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Pneumonia: Inflammation of any part, segment or lobe, of the lung parenchyma.

Bacterial Transformation- Concept

JoVE 10573

Background

In early 20th century, pneumonia was accountable for a large portion of infectious disease deaths1. In order to develop an effective vaccine against pneumonia, Frederick Griffith set out to study two different strains of the Streptococcus pneumoniae: a non-virulent strain with a rough appearance (R-strain) and a virulent strain with a smooth appearance…

 Lab Bio

Bacterial Transformation

JoVE 10982

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.

Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that produced pathogenic offspring. Griffith concluded that the non-pathogenic strain received something from the dead pathogenic strain that transformed it into the pathogenic strain; he called this the transforming principle. At the time of Griffith’s studies, there was heated debate surrounding the identity of the genetic material. Much early evidence implicated proteins as the hereditary molecules. Griffith’s experiments on bacterial transformation provided some of the earliest data demonstrating that DNA is the genetic material. Bacteria incorporate external DNA through transformation. Transformation occurs naturally but is also induced in laboratories—often to clone DNA. To clone a specific gene, scientists can insert the gene into a plasmid, a circular DNA molecule that can independently replicate. The plasmid often contains an antib

 Core: Biology

Respiratory Exam II: Percussion and Auscultation

JoVE 10041

Source: Suneel Dhand, MD, Attending Physician, Internal Medicine, Beth Israel Deaconess Medical Center


Learning the proper technique for percussion and auscultation of the respiratory system is vital and comes with practice on real patients. Percussion is a useful skill that is often skipped during everyday clinical practice, but if…

 Physical Examinations I

Preparing and Administering Inhaled Medications

JoVE 10390

Source: Madeline Lassche, MSNEd, RN and Katie Baraki, MSN, RN, College of Nursing, University of Utah, UT


Inhaled medications are prescribed for conditions affecting the bronchi, which branch off of the trachea, and bronchioles, which are progressively smaller conducting airways spread throughout the lung tissue. These conditions can be…

 Nursing Skills

Microscopy and Staining: Gram, Capsule, and Endospore Staining

JoVE 10513

Source: Rhiannon M. LeVeque1, Natalia Martin1, Andrew J. Van Alst1, and Victor J. DiRita1
1 Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America


Bacteria are diverse microorganisms found nearly everywhere on Earth. Many properties help distinguish them from…

 Microbiology

Respiratory Exam I: Inspection and Palpation

JoVE 10028

Source: Suneel Dhand, MD, Attending Physician, Internal Medicine, Beth Israel Deaconess Medical Center


Disorders of the respiratory system with a chief complaint of shortness of breath are among the most common reasons for both outpatient and inpatient evaluation. The most obvious visible clue to a respiratory problem will be whether the…

 Physical Examinations I

Needle Thoracostomy

JoVE 10233

Source: Rachel Liu, BAO, MBBCh, Emergency Medicine, Yale School of Medicine, New Haven, Connecticut, USA


A tension pneumothorax is a life-threatening situation in which excess air is introduced into the pleural space surrounding the lung, either through trauma to the chest cavity or as a spontaneous leak of air from the lung itself. Air…

 Emergency Medicine and Critical Care

Percussion

JoVE 10136

Source: Jaideep S. Talwalkar, MD, Internal Medicine and Pediatrics, Yale School of Medicine, New Haven, CT


Simply stated, percussion refers to the striking of one object against another to produce sound. In the early 1700s, an Austrian inn-keeper's son, named Leopold Auenbrugger, discovered that he could take inventory …

 Physical Examinations I

The TUNEL Assay

JoVE 5651

One of the hallmarks of apoptosis is the nuclear DNA fragmentation by nucleases. These enzymes are activated by caspases, the family of proteins that execute the cell death program. TUNEL assay is a method that takes advantage of this feature to detect apoptotic cells. In this assay, an enzyme called terminal deoxynucleotidyl transferase catalyzes the addition of dUTP…

 Cell Biology
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