Extragenic suppressors of the nimX2(cdc2) mutation of Aspergillus nidulans affect nuclear division, septation and conidiation.

The Aspergillus nidulans NIMX(CDC2) protein kinase has been shown to be required for both the G(2)/M and G(1)/S transitions, and recent evidence has implicated a role for NIMX(CDC2) in septation and conidiation. While much is understood of its G(2)/M function, little is known about the functions of NIMX(CDC2) during G(1)/S, septation, and conidiophore development. In an attempt to better understand how NIMX(CDC2) is involved in these processes, we have isolated four extragenic suppressors of the A. nidulans nimX2(cdc2) temperature-sensitive mutation. Mutation of these suppressor genes, designated snxA-snxD for suppressor of nimX, affects nuclear division, septation, and conidiation. The cold-sensitive snxA1 mutation leads to arrest of nuclear division during G(1) or early S. snxB1 causes hyperseptation in the hyphae and sensitivity to hydroxyurea, while snxC1 causes septation in the conidiophore stalk and aberrant conidiophore structure. snxD1 leads to slight septation defects and hydroxyurea sensitivity. The additional phenotypes that result from the suppressor mutations provide genetic evidence that NIMX(CDC2) affects septation and conidiation in addition to nuclear division, and cloning and biochemical analysis of these will allow a better understanding of the role of NIMX(CDC2) in these processes.

Mumps outbreak in a highly vaccinated population.

From October 1988 to April 1989, a large mumps outbreak occurred in Douglas County, Kansas. Of the 269 cases, 208 (77.3%) occurred among primary and secondary school students, of whom 203 (97.6%) had documentation of mumps vaccination. Attack rates were highest for students attending junior high school (8.0%), followed by high school (2.0%) and elementary school (0.7%). A retrospective cohort study conducted at one junior high school with an attack rate of 12.9% did not find age at vaccination or type of vaccine received (single or combined antigen) to be risk factors for vaccine failure. Students vaccinated more than 4 years before the outbreak appeared to have a higher attack rate than those vaccinated more recently (relative risk (RR) = 4.3; 95% confidence interval (CI) = 0.6, 30.0); however, this association did not exist when risk was evaluated based on number of vaccine doses received. Students who had documentation of receiving only one dose of vaccine were at greater risk than those who had received two doses (RR = 5.2; 95% CI = 1.0, 206.2). Overall, vaccine effectiveness among Douglas County junior high school students was estimated to be 83% (95% CI = 57%, 94%). These data suggest that mumps vaccine failure and the failure to vaccinate have contributed to the relative resurgence of mumps observed in the United States since 1986. The recent change in immunization policy to recommend a two-dose schedule of measles-mumps-rubella vaccine should help reduce the occurrence of mumps outbreaks in highly vaccinated populations.