Latest News

About 35,000 people die from drug-resistant infection in the US. What are we going to do?
When antibiotics first achieved widescale use in the middle of the 20th century, they had a tremendous impact. For example, the mortality rate in England from infectious disease dropped from 25% in 1…
Read more
Nasal nanoSTING vaccines may Provide Lasting Protection Against SARS-CoV-2
All successful vaccines against SARS-CoV-2 have used the spike protein as the target and delivered the vaccine by intramuscular injection, typically a shot in the left or right shoulder. The vaccines…
Read more
Probiotic Bacterium can prevent antibiotic use side effects
Researchers at the University of Maryland School of Medicine demonstrate the power of probiotics. A test group was given Bifidobacterium lactis BB-12 as they took a course of amoxicillin clavula…
Read more
The CDC publishes another study that shows the protection that vaccination provides against COVID-19
The CDC is out with another recent study comparing the incidence rate of COVID-19 in unvaccinated vs. vaccinated individuals. It is mostly good news. The vaccine protects against infection, hospitali…
Read more
No, that is NOT what the study says -- Immunity to COVID
I am getting tired of the scare tactics that news and media sources are using to get you to click on headlines. Headlines in some press releases drive me bananas: New study: Nursing home residents,…
Read more

3-1 Introduction

( 33422 Reads)

| | |

Microorganisms typically face the world as single cells rather than the multi-cellular assemblies of higher organisms. Therefore, each cell must contain all the structures necessary for managing its internal state and dealing with the outside environment. Not surprisingly, this evolutionary process results in similar structures and processes to solve similar needs in different microorganisms. However, prokaryotes have been on this earth for a long time, and this has allowed them to differentiate into a dizzying number of different species. Eukaryotic microbes are not quite so diverse, but they still display a remarkable range of properties. No one cell contains all the structures that we describe here, but we will explore the more common structures (Figure 3.1) observed by scientists in the past 150 years. A distinction in this discussion must be made between the two types of prokaryotes: the Archaea and their cousins, the Bacteria. We will initially focus on Bacteria since we know the most about them. Many of the structures we will examine are present in Bacteria and Archaea, but there are significant differences. We will cover these at the end of the chapter. Finally, we will talk about the features that are distinctive among the microbial eukaryotes.

The Generalized Bacteria

Figure 3.1. The Generalized Bacteria. This cartoon displays many of the common structure found in prokaryotic microorganisms, though not every one will have every one of these structures.

So how did scientists find out so much about such tiny organisms? As you might guess, many techniques come into play when tackling a subject as complex as bacterial structure. Microscopes help scientists visualize the location of structures and how they are arranged spatially in the microbe. Bacterial genetics and molecular biology identify and analyze the genes necessary for the synthesis and regulation of these structures. Biochemistry permits the detailed examination of each part separately, with implications for its role in the living bacterium. The powerful combination of these disciplines provides a deep understanding of how a bacterium is put together, but there is still much to learn.

| | |