Faculty Bibliography

Group II chaperonins, found in Archaea and in the eukaryotic cytosol, act independently of a cofactor corresponding to GroES of group I chaperonins. Instead, the helical protrusion at the tip of the apical domain forms a built-in lid of the central cavity. Although many studies on the lid's conformation have been carried out, the conformation in each step of the ATPase cycle remains obscure. To clarify this issue, we examined the effects of ADP-aluminum fluoride (AlFx) and ADP-beryllium fluoride (BeFx) complexes on alpha-chaperonin from the hyperthermophilic archaeum, Thermococcus sp. strain KS-1. Biochemical assays, electron microscopic observations, and small angle x-ray scattering measurements demonstrate that alpha-chaperonin incubated with ADP and BeFx exists in an asymmetric conformation; one ring is open, and the other is closed. The result indicates that alpha-chaperonin also shares the inherent functional asymmetry of bacterial and eukaryotic cytosolic chaperonins. Most interestingly, addition of ADP and BeFx induced alpha-chaperonin to encapsulate unfolded proteins in the closed ring but did not trigger their folding. Moreover, alpha-chaperonin incubated with ATP and AlFx or BeFx adopted a symmetric closed conformation, and its functional turnover was inhibited. These forms are supposed to be intermediates during the reaction cycle of group II chaperonins.

Homeostatic proliferation of T cells leads to the generation of effector/memory cells, which have the potential to cause harm to the host. The role of Tregs in the control of homeostatic proliferation is unclear. In this study we utilized mice that either harbor or lack Tregs as recipients of monoclonal or polyclonal T cells. We observed that while Tregs completely prevented cell division of T cells displaying low affinity for self ligands, they had a less marked, albeit significant, effect on cell cycle entry of T cells displaying higher affinity. The presence of Tregs resulted in a lower accumulation of T cells, enhanced apoptosis, and impaired differentiation to a cytokine-producing state. We conclude that Tregs play a major role in the control of homeostatic proliferation

Cardiolipin is a unique mitochondrial phospholipid with an atypical fatty acid profile, but the significance of its acyl specificity has not been understood. We explored the enormous combinatorial diversity among cardiolipin species, which results from the presence of four fatty acids in each molecule, by integrated use of high-performance liquid chromatography, mass spectrometry, diacylglycerol species analysis, fatty acid analysis, and selective cleavage of fatty acids by phospholipase A2. The most abundant cardiolipin species from various organisms and tissues (human heart, human lymphoblasts, rat liver, Drosophila, sea urchin sperm, yeast, mung bean hypocotyls) contained only one or two types of fatty acids, which generated a high degree of structural uniformity and molecular symmetry. However, an exception was found in patients with Barth syndrome, in whom an acyltransferase deficiency led to loss of acyl selectivity and formation of multiple molecular species. These results suggest that restriction of the number of fatty acid species, rather than the selection of a particular kind of fatty acid, is the common theme of eukaryotic cardiolipins. This limits the structural diversity of the cardiolipin species and creates molecular symmetry with implications for the stereochemistry of cardiolipin

BACKGROUND: Mosquitoes were collected in Heilongjiang province in 2002, four virus strains were isolated by inoculation of homogenates onto BHK cell lines. The viruses were identified. Multiple alignment and phylogenetic analysis were carried out by Clustal X (1.8) program.Amino acid (AA) analysis was carried out by GENEDOS (3.2). RESULTS: Biological characters of four newly isolated strains were examined and it was found that all of them could produce cytopathogenic effect (CPE) in BHK cells, killing sucking mice. Serological tests showed that all of these stains reacted positively to JEV antibodies. PrM and E gene regions were amplified and sequenced. Phylogenic analysis showed that all the newly isolated JEV strains belong to genotype III. Using the vaccine strains (SA14-14-2) as control, analysis of the E gene of the new strains and two JEV strains (47, Ha-3) isolated previously from Heilongjiang province showed that these new strains' nucleotide sequence had a homology of up to 99.9% and the amino acid sequence homology up to 99.8%, respectively. Compared with the standard JE vaccine strain SA-14-14-2 and the four new strains, the nucleotide sequence homology was 97.3% and amino acid sequence homology was between 96.8% and 97.0%, respectively. Compared with vaccine strain, there were seven common variations in all the four newly isolated strains. CONCLUSION: Four JE virus strains were isolated in Heilongjiang province. As compared to the vaccine strain, six variations were found in the newly isolated strains at the eight sites relevant to the virulence of the virus.

