Modulation of Pseudomonas aeruginosa lipopolysaccharide-induced lung inflammation by chronic iron overload in rat

Iron constitutes a critical nutrient source for bacterial growth, so iron overload is a risk factor for bacterial infections. This study aimed at investigating the role of iron overload in modulating bacterial endotoxin-induced lung inflammation. Weaning male Wistar rats were intraperitoneally injected with saline or iron sucrose [15 mg kg(-1) body weight (bw), 3 times per week, 4 weeks]. They were then intratracheally injected with Pseudomonas aeruginosa lipopolysaccharide (LPS) (5 μg kg(-1) bw) or saline. Inflammatory indices were evaluated 4 or 18 h post-LPS/saline injection. At 4 h, LPS-treated groups revealed significant increases in the majority of inflammatory parameters (LPS-binding protein (LBP), immune cell recruitment, inflammatory cytokine synthesis, myeloperoxidase activity, and alteration of alveolar-capillary permeability), as compared with control groups. At 18 h, these parameters reduced strongly with the exception for LBP content and interleukin (IL)-10. In parallel, iron acted as a modulator of immune cell recruitment; LBP, tumor necrosis factor-α, cytokine-induced neutrophil chemoattractant 3, and IL-10 synthesis; and alveolar-capillary permeability. Therefore, P. aeruginosa LPS may only act as an acute lung inflammatory molecule, and iron overload may modulate lung inflammation by enhancing different inflammatory parameters. Thus, therapy for iron overload may be a novel and efficacious approach for the prevention and treatment of bacterial lung inflammations.     

Categorical perception of human female physical attractiveness and health

Using realistic three-dimensional female body models, we found evidence for a categorical perception of female physical attractiveness and health in male and female Caucasian observers. In a rating task, we showed that these bodies were rated for attractiveness or health in the same way as real bodies. In a two-alternative forced-choice task, we showed that these bodies were categorized into attractive vs. unattractive or healthy vs. unhealthy nonlinearly, which allowed us to estimate the position of a categorical boundary between attractive and unattractive or healthy and unhealthy bodies. In a delayed match-to-sample task, we measured the sensitivity of discrimination between pairs of bodies. We found significantly better discrimination for pairs that crossed the attractive/unattractive or healthy/unhealthy boundary than pairs that did not, even though the physical changes in both conditions were identical. Thus, categorical perception enhances the perception of physical changes that cross the boundary between discrete perceptual categories of important judgments such as attractiveness or health, which can be a cue for mate selection.     

A New Species of Cleisostoma (Orchidaceae) from the Hon Ba Nature Reserve in Vietnam: A Multidisciplinary Assessment

A new species, Cleisostoma yersinii J. Ponert & Vuong, is described and illustrated based on the material collected in the Hon Ba Nature Reserve in southern Vietnam. In addition to conventional (macro)morphological examination we comparatively investigated root and leaf anatomy (using light and fluorescent microscopy), assessed nectar characteristics (using HPLC analysis), determined nuclear genome size (using DNA flow cytometry) and reconstructed phylogenetic relationships (using nrITS sequences). Cleisostoma yersinii differs from its putative closest relative C. birmanicum in wider and shorter leaves, larger flowers, distinct lip with S-shaped tip of the mid-lobe, and a shallow spur with two large nectar sacks separated by prominent calli and septum. Nectar is sucrose-dominant and very rich in sugars. Stomata are developed on both sides of the leaf and have prominent hyperstomatal chambers and substomatal cavities. Roots with well-developed exodermis and tracheoidal idioblasts are covered by a two-layer Vanda-type velamen. Chloroplasts occur not only in the cortex but are also abundant in the stele. Mean 1C-value was estimated to 2.57 pg DNA. An updated identification key is provided for SE Asian sections and all Vietnamese species of Cleisostoma.     

Analysis of YfgL and YaeT interactions through bioinformatics, mutagenesis, and biochemistry

In Escherichia coli, YaeT, together with four lipoproteins, YfgL, YfiO, NlpB, and SmpA, forms a complex that is essential for β-barrel outer membrane protein biogenesis. Data suggest that YfgL and YfiO make direct but independent physical contacts with YaeT. Whereas the YaeT-YfiO interaction needs NlpB and SmpA for complex stabilization, the YaeT-YfgL interaction does not. Using bioinformatics, genetics, and biochemical approaches, we have identified three residues, L173, L175, and R176, in the mature YfgL protein that are critical for both function and interactions with YaeT. A single substitution at any of these sites produces no phenotypic defect, but two or three simultaneous alterations produce mild or yfgL-null phenotypes, respectively. Interestingly, biochemical data show that all YfgL variants, including those with single substitutions, have weakened in vivo YaeT-YfgL interaction. These defects are not due to mislocalization or low steady-state levels of YfgL. Cysteine-directed cross-linking data show that the region encompassing L173, L175, and R176 makes direct contact with YaeT. Using the same genetic and biochemical strategies, it was found that altering residues D227 and D229 in another region of YfgL from E221 to D229 resulted in defective YaeT bindings. In contrast, mutational analysis of conserved residues V319 to H328 of YfgL shows that they are important for YfgL biogenesis but not YfgL-YaeT interactions. The five YfgL mutants defective in YaeT associations and the yfgL background were used to show that SurA binds to YaeT (or another complex member) without going through YfgL.     

