Autoantibodies against gangliosides GM1 or GD1a are associated with acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN), whereas antibodies to GD1b ganglioside are detected in acute sensory ataxic neuropathy (ASAN). These neuropathies have been proposed to be closely related and comprise a continuous spectrum, although the underlying mechanisms, especially for sensory nerve involvement, are still unclear. Antibodies to GM1 and GD1a have been proposed to disrupt the nodes of Ranvier in motor nerves via complement pathway. We hypothesized that the disruption of nodes of Ranvier is a common mechanism whereby various anti-ganglioside antibodies found in these neuropathies lead to nervous system dysfunction. Here, we show that the IgG monoclonal anti-GD1a/GT1b antibody injected into rat sciatic nerves caused deposition of IgG and complement products on the nodal axolemma and disrupted clusters of nodal and paranodal molecules predominantly in motor nerves, and induced early reversible motor nerve conduction block. Injection of IgG monoclonal anti-GD1b antibody induced nodal disruption predominantly in sensory nerves. In an ASAN rabbit model associated with IgG anti-GD1b antibodies, complement-mediated nodal disruption was observed predominantly in sensory nerves. In an AMAN rabbit model associated with IgG anti-GM1 antibodies, complement attack of nodes was found primarily in motor nerves, but occasionally in sensory nerves as well. Periaxonal macrophages and axonal degeneration were observed in dorsal roots from ASAN rabbits and AMAN rabbits. Thus, nodal disruption may be a common mechanism in immune-mediated neuropathies associated with autoantibodies to gangliosides GM1, GD1a, or GD1b, providing an explanation for the continuous spectrum of AMAN, AMSAN, and ASAN.
doi:10.1016/j.expneurol.2011.11.039
PMCID: PMC3268874
PMID: 22178332
node of Ranvier; acute motor axonal neuropathy; acute sensory ataxic neuropathy; ganglioside; autoantibody
Pan, Wei | Xiao, Jianliang | Zhu, Junwei | Yu, Chenxi | Zhang, Gang | Ni, Zhenhua | Watanabe, K. | Taniguchi, T. | Shi, Yi | Wang, Xinran
Strain engineered graphene has been predicted to show many interesting physics and device applications. Here we study biaxial compressive strain in graphene/hexagonal boron nitride heterostructures after thermal cycling to high temperatures likely due to their thermal expansion coefficient mismatch. The appearance of sub-micron self-supporting bubbles indicates that the strain is spatially inhomogeneous. Finite element modeling suggests that the strain is concentrated on the edges with regular nano-scale wrinkles, which could be a playground for strain engineering in graphene. Raman spectroscopy and mapping is employed to quantitatively probe the magnitude and distribution of strain. From the temperature-dependent shifts of Raman G and 2D peaks, we estimate the TEC of graphene from room temperature to above 1000K for the first time.
doi:10.1038/srep00893
PMCID: PMC3506982
PMID: 23189242
Cui, Zhenling | Wang, Yongzhong | Fang, Liang | Zheng, Ruijuan | Huang, Xiaochen | Liu, Xiaoqin | Zhang, Gang | Rui, Dongmei | Ju, Jinliang | Hu, Zhongyi
The aim of this study was to establish and evaluate a simultaneous amplification and testing method for detection of the Mycobacterium tuberculosis complex (SAT-TB assay) in clinical specimens by using isothermal RNA amplification and real-time fluorescence detection. In the SAT-TB assay, a 170-bp M. tuberculosis 16S rRNA fragment is reverse transcribed to DNA by use of Moloney murine leukemia virus (M-MLV) reverse transcriptase, using specific primers incorporating the T7 promoter sequence, and undergoes successive cycles of amplification using T7 RNA polymerase. Using a real-time PCR instrument, hybridization of an internal 6-carboxyfluorescein–4-[4-(dimethylamino)phenylazo] benzoic acid N-succinimidyl ester (FAM-DABCYL)-labeled fluorescent probe can be used to detect RNA amplification. The SAT-TB assay takes less than 1.5 h to perform, and the sensitivity of the assay for detection of M. tuberculosis H37Rv is 100 CFU/ml. The TB probe has no cross-reactivity with nontuberculous mycobacteria or other common respiratory tract pathogens. For 253 pulmonary tuberculosis (PTB) specimens and 134 non-TB specimens, the SAT-TB results correlated with 95.6% (370/387 specimens) of the Bactec MGIT 960 culture assay results. The sensitivity, specificity, and positive and negative predictive values of the SAT-TB test for the diagnosis of PTB were 67.6%, 100%, 100%, and 62.0%, respectively, compared to 61.7%, 100%, 100%, and 58.0% for Bactec MGIT 960 culture. For PTB diagnosis, the sensitivities of the SAT-TB and Bactec MGIT 960 culture methods were 97.6% and 95.9%, respectively, for smear-positive specimens and 39.2% and 30.2%, respectively, for smear-negative specimens. In conclusion, the SAT-TB assay is a novel, simple test with a high specificity which may enhance the detection rate of TB. It is therefore a promising tool for rapid diagnosis of M. tuberculosis infection in clinical microbiology laboratories.
