Experimental infection of Aedes albopictus (Diptera: Culicidae) Larvae with the Xiphidiocercariae of a hematolechid

Aedes albopictus larvae were exposed, either individually or in groups, to different concentrations of xiphidiocercariae of Haematoloechus sp. for parasitological studies. It was observed the acute lethal effect and some aspects of the host-parasite relationship, such as delay or progress in the host life cycle, the number and location of the metacercariae in the host, adult host malformations and the amount of metacercariae required to cause death. A delay in the cycle and a high mortality rate was in general observed. Inside the larvae, the metacercariae were found predominantly in the thorax, abdominal segments and in the head, along with a reduced number in the anal lobe and cervix. It was shown that in addition to the quantity of metacercariae present, their location in the larvae was also relevant in the determination of mortality and anomalies. Malformed adults developed from larvae containing from one to three metacercariae.     

Single eight-hour shift of light-dark cycle increases brain-derived neurotrophic factor protein levels in the rat hippocampus

We previously reported that an eight hour phase advance in the light-dark (LD) cycle increases sleep in rats. Brain-derived neurotrophic factor (BDNF) is suggested to be one of the sleep and circadian regulating factors. We have therefore observed the responses of BDNF protein in the hippocampus, cerebellum and brainstem under conditions of LD change. BDNF protein was quantitatively measured using an ELISA kit. Under an 8-h LD phase advance, the levels of hippocampal BDNF were significantly increased on the day of the phase change, while the levels in the cerebellum and brainstem remained constant. Plasma corticosterone levels were not largely affected. Thus, a single LD shift acutely affects hippocampal BDNF metabolism with no large stress response.     

HtrA1 serine protease inhibits signaling mediated by Tgfbeta family proteins

HtrA1, a member of the mammalian HtrA serine protease family, has a highly conserved protease domain followed by a PDZ domain. Because HtrA1 is a secretory protein and has another functional domain with homology to follistatin, we examined whether HtrA1 functions as an antagonist of Tgfbeta family proteins. During embryo development, mouse HtrA1 was expressed in specific areas where signaling by Tgfbeta family proteins plays important regulatory roles. The GST-pulldown assay showed that HtrA1 binds to a broad range of Tgfbeta family proteins, including Bmp4, Gdf5, Tgfbetas and activin. HtrA1 inhibited signaling by Bmp4, Bmp2, and Tgfbeta1 in C2C12 cells, presumably by preventing receptor activation. Experiments using a series of deletion mutants indicated that the binding activity of HtrA1 required the protease domain and a small linker region preceding it, and that inhibition of Tgfbeta signaling is dependent on the proteolytic activity of HtrA1. Misexpression of HtrA1 near the developing chick eye led to suppression of eye development that was indistinguishable from the effects of noggin. Taken together, these data indicate that HtrA1 protease is a novel inhibitor of Tgfbeta family members.     

Antigen, antibody and immune complex detection in serum samples from rats experimentally infected with Strongyloides venezuelensis

In order to establish an antigen, antibody and immune complex detection by enzyme-linked immunosorbent assay (ELISA) in serum samples, normal or immunocompromised Wistar rats experimentally infected with Strongyloides venezuelensis were used. The microtitre plates were coated with IgG anti-S. venezuelensis for antigen and immune complex detection and with alkaline parasite extract for antibody detection. Analysis revealed at least 12.5 μg/mL of S. venezuelensis specific antigens in serum samples. Assay for antigen detection was not a good approach for evaluating infection in normal or immunocompromised rats. In normal rats IgG specific for S. venezuelensis was preferentially detected during the first 13 days post-infection (p.i.) and immune complex detection was significantly reduced in 21 p.i. day. On the other hand, in immunocompromised rats, IgG and immune complex were detected during the entire kinetic (5, 8, 13 and 21 p.i). These results suggest that immune complex screening seems to be an alternative for early strongyloidiasis diagnosis in immunocompromised individuals.     

HLA-A*0206 with TLR3 Polymorphisms Exerts More than Additive Effects in Stevens-Johnson Syndrome with Severe Ocular Surface Complications

Background

Stevens-Johnson syndrome (SJS) is an acute inflammatory vesiculobullous reaction of the skin and mucosa, often including the ocular surface, and toxic epidermal necrolysis (TEN) occurs with its progression. Although SJS/TEN is thought to be initiated by certain types of medication coupled with possible infection. In the present study we examined the multiplicative interaction(s) between HLA-A*0206 and 7 Toll-like receptor 3 (TLR3) Single-nucleotide polymorphisms (SNPs) in patients with SJS/TEN.

