[Computational investigation of Artemisia pollen deposition in realistic nasal cavities of residents in northwest China].

Objective: To investigate the deposition rate of Artemisia pollen in different nasal cavity regions and its influence factors in residents of northwest China. Methods: Thirty healthy adults from northwest China were enrolled. The computational fluid dynamics (CFD) and discrete phase model (DPM) were used for numerical simulation of nasal structures. The pollen deposition fraction in each anatomical part was counted and the effects of pollen density and breathing rate on deposition were analyzed. SPSS 19.0 software was used for statistical analysis. Results: The hottest deposition parts of Artemisia pollen were nasal septum (30.70%±12.27%), vestibule (27.45%±8.21%), middle turbinate area (13.59%±8.98%) and nasopharynx (7.14%±5.90%). When the inspiratory flow rate increased to 30 L/min, the deposition rates of pollen in nasal vestibule and nasal septum were significantly higher than that at the rate of 15 L/min (43.20%±11.14% vs 27.45%±8.21%, 51.48%±9.77% vs 30.70%±12.27%, t value was -8.126,-5.264, respectively, all P<0.05), which indicated that with the increase of the inspiratory flow rate, the deposition hotspot moved forward. Compared with the wet Artemisia pollen, the deposition rate of the dry pollen in nasal vestibule and nasal septum decreased significantly (16.55%±4.33% vs 27.45%±8.21%, 7.09%±3.69% vs 30.70%±12.27%, t value was 8.669, 9.173, respectively, all P<0.05). The escape rate at outlet increased from 17.00%±9.57% to 43.48%±13.43% (t=-9.282, P<0.05). Conclusions: The deposition of Artemisia pollen in nasal cavity is highly concentrated. The inhalation velocity and the dry-wet degree of pollen are the main determinants of the deposition site.

Mater, a maternal effect gene required for early embryonic development in mice.

Maternal effect genes produce mRNA or proteins that accumulate in the egg during oogenesis. We show here that Mater, a mouse oocyte protein dependent on the maternal genome, is essential for embryonic development beyond the two-cell stage. Females lacking the maternal effect gene Mater are sterile. Null males are fertile.

Mater encodes a maternal protein in mice with a leucine-rich repeat domain homologous to porcine ribonuclease inhibitor.

MATER (Maternal Antigen That Embryos Require) is an ooplasm-specific protein first identified as an antigen (OP1) associated with ovarian autoimmunity in mice. Its primary structure has been deduced from full-length cDNA that encodes a 125-kDa protein required for progression of the mouse embryo beyond two cells. Expression of the gene encoding MATER is restricted to the oocyte, which makes it one of a growing, but still limited, number of maternal-effect genes in mammals. To further investigate the function of MATER during oogenesis and early development, we have characterized the gene and resultant protein. Mater is a single-copy gene in the genome of 129/Sv mice and is located at the proximal end of Chromosome (Chr) 7. The gene, spanning approximately 32 kbp, contains 15 exons ranging in size from 48 to 1576 bp, which together encode the 111 amino acid MATER protein. The first five exons encode 26-27 amino acid hydrophilic repeats and exons 8-14 encode 14 leucine-rich repeats. The three-dimensional structure of the latter domain can be closely modeled on the previously determined X-ray crystallographic coordinates of porcine ribonuclease inhibitor. These characterizations of the gene and protein provide the basis for genetic investigations of MATER function in early mammalian development.

A mouse gene encoding an oocyte antigen associated with autoimmune premature ovarian failure.

Autoimmune premature ovarian failure causes young women to develop menopausal symptoms and infertility. A similar syndrome appears in mice with postthymectomy autoimmune premature ovarian failure. We demonstrate that these mice develop antibodies against a 125-kDa protein located in the oocyte cytoplasm (ooplasm). By screening a mouse ovarian complementary DNA expression library with autoimmune serum, we have identified a novel mouse gene with a 3.75-kb ovarian transcript, the expression of which is restricted to the oocyte. The longest open reading frame (3333 bp) encodes an oocyte-specific protein, designated OP1 (ooplasm-specific protein 1). The protein is composed of 1111 amino acids with a predicted molecular mass of 125,502 Da. Based on its primary structure, it appears to be novel and has no motifs to suggest a localization other than in the cytoplasm. The ability of immune serum from mice with ovarian autoimmunity to react specifically with recombinant OP1 raises the possibility that OP1 as an antigen may play a role in murine autoimmune premature ovarian failure.

Human ZP3 restores fertility in Zp3 null mice without affecting order-specific sperm binding.

The mammalian zona pellucida surrounding ovulated eggs mediates sperm binding at fertilization, provides a postfertilization block to polyspermy, and facilitates passage of pre-implantation embryos down the oviduct. Although the three zona proteins (ZP1, ZP2, ZP3) are well conserved, mammalian fertilization is relatively specific and human sperm do not bind to the mouse zona pellucida. There are considerable in vitro data that ZP3 acts as a primary sperm adhesion molecule in mice and, by analogy, a similar role has been postulated for human ZP3. Genetically altered mice lacking ZP3 (Zp3(tm/tm)) do not form a zona pellucida and are infertile. To rescue this phenotype, transgenic mice expressing human ZP3 (67% identical to mouse ZP3) were produced and bred with Zp3(tm/tm) null mice. The resultant human ZP3 rescue females had chimeric zonae pellucidae composed of mouse ZP1, mouse ZP2 and human ZP3. Human ZP3 expressed in mouse oocytes had an apparent mass (64 kDa) indistinguishable from native human ZP3 and distinct from mouse ZP3 (83 kDa). Despite the presence of human ZP3, human sperm did not bind to the chimeric zona pellucida, and notwithstanding the absence of mouse ZP3, mouse sperm bound to ovulated eggs in vitro and fertility was restored in vivo. These data have implications regarding the molecular basis of mouse and human sperm binding to their respective zonae pellucidae.

Inhibition of zona pellucida gene expression by antisense oligonucleotides injected into mouse oocytes.

During murine oogenesis, the zona pellucida proteins (ZP1, ZP2, and ZP3) are synthesized and secreted to form an extracellular matrix that surrounds the oocyte and mediates specific biological functions essential to mammalian fertilization and early development. To investigate the relationship among the zona proteins during zona matrix assembly, we have undertaken to inhibit de novo biosynthesis of specific zona proteins with antisense oligonucleotides complementary to the 5'-ends of ZP2 (nucleotide position 19-42) and ZP3 (nucleotide 21-44) mRNAs. When injected into the cytoplasm of growing mouse oocytes, the antisense oligonucleotides targeted specific zona mRNAs for degradation, as confirmed by a RNase protection assay. Individual zona pellucida protein synthesis was followed by immunoprecipitation with ZP2- and ZP3-specific monoclonal antibodies. New zona protein synthesis from the targeted mRNA was abolished, but nontargeted zona protein continued to be synthesized. Interestingly, abolishment of either ZP2 or ZP3 protein synthesis prevented the incorporation of the other protein into the extracellular zona matrix. These results suggest that ZP2 and ZP3 proteins are independent of each other in their biosynthesis but are dependent upon each other for their incorporation into the zona pellucida matrix. This study provides an experimental system in which destruction of a targeted mRNA generates a transient loss-of-expression phenotype during mouse oocyte growth.