  We evaluate the strangeness-conserving $N N$, $\Sigma\Sigma$, $\Xi\Xi$,
$\Lambda\Sigma$ and the strangeness-changing $\Lambda N$, $\Sigma N$,
$\Lambda\Xi$, $\Sigma\Xi$ axial charges in lattice QCD with two flavors of
dynamical quarks and extend our previous work on
pseudoscalar-meson-octet-baryon coupling constants so as to include
$\pi\Xi\Xi$, $K\Lambda\Xi$ and $K\Sigma\Xi$ coupling constants. We find that
the axial charges have rather weak quark-mass dependence and the breaking in
SU(3)-flavor symmetry is small at each quark-mass point we consider.
