image (middle one is 400X)




#194644 Weird images from algae culture

Posted by pito on 02 September 2020 - 12:10 PM in Microbiology

Hello all,

 

I recently grew some algea and took a few pictures of the foam visible in the culture.

I am wondering if I am simple seeing foam or a combination of foam and algae or ?

 

See pictures attached.

It looks like foam, but in some I can see something that looks like a nucleus. I am also wondering about the coloration. I guess the foam becomes green due to death algea?

 

thanks in advance.

Attached Thumbnails

  • l100.jpg
  • l1.jpg
  • schuim obj100x bis.jpg



#194302 Growth Curves for Yeasts and Molds

Posted by pito on 13 May 2020 - 01:08 AM in Microbiology

 

 

Hi all,

 

I recently attempted to Create growth curves for Candida Albicans and Penicillium rubens and have failed miserably, I'd like to share with you my protocol to see maybe I'm missing something:

  • I grew starter cultures in YM broth over a few nights(yeast culture was 2-3 days old, mold culture was 5-6 days old). I grew both cultures in a semi sealed sterile erlemmayer at room temperature placed on a rotating orbital shaker(spins in a cyrcle) at about 65 rpms. - I saw massive growth in both starter cultures.
  • I considered the grown starter cultures as 7 log (10,000,000 CFU/ml) concentration and I diluted both starters x4 and x5 and infected new samples (clean ym broth in erlenmeyer) at what I learned is considered 3 log and 2 log growth concentration.
  • I placed the 4 samples(2 for each fungi, at 2 different infection levels) on the same rotating shaker and started mesuring time - sampeling each bottle into 2 agar plates (my agar is oxytetracycline - glucose yeast extract agar) at 2 different dilutions (2 log and 3 log).
  • I sampeled the yeast samples every 3.5 hours, and diluted it another +1 ratio(1:10) each time considereing 3.5 hours is the average growth time for yeasts, for 7 times total.I sampeled the mold samples every 6 hours, and diluted it another +1 ratio(1:10) each time considereing 6 hours is the average growth time for molds , for 10 times total.
  • All plates were left for incubation in room temerature for 3 days (yeasts) and 5 days(molds).

Non of my mold plates showed any growth at all, and my yeast plates showed very random growth, showing some growth over the first few time points, then dropping to very low growth(with some plates showing 0 colonies) before going back to show some growth toward the end of the time points.

 

Please, if anyone has experience with growth curves or with growing these organisms, I'd appriciate any assistance you can offer.

 

 

 

 

Room temperature for C. albicans is too low for this experiment.

Not sure exactly where you got this protocol, but it is a bit weird.

3,5 hours is the average growth? At room temperature?

 

 

Thanks for getting back to me.

 

Why is room temp too low? I've had success growing C.albicans at it multiple times in the past, why would this experiment be different? wouldn't the lower temp just prolong my waiting time for plate results but in turn provide better selection conditions? 

 

The protocol is one I've used in the past to formulate growth curves for bacteria, L.Mono and Salmonella in particular, so the template is the same, with different growth and incubation time variables added. - if you have any insights into what I'm doing wrong, and you could provide an explanation as well, I will greatly appreciate it.

 

 

 

I am not saying you can't grow C. albicans at such low tempratures, what I am saying is that doing a growth curve at those temperatures is difficult.

 

As Phil Geis already mentioned: it is a fungus , 35°C is more appropriate and lets not forget: it is a human commensal. It is rarely found outside.

I am pretty sure you are even working with a strain that was collected from a  patient. Environmental C. albicans strains are rarely used in labs.

 

Also what Phil mentioned: not sure why you use plates with antibiotics.

 




#194276 Strains and Antibiograms

Posted by pito on 07 May 2020 - 09:47 AM in -Microbiology and Virology-

Can Gentamicin be provided for these 4 strains : P.aeruginosa, E.fecalis, S.aureus, B.subtilis ? I red that it's very effective on Pseudomonas and S.aureus but what about the other  ?

