The increasing use of nanomaterials has raised concerns about their potential risks to human health. Recent studies have shown that nanoparticles can cross the placenta barrier in pregnant mice and cause neurotoxicity in their offspring, but a more detailed understanding of the effects of nanoparticles on pregnant animals remains elusive. Here, we show that silica and titanium dioxide nanoparticles with diameters of 70 nm and 35 nm, respectively, can cause pregnancy complications when injected intravenously into pregnant mice. The silica and titanium dioxide nanoparticles were found in the placenta, fetal liver and fetal brain. Mice treated with these nanoparticles had smaller uteri and smaller fetuses than untreated controls. Fullerene molecules and larger (300 and 1,000 nm) silica particles did not induce these complications. These detrimental effects are linked to structural and functional abnormalities in the placenta on the maternal side, and are abolished when the surfaces of the silica nanoparticles are modified with carboxyl and amine groups.

Roberts syndrome is an autosomal recessive disorder characterized by craniofacial anomalies, tetraphocomelia and loss of cohesion at heterochromatic regions of centromeres and the Y chromosome. We identified mutations in a new human gene, ESCO2, associated with Roberts syndrome in 15 kindreds. The ESCO2 protein product is a member of a conserved protein family that is required for the establishment of sister chromatid cohesion during S phase and has putative acetyltransferase activity.

The cDNA for a murine galactocerebrosidase was isolated from a murine testis cDNA library on the basis of its homology with the cDNA for human galactocerebrosidase and a PCR method was used to clone the 5′ end. It has a 2,278‐nucleotide sequence including a 2,004‐nucleotide open reading frame, which encodes 668 amino acid residues. The identity between the human and murine amino acid sequences was very high, being calculated to be 84%. Sequencing of cDNA from liver of the twitcher mouse revealed a nonsense mutation at codon 339 (TGG → TGA). The most abundant mRNA of the murine galactocerebrosidase gave a 3.6‐kb band, which was not detected in twitcher mice. This suggests that the cDNA (2,278 bp) we characterized represents a minor species generated by an alternate poly(A) signal and that most of the mRNA has a much longer 3′‐untranslated region. Genome analysis revealed that this mutation was homozygous in the twitcher and heterozygous in the carrier but was not present in normal mice. The normal mouse cDNA but not the mutant cDNA of the galactocerebrosidase transfected into COS1 cells gave rise to an increase in enzymatic activity. We concluded that this mutation results in the deficiency of galactocerebrosidase in the twitcher mouse.

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Ureaplasma spp. is detected in the urogenital tract, including the vagina, cervix, chorioamnion, and placenta. Their colonization is associated with histologic chorioamnionitis (CAM), often observed in placentas from preterm delivery. We isolated Ureaplasma spp. from 63 preterm placentas among 151 specimens, which were delivered at Ͻ32 wk of gestation. Of the 63 placentas, 52 (83%) revealed CAM in cultures positive for Ureaplasma spp., however, CAM was observed only in 30% (26/88) of cultures negative for Ureaplasma spp. (p Ͻ 0.01). Colonization by Ureaplasma spp. was an independent risk factor for CAM (OR, 11.27; 95% CI,). Characteristic neutrophil infiltration was observed in the amnion and subchorion (bistratified pattern) in cultures positive for Ureaplasma spp. FISH analysis of CAM placenta with male infant pregnancy indicated that bistratified infiltrated neutrophils showed the XX karyotype and umbilical vein infiltrated neutrophils showed XY karyotype. The distribution of sulfoglycolipid, the receptor of Ureaplasma spp., was mainly detected in the amnion. Ureaplasmal urease D protein and ureB gene were both detected in the amnion, indicating direct colonization by Ureaplasma spp. U reaplasma spp. is the smallest self-replicating organism, both in genome size and in cellular dimensions. It lacks cell walls and exists in association with eukaryotic cells, mainly colonizing mucosal surfaces of the respiratory and urogenital tracts (1). Ureaplasma spp. is a common inhabitant of the lower genital tract and isolated from 40 to 80% women of child-bearing age (2). However, once Ureaplasma spp. spreads from the lower genital tract into the body, this microorganism exerts widespread pathogenic effects, such as chorioamnionitis (CAM), urinary tract infections, preterm labor, and spontaneous abortion. On the other hand, Ureaplasma spp. infection is also reported as a risk factor for lethal pneumonia, chronic lung disease, and meningitis of fetuses and neonates (3).CAM is a placental finding associated with premature rupture of membranes (PROM) and preterm birth, which are the most important causes of perinatal morbidity and mortality (4,5). Previous studies showed that CAM was positively related to the isolation of Ureaplasma spp (6,7). Although many researchers reported the detection of Ureaplasma spp. from specimens of vagina, cervix, chorioamnion, and placenta using culture or PCR methods (8 -12), the precise pathologic findings of CAM with Ureaplasma spp. remain unclear.A variety of infectious microorganisms use specific host cell surface molecules as receptors. Such receptors provide a mechanism for intimate interaction with the host cell membrane and in some cases may facilitate the subsequent entry of the organism into the cell (13). Ureaplasma spp. and Mycoplasma hominis were shown to specifically recognize host cell surface glycolipids (sulfogalactoglycerolipid and the sphingolipid counterpart, sulfogalactosyl ceramide), which have been implicated in spermegg interactions (14). This glycolipid rec...

