Introduction to Microbes and Their Building

Blocks: An Introduction

Chapter 1

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1000 unidades

(1 m)

1000000 unidades

(1nm)

1um (1000 nm)

1 m

(10-100nm) (10 m)

Microbes: Tiny But Mighty •Microbiology deals with living things too small to be seen without magnification

•Microorganisms include - bacteria

- algae

- protozoa

- Helminths

2011

10-08-12

01-03-13

08-29-12

25 days

hospitalized

Do not underestimate the power of a Microbe!!!

Do not underestimate the power of a Microbe!!!

It can Kill YOU!

Viruses

•Viruses can infect all living cells, but are not alive themselves

•Viruses are - parasitic - protein-coated genetic elements - dependent on their infected host - connected with the evolution of microbes and

humans

Could a bacteria be infected by a virus?

How about a virus?

Guinea has reported some 396 cases and 280 deaths (71%)

Sierra Leone has 176 cases and 46 deaths (26%)

Liberia reports 63 cases and 41 deaths. (65%)

Ebola 2014

http://www.who.int/mediacentre/news/notes/2014/ebola-response/en/

Características de los seres vivientes :enfoque en Bacterias

1. metabolismo

2. Crecimiento y reproducción

4. Comunicación

3. Diferenciación

5. Movimiento

6.Evolución

• mutaciones

• perdida de material genético

existente o adquisición

de material genético exógeno

The Nature of Microorganisms •Microbes are very easy and very difficult to study

- reproduce rapidly

- can be quickly grown in large populations in the laboratory

- can’t be seen directly, but we can predict their presence using our senses! Only in special occasions.

Evolutionary Timeline Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Humans

Mammals

Reptiles

Insects

Eukaryotes

1 billion

years ago

2 billion

years ago

3 billion

years ago

4 billion

years ago

Prokaryotes

Probable origin of earth

Present

time

NASA GSFC image by Robert Simmon and Reto Stöckli

Microbes and the Planet (cont’d) •Microbes are ubiquitous

- found in the Earth’s crust, polar ice caps, oceans, and the bodies of plants and animals

- occur in large numbers

- live in places where other organisms cannot survive

Microbial community of in a hypersaline

pond, San Salvador Island, Bahamas

Microbes and the Planet (cont’d)

•Evolution - the accumulation of changes that occur in organisms as they adapt to their environments

•The Theory of Evolution - documented every day in all corners of the planet

- observable phenomenon testable by science

- has undergone years of testing and has not been disproven

- a label for a well-studied and well-established natural phenomenon

Wielgoss, S., J. E. Barrick, O. Tenaillon, M.

J. Wiser, W. J. Dittmar, S. Cruveiller, B.

Chane-Woon-Ming, C. Médigue, R. E.

Lenski, and D. Schneider. 2013. Mutation

rate dynamics in a bacterial population

reflect tension between adaptation and

genetic load. Proceedings of the National

Academy of Sciences, USA 110:222-227.

Richard E. Lenski

Hannah Distinguished Professor

Michigan State University

Email: lenski@msu.edu

http://myxo.css.msu.edu/

How Microbes Shape Our Planet

•Anoxygenic photosynthesis

- Light-fueled conversion of carbon dioxide to organic material that does not produce oxygen

•Oxygenic photosynthesis

- Light-fueled conversion of carbon dioxide to organic material that does produce oxygen

- the source of oxygen on the planet

- lead to the use of oxygen for aerobic respiration

- photosynthetic microorganisms account for 70% of the Earth’s photosynthesis

How Microbes Shape Our Planet

Microbes Harming Humans

•The majority of microorganisms that associate with humans cause no harm •Pathogens: microbes that cause disease •The World Health Organization (WHO) estimates that there are 10 billion new infections caused every year by microbes •Infectious diseases are among the most common cause of death in the U.S. and worldwide •The death toll from infectious diseases is approximately 13 million people per year worldwide •The CDC reports that a child dies from malaria every 30 seconds

Top Causes of Death

horas

días Como surge esta vida?

Fenómenos observados por el hombre sin explicación..

