The Soluble Interleukin-6 Receptor Is a Mediator of Hematopoietic and Skeletal Actions of Parathyroid Hormone

Both PTH and IL-6 signaling play pivotal roles in hematopoiesis and skeletal biology, but their interdependence is unclear. The purpose of this study was to evaluate the effect of IL-6 and soluble IL-6 receptor (sIL-6R) on hematopoietic and skeletal actions of PTH. In the bone microenvironment, PTH stimulated sIL-6R protein levels in primary osteoblast cultures in vitro and bone marrow in vivo in both IL-6^+/+ and IL-6^−/− mice. PTH-mediated hematopoietic cell expansion was attenuated in IL-6^−/− compared with IL-6^+/+ bone marrow, whereas sIL-6R treatment amplified PTH actions in IL-6^−/− earlier than IL-6^+/+ marrow cultures. Blocking sIL-6R signaling with sgp130 (soluble glycoprotein 130 receptor) inhibited PTH-dependent hematopoietic cell expansion in IL-6^−/− marrow. In the skeletal system, although intermittent PTH administration to IL-6^+/+ and IL-6^−/− mice resulted in similar anabolic actions, blocking sIL-6R significantly attenuated PTH anabolic actions. sIL-6R showed no direct effects on osteoblast proliferation or differentiation in vitro; however, it up-regulated myeloid cell expansion and production of the mesenchymal stem cell recruiting agent, TGF-β1 in the bone marrow microenvironment. Collectively, sIL-6R demonstrated orphan function and mediated PTH anabolic actions in bone in association with support of myeloid lineage cells in the hematopoietic system.     

Negative Regulation of Interferon-induced Transmembrane Protein 3 by SET7-mediated Lysine Monomethylation

Although lysine methylation is classically known to regulate histone function, its role in modulating antiviral restriction factor activity remains uncharacterized. Interferon-induced transmembrane protein 3 (IFITM3) was found monomethylated on its lysine 88 residue (IFITM3-K88me1) to reduce its antiviral activity, mediated by the lysine methyltransferase SET7. Vesicular stomatitis virus and influenza A virus infection increased IFITM3-K88me1 levels by promoting the interaction between IFITM3 and SET7, suggesting that this pathway could be hijacked to support infection; conversely, IFN-α reduced IFITM3-K88me1 levels. These findings may have important implications in the design of therapeutics targeting protein methylation against infectious diseases.     

Systematic Identification of H274Y Compensatory Mutations in Influenza A Virus Neuraminidase by High-Throughput Screening

Compensatory mutations contribute to the appearance of the oseltamivir resistance substitution H274Y in the neuraminidase (NA) gene of H1N1 influenza viruses. Here, we describe a high-throughput screening method utilizing error-prone PCR and next-generation sequencing to comprehensively screen NA genes for H274Y compensatory mutations. We found four mutations that can either fully (R194G, E214D) or partially (L250P, F239Y) compensate for the fitness deficiency of the H274Y mutant. The compensatory effect of E214D is applicable in both seasonal influenza virus strain A/New Caledonia/20/1999 and 2009 pandemic swine influenza virus strain A/California/04/2009. The technique described here has the potential to profile a gene at the single-nucleotide level to comprehend the dynamics of mutation space and fitness and thus offers prediction power for emerging mutant species.     

Spatial pattern characterization of linear polarization-sensitive backscattering Mueller matrix elements of human serum albumin sphere suspension

Human serum albumin (HSA) nanometer or micron particles represent promising drug-carrier systems. The azimuthal and radial variations of a linear polarization-sensitive backscattering Mueller matrix were experimentally studied in two cases: the scattering particle was smaller or larger in size to the probing wavelength of 780 nm. The results show that the twofold and fourfold structures are characteristic of small particle size suspension, whereas the eightfold structure is characteristic of large particle size suspension. Moreover, for both particle size suspensions, the element patterns have strong radial dependence when the suspension concentration and the incident power of laser change. In addition, for both particle size suspensions, the rotational symmetry of each element is lost in the case of oblique incidence but the multifold structure is maintained. Some suggestions for applications of Mueller matrix imaging in biomedical optics are provided.     