doi:10.1128/JCM.05853-11
PMCID: PMC3295177
PMID: 22205804
Tian, He | Xie, Dan | Yang, Yi | Ren, Tian-Ling | Zhang, Gang | Wang, Yu-Feng | Zhou, Chang-Jian | Peng, Ping-Gang | Wang, Li-Gang | Liu, Li-Tian
Recently, manipulating heat transport by phononic devices has received significant attention, in which phonon – a heat pulse through lattice, is used to carry energy. In addition to heat control, the thermal devices might also have broad applications in the renewable energy engineering, such as thermoelectric energy harvesting. Elementary phononic devices such as diode, transistor and logic devices have been theoretically proposed. In this work, we experimentally create a macroscopic scale thermal rectifier based on reduced graphene oxide. Obvious thermal rectification ratio up to 1.21 under 12 K temperature bias has been observed. Moreover, this ratio can be enhanced further by increasing the asymmetric ratio. Collectively, our results raise the exciting prospect that the realization of macroscopic phononic device with large-area graphene based materials is technologically feasible, which may open up important applications in thermal circuits and thermal management.
doi:10.1038/srep00523
PMCID: PMC3401993
PMID: 22826801
Background:
Panax notoginseng (PN) is one of the most commonly used Chinese herbal drugs. Panax notoginseng saponins (PNS) is the main effective components of PN. However, the anti-fatigue effect of PNS in plateau-condition is unknown.
Objective:
Explore the anti-fatigue effects of PNS in mice living under simulation plateau-condition.
Materials and Methods:
Hundred male Kunming mice were randomly divided into five groups (n=20): one normoxia control group (NCG), one hypoxia control group (HCG), and three PNS groups in low dosage (0.42 g/kg), mid dosage (1.11 g/kg), and high dosage (11.53 g/kg). HCG and PNS groups were fed at a simulated elevation of 5 km. NCG and HCG were intragastric administrated with distilled water. After continuous administration for 10 days, the exhaustive swimming time, glycogen contents in liver, blood lactic acid (BLA), and blood glucose were determined.
Results:
Exposure of the mice to simulation plateau-condition with 5 km altitude for 10 days caused significant decrease of exercise tolerance compared to normoxia environment. The swimming time and glycogen contents in liver were significantly increased at all tested concentration (0.42, 1.11, and 11.53 g/kg). The area under the BLA curve was significantly decreased at the concentration of 0.42 g/ kg. The blood glucose of resting and 0 minutes after swimming were significantly increased by 29.31% and 15.51% (P<0.05) at a concentration of 11.53 g/kg compared to their own control groups, respectively.
Conclusion:
These results indicate that PNS could postpone the appearance of fatigue and accelerate the restoration of fatigue in plateau environment, especially in low dosage (0.42 g/kg) case.
doi:10.4103/0973-1296.99284
PMCID: PMC3466454
PMID: 23060693
Anti--fatigue; high altitude; Panax notoginseng; plateau
Lentiviral vectors (LVs) are powerful tools for transgene expression in vivo and in vitro. However, the construction of LVs is of low efficiency, due to the large sizes and lack of proper clone sites. Therefore, it is critical to develop efficient strategies for cloning LVs. Here, we reported a combinatorial strategy to efficiently construct LVs using EGFP, hPlk2 wild type (WT) and mutant genes as inserts. Firstly, site-directed mutagenesis (SDM) was performed to create BamH I site for the inserts; secondly, pWPI LV was dephosphorylated after BamH I digestion; finally, the amounts and ratios of the insert and vector DNA were optimized to increase monomeric ligation. Our results showed that the total percentage of positive clones was approximately 48%±7.6%. Using this method, almost all the vectors could be constructed through two or three minipreps. Therefore, our study provided an efficient method for constructing large-size vectors.