Teoría de la generación espontánea: Origen de la vida de objetos no vivientes.

Promulgada por Aristóteles (384-322 B.C.) y aceptada por mas de 1900 años.

Francesco Redi (1629- 1697)

Demostrando que las larvas provienen de las moscas y no de la carne!!

Historia de la Microbiología: rutas de descubrimiento

Antoni van Leeuwenhoek (1684) : primero en observar una bacteria y

describir las células rojas de la sangre

“…tho my teeth are keep usually very clean, nevertheless when I view them in a

magnifying glass, I find growing between them little white matter as thick as wetted

flower: in this substance tho I do not perceive any motion, I judged there might

probably be living Creatures...”

Philosophical Transactions of the Royal Society of London 14(159):568-574 [May 20, 1684].

generación espontánea: En microorganismos?

John T. Needham (1713-1781)

Varios

días

Lazzaro Spallanzani (1729-1799)

Varios

días

sellada

Lazzaro Spallanzani (1729-1799)

Concluye lo siguiente:

1) Needham no sello las botellas herméticamente bien o no las calentó

lo suficiente.

2) Existen microorganismos en el aire y pueden contaminar experimentos.

3) La generación espontánea de microorganismos no existe, todos los seres

vivos surgen de otros seres vivos.

Esto no fue suficiente.. 1) demasiado calor y destruyo la “fuerza de la vida”

2) No permitió que entrara el aire esencial para la vida.

Historia de la Microbiología: rutas de descubrimiento

Louis Pasteur (1822- 1895): prueba que la teoría de generación espontánea es

incorrecta, técnicas de esterilización, vacunas, fermentación, teoría del germen

de enfermedad..

Eduard Buchner (1860-1917)

La fermentación alcohólica puede llevarse acabo sin células vivas

Solo con la presencia de enzimas. Su trabajo da origen a la bioquímica.

Fig. 1.15

sellado

No fermentación

sellado

fermentación

levadura

Historia de la Microbiología: rutas de

descubrimiento

Robert Koch (1843-1910): prueba que los

microorganismos pueden causar

enfermedades (teoría del germen de la

enfermedad),

•catapulta el desarrollo de la microbiología.

Bacillus anthracis

Postulados de Kock

Descubrimiento

de Mycobacterium

tuberculosis

Ignaz Semmelweis (1818-1865)

Joseph Lister (1827-1912)

phenol Heridas, cirugías, gasas, etc.

Observar, hipótesis, experimento, resultados

Mortandad de 18.3% a 1.3%

Florence Nightingale (1820-1910)

Documento e implemento reglas de limpieza en los hospitales.

Además fundo la primera escuela de enfermería.

Libro: Notes on nursing (1859) by Florence Nightingale

Biblioteca UPRM: RT40 .N5 1992 C.1

En circulación

John Snow (1813-1858)

Documento los casos de cólera e hipotetizo

Que estos se debían al agua contaminada

Otras personas importantes:

Albert Neisser

Shibasaburo Kitasato

Kiyoshi Shiga

Martinus Beijerinck

Alexandre Yersin

Edward Jenner

Alexander Flemming

Que hicieron? Cual fue su contribución? Esta es su asignación para la próxima clase!

Descubrimiento e

inicio: Microbiologia

Medica y General

Era de la Biologia Molecular y

la Microbiologia General

Microbiologia Molecular,

Genomica y Proteomica

Nursing

tamaño de una bacteria comparable al de organelos como el mitocondrio,

cloroplastos e hidrogenosomas

Five Types of Microorganisms

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Fungus

Human hair

Bacterium

Virus

200 nm

Fungus:

Syncephalastrum

Bacterium:

E. coli

Helminth: Head (scolex)

of Taenia solium

Protozoan:

Vorticella

Bacteria

Helminth is visible

to the naked eye.

