Effects of gestational exposure to 1.95‐GHz W‐CDMA signals for IMT‐2000 cellular phones: Lack of embryotoxicity and teratogenicity in rats

The present study was designed to evaluate whether gestational exposure to an EMF targeting the head region, similar to that from cellular phones, might affect embryogenesis in rats. A 1.95‐GHz wide‐band code division multiple access (W‐CDMA) signal, which is one applied for the International Mobile Telecommunication 2000 (IMT‐2000) system and used for the freedom of mobile multimedia access (FOMA), was employed for exposure to the heads of four groups of pregnant CD(SD) IGS rats (20 per group) for gestational days 7–17. The exposure was performed for 90 min/day in the morning. The spatial average specific absorption rate (SAR) for individual brains was designed to be 0.67 and 2.0 W/kg with peak brain SARs of 3.1 and 7.0 W/kg for low (group 3) and high (group 4) exposures, respectively, and a whole‐body average SAR less than 0.4 W/kg so as not to cause thermal effects due to temperature elevation. Control and sham exposure groups were also included. At gestational day 20, all dams were killed and fetuses were taken out by cesarean section. There were no differences in maternal body weight gain. No adverse effects of EMF exposure were observed on any reproductive and embryotoxic parameters such as number of live (243–271 fetuses), dead or resorbed embryos, placental weights, sex ratios, weights or external, visceral or skeletal abnormalities of live fetuses. Bioelectromagnetics 30:205–212, 2009. © 2008 Wiley‐Liss, Inc.     

Localization of laminin α3B chain in vascular and epithelial basement membranes of normal human tissues and its down-regulation in skin cancers

The basement membrane (BM) proteins laminins, which consist of alpha, beta and gamma chains, play critical roles in the maintenance of tissue structures. One of laminin alpha chains, alpha3 has two isoforms, the truncated form alpha3A and the full-sized form alpha3B. In contrast to alpha3A laminins, little is known about alpha3B laminins. To show the histological distribution of the laminin alpha3B chain, we prepared alpha3B-specific monoclonal antibodies. Immunohistochemical analysis showed that the alpha3B chain was colocalized with the alpha3A, beta3 and gamma2 chains in the epithelial BMs of the skin, esophagus, breast and lung, suggesting the presence of laminin-3B32 (laminin-5B) and laminin-3A32 (laminin-5A). In the lung alveoli, laminin-3B32 was dominant over laminin-3A32, but vice versa in other epithelial BMs. In contrast, the BMs of blood vessels including capillaries were strongly positive for alpha3B, but almost or completely negative for alpha3A, beta3 and gamma2. alpha3B was colocalized with beta1 and gamma1 in these BMs. The alpha3B chain was scarcely detected in the vessels of malignant skin cancers, though the gamma2 and beta3 chains were highly expressed in the cancer cells. These results strongly suggest that the laminin alpha3B chain is widely expressed in vascular BMs of normal tissues, probably as laminin-3B11/3B21 (laminin-6B/7B).     

The effects of hemorrhagic shock on thyrotropin-releasing hormone and its receptors in discrete regions of rat brain

The effects of hemorrhagic shock on thyrotropin-releasing hormone (TRH) levels and its receptors were studied in different regions of the rat brain. Rats were bled for 30 min from the left femoral artery, and their mean arterial pressure was kept at 40 mmHg for the following hour. The rats were killed by decapitation. Rat brains were immediately removed and dissected into 7 regions. Hemorrhagic shock decreased TRH significantly in the frontal cortex, septum, hippocampus, and hindbrain but TRH was not changed in the striatum, hypothalamus, and midbrain. Hemorrhagic shock significantly decreased TRH receptor binding in the septum and hindbrain. Scatchard analysis of saturation isotherms of specific TRH binding showed that the decreased specific TRH binding in the hindbrain resulted not from an increase of the dissociation constant (Kd), but from a decrease in the maximum number of binding sites (Bmax). In the septum, the decrease in specific binding was due both to a decrease in Bmax and an increase in Kd. The findings indicate that TRH plays a role in the physiological response to hemorrhagic shock.     

Calcium binding to troponin C and troponin: effects of Mg2+, ionic strength and pH

