Related Experiment Video
Updated: Jan 20, 2026
06:36
Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds
Published on: September 8, 2021
3.2K
Reducing Staphylococcus aureus resistance to lysostaphin using CRISPR-dCas9
Xia Wu1,2, Jian Zha1,2, Mattheos A G Koffas2,3
1School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, China.
Biotechnology and Bioengineering
|August 22, 2019
Summary
Staphylococcus aureus resists lysostaphin (Lst) via wall teichoic acids (WTAs) in nutrient-rich environments. Downregulating WTA synthesis genes with CRISPR-dCas9 sensitizes bacteria to Lst, enabling eradication.
Area of Science:
- Microbiology
- Biochemistry
- Genetics
Background:
- Bacteriolytic enzymes show promise against antibiotic-resistant bacteria.
- Mechanisms of bacterial resistance to peptidoglycan hydrolases are not fully understood, especially in nutrient-rich conditions found at infection sites.
Purpose of the Study:
- To investigate the resistance mechanism of Staphylococcus aureus to the bacteriolytic enzyme lysostaphin (Lst) in nutrient-rich media.
- To develop a strategy to overcome Lst resistance in Staphylococcus aureus.
Main Methods:
- Biochemical analysis to identify factors mediating Lst resistance.
- Genetic manipulation using CRISPR-dCas9 to downregulate specific genes involved in wall teichoic acid (WTA) biosynthesis.
- Assessment of Staphylococcus aureus susceptibility to Lst in different media.
Main Results:
- Staphylococcus aureus exhibits high resistance to Lst in nutrient-rich tryptic soy broth (TSB), unlike in buffered saline.
- Resistance is mediated by wall teichoic acids (WTAs) on the cell surface, which prevent Lst-cell binding.
- Inhibition or deletion of the tarO gene, crucial for WTA synthesis, significantly reduced Lst resistance.
- Downregulation of tarO, tarH, and/or tarG genes using CRISPR-dCas9 sensitized Staphylococcus aureus to Lst, leading to bacterial eradication within 24 hours in TSB.
Conclusions:
- Wall teichoic acids (WTAs) play a key role in Staphylococcus aureus resistance to lysostaphin (Lst) in metabolically active states.
- Targeting WTA biosynthesis pathways, particularly through gene downregulation, offers a potential strategy to enhance the efficacy of bacteriolytic enzymes against Gram-positive pathogens.
Related Concept Videos
01:59CRISPR
57.6K
Genome editing technologies allow scientists to modify an organism’s DNA via the addition, removal, or rearrangement of genetic material at specific genomic locations. These types of techniques could potentially be used to cure genetic disorders such as hemophilia and sickle cell anemia. One popular and widely used DNA-editing research tool that could lead to safe and effective cures for genetic disorders is the CRISPR-Cas9 system. CRISPR-Cas9 stands for Clustered Regularly Interspaced...
57.6K
02:53CRISPR and crRNAs
18.7K
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
18.7K
01:18Reducing Line Loss
370
In a three-phase circuit, line loss is an indicator of energy dissipated as heat due to the resistance of transmission lines. To address this, incorporating transformers into the system—a step-up transformer at the source and a step-down transformer at the load—is a strategic solution. Two three-phase transformers are introduced to improve this.
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
370
01:22Resistivity
4.4K
When a voltage is applied to a conductor, an electrical field is generated, and charges in the conductor feel the force due to the electrical field. The current density that results depends on the electrical field and the properties of the material. In some materials, including metals at a given temperature, the current density is approximately proportional to the electrical field. In these cases, the current density can be modeled as:
4.4K
01:19Resistance
5.7K
When a current moves through any conductor, the conductor causes some level of difficulty for the current to flow. The measure of that difficulty is known as the resistance of the material and is represented by R. Every material has its own resistance. In the case of conductors, heat is emitted whenever a current passes through them. Resistance depends on the resistivity of the material. Resistivity is a characteristic of the material used to fabricate electrical components, whereas the...
5.7K
01:22Methods of reducing fever
1.2K
The signs and symptoms of fever include hot and dry skin, flushed face, thirst, muscle aches, anorexia, headache, tachycardia, tachypnea, and fatigue. Elevated body temperature is reduced using two methods: pharmacological and nonpharmacological. Proper identification and treatment of the root cause of a fever is of utmost importance.
Pharmacological Methods of Reducing Fever:
Pharmacological Methods of Reducing Fever:
1.2K