  We present results on the quark unpolarized, helicity and transversity parton
distributions functions of the nucleon. We use the quasi-parton distribution
approach within the lattice QCD framework and perform the computation using an
ensemble of twisted mass fermions with the strange and charm quark masses tuned
to approximately their physical values and light quark masses giving pion mass
of 260 MeV. We use hierarchical probing to evaluate the disconnected quark
loops. We discuss identification of ground state dominance, the Fourier
transform procedure and convergence with the momentum boost. We find non-zero
results for the disconnected isoscalar and strange quark distributions. The
determination of the quark parton distribution and in particular the strange
quark contributions that are poorly known provide valuable input to the
structure of the nucleon.
