A bacterial vesicle-based pneumococcal vaccine against influenza-mediated secondary Streptococcus pneumoniae pulmonary infection

Streptococcus pneumoniae (Spn) is a common pathogen causing a secondary bacterial infection following influenza, which leads to severe morbidity and mortality during seasonal and pandemic influenza. Therefore, there is an urgent need to develop bacterial vaccines that prevent severe post-influenza bacterial pneumonia. Here, an improved Yersinia pseudotuberculosis strain (designated as YptbS46) possessing an Asd+ plasmid pSMV92 could synthesize high amounts of the Spn pneumococcal surface protein A (PspA) antigen and monophosphoryl lipid A as an adjuvant. The recombinant strain produced outer membrane vesicles (OMVs) enclosing a high amount of PspA protein (designated as OMV-PspA). A prime-boost intramuscular immunization with OMV-PspA induced both memory adaptive and innate immune responses in vaccinated mice, reduced the viral and bacterial burden, and provided complete protection against influenza-mediated secondary Spn infection. Also, the OMV-PspA immunization afforded significant cross-protection against the secondary Spn A66.1 infection and long-term protection against the secondary Spn D39 challenge. Our study implies that an OMV vaccine delivering Spn antigens can be a new promising pneumococcal vaccine candidate.

Pneumonic Plague Protection Induced by a Monophosphoryl Lipid A Decorated Yersinia Outer-Membrane-Vesicle Vaccine

A new Yersinia pseudotuberculosis mutant strain, YptbS46, carrying the lpxE insertion and pmrF-J deletion is constructed and shown to exclusively produce monophosphoryl lipid A (MPLA) having adjuvant properties. Outer membrane vesicles (OMVs) isolated from YptbS46 harboring an lcrV expression plasmid, pSMV13, are designated OMV46-LcrV, which contained MPLA and high amounts of LcrV (Low Calcium response V) and displayed low activation of Toll-like receptor 4 (TLR4). Intramuscular prime-boost immunization with 30 µg of of OMV46-LcrV exhibited substantially reduced reactogenicity than the parent OMV44-LcrV and conferred complete protection to mice against a high-dose of respiratory Y. pestis challenge. OMV46-LcrV immunization induced robust adaptive responses in both lung mucosal and systemic compartments and orchestrated innate immunity in the lung, which are correlated with rapid bacterial clearance and unremarkable lung damage during Y. pestis challenge. Additionally, OMV46-LcrV immunization conferred long-term protection. Moreover, immunization with reduced doses of OMV46-LcrV exhibited further lower reactogenicity and still provided great protection against pneumonic plague. The studies strongly demonstrate the feasibility of OMV46-LcrV as a new type of plague vaccine candidate.

Pneumonic plague protection induced by a monophosphoryl lipid A decorated Yersinia outer-membrane-vesicle vaccine

A newly constructed Yersinia pseudotuberculosis mutant (YptbS46) carrying the lpxE insertion and pmrF-J deletion exclusively synthesized an adjuvant form of lipid A, monophosphoryl lipid A (MPLA). Outer membrane vesicles (OMVs) isolated from YptbS46 harboring an lcrV expression plasmid, pSMV13, were designated OMV 46 -LcrV, which contained MPLA and high amounts of LcrV and displayed low activation of Toll-like receptor 4 (TLR4). Similar to the previous OMV 44 -LcrV, intramuscular prime-boost immunization with 30 µg of OMV 46 -LcrV exhibited substantially reduced reactogenicity and conferred complete protection to mice against a high-dose of respiratory Y. pestis challenge. OMV 46 -LcrV immunization induced robust adaptive responses in both lung mucosal and systemic compartments and orchestrated innate immunity in the lung, which were correlated with rapid bacterial clearance and unremarkable lung damage during Y. pestis challenge. Additionally, OMV 46 -LcrV immunization conferred long-term protection. Moreover, immunization with reduced doses of OMV 46 -LcrV exhibited further lower reactogenicity and still provided great protection against pneumonic plague. Our studies strongly demonstrate the feasibility of OMV 46 -LcrV as a new type of plague vaccine candidate.

Sugar, sugar: Glucose activates motion in pancreatic cilia

Pancreatic primary cilia are active and dynamic, not static antenna-like sensors as previously thought. This movement may be an important mechanism to glucose regulation.

The effects of aerobic exercise on the intestinal tumors and flora of the ApcMin/+ mouse

INTRODUCTION

Intestinal tumor is one of the most common tumors that seriously threaten the health of residents all over the world. Studies suggest that the imbalance of intestinal flora is associated with tumorgenesis; meanwhile, long-term regular aerobic exercise can improve the occurrence and development of tumors. However, moderate aerobic exercise affecting the development of intestinal tumors and their related flora has not been explored. Thus, the purpose of our study is to explore the effects of aerobic exercise on intestinal tumor growth and flora changes in Apc^Min/+ mice, and try to answer whether there is a correlation between them after exercise intervention.

METHODS

In this study, 18 required Apc^Min/+ mice were randomly divided into Model group (n = 6), Exercise group (n = 6), and Aspirin group (positive control, n = 6), while C57BL/6 J wild-type mice were used as the blank control group. Each group is given corresponding intervention. Weight monitoring, tumor counts, hematoxylin-eosin staining, TdT-mediated dUTP nick-end labeling (TUNEL) fluorescence assay, immunohistochemistry (IHC), fecal sampling and grouping, and bacterial 16S rDNA gene analysis were completed after 12 weeks' intervention for each group of mice.

