998 resultados para clonal plants


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The in-line measurement of COD and NH4-N in the WWTP inflow is crucial for the timely monitoring of biological wastewater treatment processes and for the development of advanced control strategies for optimized WWTP operation. As a direct measurement of COD and NH4-N requires expensive and high maintenance in-line probes or analyzers, an approach estimating COD and NH4-N based on standard and spectroscopic in-line inflow measurement systems using Machine Learning Techniques is presented in this paper. The results show that COD estimation using Radom Forest Regression with a normalized MSE of 0.3, which is sufficiently accurate for practical applications, can be achieved using only standard in-line measurements. In the case of NH4-N, a good estimation using Partial Least Squares Regression with a normalized MSE of 0.16 is only possible based on a combination of standard and spectroscopic in-line measurements. Furthermore, the comparison of regression and classification methods shows that both methods perform equally well in most cases.

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Pseudomonas aeruginosa is associated with infectious endometritis in horses. Although infectious endometritis is often considered a venereal infection, there is relatively limited genotypic-based evidence to support this mode of transmission. The study sought to determine the relatedness between genital P. aeruginosa isolates collected from a limited geographical region using molecular strain typing. Enterobacterial repetitive intergenic consensus PCR typing was performed on 93 isolates collected between 2005 and 2009 from 2058 thoroughbred horses (including 18 stallions) at 66 studs. While P. aeruginosa was not detected in the stallions, 53/93 (57%) mares harbouring P. aeruginosa had clonally related strains, which included a single dominant genotype detected in 42 (45%) mares from 13 different studs. These novel findings suggest that most equine genital P. aeruginosa infections in this region may have been acquired from mechanisms other than direct horse to horse transmission. Instead, other potential acquisition pathways, as well as strain specific adaptation to the equine genital tract, should be investigated.

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Pseudomonas aeruginosa genotyping relies mainly upon DNA fingerprinting methods, which can be subjective, expensive and time-consuming. The detection of at least three different clonal P. aeruginosa strains in patients attending two cystic fibrosis (CF) centres in a single Australian city prompted the design of a non-gel-based PCR method to enable clinical microbiology laboratories to readily identify these clonal strains. We designed a detection method utilizing heat-denatured P. aeruginosa isolates and a ten-single-nucleotide polymorphism (SNP) profile. Strain differences were detected by SYBR Green-based real-time PCR and high-resolution melting curve analysis (HRM10SNP assay). Overall, 106 P. aeruginosa sputum isolates collected from 74 patients with CF, as well as five reference strains, were analysed with the HRM10SNP assay, and the results were compared with those obtained by pulsed-field gel electrophoresis (PFGE). The HRM10SNP assay accurately identified all 45 isolates as members of one of the three major clonal strains characterized by PFGE in two Brisbane CF centres (Australian epidemic strain-1, Australian epidemic strain-2 and P42) from 61 other P. aeruginosa strains from Australian CF patients and two representative overseas epidemic strain isolates. The HRM10SNP method is simple, is relatively inexpensive and can be completed in <3 h. In our setting, it could be made easily available for clinical microbiology laboratories to screen for local P. aeruginosa strains and to guide infection control policies. Further studies are needed to determine whether the HRM10SNP assay can also be modified to detect additional clonal strains that are prevalent in other CF centres.

