Showing papers by "Ghent University published in 2000"
TL;DR: This review describes the state of the art of probiotic research in the culture of fish, crustaceans, mollusks, and live food, with an evaluation of the results obtained so far.
Abstract: There is an urgent need in aquaculture to develop microbial control strategies, since disease outbreaks are recognized as important constraints to aquaculture production and trade and since the development of antibiotic resistance has become a matter of growing concern. One of the alternatives to antimicrobials in disease control could be the use of probiotic bacteria as microbial control agents. This review describes the state of the art of probiotic research in the culture of fish, crustaceans, mollusks, and live food, with an evaluation of the results obtained so far. A new definition of probiotics, also applicable to aquatic environments, is proposed, and a detailed description is given of their possible modes of action, i.e., production of compounds that are inhibitory toward pathogens, competition with harmful microorganisms for nutrients and energy, competition with deleterious species for adhesion sites, enhancement of the immune response of the animal, improvement of water quality, and interaction with phytoplankton. A rationale is proposed for the multistep and multidisciplinary process required for the development of effective and safe probiotics for commercial application in aquaculture. Finally, directions for further research are discussed.
2,072 citations
TL;DR: The authors provide a survey of critical discourse analysis (CDA), a recent school of discourse analysis that concerns itself with relations of power and inequality in language and advocates social commitment and interventionism in research.
Abstract: ▪ Abstract This paper provides a survey of critical discourse analysis (CDA), a recent school of discourse analysis that concerns itself with relations of power and inequality in language. CDA explicitly intends to incorporate social-theoretical insights into discourse analysis and advocates social commitment and interventionism in research. The main programmatic features and domains of enquiry of CDA are discussed, with emphasis on attempts toward theory formation by one of CDA's most prominent scholars, Norman Fairclough. Another section reviews the genesis and disciplinary growth of CDA, mentions some of the recent critical reactions to it, and situates it within the wider picture of a new critical paradigm developing in a number of language-oriented (sub) disciplines. In this critical paradigm, topics such as ideology, inequality, and power figure prominently, and many scholars productively attempt to incorporate social-theoretical insights into the study of language.
2,048 citations
TL;DR: This review discusses the dual action of AOS during plant stress responses, which was first described in pathogenesis but has also recently been demonstrated during several abiotic stress responses.
Abstract: Adaptation to environmental changes is crucial for plant growth and survival. However, the molecular and biochemical mechanisms of adaptation are still poorly understood and the signaling pathways involved remain elusive. Active oxygen species (AOS) have been proposed as a central component of plant adaptation to both biotic and abiotic stresses. Under such conditions, AOS may play two very different roles: exacerbating damage or signaling the activation of defense responses. Such a dual function was first described in pathogenesis but has also recently been demonstrated during several abiotic stress responses. To allow for these different roles, cellular levels of AOS must be tightly controlled. The numerous AOS sources and a complex system of oxidant scavengers provide the flexibility necessary for these functions. This review discusses the dual action of AOS during plant stress responses.
1,815 citations
TL;DR: In this paper, an overview is given of various electronic effects present in polycrystalline thin film solar cells, which do not occur in standard crystalline Si solar cells and how these effects are treated numerically in a numerical solar cell simulation tool, SCAPS.
1,519 citations
TL;DR: Using two mouse models, it is shown that the therapeutic dose of IL-10 can be reduced by localized delivery of a bacterium genetically engineered to secrete the cytokine.
Abstract: The cytokine interleukin-10 (IL-10) has shown promise in clinical trials for treatment of inflammatory bowel disease (IBD). Using two mouse models, we show that the therapeutic dose of IL-10 can be reduced by localized delivery of a bacterium genetically engineered to secrete the cytokine. Intragastric administration of IL-10-secreting Lactococcus lactis caused a 50% reduction in colitis in mice treated with dextran sulfate sodium and prevented the onset of colitis in IL-10(-/-) mice. This approach may lead to better methods for cost-effective and long-term management of IBD in humans.
