Bacteria are divided into two types, gram-positive and gram-negative, with the primary difference being the nature of the bacterial cell wall. Little is known about how gram-positive bacteria—such as those that can lead to food poisoning, skin disorders and toxic shock—avoid being killed by AMPs. AMPs are made by virtually all groups of organisms, including amphibians, insects, several invertebrates and mammals, including humans.
“Gram-positive bacteria are major threats to human health, especially due to increasing problems with drug resistance, and these findings may help chart a path to designing new drugs to bolster our antimicrobial treatment options,” notes NIAID Director Anthony S. Fauci, M.D.
Led by Michael Otto, Ph.D., of NIAID’s Rocky Mountain Laboratories (RML), the scientists used the gram-positive bacterium Staphylococcus epidermidis to study its response to a specific human AMP, human beta defensin 3. S. epidermidis is one of several hard-to-treat infectious agents that can be transmitted to patients in hospitals via contaminated medical implants. Findings by Dr. Otto’s research group are published in the May 29 issue of the Proceedings of the National Academy of Science. Other well-known types of gram-positive bacteria include agents that cause anthrax, strep throat, flesh-eating disease and various types of food poisoning.
In gram-negative bacteria—such as those that cause plague and salmonellosis—a sensory and gene regulation system named PhoP/PhoQ protects invading bacteria, and scientists believe if they develop a better understanding of this system they could develop new drugs that are more effective at protecting people from infection.
Likewise, now Dr. Otto and his research group are hoping for similar possibilities for gram-positive bacteria with their discovery of “aps,” which stands for antimicrobial peptide sensor. Aps has three parts: apsS, the sensor region; apsR, the gene regulation region; and apsX, which has an unknown function that Dr. Otto’s group is investigating. Studies show that all three components of aps must be present for the system to function and effectively protect bacteria from AMPs.
“We are aware that for gram-negative bacteria, PhoP/PhoQ has been called a premier target for antimicrobial drug discovery, but little corresponding work has been done with gram-positive bacteria,” Dr. Otto says. “Our group is excited by what we have demonstrated—an efficient and unique way that gram-positive bacteria control resistance—and we are continuing our investigation of the aps sensing system being used for drug development.”
Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy