Polymerization of the Tryptophanyl tRNA Synthetase Complex with Tryptophan

To understand the mechanism of mutual recognition between aminoacyl tRNA synthetases (EC 6.1.1) and tRNAs, it is important to obtain more information about the structure of these enzymes. X-ray crystallography offers one approach, but although several aminoacyl tRNA synthetases have been isolated in very pure form¹ and crystallization of tryptophanyl² and seryl³ tRNA synthetases has been reported, no crystals were available that were suitable for structural analysis. Only very recently have Rymo and Lagerkvist⁴ described the formation of crystals of yeast lysyl tRNA synthetase which are apparently suitable for further X-ray analysis. Here we deal with the phenomenon of polymerization of the tryptophanyl tRNA synthetase complex with tryptophan in the form of rod-like particles and the subsequent formation of para-crystalline aggregates.     

Murine model for immunoprophylaxis of cytomegalovirus infection. I. Efficacy of immunization.

Murine cytomegalovirus was utilized as a model for human cytomegalovirus, which had no experimental animal, to study immunoprophylaxis of the cytomegalovirus infections. (1) Murine cytomegalovirus (MCMV) serially propagated in mouse embryonic fibroblasts had lost pathogenicity for weanling mice including neonatally thymectomized mice. (2) The cell culture-adapted MCMV was effective as a "live, attenuated virus vaccine" against challenge by virulent, mouse-passaged MCMV. (3) The immunization via intraperitoneal route protected mice from every parameter of MCMV infection. These included clinical signs, virus replication, histopathology and mortality. (4) The protective immunity was active against the virulent MCMV which was not neutralized by the rabbit anti-attenuated MCMV serum.     

Induction of apoptosis of T cells by infecting mice with murine cytomegalovirus.

Cytomegalovirus (CMV) is associated with several lymphocyte dysfunctions, but the precise mechanisms of the dysfunctions are still unclear. To elucidate the mechanisms, a cell cycle-DNA content analysis was performed on splenic T cells of murine CMV (MCMV)-infected BALB/c mice. T cells from mice infected with 3 x 10(3) PFU of MCMV contained a higher percentage of hypodiploid nuclei after 12 or 24 h of culture than those from naive mice. T cells from infected mice also contained a larger amount of fragmented DNA. Taken together, these results suggested that infection with MCMV induced the apoptotic cell death of T cells. This induction of apoptosis accounted for the dysfunction of lymphocytes, at least partially. Flow cytometric analysis showed that T cells as well as B cells from MCMV-infected mice expressed an augmented level of Fas antigen, an apoptosis-associated cell surface molecule, which might be the cause of the apoptosis of cells. T cells from MCMV-infected C57BL/6-lpr/lpr mice with mutations at the lpr/fas locus, however, also showed a substantial level of apoptosis, which was reproducibly lower than that seen in C57BL/6 mice. Therefore, it was suggested that the Fas-mediated pathway contributed to but was not sufficient for the induction of apoptosis and that mechanisms other than the Fas-associated pathway were also involved in the induction of apoptosis.     

应激刺激对大鼠下丘脑血管升压素mRNA水平的影响

实验在给予慢性应激刺激的Ｓｐｒａｇｕｅ Ｄａｗｌａｙ雄性大鼠中进行,用核酸斑点杂交技术观察大鼠下丘脑组织中血管升压素（ＡＶＰ）ｍＲＮＡ水平变化,用异羟基洋地黄毒甙（ＤＩＧ）标记的２６个碱基长寡聚核苷酸作为检测探针。结果观察到：在给予电击足底结合噪声的应激刺激之后,尾动脉收缩压逐渐升高,到刺激第５天,刺激组与对照组动物之间尾动脉收缩压差别有统计学显著意义;到刺激第９天,刺激组尾动脉收缩压达最高值;以     

以HSV-1扩增子载体构建的新型重组AAV载体包装系统

将缺失两端ITR的AAV -2基因组克隆于HSV -1扩增子载体获得了质粒pHSV AAV .以HSV- 1tsK株为辅助病毒感染转染了该质粒的Vero细胞 ,可获得一种具有包装重组AAV质粒能力的混合毒种 .连续传代可使其包装能力迅速升高 ,至 5～ 6代达到最高并趋于平稳 .此混合毒种中 ,含有包装了多拷贝AAV -2基因组的复制缺陷性假型HSV- 1病毒 ,它可表达AAV -2编码的复制与包装所需的各种反式蛋白 ;同时也含有HSV -1tsK病毒 ,它提供AAV -2复制与包装所需的全部辅助病毒功能 .实验结果也表明 ,HSV -1tsK病毒的复制为混合毒种辅助重组AAV载体的包装所必需 .这项研究首次报道了一种全新的重组AAV载体包装系统 ,与传统的双质粒共转染、腺病毒辅助包装方案相比 ,本系统简便易行 ,并明显提高了重组AAV的包装效率 .     