Respiratory dysfunction during sepsis is common. However, although lung function can often be adequately supported, death frequently results from cardiovascular collapse. Despite intense investigation, the mechanism underlying the myocardial dysfunction of sepsis remains unclear. Macrophage migration inhibitory factor (MIF), an important cytokine released in sepsis and the acute respiratory distress syndrome, is a known cardiac depressant. We hypothesized that MIF released from the lung results in myocardial dysfunction during sepsis. In murine models of polymicrobial sepsis, we demonstrate a significant increase in the lungs of total and lavagable MIF between 20 and 30 h post induction of sepsis. At 30 h post sepsis, the lungs released MIF into the pulmonary circulation, increasing the plasma concentration by up to 51% in a single pass. Exogenous MIF, instilled into the lungs, increased alveolar keratinocyte-derived chemokine (KC), Macrophage inflammatory protein-2 (MIP2), and tumor necrosis factor alpha (TNFalpha) at 3 h, and plasma KC and MIP2 at 6 h postinstillation. This was associated with an increase in p38 mitogen-activated protein kinase and c-Jun N-terminal kinase phosphorylation. Because changes in mitogen-activated protein kinase activation can lead to myocardial depression, these data suggest that MIF released from the lungs may be responsible, at least in part, for the cardiac dysfunction seen in the late stages of sepsis

The nodes of Ranvier are regularly spaced gaps between myelin sheaths that are markedly enriched in voltage-gated sodium channels and associated proteins. Myelinating glia play a key role in promoting node formation, although the requisite glial signals remain poorly understood. In this study, we have examined the expression of glial proteoglycans in the peripheral and central nodes. We report that the heparan sulfate proteoglycan, syndecan-3, becomes highly enriched with PNS node formation; its ligand, collagen V, is also concentrated at the PNS nodes and at lower levels along the abaxonal membrane. The V1 isoform of versican, a chondroitin sulfate proteoglycan, is also present in the nodal gap. By contrast, CNS nodes are enriched in versican isoform V2, but not syndecan-3. We have examined the molecular composition of the PNS nodes in syndecan-3 knockout mice. Nodal components are normally expressed in mice deficient in syndecan-3, suggesting that it has a nonessential role in the organization of nodes in the adult. These results indicate that the molecular composition and extracellular environment of the PNS and CNS nodes of Ranvier are significantly distinct

The discovery of long-lived epithelial stem cells in the bulge region of the hair follicle led to the hypothesis that epidermal renewal and epidermal repair after wounding both depend on these cells. To determine whether bulge cells are necessary for epidermal renewal, here we have ablated these cells by targeting them with a suicide gene encoding herpes simplex virus thymidine kinase (HSV-TK) using a Keratin 1-15 (Krt1-15) promoter. We show that ablation leads to complete loss of hair follicles but survival of the epidermis. Through fate-mapping experiments, we find that stem cells in the hair follicle bulge do not normally contribute cells to the epidermis which is organized into epidermal proliferative units, as previously predicted. After epidermal injury, however, cells from the bulge are recruited into the epidermis and migrate in a linear manner toward the center of the wound, ultimately forming a marked radial pattern. Notably, although the bulge-derived cells acquire an epidermal phenotype, most are eliminated from the epidermis over several weeks, indicating that bulge stem cells respond rapidly to epidermal wounding by generating short-lived 'transient amplifying' cells responsible for acute wound repair. Our findings have implications for both gene therapy and developing treatments for wounds because it will be necessary to consider epidermal and hair follicle stem cells as distinct populations

BACKGROUND: To study the molecular characteristics of YN92-4 strain isolated from mosquitoes in Yunnan Province and define its classification. METHODS: The S segment of YN92-4 strain was amplified and sequenced by 2 different sets of primers. The phylogenic tree of S fragment was constructed by Phylip bio-software. The amino acid sequences of N and NSs proteins were also studied. RESULTS: YN92-4 strain could be amplified by 2 sets of primers respectively, S segment showed a highest homology with Batai virus (X73464), reached 96.4%, the homology of protein N and NSs amio-acid sequence with Batai virus was 99.1% and 98% respectively. CONCLUSION: The YN92-4 strain belongs to Batai virus, this is the first report of molecular biological identification of Batai virus in China.

BACKGROUND: To survey arboviruses in Yunnan province. METHODS: Mosquitoes were collected from Yunnan Province in 2002 and 2004. Virus strains were isolated by the inoculation of homogenates of the mosquitoes onto BHK cell line. The isolated strains and their molecular biological characteristics were identified by real-time PCR, reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescent antibody technique. RESULTS: Twelve strains of viruses producing CPE in BHK cells were isolated from 4810 mosquitoes. All the 12 isolates were identified to be Japanese encephalitis viruses. Genotype analysis showed the new virus (DL-0437 strain) belonged to genotype III. CONCLUSION: Twelve strains of Japanese encephalitis viruses were isolated from mosquito pools collected in Yunnan. It was the first isolation of genotype III Japanese encephalitis viruses in Yunnan Province in recent years.