Time-to-positivity, type of culture media and oxidase test performed on positive blood culture vials to predict Pseudomonas aeruginosa in patients with Gram-negative bacilli bacteraemia / Tiempo de positividad, tipo de medio de cultivo y prueba de oxidasa realizada en viales de hemocultivo positivos para predecir Pseudomonas aeruginosa en pacientes con bacteriemia por bacilos gramnegativos

Introduction. The aim of this study was to determine the usefulness of oxidase test and time-to-positivity (TTP) in aerobic and anaerobic blood culture vials to detect the presence of Pseudomonas aeruginosa in patients with Gram-negative bacilli (GNB) bacteraemia. Material and methods. TTP was recorded for each aerobic and anaerobic blood culture vial of monomicrobial bacteraemia due to GNB. Oxidase test was performed in a pellet of the centrifuged content of the positive blood culture. An algorithm was developed in order to perform the oxidase test efficiently taking into account TTP and type of vial. Results. A total of 341 episodes of GNB bacteraemia were analysed. Sensitivity, specificity, positive predictive value and negative predictive value of the oxidase test performed on positive vials with GNB to predict P. aeruginosa were 95%, 99%, 91%, and 99%, respectively. When growth was first or exclusively detected in anaerobic vials, P. aeruginosa was never identified hence the performance of the oxidase test could be avoided. When growth was only or first detected in aerobic vials, a TTP≥8h predicted P. aeruginosa in 37% or cases (63 of 169), therefore oxidase test is highly recommended. Conclusions. Oxidase test performed onto positive blood culture vials previously selected by TTP and type of vials is an easy and inexpensive way to predict P. aeruginosa. In most cases, this can lead to optimization of treatment in less than 24 hours (AU)

Introducción. El objetivo del estudio fue determinar la utilidad de la prueba de oxidasa y del tiempo de positividad del hemocultivo (TPH) para detectar la presencia de Pseudomonas aeruginosa en pacientes con bacteriemia por bacilos gramnegativos (BGN). Material y métodos. Se registró el TPH de cada vial aerobio y anaerobio en todos los episodios de bacteriemia monomicrobiana por BGN. La prueba de oxidasa se realizó sobre el contenido centrifugado del hemocultivo positivo. Se diseñó un algoritmo para optimizar la realización de la prueba de oxidasa según el TPH y el tipo de vial. Resultados. Se analizaron 341 episodios de bacteriemia por BGN. La sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo de la prueba de oxidasa para predecir P. aeruginosa fueron del 95%, 99%, 91% y 99%, respectivamente. Cuando el crecimiento se detectó primero o exclusivamente en viales anaerobios, nunca se identificó P. aeruginosa pudiendo evitar la realización de la prueba de oxidasa. Cuando el crecimiento se detectó antes o exclusivamente en viales aerobios un TPH ≥8h predijo la presencia de P. aeruginosa en el 37% de los casos (63 de 169), por lo que es recomendable la realización de la prueba de oxidasa. Conclusiones. La prueba de oxidasa realizada a viales de hemocultivos positivos previamente seleccionados por el TPH y el tipo de medio es una forma fácil y económica de predecir P. aeruginosa. En la mayoría de los casos, esto puede contribuir a la optimización del tratamiento antibiótico en menos de 24h (AU)

Spatiotemporal proliferation of human stromal cells adjusts to nutrient availability and leads to stanniocalcin-1 expression in vitro and in vivo.

