Transgenic Drosophila lines for LexA-dependent gene and growth regulation

Conditional expression of short hairpin RNAs with binary genetic systems is an indispensable tool for studying gene function. Addressing mechanisms underlying cell-cell communication in vivo benefits from simultaneous use of 2 independent gene expression systems. To complement the abundance of existing Gal4/UAS-based resources in Drosophila, we and others have developed LexA/LexAop-based genetic tools. Here, we describe experimental and pedagogical advances that promote the efficient conversion of Drosophila Gal4 lines to LexA lines, and the generation of LexAop-short hairpin RNA lines to suppress gene function. We developed a CRISPR/Cas9-based knock-in system to replace Gal4 coding sequences with LexA, and a LexAop-based short hairpin RNA expression vector to achieve short hairpin RNA-mediated gene silencing. We demonstrate the use of these approaches to achieve targeted genetic loss-of-function in multiple tissues. We also detail our development of secondary school curricula that enable students to create transgenic flies, thereby magnifying the production of well-characterized LexA/LexAop lines for the scientific community. The genetic tools and teaching methods presented here provide LexA/LexAop resources that complement existing resources to study intercellular communication coordinating metazoan physiology and development.

Therapy for nongonococcal urethritis: double-blind randomized comparison of two doses and two durations of minocycline

We treated 289 men who had nongonococcal urethritis with minocycline, 100 mg once or twice daily for 7 to 21 days. After 21 +/- 7 days, urethritis persisted or recurred in 31 (27%) of 114 given 7-day therapy and only nine (8%) of 110 given 21-day therapy (p = 0.0005). However, by 49 +/- 14 days, the cumulative percent rate of failure was 31% for 7-day and 30% for 21-day therapy. Thus, 21-day therapy only delayed recurrence. The higher daily dosage did not improve outcome. Urethritis persisted or recurred in 19% of men with initial Chlamydia trachomatis infection. Among men without C. trachomatis, urethritis persisted or recurred in 32% with and 52% without Ureaplasma urealyticum infection (p = 0.03). At follow-up, 79% of cases of persistent or recurrent urethritis were culture negative for C. trachomatis and U. urealyticum. The cause of C. trachomatis-negative, U. urealyticum-negative nongonococcal urethritis, which was least responsive to minocycline therapy, remains uncertain.

Bacteriology of the urethra in normal men and men with nongonococcal urethritis

Sixty-nine Caucasian males without a previous history of urethritis and who developed nongonococcal urethritis (NGU) and 39 similar men without urethritis (NU) were cultured from the urethra for Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, aerobes, and anaerobes. C. trachomatis infection was proven by culture of serology in 26 (38%) of the NGU group and 1 (3%) of the NU group; the C. trachomatis-negative NGU group had significantly more U. urealyticum (81%) than the C. trachomatis-positive NGU group (42%) or the NU group (59%). Aerobes were isolated from significantly more NU men (91%) than from men with NGU (66%). The aerobic and anaerobic flora of the two NGU groups were similar. The NU group had significantly more aerobic lactobacilli. Haemophilus vaginalis, alpha-hemolytic streptococci (not Streptococcus faecalis), and anaerobes, predominantly Bacteroides species. This study has provided information about the prevalence and the variety of the aerobic and anaerobic microbiological flora of the anterior urethra of sexually active males. It does not implicate any bacteria other than C. trachomatis and U. urealyticum as potential causes of NGU.

Differential response of chlamydial and ureaplasma-associated urethritis to sulphafurazole (sulfisoxazole) and aminocyclitols

91 men with non-gonococcal urethritis (N.G.U.) were randomly treated with either sulphafurazole (sulfisoxazole), 500 mg orally q.i.d. for 10 days, or an aminocyclitol (streptomycin or spectinomycin), 2 g intramuscularity for 1 to 3 doses at 12 h intervals. Initial urethral cultures were positive for Chlamydia trachomatis (C) in 36 (40%). Ureaplasma urealyticum (U) was isolated from the urethra or urine from20 (95%) of 21 White men in a first episode of N.G.U. who had negative chlamydia cultures. Sulphafurazole, active against C. trachomatis but not U. urealyticum in vitro, produced a clinical response in 7 of 7 men with C+U- N.G.U. and 5 of 19 with C-U+ N.G.U. (P less than 0-01). Aminocyclitols, active against U. urealyticum but relatively inactive against C. trachomatis in vitro produced a clinical response in 0 of 6 men with C+U-N.G.U., 9 of 11 men with C-U+N.G.U. from whom ureaplasma was eradicated (P less than 0-01), and 0 of 8 with C-U+ N.G.U. from whom ureaplasma was not eradicated. C+U+ N.G.U. responded poorly to both antimicrobials alone. These results support the aetiological importance of both C. trachomatis and U. urealyticum in N.G.U.