Effect of bacterial inoculation, plant genotype and developmental stage on root-associated and endophytic bacterial communities in potato (Solanum tuberosum)

Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is believed that specific bacterial functions are required for plant colonization, but also from the plant side specific features are needed, such as plant genotype (cultivar) and developmental stage. Via multivariate analysis we present a quantification of the roles of these components on the composition of root-associated and endophytic bacterial communities in potato plants, by weighing the effects of bacterial inoculation, plant genotype and developmental stage. Spontaneous rifampicin resistant mutants of two bacterial endophytes, Paenibacillus sp. strain E119 and Methylobacterium mesophilicum strain SR1.6/6, were introduced into potato plants of three different cultivars (Eersteling, Robijn and Karnico). Densities of both strains in, or attached to potato plants were measured by selective plating, while the effects of bacterial inoculation, plant genotype and developmental stage on the composition of bacterial, Alphaproteobacterial and Paenibacillus species were determined by PCR-denaturing gradient gel-electrophoresis (DGGE). Multivariate analyses revealed that the composition of bacterial communities was mainly driven by cultivar type and plant developmental stage, while Alphaproteobacterial and Paenibacillus communities were mainly influenced by bacterial inoculation. These results are important for better understanding the effects of bacterial inoculations to plants and their possible effects on the indigenous bacterial communities in relation with other plant factors such as genotype and growth stage

Cultivation of hitherto-uncultured bacteria belonging to the Verrucomicrobia subdivision 1 from the potato (Solanum tuberosum L.) rhizosphere

The role of dominant bacterial groups in the plant rhizosphere, e.g., those belonging to the phyla Acidobacteria and Verrucomicrobia, has, so far, not been elucidated, and this is mainly due to the lack of culturable representatives. This study aimed to isolate hitherto-uncultured bacteria from the potato rhizosphere by a combination of cultivation approaches. An agar medium low in carbon availability (oligotrophic agar medium) and either amended with potato root exudates or catalase or left unamended was used with the aim to improve the culturability of bacteria from the potato rhizosphere. The colony forming unit numbers based on colonies and microcolonies were compared with microscopically determined fluorescence-stained cell numbers. Taxonomical diversity of the colonies was compared with that of library clones made from rhizosphere DNA, on the basis of 16S rRNA gene comparisons. The oligotrophic media amended or not with catalase or rhizosphere extract recovered up to 33.6% of the total bacterial numbers, at least seven times more than the recovery observed on R2A. Four hitherto-uncultured Verrucomicrobia subdivision 1 representatives were recovered on agar, but representatives of this group were not found in the clone library. The use of oligotrophic medium and its modifications enabled the growth of colony numbers, exceeding those on classical agar media. Also, it led to the isolation of hitherto-uncultured bacteria from the potato rhizosphere. Further improvement in cultivation will certainly result in the recovery of other as-yet-unexplored bacteria from the rhizosphere, making these groups accessible for further investigation, e.g., with respect to their possible interactions with plants

Sobrevivência e obtenção de mutantes induzidos por agentes mutagênicos em Metarhizium anisopliae

Uma linhagem selvagem do fungo entomopatogênico Metarhizium anisopliae foi submetida à ação de três agentes mutagênicos: radiação gama, luz ultravioleta e ácido nitroso. Curvas de sobrevivência foram obtidas para cada mutagênicos utilizado e mutantes foram selecionados a partir de doses dos mutagênicos que proporcionassem de 1 a 5% de sobrevivência. Mutantes morfológicos para a coloração de conídios e mutantes auxotróficos foram isolados. Mutantes para coloração de conidios foram agrupados em duas classes, uma com conídios amarelos e outra com conídios vinho pálido. Os mutantes auxotróficos obtidos foram deficientes para aminoácidos e vitaminas e mais de 58% deles eram auxotróficos para prolina/argmina. Radiação gama foi o mutagênico mais eficiente com uma porcentagem de obtenção de mulantes auxotróficos de aproximadamente 0,2%, seguido pela luz ultravioleta (0.12%) e pelo ácido nitroso (0.06%).Os mulantes morfológicos e auxotróficos obtidos até o momento em Metarhizium anisopliae foram revistos.A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12%) and nitrous acid (0.06%).The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed

Gathering and managing complementary diagnostic tests

Personal health information is constituted in its greatest part by complementary diagnostic tests which are an important medical aid. This information is generated dispersedly because the patient seeks medical care in many different places over his lifetime. Access to a comprehensive set of a patient’s health information is a challenge. It revolves around the patient so any managing scheme must be patient-centric. We took a pragmatic approach to this problem and developed a software standalone platform for secure personal health information storage, namely complementary diagnostic tests, on a portable device for mobility. Simplicity and ease of use were main objectives. A special attention was given to the security aspects associated with storing this kind of information

