Isolation and characterization of the gene expressing the major salivary gland protein of the female mosquito, Aedes aegypti.

We have undertaken a molecular analysis of the salivary glands of hematophagous insects in order to better understand their role in blood feeding and in the transmission of infectious diseases. To that end, genomic and cDNA clones of a gene designated D7, expressed abundantly in the adult female salivary glands of the vector mosquito aegypti, have been isolated and characterized. This gene encodes a mRNA shown by Northern analysis and in situ hybridization to tissue sections to be specifically transcribed in the distal-lateral and medial lobes of the glands, regions that are highly differentiated in females. The deduced gene product, a protein of approximately 37 kDa appears to be novel. Polyclonal antibodies made to a recombinant D7 product recognize a protein with the proper molecular weight in female salivary glands and saliva. These studies indicate that the D7 gene probably encodes the major secreted protein synthesized in the female salivary glands. The stage- and sex-limited expression of the D7 gene, and the secretion of its product, indicate that the product is most likely involved with the blood feeding capabilities of the female mosquito.

Endometrial histology after first trimester spontaneous abortion.

The endometrial histology after spontaneous abortion was investigated by performing an endometrial biopsy in the two menstrual cycles subsequent to miscarriage in 12 women. In the first cycle, 66% (8/12) of the biopsies had the following abnormalities: (1) proliferative endometrium (n = 4), (2) proliferative glands and decidualized stroma (n = 1), (3) endometritis (n = 1), and (4) luteal insufficiency (n = 2). In the second cycle, 20% (2/10) of the biopsies demonstrated luteal insufficiency. Forty-five percent (10/22) of the first two cycles after spontaneous abortion demonstrated abnormal endometrial histology, with the first appearing more abnormal than the second (P = 0.06). Two conceptions occurred during the study period; both were uneventful term pregnancies. These findings suggest that a large proportion of the first two menstrual cycles after spontaneous abortion and curettage are abnormal, with the first cycle being more frequently abnormal than the second.

A randomized, controlled trial of clomiphene citrate and intrauterine insemination in couples with unexplained infertility or surgically corrected endometriosis.

This study was initiated to test the hypothesis that treatment with clomiphene citrate (CC) and intrauterine insemination (IUI) results in increased fecundity when compared with periovulatory intercourse in couples with either unexplained infertility or surgically corrected endometriosis. Sixty-seven couples entered a randomized, prospective trial comparing CC/IUI with observation. During the study, there were 14 pregnancies in 148 treated cycles (fecundity = 0.095) compared with 5 pregnancies in 150 untreated cycles (fecundity = 0.033). Using life-table analysis and the log-rank test, the difference in fecundities was statistically significant. Pregnancy outcome was not significantly different between the two groups. When comparing conception with nonconception cycles during treatment, no differences between the size of the lead follicle or the number of dominant follicles was detected. We conclude that treatment with CC/IUI improves fecundity in couples with unexplained infertility or surgically corrected endometriosis.

A salivary gland-specific, maltase-like gene of the vector mosquito, Aedes aegypti.

Genomic and cDNA clones of a gene expressed specifically in the salivary glands of adult Aedes aegypti have been isolated and sequenced. This gene encodes an abundant mRNA that is transcribed throughout the male salivary gland but only in the cells of the proximal lateral lobes of the female gland. The deduced protein has many basic amino acids, several possible sites for N-glycosylation, and displays striking similarities with the products of a yeast maltase gene and three previously unidentified genes from Drosophila melanogaster. We propose the name 'Maltase-like I' (MalI) to designate this gene. The presumed function of this gene product is to assist the mosquito in its sugar-feeding capabilities. The mosquito and fruitfly genes have similar structural features 5' to the protein coding regions, indicating that these genes may share common control mechanisms.

Regulation of acetylcholine receptor transcript expression during development in Xenopus laevis.

The level of transcripts encoding the skeletal muscle acetylcholine receptor (AChR) was determined during embryonic development in Xenopus laevis. cDNAs encoding the alpha, gamma, and delta subunits of the Xenopus AChR were isolated from Xenopus embryo cDNA libraries using Torpedo AChR cDNAs as probes. The Xenopus AChR cDNAs have greater than 60% amino acid sequence homology to their Torpedo homologues and hybridize to transcripts that are restricted to the somites of developing embryos. Northern blot analysis demonstrates that a 2.3-kb transcript hybridizes to the alpha subunit cDNA, a 2.4-kb transcript hybridizes to the gamma subunit cDNA, and that two transcripts, of 1.9 and 2.5 kb, hybridize to the delta subunit cDNA. RNase protection assays demonstrate that transcripts encoding alpha, gamma, and delta subunits are coordinately expressed at late gastrula and that the amount of each transcript increases in parallel with muscle-specific actin mRNA during the ensuing 12 h. After the onset of muscle activity the level of actin mRNA per somite remains relatively constant, whereas the level of alpha subunit and delta subunit transcripts decrease fourfold per somite and the level of gamma subunit transcript decreases greater than 50-fold per somite. The decrease in amount of AChR transcripts per somite, however, occurs when embryos are paralyzed with local anaesthetic during their development. These results demonstrate that AChR transcripts in Xenopus are initially expressed coordinately, but that gamma subunit transcript levels are regulated differently than alpha and delta at later stages. Moreover, these results demonstrate that AChR transcript levels in Xenopus myotomal muscle cells are not responsive to electrical activity and suggest that AChR transcript levels are influenced by other regulatory controls.