Cells and tissues are intrinsically adapted to molecular gradients and use them to maintain or change their activity. The effect of such gradients is particularly important for cell populations that have an intrinsic capacity to differentiate into multiple cell lineages, such as bone marrow derived mesenchymal stromal cells (MSCs). Our results showed that nutrient gradients prompt the spatiotemporal organization of MSCs in 3D culture. Cells adapted to their 3D environment without significant cell death or cell differentiation. Kinetics data and whole-genome gene expression analysis suggest that a low proliferation activity phenotype predominates in stromal cells cultured in 3D, likely due to increasing nutrient limitation. These differences implied that despite similar surface areas available for cell attachment, higher cell concentrations in 3D reduced MSCs proliferation, while activating hypoxia related-pathways. To further understand the in vivo effects of both proliferation and cell concentrations, we increased cell concentrations in small (1.8 µl) implantable wells. We found that MSCs accumulation and conditioning by nutrient competition in small volumes leads to an ideal threshold of cell-concentration for the induction of blood vessel formation, possibly signaled by the hypoxia-related stanniocalcin-1 gene.

Coaxial nozzle-assisted 3D bioprinting with built-in microchannels for nutrients delivery.

This study offers a novel 3D bioprinting method based on hollow calcium alginate filaments by using a coaxial nozzle, in which high strength cell-laden hydrogel 3D structures with built-in microchannels can be fabricated by controlling the crosslinking time to realize fusion of adjacent hollow filaments. A 3D bioprinting system with a Z-shape platform was used to realize layer-by-layer fabrication of cell-laden hydrogel structures. Curving, straight, stretched or fractured filaments can be formed by changes to the filament extrusion speed or the platform movement speed. To print a 3D structure, we first adjusted the concentration and flow rate of the sodium alginate and calcium chloride solution in the crosslinking process to get partially crosslinked filaments. Next, a motorized XY stages with the coaxial nozzle attached was used to control adjacent hollow filament deposition in the precise location for fusion. Then the Z stage attached with a Z-shape platform moved down sequentially to print layers of structure. And the printing process always kept the top two layers fusing and the below layers solidifying. Finally, the Z stage moved down to keep the printed structure immersed in the CaCl2 solution for complete crosslinking. The mechanical properties of the resulting fused structures were investigated. High-strength structures can be formed using higher concentrations of sodium alginate solution with smaller distance between adjacent hollow filaments. In addition, cell viability of this method was investigated, and the findings show that the viability of L929 mouse fibroblasts in the hollow constructs was higher than that in alginate structures without built-in microchannels. Compared with other bioprinting methods, this study is an important technique to allow easy fabrication of lager-scale organs with built-in microchannels.

Invasion of solid culture media: a widespread phenotypic feature of clinical bacterial isolates

Objetivos. El crecimiento en profundidad en medios de cultivo sólidos es un fenómeno habitual en hongos filamentosos y levaduras. Sin embargo, son muy escasas las especies bacterianas en las que se ha documentado este fenómeno. El objetivo de este trabajo fue comprobar la capacidad de invasión del agar de un amplio abanico de especies bacterianas grampositivas y gramnegativas de interés clínico. Material y métodos. Se cultivaron tres cepas de cada una de once especies bacterianas sobre agar Columbia hasta un máximo de 15 días. Colonias aisladas fueron procesadas e incluidas en resina epoxi por métodos histológicos y secciones transversales semifinas teñidas con azul de toluidina fueron visualizadas por microscopía óptica. Resultados. Se observó crecimiento en el interior del agar en al menos una de las cepas de nueve de las especies estudiadas. En bacilos gramnegativos, las invasiones eran escasas en número, pequeñas y con morfología redondeada o triangular. En cocos grampositivos las invasiones eran de gran tamaño, numerosas y de morfología variable (lentiforme, globular, irregular, en forma de punta de flecha, etc.) según la especie. Conclusiones. En nuestra opinión, el crecimiento en el interior del agar puede significar una estrategia de supervivencia común a muchas especies bacterianas y hasta ahora prácticamente no descrita. Esta estrategia podría ser el reflejo de un tropismo a favor de gradiente de nutrientes, o bien un fenómeno de diseminación y colonización de nuevos nichos ecológicos, con posibles implicaciones en la patogenia(AU)