Eliminação da produção de bacteriocinas em Erwinia e Pseudomonas fitopatogênicas

Four strains, two from each of the plant pathogenic bacteria Pseudomonas and Erwinia, all producing bacteriocins, were submitted to different treatments in order to evaluate the persistance of bacteriocin production. After ethidium bromide treatment elimination of the bacteriocin production was achieved and the percentage of loss varied with the host strain and drug concentration. Elimination was not detected after treatment with high temperatures, above the normal ones. Also preservation of the strains for three years, in laboratory, did not cause elimination of the character. The curing of bacteriocin production after ethidium bromide treatment suggests that the involved genes are located in plasmids.Duas linhagens de bactérias fitopatogênicas do gênero Pseudomonas e duas do gênero Erwinia produtoras de bacteriocinas, foram submetidas a diferentes tratamentos visando estimar a estabilidade desse caráter. Houve eliminação da produção de bacteriocinas após tratamento com duas concentrações de brometo de etídio e a porcentagem de eliminação variou com o hospedeiro e com a concentração da droga. Não houve eliminação em temperaturas elevadas e também a preservação da linhagem por três anos em laboratório não causou perda do caráter. A eliminação da produção de bacteriocinas com brometo de etídio sugere que os genes envolvidos tenham localização plasmidiana

Detecção de bacteriocinas produzidas por bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas

Detection of bacteriocin production was studied under distinct conditions using strains of plant pathogenic bacteria from the genera Erwinia, Pseudomonas and Xanthomonas. 58.06%, 79.31% and 40.00% of producing strains were found respectivelly in the three groups of bacteria using the 523 medium which was the best for the detection of bacteriocin production. Increasing agar concentrations added to the medium up to 1,5% improved the detection. The amount of medium added to the Petri dishes did not affect bacteriocin production. The longest incubation time (72h.) improved the detection of haloe production. Ultra-violet irradiation in low dosages seems to improve the visualization of haloe prodution but this is dependent on the tested strains.A detecção da produção de bacteriocinas foi estudada em diferentes condições, utilizando-se linhagens de bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas. Obtiveram-se, respectivamente, 58,06%, 71,31% e 40,00% de linhagens produtoras no meio 523, que foi o mais indicado para detecção dessa produção. Uma maior concentração de ágar adicionada ao meio (1,5%) produziu melhores resultados mas, a quantidade de meio nas placas não influenciou a detecção de bacteriocinas. O maior tempo de incubação utilizado (72 h.) facilitou detecção de halos de produção de bacteriocinas. Irradiação com luz ultra-violeta em baixas doses parece facilitar a liberação de bacteriocinas, mas isso varia com a linhagem empregada

Solution Of The Urban Traffic Problem With Fixed Demand Using Inexact Restoration

Congested traffic has become a part of the day-to-day for the residents of big metropolitan centers. From an economic viewpoint, this problem has been causing huge financial damage and strategic measures must be taken to tackle it. An alternative means of solving the problem is the inclusion of toll charges on routes with a view to decongesting the road network. The mathematical formulation of this alternative involves the solving of an optimization problem with equilibrium constraints (MPEC). This work proposes an algorithm for the solution of this problem based on the strategy of inexact restoration.837-4019071918Andreani, R., Castro, S.L.C., Chela, J.L., Friedlander, A., Santos, S.A., Aninexact-restoration method for nonlinear bilevel programming problems (2009) Comput. Optim. Appl., 43, pp. 307-328Andreani, R., Martinez, J.M., Svaiter, B.F., On the Regularization of mixed complementarity problems (2000) Numerical Functional Analysis and Optimization, 21, pp. 589-600Andreani, R., Martinez, J.M., On the reformulation od Nonlinear Complementarity Problems using the Fischer-Burmeister function (1999) Applied Mathematics Letters, 12, pp. 7-12Andreani, R., Friedlander, A., Bound Constrained Smooth Optimization for Solving Variational Inequalities and Related Problems (2002) Annals of Operations Research, 116, pp. 179-198Arnott, R., Small, K., (1994) The economics of traffic congestion, , Boston College Working Papers in Economics 256, Boston College, Department of EconomicsBazarra, M.S., Sherali, H.D., Shetty, C.M., (1993) Nonlinear Programming: Theory and Algoritms, , Second Edition, John Wiley & Sons, New YorkBonnans, J.F., Shapiro, A., (2000) Perturbation Analysis of Optimization Problems, , Springer Series in Operations Research, SpringerBrotcorne, L., Labbé, M., Marcotte, P., Savard, G., A Bilevel Model for Toll Optimization on a Multicommodity Transportation Network (2001) Transportation Science, 35 (4), pp. 345-358Calamai, P.H., Vicente, L.N., Generating quadratic bilevel programming test problems (1994) ACM Transactions on Mathematical Software, 20, pp. 103-119Chela, J.L., (2006) Resolução do problem a de programao matemática com restrições de equilíbrio usando restauração inexata, , PhD thesis, University of CampinasFerrari, P., Road network toll pricing and social welfare (2002) Trans. Res. B, 36, pp. 471-483Harker, P.T., Pang, J.S., Existence of optimal solutions to mathematical programs with equilibrium constraints (1988) Operations Research Letters, 7 (2), pp. 61-64Hearn, D.W., (1980) Bounding Flows in Traffic Assignment Models, , Research report N.80-4, Dept. of Industrial and Systems Enginnering, University of Florida, Gainesville, FL 32611Hearn, D.W., Ramana, M.V., Solving congestion toll princing models (1998) Equilibrium and Advanced Transportation Modelling, pp. 109-124. , P. Marcotte, S. Nguyen (eds), Kluwer Academic Publisher, Boston, The NetherlandsHearn, D.W., Yildirim, M.B., A toll pricing framework for traffic assignment problems with elastic demands (2001) Current Trends in Transportation and Network Analysis: Miscellanea in Honor of Michael Florian, , M. Gendreau, P. Marcotte(eds), Kluwer Academic Publisher, Dordrecht, The NetherlandsHearn, D.W., Lawphongpanich, S., An MPEC approach to second-best toll pricing (2004) Mathematical Programming Series B, 101, pp. 33-55Hearn, D.W., Bergendorff, P., Ramana, M.V., Congestion Toll Pricing of Traffic Networks, Network Optimization (1997) Lecture Notes in Economics and Mathematical Systems, 450, pp. 51-71. , P. M. Pardalos, D.W. Hearn and W.W. Hager (Eds.), Springer-VerlagJohansson-Stenman, O., Sterner, T., What is the scope for environmental road pricing? (1998) Road pricing Traffic Congestion and Environment, , K.J. Button, E.T. Verhoef (eds.), Edward Elgar Publishing Limited, London, EnglandLabbé, M., Marcotte, P., Savard, G., A bilevel model of taxation and its application to optimal highway pricing (1998) Manage. Sci, 44 (12), pp. 1608-1622Migdalas, A., Bilevel Programming in traffic planning: models, methods and challenge (1994) Journal of Global Optimization, 4, pp. 340-357Patriksson, M., Rockafellar, R.T., A Mathematical model and descent algorithm for bilevel traffic management (2002) Trans. Sci, 36, pp. 271-291Solodov, M.V., Svaiter, B.F., A New Projection Method for Variational Inequality Problems (1999) SIAM Journal Control Optimization, 37, pp. 765-77