Protozoan

Fungus

Red blood

cell

20 microns

Virus:

Herpes simplex

A single

virus particle

(taenia, herpes): Centers for Disease Control; (vorticella ): © Carolina Biological Supply/Phototake; (e. coli): CDC/Janice Haney Carr;

(syncephalastrum): © Dr. Arthur Siegelman/Visuals Unlimited

Macromolecules: Superstructures of Life •Macromolecules: very large molecules •Four main macromolecules

- carbohydrates

- lipids

- proteins

- nucleic acids

•Monomers: subunits of macromolecules •Polymers: chains of various lengths made up of monomers

Macromolecules and Their Functions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Table 1.3 Macromolecules and Their Functions

Notes About the Examples Examples Macromolecule Description/Basic Structure

Carbohydrates

Monosaccharides

Disaccharide

Polysaccharides Chains of monosaccharides

Two monosaccharides

3- to 7-carbon sugars Glucose, fructose

Major component of cell membranes; storage

Nucleic acids

Proteins

Ribonucleic acid

(RNA)

Deoxyribonucleic

acid (DNA)

Lipids

Fatty acids + glycerol

Fatty acids + glycerol + phosphate

Fatty acids, alcohols

Ringed structure

Cell wall of mycobacteria

In membranes of eukaryotes and some bacteria

Sugars involved in metabolic reactions; building

block of disaccharides and polysaccharides

Composed of two glucoses; an important breakdown

product of starch

Composed of glucose and galactose

Composed of glucose and fructose

Cell wall, food storage

Maltose(maltsugar)

Lactose (milk sugar)

Sucrose (table sugar)

Starch, cellulose, glycogen

Fats, oils

Membrane components

Mycolic acid

Cholesterol, ergosterol

Chains of amino acids

Pentose sugar + phosphate

+ nitrogenous base

Purines: adenine, guanine

Pyrimidines: cytosine, thymine,

uracil

Contains deoxyribose sugar and

thymine, not uracil

Contains ribose sugar and uracil,

not thymine

Chromosomes; genetic material of

viruses

Ribosomes; mRNA, tRNA, small

RNAs, genetic material of viruses

Facilitate expression of genetic traits

Mediate inheritance

Serve as structural components and perform

metabolic reactions

Enzymes; part of cell membrane, cell

wall, ribosomes, antibodies

Triglycerides

Phospholipids

Waxes

Steroids

Polysaccharides •Contribute to structural support and protection •Serve as nutrient and energy stores •Cellulose: found in plants and algae •Agar: polysaccharide used in preparing solid culture media for microbes •Peptidoglycan: polysaccharides linked to peptide fragments; found in bacterial cell walls •Lipopolysaccharide: complex of lipid and polysaccharide responsible for symptoms of fever and shock •Glycocalyx: outer surface of many cells; functions in attachment or as a receptor that receives external stimuli

Lipids: Fats, Phospholipids, and Waxes

•Triglycerides: storage lipid including fats and oils •Glycerol: 3-carbon alcohol with 3 OH groups that serve as binding sites •Fatty acids: long-chain hydrocarbon molecules with a carboxyl group (COOH) that binds with glycerol

- saturated fatty acids: solid at room temperature

- unsaturated fatty acids: liquid at room temperature

•In most cells, tryglycerides are stored in long-term concentrated form as droplets or globules

(b)

Fatty Acids

(1) Palmitic acid, a

saturated fatty acid

(2) Linolenic acid, an

unsaturated fatty acid

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

H H

H H

H H

H H

H H

H H

H H

H H

H H

H H

H H

H H

H H

H H

H

C H H

O HO O

C

C

C

C

C

C

C

C

H H

H H

H

H

H H

H

H

H

C

H

H

H

H

HO

b(right): © Stockbyte/PunchStock (RF)

C

C

C

C

C

C

C

O

H H

H H

H H

H H

H H

H H

C

C

C

C

C

C

C

O

H H

H H

H H

H H

H H

H H

C

C

C

C

C

C

C

O

H H

H H

H H

H H

H H

H H

C H C

H

H C

H H

+

C H C

H

H C

H H

O

O C

R

O

O C

R

O

O C

R

s 3

Triglyceride

H2O

HO HO HO

OH OH OH

Fatty Acids Triglycerides

Ester

bond

Hydrocarbon

chain

(a)

