Update pycsar.md according to Hackaton guidelines, see...

Update pycsar.md according to Hackaton guidelines, see #227.

content/3.defense-systems/pycsar.md

@@ -10,9 +10,23 @@ tableColumns:
     Activator: Signaling molecules
     Effector: Membrane disrupting, Nucleotides modifying
     PFAM: PF00004, PF00027, PF00211, PF00899, PF01734, PF10137, PF14461, PF14464, PF18145, PF18153, PF18303, PF18967
+contributors: 
+  - Lucas Paoli
+relevantAbstracts:
+  - doi: 10.1016/j.cell.2021.09.031
+  - doi: 10.1038/s41586-022-04716-y
 ---
 
 # Pycsar
+
+## Description
+
+The pyrimidine cyclase system for antiphage resistance (Pycsar) :ref{doi=10.1016/j.cell.2021.09.031}. In turn, phages encode anti-Pycsar (Apic) proteins encoded that counteract Pycsar defenses :ref{doi=10.1038/s41586-022-04716-y}
+
+## Molecular mechanisms
+
+Pycsar uses cyclic nucleotide (pyrimidine cyclase) signals to induce cell death via Abi effectors activation and prevent viral propagation, while Apic degrade cyclic nucleotide signals to prevent host immune responses :ref{doi=10.1016/j.cell.2021.09.031,10.1038/s41586-022-04716-y}. 
+
 ## Example of genomic structure
 
 The Pycsar system is composed of 2 proteins: AG_cyclase and, Effector_TIR.
@@ -101,13 +115,3 @@ end
     style Title3 fill:none,stroke:none,stroke-width:none
     style Title4 fill:none,stroke:none,stroke-width:none
 </mermaid>
-## Relevant abstracts
-
-::relevant-abstracts
----
-items:
-    - doi: 10.1016/j.cell.2021.09.031
-
----
-::
-