RESULTS

As a result, we were able to show significant improvements in mice' body weight changing rates (Exercise group 8.6% higher than Model control group), tumor numbers (Exercise group 4.33 ± 0.94 vs. Model control group 7.33 ± 2.49, Then put the slides into xylenewith tumor inhibition rate 40.93%), tumor pathological staging (Exercise group mainly low-grade tumorous adenomas vs. Model group mainly high-grade adenomas), and TUNEL staining (Exercise group 8.59% higher positive rate of apoptotic cells in tumors than Model group). The 16s rRNA sequencing analysis results showed that aerobic exercise could regulate the abundance of some genus (16/149, P < 0.01), and the number of intestinal tumors correlates with changes in the abundance of some bacteria in the intestinal flora (positive correlation with probiotics abundance and negative correlation with conditioned pathogens).

DISCUSSION

Changes in flora abundance may be one of the reasons for aerobic exercise to reduce the number of intestinal tumors, probably mediated by cell apoptosis. Future studies should focus on the potential mechanism of aerobic exercise in preventing intestinal tumorgenesis, especially the molecular mechanism through intestinal flora.

CONCLUSION

Aerobic exercise has a preventive effect on intestinal tumors in Apc^Min/+ mice, and can regulate the abundance of intestinal flora.

A common partitivirus infection in United States and Czech Republic isolates of bat white-nose syndrome fungal pathogen Pseudogymnoascus destructans

The psychrophilic (cold-loving) fungus Pseudogymnoascus destructans was discovered more than a decade ago to be the pathogen responsible for white-nose syndrome, an emerging disease of North American bats causing unprecedented population declines. The same species of fungus is found in Europe but without associated mortality in bats. We found P. destructans was infected with a mycovirus [named Pseudogymnoascus destructans partitivirus 1 (PdPV-1)]. The virus is bipartite, containing two double-stranded RNA (dsRNA) segments designated as dsRNA1 and dsRNA2. The cDNA sequences revealed that dsRNA1 dsRNA is 1,683 bp in length with an open reading frame (ORF) that encodes 539 amino acids (molecular mass of 62.7 kDa); dsRNA2 dsRNA is 1,524 bp in length with an ORF that encodes 434 amino acids (molecular mass of 46.9 kDa). The dsRNA1 ORF contains motifs representative of RNA-dependent RNA polymerase (RdRp), whereas the dsRNA2 ORF sequence showed homology with the putative capsid proteins (CPs) of mycoviruses. Phylogenetic analyses with PdPV-1 RdRp and CP sequences indicated that both segments constitute the genome of a novel virus in the family Partitiviridae. The purified virions were isometric with an estimated diameter of 33 nm. Reverse transcription PCR (RT-PCR) and sequencing revealed that all US isolates and a subset of Czech Republic isolates of P. destructans were infected with PdPV-1. However, PdPV-1 appears to be not widely dispersed in the fungal genus Pseudogymnoascus, as non-pathogenic fungi P. appendiculatus (1 isolate) and P. roseus (6 isolates) tested negative. P. destructans PdPV-1 could be a valuable tool to investigate fungal biogeography and the host-pathogen interactions in bat WNS.

High-resolution characterization of centriole distal appendage morphology and dynamics by correlative STORM and electron microscopy

Centrioles are vital cellular structures that form centrosomes and cilia. The formation and function of cilia depends on a set of centriole's distal appendages. In this study, we use correlative super resolution and electron microscopy to precisely determine where distal appendage proteins localize in relation to the centriole microtubules and appendage electron densities. Here we characterize a novel distal appendage protein ANKRD26 and detail, in high resolution, the initial steps of distal appendage assembly. We further show that distal appendages undergo a dramatic ultra-structural reorganization before mitosis, during which they temporarily lose outer components, while inner components maintain a nine-fold organization. Finally, using electron tomography we reveal that mammalian distal appendages associate with two centriole microtubule triplets via an elaborate filamentous base and that they appear as almost radial finger-like protrusions. Our findings challenge the traditional portrayal of mammalian distal appendage as a pinwheel-like structure that is maintained throughout mitosis.

AbmR (Rv1265) is a novel transcription factor of Mycobacterium tuberculosis that regulates host cell association and expression of the non-coding small RNA Mcr11

Gene regulatory networks used by Mycobacterium tuberculosis (Mtb) during infection include many genes of unknown function, confounding efforts to determine their roles in Mtb biology. Rv1265 encodes a conserved hypothetical protein that is expressed during infection and in response to elevated levels of cyclic AMP. Here, we report that Rv1265 is a novel auto‐inhibitory ATP‐binding transcription factor that upregulates expression of the small non‐coding RNA Mcr11, and propose that Rv1265 be named ATP‐binding mcr11regulator (AbmR). AbmR directly and specifically bound DNA, as determined by electrophoretic mobility shift assays, and this DNA‐binding activity was enhanced by AbmR’s interaction with ATP. Genetic knockout of abmR in Mtb increased abmR promoter activity and eliminated growth phase‐dependent increases in mcr11 expression during hypoxia. Mutagenesis identified arginine residues in the carboxy terminus that are critical for AbmR’s DNA‐binding activity and gene regulatory function. Limited similarity to other DNA‐ or ATP‐binding domains suggests that AbmR belongs to a novel class of DNA‐ and ATP‐binding proteins. AbmR was also found to form large organized structures in solution and facilitate the serum‐dependent association of Mtb with human lung epithelial cells. These results indicate a potentially complex role for AbmR in Mtb biology.