Objectives. The in-depth growth in solid culture media is a common feature in filamentous fungi and yeasts. However, there are very few bacterial species in which this phenomenon has been documented. The aim of this work was to assess the agar invasiveness of a wide range of Gram-positive and Gram-negative bacterial species of clinical interest. Material and methods. Three different clinical isolates for each of eleven bacterial species were plated onto Columbia blood agar and let grow up to 15 days. Isolated colonies were processed by histological methods, embedded in epoxy resin, and then, semithin sections were stained with toluidine blue and visualized by light microscopy. Results. Growth within the agar was observed in at least one strain in 9 of the 11 studied species. Invasions of Gramnegative rods were small, not plentiful, and round or triangleshaped. In Gram-positive cocci, invasions were of big size, abundant and of variable shape (lentiform, globular, irregular, arrowhead) depending on the species. Conclusions: We propose that the growth within the agar can indicate a survival strategy common to many bacterial species, and so far, not previously reported. This strategy could be either a nutrient gradient tropism or the spread and colonization of new ecological niches, with potential implications in pathogeny(AU)

Susceptibilidad antibiótica in vitro a fluoroquinolonas / In vitro antibiotic susceptibility to fluoroquinolones

Objetivo: Determinar la susceptibilidad antibiótica de la bacterias obtenidas en cultivos de infecciones oculares en la Fundación Oftalmológica de Santander - Clínica Carlos Ardila Lulle (FOSCAL). Materiales y métodos: Estudio descriptivo retrospectivo de una serie de registros de cultivos de muestras de superficie ocular y líquidos intraoculares del laboratorio OCULAB-FOSCAL en Floridablanca (Colombia) realizados entre enero y diciembre de 2007. Se realizó antibiograma por el método de Kirby-Bauer con sensi-discos impregnados de concentraciones determinadas de antibiótico. Resultados: Se recogieron un total de 352 muestras de los cuales 160 fueron de conjuntiva, 150 fueron de córnea y 42 de líquidos intraoculares. Se recuperó más de un microorganismo en el 45,65% del total de las muestras. El 78,7 y el 18,4% de las bacterias identificadas correspondieron a Gram positivos y a Gram negativos, respectivamente. El 6,3, 8,9, 33,2 y 35,6% de las bacterias Gram positivas fueron resistentes a gatifloxacino, moxifloxacino, ciprofloxacino y levofloxacino, respectivamente. El 7,4, 16,7, 16,7 y 25,9% de las bacterias Gram negativas fueron resistentes a gatifloxacino, moxifloxacino, ciprofloxacino y levofloxacino, respectivamente. La resistencia bacteriana global (tanto Gram positivos como Gram negativos) a moxifloxacino fue del 10,15% y a gatifloxacino del 6,46%, siendo esta diferencia estadísticamente significativa (p<0,05)(AU)

Conclusiones: En nuestro estudio, se evidenció el desarrollo de resistencia bacteriana en muestras oculares incluso con las fluoroquinolonas de cuarta generación. Sin embargo se encontraron menores niveles de resistencia para las fluoroquinolonas de cuarta generación que para las de tercera y segunda generación, especialmente entre Gram positivos. Gatifloxacino mostró menores niveles de resistencia que la moxifloxacino. La interpretación de esta superioridad debe, sin embargo, hacerse con cuidado en el campo clínico, ya que se deben tener en cuenta otros factores como la penetración tisular y la actividad in vivo(AU)

