Blocking sweet taste receptors can help body fight off sinus infections: Researchers identify amino acids that hold the key to the process -- ScienceDaily

 Bitter taste receptors in the upper airway are a first line of defense against sinus infections, but their ability to kill harmful toxins and pathogens is blocked when the sweet taste receptors are also stimulated. While glucose and other sugars are known to trigger these sweet taste receptors, researchers at the Perelman School of Medicine of the University of Pennsylvania have now shown amino acids can also have that effect. This new understanding could help pave the way toward new treatments for chronic sinus infections. The researchers published their findings in the journal Science Signaling this week."

Here's the paper:- Bacterial d-amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells

Amyloidogenic amyloid-β-peptide variants induce microbial agglutination and exert antimicrobial activity : Scientific Reports

Amyloid-β (Aβ) peptides are the main components of the plaques found in the brains of patients with Alzheimer’s disease. However, Aβ peptides are also detectable in secretory compartments and peripheral blood contains a complex mixture of more than 40 different modified and/or N- and C-terminally truncated Aβ peptides. Recently, anti-infective properties of Aβ peptides have been reported. Here, we investigated the interaction of Aβ peptides of different lengths with various bacterial strains and the yeast Candida albicans. The amyloidogenic peptides Aβ1-42, Aβ2-42, and Aβ3p-42 but not the non-amyloidogenic peptides Aβ1-40 and Aβ2-40 bound to microbial surfaces. As observed by immunocytochemistry, scanning electron microscopy and Gram staining, treatment of several bacterial strains and Candida albicans with Aβ peptide variants ending at position 42 (Aβx-42) caused the formation of large agglutinates. These aggregates were not detected after incubation with Aβx-40. Furthermore, Aβx-42 exerted an antimicrobial activity on all tested pathogens, killing up to 80% of microorganisms within 6 h. Aβ1-40 only had a moderate antimicrobial activity against C. albicans. Agglutination of Aβ1-42 was accelerated in the presence of microorganisms. These data demonstrate that the amyloidogenic Aβx-42 variants have antimicrobial activity and may therefore act as antimicrobial peptides in the immune system.

Functional characterization of alpha-synuclein protein with antimicrobial activity.

Alpha-synuclein (α-Syn), a small (14 kDa) protein associated with Parkinson's disease, is abundant in human neural tissues. α-Syn plays an important role in maintaining a supply of synaptic vesicles in presynaptic terminals; however, the mechanism by which it performs this function are not well understood. In addition, there is a correlation between α-Syn over-expression and upregulation of an innate immune response. Given the growing body of literature surrounding antimicrobial peptides (AMPs) in the brain, and the similarities between α-Syn and a previously characterized AMP, Amyloid-β, we set out to investigate if α-Syn shares AMP-like properties. Here we demonstrate that α-Syn exhibits antibacterial activity against Escherichia coli and Staphylococcus aureus. In addition, we demonstrate a role for α-Syn in inhibiting various pathogenic fungal strains such as Aspergillus flavus, Aspergillus fumigatus and Rhizoctonia solani. We also analyzed localizations of recombinant α-Syn protein in E. coli and Candida albicans. These results suggest that in addition to α-Syn's role in neurotransmitter release, it appears to be a natural AMP.

Synthetic corkscrew peptide kills antibiotic-resistant gram-negative bacteria

An engineered peptide provides a new prototype for killing an entire category of resistant bacteria by shredding and dissolving their double-layered membranes, which are thought to protect those microbes from antibiotics.

New type of bacterial protection found within cells: Novel immune system response to infections discovered

ScienceDaily (Nov. 13, 2012) — UC Irvine biologists have discovered that fats within cells store a class of proteins ( histone proteins) with potent antibacterial activity, revealing a previously unknown type of immune system response that targets and kills bacterial infections.

MicrobeWorld - How Curry Spice Helps The Immune System Kill Bacteria

American and Danish scientists have found curcumin increases levels of a protein called (cathelicidin antimicrobial peptide or  CAMP)  that helps the immune system to fight off bacteria, viruses and fungi the first time they try to attack

Hormone plays surprise role in fighting skin infections

Antimicrobial peptides (AMPs) are molecules produced in the skin to fend off infection-causing microbes. Vitamin D has been credited with a role in their production and in the body's overall immune response, but scientists at the University of California, San Diego School of Medicine say a hormone previously associated only with maintaining calcium homeostasis and bone health is also critical, boosting AMP expression when dietary vitamin D levels are inadequate.