The Developmental Process of the Growing Motile Ciliary Tip Region

Eukaryotic motile cilia/flagella play vital roles in various physiological processes in mammals and some protists. Defects in cilia formation underlie multiple human disorders, known as ciliopathies. The detailed processes of cilia growth and development are still far from clear despite extensive studies. In this study, we characterized the process of cilium formation (ciliogenesis) by investigating the newly developed motile cilia of deciliated protists using complementary techniques in electron microscopy and image analysis. Our results demonstrated that the distal tip region of motile cilia exhibit progressive morphological changes as cilia develop. This developmental process is time-dependent and continues after growing cilia reach their full lengths. The structural analysis of growing ciliary tips revealed that B-tubules of axonemal microtubule doublets terminate far away from the tip end, which is led by the flagellar tip complex (FTC), demonstrating that the FTC might not directly mediate the fast turnover of intraflagellar transport (IFT).

Accurate analysis of fusion expression of Pichia pastoris glycosylphosphatidylinositol-modified cell wall proteins

Glycosylphosphatidylinositol (GPI)-anchored glycoproteins have diverse intrinsic functions in yeasts, and they also have different uses in vitro. The GPI-modified cell wall proteins GCW21, GCW51, and GCW61 of Pichia pastoris were chosen as anchoring proteins to construct co-expression strains in P. pastoris GS115. The hydrolytic activity and the amount of Candida antarctica lipase B (CALB) displayed on cell surface increased significantly following optimization of the fusion gene dosage and combination of the homogeneous or heterogeneous cell wall proteins. Maximum CALB hydrolytic activity was achieved at 4920 U/g dry cell weight in strain GS115/CALB-GCW (51 + 51 + 61 + 61) after 120 h of methanol induction. Changes in structural morphology and the properties of the cell surfaces caused by co-expression of fusion proteins were observed by transmission electron microscopy (TEM) and on plates containing cell-wall-destabilizing reagent. Our results suggested that both the outer and inner cell layers were significantly altered by overexpression of GPI-modified cell wall proteins. Interestingly, quantitative analysis of the inner layer components showed an increase in β-1,3-glucan, but no obvious changes in chitin in the strains overexpressing GPI-modified cell wall proteins.

Cryo-FIB specimen preparation for use in a cartridge-type cryo-TEM

Cryo-electron tomography (cryo-ET) is a well-established technique for studying 3D structural details of subcellular macromolecular complexes and organelles in their nearly native context in the cell. A primary limitation of the application of cryo-ET is the accessible specimen thickness, which is less than the diameters of almost all eukaryotic cells. It has been shown that focused ion beam (FIB) milling can be used to prepare thin, distortion-free lamellae of frozen biological material for high-resolution cryo-ET. Commercial cryosystems are available for cryo-FIB specimen preparation, however re-engineering and additional fixtures are often essential for reliable results with a particular cryo-FIB and cryo-transmission electron microscope (cryo-TEM). Here, we describe our optimized protocol and modified instrumentation for cryo-FIB milling to produce thin lamellae and subsequent damage-free cryotransfer of the lamellae into our cartridge-type cryo-TEM.

Resveratrol improves delayed r-tPA treatment outcome by reducing MMPs

OBJECTIVES

Although recombinant tissue plasminogen activator (r-tPA) is currently the most effective treatment for brain ischemic stroke, the 3-h narrow therapeutic windows severely limits its clinical efficacy. We aim to investigate the effect of resveratrol on improving treatment outcomes of delayed r-tPA administration.

MATERIALS & METHODS

Patients were randomly divided according to their onset-to-treatment time (OTT), as early OTT or delayed OTT. Then, they were either treated with r-tPA + placebo or with r-tPA + resveratrol. Twenty-four hours after the treatment, outcomes were assessed with NIH stroke scale (NIHSS), and plasma levels of MMP-2 and MMP-9 were also examined with ELISA.

RESULTS

In patients receiving delayed r-tPA treatment, co-administration of resveratrol significantly improves their treatment outcomes compared with those receiving placebo, as indicated by improved NIHSS scores. This improved outcome was be caused by resveratrol-induced reduction in plasma levels of both matrix metalloproteinase (MMP)-2 and MMP-9, as a positive correlation was observed between reductions in both MMPs and patient NIHSS scores.

CONCLUSIONS

Resveratrol could be potentially administered as an adjuvant with r-tPA treatment, which extends the clinical therapeutic window of r-tPA, therefore improving the outcome of patients receiving late stroke treatment.

Unattached kinetochores rather than intrakinetochore tension arrest mitosis in taxol-treated cells

Taxol induces extensive structural reorganization of the mammalian kinetochore; however, this reorganization is not sufficient to maintain a long-term mitotic arrest unless some of the kinetochores completely lose their attachment to microtubules.