Fatty

acid

Carboxylic

acid

Glycerol

R hydrocarbon

chain

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Membrane Lipids •Hydrophilic (“water-loving”) region from the charge on the phosphoric acid-alcohol “head” of the molecule •Hydrophobic (“water-fearing”) region in the long, uncharged “tail” of the molecule formed by fatty acids

O C C

O O

H

H

O

O

P O O

R

O

Variable alcohol group

Polar lipid molecule

(a)

Phosphate

polar head

(b)

Water Water

(2) Phospholipid bilayer

Glycerol

Water

(1) Phospholipids in single layer

Charged

head

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HCH

HC

HCH

CH

Fatty

acids

Nonpolar

tails

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View of a Membrane Bilayer of Lipids

H C

C

C C

Cell

membrane

Protein

Cholesterol

Glycolipid

Phospholipids

Site for

ester bond

with a fatty

acid

Cholesterol

HO

CH2

CH2

CH2

CH2

CH

CH3 CH3

CH

H2C C

H2C

CH3

CH3

CH3 CH

CH

HC

HC CH

H2C

H2

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Steroids and Waxes •Steroids: complex ringed compounds commonly found in cell membranes and animal hormones

- cholesterol: reinforces the structure of the cell membrane in animal cells and mycoplasmas

•Waxes: esters formed between a long-chain alcohol and a saturated fatty acid

- fur, feathers, fruits, leaves, human skin, and insect exoskeletons are naturally waterproofed with waxes

- bacteria that cause tuberculosis and leprosy contain a unique wax in their cell wall that contributes to their pathogenicity

Proteins •Predominant organic molecule in cells •Amino acids: building blocks of proteins •Peptide: a molecule composed of short chains of amino acids •Polypeptide: contains an unspecified number of amino acids but usually has more than 20 and is often a smaller subunit of a protein

Protein Structure and Diversity •Primary structure (1°): the type, number, and order of amino acids in the chain •Secondary structure (2°): arises when functional groups exposed on the outer surface of the molecule interact by forming hydrogen bonds

- alpha helix

- beta-pleated sheet

•Tertiary structure (3°): created by additional bonds between functional groups •Quaternary structure (4°): formed when more than one polypeptide forms a large, multiunit protein

Stages in the Formation of a Functioning Protein

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Beta-pleated sheet Random coil Alpha helix

Secondary Structure

(b)

Primary Structure

(a)

Amino acid

sequence

Tertiary Structure

(d)

Quaternary Structure

Alpha helix

Folded polypeptide chain

Two or more

polypeptide chains

Lys

Ph

e

(c)

Protein Bonding and Folding

•Each protein develops a unique shape with a distinctive surface pattern •Creates a functional diversity required for thousands of cellular activities •Enzymes: protein catalysts for chemical reactions in cells •Antibodies: complex glycoproteins with specific attachment regions for bacteria, viruses, and other microorganisms •Native state: the functional three-dimensional form of a protein •A protein becomes denatured if the •protein structure is disrupted for some •reason

The Nucleic Acids: A Cell Computer and Its Programs •DNA: contains the special coded genetic program with detailed and specific instructions for each organism’s heredity •RNA: “helper” molecules responsible for carrying out DNA’s instructions and translating the DNA program into proteins

The Double Helix of DNA •Formed by two very long polynucleotide strands linked by hydrogen bonds between complementary pairs of nitrogen bases •Adenine pairs with thymine •Guanine pairs with cytosine

RNA: Organizers of Protein Synthesis •Often a long, single strand of nucleotides •Contains ribose instead of deoxyribose and uracil instead of thymine •Three major types:

- messenger RNA (mRNA)

- ribosomal RNA (rRNA)

- transfer RNA (tRNA)

.

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

A T

C G

G C

T A

A T

C G

U

A

C

G

C

A

D

D

D

D

D

D

D

D

D

D

D

D

R

R

R

R

R

R

(a) A nucleotide, composed of

a phosphate, a pentose

sugar, and a nitrogen base

(either A, T, C, G, or U) is

the monomer of both DNA

and RNA.