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The invasive aquatic plant species Elodea nuttallii could pose a considerable risk to European freshwater ecosystems based on its current distribution, rate of spread and potential for high biomass. However, little research has been conducted on the impacts of this species on native biota. This study takes an ecosystem-wide approach and examines the impact of E. nuttallii on selected physicochemical parameters (dissolved oxygen and pH), algae, invertebrate and macrophyte communities. Elodea nuttallii had small but significant impacts on plant, invertebrate and algal species. The richness of algal periphyton was lower on E. nuttallii than on native macrophytes. The taxonomic composition of invertebrate communities associated with E. nuttallii differed from that associated with similar native plant species, but did not differ in terms of total biomass or species richness. Macrophyte species richness and total cover were positively correlated with percentage cover of E. nuttallii. Not all macrophyte species responded in the same way to E. nuttallii invasion; cover of the low-growing species, Elodea canadensis and charophytes were negatively correlated with E. nuttallii cover, whilst floating-rooted plants were positively correlated with E. nuttallii cover. All observed differences in the macrophyte community were small relative to other factors such as nutrient levels, inter-annual variation and differences between sites. Despite this, the observed negative association between E. nuttallii and charophytes is a key concern due to the rarity and endangered status of many charophyte species.

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Ethnopharmacological relevance
The two plants investigated here (Fagonia cretica L. and Hedera nepalensis K. Koch) have been previously reported as natural folk medicines for the treatment of diabetes but until now no scientific investigation of potential anti-diabetic effects has been reported. 


Materials and methods
In vitro inhibitory effect of the two tested plants and their five isolated compounds on the dipeptidyl peptidase 4 (DPP-4) was studied for the assessment of anti-diabetic activity. 

Results
A crude extract of Fagonia cretica possessed good inhibitory activity (IC50value: 38.1 μg/ml) which was also present in its n-hexane (FCN), ethyl acetate (FCE) or aqueous (FCA) fractions. A crude extract of Hedera nepalensis (HNC) possessed even higher inhibitory activity (IC50value: 17.2 μg/ml) and this activity was largely retained when further fractionated in either ethyl acetate (HNE; IC50: 34.4 μg/ml) or n-hexane (HNN; 34.2 μg/ml). Bioactivity guided isolation led to the identification of four known compounds (isolated for the first time) from Fagonia cretica: quinovic acid (1), quinovic acid-3β-O-β-d-glycopyranoside (2), quinovic acid-3β-O-β-d-glucopyranosyl-(28→1)-β-d-glucopyranosyl ester (3), and stigmasterol (4) all of which inhibited DPP-4 activity (IC50: 30.7, 57.9, 23.5 and >100 μM, respectively). The fifth DPP-4 inhibitor, the triterpenoid lupeol (5) was identified in Hedera nepalensis (IC50: 31.6 μM). 

Conclusion
The experimental study revealed that Fagonia cretica and Hedera nepalensis contain compounds with significant DPP-4 inhibitory activity which should be further investigated for their anti-diabetic potential.

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Monoglycated cholecystokinin octapeptide (Asp(1)-glucitol CCK-X) was prepared under hyperglycaemic reducing conditions and purified by reverse phase-high performance liquid chromatography. Electrospray ionisation mass spectrometry and automated Edman degradation demonstrated that CCK-8 was glycated specifically at the amino-terminal Asp(1) residue. Effects of Asp(1)-glucitol CCK-8 and CCK-8 on insulin secretion were examined using glucose-responsive clonal BRIN-BD11 cells. In acute (20 min) incubations, 10(-10) mol/l CCK-8 enhanced insulin release by 1.2-1.5-fold at 5.6-11.1 mmol/l glucose. The stimulatory effect induced by 10(-10) mom CCK-8 was abolished following glycation. At 5.6 mmol/l glucose, CCK-8 at concentrations ranging from 10(-11) to 10(-7) mol/l induced a significant 1.6-1.9-fold increase in insulin secretion. Insulin output in the presence of Asp(1)-glucitol CCK-8 over the concentration range 10(-11)-10(-7) mol/l was decreased by 21-35% compared with CCK-8, and its insulinotropic action was effectively abolished. Asp(1)-glucitol CCK-8 at 10(-8) mol/l also completely blocked the stimulatory effects of 10(-11)-10(-8) mol/l CCK-8. These data indicate that structural modification by glycation at the amino-terminal Asp(1) residue effectively abolishes and/or antagonises the insulinotropic activity of CCK-8. (C) 1999 Elsevier Science B.V. All rights reserved.