Kinetochores attach chromosomes to the spindle microtubules and signal the spindle assembly checkpoint to delay mitotic exit until all chromosomes are attached. Light microscopy approaches aimed to indirectly determine distances between various proteins within the kinetochore (termed Delta) suggest that kinetochores become stretched by spindle forces and compact elastically when the force is suppressed. Low Delta is believed to arrest mitotic progression in taxol-treated cells. However, the structural basis of Delta remains unknown. By integrating same-kinetochore light microscopy and electron microscopy, we demonstrate that the value of Delta is affected by the variability in the shape and size of outer kinetochore domains. The outer kinetochore compacts when spindle forces are maximal during metaphase. When the forces are weakened by taxol treatment, the outer kinetochore expands radially and some kinetochores completely lose microtubule attachment, a condition known to arrest mitotic progression. These observations offer an alternative interpretation of intrakinetochore tension and question whether Delta plays a direct role in the control of mitotic progression.

Glabridin nanosuspension for enhanced skin penetration: formulation optimization, in vitro and in vivo evaluation

Glabridin, a polyphenolic flavonoid from licorice, has inspired great interest for its antioxidant, anti-inflammatory and skin-lightening activities. However, low water solubility and poor stability of glabridin impedes its topical application in cosmetic products and therapies of dermal diseases. The purpose of this study was to develop a nanosuspension formulation of glabridin to improve its skin permeation. Glabridin nanosuspensions were prepared using anti-solvent precipitation-homogenization method, and Box-Behnken design was adopted to investigate the effects of crucial formulation variables on particle size and to optimize the nanosuspension formulation. The optimal formulation consisted of 0.25% glabridin, 0.47% Poloxamer 188 and 0.11% Polyvinylpyrrolidone K30, and the obtained nanosuspension showed an average particle size of 149.2 nm with a polydispersity index of 0.254. Furthermore, the nanosuspension exhibited significantly enhanced drug permeation flux of glabridin through rat skin with no lag phase both in vitro and in vivo, compared to the coarse suspension and physical mixture. The glabridin nanosuspension showed no significant particle aggregates and a drug loss of 5.46% after storage for 3 months at room temperature. With its enhanced skin penetration, the nanosuspension might be a more preferable formulation for topical administration of poorly soluble glabridin.

Effect of embolic microspheres in the treatment of primary hepatic carcinoma

The purpose of this study was to evaluate the clinical effect of embolic microspheres in the treatment of primary hepatic carcinoma. Fifty-eight patients who were confirmed with primary hepatic carcinoma by imaging were retrospectively analyzed. They were firstly perfused with 50 mg of oxaliplatin and 40 mg of epirubicin. Embolic microspheres were then injected into the distal end of targeted blood vessels. After this procedure, dynamic observation was carried out until tumor stain disappeared. Liver function and blood indexes were reexamined on days 5, 6, 7 and 28 after treatment, and moreover, the liver was examined with Magnetic Resonance Imaging (MRI) or computed tomography (CT). Compared to traditional lipiodol embolization, embolic microspheres did not aggregate the damage on liver function and the imaging examination suggested necrosis of some tumor tissues. Embolic microspheres proved to be effective in treating primary hepatic carcinoma. It produces no damage on liver function and can lead to significant shrinkage of hepatic carcinoma and necrosis of some tumor tissues. Embolic microspheres, which merely block distal branches of tumor-feeding artery, can avoid collateral circulation induced by permanent blocking, thus achieve a good treatment effect.

Display of fungal hydrophobin on the Pichia pastoris cell surface and its influence on Candida antarctica lipase B

To modify the Pichia pastoris cell surface, two classes of hydrophobins, SC3 from Schizophyllum commune and HFBI from Trichoderma reesei, were separately displayed on the cell wall. There was an observable increase in the hydrophobicity of recombinant strains. Candida antarctica lipase B (CALB) was then co-displayed on the modified cells, generating strains GS115/SC3-61/CALB-51 and GS115/HFBI-61/CALB-51. Interestingly, the hydrolytic and synthetic activities of strain GS115/HFBI-61/CALB-51 increased by 37 and 109 %, respectively, but decreased by 26 and 43 %, respectively, in strain GS115/SC3-61/CALB-51 compared with the hydrophobin-minus recombinant strain GS115/CALB-GCW51. The amount of glycerol by-product from the transesterification reaction adsorbed on the cell surface was significantly decreased following hydrophobin modification, removing the glycerol barrier and allowing substrates to access the active sites of lipases. Electron micrographs indicated that the cell wall structures of both recombinant strains appeared altered, including changes to the inner glucan layer and outer mannan layer. These results suggest that the display of hydrophobins can change the surface structure and hydrophobic properties of P. pastoris and affect the catalytic activities of CALB displayed on the surface of P. pastoris cells.

Effect of fringe-artifact correction on sub-tomogram averaging from Zernike phase-plate cryo-TEM

Zernike phase-plate (ZPP) imaging greatly increases contrast in cryo-electron microscopy, however fringe artifacts appear in the images. A computational de-fringing method has been proposed, but it has not been widely employed, perhaps because the importance of de-fringing has not been clearly demonstrated. For testing purposes, we employed Zernike phase-plate imaging in a cryo-electron tomographic study of radial-spoke complexes attached to microtubule doublets. We found that the contrast enhancement by ZPP imaging made nonlinear denoising insensitive to the filtering parameters, such that simple low-frequency band-pass filtering made the same improvement in map quality. We employed sub-tomogram averaging, which compensates for the effect of the "missing wedge" and considerably improves map quality. We found that fringes (caused by the abrupt cut-on of the central hole in the phase plate) can lead to incorrect representation of a structure that is well-known from the literature. The expected structure was restored by amplitude scaling, as proposed in the literature. Our results show that de-fringing is an important part of image-processing for cryo-electron tomography of macromolecular complexes with ZPP imaging.

