Discordant twin: marked vascular communication between separated dichorionic diamniotic placentas.

We report on a woman who gave birth to dichorionic diamniotic twins with a birthweight discordancy of 30%. Her placenta exhibited characteristic features. The placental villous tissues were completely separated, but there was marked vascular communication between the two placentas. The lighter twin received less blood than the heavier twin via these vascular communications. Although the details are unknown, this abnormal placental structure may have caused the weight discordancy in this case. Clinicians must pay attention to placental vascular communication as one possible cause of twin discordancy in not only monochorionic but also dichorionic twins.     

Strange kinetic phase in the extremely early folding process of beta-lactoglobulin

A continuous-wave probed laser-induced temperature jump system was constructed and applied to monitor the changes in tryptophan fluorescence of the beta-lactoglobulin during its folding; the kinetic phases were traced from 300 ns to 10 ms after a temperature jump. Notably, an early phase with typical squeezed-exponential characteristics, [exp[-(kt)(beta)], beta>1.0], was observed around several tens of microseconds after the temperature jump, which is actually the earliest phase ever observed for beta-lactoglobulin. This process can be explained by conformational shift occurring within the unfolded ensemble (U-->U'), which is followed by the non-native intermediate (I) formation of this protein.     

Modeling of a propagation mechanism of infectious prion protein; a hexamer as the minimum infectious unit

To construct a new model of the propagation mechanism of infectious scrapie-type prion protein (PrP(Sc)), here we conducted a disruption simulation of a PrP(Sc) nonamer using structure-based molecular dynamics simulation method based on a hypothetical PrP(Sc) model structure. The simulation results showed that the nonamer disrupted in cooperative manners into monomers via two significant intermediate states: (1) a nonamer with a partially unfolded surface trimer and (2) a hexamer and three monomers. Dimers and trimers were rarely observed. Then, we propose a new PrP(Sc) propagation mechanism where a hexamer plays an essential role as a minimum infectious unit.     

Drosophila Dalmatian combines sororin and shugoshin roles in establishment and protection of cohesion

Sister chromatid cohesion is crucial to ensure chromosome bi‐orientation and equal chromosome segregation. Cohesin removal via mitotic kinases and Wapl has to be prevented in pericentromeric regions in order to protect cohesion until metaphase, but the mechanisms of mitotic cohesion protection remain elusive in Drosophila. Here, we show that dalmatian (Dmt), an ortholog of the vertebrate cohesin‐associated protein sororin, is required for protection of mitotic cohesion in flies. Dmt is essential for cohesion establishment during interphase and is enriched on pericentromeric heterochromatin. Dmt is recruited through direct association with heterochromatin protein‐1 (HP1), and this interaction is required for cohesion. During mitosis, Dmt interdependently recruits protein phosphatase 2A (PP2A) to pericentromeric regions, and PP2A binding is required for Dmt to protect cohesion. Intriguingly, Dmt is sufficient to protect cohesion upon heterologous expression in human cells. Our findings of a hybrid system, in which Dmt exerts both sororin‐like establishment functions and shugoshin‐like heterochromatin‐based protection roles, provide clues to the evolutionary modulation of eukaryotic cohesion regulation systems.     

PNA monomers fully compatible with standard Fmoc-based solid-phase synthesis of pseudocomplementary PNA

Here we report the synthesis of new PNA monomers for pseudocomplementary PNA (pcPNA) that are fully compatible with standard Fmoc chemistry. The thiocarbonyl group of the 2-thiouracil (sU) monomer was protected with the 4-methoxy-2-methybenzyl group (MMPM), while the exocyclic amino groups of diaminopurine (D) were protected with Boc groups. The newly synthesized monomers were incorporated into a 10-mer PNA oligomer using standard Fmoc chemistry for solid-phase synthesis. Oligomerization proceeded smoothly and the HPLC and MALDI-TOF MS analyses indicated that there was no remaining MMPM on the sU nucleobase. The new PNA monomers reported here would facilitate a wide range of applications, such as antigene PNAs and DNA nanotechnologies.     