1,398 citations
TL;DR: The role of L-AA in metabolism and the latest studies regarding its bio- synthesis, tissue compartmentalisation, turnover and catabolism are focused on, as well as the potential to improve the L- AA content of crops.
Abstract: Humans are unable to synthesise L-ascorbic acid (L-AA, ascorbate, vitamin C), and are thus entirely dependent upon dietary sources to meet needs. In both plant and animal metabolism, the biological functions of L-ascorbic acid are centred around the antioxidant properties of this molecule. Considerable evidence has been accruing in the last two decades of the importance of L-AA in protecting not only the plant from oxidative stress, but also mammals from various chronic diseases that have their origins in oxidative stress. Evidence suggests that the plasma levels of L-AA in large sections of the population are sub-optimal for the health protective effects of this vitamin. Until quite recently, little focus has been given to improving the L-AA content of plant foods, either in terms of the amounts present in commercial crop varieties, or in minimising losses prior to ingestion. Further, while L-AA biosynthesis in animals was elucidated in the 1960s, 1 it is only very recently that a distinct biosynthetic route for plants has been proposed. 2 The characterisation of this new pathway will undoubtedly provide the necessary focus and impetus to enable fundamental questions on plant L-AA metabolism to be resolved. This review focuses on the role of L-AA in metabolism and the latest studies regarding its bio- synthesis, tissue compartmentalisation, turnover and catabolism. These inter-relationships are considered in relation to the potential to improve the L-AA content of crops. Methodology for the reliable analysis of L-AA in plant foods is briefly reviewed. The concentrations found in common food sources and the effects of processing, or storage prior to consumption are discussed. Finally the factors that determine the bioavailability of L-AA and how it may be improved are considered, as well as the most important future research needs. # 2000 Society of Chemical Industry
1,279 citations
TL;DR: Correcting the principal mediators of hyperglycaemia‐induced endothelial dysfunction may be activation of protein kinase C, increased activity of the polyol pathway, non‐enzymatic glycation and oxidative stress, as well as administration of ACE inhibitors and folate has been shown to improve endothelium‐dependent vasodilation in diabetes.
Abstract: Endothelial dysfunction plays a key role in the pathogenesis of diabetic vascular disease. The endothelium controls the tone of the underlying vascular smooth muscle through the production of vasodilator mediators. The endothelium-derived relaxing factors (EDRF) comprise nitric oxide (NO), prostacyclin, and a still elusive endothelium-derived hyperpolarizing factor (EDHF). Impaired endothelium-dependent vasodilation has been demonstrated in various vascular beds of different animal models of diabetes and in humans with type 1 and 2 diabetes. Several mechanisms of endothelial dysfunction have been reported, including impaired signal transduction or substrate availibility, impaired release of EDRF, increased destruction of EDRF, enhanced release of endothelium-derived constricting factors and decreased sensitivity of the vascular smooth muscle to EDRF. The principal mediators of hyperglycaemia-induced endothelial dysfunction may be activation of protein kinase C, increased activity of the polyol pathway, non-enzymatic glycation and oxidative stress. Correction of these pathways, as well as administration of ACE inhibitors and folate, has been shown to improve endothelium-dependent vasodilation in diabetes. Since the mechanisms of endothelial dysfunction appear to differ according to the diabetic model and the vascular bed under study, it is important to select clinically relevant models for future research of endothelial dysfunction.
1,148 citations
TL;DR: The results indicate that the rheological properties of the gelatin-based hydrogels can be controlled by the degree of substitution, polymer concentration, initiator concentration, and UV irradiation conditions.
1,036 citations
TL;DR: This papermarizes recent physicochemical and biological information on polyplexes and aims to provide new insights with respect to thistype of gene delivery system and describes the in vitro and in vivo genetransfection behavior of polyplexe.