Quantifying Salmonella Population Dynamics in Water and Biofilms

Members of the bacterial genus Salmonella are recognized worldwide as major zoonotic pathogens often found to persist in non-enteric environments including heterogeneous aquatic biofilms. In this study, Salmonella isolates that had been detected repeatedly over time in aquatic biofilms at different sites in Spring Lake, San Marcos, Texas, were identified as serovars Give, Thompson, Newport and -:z10:z39. Pathogenicity results from feeding studies with the nematode Caenorhabditis elegans as host confirmed that these strains were pathogenic, with Salmonella-fed C. elegans dying faster (mean survival time between 3 and 4 days) than controls, i.e., Escherichia coli-fed C. elegans (mean survival time of 9.5 days). Cells of these isolates inoculated into water at a density of up to 10⁶?ml^?1 water declined numerically by 3 orders of magnitude within 2 days, reaching the detection limit of our quantitative polymerase chain reaction (qPCR)-based quantification technique (i.e., 10³ cells ml^?1). Similar patterns were obtained for cells in heterogeneous aquatic biofilms developed on tiles and originally free of Salmonella that were kept in the inoculated water. Cell numbers increased during the first days to more than 10⁷ cells cm^?2, and then declined over time. Ten-fold higher cell numbers of Salmonella inoculated into water or into biofilm resulted in similar patterns of population dynamics, though cells in biofilms remained detectable with numbers around 10⁴ cells cm^?2 after 4 weeks. Independent of detectability by qPCR, samples of all treatments harbored viable salmonellae that resembled the inoculated isolates after 4 weeks of incubation. These results demonstrate that pathogenic salmonellae were isolated from heterogeneous aquatic biofilms and that they could persist and stay viable in such biofilms in high numbers for some time.     

Mamu-B genes and their allelic repertoires in different populations of Chinese-origin rhesus macaques

Since rhesus monkeys of Chinese origin have gained greater utilization in recent years, it is urgent to investigate the major histocompatibility complex (MHC) immunogenetics of Chinese rhesus macaques. In this study, we identified 81 Mamu-B sequences using complementary DNA cloning and sequencing on a cohort of 58 rhesus monkeys derived from three local populations of China. Twenty of these Mamu-B alleles are novel and four of them represent new lineages. Although more alleles are shared among different populations than Mamu-A locus, the Mamu-B allelic repertoires found in these three populations of Chinese macaques are largely independent, which underscores the MHC polymorphism among different populations of Chinese rhesus macaques. Our results are an important addition to the limited MHC immunogenetic information available for rhesus macaques of Chinese origin.     

Diversity of Wolbachia in Natural Populations of Spider Mites (genus Tetranychus): Evidence for Complex Infection History and Disequilibrium Distribution

Wolbachia are endosymbiotic bacteria that commonly infect arthropods and cause reproductive disorders in host. Within several Tetranychus species, Wolbachia have been detected and shown to affect their reproduction. However, little is known about their transmission and distribution patterns in natural populations of Tetranychus species. Here, we used multilocus sequence typing to confirm Wolbachia infection status and examined the relationship between Wolbachia infection status and host phylogeny, mitochondrial diversity, and geographical range in five Tetranychus species (Tetranychus truncatus, Tetranychus urticae, Tetranychus pueraricola, Tetranychus phaselus, and Tetranychus kanzawai) from 21 populations in China. The prevalence of Wolbachia within the five Tetranychus species ranged from 31.4 to 100 %, and the strains were remarkably diverse. Together, these observations indicate that Wolbachia was introduced to these populations on multiple separate occasions. As in other arthropods, the same Tetranychus species can accommodate very different strains, and identical Wolbachia occasionally infect different species. These observations suggest that Wolbachia are transmitted both vertically and horizontally. Horizontally, transmission is probably mediated by the host plants. The distribution patterns of Wolbachia were quite different among populations of the same species, suggesting that the dynamics of Wolbachia in nature may be affected by ecological and other factors.