Thermostable direct hemolysin (TDH) is a major virulence factor of Vibrio parahaemolyticus that causes pandemic foodborne enterocolitis mediated by seafood. TDH exists as a tetramer in solution, and it possesses extreme hemolytic activity. Here, we present the crystal structure of the TDH tetramer at 1.5 Å resolution. The TDH tetramerformsacentralporewithdimensionsof23Å indiameterand ϳ50 Å in depth. -Cation interactions between protomers comprising the tetramer were indispensable for hemolytic activity of TDH. The N-terminal region was intrinsically disordered outside of the pore. Molecular dynamic simulations suggested that water molecules permeate freely through the central and side channel pores. Electron micrographs showed that tetrameric TDH attached to liposomes, and some of the tetramer associated with liposome via one protomer. These findings imply a novel membrane attachment mechanism by a soluble tetrameric pore-forming toxin.Vibrio parahaemolyticus is a Gram-negative marine bacterium known to be one of the major causes of pandemic seafoodborne gastroenteritis. V. parahaemolyticus possesses two circular replicons of 3.2 and 1.9 megabase pairs, which might confer an advantage by enabling DNA replication in seawater of lower temperature and/or low nutritional value (1, 2). Such an advantage would potentially increase risks of food intoxication by allowing explosive expansion of the population of the microorganism. Hemolysis on Wagatsuma agar (a blood agar), known as the Kanagawa phenomenon, is associated with human pathogenic strains of V. parahaemolyticus. A major virulence factor of this pathogen is the thermostable direct hemolysin (TDH) 7 (3-5), which has a variety of biological activities including hemolytic activity, cardiotoxicity, and enterotoxicity. There are two copies of the tdh gene (or its homologue trh) in pathogenic V. parahaemolyticus, indicating the importance of this exotoxin for survival of the organism (2). The mature form of TDH consists of 165 amino acids, including a single intramolecular disulfide bond, but no close homologue of TDH has been found in other organisms. The significance of Arg 46 , Gly 62 , Trp 65 , and Gly 90 residues on hemolysis was determined by site-directed mutagenesis (3, 6).The common features of the bacterial pore-forming toxin are as follows. 1) It is released as a soluble monomer into the extra-bacterial space. 2) It oligomerizes to form a pore at the host cell membrane (7,8). An earlier study reported that TDH acted as a pore-forming toxin, creating a functional pore ϳ20 Å in diameter (reviewed in Ref. 3). We previously constructed a low resolution C 4 symmetric model of tetrameric TDH in solution based on small angle x-ray scattering (SAXS), transmission electron microscopy (TEM), and analytical ultracentrifugation (9). However, the precise structure and the mechanism for its pore-forming toxicity are still unknown. Several bacterial toxins, including TDH, show paradoxical responses to heat treatment, known as the Arrhenius effect (10, * This study was s...

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