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Jörg Barke Ryan F Seipke Sabine Grüschow Darren Heavens Nizar Drou Mervyn J Bibb Rebecca JM Goss Douglas W Yu Matthew I Hutchings 《BMC biology》2010,8(1):109
Background
Attine ants live in an intensely studied tripartite mutualism with the fungus Leucoagaricus gongylophorus, which provides food to the ants, and with antibiotic-producing actinomycete bacteria. One hypothesis suggests that bacteria from the genus Pseudonocardia are the sole, co-evolved mutualists of attine ants and are transmitted vertically by the queens. A recent study identified a Pseudonocardia-produced antifungal, named dentigerumycin, associated with the lower attine Apterostigma dentigerum consistent with the idea that co-evolved Pseudonocardia make novel antibiotics. An alternative possibility is that attine ants sample actinomycete bacteria from the soil, selecting and maintaining those species that make useful antibiotics. Consistent with this idea, a Streptomyces species associated with the higher attine Acromyrmex octospinosus was recently shown to produce the well-known antifungal candicidin. Candicidin production is widespread in environmental isolates of Streptomyces, so this could either be an environmental contaminant or evidence of recruitment of useful actinomycetes from the environment. It should be noted that the two possibilities for actinomycete acquisition are not necessarily mutually exclusive. 相似文献204.
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Hoorelbeke B Van Damme EJ Rougé P Schols D Van Laethem K Fouquaert E Balzarini J 《Retrovirology》2011,8(1):10-16
Background
In a recent report, the carbohydrate-binding specificities of the plant lectins Galanthus nivalis (GNA) and the closely related lectin from Zea mays (GNAmaize) were determined by glycan array analysis and indicated that GNAmaize recognizes complex-type N-glycans whereas GNA has specificity towards high-mannose-type glycans. Both lectins are tetrameric proteins sharing 64% sequence similarity.Results
GNAmaize appeared to be ~20- to 100-fold less inhibitory than GNA against HIV infection, syncytia formation between persistently HIV-1-infected HuT-78 cells and uninfected CD4+ T-lymphocyte SupT1 cells, HIV-1 capture by DC-SIGN and subsequent transmission of DC-SIGN-captured virions to uninfected CD4+ T-lymphocyte cells. In contrast to GNA, which preferentially selects for virus strains with deleted high-mannose-type glycans on gp120, prolonged exposure of HIV-1 to dose-escalating concentrations of GNAmaize selected for mutant virus strains in which one complex-type glycan of gp120 was deleted. Surface Plasmon Resonance (SPR) analysis revealed that GNA and GNAmaize interact with HIV IIIB gp120 with affinity constants (KD) of 0.33 nM and 34 nM, respectively. Whereas immobilized GNA specifically binds mannose oligomers, GNAmaize selectively binds complex-type GlcNAcβ1,2Man oligomers. Also, epitope mapping experiments revealed that GNA and the mannose-specific mAb 2G12 can independently bind from GNAmaize to gp120, whereas GNAmaize cannot efficiently bind to gp120 that contained prebound PHA-E (GlcNAcβ1,2man specific) or SNA (NeuAcα2,6X specific).Conclusion
The markedly reduced anti-HIV activity of GNAmaize compared to GNA can be explained by the profound shift in glycan recognition and the disappearance of carbohydrate-binding sites in GNAmaize that have high affinity for mannose oligomers. These findings underscore the need for mannose oligomer recognition of therapeutics to be endowed with anti-HIV activity and that mannose, but not complex-type glycan binding of chemotherapeutics to gp120, may result in a pronounced neutralizing activity against the virus. 相似文献206.
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Marco van der Toorn Dirk-Jan Slebos Harold G de Bruin Renee Gras Delaram Rezayat Lucie Jorge Koen Sandra Antoon JM van Oosterhout 《Respiratory research》2013,14(1):45
Background
Cigarette smoking (CS) is the most important risk factor for COPD, which is associated with neutrophilic airway inflammation. We hypothesize, that highly reactive aldehydes are critical for CS-induced neutrophilic airway inflammation.Methods
BALB/c mice were exposed to CS, water filtered CS (WF-CS) or air for 5 days. Levels of total particulate matter (TPM) and aldehydes in CS and WF-CS were measured. Six hours after the last exposure, inflammatory cells and cytokine levels were measured in lung tissue and bronchoalveolar lavage fluid (BALF). Furthermore, Beas-2b bronchial epithelial cells were exposed to CS extract (CSE) or WF-CS extract (WF-CSE) in the absence or presence of the aldehyde acrolein and IL-8 production was measured after 24 hrs.Results
Compared to CS, in WF-CS strongly decreased (CS; 271.1 ± 41.5 μM, WF-CS; 58.5 ± 8.2 μM) levels of aldehydes were present whereas levels of TPM were only slightly reduced (CS; 20.78 ± 0.59 mg, WF-CS; 16.38 ± 0.36 mg). The numbers of mononuclear cells in BALF (p<0.01) and lung tissue (p<0.01) were significantly increased in the CS- and WF-CS-exposed mice compared to air control mice. Interestingly, the numbers of neutrophils (p<0.001) in BALF and neutrophils and eosinophils (p<0.05) in lung tissue were significantly increased in the CS-exposed but not in WF-CS-exposed mice as compared to air control mice. Levels of the neutrophil and eosinophil chemoattractants KC, MCP-1, MIP-1α and IL-5 were all significantly increased in lung tissue from CS-exposed mice compared to both WF-CS-exposed and air control mice. Interestingly, depletion of aldehydes in WF-CS extract significantly reduced IL-8 production in Beas-2b as compared to CSE, which could be restored by the aldehyde acrolein.Conclusion
Aldehydes present in CS play a critical role in inflammatory cytokine production and neutrophilic- but not mononuclear airway inflammation. 相似文献210.
Rohola Hosseini Gerda EM Lamers Zlatan Hodzic Annemarie H Meijer Marcel JM Schaaf Herman P Spaink 《Autophagy》2014,10(10):1844-1857
High-resolution imaging of autophagy has been used intensively in cell culture studies, but so far it has been difficult to visualize this process in detail in whole animal models. In this study we present a versatile method for high-resolution imaging of microbial infection in zebrafish larvae by injecting pathogens into the tail fin. This allows visualization of autophagic compartments by light and electron microscopy, which makes it possible to correlate images acquired by the 2 techniques. Using this method we have studied the autophagy response against Mycobacterium marinum infection. We show that mycobacteria during the progress of infection are frequently associated with GFP-Lc3-positive vesicles, and that 2 types of GFP-Lc3-positive vesicles were observed. The majority of these vesicles were approximately 1 μm in size and in close vicinity of bacteria, and a smaller number of GFP-Lc3-positive vesicles was larger in size and were observed to contain bacteria. Quantitative data showed that these larger vesicles occurred significantly more in leukocytes than in other cell types, and that approximately 70% of these vesicles were positive for a lysosomal marker. Using electron microscopy, it was found that approximately 5% of intracellular bacteria were present in autophagic vacuoles and that the remaining intracellular bacteria were present in phagosomes, lysosomes, free inside the cytoplasm or occurred as large aggregates. Based on correlation of light and electron microscopy images, it was shown that GFP-Lc3-positive vesicles displayed autophagic morphology. This study provides a new approach for injection of pathogens into the tail fin, which allows combined light and electron microscopy imaging in vivo and opens new research directions for studying autophagy process related to infectious diseases. 相似文献