Inside out: tubulin cytomotive filaments versus microtubules

In this issue of Structure, Zehr and colleagues describe a structure of a three-stranded PhuZ tubulin cytomotive filament determined at 8.6 Å resolution. This reveals an assembly mechanism different from that of microtubules, leading to a hypothesis explaining cytomotive-filament dynamics.

Direct kinetochore-spindle pole connections are not required for chromosome segregation

In the absence of continuous K-fiber attachment between each kinetochore and the spindle pole, one or more additional mechanisms dependent on dynein-mediated kinetochore transport exist to ensure proper chromosome segregation during mitosis.

Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes′ kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells.

12S-hydroxyeicosatetraenoic acid levels link to coronary artery disease in Type 2 diabetic patients

BACKGROUND

12(S)-Hydroxyeicosatetraenoic acid (12(S)-HETE) is a metabolite of arachidonic acid. 12(S)-HETE is involved in the pathogenesis of atherosclerosis and diabetes. However, the correlation between 12(S)-HETE and coronary artery disease (CAD) in the diabetic patient is unclear.

AIMS

The study investigated the relationship between 12(S)-HETE and CAD in Type 2 diabetes (T2D).

METHODS

Plasma 12(S)- HETE levels were detected by enzyme-linked immunosorbent assay in 103 healthy controls (control), 109 diabetic patients without CAD (diabetic), and 152 diabetic patients with CAD (diabetic-CAD).

RESULTS

12(S)-HETE levels were higher in both diabetic and diabetic-CAD groups compared to control and in the diabetic-CAD group compared to the diabetic group. In the multiple linear stepwise regression analysis, 12(S)-HETE levels correlated independently with CAD, systolic blood pressure, and glycated hemoglobin.

CONCLUSIONS

These results indicate that 12(S)-HETE levels are increased in diabetic patients with CAD, suggesting a role for atherosclerosis in T2D.

Ferret lung transplant: an orthotopic model of obliterative bronchiolitis

Obliterative bronchiolitis (OB) is the primary cause of late morbidity and mortality following lung transplantation. Current animal models do not reliably develop OB pathology. Given the similarities between ferret and human lung biology, we hypothesized an orthotopic ferret lung allograft would develop OB. Orthotopic left lower lobe transplants were successfully performed in 22 outbred domestic ferrets in the absence of immunosuppression (IS; n = 5) and presence of varying IS protocols (n = 17). CT scans were performed to evaluate the allografts. At intervals between 3-6 months the allografts were examined histologically for evidence of acute/chronic rejection. IS protects allografts from acute rejection and early graft loss. Reduction of IS dosage by 50% allowed development of controlled rejection. Allografts developed infiltrates on CT and classic histologic acute rejection and lymphocytic bronchiolitis. Cycling of IS, to induce repeated episodes of controlled rejection, promoted classic histologic hallmarks of OB including fibrosis-associated occlusion of the bronchiolar airways in all allografts of long-term survivors. In conclusion, we have developed an orthotopic lung transplant model in the ferret with documented long-term functional allograft survival. Allografts develop acute rejection and lymphocytic bronchiolitis, similar to humans. Long-term survivors develop histologic changes in the allografts that are hallmarks of OB.

Signal transduction pathways and transcriptional mechanisms of ABCB1/Pgp-mediated multiple drug resistance in human cancer cells

Multiple drug resistance (MDR), defined as the ability of tumour cells to survive exposure to many chemotherapeutic agents, is a major cause of treatment failure in human cancers. The membrane transporter P-glycoprotein (Pgp, encoded by the ABCB1 [adenosine triphosphate-binding cassette, subfamily B, member 1] gene) is the main mechanism for decreased intracellular drug accumulation in human MDR cancer. ABCB1/Pgp-mediated MDR involves several signal transduction pathways and transcription factors. Activation of these signal transduction pathways influences the prognosis of MDR human cancer. Signalling pathways involved in ABCB1/Pgp-mediated MDR include the mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase (JNK), p38, cyclic adenosine monophosphate-dependent protein kinase, phosphatidylino sitol 3-kinase and protein kinase C signalling pathways. This review summarizes the biological characteristics, target points and signalling cascade mediators of these pathways. Drugs targeted against these pathways may provide new therapies for treatment of ABCB1/Pgp-mediated MDR.

The effects of the Chinese medicine ZiBu PiYin recipe on the hippocampus in a rat model of diabetes-associated cognitive decline: a proteomic analysis

AIMS/HYPOTHESIS

Increasing evidence suggests that diabetes is associated with an enhanced risk of cognitive decline. The precise mechanisms underlying diabetes-associated cognitive decline (DACD) remain unclear. Here we investigated the molecular changes associated with DACD using a comparative proteomics study of hippocampus in a rat model of type 2 diabetes. In addition, we tested the effects of the Chinese medicine ZiBu PiYin recipe (ZBPYR) on DACD.

METHODS

The hippocampus was dissected from control, diabetic and diabetic rats treated with ZBPYR (DM/ZBPYR). Soluble proteins were separated using fluorescence-based difference gel electrophoresis. Protein spots were visualised with fluorescent dyes and spot density was compared between each pair of groups. Proteins of interest were identified using mass spectrometry. Proteins of specific interest were also tested by western blot and real-time PCR analysis.