Objective: To determine the antibiotic susceptibility of bacteria recovered from cultures of ocular infections in the Fundación Oftalmológica de Santander - Clínica Carlos Ardila Lulle (FOSCAL). Materials and methods: Retrospective descriptive study of a series of registries of cultures of samples from ocular surfaces and intraocular fluids from the OCULAB-FOSCAL laboratory in Floridablanca (Colombia) made between January and December of 2007. Antibiotic sensitivity screening by the method of Kirby-Bauer with impregnated Sensi-Discs™ of determined antibiotic concentrations was performed. Results: A total of 352 samples were studied: 160 from conjunctiva, 150 from cornea and 42 from intraocular fluids. Of the total of the samples more than one microorganism was recovered 45.65% of the samples. Gram positive and Gram negative bacteria were identified in 78.7 and 18.4%, respectively. Resistance to gatifloxacin, moxifloxacin, ciprofloxacin and levofloxacin was observed in 6.3, 8.9, 33.2 and 35.6%, respectively, of Gram positive bacteria. Resistance to gatifloxacin, moxifloxacin, ciprofloxacin and levofloxacin was also observed in 7.4, 16.7, 16.7%and 25.9%, respectively, of Gram negative bacteria. The overall bacterial resistance (Gram positive and Gram negative) to moxifloxacin was 10.15%, and to gatifloxacin it was 6.46%, being which showed a statistically significant difference (P<.05). Conclusions: In our study the development of bacterial resistance to fourth generation fluoroquinolones was demonstrated in ocular samples. However, lower levels of resistance to fourth generation fluoroquinolones compared with that of third and second generation were found, particularly to Gram positive. Gatifloxacin showed lower resistance levels than moxifloxacin. Nevertheless, interpretation of this superiority must be made with caution in the clinical field, since other factors, like tissue penetration and in vivo activity, must be taken into account(AU)

Dissolution kinetics of iron-, manganese-, and copper-containing synthetic hydroxyapatites.

Micronutrient-substituted synthetic hydroxyapatite (SHA) is being evaluated by the National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program for crop production on long-duration human missions to the International Space Station or for future Lunar or Martian outposts. The stirred-flow technique was utilized to characterize Ca, P, Fe, Mn, and Cu release characteristics from Fe-, Mn-, and Cu-containing SHA in deionized (DI) water, citric acid, and diethylene-triamine-pentaacetic acid (DTPA). Initially, Ca and P release rates decreased rapidly with time and were controlled by a non-SHA calcium phosphate phase(s) with low Ca/P solution molar ratios (0.91-1.51) relative to solid SHA ratios (1.56-1.64). At later times, Ca/P solution molar ratios (1.47-1.79) were near solid SHA ratios and release rates decreased slowly indicating that SHA controlled Ca and P release. Substituted SHA materials had faster dissolution rates relative to unsubstituted SHA. The initial metal release rate order was Mn >> Cu > Fe which followed metal-oxide/phosphate solubility suggesting that poorly crystalline metal-oxides/phosphates were dominating metal release. Similar metal release rates for all substituted SHA (approximately 0.01 cmol kg-1 min-1) at the end of the DTPA experiment indicated that SHA dissolution was supplying the metals into solution and that poorly crystalline metal-oxide/phosphates were not controlling metal release. Results indicate that non-SHA Ca-phosphate phases and poorly crystalline metal-oxide/phosphates will contribute Ca, P, and metals. After these phases have dissolved, substituted SHA will be the source of Ca, P, and metals for plants.

Multiple forms of microbial enzymes.

Multiple forms of one enzyme occur in a wide variety of microorganisms. Their synthesis is often dependent on culture characteristics such as medium composition, physico-chemical parameters, culture age and the presence of inducing or inhibiting agents. Multiform enzymes increase the capability of the producing organism to adapt to and cope with a wide variety of environmental changes, such that the physiological advantages outweigh the apparent wasteful hyperproduction of multiple forms of one enzyme.

Sonobioreactors: using ultrasound for enhanced microbial productivity.

Enhanced metabolic productivity of microbial, plant and animal cells in bioreactors can greatly improve the economics of biotechnology processes. Ultrasound is one method of intensifying the performance of live biocatalysts. Ultrasonication is generally associated with damage to cells but evidence is emerging for beneficial effects of controlled sonication on conversions catalyzed by live cells. This review focuses on the productivity enhancing effects of ultrasound on live biological systems and the design considerations for sonobioreactors required for ultrasound-enhanced biocatalysis.

Minimal reaction sets for Escherichia coli metabolism under different growth requirements and uptake environments.

