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.     

Characterization of a regulatory gene, <Emphasis Type="Italic">aveR</Emphasis>, for the biosynthesis of avermectin in <Emphasis Type="Italic">Streptomyces avermitilis</Emphasis>

Avermectin is an important macrocyclic polyketide produced by Streptomyces avermitilis and widely used as an anthelmintic agent in the medical, veterinary, and agricultural fields. The avermectin biosynthetic gene cluster contains aveR, which belongs to the LAL-family of regulatory genes. In this study, aveR was inactivated by gene replacement in the chromosome of S. avermitilis, resulting in the complete loss of avermectin production. The aveR mutant was unable to convert an avermectin intermediate to any avermectin derivatives, and complementation by intact aveR and its proper upstream region restored avermectin production in the mutant, suggesting that AveR is a positive regulator controlling the expression of both polyketide biosynthetic genes and postpolyketide modification genes in avermectin biosynthesis. Despite the general concept that an increased amount of a positive pathway-specific regulator leads to higher production, a higher amount of aveR resulted in complete loss of avermectin, indicating that there is a maximum threshold concentration of aveR for the production of avermectin.     

Metabolism of hydroxylated PCB congeners by cloned laccase isoforms

The white-rot fungus T. versicolor UAMH 8272 produced two groups of laccases, each of which included several isoforms showing different isoelectric points (pI). Group 1 and group 2 laccases, respectively, displayed higher pI 5–6 and lower pI 3–4. Of the four cloned full-length laccase cDNAs, Lac 1 and Lac 4 were expressed in the heterologous protein expression system using Aspergillus oryzae. The measured pI of each Lac 1 and Lac 4 expressed in A. oryzae was lower than that of pI predicted from the amino acid composition. With this regard, isoelectric focusing of Lac 1 showed the presence of multiple protein bands in the 3.0–4.0 pI range, although the predicted pI value of Lac 1 was 4.7. Similarly, Lac 4 exhibited a pI value which was lower than that predicted (3.6 vs. 4.3, respectively). In all tested hydroxyPCBs, higher chlorinated hydroxyPCBs were less susceptible to in vitro degradation by laccase than lower chlorinated hydroxyPCBs. Although Lac 4 showed a generally higher activity than Lac 1, the two laccases were characterized by quite different substrate specificity toward two hydroxy-tetrachlorobiphenyl congeners. Two metabolites were obtained from the metabolism of hydroxy-pentachlorobiphenyl: a ten chlorine-substituted dimer with a C–O bond, and one with a C–C bond.     

Overexpression of a rice gene encoding a small C2 domain protein OsSMCP1 increases tolerance to abiotic and biotic stresses in transgenic Arabidopsis

Plant growth and crop production are limited by environmental stress. We used a large population of transgenic Arabidopsis expressing rice full-length cDNAs to isolate the rice genes that improve the tolerance of plants to environmental stress. By sowing T2 seeds of the transgenic lines under conditions of salinity stress, the salt-tolerant line R07047 was isolated. It expressed a rice gene, OsSMCP1, which encodes a small protein with a single C2 domain, a Ca²⁺-dependent membrane-targeting domain. Retransformation of wild-type Arabidopsis revealed that OsSMCP1 is responsible for conferring the salt tolerance. It is particularly interesting that R07047 and newly constructed OsSMCP1-overexpressing Arabidopsis showed enhanced tolerance not only to high salinity but also to osmotic, dehydrative, and oxidative stresses. Furthermore, R07047 showed improved resistance to Pseudomonas syringae. The OsSMCP1 expression in rice is constitutive. Particle-bombardment-mediated transient expression analysis revealed that OsSMCP1 is targeted to plastids in rice epidermal cells. It induced overexpression of several nuclear encoded genes, including the stress-associated genes, in transgenic Arabidopsis. No marked morphological change or growth retardation was observed in R07047 or retransformants. For molecular breeding to improve the tolerance of crops against environmental stress, OsSMCP1 is a promising candidate.     

Absolute configuration of (+)-pinoresinol 4-O-[6″-O-galloyl]-β-d-glucopyranoside, macarangiosides E, and F isolated from the leaves of Macaranga tanarius

A lignan glucoside, (+)-pinoresinol 4-O-[6″-O-galloyl]-β-d-glucopyranoside (1), and two megastigmane glucosides, named macarangiosides E and F (2, 3), together with 15 known compounds (4–18) were isolated from leaves of Macaranga tanarius (L.) Müll.-Arg. (Euphorbiaceae). Their structures were elucidated by spectroscopic and chemical analyses. In addition, the absolute stereochemistry of macarangiosides B and C isolated previously from the same plant was also determined for the first time. Compounds 1 and 2 were galloylated on glucose and possessed potent DPPH radical-scavenging activity.     