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Dynamic economic load dispatch (DELD) is one of the most important steps in power system operation. Various optimisation algorithms for solving the problem have been developed; however, due to the non-convex characteristics and large dimensionality of the problem, it is necessary to explore new methods to further improve the dispatch results and minimise the costs. This article proposes a hybrid differential evolution (DE) algorithm, namely clonal selection-based differential evolution (CSDE), to solve the problem. CSDE is an artificial intelligence technique that can be applied to complex optimisation problems which are for example nonlinear, large scale, non-convex and discontinuous. This hybrid algorithm combines the clonal selection algorithm (CSA) as the local search technique to update the best individual in the population, which enhances the diversity of the solutions and prevents premature convergence in DE. Furthermore, we investigate four mutation operations which are used in CSA as the hyper-mutation operations. Finally, an efficient solution repair method is designed for DELD to satisfy the complicated equality and inequality constraints of the power system to guarantee the feasibility of the solutions. Two benchmark power systems are used to evaluate the performance of the proposed method. The experimental results show that the proposed CSDE/best/1 approach significantly outperforms nine other variants of CSDE and DE, as well as most other published methods, in terms of the quality of the solution and the convergence characteristics.

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Burkholderia cenocepacia causes opportunistic infections in plants, insects, animals, and humans, suggesting that “virulence” depends on the host and its innate susceptibility to infection. We hypothesized that modifications in key bacterial molecules recognized by the innate immune system modulate host responses to B. cenocepacia. Indeed, modification of lipo- polysaccharide (LPS) with 4-amino-4-deoxy-L-arabinose and flagellin glycosylation attenuates B. cenocepacia infection in Arabi- dopsis thaliana and Galleria mellonella insect larvae. However, B. cenocepacia LPS and flagellin triggered rapid bursts of nitric oxide and reactive oxygen species in A. thaliana leading to activation of the PR-1 defense gene. These responses were drastically reduced in plants with fls2 (flagellin FLS2 host receptor kinase), Atnoa1 (nitric oxide-associated protein 1), and dnd1-1 (reduced production of nitric oxide) null mutations. Together, our results indicate that LPS modification and flagellin glycosylation do not affect recognition by plant receptors but are required for bacteria to establish overt infection.

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Perennial rye-grass was subjected to two different14C labelling regimes to enable a partitioning of the carbon sources contributing to rhizosphere carbon-flow. Plant/soil microcosms were designed which enabled rye-grass plants to either receive a single pulse of14C-CO2 or to be pre-labelled using a series of14C-CO2 pulses, allowing the fate of newly photoassimilated carbon and carbon lost by root decomposition to be followed into the soil. For young rye-grass plants grown over a short period, rhizosphere carbon flow was found to be dominated by newly photoassimilated carbon. Evidence for this came from the observed percentage of the total14C budget (i.e. total14C-CO2 fixed by the plants) lost from the root/soil system, which was 30 times greater for the pulse labelled compared to pre-labelled plants. Root decomposition was found to be less at 10°C compared to 20-25°C, though input of14C into the soil was the same at both temperatures. © 1988 Kluwer Academic Publishers.