RESULTS

We found 13 spots that were altered between control and diabetes groups, and 12 spots that were changed between diabetes and DM/ZBPYR groups. The identities of nine proteins were determined by mass spectrometry. The identified proteins were largely involved in energy metabolism, cytoskeleton regulation and oxidative stress. The protein alterations observed in the diabetes group were ameliorated to varying degrees following ZBPYR treatment.

CONCLUSIONS/INTERPRETATION

The protein changes identified in hippocampus from a rat model of type 2 diabetes suggest that specific cellular alterations contribute to DACD. The Chinese medicine ZBPYR was found to affect multiple targets and partially repaired the original cellular balance. This study may provide important insights into the molecular events underlying DACD and allow the identification of novel therapeutic targets.

Safety assessment of Lactobacillus brevis KB290 as a probiotic strain

Lactobacillus brevis KB290 (KB290), a plant-derived probiotic lactic acid bacterium, reportedly improves gut health and stimulates immune function. Here we extensively investigated the geno-, acute, subacute, and subchronic toxicity of KB290 and its bacterial translocation potential. KB290 was non-mutagenic in the bacterial reverse mutation assay by the preincubation method. In the single oral dose toxicity test, KB290 at 10(9) cfu/ml was nontoxic at maximum capacity (20 ml/kg). When 10(8), 10(9), or 10(10) cfu/kg was administered daily to rats by gavage for 2 weeks (subacute assay), we observed no clear treatment-related effect and no evidence of bacterial translocation from the gastrointestinal tract. When it was administered for 13 weeks (subchronic assay), we again observed no clear treatment-related effect and no significant toxicological effect. Based on those results, we consider 10(10) cfu/kg per day, the highest dose tested, to be the no observed adverse effect level (NOAEL). These results suggest that KB290 is safe for human consumption.

Structural insights into microtubule doublet interactions in axonemes

Coordinated sliding of microtubule doublets, driven by dynein motors, produces periodic beating of eukaryotic cilia and flagella. Recent structural studies of the axoneme, which forms the core of cilia and flagella, have used cryo-electron tomography to reveal new details of the interactions between some of the multitude of proteins that form the axoneme and regulate its movement. Connections between the several types of dyneins, in particular, suggest ways in which their action might be coordinated. Study of the molecular architecture of isolated doublets has provided a structural basis for understanding mechanical properties related to the bending of the axoneme, and has also offered insight into the potential role of doublets in the mechanism of dynein activity regulation.

Molecular architecture of axonemal microtubule doublets revealed by cryo-electron tomography

The axoneme, which forms the core of eukaryotic flagella and cilia, is one of the largest macromolecular machines, with a structure that is largely conserved from protists to mammals. Microtubule doublets are structural components of axonemes that contain a number of proteins besides tubulin, and are usually found in arrays of nine doublets arranged around two singlet microtubules. Coordinated sliding of adjacent doublets, which involves a host of other proteins in the axoneme, produces periodic beating movements of the axoneme. We have obtained a three-dimensional density map of intact microtubule doublets using cryo-electron tomography and image averaging. Our map, with a resolution of about 3 nm, provides insights into locations of particular proteins within the doublets and the structural features of the doublets that define their mechanical properties. We identify likely candidates for several of these non-tubulin components of the doublets. This work offers insight on how tubulin protofilaments and accessory proteins attach together to form the doublets and provides a structural basis for understanding doublet function in axonemes.

Crystal structure of human calmodulin-like protein: insights into its functional role

A calmodulin (CaM)-like protein (hCLP) is expressed in human mammary epithelial cells but appears to be limited to certain epithelial cells such as those found in skin, prostate, breast and cervical tissues. A decrease in the expression of this protein is associated with the occurrence of tumors in breast epithelium. The structure of hCLP determined to 1.5 A resolution by X-ray crystallography shows a distinct 30 degrees displacement along the interconnecting central helix, when compared to the highly conserved structure of vertebrate CaM, resulting in a difference in the relative orientation of its two globular domains. Additionally, the electric surface potential landscape at the target protein binding regions on the two globular domains of hCLP is significantly different from those of CaM, indicating that the respective ranges of hCLP and hCaM target proteins do not fully overlap. Observations that hCLP can competitively inhibit CaM activation of target proteins also imply a role for hCLP in which it may also serve as a modulator of CaM activity in the epithelial cells where hCLP is expressed.

Structural basis of water-specific transport through the AQP1 water channel

Water channels facilitate the rapid transport of water across cell membranes in response to osmotic gradients. These channels are believed to be involved in many physiological processes that include renal water conservation, neuro-homeostasis, digestion, regulation of body temperature and reproduction. Members of the water channel superfamily have been found in a range of cell types from bacteria to human. In mammals, there are currently 10 families of water channels, referred to as aquaporins (AQP): AQP0-AQP9. Here we report the structure of the aquaporin 1 (AQP1) water channel to 2.2 A resolution. The channel consists of three topological elements, an extracellular and a cytoplasmic vestibule connected by an extended narrow pore or selectivity filter. Within the selectivity filter, four bound waters are localized along three hydrophilic nodes, which punctuate an otherwise extremely hydrophobic pore segment. This unusual combination of a long hydrophobic pore and a minimal number of solute binding sites facilitates rapid water transport. Residues of the constriction region, in particular histidine 182, which is conserved among all known water-specific channels, are critical in establishing water specificity. Our analysis of the AQP1 pore also indicates that the transport of protons through this channel is highly energetically unfavourable.