Nod Factor/Nitrate-Induced CLE Genes that Drive HAR1-Mediated Systemic Regulation of Nodulation

Host legumes control root nodule numbers by sensing externaland internal cues. A major external cue is soil nitrate, whereasa feedback regulatory system in which earlier formed nodulessuppress further nodulation through shoot–root communicationis an important internal cue. The latter is known as autoregulationof nodulation (AUT), and is believed to consist of two long-distancesignals: a root-derived signal that is generated in infectedroots and transmitted to the shoot; and a shoot-derived signalthat systemically inhibits nodulation. In Lotus japonicus, theleucine-rich repeat receptor-like kinase, HYPERNODULATION ABERRANTROOT FORMATION 1 (HAR1), mediates AUT and nitrate inhibitionof nodulation, and is hypothesized to recognize the root-derivedsignal. Here we identify L. japonicus CLE-Root Signal 1 (LjCLE-RS1)and LjCLE-RS2 as strong candidates for the root-derived signal.A hairy root transformation study shows that overexpressingLjCLE-RS1 and -RS2 inhibits nodulation systemically and, furthermore,that the systemic suppression depends on HAR1. Moreover, LjCLE-RS2expression is strongly up-regulated in roots by nitrate addition.Based on these findings, we propose a simple model for AUT andnitrate inhibition of nodulation mediated by LjCLE-RS1, -RS2peptides and the HAR1 receptor-like kinase.     

Distinct genotype and antigenicity among genogroup II sapoviruses

SaV, a pathogen of acute gastroenteritis, is divided into five genogroups, GI to GV. However, the relation between SaV antigenicity and genetic clusters is not fully understood. We have recently identified two GII SaV strains, Mc10 and C12, which are grouped into the same cluster based on the polymerase but are grouped into distinct clusters based on the capsid. To evaluate the difference in antigenicity between these two strains, VLP were expressed in mammalian cells. An antigen ELISA demonstrated for the first time that strains in the same GII SaV genogroup, but within different clusters, have distinct antigenicities.     

Age-dependent expression of hephaestin in the brain of ceruloplasmin-deficient mice

Aceruloplasminemia is an autosomal recessive disorder caused by mutations in the ceruloplasmin (CP) gene. It is characterized by iron accumulation in the brain and in visceral organs. However, little is known about the mechanism of iron transport in these regions. Adult CP null (CP^−/−) mice show increased iron deposition in several regions of brain, such as the cerebellum and brainstem. In this study, we investigated the expression of the ceruloplasmin homolog hephaestin (Heph) in the brain of CP^−/− mice as a function of age. In the cerebral cortex and caudate putamen of 80-week-old CP^−/− mice, the expression of Heph increased significantly whilst iron levels remain normal [Patel BN, Dunn RJ, Jeong SY, Zhu Q, Julien JP, David S. Ceruloplasmin regulates iron levels in the CNS and prevents free radical injury. J Neurosci 2002;22(15):6578–6], indicating that Heph might compensate for the loss of CP. In contrast, the substantia nigra and cerebellum of 80-week-old CP^−/− mice accumulate iron but do not express high levels or significant decrease of Heph, suggesting that Heph does not replace CP in these regions. These data suggest that Heph may compensate for the loss of CP in a region-specific manner.     

Reduced proliferative activity of primary POMGnT1-null myoblasts in vitro

Protein O-linked mannose β1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) is an enzyme that transfers N-acetylglucosamine to O-mannose of glycoproteins. Mutations of the POMGnT1 gene cause muscle–eye–brain (MEB) disease. To obtain a better understanding of the pathogenesis of MEB disease, we mutated the POMGnT1 gene in mice using a targeting technique. The mutant muscle showed aberrant glycosylation of α-DG, and α-DG from mutant muscle failed to bind laminin in a binding assay. POMGnT1^?/? muscle showed minimal pathological changes with very low-serum creatine kinase levels, and had normally formed muscle basal lamina, but showed reduced muscle mass, reduced numbers of muscle fibers, and impaired muscle regeneration. Importantly, POMGnT1^?/? satellite cells proliferated slowly, but efficiently differentiated into multinuclear myotubes in vitro. Transfer of a retrovirus vector-mediated POMGnT1 gene into POMGnT1^?/? myoblasts completely restored the glycosylation of α-DG, but proliferation of the cells was not improved. Our results suggest that proper glycosylation of α-DG is important for maintenance of the proliferative activity of satellite cells in vivo.