607 research outputs found
Altering Host Resistance to Infections through Microbial Transplantation
Host resistance to bacterial infections is thought to be dictated by host genetic factors. Infections by the natural murine enteric pathogen Citrobacter rodentium (used as a model of human enteropathogenic and enterohaemorrhagic E. coli infections) vary between mice strains, from mild self-resolving colonization in NIH Swiss mice to lethality in C3H/HeJ mice. However, no clear genetic component had been shown to be responsible for the differences observed with C. rodentium infections. Because the intestinal microbiota is important in regulating resistance to infection, and microbial composition is dependent on host genotype, it was tested whether variations in microbial composition between mouse strains contributed to differences in βhostβ susceptibility by transferring the microbiota of resistant mice to lethally susceptible mice prior to infection. Successful transfer of the microbiota from resistant to susceptible mice resulted in delayed pathogen colonization and mortality. Delayed mortality was associated with increased IL-22 mediated innate defense including antimicrobial peptides Reg3Ξ³ and Reg3Ξ², and immunono-neutralization of IL-22 abrogated the beneficial effect of microbiota transfer. Conversely, depletion of the native microbiota in resistant mice by antibiotics and transfer of the susceptible mouse microbiota resulted in reduced innate defenses and greater pathology upon infection. This work demonstrates the importance of the microbiota and how it regulates mucosal immunity, providing an important factor in susceptibility to enteric infection. Transfer of resistance through microbial transplantation (bacteriotherapy) provides additional mechanisms to alter βhostβ resistance, and a novel means to alter enteric infection and to study host-pathogen interactions
Nickel Antidot Arrays on Anodic Alumina Substrates
Large area nickel antidot arrays with density up to 10^10 /cm^2 have been
fabricated by depositing nickel onto anodic aluminum oxide membranes that
contain lattices of nanopores. Electron microscopy images show a high degree of
order of the antidot arrays. Various sizes and shapes of the antidots were
observed with increasing thickness of the deposited nickel. New features appear
in the antidot arrays in both magnetization and transport measurements when the
external magnetic field is parallel to the current direction, including an
enhancement and a nonmonotonous field dependence of the magnetoresistance,
larger values of the coercive field and remanence moment, and smaller
saturation field
Composição quΓmica e tamanho de grΓ£os de diferentes partes do dossel de cultivares de soja de hΓ‘bito de crescimento determinado e indeterminado.
O teor de proteΓna em soja Γ© fundamental para qualidade do farelo. Produtividade elevada das atuais cultivares, entre outros fatores, tem contribuΓdo para reduzir o teor desse composto. Desuniformidade na maturação de grΓ£os, devido aos grΓ£os verdes Γ© outro fator importante e que causa acidez no Γ³leo de soja. O objetivo desse trabalho foi verificar como esses fatores se comportam em cultivares de soja de hΓ‘bitos de crescimento determinado: BMX Ativa RR (GM 5.6) e A 6411 RR (GM 6.3), e indeterminado: BRS 6203 RR (GM 6.2) e BRS 5601 RR (GM 5.6). O experimento foi conduzido na Embrapa Trigo, semeado em 24/11/2015, em parcelas de 4 fileiras de 4 metros (50 cm de espaΓ§amentos entre linhas e 15 cm entre plantas). O desenho experimental foi blocos ao acaso com trΓͺs repetiçáes. Da Γ‘rea ΓΊtil da parcela foram colhidas 10 plantas, que foram divididas em suas partes inferior, intermediΓ‘ria e superior do dossel. Nestes extratos foram observados peso total de grΓ£os, peso de 100 grΓ£os, percentagem de Γ³leo e proteΓna por NIR. Os dados foram analisados por ANOVA e as mΓ©dias comparadas pelo teste de Duncan (SASM-Agri). Os resultados mostraram que o teor de Γ³leo nΓ£o variou entre as partes da planta. O teor de proteΓna foi maior na parte superior do dossel das plantas de hΓ‘bito de crescimento determinado, enquanto que as plantas de hΓ‘bito indeterminado, nΓ£o mostraram diferenΓ§as entre as diferentes partes, indicando possΓvel melhor incidΓͺncia de radiação solar para a planta inteira. Houve uniformidade de maturação nas cultivares analisadas para as condiçáes dessa safra e Γ©poca de colheita (11/04/2016). O tamanho dos grΓ£os foi semelhante entre as partes das plantas para todas as cultivares. A produção de grΓ£o foi maior no extrato intermediΓ‘rio do dossel das cultivares de hΓ‘bito determinado. As cultivares BRS 6203 RR e BRS 5601 RR, apresentaram produção de grΓ£os relativamente uniforme em toda a extensΓ£o do caule da planta. HΓ‘bito de crescimento indeterminado, hoje preferido pelos produtores, parece nΓ£o interferir no teor proteico do grΓ£o de soja.Editado por Tammy Aparecida Manabe Kiihl
MOG-IgG in primary and secondary chronic progressive multiple sclerosis: a multicenter study of 200 patients and review of the literature
Background: Antibodies to human full-length myelin oligodendrocyte glycoprotein (MOG-IgG) as detected by new-generation cell-based assays have recently been described in patients presenting with acute demyelinating disease of the central nervous system, including patients previously diagnosed with multiple sclerosis (MS). However, only limited data are available on the relevance of MOG-IgG testing in patients with chronic progressive demyelinating disease. It is unclear if patients with primary progressive MS (PPMS) or secondary progressive MS (SPMS) should routinely be tested for MOG-IgG.