Crystallization and preliminary X-ray crystallographic analysis of water channel AQP1

Aquaporin-1 (AQP1), a water channel from bovine red blood cells has been deglycosylated, purified to homogeneity and crystallized in a form suitable for X-ray crystallographic study. Crystals are grown using polyethylene glycol as precipitant and belong to the tetragonal space group I422, with unit-cell parameters a = b = 93.4, c = 180.4 A. The crystals diffract beyond 2.2 A resolution.

Mutation induction by N-propyl-N-nitrosourea in eight MutaMouse organs

As a part of the 2nd Collaborative Study for the Transgenic Mouse Mutation Assay, we studied the organ specificity and the temporal changes in mutant frequency (MF) of the lacZ gene following intraperitoneal injection of 250 mg/kg N-propyl-N-nitrosourea into male MutaMouse. We used a positive selection system and examined eight organs, i.e., bone marrow, liver, kidney, lung, spleen, brain, heart, and testis. The chemical caused a significant increase in MF in all organs except for brain, and the bone marrow was the most sensitive organ, exhibiting a MF on day 7 that was 10 times that of the control. The MF increased from day 7 to day 28 in liver, kidney, and testis, while it decreased in bone marrow. The relationship between the results of this study and the target organs of carcinogenesis, and the cause of the temporal changes in MF, are discussed.

Partial hepatectomy strongly increased the mutagenicity of N-ethyl-N-nitrosourea in MutaMouse liver

The relationship between cell proliferation and mutagenesis can be investigated in vivo due to the advent of transgenic animal mutation assays. In these assays, slowly proliferating tissues, such as mammary gland and liver, that are exposed to mutagens generally have longer manifestation times for mutations and lower mutant frequencies. This may be because the cells have enough time prior to cell division to repair DNA damage. We carried out this study using the MutaMouse positive selection system to investigate the effect of a high rate of cell proliferation induced by partial hepatectomy (PH) on mutation induction. We used a 2 x 2 experimental design for PH (or no PH) and 50 mg/kg N-ethyl-N-nitrosourea (ENU) (or phosphate buffer), with the chemical injected 16-19 hr after PH. In the non-ENU groups, the mean MF was slightly but not significantly higher in the PH group than in the non-PH group. In the ENU non-PH group, the MF was also slightly but not significantly increased. In the ENU PH group, in contrast, the mean MF was 7 times the mean MF of the group that received either treatment alone. These results strongly support the hypothesis that ENU induced pre-mutational DNA lesions in liver are completely repaired prior to cell division, and PH increases the mutagen-induced MF by reducing the amount of time available for such repair.

Effects of O (6)-alkylguanine-DNA alkyltransferase deficiency in Escherichia coli as the host for the detection of mutations in lacI transgenic mice

Transgenic mice are widely used to detect gene mutations in vivo induced by a variety of chemicals. It is known, however, that no mutagenicity of methyl methanesulfonate (MMS) is detected in epididymal sperm in various transgenic mice assays, although MMS induces the dominant lethal and specific locus mutations in male mice. To investigate the issue of whether unrepaired lesions in DNA of mature sperm can be transformed into mutations during replication of the lambda phage in Escherichia coli cells, we developed an E. coli strain YG5152, which is a derivative of strain SCS-8 but is deficient in the genes encoding O (6)-alkylguanine-DNA alkyltransferases. When lambda LIZalpha phages were treated with MMS or N-ethyl-N-nitrosourea (ENU) in vitro and infected to the E. coli strains, the mutant frequencies of lacI were markedly higher in strain YG5152 than in strain SCS-8. When Big Blue(trade mark) mice were treated with MMS (160 mg/kg) or ENU (125 or 250 mg/kg) and the phages rescued from mature sperm were infected to the strains, the mutation frequency (MF) of phages from ENU-treated mice at a dose of 250 mg/kg in strain YG5152 was about two times higher than that in strain SCS-8. However, no increase in the MF was observed in the MMS-treated mice even in strain YG5152. These results suggest that, although strain YG5152 efficiently detects ex vivo mutations caused by mutagenic alkyl adducts formed by MMS in lambda phage DNA, no detectable levels of mutagenic methyl adducts are present in mature sperm of MMS-treated mice. Possible reasons for this lack of mutagenicity of MMS in mature sperm using transgenic mice assays are discussed.

Epigenetic reprogramming of the human H19 gene in mouse embryonic cells does not erase the primary parental imprint

BACKGROUND

Genomic imprinting in mammals is thought to result from epigenetic modifications to chromosomes during gametogenesis, which leads to differential allelic expression during development. There is a requirement for an appropriate experimental system to enable the analysis of the mechanisms of genomic imprinting during embryogenesis.

RESULTS

To develop a novel in vitro system for studying the molecular basis of genomic imprinting, we constructed mouse cell lines containing either a paternal or maternal human chromosome 11, by microcell-mediated chromosome transfer. Allele-specific expression and DNA methylation studies revealed that the imprinting status of the human H19 gene was maintained in mouse A9 mono-chromosomal hybrids. Each parental human chromosome was introduced independently into mouse near-diploid immortal fibroblasts (m5S) and two embryonal carcinoma (EC) cell lines (OTF9-63 and P19). The paternal allele of human H19 remained in a repressed state in m5S cells, but was de-repressed in both EC cells. The paternal H19 allele was demethylated extensively in OTF9-63 cells, whereas the only alteration in P19 hybrids was de novo methylation on both alleles in the 3' region. Following in vitro differentiation, the expressed paternal H19 allele was selectively repressed in differentiated derivatives of EC hybrids.