Enhancing the luminescence of Eu3+/Eu2+ ion‐doped hydroxyapatite by fluoridation and thermal annealing

This paper reports a novel way for the synthesis of a europium (Eu)‐doped fluor‐hydroxyapatite (FHA) nanostructure to control the luminescence of hydroxyapatite nanophosphor, particularly, by applying optimum fluorine concentrations, annealed temperatures and pH value. The Eu‐doped FHA was made using the co‐precipitation method followed by thermal annealing in air and reducing in a H₂ atmosphere to control the visible light emission center of the nanophosphors. The intensities of the OH^? group decreased with the increasing fluorine concentrations. For the specimens annealed in air, the light emission center of the nanophosphor was 615 nm, which was emission from the Eu³⁺ ion. However, when they were annealed in reduced gas (Ar + 5% H₂), a 448 nm light emission center from the Eu²⁺ ion of FHA was observed. The presence of fluorine in Eu‐doped FHA resulted in a significant enhancement of nanophosphor luminescence, which has potential application in light emission and nanomedicine.     

Regulated expression of pathogen-associated molecular pattern molecules in Staphylococcus epidermidis: quorum-sensing determines pro-inflammatory capacity and production of phenol-soluble modulins

Phenol-soluble modulin (PSM) is a peptide complex produced by the nosocomial pathogen Staphylococcus epidermidis that has a strong capacity to activate the human innate immune response. We developed a novel method based on liquid chromatography-mass spectrometry (LC-MS) to quantify the production of the individual PSM components. Each PSM peptide was abundant in most of the 76 S epidermidis strains tested. Importantly, none of the PSM components were secreted by an agr mutant strain, indicating that PSM synthesis is regulated strictly by the agr quorum-sensing system. Furthermore, the agr mutant strain failed to elicit production of TNFalpha by human myeloid cells and induced significantly less neutrophil chemotaxis compared with the wild-type strain. Thus, quorum-sensing in S. epidermidis dramatically influenced activation of human host defence. We propose that an agr quorum-sensing mechanism facilitates growth and survival in infected hosts by adapting production of the pro-inflammatory PSMs to the stage of infection.     

Fes mediates the IL-4 activation of insulin receptor substrate-2 and cellular proliferation

Although Jak kinases are essential for initiating cytokine signaling, the role of other nonreceptor tyrosine kinases in this process remains unclear. We have examined the role of Fes in IL-4 signaling. Examination of Jak1-deficient cell lines demonstrates that Jak1 is required for the activation of Fes by IL-4. Experiments studying signaling molecules activated by IL-4 receptor suggest that IL-4 signaling can be subdivided into Fes-dependent and Fes-independent pathways. Overexpression of kinase-inactive Fes blocks the IL-4 activation of insulin receptor substrate-2, but not STAT6. Fes appears to be a downstream kinase from Jak1/Jak3 in this process. Further examination of downstream signaling demonstrates that kinase-inactive Fes inhibits the recruitment of phosphoinositide 3-kinase to the activated IL-4 receptor complex and decreases the activation of p70(S6k) kinase in response to IL-4. This inhibition correlates with a decrease in IL-4-induced proliferation. In contrast, mutant Fes does not inhibit the activation of Akt by IL-4. These data demonstrate that signaling pathways activated by IL-4 require different tyrosine kinases. This differential requirement predicts that specific kinase inhibitors may permit the disruption of specific IL-4-induced functions.     

Selective adhesion of extremophiles for scanning electron microscopy

Polyethyleneimine (PEI)-coated slides were used for attachment of unknown extremophiles and their cultures grown at high temperature and low pH. Selective adhesion of cells in natural samples and cultural isolates was compared to polylysine (PL) and several other coatings. PEI is superior to PL for adhesion of extremophiles.     

Histological study of Trichosomoides nasalis (Nematoda: Trichinelloidea) in the nasal cavities of the murid Arvicanthis niloticus, with associated pathology

Histological study of the nasal cavities and upper maxillae of Arvicanthis niloticus naturally infected with Trichosomoides nasalis shows that the female worms reside in the epithelial monolayer of the nasal mucosa of the posterior and median cavities. Eggs laid by T. nasalis were infiltrated between the female body wall and the epithelial lining. Small groups of eggs, mixed with mucus and polymorphonuclear cells, were found in the nasal lumen, freed by rupture of the stretched epithelium. Two females and a few eggs were also found in the connective tissues. One male was found in a female uterus and two were apparently in the lumen of the nasal cavity but the surrounding tissues were disrupted. No male was identified in the lamina propria of the mucosa. However, significant inflammatory lesions occurred in the lamina propria, similar to those induced by the males of Anatrichosoma spp. which live in this part of the mucosa. In rodents, the lesions resulted in rhinosinusitis characterised by a lymphocytic infiltration leading to nasal obstruction.