The G alpha i homologue gna-1 controls multiple differentiation pathways in Neurospora crassa.

Heterotrimeric G proteins are components of principal signaling pathways in eukaryotes. In higher organisms, alpha subunits of G proteins have been divided into four families, Gi, Gs, Gq, and G12. We previously identified a G alpha i homologue gna-1 in the filamentous fungus Neurospora crassa. Now we report that deletion of gna-1 leads to multiple phenotypes during the vegetative and sexual cycles in N. crassa. On solid medium, delta gna-1 strains have a slower rate of hyphal apical extension than wild type, a rate that is more pronounced under hyperosmotic conditions or in the presence of a cellophane overlay. delta gna-1 mutants accumulate less mass than wild-type strains, and their mass accumulation is not affected in the same way by exposure to light. delta gna-1 strains are defective in macroconidiation, possessing aerial hyphae that are shorter, contain abnormal swellings, and differentiate adherent macroconidia. During the sexual cycle, delta gna-1 strains are fertile as males. However, the mutants are female-sterile, producing small, aberrant female reproductive structures. After fertilization, delta gna-1 female structures do not enlarge and develop normally, and no sexual spores are produced. Thus, mutation of gna-1 results in sex-specific loss of fertility.

Cholesterol screening in childhood: does it predict adult hypercholesterolemia? The Beaver County experience.

To establish the value of screening children for hypercholesterolemia in terms of identifying future adults with hypercholesterolemia, we studied 611 individuals 9 years after they were initially screened at age 12 years. They represent 61% of a stratified sample of the original cohort, which was drawn from all seventh graders in a countywide school district. Overall, the correlation between baseline and follow-up cholesterol concentration was r = 0.52 (P less than 0.0001). Forty-nine percent of the top cholesterol quintile at baseline were similarly placed at follow-up, with 70% in the top two quintiles. Children who dropped out of the top quintile had lower body mass index at follow-up (P less than 0.05), were less frequently smokers, and tended to be more active than those who were only in the top quintile as adults.