Calcium binding to troponin C and troponin was examined by a metallochromic indicator method under various conditions to obtain a further understanding of the regulatory roles of these proteins in muscle contraction. Troponin C has four Ca binding sites, of which 2 sites have a high affinity of 4.5 X 10(6) M-1 for Ca2+ and the other 2 sites have a low affinity of 6.4 X 10(4) M-1 in a reaction medium consisting of 100 mM KCl, 20 mM MOPS-KOH pH 6.80 and 0.13 mM tetramethylmurexide at 20 degrees C. Magnesium also binds competitively to both the high and low affinity sites: the apparent binding constants are 1,000 M-1 and 520 M-1, respectively. Contrary to the claim by Potter and Gergely (J. Biol. Chem. 250, 4628-4633, 1975), the low affinity sites are not specific only for Ca2+. The high and low affinity sites of troponin C showed different dependence on the ionic strength: the high affinity sites were similar to GEDTA, while the low affinity sites were similar to calmodulin, which has a steeper ionic strength dependence than GEDTA. Ca binding to troponin C was not affected by change of pH between 6.5 and 7.2. Troponin I enhanced the apparent affinity of troponin C for Ca2+ to a value similar to that for troponin. Trifluoperazine also increased Ca binding to troponin C. Troponin has four Ca binding sites as does troponin C, but the affinities are so high that the precise analysis was difficult by this method. The apparent binding constants for Ca2+ and Mg2+ were determined to be 3.5 X 10(6) M-1 and 440 M-1, respectively, for low affinity sites under the same conditions as for troponin C, being independent of change in pH between 6.5 and 7.2. The competitive binding of Mg2+ to the low affinity sites of troponin is consistent with the results of Kohama (J. Biochem. 88, 591-599, 1980). The estimate for the high affinity sites is compatible with the reported results.     

cDNA sequence and expression of a cold-responsive gene in Citrus unshiu

A cDNA clone encoding a protein (CuCOR19), the sequence of which is similar to Poncirus COR19, of the dehydrin family was isolated from the epicarp of Citrus unshiu. The molecular mass of the predicted protein was 18,980 daltons. CuCOR19 was highly hydrophilic and contained three repeating elements including Lys-rich motifs. The gene expression in leaves increased by cold stress.     

Enhanced sequence coverage in tryptic fragment analysis by two-dimensional HPLC/MS using a monolithic silica capillary column

The HPLC/MS system, in which a monolithic silica capillary column is directly connected to an electronspray-ionization mass spectrometer, showed superior performance at high mobile phase linear velocity. A two-dimensional (2D) HPLC/MS system was established, using an ion-exchange particle-packed capillary column at the first dimension and a monolithic silica capillary column at the second dimension. In an analysis of tryptic fragments from bovine serum albumin, an 81% sequence coverage, obtained by the 2D-HPLC/MS system, increased by 23% as compared to a 1D-HPLC/MS system. This 2D-HPLC/MS system using a monolithic silica capillary column should be useful for enhancing sequence coverage of tryptic fragments in proteomics.     

Expression of the SNF1 gene from Candida tropicalis is required for growth on various carbon sources, including glucose

SNF1 of Saccharomyces cerevisiae is an essential gene for the derepression of glucose repression. A homolog of SNF1 (CtSNF1) was isolated from an n-alkane-assimilating diploid yeast, Candida tropicalis. CtSNF1 could complement the snf1 mutant of S. cerevisiae. The previously published method for introducing the exogenous DNA into C. tropicalis was employed to construct SNF1/ snf1 heterozygote and snf1/snf1 homozygote strains. The successfully constructed SNF1/snf1 heterozygote was named KO-1. Disruption of the second CtSNF1 allele was unsuccessful, suggesting that CtSNF1 might be essential for cell viability. Therefore, in order to control the expression of CtSNF1, a strain (named KO-1G) in which the promoter region of CtSNF1 was replaced with the GAL10 promoter of C. tropicalis was constructed, and the growth of strains KO-1 and KO-1G was compared with that of the parental strain. The growth of strain KO-1 on glucose, sucrose, or acetate did not differ from the growth of the parental strain, but strain KO-1 showed a slight growth retardation on n-alkane. The growth of strain KO-1G on galactose was normal, but the cells stopped growing when transferred to glucose-, acetate-, or n-alkane-containing medium. Northern blot analysis against mRNA from the n-alkane-grown KO-1G strain demonstrated a close relationship between the presence of CtSNF1 mRNA and the growth of the cells, indicating that CtSNF1 is essential for cell viability. Moreover, mRNA levels of isocitrate lyase, which is localized in peroxisomes of C. tropicalis, were significantly affected by the level of CtSNF1 mRNA. Received: 3 May 1999 / Accepted: 14 July 1999     

Systematic analysis of SNARE localization in the filamentous fungus Aspergillus oryzae

In spite of their great importance for both applied and basic biology, studies on vesicular trafficking in filamentous fungi have been so far very limited. Here, we identified 21 genes, which might be a total set, encoding putative SNARE proteins that are key factors for vesicular trafficking, taking advantage of available whole genome sequence in the filamentous fungus Aspergillus oryzae. The subsequent systematic analysis to determine the localization of putative SNAREs using EGFP-fused chimeras revealed that most putative SNAREs show similar subcellular distribution to their counterparts in the budding yeast. However, there existed some characteristic features of SNAREs in A. oryzae, such as SNARE localization at/near the septum and the presence of apparently non-redundant plasma membrane Qa-SNAREs. Overall, this analysis allowed us to provide an overview of vesicular trafficking and organelle distribution in A. oryzae.