A computational procedure for identifying the minimal set of metabolic reactions capable of supporting various growth rates on different substrates is introduced and applied to a flux balance model of the Escherichia coli metabolic network. This task is posed mathematically as a generalized network optimization problem. The minimal reaction sets capable of supporting specified growth rates are determined for two different uptake conditions: (i) limiting the uptake of organic material to a single organic component (e.g., glucose or acetate) and (ii) allowing the importation of any metabolite with available cellular transport reactions. We find that minimal reaction network sets are highly dependent on the uptake environment and the growth requirements imposed on the network. Specifically, we predict that the E. coli network, as described by the flux balance model, requires 224 metabolic reactions to support growth on a glucose-only medium and 229 for an acetate-only medium, while only 122 reactions enable growth on a specially engineered growth medium.

New miniaturized hollow-fiber bioreactor for in vivo like cell culture, cell expansion, and production of cell-derived products.

We have developed a miniaturized hollow-fiber bioreactor system for mammalian cell culture with a volume of 1 mL. Cell and medium compartments of the bioreactor are separated by a semipermeable membrane, and oxygenation of the cell compartment is accomplished using an oxygenation membrane. As a result of the geometry of the transparent housing, cells can be observed by microscopy during culture. The leukemic cell lines CCRF-CEM, HL-60, and REH were cultivated up to densities of 3.5 x 10(7)/mL without medium change or manipulation of the cells. As shown using CCRF-CEM cells, growth in the bioreactor was strongly influenced and could be controlled by the medium flow rate. As a consequence, consumption of glucose and generation of lactate varied with flow rate. Depending on the molecular size cutoff of the membranes used, added growth factors such as GM-CSF, as well as factors secreted from the cells, are retained in the cell compartment for up to 1 week. This new miniaturized hollow-fiber bioreactor offers advantages in tissue engineering by continuous nutrient supply for cells in high density, retention of added or autocrine produced factors, and undisturbed long-term culture in a closed system.

Physical-chemical treatment of wastes: a way to close turnover of elements in LSS.

"Man-plants-physical-chemical unit" system designed for space stations or terrestrial ecohabitats to close steady-state mineral, water and gas exchange is proposed. The physical-chemical unit is to mineralize all inedible plant wastes and physiological human wastes (feces, urine, gray water) by electromagnetically activated hydrogen peroxide in an oxidation reactor. The final product is a mineralized solution containing all elements balanced for plants' requirements. The solution has been successfully used in experiments to grow wheat, beans and radish. The solution was reusable: the evaporated moisture was replenished by the phytotron condensate. Sodium salination of plants was precluded by evaporating reactor-mineralized urine to sodium saturation concentration to crystallize out NaCl which can be used as food for the crew. The remaining mineralized product was brought back for nutrition of plants. The gas composition of the reactor comprises O2, N2, CO2, NH3, H2. At the reactor's output hydrogen and oxygen were catalyzed into water, NH3 was converted in a water trap into NH4 and used for nutrition of plants. A special accessory at the reactor's output may produce hydrogen peroxide from intrasystem water and gas which makes possible to close gas loops between LSS components.

Wheat response to differences in water and nutritional status between zeoponic and hydroponic growth systems.

Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L. cv. USU-Apogee). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15 to 20 L m-2 d-1 up to Day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences in water status were noted between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT than in hydroponic culture. Sterile green tillers made up 12 and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4-N nutrition of plants grown in ZPT compared with NO3-N in hydroponic nutrient solution. It is probable that NH4-N-induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS.