KILLER WHALE (ORCINUS ORCA) AUDITORY EVOKED POTENTIALS TO RHYTHMIC CLICKS

Temporal auditory mechanisms were measured in killer whales ( Orcinus orca ) by recording auditory evoked potentials (AEPs) to clicks. Clicks were presented at rates from 10/sec to 1,600/sec. At low rates, clicks evoked an AEP similar to the auditory brainstem response (ABR) of other odontocetes; however, peak latencies of the main waves were 3–3.7 msec longer than in bottlenose dolphins. Fourier analysis of the ABR showed a prominent peak at 300–400 Hz and a smaller one at 800–1,200 Hz. High-rate click presentation (more than 100/sec) evoked a rate-following response (RFR). The RFR amplitude depended little on rate up to 400/sec, decreased at higher rates and became undetectable at 1,120/sec. Fourier analysis showed that RFR fundamental amplitude dependence on frequency closely resembled the ABR spectrum. The fundamental could follow clicks to around 1,000/sec, although higher harmonics of lower rates could arise at frequencies as high as 1,200 Hz. Both RFR fundamental phase dependence on frequency and the response lag after a click train indicated an RFR group delay of around 7.5 msec. This corresponds to the latency of ABR waves PIII-NIV, which indicates the RFR originates as a rhythmic, overlapping ABR sequence. The data suggest the killer whale auditory system can follow high click rates, an ability that may have been selected for as a function of high-frequency hearing and the use of rapid clicks in echolocation.     

Passive Hemagglutination Assays for the Detection of Antibodies to Herpes Viruses

A simple and effective method for the detection of antibodies to herpes simplex virus (HSV), human cytomegalovirus (HCMV) and varicella-zoster virus (VZV), has been established using the passive hemagglutination assay (PHA) in combination with viral specific glycoproteins. The results obtained with the PHA were compared with those from neutralization (NT) and complement fixation (CF) tests. The PHA test for each of the herpes viruses appears to compare favorably with the other assays tested. The specificity and sensitivity of HSV PHA to NT were 100%, whereas the specificity and sensitivity of HSV CF test to NT were 98% and 100%, respectively. For HCMV, the specificity and sensitivity of PHA to NT and PHA to CF were 100%. Similarly, the specificity and sensitivity of VZV PHA to NT were 100%. Because of the low sensitivity of the VZV CF, the sensitivity of CF to NT was 83%. Furthermore, the range of antibody titers and their absolute levels obtained in the PHAs were significantly greater than those in the NT and CF tests.     

Molecular characterization and functional expression of opioid receptor-libe_1 receptor

INTRODUCTIONOpioidactsinthecentralandperipheralnervoussystem(CNSandPNS)to'producenumerouspharmacologicaleffects.Repetitiveorcontinuoususeofopioids,however,causesdrugtoleranceanddependence.Threesubtypesofopioidreceptors,termedp)6,andK,havebeencloned.TheyarecoupledtotheinhibitoryGproteinandnegativelyregulateadenylylcyclasell].RecentlyanewG-proteincoupledreceptortermedopioidreceptor-likereceptor(ORLI)whichbelongstothenewlycharacterizedopioidreceptorsubfamilyhadbeenclonedfromhumanbrainst…     

Eight polymorphic microsatellite loci for the critically endangered crested ibis,Nipponia nippon (Ciconiiformes: Threskiornithidae)

The Chinese crested ibis, Nipponia nippon, is a critically endangered bird. The current population of this species has developed from four wild individuals rediscovered in 1981. Given its conservation status, there is considerable interest in assessing the genetic diversity and individual relatedness in this species. For this purpose, a set of eight polymorphic di‐ or trinucleotide microsatellite loci was developed for the crested ibis. The expected heterozygosity at these loci ranges from 0.01 to 0.50, with less than four alleles being observed at individual loci, a reflection of the serious population bottleneck experienced by this species.     

The localization of CD3, CD79a,CD68 and S100 protein immunoreactive cells in hemal nodes of Saanen goat (Capra hircus)

We investigated the structure of hemal nodes in Saanen goats using immunohistochemical staining. We examined the distribution of CD3 positive T lymphocytes, CD79a positive B lymphocytes, CD68 positive macrophages and S100 protein positive follicular dendritic cells. Hemal nodes of six healty adult female goats were used. Hemal nodes were removed from the thoracic and abdominal cavities. The oval to round hemal nodes were observed especially between the abdominal aorta and vena cava, and near the kidneys and adrenal glands. Tissue sections were stained with Crossmon’s modified triple stain to demonstrate general histological structure. The avidin-biotin-peroxidase technique using anti-CD3, anti-CD79a, anti-CD68 and anti-S100 primary antibodies was used for immunohistochemistry. Many CD3 positive T lymphocytes were found in the germinal center of the lymph follicles and in the lymphatic cords of hemal nodes; CD3 positive cells also were observed in the sinuses. CD79a and CD68 positive cells were found at the germinal center of the lymph follicles. In the lymph follicles near the subcapsular sinuses, CD79a and CD68 positive cells were found especially in e areas bordering the mantle zone. S100 positive cells were found in the lymph follicles, lymphatic cords and sinuses.