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1.
    
ABCG1 and ABCG4 are highly homologous members of the ATP binding cassette (ABC) transporter family that regulate cellular cholesterol homeostasis. In adult mice, ABCG1 is known to be expressed in numerous cell types and tissues, whereas ABCG4 expression is limited to the central nervous system (CNS). Here, we show significant differences in expression of these two transporters during development. Examination of β-galactosidase-stained tissue sections from Abcg1−/−LacZ and Abcg4−/−LacZ knockin mice shows that ABCG4 is highly but transiently expressed both in hematopoietic cells and in enterocytes during development. In contrast, ABCG1 is expressed in macrophages and in endothelial cells of both embryonic and adult liver. We also show that ABCG1 and ABCG4 are both expressed as early as E12.5 in the embryonic eye and developing CNS. Loss of both ABCG1 and ABCG4 results in accumulation in the retina and/or brain of oxysterols, in altered expression of liver X receptor and sterol-regulatory element binding protein-2 target genes, and in a stress response gene. Finally, behavioral tests show that Abcg4−/− mice have a general deficit in associative fear memory. Together, these data indicate that loss of ABCG1 and/or ABCG4 from the CNS results in changes in metabolic pathways and in behavior.  相似文献   
2.
    
Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino‐alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)‐2‐amino‐1,3,4‐butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non‐chiral starting materials, by coupling a transketolase‐ and a transaminase‐catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor‐based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous‐flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase‐catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml?1. Following optimization of the transaminase‐catalyzed reaction, a volumetric activity of 10.8 U ml?1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous‐flow microreactors can be applied for the design and optimization of biocatalytic processes.
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3.
A range of feed supplements, including antibiotics, have been commonly used in poultry production to improve health and productivity. Alternative methods are needed to suppress pathogen loads and maintain productivity. As an alternative to antibiotics use, we investigated the ability of biochar, bentonite and zeolite as separate 4% feed additives, to selectively remove pathogens without reducing microbial richness and diversity in the gut. Neither biochar, bentonite nor zeolite made any significant alterations to the overall richness and diversity of intestinal bacterial community. However, reduction of some bacterial species, including some potential pathogens was detected. The microbiota of bentonite fed animals were lacking all members of the order Campylobacterales. Specifically, the following operational taxonomic units (OTUs) were absent: an OTU 100% identical to Campylobacter jejuni; an OTU 99% identical to Helicobacter pullorum; multiple Gallibacterium anatis (>97%) related OTUs; Bacteroides dorei (99%) and Clostridium aldenense (95%) related OTUs. Biochar and zeolite treatments had similar but milder effects compared to bentonite. Zeolite amended feed was also associated with significant reduction in the phylum Proteobacteria. All three additives showed potential for the control of major poultry zoonotic pathogens.  相似文献   
4.
    