Abstract: Gene transfer to humans requires carriers for the plasmid DNA which can efficiently and safely carry the gene into the nucleus of the desired cells. A series of chemically different cationic polymers are currently being investigated for these purposes. Although many cationic polymers indeed condense DNA spontaneously, which is a requirement for gene transfer in most types of cells, the physicochemical and biopharmaceutical behavior of the current generation of polyplexes severely limits an efficient gene transfer in vitro and especially in vivo. This paper summarizes recent physicochemical and biological information on polyplexes and aims to provide new insights with respect to this type of gene delivery system. Firstly, the chemical structure of frequently studied cationic polymers is represented. Secondly, the parameters influencing condensation of DNA by cationic polymers are described. Thirdly, the surface properties, solubility, aggregration behavior, degradation and dissociation of polyplexes are considered. The review ends by describing the in vitro and in vivo gene transfection behavior of polyplexes.
910 citations
TL;DR: In this paper, the authors defined definitions of concepts related to speciation of elements, more particularly speciation analysis and chemical species, and proposed a categorization of species according to isotopic composition of the element, its oxidation and electronic states, and its complex and molecular structure.
Abstract: This paper presents definitions of concepts related to speciation of elements, more particularly speciation analysis and chemical species Fractionation is distinguished from speciation analysis, and a general outline of fractionation procedures is given We propose a categorization of species according to isotopic composition of the element, its oxidation and electronic states, and its complex and molecular structure Examples are given of methodological approaches used for speciation analysis A synopsis of the methodology of dynamic speciation analysis is also presented
852 citations
TL;DR: In this paper, a phylogenetic analysis of the cadherin superfamily is presented, which can be distinguished on the basis of protein domain composition, genomic structure, and phylogenetic analyses of the protein sequences.
TL;DR: A central role for microphytobenthos in moderating carbon flow in coastal sediments is indicated, and C-13 assimilation increased until day 3, and carbon isotope analysis of polar lipid derived fatty acids specific for bacteria showed rapid, significant transfer from benthic algae to bacteria.
Abstract: At two intertidal sites (one sandy and one silty, in the Scheldt estuary, The Netherlands), the fate of microphytobenthos was studied through an in situ C-13 pulse- chase experiment. Label was added at the beginning of low tide, and uptake of C-13 by algae was linear during the whole period of tidal exposure (about 27 mg m(-2) h(-1) in the top millimeter at both sites). The C-13 fixed by microphytobenthos was rapidly displaced toward deeper sediment layers (down to 6 cm), in particular at the dynamic, sandy site. The residence times of microphytobenthos with respect to external losses (resuspension and respiration) were about 2.4 and 5.6 d at the sandy and silly stations, respectively. The transfer of carbon from microphytobenthos to benthic consumers was estimated from the appearance of C-13 in bacterial biomarkers, handpicked nematodes, and macrofauna. The incorporation of C-13 into bacterial biomass was quantified by carbon isotope analysis of polar lipid derived fatty acids specific for bacteria. The bacterial polar lipid-derived fatty acids (i14:0, i15:0, a15:0, i16:0, and 18:1 omega 7c) showed rapid, significant transfer from benthic algae to bacteria with maximum labeling after 1 d. Nematodes became enriched after 1 h, and C-13 assimilation increased until day 3. Microphytobenthos carbon entered all heterotrophic components in proportion to heterotrophic biomass distribution (bacteria > macrofauna > meiofauna). Our results indicate a central role for microphytobenthos in moderating carbon flow in coastal sediments. [KEYWORDS: Water marine habitats; microbenthic communities; westerschelde estuary; microbial biomass; epipelic diatoms; ecological role; organic-matter; grazing rates; chlorophyll-a; secret garden]
TL;DR: A decade-scale reconstruction of rainfall and drought in equatorial east Africa over the past 1,100 years is presented, based on lake-level and salinity fluctuations of Lake Naivasha inferred from three different palaeolimnological proxies: sediment stratigraphy and the species compositions of fossil diatom and midge assemblages.