Evaluation of mitochondrial activity in spermatozoids after collecting and posthawing in Boer and Alpine goats in autumn and spring

Caprine spermatozoa undergo glycolisis and mitocondrial respiration to keep the necessary energy balance to their transportation and other cellular functions. An objective test to evaluate quantitatively and qualitatively mitochondrial activity in caprine spermatozoa was applied in the analysis of semen samples of 9 bucks from Boer (n=5) and Alpine (n=4) breeds. Samples were collected and frozen in TRIS medium in two different year seasons. Semen collection was performed using artificial vagina to obtain 135 ejaculates, which were used to post-collection and post-frozen extended in sildes. To determine mitochondrial activity, a citochemical procedure developed and validated for HRUDKA (1987) was used. The technique is based on the enzymatic 3,3-diaminobenzidine (DAB) oxidation, where the reagent is polymerized and attached to the mitochondrial membrane throughout the spermatic intermediary piece. A medium level of citochemical activity (IAC) was determined as being 74,37%, 74,37% during Autumn and 77% e 77,75% during Spring for Boer and Alpine breeds, respectively. For post-collection IAC levels were 85,62% and 85,93 and for post-frozen 66% and 67,25% for Boer and Alpine breeds, respectively. ANOVA test was used to evaluate breed, post-collection, post-frozen, IAC rates and year season parameters. Differences were not noticed for breed, IAC rates and year season. Nonetheless, there was a significant effect among samples for post-collection and post-frozen analysis (POs espermatozóides caprinos realizam a respiração mitocondrial, mantendo um balanço energético necessário para o transporte e as demais funções celulares. Um teste objetivo de avaliação quantitativa e qualitativa da atividade mitocondrial em espermatozóides caprinos foi aplicado no sêmen de nove reprodutores das raças Boer (n=5) e Alpina (n=4) colhidos e congelados em diluidor TRIS em duas estações. A colheita do sêmen foi realizada com auxílio da vagina artificial, totalizando 135 ejaculados e foram confeccionados esfregaços com sêmen pós-colheita e pós-descongelação. Para a determinação da atividade mitocondrial foi utilizado o procedimento citoquímico desenvolvido e validado por HRUDKA (1987). Esta técnica é baseada na oxidação da 3,3-diaminobenzidine (DAB) pela enzima em reação em cadeia, onde o reagente é polimerizado e depositado na bainha mitocondrial ao longo da peça intermediária dos espermatozóides. Foi determinado um índice médio de atividade citoquímica (IAC) de 74,37%, 74,37% no outono, 77% e 77,75% na primavera. E 85,62% e 85,93 no pós-colheita, 66% e 67,25% pós-descongelação para as raças Boer e Alpina, respectivamente. As variáveis raças, pós-colheita e pós-descongelação, classes (IAC), e estação foram estudadas por meio de ANOVA. Não foram observadas diferenças estatísticas para raças, classes, bem como para as estações. Entretanto, efeito significativo entre as amostras pós-colheita e pós-descongelação (