The Smallest Bacteria

http://www.madsci.org/posts/archives/2001-09/1001464156.Gb.r.html (2001)

Most bacteriology textbooks say Mycoplasma genitalium is the smallest known organism capable of independent growth and reproduction. Its size is given as 0.2 to 0.3 µm (micrometers). An average bacterium, like E. coli, is about 1 µm by 3 µm (it has a rod shape). A red blood cell is 8 µm in diameter and the average human cell is about 25 µm across.

Although mycoplasma can live in complex media in the laboratory, in nature they are always found living parasitically, attached to other cells. Since they take preformed nutrients from other cells, they have streamlined their metabolism and only have about 470 genes to use to make all the proteins needed for cell division, energy production, and protein synthesis, etc. These are the simplest cells found so far.

In 1990, Bob Folk at UT, using an electron microscope, observed 0.05 µm (50 nanometers) "nanobacteria" in rocks from hot springs. Nanobacteria were later found in blood, kidney stones, and in meteorites that came from Mars. Of course, this created quite a stir. But other researchers have not been able to find DNA or protein in nanobacteria, and it may be that the objects seen in the electron microscope are mineral microcrystals. Because of this, many experts doubt the existence of nanobacteria. But, supporters continue looking for evidence that nanobacteria are living.

A theoretical discussion of what could be the smallest bacterium possible gives a diameter of 0.17 µm. This figure also precludes the possibility of nanobacteria.

~Since nanobacteria can't be proven its existence yet, i guess Mycoplasma's d smallest bacteria at d moment.. :P~

Biggest Known Bacteria

Thiomargarita namibiensis

Thiomargarita namibiensis is a very unique bacteria because not only does it live where most bacteria can not survive it is the largest bacteria ever found. It took the record of the largest bacteria from Epulopiscium fishelsoni by being one hundred times larger. These prokaryotic, spherical bacteria are about 0.75 millimeters in diameter, which allows it to be visible by the naked eye. It is generally found in chains of ten or more. It is also very easy to notice because it shines like a pearl. The pearl color gives it the name “Sulfur Pearl of Namibia”. The rest of its name comes from the fact that it eats sulfur and that it was found off of the coast of Namibia. The analogy is this:

1. Any normal bacterium is likened to a new-born mouse

2. The previous largest bacteria, Epulopiscium fishelsoni, is likened to a lion

3. The newly found Thiomargarita is likened to a BLUE WHALE!! (wow!)

Guyz, check out http://web.mst.edu/~microbio/BIO221_2005/T_namibiensis.htm or http://www.sciencenews.org/sn_arc99/4_17_99/fob5.htm if you wan more details.. :) i'm still trying to figure out which is the smallest bacteria.. there are studies suggesting nanobacteria but then there are also people refuting it..

Semester 3 Timetable !!

The timetable has just been finalized today. I’m so sorry for any inconvenience caused. Anyway, I'll be sending those timetables to all your email addresses. Everyone can also find it under the I-Drive (under the Timetable folder-> under semester 3)

Please take note that your class will begin on
Tuesday, 11 Nov 2008 at 9.00am to 12.45pm,
Wed - Fri, 12 - 14 Nov, from 10.30am-12.45pm.

There is no afternoon class on 11-13 Nov, while on Friday, 14 Nov the afternoon class will start from 2.45pm-4.45pm.

Thanks and Happy holiday
Jee Chung

Announcement

Prof Andrew Schelling (our external examiner from New Zealand for the next EOS2) will be giving a seminar on "Direct to Consumer Marketing of Genetic Testing" on 6th November 2008 at Auditorium A from 4.00 - 5.00 p.m. This is part of our effort to maximise the expertise of external examiners while they are here.

Kindly confirm your participation with Catherine, CtME.