Abstract: Knowledge of natural long-term rainfall variability is essential for water-resource and land-use management in sub-humid regions of the world In tropical Africa, data relevant to determining this variability are scarce because of the lack of long instrumental climate records and the limited potential of standard high-resolution proxy records such as tree rings and ice cores Here we present a decade-scale reconstruction of rainfall and drought in equatorial east Africa over the past 1,100 years, based on lake-level and salinity fluctuations of Lake Naivasha (Kenya) inferred from three different palaeolimnological proxies: sediment stratigraphy and the species compositions of fossil diatom and midge assemblages Our data indicate that, over the past millennium, equatorial east Africa has alternated between contrasting climate conditions, with significantly drier climate than today during the 'Medieval Warm Period' (approximately AD 1000-1270) and a relatively wet climate during the 'Little Ice Age' (approximately AD 1270-1850) which was interrupted by three prolonged dry episodes We also find strong chronological links between the reconstructed history of natural long-term rainfall variation and the pre-colonial cultural history of east Africa, highlighting the importance of a detailed knowledge of natural long-term rainfall fluctuations for sustainable socio-economic development
TL;DR: It is demonstrated that the closely related acetyltransferases p300 and CBP potentiate β‐catenin‐mediated activation of the siamois promoter, a known Wnt target, and synergize to stimulate a synthetic reporter gene construct.
Abstract: Wnt growth factors regulate a variety of developmental processes by altering specific gene expression patterns. In vertebrates β-catenin acts as transcriptional activator, which is needed to overcome target gene repression by Groucho/TLE proteins, and to permit promoter activation as the final consequence of Wnt signaling. However, the molecular mechanisms of transcriptional activation by β-catenin are only poorly understood. Here we demonstrate that the closely related acetyltransferases p300 and CBP potentiate β-catenin-mediated activation of the siamois promoter, a known Wnt target. β-catenin and p300 also synergize to stimulate a synthetic reporter gene construct, whereas activation of the cyclin D1 promoter by β-catenin is refractory to p300 stimulation. Axis formation and activation of the β-catenin target genes siamois and Xnr-3 in Xenopus embryos are sensitive to the E1A oncoprotein, a known inhibitor of p300/CBP. The C-terminus of β-catenin interacts directly with a region overlapping the CH-3 domain of p300. p300 could participate in alleviating promoter repression imposed by chromatin structure and in recruiting the basal transcription machinery to promoters of particular Wnt target genes.
TL;DR: The latter four parameters play a dominant role in the genesis of anterior knee pain and are deemed to be risk factors for this syndrome.
Abstract: Many variables have retrospectively been associated with the presence of anterior knee pain. Very few prospective data exist, however, to determine which of these variables will lead to the development of anterior knee pain. It was our purpose in this study to determine the intrinsic risk factors for the development of anterior knee pain in an athletic population over a 2-year period. Before the start of training, 282 male and female students enrolled in physical education classes were evaluated for anthropometric variables, motor performance, general joint laxity, lower leg alignment characteristics, muscle length and strength, static and dynamic patellofemoral characteristics, and psychological parameters. During this 2-year follow-up study, 24 of the 282 students developed patellofemoral pain. Statistical analyses revealed a significant difference between those subjects who developed patellofemoral pain and those who did not concerning quadriceps and gastrocnemius muscle flexibility, explosive strength, thumb-forearm mobility, reflex response time of the vastus medialis obliquus and vastus lateralis muscles, and the psychological parameter of seeking social support. However, only a shortened quadriceps muscle, an altered vastus medialis obliquus muscle reflex response time, a decreased explosive strength, and a hypermobile patella had a significant correlation with the incidence of patellofemoral pain. We concluded that the latter four parameters play a dominant role in the genesis of anterior knee pain and we therefore deem them to be risk factors for this syndrome.
TL;DR: A comparative study between unoperated CLBP patients and matched control subjects with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels showed that only the CSA of the multifidus and only at the lowest level was found to be statistically smaller in LBP patients.