You just need to google it a bit...

I am not sure what exactly the problem is.

 

If you (like you mention) do not find the information on eg. wikipedia (meaning it is not a general resistance or susceptibility) than it is indeed not a typical trait. Of course: you can always find strains that have a resistance ...




#194275 Growth Curves for Yeasts and Molds

Posted by pito on 07 May 2020 - 09:38 AM in Microbiology

Hi all,

 

I recently attempted to Create growth curves for Candida Albicans and Penicillium rubens and have failed miserably, I'd like to share with you my protocol to see maybe I'm missing something:

  • I grew starter cultures in YM broth over a few nights(yeast culture was 2-3 days old, mold culture was 5-6 days old). I grew both cultures in a semi sealed sterile erlemmayer at room temperature placed on a rotating orbital shaker(spins in a cyrcle) at about 65 rpms. - I saw massive growth in both starter cultures.
  • I considered the grown starter cultures as 7 log (10,000,000 CFU/ml) concentration and I diluted both starters x4 and x5 and infected new samples (clean ym broth in erlenmeyer) at what I learned is considered 3 log and 2 log growth concentration.
  • I placed the 4 samples(2 for each fungi, at 2 different infection levels) on the same rotating shaker and started mesuring time - sampeling each bottle into 2 agar plates (my agar is oxytetracycline - glucose yeast extract agar) at 2 different dilutions (2 log and 3 log).
  • I sampeled the yeast samples every 3.5 hours, and diluted it another +1 ratio(1:10) each time considereing 3.5 hours is the average growth time for yeasts, for 7 times total.I sampeled the mold samples every 6 hours, and diluted it another +1 ratio(1:10) each time considereing 6 hours is the average growth time for molds , for 10 times total.
  • All plates were left for incubation in room temerature for 3 days (yeasts) and 5 days(molds).

Non of my mold plates showed any growth at all, and my yeast plates showed very random growth, showing some growth over the first few time points, then dropping to very low growth(with some plates showing 0 colonies) before going back to show some growth toward the end of the time points.

 

Please, if anyone has experience with growth curves or with growing these organisms, I'd appriciate any assistance you can offer.

 

 

 

 

Room temperature for C. albicans is too low for this experiment.

Not sure exactly where you got this protocol, but it is a bit weird.

3,5 hours is the average growth? At room temperature?




#194271 Terminology: chylotrophic

Posted by pito on 06 May 2020 - 10:40 PM in Microbiology

Suggest the term saprophytic betters described the fungal process.  Appears roots chylo (juice) and trophic (nutrition) drive in that direction.

 

How are you Pito?  Haven;t heard from you in a while.

Yeah, I guess that is a good way to describe it.

 

I never heard of it before, but I found it by accident in a PhD thesis and could not really find a lot of info about it.

 

To my surprise I now found the paper that originally coined the term!

I think it never caught up with scientist.

If you are curious: 

https://www.jstor.or...fo_tab_contents

and they describe it as:

 

1"Chylotrophic" is here introduced as a new word describing organisms which characteristically absorb organic food in solution instead of making or ingesting it. All saprobes and many parasites are chylotrophic.

 

 

 

 

Yeah, I have been busy (and changed jobs, I am in a completely different field now!) and the forum seems to have been pretty calm as well!

How are you?




#194067 Terminology: chylotrophic

Posted by pito on 18 April 2020 - 12:17 PM in Microbiology

Not commonly used, I consider myself fairly literate and didn't know the term

Yeah, I figured it is something hardly used.

 

Do you have an idea what they use? Or is there no term to describe "external digestion" in english?




#194007 Terminology: chylotrophic

Posted by pito on 17 April 2020 - 12:05 PM in Microbiology

Hello all,

 

is the term "chylotrophic" a commonly used one in English or not really?

It is a term to describe external digestion (as fungi for example do)

 

thanks in advance.





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