CONCLUSION

These results indicated that human imprint marks could function effectively in mouse cells, and that the imprinting process was epigenetically reprogrammed in embryonal carcinoma cells, without erasure of the primary imprint that marked the parental origin. Therefore, these mono-chromosomal hybrids could provide a valuable in vitro system to study the mechanisms involved in the regulation of imprinted gene expression.

[Primary microsurgical repair of multi-structural defects of hand]

Forty-eight cases of multi-structural defects of hands were primarily repaired or reconstructed from July 1989 to 1997. The structural defects included: the defects of radial or ulnar aspect of hands involving fingers and skin, multiple fingers defects and the fingers and skin defects of whole hand. In this series, there were 32 males and 16 females with age ranged from 17 to 46 years old. The composite tissue grafts were obtained from wrap-around flap or 2nd toe skin flap of the foot. The result showed that composite 108 tissues transplantations, or 48 cases, were all survived. After a follow-up of 38.5 months (ranged from 5 months to 6 years), the grasp, pinch and opposition function of the reconstructed finger were restored, the two-point discrimination sensation was 4 mm-12 mm. Most of the patients had resumed their original works. So that the primary repair of multi-structural defects of hands by composite tissues transplantation was feasible and valuable, but thorough debridement and skilled microsurgecal technique were required.

[The clinical application of bridge by "Y" type vein]

In order to solve the defect of blood vessel in tissue transplantation and complicated palmar amputation, bridge by "Y" type vein had been used from Jan. 1990 to Jul. 1996. Twenty-three cases were treated. In this series, there were 16 males and 7 females, with ages ranged from 10 to 42 years old. Six cases were the defect of lower legs anterior skin and tibia, 3 cases were the femur fracture with injury of femoral artery and tissue's defect, 2 cases were defect of five fingers, 12 cases were complicated palmar amputation.

RESULT

15 cases with tissue transplantation and 12 cases with limb replantation were all survival without infection or necrosis. After the following-up for 3 years (ranged from 1 to 5 years), the function of injured limbs were satisfactory, 19 patients had resumed their original work. So, to bridge by "Y" type vein is a good method for repairing the defect of blood vessels in tissue transplantation and complicated palmar amputation, but skilled microsurgery technique is required.

Paternal expression of WT1 in human fibroblasts and lymphocytes

The Wilms' tumor suppressor gene ( WT1 ) was previously identified as being imprinted, with frequent maternal expression in human placentae and fetal brains. We examined the allele-specific expression of WT1 in cultured human fibroblasts from 15 individuals. Seven of 15 fibroblast lines were heterozygous for polymorphic alleles, and the expression patterns were variable, i.e., equal, unequal or monoallelic paternal expression in three, two and two cases, respectively. Exclusive paternal expression of WT1 was also shown in non-cultured peripheral lymphocytes from the latter two individuals. The allele-specific expression profiles of other imprinted genes, IGF2 and H19, on human chromosome 11 were constant and consistent with those in other tissues. Our unexpected observations of paternal or biallelic expression of WT1 in fibroblasts and lymphocytes, together with the previous findings of maternal or biallelic expression in placentae and brains, suggest that the allele-specific regulatory system of WT1 is unique and may be controlled by a putative tissue- and individual-specific modifier.

Evidence for uniparental, paternal expression of the human GABAA receptor subunit genes, using microcell-mediated chromosome transfer

We have constructed mouse A9 hybrids containing a single normal human chromosome 15, via microcell-mediated chromosome transfer. Cytogenetic and DNA-polymorphic analyses identified mouse A9 hybrids that contained either a paternal or maternal human chromosome 15. Paternal specific expression of the known imprinted genes SNRPN (small nuclear ribonucleoprotein-associated polypeptide N gene) and IPW (imprinted gene in the Prader-Willi syndrome region) was maintained in the A9 hybrids. Using this system, we first demonstrated that human GABAAreceptor subunit genes, GABRB3 , GABRA5 and GABRG3 , were expressed exclusively from the paternal allele and that E6-AP (E6-associated protein or UBE3A ) was biallelically expressed. Moreover, the 5' portion of the GABRB3 gene was found to be hypermethylated on the paternal allele. Our data imply that GABAAreceptor subunit genes are imprinted and are possible candidates for Prader-Willi syndrome, and that this human monochromosomal hybrid system enables the efficient analysis of imprinted loci.

[Inhibition of respiratory syncytial virus (RSV) by moroxydine, allicin, alpha-interferon and their joint application]

This paper reported the inhibition of respiratory syncytial virus by Moroxydine (ABOB), Allicin, alpha-interferon and their joint application. The results indicated that each of the three drugs inhibited RSV in HeLa cells, and the effective dosage of ABOB was 100 mg/L, alpha-interferon 1.5 x 10(4) U/L and Allicin one eight hundred thousandth of the pure material. The combinations of 3 drugs showed synergism without antagonism, this not only decreased the dosage, toxicity but also enhanced the inhibition effects on respiratory syncytial virus obviously.