Nucleotides as Bacterial Second Messengers.

In addition to comprising monomers of nucleic acids, nucleotides have signaling functions and act as second messengers in both prokaryotic and eukaryotic cells. The most common example is cyclic AMP (cAMP). Nucleotide signaling is a focus of great interest in bacteria. Cyclic di-AMP (c-di-AMP), cAMP, and cyclic di-GMP (c-di-GMP) participate in biological events such as bacterial growth, biofilm formation, sporulation, cell differentiation, motility, and virulence. Moreover, the cyclic-di-nucleotides (c-di-nucleotides) produced in pathogenic intracellular bacteria can affect eukaryotic host cells to allow for infection. On the other hand, non-cyclic nucleotide molecules pppGpp and ppGpp are alarmones involved in regulating the bacterial response to nutritional stress; they are also considered second messengers. These second messengers can potentially be used as therapeutic agents because of their immunological functions on eukaryotic cells. In this review, the role of c-di-nucleotides and cAMP as second messengers in different bacterial processes is addressed.

16S rRNA gene-based identification of bacteria in postoperative endophthalmitis by PCR- Denaturing Gradient Gel Electrophoresis (PCR-DGGE) fingerprinting

Conventional microbiological culture techniques are frequently insufficient to confirm endophthalmitis clinical cases which could require urgent medical attention because it could lead to permanent vision loss. We are proposing PCR-DGGE and 16S rRNA gene libraries as an alternative to improve the detection and identification rate of bacterial species from endophthalmitis cases.

Peptidoglycan from Staphylococcus aureus induces the overexpression of TRLs 1-8 mRNA in corneal fibroblasts, but its lipoteichoic acid and muramyl dipeptide only induced the overexpression of TLR5 or TRL9

Lipopolysaccharide induces TLR-1-8 mRNAs over-expression in corneal fibroblast. Analyzing if other TLR-ligands can do the same, we found that peptidoglycan does, but not muramyldipeptide, lipoteichoic acid and polyI:C. This suggests that the recognition of lipopolysaccharide and peptidoglycan is enough to alert these cells against microorganisms through the over-expression of the majority TLRs.