https://padlet.com/nhusspil98/faeyqgkv71u6 Physical Microbe en-us 2018-09-20 00:32:44 UTC 2025-11-26 18:45:45 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Carfront.png nhusspil98 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283687288 Fast facts on antibiotics

• Alexander Fleming discovered penicillin, the first natural antibiotic, in 1928.
• Antibiotics cannot fight viral infections.
• Fleming predicted the rise of antibiotic resistance.
• Antibiotics either kill or slow the growth of bacteria.
• Side effects can include diarrhea, an upset stomach, and nausea.

]]> 2018-09-20 00:36:18 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283687288 nhusspil98 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283688189 The mechanisms incl. The production of reactive oxygen species , cation release, biomolecule damages, ATP depletion and membrana interaction]]> 2018-09-20 00:42:23 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283688189 aishah2196 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689128 - It can penetrate both Gram-positive and Gram-negative bacteria, but it is more active towards Gram-negative bacteria
- It could also interact with the DNA and proteins inside the cell by disrupting DNA replication, protein denaturation, and enzyme activity of the cell]]> 2018-09-20 00:49:02 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689128 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689346 Methicillin
-inhibit cross-linkage between the linear pepridoglycan chain.
-competitively inhibit transpeptidase enzyme binding protein which is main component of peptidoglycan cell wall.

Beta-lactam 
-bind to penicillin binding protein (catalyze cross-linking bacterial wall]]> 2018-09-20 00:50:46 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689346 aqilah_raliza https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689418 - AgNP is an antimicrobial agents
- Useful in wound management which is in healing process as well as the modulation of cytokines results in tissue repair
- Treat ulcers since 18th century
- AgNP disrupt the outer membrane of the target cell
- Synergistic effect that occurs when combined with other natural and synthetic compound (AgNP and penazine-1-carboxamide increases the antibacterial effect against MRSA strains by 32-fold which results in morphological alterations of bacteria cell wall)
- Wong and Liu proposed two possible mechanism of silver nanoparticles
- One is AgNP provide large surface area for contact with bacteria allowing particles to attach to cell and easily penetrate into bacteria
- Another one is AgNP interfere with the respiratory chain in bacteria mitochondria causing cell death
- AgNP toxic to bacteria but not to human]]> 2018-09-20 00:51:25 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283689418 nhusspil98 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283690237 ⏩very small so can enter biological tissues
⏩ can mixed into other material to form composite materials 
⏩ Nanoparticulates materials are used is some paints, cosmetics and sunscreens, nano particles of silver are added to a special type of sock
⏩ Silver nanoparticles kill bacteria that lead to smelly feet
⏩ have high surface area to volume ratio and can be excellent catalyst]]> 2018-09-20 00:57:16 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283690237 aqilah_raliza https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283691523 2018-09-20 01:05:58 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283691523 aqilah_raliza https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283691746 ...]]> 2018-09-20 01:07:36 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283691746 aqilah_raliza https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283692221 The formation of silver nanoparticles can be observed by a change in color since small nanoparticles of silver are yellow. A layer of absorbed borohydride anions on the surface of the nanoparticles keep the nanoparticles separated. When sodium cholride (NaCl) is added the nanoparticles aggregate and the suspension turns cloudy gray. The addition of a small amount of polyvinyl pyrrolidone will prevent aggregation.]]> 2018-09-20 01:10:54 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283692221 aqilah_raliza https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283693250 Antibiotics are medicines used to prevent and treat bacterial infections. Antimicrobial resistance is a broader term, encompassing resistance to drugs to treat infections caused by other microbes as well, such as parasites (e.g. malaria), viruses (e.g. HIV) and fungi (e.g. Candida). The terms antimicrobial and antibiotic encompass a wide variety of pharmaceutical agents that include antibacterial, antifungal, antiviral, and antiparasitic drugs. But what is the difference between antibiotic and antimicrobial substances? All antibiotics are antimicrobials, but not all antimicrobials are antibiotics. In contrast, the term “antimicrobials” include all agents that act against all types of microorganisms – bacteria (antibacterial), viruses (antiviral), fungi (antifungal) and protozoa (antiprotozoal). ]]> 2018-09-20 01:17:19 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283693250 kohilavaaniganesan https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283816651 2018-09-20 10:38:05 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283816651 kohilavaaniganesan https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283820886 • Gram-positive bacteria are more resistant to NP mechanisms of action. It is hypothesized that the differing cell walls are the reason this phenomenon exists. 

Gram-negative bacteria cells are covered by a layer of lipopolysaccharides (1–3 µm thick) and peptidoglycans (~ 8 nm thick). This arrangement may facilitate the entrance of released ions from NPs into the cell. 

- On the other hand, Gram-positive bacteria possess a peptidoglycan layer much thicker than Gram-negative bacteria, spanning over 80 nm with covalently attached teichoic and teichuronic acids.

- The cell wall destruction that occurs from physical interaction between NPs and the cell wall is more detrimental for Gram-negative bacteria as they lack the thick peptidoglycan layer found in Gram-positive bacteria that could possibly act as a protective layer.

- Another potential reason for Gram-negative susceptibility to NPs is that Gram-negative bacteria are coated with lipopolysaccharide molecules, which carry a negative charge. These negatively charged molecules have a higher affinity for the positive ions that most of the NPs release, leading to a buildup and increased uptake of ions, which then cause intracellular damage.

- Both Gram-positive and -negative bacteria have a negatively charged cell wall, a characteristic that is hypothesized to influence the interactions between the cell walls of the bacteria and NPs or ions released from them.]]> 2018-09-20 10:49:51 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/283820886 aishah2196 https://padlet.com/nhusspil98/faeyqgkv71u6/wish/286286797 2018-09-26 22:48:45 UTC https://padlet.com/nhusspil98/faeyqgkv71u6/wish/286286797