Abstract: Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP.
TL;DR: Despite the high polymorphic value of the AFLP markers, standard statistical tests could not differentiate between two gene pools derived from different breeding programmes, and it proved also impossible to correlate fodder and turf phenotypes with AFLP distance data.
Abstract: An evaluation was performed of the potential use of AFLP markers to reveal polymorphisms among Lolium perenne plants with different degrees of kinship. Radioactive and fluorescent detection techniques were applied. The use of a fluorescent detection approach contributed greatly to the speed and ease of conducting and interpreting the AFLP patterns. The great discriminative power of AFLP markers and their capacity to represent genetic relationships among ryegrass plants was shown. Despite the high polymorphic value of the AFLP markers, standard statistical tests could not differentiate between two gene pools derived from different breeding programmes. It proved also impossible to correlate fodder and turf phenotypes with AFLP distance data. A very important point revealed by our data is the high degree of genetic diversity within commercial ryegrass varieties. Our findings are relevant to any outcrossing crop with a breeding strategy based on the production of synthetic populations.
TL;DR: It is shown that the G1-to-S phase transition requires an adequate level of GSH, which suggests the existence of a GSH-dependent developmental pathway essential for initiation and maintenance of cell division during postembryonic root development.
Abstract: Activation of cell division in the root apical meristem after germination is essential for postembryonic root development. Arabidopsis plants homozygous for a mutation in the ROOT MERISTEMLESS1 (RML1) gene are unable to establish an active postembryonic meristem in the root apex. This mutation abolishes cell division in the root but not in the shoot. We report the molecular cloning of the RML1 gene, which encodes the first enzyme of glutathione (GSH) biosynthesis, γ-glutamylcysteine synthetase, and which is allelic to CADMIUM SENSITIVE2. The phenotype of the rml1 mutant, which was also evident in the roots of wild-type Arabidopsis and tobacco treated with an inhibitor of GSH biosynthesis, could be relieved by applying GSH to rml1 seedlings. By using a synchronized tobacco cell suspension culture, we showed that the G1-to-S phase transition requires an adequate level of GSH. These observations suggest the existence of a GSH-dependent developmental pathway essential for initiation and maintenance of cell division during postembryonic root development.
TL;DR: This study investigated spatio-temporal variables, ground reaction forces and sagittal and frontal plane kinematics during the stance phase of nine trained subjects running barefoot and shod at three different velocities to find sagittal kinematic adaptations between conditions.
TL;DR: This work offers a sustained exploration of modules from developmental and evolutionary perspectives, and discusses what modularity is, how it can be identified and modeled,How it originated and evolved, and why it matters.
Abstract: This work offers a sustained exploration of modules from developmental and evolutionary perspectives. Contributors discuss what modularity is, how it can be identified and modeled, how it originated and evolved, and why it matters.
TL;DR: The vocal quality of a patient is modeled by means of a Dysphonia Severity Index (DSI), which is designed to establish an objective and quantitative correlate of the perceived vocal quality.
Abstract: The vocal quality of a patient is modeled by means of a Dysphonia Severity Index (DSI), which is designed to establish an objective and quantitative correlate of the perceived vocal quality The DSI is based on the weighted combination of the following selected set of voice measurements: highest Frequency (F-0-High in Hz), lowest intensity (I-Low in dB), maximum phonation time (Mm in s), and jitter (%). The DSI is derived from a multivariate analysis of 387 subjects with the goal of describing, purely based on objective measures, the perceived voice quality It is constructed as DSI = 0.13 x MPT + 0.0053 x F-0-High - 0.26 x I-Low - 1.18 x Jitter (%)+ 12.4. The DSI For perceptually normal voices equals +5 and for severely dysphonic voices -5. The more negative the patient's index, the worse is his or her vocal quality As such, the DSI is especially useful to evaluate therapeutic evolution of dysphonic patients. Additionally, there is a high correlation between the DSI and the Voice Handicap Index score.
