Tissue P systems with Symport/Antiport rules of one symbol are computationally complete

We consider tissue P systems using symport/ antiport rules of only one symbol where in each link (channel) between two cells at most one rule is applied, but in each channel a symport/ antiport rule has to be used if possible. We prove that any recursively enumerable set of k-dimensional vectors of natural numbers can be generated (accepted) by such a tissue P system with symport/ antiport rules of one symbol using at most 2k + 5 (at most 3k + 7) cells.