Circular dichroic and fluorometric studies on the acid-induced isomerization of bovine plasma albumin--1 -anilino-8-naphthalenesulfonate complex

The acid-induced isomerization (the N-F transition) and expansion of bovine plasma albumin--1-anilino-8-naphthalenesulfonate complex, BPA-ANS1.0 complex (molar ratio of added ANS to BPA = 1.0) were studied by measuring fluorescence and induced CD spectra of ANS. Decrease in the reciprocal of fluorescence polarization, increase in fluorescence intensity and blue shift of fluorescence of ANS in BPA-ANS1.0 complex were correlated with the initial part of the N-F transition and/or the N-F1 transition. Induced CD spectra of ANS showed positive bands at 250-258 and 320-350 nm and one negative band at 280 nm. Most of changes (decreases) in -[theta]280 were also correlated with the initial part of the N-F transition and/or the N-F1 transition. Changes in fluorescence parameters and induced CD spectra of ANS (-[theta]280) might indicate the conformational changes around a strong ANS binding site in the N-terminal domain (Reed et al. (1975), Jonas & Weber (1970) and Brown & Shockley (1982].     

High-performance liquid chromatographic analysis of a new β-lactam antibiotic, 6059-s (moxalactam)

Reversed-phase high-performance liquid chromatography was applied to the quantitative determination of a new β-lactam antibiotic, 6059-S, and its R- and S-epimers were resolved. The procedure was also applied to pharmaceuticals and human urine samples. Chromatographic separation was effected on a bonded hydrophobic stationary phase with two mobile phases: methanol-phosphate buffer for the resolution of the epimers and methanol-tetra-n-butylammonium phosphate for the quantitation of 6059-S. For the determination of 6059-S in human urine, the latter mobile phase was used successfully without interference by the other urine components. An in vivo experiment was conducted by administering intravenously 1 g of 6059-S to seven volunteers and analysing their urine by chromatographic and microbiological assays, and a comparison of the results gave a correlation coefficient of 0.9954. One-compartment model analysis of the time-course data revealed that 6059-S was excreted in urine intact with a rate constant of 0.433 h^-1.     

Detection and isolation of tick‐borne bacteria (Anaplasma spp., Rickettsia spp., and Borrelia spp.) in Amblyomma varanense ticks on lizard (Varanus salvator)

Ticks are one of the arthropods that play an important role in the transmission of numerous pathogens to livestock and humans. We investigated the presence of tick‐borne bacteria in 23 Amblyomma varanense that fed on a water monitor (Varanus salvator) in Indonesia. Anaplasmataceae and borreliae were detected by PCR in 17.4% and 95.7% of ticks, respectively. “Candidatus Rickettsia sepangensis”, spotted fever group of Rickettsia, was detected in 21.7% of ticks. The water monitor is a common reptile that is widely encountered in city areas in Asian countries. Our results suggested that Am. varanense on water monitor in Indonesia harbored several kinds of bacteria.     

Enhancement of interferon-induced 2–5 oligoadenylate synthetase activity by retinoic acid in human histiocytic lymphoma U937 cells and WISH cells

The effect of retinoic acid (RA) on the level of interferon (IFN)-induced 2-5 oligoadenylate (2-5A) synthetase activity was examined in human histiocytic lymphoma U937 cells and WISH cells** in order to ascertain the role of this polymerase in interaction between IFNs and RA. Cultures containing both IFNs (1-100 U/ml) and RA (0.1-10 microM) consistently had higher levels of enzyme activity than corresponding cells treated with IFN alone and this was true for all three types of IFNs in both cell lines. The potentiating effect of RA was dose- and time-dependent and under optimal conditions, the induction of the synthetase was synergistic between IFN-beta (10-100 U/ml) and RA (0.1-10 microM). Furthermore, pretreatment (but not posttreatment) with RA followed by subsequent treatment with IFNs preferentially induced higher levels of enzyme activity in U937 cells but not in WISH cells. In addition, our results indicated that the modulating effect of RA on IFNs did not involve interaction at the receptor level and the level of enhancement of 2-5A synthetase activity was not in parallel with either cell-growth arrest or promotion of differentiation. Lastly, the present study raises the possibility that interactions between IFNs and RA, in either a synergistic or antagonistic manner, may be mediated through amplification of the 2-5A system.