e-portfolio teknik asas mikrobiologi (third week)

Experiment 2
In this week,I learn the techniques for isolation of pure cultures.The techniques commonly used for isolation of discrete colonies require that the number of organisms in the inoculum be reduced.I learn how to do streak-plate and spread-plate to isolate a single colony.The streak-plate method is a rapid qualitative isolation method.It involves using the principle of dilusion where I am able to get single colony of two type of mixed culture at the end.It is essentially dilution techniques that involve spreading a loopful of culture over the surface of an agar plate.There are two types  of streak-plate technique,four ways streak-plate technique  and alternate streak-plate method.

Four ways streak-plate technique

Alternate streak-plate technique

All the streak-plate method involves streaking in four quadrant.To streak from the third quadrant to the fourth quadrant,we do not need to flame the loop again because the culture at third quadrant is dilute enough where I streak to fourth quadrant,I manage to get a single colony.

I did streak-plate to isolate S.marcescens and S.aureus from the mixed culture of both bacteria.I also did streak-plate for the mixed culture of S.aureus and E.coli. However, I was unsuccessful in doing this experiment because it was the first time I learn about this and I use the wrong spreading techniques though I was able to get single colony at the end of bacteria.I hope I can improve my streaking technique better in the next experiment.

Streak-plate of the mixed culture of  S.marcescens and S.aureus

Streak-plate of the mixed culture of S.aureus and E.coli

In experiment 2,I also learnt to collect specimen using cotton swab from the female toilet basin and put it into Bijou bottle containing sterile water.We did both streak-plate and spread-plate techniques for the environmental sample we collected.

Streak-plate of the environmental sample

Spread-plate of the environmental sample

In part B of the experiment,we isolate the single colony from streak-plate or spread-plate and spread it to four different agar slant.

Experiment 3

In this experiment,I learnt about the cultural characterisctics of microorganisms.These cultural characteristics are used as a basis for separaring microorganisms into taxonomic groups.They are determined by culturing the organisms on nutrient agar slants and plates,in nutrient broth,and in nutrient gelatin.

These is how we differentiate and determine the cultural characterisctic of the bacteria.

In the nutrient agar slant,we used single straight line of inoculation on the surface instead of using zig-zag pattern to observe the growing pattern of the bacteria.We transfer the M.luteus,P.aeruginosa,M.smegmatis,E.coli and B.sereus to the nutrient agar slant,nutrient agar plates ,nutrient broth cultures and nutrient gelatin using the aseptic techniques.

nutrient agar slant culture

nutrient agar plates

nutrient broth culturs

nutrient gelatin

E-portfolio microbiology basic techniques (week 2)

E-portfolio (Teknik asas mikrobiologi)

This week I have learnt the culture transfer techniques.Microorganisms  are transferred from one medium to another medium to another by subculturing.I have learnt the proper aseptic techniques which its aim to reduce the contamination from the environment to the culture.I learnt that there are three cultures medium which are the  broth,agar slant and agar deep.I also learn about the material and apparatus used like Bijou bottle,micropipette,bacteriological tube,autoclave which  are used to sterilize equipment and supplies by subjecting them to high-pressure saturated steam at 121 °C (249 °F) for around 15–20 minutes and inoculating needles or loop.We transfer the bacteria (Serratia marcescens) ,broth culture “A” and broth culture “B” to agar slant,agar deep and broth.The culture “B” are used as the control of this experiment.The transfer of culture “A”  and Serratia marcescens to the agar slant deep and broth produced a positive results.I have also learnt to label the apparatus properly.

from Serratia marcescens to nutrient medium

from culture B to nutrient medium

from culture "A" to nutrient medium