doi:10.1038/srep00415
PMCID: PMC3357496
PMID: 22629482
Wang, Jiong | Zhang, Gang | Bambara, Robert A. | Li, Dongge | Liang, Hua | Wu, Hulin | Smith, Hannah M. | Lowe, Nicholas R. | Demeter, Lisa M. | Dykes, Carrie
Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are potent and commonly prescribed antiviral agents used in combination therapy (CART) of human immunodeficiency virus type 1 (HIV-1) infection. The development of drug resistance is a major limitation of CART. Reverse transcriptase (RT) genotypes with the NNRTI resistance mutations K101E+G190S are highly resistant to efavirenz (EFV) and can develop during failure of EFV-containing regimens in patients. We have previously shown that virus with K101E+G190S mutations can replicate more efficiently in the presence of EFV than in its absence. In this study, we evaluated the underlying mechanism for drug-dependent stimulation, using a single-cycle cell culture assay in which EFV was added either during the infection or the virus production step. We determined that EFV stimulates K101E+G190S virus during early infection and does not affect late steps of virus replication, such as increasing the amount of active RT incorporated into virions. Additionally, we showed that another NNRTI, nevirapine (NVP), stimulated K101E+G190S virus replication during the early steps of infection similar to EFV, but that the newest NNRTI, etravirine (ETR), did not. We also showed that EFV stimulates K101E+Y188L and K101E+V106I virus, but not K101E+L100I, K101E+K103N, K101E+Y181C, or K101E+G190A virus, suggesting that the stimulation is mutation specific. Real-time PCR of reverse transcription intermediates showed that although the drug did not stimulate minus-strand transfer, it did stimulate minus-strand strong-stop DNA synthesis. Our results indicate that stimulation most likely occurs through a mechanism whereby NNRTIs stimulate priming or elongation of the tRNA.
doi:10.1128/JVI.05116-11
PMCID: PMC3187512
PMID: 21835788
Background
Genetic variability in the regulation of the nitric oxide (NO) pathway may influence hemodynamic changes in pediatric sepsis. We sought to determine whether functional polymorphisms in DDAH2, which metabolizes the NO synthase inhibitor asymmetric dimethylarginine (ADMA), are associated with susceptibility to sepsis, plasma ADMA, distinct hemodynamic states, and vasopressor requirements in pediatric septic shock.
Methodology/Principal Findings
In a prospective study, blood and buccal swabs were obtained from 82 patients ≤18 years (29 with severe sepsis/septic shock plus 27 febrile and 26 healthy controls). Plasma ADMA was measured using tandem mass spectrometry. DDAH2 gene was partially sequenced to determine the −871 6g/7g insertion/deletion and −449G/C single nucleotide polymorphisms. Shock type (“warm” versus “cold”) was characterized by clinical assessment. The −871 7g allele was more common in septic (17%) then febrile (4%) and healthy (8%) patients, though this was not significant after controlling for sex and race (p = 0.96). ADMA did not differ between −871 6g/7g genotypes. While genotype frequencies also did not vary between groups for the −449G/C SNP (p = 0.75), septic patients with at least one −449G allele had lower ADMA (median, IQR 0.36, 0.30–0.41 µmol/L) than patients with the −449CC genotype (0.55, 0.49–0.64 µmol/L, p = 0.008) and exhibited a higher incidence of “cold” shock (45% versus 0%, p = 0.01). However, after controlling for race, the association with shock type became non-significant (p = 0.32). Neither polymorphism was associated with inotrope score or vasoactive infusion duration.