Meio CE e glutaraldeído na preservaçäo de plaquetas para o controle de qualidade em hematimetria / CE medium and gluutaraldehyde in platelets preservation for control quality in hematology

Controles comerciais para todas as medidas hematológicas só se tornaram disponíveis no início da década de 60, sendo que ainda há falta de padronizaçäo apropriada para diversas medidas envolvendo componentes celulares. As amostras comerciais de células consistem de células de sangue humano ou de outros animais, alteradas para retardar a deterioraçäo. De um modo geral, os fabricantes utilizam para essas células os termos: fixadas, tamponadas, estabilizadas ou preservadas, para indicar o seu processo de preparo, sem contudo descrevê-lo. Em trabalhos anteriores, desenvolveu-se amostras adequadas ao controle de qualidade em hematimetria, estáveis para os valores do eritrograma durante 100 dias, pela preservaçäo de eritrócitos em meio CE, composto por glicose, NaCl, citrato de sódio, fosfato monohidrógeno de sódio, KCl, EDTANa2, albumina bovina, clormicetina, neomicina e cortisona e pela fixaçäo parcial com glutaraldeído [ Leonart, Rev. Bras. Anál. Clín. 21: 111, 1989 ]. O uso de soluçöes aditivas para o armazenamento de concentrados de plaquetas tem aumentado durante os últimos anos e se tornado frequente na prática clínica. Em testes preliminares, realizados com o meio CE para a preservaçäo de plaquetas humanas, observamos estabilidade para a sua contagem durante até 35 dias [ Emendörfer et al, Rev. Bras. Anál. Clín. 31:18, 1999]. A partir de 20 amostras de sangue venoso em EDTAK2 e da obtençäo do plasma rico em plaquetas, testou-se a fixaçäo parcial em glutaraldeído, com posterior ressuspensäo das plaquetas em meio CE, obtendo-se valores estáveis para contagem em Coulter Counster T890 durante até 50 dias. Foram estudadas modificaçöes na composiçäo do meio CE nas concentraçöes de 1 a 6 g/gL de albumina bovina, obtendo-se maior estabilidade para as amostras de plaquetas preservadoras na concentraçäo de 6 g/dL, como empregada no meio CE original. No entanto, em amostras fixadas com glutaraldeído näo se observou diferenças na contagem das plaquetas durante 50 dias, independentemente da concentraçäo de albumina bovina. Os resultados obtidos sugerem que a fixaçäo parcial com glutaraldeído pode ser adequada para a estabilizaçäo de plaquetas em amostras de controle de qualidade.

[The effect of the nutritional sources on the synthesis of exopolysaccharides and amino acids by Bacillus subtilis strains]. / Vliianie istochnikov pitaniia na sintez ékzopolisakharidov i aminokislot shtammami Bacillus subtilis.

Dynamics of cell biomass accumulation and secretion to the medium extracellular polysaccharides and amino acids has been studied in Bacillus subtilis cultures No No 39 and 51 used to produce healing biopreparations--probiotics. The investigation data indicate to certain relation between these processes. EPS secretion in the studied cultures proceeded parallel with their growth and started in the logarithmic phase. Maximum EPS yield was observed by the beginning of the stationary phase after 10-12 h of growth. A successible change in the amino acid content in the medium was observed in the growth process of the studied bacteria: the bacteria first consumed amino acids of the initial medium and then excreted amino acids synthesized into the medium. Under the active production of EPS the content of extracellular amino acids in the medium was inconsiderable. The content of EPS was lower during accumulations of high concentrations of extracellular amino acids. Role of the medium components in regulation of the studied processes has been shown. The ratio C:N in the medium was of essential significance. The C:N ratio 2.0-3.0:1.0 was optimal both for the growth and secretion of EPS by the studied cultures while that of 1.0-1.5:1.0 was optimal for production of the extracellular amino acids. The increase of C:N ratio resulted in the decrease of metabolites secretion by the cultures.

Iodate and iodide effects on iodine uptake and partitioning in rice (Oryza sativa L.) grown in solution culture.