Objective: To evaluate the frequency of MOG-IgG among patients classified as having PPMS or SPMS based on current diagnostic criteria.
Methods: For this purpose, we retrospectively tested serum samples of 200 patients with PPMS or SPMS for MOG-IgG using cell-based assays. In addition, we performed a review of the entire English language literature on MOG-IgG published between 2011 and 2017.
Results: None of 139 PPMS and 61 SPMS patients tested was positive for MOG-IgG. Based on a review of the literature, we identified 35 further MOG-IgG tests in patients with PPMS and 55 in patients with SPMS; the only reportedly positive sample was positive just at threshold level and was tested in a non-IgG-specific assay. In total, a single borderlineΒ positive result was observed among 290 tests.
Conclusion: Our data suggest thatΒ MOG-IgGΒ is absent or extremely rare among patients with PPMS or SPMS.Β Routine screening of patients with typical PPMS/SPMS for MOG-IgG seems not to be justified
Neonatal umbilical cord blood transplantation halts skeletal disease progression in the murine model of MPS-I
Umbilical cord blood (UCB) is a promising source of stem cells to use in early haematopoietic stem
cell transplantation (HSCT) approaches for several genetic diseases that can be diagnosed at birth. Mucopolysaccharidosis type I (MPS-I) is a progressive multi-system disorder caused by deficiency
of lysosomal enzyme Ξ±-L-iduronidase, and patients treated with allogeneic HSCT at the onset
have improved outcome, suggesting to administer such therapy as early as possible. Given that
the best characterized MPS-I murine model is an immunocompetent mouse, we here developed a transplantation system based on murine UCB. With the final aim of testing the therapeutic efficacy of UCB in MPS-I mice transplanted at birth, we first defined the features of murine UCB cells and demonstrated that they are capable of multi-lineage haematopoietic repopulation of myeloablated adult mice similarly to bone marrow cells. We then assessed the effectiveness of murine UCB cells transplantation in busulfan-conditioned newborn MPS-I mice. Twenty weeks after treatment, iduronidase activity was increased in visceral organs of MPS-I animals, glycosaminoglycans storage was reduced, and skeletal phenotype was ameliorated. This study explores a potential therapy for MPS-I at a very early stage in life and represents a novel model to test UCB-based transplantation approaches for various diseases
Quantum Imaging with Incoherently Scattered Light from a Free-Electron Laser
The advent of accelerator-driven free-electron lasers (FEL) has opened new
avenues for high-resolution structure determination via diffraction methods
that go far beyond conventional x-ray crystallography methods. These techniques
rely on coherent scattering processes that require the maintenance of
first-order coherence of the radiation field throughout the imaging procedure.
Here we show that higher-order degrees of coherence, displayed in the intensity
correlations of incoherently scattered x-rays from an FEL, can be used to image
two-dimensional objects with a spatial resolution close to or even below the
Abbe limit. This constitutes a new approach towards structure determination
based on incoherent processes, including Compton scattering, fluorescence
emission or wavefront distortions, generally considered detrimental for imaging
applications. Our method is an extension of the landmark intensity correlation
measurements of Hanbury Brown and Twiss to higher than second-order paving the
way towards determination of structure and dynamics of matter in regimes where
coherent imaging methods have intrinsic limitations
Social interaction, noise and antibiotic-mediated switches in the intestinal microbiota
The intestinal microbiota plays important roles in digestion and resistance
against entero-pathogens. As with other ecosystems, its species composition is
resilient against small disturbances but strong perturbations such as
antibiotics can affect the consortium dramatically. Antibiotic cessation does
not necessarily restore pre-treatment conditions and disturbed microbiota are
often susceptible to pathogen invasion. Here we propose a mathematical model to
explain how antibiotic-mediated switches in the microbiota composition can
result from simple social interactions between antibiotic-tolerant and
antibiotic-sensitive bacterial groups. We build a two-species (e.g. two
functional-groups) model and identify regions of domination by
antibiotic-sensitive or antibiotic-tolerant bacteria, as well as a region of
multistability where domination by either group is possible. Using a new
framework that we derived from statistical physics, we calculate the duration
of each microbiota composition state. This is shown to depend on the balance
between random fluctuations in the bacterial densities and the strength of
microbial interactions. The singular value decomposition of recent metagenomic
data confirms our assumption of grouping microbes as antibiotic-tolerant or
antibiotic-sensitive in response to a single antibiotic. Our methodology can be
extended to multiple bacterial groups and thus it provides an ecological
formalism to help interpret the present surge in microbiome data.Comment: 20 pages, 5 figures accepted for publication in Plos Comp Bio.
Supplementary video and information availabl
Differential Expression of Rubisco in Sporophytes and Gametophytes of Some Marine Macroalgae
Rubisco (ribulose-1, 5-bisphosphate carboxylase/oxygenase), a key enzyme of photosynthetic CO2 fixation, is one of the most abundant proteins in both higher plants and algae. In this study, the differential expression of Rubisco in sporophytes and gametophytes of four seaweed species β Porphyra yezoensis, P. haitanensis, Bangia fuscopurpurea (Rhodophyte) and Laminaria japonica (Phaeophyceae) β was studied in terms of the levels of transcription, translation and enzyme activity. Results indicated that both the Rubisco content and the initial carboxylase activity were notably higher in algal gametophytes than in the sporophytes, which suggested that the Rubisco content and the initial carboxylase activity were related to the ploidy of the generations of the four algal species
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