Conclusions/Significance
The −449G polymorphism in the DDAH2 gene was associated with both low plasma ADMA and an increased likelihood of presenting with “cold” shock in pediatric sepsis, but not with vasopressor requirement. Race, however, was an important confounder. These results support and justify the need for larger studies in racially homogenous populations to further examine whether genotypic differences in NO metabolism contribute to phenotypic variability in sepsis pathophysiology.
doi:10.1371/journal.pone.0033355
PMCID: PMC3299781
PMID: 22428028
A novel strain of H1N1 influenza A virus (pH1N1) emerged in 2009, causing a worldwide pandemic. Several studies suggest that this virus is antigenically more closely related to human influenza viruses that circulated prior to 1957 than viruses of more recent seasonal influenza varieties. The extent to which individuals who are naïve to the 2009 pH1N1 virus carry cross-reactive CD8+ T cells is not known, but a certain degree of reactivity would be expected since there is substantial conservation among the internal proteins of the virus. In the present study, we examined production of multiple cytokines in response to virus from CD8+ T cells in healthy adult subjects, between 18 and 50 years of age (born post 1957), who had no evidence of exposure to the 2009 pH1N1 virus, and had blood collected prior to the emergence of the pandemic in April of 2009. Human peripheral blood mononuclear cells (PBMC) were stimulated in vitro with a panel of live viruses, and assayed by intracellular cytokine staining and flow cytometry. Although results were variable, most subjects exhibited cytokine positive CD8+ T cells in response to pH1N1. Cytokine producing cells were predominantly single positive (IL2, IFNγ, or TNFα); triple-cytokine producing cells were relatively rare. This result suggests that although many adults carry cross-reactive T cells against the emergent pandemic virus, these cells are in a functionally limited state, possibly because these subjects have not had recent exposure to either seasonal or pandemic influenza strains.
doi:10.1016/j.vaccine.2010.12.073
PMCID: PMC3061835
PMID: 21211588
Influenza; heterosubtypic; CD8 T cell; cross-protective immunity; multifunctional
Guillain-Barré syndrome (GBS) is a monophasic immune neuropathic disorder in which a significant proportion of patients have incomplete recovery. The patients with incomplete recovery almost always have some degree of failure of axon regeneration and target reinnervation. Anti-ganglioside antibodies (Abs) are the most commonly recognized autoimmune markers in all forms of GBS and specific Abs are associated with the slow/poor recovery. We recently demonstrated that specific anti-ganglioside Abs inhibit axonal regeneration and nerve repair in preclinical models by activation of small GTPase RhoA and its downstream effectors. The objective of this study was to determine whether erythropoietin (EPO), a pleiotropic cytokine with neuroprotective and neurotrophic properties, enhances nerve regeneration in preclinical cell culture and animal models of autoimmune neuropathy/nerve repair generated with monoclonal and patient derived Abs. Primary neuronal cultures and a standardized sciatic crush nerve model were used to assess the efficacy of EPO in reversing inhibitory effects of anti-ganglioside Abs on nerve repair. We found that EPO completely reversed the inhibitory effects of anti-ganglioside Abs on axon regeneration in cell culture models and significantly improved nerve regeneration/repair in an animal model. Moreover, EPO-induced proregenerative effects in nerve cells are through EPO receptors and Janus kinase 2/Signal transducer and activator of transcription 5 pathway and not via early direct modulation of small GTPase RhoA. These preclinical studies indicate that EPO is a viable candidate drug to develop further for neuroprotection and enhancing nerve repair in patients with GBS.
doi:10.1371/journal.pone.0027067
PMCID: PMC3203932
PMID: 22046448
In the title coordination polymer, {[FeMn(C5H5)(C13H7O4)(C10H9N3)(H2O)]·CH3OH·H2O}n, the MnII ion has a distorted octahedral coordination geometry and is ligated by two N atoms from two di-2-pyridylamine molecules, three O atoms from two 5-ferrocenylbenzene-1,3-dicarboxylate anions and one O atom from a coordinated water molecule. The Mn—O distances range from 2.151 (2) to 2.5093 (19) Å, while the Mn—N distances are 2.226 (2) and 2.248 (2) Å. Each 5-ferrocenylbenzene-1,5-dicarboxylate anion links to two MnII ions, resulting in a chain along the b axis. A three-dimensional network of N—H⋯O and O—H⋯O hydrogen bonds helps to stabilize the crystal packing.