Hu X  Nesic D  Stebbins CE 《Proteins》2006,62(2):421-434
Cytolethal distending toxins (CDTs) constitute a family of bacterial proteins that enter eukaryotic cells with genotoxic activity leading to cell cycle arrest and apoptosis. CDTs are widespread, having been found in a variety of Gram-negative pathogens with a broad tissue tropism. The recently determined crystal structure of the Haemophilus ducreyi CDT provides a powerful starting point for analysis of the structure and function in this toxin family. In this study, we apply comparative modeling and structural analysis to extend the experimental structural information to multiple CDT toxins from a diverse species. Analysis of structurally and functionally important residues in the active subunit, CdtB, and putative cell delivery elements, CdtA and CdtC, begins to establish the fundamental, mechanistic elements of this unique holotoxin. The results reveal that key structural features with important functional consequences are highly conserved across different CDTs, providing a blueprint for directed examination of functional hypotheses in a variety of pathogenic contexts.  相似文献   
5.
Flapless technique is a surgical approach of implant placement without raising a mucoperiosteal flap. Such approach has many advantages: shorter surgical treatment, minimal bleeding, postoperative discomfort for the patient is reduced; possibility of immediate loading of the inserted implant, faster procedure of implant placement and by that less time is needed for the complete implant-prosthetic restoration. Purpose of this pilot study was radiographic assessment of flapless technique and determination of its clinical values in comparison with two-stage dental implant technique through computerized densitometric analysis. The sample consisted of 10 patients with missing teeth in the premolar region in the upper jaw. An implant was placed in that position. In the first group of 5 patients the implants were inserted with the flapless technique, and in the other group of 5 patients implant insertion was done with a two-stage technique. All inserted implants were loaded with metal-ceramic crowns 3 months after placement. The patients were followed for 18 months through clinical follow-ups and radiovisiographical (RVG) images made after 3, 12 and 18 months. After comparing the average densities, the results showed similar decrease of density in both groups, conventional two-stage technique showed 3.24 and flapless technique 1.23. It can be concluded that flapless technique in everyday clinical usage has the same result as the two-stage dental implant technique.  相似文献   
6.
The role Hsp60 might play in various inflammatory and autoimmune diseases is under investigation, but little information exists pertaining to Hashimoto’s thyroiditis (HT). With the aim to fill this gap, in the present work, we directed our attention to Hsp60 participation in HT pathogenesis. We found Hsp60 levels increased in the blood of HT patients compared to controls. The chaperonin was immunolocalized in thyroid tissue specimens from patients with HT, both in thyrocytes and oncocytes (Hurthle cells) with higher levels compared to controls (goiter). In oncocytes, we found Hsp60 not only in the cytoplasm but also on the plasma membrane, as shown by double immunofluorescence performed on fine needle aspiration cytology. By bioinformatics, we found regions in the Hsp60 molecule with remarkable structural similarity with the thyroglobulin (TG) and thyroid peroxidase (TPO) molecules, which supports the notion that autoantibodies against TG and TPO are likely to recognize Hsp60 on the plasma membrane of oncocytes. This was also supported by data obtained by ELISA, showing that anti-TG and anti-TPO antibodies cross-react with human recombinant Hsp60. Antibody-antigen (Hsp60) reaction on the cell surface could very well mediate thyroid cell damage and destruction, perpetuating inflammation. Experiments with recombinant Hsp60 did not show stimulation of cytokine production by peripheral blood mononuclear cells from HT patients. All together, these results led us to hypothesize that Hsp60 may be an active player in HT pathogenesis via an antibody-mediated immune mechanism.  相似文献   
7.
Investigations of effective, orally active, and safe antidiabetic metallopharmaceuticals have been carried out during the last two decades. It has been reported that tungsten compounds mimic the action of insulin in intact cell systems. As insulin mimetics, the most investigated tungsten compound was sodium tungstate (ST), rarely investigated was tungstophosphoric acid (WPA), but never alanine complex of tungstophosphoric acid (WPA-A). In this study, the insulin mimetic activity of three different tungsten compounds, ST, WPA, and WPA-A, was evaluated by means of in vitro measurements of the glucose uptake and inhibition of free fatty acids release from epinephrine-treated isolated rat white adipocytes. We investigated the influence of concentration (lower and higher, 0.1 and 1.0 mM, respectively) and solvent: isotonic salt solution—saline (0.9% w/v of NaCl) and dimethyl sulfoxide (DMSO; 2% v/v), on the biological effect of tested compounds. Our experimental data showed that all of the three investigated tungsten compounds possess insulin mimetic activity in vitro on the isolated adipocytes. Influence of concentration and solvents on insulin mimetic effect for the certain tungsten compounds were: WPA was shown effect independently of concentration and solvents; higher concentration and DMSO were significant decreasing insulin mimetic effect of ST; lower concentration and saline led to decreasing effect of WPA-A. Generally, there were no differences in insulin mimetic effect of three tungsten compounds in lower concentration and dissolved in DMSO. When saline was used as solvent, it was needed higher concentration of investigated compounds to accomplish the same effect. In conclusion, our results suggest that low concentration (0.1 mM) of ST, WPA, and WPA-A dissolved in 2% DMSO could be the good candidates for in vivo investigation of their antidiabetic properties.  相似文献   
8.
Left-right asymmetry in vertebrates is initiated in an early embryonic structure called the ventral node in human and mouse, and the gastrocoel roof plate (GRP) in the frog. Within these structures, each epithelial cell bears a single motile cilium, and the concerted beating of these cilia produces a leftward fluid flow that is required to initiate left-right asymmetric gene expression. The leftward fluid flow is thought to result from the posterior tilt of the cilia, which protrude from near the posterior portion of each cell''s apical surface. The cells, therefore, display a morphological planar polarization. Planar cell polarity (PCP) is manifested as the coordinated, polarized orientation of cells within epithelial sheets, or as directional cell migration and intercalation during convergent extension. A set of evolutionarily conserved proteins regulates PCP. Here, we provide evidence that vertebrate PCP proteins regulate planar polarity in the mouse ventral node and in the Xenopus gastrocoel roof plate. Asymmetric anterior localization of VANGL1 and PRICKLE2 (PK2) in mouse ventral node cells indicates that these cells are planar polarized by a conserved molecular mechanism. A weakly penetrant Vangl1 mutant phenotype suggests that compromised Vangl1 function may be associated with left-right laterality defects. Stronger functional evidence comes from the Xenopus GRP, where we show that perturbation of VANGL2 protein function disrupts the posterior localization of motile cilia that is required for leftward fluid flow, and causes aberrant expression of the left side-specific gene Nodal. The observation of anterior-posterior PCP in the mouse and in Xenopus embryonic organizers reflects a strong evolutionary conservation of this mechanism that is important for body plan determination.  相似文献   
9.
Abstract Fanconi anemia (FA) is a rare cancer-prone genetic disorder characterized by progressive bone marrow failure, chromosomal instability and redox abnormalities. There is much biochemical and genetic data, which strongly suggest that FA cells experience increased oxidative stress. The present study was designed to elucidate if differences in oxidant state exist between control, idiopathic bone marrow failure (idBMF) and FA cells, and to analyze oxidant state of cells in FA heterozygous carriers as well. The results of the present study confirm an in vivo prooxidant state of FA cells and clearly indicate that FA patients can be distinguished from idBMF patients based on the oxidant state of cells. Female carriers of FA mutation also exhibited hallmarks of an in vivo prooxidant state behaving in a similar manner as FA patients. On the other hand, the oxidant state of cells in FA male carriers and idBMF families failed to show any significant difference vs. controls. We demonstrate that the altered oxidant state influences susceptibility of cells to apoptosis in both FA patients and female carriers. The results highlight the need for further research of the possible role of mitochondrial inheritance in the pathogenesis of FA.  相似文献   
10.