TL;DR: An epidemiological study of risk factors for postpartal ovarian disturbances was carried out on 334 high-yielding dairy cows in 6 well-managed Belgian herds and attention was focused on abnormal cyclicity during the preservice, postpartum period.
TL;DR: Analysis of the recA gene of the Burkholderia cepacia complex provides a rapid and robust nucleotide sequence-based approach to identify and classify this taxonomically complex group of opportunistic pathogens.
Abstract: Bacteria of the Burkholderia cepacia complex consist of five discrete genomic species, including genomovars I and III and three new species: Burkholderia multivorans (formerly genomovar II), Burkholderia stabilis (formerly genomovar IV), and Burkholderia vietnamiensis (formerly genomovar V). Strains of all five genomovars are capable of causing opportunistic human infection, and microbiological identification of these closely related species is difficult. The 16S rRNA gene (16S rDNA) and recA gene of these bacteria were examined in order to develop rapid tests for genomovar identification. Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified 16S rDNA revealed sequence polymorphisms capable of identifying B. multivorans and B. vietnamiensis but insufficient to discriminate strains of B. cepacia genomovars I and III and B. stabilis. RFLP analysis of PCR-amplified recA demonstrated sufficient nucleotide sequence variation to enable separation of strains of all five B. cepacia complex genomovars. Complete recA nucleotide sequences were obtained for 20 strains representative of the diversity of the B. cepacia complex. Construction of a recA phylogenetic tree identified six distinct clusters (recA groups): B. multivorans, B. vietnamiensis, B. stabilis, genomovar I, and the subdivision of genomovar III isolates into two recA groups, III-A and III-B. Alignment of recA sequences enabled the design of PCR primers for the specific detection of each of the six latter recA groups. The recA gene was found on the largest chromosome within the genome of B. cepacia complex strains and, in contrast to the findings of a previous study, only a single copy of the gene was present. In conclusion, analysis of the recA gene of the B. cepacia complex provides a rapid and robust nucleotide sequence-based approach to identify and classify this taxonomically complex group of opportunistic pathogens.
TL;DR: In this paper, the authors discuss the complex interaction of different processes which transform landscapes formed by rural life styles into urban like ones, and the existing cities and urban network form the framework for this change, which is affecting increasingly larger areas in the countryside.
Abstract: Urbanization refers to the complex interaction of different processes which transform landscapes formed by rural life styles into urban like ones. Urbanization causes profound changes in the ecological functioning of the landscape and gradually results in a changing spatial structure, i.e. forms new landscape patterns. The existing cities and urban network form the framework for this change, which is affecting increasingly larger areas in the countryside. Urbanization is mainly studied from social and economical viewpoints. Urban planners think about optimization of the land use and about aesthetics when reshaping the environment. Landscape ecology is lacking in urban planning because of different goals and concepts, but mostly because of missing significant information about these highly dynamical landscapes.
TL;DR: In this article, the relationship between Cloninger's Temperament and Character dimensions and the Five-Factor Model (FFM) of personality is investigated in a randomised sample of 130 patients admitted to the Emergency Psychiatric Unit of a large university hospital.
TL;DR: Evidence is provided to support the hypothesis that the aquaculture and human compartments of the environment behave as a single interactive compartment and that related tetracycline resistance-encoding plasmids have disseminated between differentAeromonas species and E. coli and between the human and Aquaculture environments in distinct geographical locations.
