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11.
CA1 cells receive direct input from space-responsive cells in medial entorhinal cortex (MEC), such as grid cells, as well as more nonspatial cells in lateral entorhinal cortex (LEC). Because MEC projects preferentially to the proximal part of the CA1, bordering CA2, whereas LEC innervates only the distal part, bordering subiculum, we asked if spatial tuning is graded along the transverse axis of CA1. Tetrodes were implanted along the entire proximodistal axis of dorsal CA1 in rats. Data were recorded in cylinders large enough to elicit firing at more than one location in many neurons. Distal CA1 cells showed more dispersed firing and had a larger number of firing fields than proximal cells. Phase-locking of spikes to MEC theta oscillations was weaker in distal CA1 than in proximal CA1. The findings suggest that spatial firing in CA1 is organized transversally, with the strongest spatial modulation occurring in the MEC-associated proximal part. 相似文献
12.
Wouter A A de Steenhuijsen Piters Elisabeth G W Huijskens Anne L Wyllie Giske Biesbroek Menno R van den Bergh Reinier H Veenhoven Xinhui Wang Krzysztof Trzciński Marc J Bonten John W A Rossen Elisabeth A M Sanders Debby Bogaert 《The ISME journal》2016,10(1):97-108
Bacterial pneumonia is a major cause of morbidity and mortality in elderly. We hypothesize that dysbiosis between regular residents of the upper respiratory tract (URT) microbiome, that is balance between commensals and potential pathogens, is involved in pathogen overgrowth and consequently disease. We compared oropharyngeal microbiota of elderly pneumonia patients (n=100) with healthy elderly (n=91) by 16S-rRNA-based sequencing and verified our findings in young adult pneumonia patients (n=27) and young healthy adults (n=187). Microbiota profiles differed significantly between elderly pneumonia patients and healthy elderly (PERMANOVA, P<0.0005). Highly similar differences were observed between microbiota profiles of young adult pneumonia patients and their healthy controls. Clustering resulted in 11 (sub)clusters including 95% (386/405) of samples. We observed three microbiota profiles strongly associated with pneumonia (P<0.05) and either dominated by lactobacilli (n=11), Rothia (n=51) or Streptococcus (pseudo)pneumoniae (n=42). In contrast, three other microbiota clusters (in total n=183) were correlated with health (P<0.05) and were all characterized by more diverse profiles containing higher abundances of especially Prevotella melaninogenica, Veillonella and Leptotrichia. For the remaining clusters (n=99), the association with health or disease was less clear. A decision tree model based on the relative abundance of five bacterial community members in URT microbiota showed high specificity of 95% and sensitivity of 84% (89% and 73%, respectively, after cross-validation) for differentiating pneumonia patients from healthy individuals. These results suggest that pneumonia in elderly and young adults is associated with dysbiosis of the URT microbiome with bacterial overgrowth of single species and absence of distinct anaerobic bacteria. Whether the observed microbiome changes are a cause or a consequence of the development of pneumonia or merely coincide with disease status remains a question for future research. 相似文献
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14.
Hoeks FW Boon LA Studer F Wolff MO van der Schot F Vrabél P van der Lans RG Bujalski W Manelius A Blomsten G Hjorth S Prada G Luyben KCh Nienow AW 《Journal of industrial microbiology & biotechnology》2003,30(2):118-128
Foam disruption by agitation—the stirring as foam disruption (SAFD) technique—was scaled up to pilot and production scale
using Rushton turbines and an up-pumping hydrofoil impeller, the Scaba 3SHP1. The dominating mechanism behind SAFD—foam entrainment—was
also demonstrated at production scale. The mechanistic model for SAFD defines a fictitious liquid velocity generated by the
(upper) impeller near the dispersion surface, which is correlated with complete foam disruption. This model proved to be scalable,
thus enabling the model to be used for the design of SAFD applications. Axial upward pumping impellers appeared to be more
effective with respect to SAFD than Rushton turbines, as demonstrated by retrofitting a 12,000 l bioreactor, i.e. the triple
Rushton configuration was compared with a mixed impeller configuration from Scaba with a 20% lower ungassed power draw. The
retrofitted impeller configuration allowed 10% more broth without risking excessive foaming. In this way a substantial increase
in the volumetric productivity of the bioreactor was achieved. Design recommendations for the application of SAFD are given
in this paper. Using these recommendations for the design of a 30,000 l scale bioreactor, almost foamless Escherichia coli fermentations were realised.
Electronic Publication 相似文献
15.