DNA

(b) In DNA, the polymer is composed

of alternating deoxyribose (D) and

phosphate (P) with nitrogen bases

(A,T,C,G) attached to the deoxyribose.

DNA almost always exists in pairs of

strands, oriented so that the bases

are paired across the central axis of

the molecule.

(c) In RNA, the polymer

is composed of

alternating ribose (R)

and phosphate (P)

attached to nitrogen

bases (A,U,C,G), but

it is usually a single

strand

Backbone

Backbone

RNA

N base

Pentose sugar

Phosphate

H bonds

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ATP: The Energy Molecule of Cells •Adenosine triphosphate (ATP): a nucleotide containing adenine, ribose, and three phosphates •Belongs to a category of high-energy compounds that give off energy when the bond between the second and third (outermost) phosphate is broken •This releases energy to do cellular work •Also generates adenosine diphosphate (ADP) that can be converted back to ATP

H

H

N N

N N

NH2

Adenosine

Triphosphate

(ATP)

Adenosine

Diphosphate

(ADP)

Adenosine

–O

OH OH

CH2

O –

(b)

(a)

O– O–

O O O

P P P

O O

O

O

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Fundamental Characteristics of Cells •Cells tend to be spherical, polygonal, cubical, or cylindrical •Protoplasm is encased in a cell or cytoplasmic membrane •Have chromosomes containing DNA and ribosomes for protein synthesis •Exceedingly complex in function

Fundamental Characteristics of Cells (cont’d) •Eukaryotic cells

- found in animals, plants, fungi, and protozoa

- contain organelles that perform useful functions

•Prokaryotic cells

- have no nucleus and generally no other organelles

- complex structure that engages in nearly every activity that eukaryotes can, and many can function in ways that eukaryotes cannot

Nomenclature

•The assignment of scientific names to various taxonomic categories and to individual organisms •Binomial nomenclature

- scientific name is a combination of the genus and species names

- scientific names are italicized when they are written in print and underlined when they are written by hand

- when the name is abbreviated, the genus name is abbreviated to the first initial followed by a period and the full species name is written

Classification •Organized into descending ranks, beginning with a general all-inclusive taxonomic category and ending with the smallest and most specific category •Categories

- domain

- kingdom

- phylum or division

- class

- order

- family

- genus

- species

Sample Taxonomy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

DOMAIN: Eukarya (all eukaryotic organisms)

Eukaryotic, heterotrophic

and mostly multicellular

Possess notochord, dorsal

nerve cord, pharyngeal slits

(if only in embryo)

Possess hair,

mammary glands

Digital dexterity,

large cerebral

cortex, slow

reproductive rate,

long life span

Large brain, no tail,

long upper limbs

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Primates

Family: Hominoidea

Genus: Homo Erect posture, large

cranium,

opposable thumbs

Species: sapiens Humans

Genus: Paramecium Pointed, cigar-shaped cells with

macronuclei and micronuclei

Species: caudatum Cells cylindrical,

long, and pointed

at one end

Cells rotate while

swimming and have

oral grooves

Elongated oval cells

with cilia in the oral

cavity

Single cells with

regular rows of cilia;

rapid swimmers

Only protozoa with

cilia

Includes protozoa

and algae

Kingdom: Protista

Phylum: Ciliophora

Class: Hymenostomea

Order: Hymenostomatida

Family: Parameciidae

A Universal Web of Life

•Darwin and Haeckel proposed two kingdoms: plants and animals •Haeckel later added Protista to the first two kingdoms •In the 1870s, Haeckel added the kingdom Monera

•Whittaker added the kingdom fungi during the period of 1959 – 1969, and the 5 kingdom system became the standard

- animals

- plants

- protists

- monera

- fungi

The Woese-Fox System

•Based on conserved small subunit ribosomal RNA sequences (ssu rRNA)

•Analysis of these sequences revealed a separate group for the archaeabacteria called Archaea

•An entirely new system was proposed based on domains - Bacteria

- Archaea

- Eukarya

análisis comparativo de

secuencias de DNA que

codifican para RNA

ribosomal

Procariotas