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Prominent theories of plant defence have predicted that plants growing on nutrient-poor soils produce more phenolic defence compounds than those on richer soils. Only recently has the Protein Competition Model (PCM) of phenolic allocation suggested that N and P limitation could have different effects because the nutrients are involved in different cellular metabolic processes. 2. We extend the prediction of the PCM and hypothesize that N will have a greater influence on the production of phenolic defensive compounds than P availability, because N limitation reduces protein production and thus competition for phenylalanine, a precursor of many phenolic compounds. In contrast, P acts as a recyclable cofactor in these reactions, allowing protein and hence phenolic production to continue under low P conditions. 3. We test this hypothesis by comparing the foliar concentrations of phenolic compounds in (i) phenotypes of 21 species growing on P-rich alluvial terraces and P-depleted marine terraces in southern New Zealand, and (ii) 87 species growing under similar climates on comparatively P-rich soils in New Zealand vs. P-depleted soils in Tasmania. 4. Foliar P concentrations of plants from the marine terraces were about half those of plants from alluvial soils, and much lower in Tasmania than in New Zealand. However, foliar concentrations of N and phenolic compounds were similar across sites in both comparisons, supporting the hypothesis that N availability is a more important determinant of plant investment in phenolic defensive compounds than P availability. We found no indication that reduced soil P levels influenced plant concentrations of phenolic compounds. There was wide variation in the foliar N and P concentrations among species, and those with low foliar nutrient concentrations produced more phenolics (including condensed tannins). 5. Our study is the first trait comparison extending beyond standard leaf economics to include secondary metabolites related to defence in forest plants, and emphasizes that N and P have different influences on the production of phenolic defence compounds. © 2009 British Ecological Society.

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The genus Bursaphelenchus includes B. xylophilus (Steiner et Buhrer, 1934) Nickle, 1981, which is of world economic and quarantine importance. Distinction among several species of the pinewood nematodes species complex (PWNSC) is often difficult. Besides standard morphology, morphometrics and molecular biology, new tools are welcome to better understand this group. The computerized (or e-) key of this genus, presented in this communication, includes 74 species (complete list of valid species of the world fauna) and 35 characters, that were used by the taxonomic experts of this group, in the original descriptions. Morphology of sex organs (male spicules and female vulval region) was digitized and classified to distinguish alternative types. Several qualitative characters with overlapping character states (expressions) were transformed into the morphometric indices with the discontinuous ranges (characters of ratios of the spicule dimensions). Characters and their states (expressions) were illustrated in detail and supplied by brief user-friendly comments. E-key was created in the BIKEY identification system (Dianov & Lobanov, 1996-2004). The system has built-algorithm ranging characters depending on their diagnostic values at each step of identification. Matrix of species and the character states (structural part of the e-key database) may be easily transformed using statistical packages into the dendrograms of general phenetic similarities (UPGMA, standard distance: mean character difference). It may be useful in the detailed analysis of taxonomy and evolution of the genus and in its splitting to the species groups based on morphology. The verification of the dendrogram using the information on the species links with insect vectors and their associated plants, provided an opportunity to recognize the five clusters (xylophilus, hunti, eremus sensu stricto, tusciae and piniperdae sensu stricto), which seem to be the natural species groups. The hypothesis about the origin and the first stages of the genus evolution is proposed. A general review of the genus Bursaphelenchus is presented.