doi:10.1107/S1600536811022781
PMCID: PMC3152059
PMID: 21836962
The asymmetric unit of the title compound, [Cd(C7H7N2O4)2(H2O)2]·2H2O, consists of one CdII ion, one 4-carboxy-2-ethyl-1H-imidazole-5-carboxylate anion, one coordinated water molecule and one lattice water molecule. The CdII ion lies on a twofold axis, and is hexacoordinated by four O atoms from water molecules and carboxylate groups and two N atoms from two imidazole rings, in a distorted octahedral arrangement. An extensive framework of N—H⋯O and O—H⋯O hydrogen bonds with the participation of coordinated and free water molecules is found in the crystal structure, which contributes to the formation of a three-dimensional structure.
doi:10.1107/S1600536811021428
PMCID: PMC3151988
PMID: 21836881
In the title compound, [Mn(C7H7N2O4)2(H2O)2]·2C3H7NO, the central MnII ion, located on an inversion center, is hexacoordinated by four O atoms from two water molecules and two carboxylate groups, and two N atoms from two 4-carboxy-2-ethyl-1H-imidazole-5-carboxylate anions in a slightly distorted octahedral environment. The complex molecules and solvent molecules are connected via N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional polymeric structure parallel to (001).
doi:10.1107/S1600536811020071
PMCID: PMC3151971
PMID: 21836838
In the crystal structure of the title compound, [Zn(C7H7N2O4)2(H2O)2]·3H2O, the ZnII ion, located an inversion center, is N,O-chelated by two 5-carboxy-2-ethyl-1H-imidazole-4-carboxylate anions and further coordinated by two water molecules in a distorted octahedral geometry. The carboxy group links with the carboxylate group of the same ligand via an intramolecular O—H⋯O hydrogen bond. An extensive intermolecular N—H⋯O and O—H⋯O hydrogen-bonded network exists in the crystal structure. One disordered lattice water molecule is half-occupied and is located close to an inversion center.
doi:10.1107/S160053681101676X
PMCID: PMC3120609
PMID: 21754616
Anti-GM1 antibodies are present in some patients with autoimmune neurological disorders. These antibodies are most frequently associated with acute immune neuropathy called Guillain-Barré syndrome (GBS). Some clinical studies associate the presence of these antibodies with poor recovery in GBS. The patients with incomplete recovery have failure of nerve repair, particularly axon regeneration. Our previous work indicates that monoclonal antibodies can inhibit axon regeneration by engaging cell surface gangliosides (Lehmann et al., 2007). We asked whether passive transfer of human anti-GM1 antibodies from patients with GBS modulate axon regeneration in an animal model. Human anti-GM1 antibodies were compared with other GM1 ligands, cholera toxin B subunit and a monoclonal anti-GM1 antibody. Our results show that patient derived anti-GM1 antibodies and cholera toxin β subunit impair axon regeneration/repair after PNS injury in mice. Comparative studies indicated that the antibody/ligand-mediated inhibition of axon regeneration is dependent on antibody/ligand characteristics such as affinity-avidity and fine specificity. These data indicate that circulating immune effectors such as human autoantibodies, which are exogenous to the nervous system, can modulate axon regeneration/nerve repair in autoimmune neurological disorders such as GBS.
doi:10.1523/JNEUROSCI.2281-10.2010
PMCID: PMC3038609
PMID: 20631181
Guillain-Barré syndrome; anti-GM1 antibodies; ganglioside; regeneration; nerve repair; neuropathy
Anti-glycan antibodies directed against gangliosides are now considered the major immune effectors that induce damage to intact nerve fibers in some variants of the monophasic neuropathic disorders that comprise Guillain-Barré syndrome. Recent experimental studies elucidating the complexity of anti-glycan antibody-mediated pathobiologic effects on intact and injured nerves undergoing repair are discussed.