Background and Aim

Free radicals are implicated in the aetiology of gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. Strawberries are common and important fruit due to their high content of essential nutrient and beneficial phytochemicals which seem to have relevant biological activity on human health. In the present study we investigated the antioxidant and protective effects of three strawberry extracts against ethanol-induced gastric mucosa damage in an experimental in vivo model and to test whether strawberry extracts affect antioxidant enzyme activities in gastric mucosa.

Methods/Principal Findings

Strawberry extracts were obtained from Adria, Sveva and Alba cultivars. Total antioxidant capacity and radical scavenging capacity were performed by TEAC, ORAC and electron paramagnetic resonance assays. Identification and quantification of anthocyanins was carried out by HPLC-DAD-MS analyses. Different groups of animals received 40 mg/day/kg body weight of strawberry crude extracts for 10 days. Gastric damage was induced by ethanol. The ulcer index was calculated together with the determination of catalase and SOD activities and MDA contents. Strawberry extracts are rich in anthocyanins and present important antioxidant capacity. Ethanol caused severe gastric damage and strawberry consumption protected against its deleterious role. Antioxidant enzyme activities increased significantly after strawberry extract intake and a concomitantly decrease in gastric lipid peroxidation was found. A significant correlation between total anthocyanin content and percent of inhibition of ulcer index was also found.

Conclusions

Strawberry extracts prevented exogenous ethanol-induced damage to rats'' gastric mucosa. These effects seem to be associated with the antioxidant activity and phenolic content in the extract as well as with the capacity of promoting the action of antioxidant enzymes. A diet rich in strawberries might exert a beneficial effect in the prevention of gastric diseases related to generation of reactive oxygen species.  相似文献   
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