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No presente trabalho desenvolveram-se estudos visando a valorização do coberto vegetal da Ilha de Porto Santo, através de duas metodologias de investigação complementares: a) preservação e reintrodução na Ilha de uma espécie endémica e em risco do Arquipélago da Madeira (Olea maderensis) e de uma espécie naturalizada (Olea europaea ssp. europaea var. sylvestris), recorrendo para o efeito a técnicas de biotecnologia (micropropagação); b) análise da percepção da comunidade local e visitante sobre o fenómeno da desertificação e a valorização do coberto vegetal bem como a sua aceitação relativamente à aplicação de técnicas de biotecnologia (para micropropagar e reintroduzir espécies de oliveira na Ilha) para minimização do processo de desertificação. A dissertação estrutura-se em quatro partes principais. A Parte I caracteriza a Ilha de Porto Santo em termos geográficos, geológicos, climáticos, sócio-economicos e do uso do solo. Enquadra, ainda, o problema da desertificação, através da caracterização/evolução do coberto vegetal ao longo dos anos. Finalmente apresentam-se os objectivos gerais deste estudo. A Parte II centra-se no desenvolvimento de metodologias no âmbito da biotecnologia vegetal para propagação de espécies de O. maderensis e O. europaea ssp. europaea var. sylvestris. em larga escala. Esta parte está dividida em seis capítulos. O Capítulo II.1 aborda a distribuição geográfica das espécies de oliveira e faz uma revisão bibliográfica dos aspectos mais importantes da micropropagação de oliveira (O. europaea L.), principalmente através da micropropagação por estimulação de gomos axilares. No final deste capítulo apresentam-se os objectivos específicos desta investigação. No Capítulo II.2 faz-se a caracterização genética de genótipos de O. maderensis do Arquipélago da Madeira através da análise da ploidia e do conteúdo em DNA por citometria de fluxo (FCM) e através da detecção de polimorfismos por análise de microssatélites (SSR). Nesta análise usaram-se ainda outros genótipos, nomeadamente: O. europaea ssp. europaea var. sylvestris, O. cerasiformes e O. europaea ssp. europaea var. europaea. Este estudo contribuiu para uma melhor caracterização desta espécie e permitiu a detecção de um nível de ploidia novo no género Olea (tetraploidia). O Capítulo II.3 descreve a optimização das condições de cultura in vitro (e.g. desinfecção, meio de cultura e enraizamento) para propagar e preservar a O. maderensis. Avalia-se ainda a “performance” dos rebentos in vitro (taxas de crescimento, avaliação da aparência das folhas e estudos fisiológicos), de modo a confirmar a optimização das condições de propagação. Neste capítulo define-se um meio novo (OMG) para propagação desta espécie endémica. O Capítulo II.4 descreve dois protocolos de micropropagação e aclimatização de ambas as espécies (O. maderensis e O. europaea ssp. europaea var. sylvestris) e a qualidade das plantas (“true-to-type”) é avaliada através da possível ocorrência de variabilidade genética através de FCM (ploidia) e SSRs. O Capítulo II.5 descreve um protocolo eficiente de aclimatização ao campo de O. maderensis e avalia a “performance” das plantas micropropagadas no campo através da análise de parâmetros fisiológicos durante o processo. O Capítulo II.6 apresenta os estudos em curso relativamente às plantas de O. maderensis em aclimatização no campo, bem como a introdução de plantas micropropagadas num outro local da Ilha com um maior grau de degradação dos solos. Estas estratégias estão a ser aplicadas juntamente com a DRFRAM, no âmbito de programas de florestação em curso. Finalmente é realçada a necessidade de estudos semelhantes com outras espécies nativas. Na Parte III, são apresentados os estudos sobre a percepção da comunidade local relativamente à valorização do coberto vegetal para a minimização dos processos de degradação dos solos/desertificação. A introdução faz o enquadramento teórico sobre o fenómeno da desertificação, particularmente na Ilha de Porto Santo e sobre a percepção social da desertificação. São ainda apresentados os objectivos específicos desta investigação. A metodologia adoptada recorreu à aplicação de inquéritos por questionário à população residente e aos visitantes da Ilha de Porto Santo e ainda a realização de inquéritos por entrevista a algumas entidades e especialistas. Estes estudos permitiram verificar que existe uma nítida consciência da situação de risco da ilha, das medidas tomadas e a tomar e da premência da resolução do problema. Face ao recurso de estratégias alternativas envolvendo biotecnologia, e apesar de existir algum desconhecimento, concluiu-se ainda que a população manifesta aceitação, desde que essas estratégias valorizem o coberto vegetal e, assim, ajudem a combater a degradação biofísica dos solos. Finalmente são apresentadas as conclusões e algumas recomendações. Na Parte IV apresentam-se as conclusões gerais e perspectivas futuras, onde o potencial ambiental destas oliveiras bravas micropropagadas é destacado, bem como é considerado o alargamento da aplicação destas estratégias a outras espécies indígenas em risco, nesta Ilha (e noutros locais). São ainda resumidas as principais visões da população e das entidades e dos especialistas que poderão contribuir para apoiar a elaboração de medidas de mitigação e prevenção no combate ao processo de degradação dos solos/desertificação em curso.