doi:10.3410/B2-21
PMCID: PMC2948347
PMID: 20948812
We assessed the potential of different MRI measures to detect and quantify skeletal muscle changes with denervation in two mouse models of denervation/neurogenic atrophy. Acute complete denervation and chronic partial denervation were examined in calf muscles after sciatic nerve axotomy and in transgenic SOD1G93A mice, respectively. Serial T2, diffusion tensor, and high resolution anatomical images were acquired, and compared to behavioral, histological, and electrophysiological data. Increase in muscle T2 signal was first detected after sciatic nerve axotomy. Progressive muscle atrophy could be monitored with MRI-based volume measurements, which correlated strongly with postmortem muscle mass measurements. Significant increase in muscle fractional anisotropy and decreases in secondary and tertiary eigenvalues obtained from diffusion tensor imaging (DTI) were observed after denervation. In SOD1G93A animals, muscle denervation was detected by elevated muscle T2 and atrophy in the medial gastrocnemius at 10 weeks. Changes in T2 and muscle volume were first observed in medial gastrocnemius and later in other calf muscles. Alterations in secondary and tertiary eigenvalues obtained from DTI were first observed in tibialis anterior and medial gastrocnemius muscles at age 12 weeks. We propose that MRI of skeletal muscle is a sensitive surrogate outcome measure of denervation atrophy in animal models of neuromuscular disorders, with potential applicability in preclinical therapeutic screening studies in rodents.
doi:10.1016/j.expneurol.2008.04.033
PMCID: PMC2532826
PMID: 18571650
MRI; denervation; muscle atrophy; muscle size; nerve injury; SOD1
In the title complex, [Fe(C10H6N3O4)2(H2O)2], the FeII atom is located on an inversion centre and is trans-coordinated by two N,O-bidentate 5-carboxy-2-(3-pyridyl)-1H-imidazole-4-carboxylate ligands and two water molecules, defining a distorted octahedral environment. A two-dimensional network of N—H⋯O and O—H⋯O hydrogen bonds extending parallel to (110) helps to stabilize the crystal packing.
doi:10.1107/S1600536809027457
PMCID: PMC2977312
PMID: 21583390
Wang, Xiaojie | Tang, Chunlei | Zhang, Gang | Li, Yingchun | Wang, Chenfang | Liu, Bo | Qu, Zhipeng | Zhao, Jie | Han, Qingmei | Huang, Lili | Chen, Xianming | Kang, Zhensheng
Background
Puccinia striiformis f. sp. tritici is a fungal pathogen causing stripe rust, one of the most important wheat diseases worldwide. The fungus is strictly biotrophic and thus, completely dependent on living host cells for its reproduction, which makes it difficult to study genes of the pathogen. In spite of its economic importance, little is known about the molecular basis of compatible interaction between the pathogen and wheat host. In this study, we identified wheat and P. striiformis genes associated with the infection process by conducting a large-scale transcriptomic analysis using cDNA-AFLP.
Results
Of the total 54,912 transcript derived fragments (TDFs) obtained using cDNA-AFLP with 64 primer pairs, 2,306 (4.2%) displayed altered expression patterns after inoculation, of which 966 showed up-regulated and 1,340 down-regulated. 186 TDFs produced reliable sequences after sequencing of 208 TDFs selected, of which 74 (40%) had known functions through BLAST searching the GenBank database. Majority of the latter group had predicted gene products involved in energy (13%), signal transduction (5.4%), disease/defence (5.9%) and metabolism (5% of the sequenced TDFs). BLAST searching of the wheat stem rust fungus genome database identified 18 TDFs possibly from the stripe rust pathogen, of which 9 were validated of the pathogen origin using PCR-based assays followed by sequencing confirmation. Of the 186 reliable TDFs, 29 homologous to genes known to play a role in disease/defense, signal transduction or uncharacterized genes were further selected for validation of cDNA-AFLP expression patterns using qRT-PCR analyses. Results confirmed the altered expression patterns of 28 (96.5%) genes revealed by the cDNA-AFLP technique.
Conclusion
The results show that cDNA-AFLP is a reliable technique for studying expression patterns of genes involved in the wheat-stripe rust interactions. Genes involved in compatible interactions between wheat and the stripe rust pathogen were identified and their expression patterns were determined. The present study should be helpful in elucidating the molecular basis of the infection process, and identifying genes that can be targeted for inhibiting the growth and reproduction of the pathogen. Moreover, this study can also be used to elucidate the defence responses of the genes that were of plant origin.
doi:10.1186/1471-2164-10-289
PMCID: PMC2717123
PMID: 19566949
The molecule of the title compound, C25H20N2OS2, has imposed twofold rotation symmetry. The dihedral angle formed by the two crystallographically independent phenyl rings is 79.23 (7)°. In the crystal packing, the molecules are linked by intermolecular N—H⋯O hydrogen bonds, forming chains running parallel to [102].