Abstract: Oxytetracycline-resistant (OT(r)) mesophilic aeromonads were recovered from untreated hospital effluent (72 isolates) and from fish farm hatchery tanks (91 isolates) at sites within the English Lake District, Cumbria, England. The transfer of OT(r) plasmids from these isolates was investigated. Using Escherichia coli J53-1 as a recipient, 11 isolates from the hospital site and 6 isolates from the fish farm site transferred OT(r) plasmids (designated pFBAOT1 to 17). Original isolates were identified using fatty acid methyl ester and fluorescent amplified fragment length polymorphism comparisons as either Aeromonas hydrophila HG3 (eight isolates), A. veronii b.v. sobria HG8 (six isolates), and A. caviae HGB5 (one isolate). One isolate remained unidentified, and one could not be assigned a taxonomic designation beyond the genus level. Plasmids pFBAOT1 to -17 were screened for the presence of the tetracycline resistance determinants Tet A to E and Tet G. Only determinant Tet A (10 plasmids) was detected in these plasmids, with 7 tet gene determinants remaining unclassified. In all cases, Tet A was located on a 5.5-kb EcoRI restriction fragment. Hybridization with inc-rep probes N, P, Q, W, and U showed pFBAOT3, -4, -5, -6, -7, -9, and -11, from the hospital environment, to be IncU plasmids. Further, restriction fragment length polymorphism (RFLP) analyses and DNA probing demonstrated that pFBAOT plasmids were closely related to IncU OT(r) plasmids pASOT, pASOT2, pASOT3, pRAS1 (originally isolated from A. salmonicida strains from fish farms in Scotland and Norway, respectively), and pIE420 (isolated from a German hospital E. coli strain). In addition, DNA analyses demonstrated that plasmids pRAS1 and pIE420 had identical RFLP profiles and that all fragments hybridized to each other. The presence of tetracycline resistance transposon Tn1721 in its entirety or in a truncated form in these plasmids was demonstrated. These results provided direct evidence that related tetracycline resistance-encoding plasmids have disseminated between different Aeromonas species and E. coli and between the human and aquaculture environments in distinct geographical locations. Collectively, these findings provide evidence to support the hypothesis that the aquaculture and human compartments of the environment behave as a single interactive compartment.
TL;DR: In this paper, a conceptual framework that integrates the major determinants of consumer reactions to stock-outs is presented, and the framework can be empirically implemented, allowing retailers and manufacturers to determine how much each factor contributes to stock out losses.
TL;DR: The retina receives its nutrients from two separate circulations: retinal and choroidal circulation, which are characterized by a low blood flow while flow in the choroid is high.
Abstract: The retina receives its nutrients from two separate circulations: retinal and choroidal circulation. This short overview describes the determinants in the regulation of these circulations. Retinal circulation is characterized by a low blood flow while flow in the choroid is high. The choroidal circulation is mainly controlled by sympathetic innervation and is not autoregulated. Retinal circulation lacks autonomic innervation, shows an efficient autoregulation and is mainly influenced by local factors. Local mediators released by endothelial cells and surrounding retinal tissue also have a substantial role in the regulation of retinal circulation.
TL;DR: The results indicate that bioaugmentation, even with a strain originating from that ecosystem and able to effectively grow on a selective substrate, is not permanent and will probably require regular resupplementation.
Abstract: A strain identified as Comamonas testosteroni I2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-CA). During the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. This strain was tested for its ability to clean wastewater containing 3-CA upon inoculation into activated sludge. To monitor its survival, the strain was chromosomally marked with the gfp gene and designated I2gfp. After inoculation into a lab-scale semicontinuous activated-sludge (SCAS) system, the inoculated strain maintained itself in the sludge for at least 45 days and was present in the sludge flocs. After an initial adaptation period of 6 days, complete degradation of 3-CA was obtained during 2 weeks, while no degradation at all occurred in the noninoculated control reactor. Upon further operation of the SCAS system, only 50% 3-CA removal was observed. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes revealed a dynamic change in the microbial community structure of the activated sludge. The DGGE patterns of the noninoculated and the inoculated reactors evolved after 7 days to different clusters, which suggests an effect of strain inoculation on the microbial community structure. The results indicate that bioaugmentation, even with a strain originating from that ecosystem and able to effectively grow on a selective substrate, is not permanent and will probably require regular resupplementation.
TL;DR: In this article, the authors present an integrated approach based on holism, perception and evolution for landscape research, which explains the interaction between structure and functioning and the importance of the scale.