Do I need a comma before "no specific" in:
In the tissue samples of the primate brain cortex, liver, muscle, kidney, lymphatic node, spleen and tonsil no specific immunohistochemical staining by Z011 was observed.
I found this explanation:
If a prepositional phrases contains four or fewer words, usually no comma is needed as in the following sentence: On the table a bottle of champagne rested, conserving its energy for the upcoming festivities. Prepositional phrases of five or more words require a comma: Beneath the dusty redwood table, the cat crouched with murderous anticipation. The punctuation marks serve to indicate how the sentence is to be read aloud. As such, the first sentence would have no pause, whereas the second sentence would be read with a slight pause after table. While the word count may appear arbitrary, it reflects an organic speech pattern.
The prepositional phrase in my example has more than four words, but they are themselves set off by commas. Maybe there's no need then for a comma before "no specific"?