Differential effects of scavenger receptor BI deficiency on lipid metabolism in cells of the arterial wall and in the liver 总被引:13,自引:0,他引:13
Van Eck M Twisk J Hoekstra M Van Rij BT Van der Lans CA Bos IS Kruijt JK Kuipers F Van Berkel TJ 《The Journal of biological chemistry》2003,278(26):23699-23705
Scavenger receptor class B, type I (SRBI) is a key regulator of high density lipoprotein (HDL) metabolism. It facilitates the efflux of cholesterol from cells in peripheral tissues to HDL and mediates the selective uptake of cholesteryl esters from HDL in the liver. We investigated the effects of SRBI deficiency in the arterial wall and in the liver using SRBI-deficient mice and wild-type littermates fed a Western-type diet. The SRBI-deficient mice showed massive accumulation of cholesterol-rich HDL in the circulation, reflecting impaired delivery to the liver. Strikingly, SRBI deficiency did not alter hepatic cholesterol (ester) content nor did it affect the expression of key regulators of hepatic cholesterol homeostasis, including HMG-CoA reductase, the low density lipoprotein receptor, and cholesterol 7alpha-hydroxylase. However, a approximately 40% reduction in biliary cholesterol content was observed, and the expression of ABCG8 and ABCG5, ATP half-transporters implicated in the transport of sterols from the liver to the bile, was attenuated by 70 and 35%, respectively. In contrast to the situation in the liver, SRBI deficiency did result in lipid deposition in the aorta and atherosclerosis. Vascular mRNA analysis showed increased expression of inflammatory markers as well as of genes involved in cellular cholesterol homeostasis. Our data show that, although hepatic cholesterol homeostasis is maintained upon feeding a Western-type diet, SRBI deficiency is associated with de-regulation of cholesterol homeostasis in the arterial wall that results in an increased susceptibility to atherosclerosis. 相似文献
16.
The copolymer of methyl methacrylate (MMA) and 2-[2',3',5'-triiodobenzoyl]oxoethyl methacrylate (1), ratio 3:1 (mass:mass), was prepared via a free-radical polymerization in bulk. The copolymer (M(w) = 97.8 kD and M(n) = 41.5 kD) was dissolved in chloroform and subsequently transformed into beads with a diameter in the micrometer range, using a solvent evaporation technique. The resulting microbeads were characterized by different techniques, including NMR spectroscopy, differential scanning calorimetry, gel permeation chromatography, and scanning electron microscopy. The latter technique was used as the basis for statistical analysis of the bead size. Typically, an average diameter of 96 microm and a standard deviation of 21 microm were obtained. The beads were also subjected to some preliminary tests regarding cytotoxicity. The copolymer of MMA and 1 contains covalently bound iodine. Therefore, the material is intrinsically radiopaque, i.e., capable of absorbing X-radiation while no contrast additive is needed. Our interest in these microspheres stems primarily from their possible utility as injectable and afterward traceable (radiopaque) bulking agents, e.g., for use in urology for the treatment of female stress incontinence due to sphincter deficiency. As a first test into this direction, a sample of the microbeads was mixed with ethylene glycol, and the resulting suspension was studied with respect to injectability and radiopacity. The results suggest that the radiopaque microbeads may provide access to improved bulking agents. Further modification of the surface may be necessary in order to suppress the migratory aptitude of the radiopaque polymeric microspheres in vivo. 相似文献
17.
In a previous paper, we have reported on a new, troglobiticspecies of Georissa and its possible parapatric origin fromGeorissa saulae Benthem-Jutting, 1966, which occurs outsidethe cave system of Batu Sanaron, a limestone outcrop in Sabah,Malaysian Borneo. These analyses were based on genetic and morphometricdata. Here, we formally describe the new species adding anatomicaldata derived from dissections and histological serial sectionsas well as fine structural data of shell, operculum and radula,and compare it with its stem species. The two species differin shell and radular morphology as well as genital characters.Since we found anatomical differences between very closely relatedspecies, we assume that dissections would be of general usefor the taxonomy of Georissa and the remaining nominal genus-grouptaxa of the poorly known Hydrocenidae. 相似文献
18.
Yiying Liu Elzbieta Rzeszutek Menno van der Voort Cheng-Hsuan Wu Even Thoen Ida Skaar Vincent Bulone Pieter C. Dorrestein Jos M. Raaijmakers Irene de Bruijn 《PloS one》2015,10(8)
Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture. 相似文献
19.
Menno Hoekstra Christian A.C. van der Lans Lars Gullestad Pål Aukrust Theo J.C. van Berkel Erik A.L. Biessen 《Biochemical and biophysical research communications》2010,394(3):792-797