Usually, the answer is no. They don't make a big deal about the difference between arcane and divine spells, but there is one, and if you read
Adding Spells to a Wizard's Spellbook
A wizard can also add a spell to his book whenever he encounters one on a magic scroll or in another wizard's spellbook. No matter what the spell's source, the wizard must first decipher the magical writing (see Arcane Magical Writings).
And Arcane Magical Writings
To decipher an arcane magical writing (such as a single spell in another's spellbook or on a scroll), a character must make a Spellcraft check (DC 20 + the spell's level).
You will notice that it says "arcane magical writings" specifically. This means "not divine." So you can not use this procedure to put a divine spell in your spellbook. Even though the spell may be, in the abstract, on your spell list, you have in hand a divine scroll not an arcane scroll.
This should be pretty obvious from precedent from say all other versions of D&D.
Now, the Mystic Theurge is a slightly special case because the whole point of that class is to blur the lines between arcane and divine magic. However, even they do not treat divine magic as arcane or vice versa. This p-class is significatly simplified in Pathfinder and is pretty elegant, what it does is
A mystic theurge can prepare and cast spells from one of his spellcasting classes using the available slots from any of his other spellcasting classes. Spells prepared or cast in this way take up a slot one level higher than they originally occupied.
So your mystic theurge can't do anything with that divine scroll except cast it. He can prepare a bunch of Bull's Strengths using his wizard (or whatever) slots and then a bunch using his cleric (or whatever) slots. In fact, if his divine class is something weird that doesn't have Bull's Strength, he could use 3rd level slots from it to prepare arcane Bull's Strengths. Heck, he could do that anyway with the spell on his list if he felt the need to have about 20 bull's strengths in a given day (all 2nd level arcane slots, all 2nd level divine slots, all 3rd level arcane slots for divine ones, all 3rd level divine slots for arcane ones).