doi:10.1107/S1600536809016948
PMCID: PMC2969735
PMID: 21583116
Acute motor axonal neuropathy (AMAN) variant of Guillain-Barré syndrome is often associated with IgG anti-GM1 and -GD1a antibodies. The pathophysiological basis of antibody-mediated selective motor nerve dysfunction remains unclear. We investigated the effects of IgG anti-GM1 and -GD1a monoclonal antibodies (mAbs) on neuromuscular transmission and calcium influx in hemidiaphragm preparations and in cultured neurons, respectively, to elucidate mechanisms of Ab-mediated muscle weakness. Anti-GM1 and -GD1a mAbs depressed evoked quantal release to a significant yet different extent, without affecting postsynaptic currents. At equivalent concentrations, anti-GD1b, -GT1b, or sham mAbs did not affect neuromuscular transmission. At fourfold higher concentration, an anti-GD1b mAb (specificity described in immune sensory neuropathies) induced completely reversible blockade. In neuronal cultures, anti-GM1 and -GD1a mAbs significantly reduced depolarization-induced calcium influx. In conclusion, different anti-gangliosde mAbs induce distinct effects on presynaptic transmitter release by reducing calcium influx, suggesting that this is one mechanism of antibody-mediated muscle weakness in AMAN.
doi:10.1016/j.nbd.2007.07.008
PMCID: PMC2094038
PMID: 17720506
Guillain-Barré syndrome; AMAN; anti-ganglioside antibodies; gangliosides; immune neuropathies; neuromuscular junction; calcium influx
doi:10.1128/JVI.02773-06
PMCID: PMC1865937
Bovine viral diarrhea virus (BVDV) is a pestivirus that can establish a persistent infection in the developing fetus and has the ability to disable the production of type I interferon. In this report, we extend our previous observations that BVDV encodes a protein able to specifically block the activity of interferon regulatory factor 3 (IRF-3), a transcription factor essential for interferon promoter activation, by demonstrating that this is a property of the N-terminal protease fragment (NPro) of the BVDV polyprotein. Although BVDV infections cause relocalization of cellular IRF-3 from the cytoplasm to the nucleus early in infection, NPro blocks IRF-3 from binding to DNA. NPro has the additional property of targeting IRF-3 for polyubiquitination and subsequent destruction by cellular multicatalytic proteasomes. The autoprotease activity of NPro is not required for the inhibition of type I interferon induction or the targeting of IRF-3 for degradation.
doi:10.1128/JVI.01145-06
PMCID: PMC1642611
PMID: 16971436
Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest that influenza A virus, deposited as the birds begin their autumn migration, can be preserved in lake ice. As birds return in the spring, the ice melts, releasing the viruses. Therefore, temporal gene flow is facilitated between the viruses shed during the previous year and the viruses newly acquired by birds during winter months spent in the south. Above the Arctic Circle, the cycles of entrapment in the ice and release by melting can be variable in length, because some ice persists for several years, decades, or longer. This type of temporal gene flow might be a feature common to viruses that can survive entrapment in environmental ice and snow.
doi:10.1128/JVI.00986-06
PMCID: PMC1676296
PMID: 17035314
Budding yeast chitin synthase 2 (Chs2p), which lays down the primary septum, localizes to the mother–daughter neck in telophase. However, the mechanism underlying the timely neck localization of Chs2p is not known. Recently, it was found that a component of the exocyst complex, Sec3p–green fluorescent protein, arrives at the neck upon mitotic exit. It is not clear whether the neck localization of Chs2p, which is a cargo of the exocyst complex, was similarly regulated by mitotic exit. We report that Chs2p was restrained in the endoplasmic reticulum (ER) during metaphase. Furthermore, mitotic exit was sufficient to cause Chs2p neck localization specifically by triggering the Sec12p-dependent transport of Chs2p out of the ER. Chs2p was “forced” prematurely to the neck by mitotic kinase inactivation at metaphase, with chitin deposition occurring between mother and daughter cells. The dependence of Chs2p exit from the ER followed by its transport to the neck upon mitotic exit ensures that septum formation occurs only after the completion of mitotic events.
doi:10.1083/jcb.200604094
PMCID: PMC2064181
PMID: 16847101