Principal Findings

We analyzed the genotypes for HLA-A and 7 TLR3 SNPs in 110 Japanese SJS/TEN patients with severe ocular complications and 206 healthy volunteers to examine the interactions between the two loci. We found that HLA-A*0206 exhibited a high odds ratio for SJS/TEN (carrier frequency: OR = 5.1; gene frequency: OR = 4.0) and that there was a strong association with TLR3 rs.5743312T/T SNP (OR = 7.4), TLR3 rs.3775296T/T SNP (OR = 5.8), TLR3 rs.6822014G/G SNP (OR = 4.8), TLR3 rs.3775290A/A SNP (OR = 2.9), TLR3 rs.7668666A/A SNP (OR = 2.7), TLR3 rs.4861699G/G SNP (OR = 2.3), and TLR3 rs.11732384G/G SNP (OR = 1.9). There was strong linkage disequilibrium (LD) between rs.3775296 and rs.5743312 and between rs.7668666 and rs.3775290. The results of interaction analysis showed that the pair, HLA-A*0206 and TLR3 SNP rs3775296T/T, which exhibited strong LD with TLR3 rs.5743312, exerted more than additive effects (OR = 47.7). The other pairs, HLA-A*0206 and TLR3 rs.3775290A/A SNP (OR = 11.4) which was in strong LD with TLR3 rs7668666A/A SNP, and TLR3 rs4861699G/G SNP (OR = 7.6) revealed additive effects. Moreover, the combination HLA-A*0206 and TLR3 rs3775296T/T was stronger than the TLR3 rs6822014G/G and TLR3 rs3775290A/A pair, which reflected the interactions within the TLR3 gene alone.

Significance

By interaction analysis, HLA-A*0206 and TLR3 SNP rs3775296T/T, which were in strong LD with TLR3 SNP rs5743312T/T, manifested more than additive effects that were stronger than the interactions within the TLR3 gene alone. Therefore, multiplicative interactions of HLA-A and TLR3 gene might be required for the onset of SJS/TEN with ocular complications.     

Glutathione peroxidase 4 is required for maturation of photoreceptor cells

Oxidative stress is implicated in the pathologies of photoreceptor cells, and the protective role of antioxidant enzymes for photoreceptor cells have been well understood. However, their essentiality has remained unknown. In this study we generated photoreceptor-specific conditional knock-out (CKO) mice of glutathione peroxidase 4 (GPx4) and showed the critical role of GPx4 for photoreceptor cells. In the wild-type retina the dominant GPx4 expression was in the mitochondria, indicating the mitochondrial variant was the major GPx4 in the retina. In the GPx4-CKO mice, although photoreceptor cells developed and differentiated into rod and cone cells by P12, they rapidly underwent drastic degeneration and completely disappeared by P21. The photoreceptor cell death in the GPx4-CKO mice was associated with the nuclear translocation of apoptosis-inducing factor (AIF) and TUNEL-positive cells. Photoreceptor cells before undergoing apoptosis (P11) exhibited decreased mitochondrial biomass, decreased number of connecting cilia, as well as disorganized structure of outer segments. These findings indicate that GPx4 is a critical antioxidant enzyme for the maturation and survival of photoreceptor cells.     

SSCP Screening of the Dihydropyrimidine Dehydrogenase Gene Polymorphisms of the Japanese Population Using a Semi-automated Electrophoresis Unit

The single-strand conformation polymorphism (SSCP) procedure has been applied in routine testing for hereditary diseases. Temperature, running buffer, gel composition, and fragment length can influence its sensitivity. Mutation detection in the clinical setting depends on the development of automated technology, especially for large genes, such as the dihydropyrimidine dehydrogenase (DPYD) gene, which codes the initial, rate-limiting enzyme in the catabolism of 5-fluorouracil (5FU). The authors have optimized the condition of SSCP with an automated system (GenePhor system, GE Healthcare UK Ltd.) to screen genetic polymorphisms in the DPYD gene. The efficiency of the method was evaluated using 21 positive controls (DNA samples with polymorphisms in the DPYD gene, previously characterized) and DNA samples from 35 Japanese. Results showed that the use of three different running buffers (pH 7.4, 8.3, and 9.0) in combination with other optimized conditions (10% polyacrylamide gel, 60-90 min at constant 900 V at 5 degrees C) resulted in a high polymorphism detection rate (95.3%), which was considered appropriate for routine screening. Therefore, this strategy could be useful for pharmacogenetic studies on 5FU.     

应用冰冻蚀刻技术观察北方禾谷花叶病毒

冰冻蚀刻电子显微镜技术,在生物医学研究方面应用较多,但是在植物病毒研究方面报道极少。1985年我们对日本国小麦上的北方禾谷花叶病毒(Northern cereal mosaic virus简称NCMV)弹状病毒粒子进行了试验,获得了比较满意的结果。