In the Xinjiang province of western China, conventional methods of iodine (I) supplementation (i.e, goiter pills and iodinated salt) used to mitigate I deficiencies were ineffectual. However, the recent addition of KIO3 to irrigation waters has proven effective. This study was conducted to determine the effects of I form and concentration on rice (Oryza sativa L.) growth, I partitioning within the plant, and ultimately to assist in establishing guidelines for incorporating I into the human food chain. We compared IO3- vs. I- in order to determine how these chemical species differ in their biological effects. Rice was grown in 48 L aerated tubs containing nutrient solution and IO3- or I- at 0, 1, 10, or 100 micromoles concentrations (approximately 0, 0.1, 1, and 10 mg kg-1 I). The IO3- at 1 and 10 micromoles had no effect on biomass yields, and the 100 micromole treatment had a small negative effect. The I- at 10 and 100 micromoles was detrimental to biomass yields. The IO3- treatments had more I partitioning to the roots (56%) on average than did the I- treatments (36%), suggesting differences in uptake or translocation between I forms. The data support the theory that IO3- is electrochemically or biologically reduced to I- prior to plant uptake. None of the treatments provided sufficient I in the seed to meet human dietary requirements. The I concentration found in straw at 100 micromoles IO3- was several times greater than seed, and could provide an indirect source of dietary I via livestock feeding on the straw.

Role of endotoxin in tumor necrosis factor alpha expression from alveolar macrophages treated with urban air particles.

The effects of urban air and diesel particles on inflammatory cytokine gene expression, tumor necrosis factor alpha (TNF-alpha) in particular, were studied in rat alveolar macrophages. TNF-alpha, interleukin (IL)-1, IL-6, cytokine-induced neutrophil chemoattractant (CINC), and macrophage inflammatory protein (MIP)-2 gene expression and TNF-alpha secretion were increased in cells treated with 50 to 200 micrograms/mL of urban air particles in a concentration-related manner. There was no cytokine induction by diesel particles at any of the concentrations tested. Cytokine expression was not related to reactive oxygen species since antioxidants, such as catalase, TMTU, or DMSO, had no effect on TNF-alpha secretion. However, cytokine induction by urban air particles was completely prevented by polymyxin B, an antibiotic capable of neutralizing bacterial lipopolysaccharide (LPS) activities. Furthermore, LPS was detected on the urban air particles, but not on diesel particle. These results suggest that activation of cytokine gene expression and secretion in rat alveolar macrophages by urban air particles is due to the presence of endotoxin on the particles.

Flocculation and fermentation capacity of strains of saccharomyces stored at mycotheca-urm.I

Cepas de Saccharomyces mantenidas en la micoteca-URM, fueron estudiadas en relación a su capacidad de fermentar y flocular en una solución acuosa de melaza a 18º Brix. De estas, 11 pertenecian a S. cerevisiae y 1 a S.kluyveri. El mayor contenido de etanol (6,02 porciento v/v) fue obtenido con la cepa 1460 y el menor (1,39 porciento v/v) con la 2664. Los menores porcentaje de células que permanecen en suspensión (R porciento), 65,82 porciento, 65,31 porciento, 41,66 porciento y 55,55 porciento, fueron obtenidos respectivamente con las cepas 2659, 2624, 2716 y 1337, indicando una mayor intensidad de floculación. Las cepas 2659 y 2716 produjeron una mayor concentración de etanol. Los resultados indican que una cepa de Saccharomyces puede o no expresar conjuntamente una buena capacidad de fermentación y floculación

Effect of ph and temperature on the fermentation and flocculation capacity of strains of saccharomyces stored at mycotheca-urm. II

Se determinó el efecto conjunto del ph del medio de cultivo (solución acuosa al 10 porciento de melaza) y de la temperatura de incubación, en la expresión de la capacidad de fermentación y floculación de 12 cepas de Saccharomyces conservadas en la Micoteca-URM. De estas, 11 pertenecen a S. cerevisiae y 1 a S. Kluyvery. Se utilizaron dos valores de ph (4,5 y 5) y 3 temperaturas: 28ºC no es igual a 1ºC (temperatura ambiente), 25ºC y 37ºC. Todas las cepas fermentaron en los dos ph y a las tres temperaturas, variando en relación al período de fermentación. Sin embargo, los períodos de floculación y fermentación mostraron variación frente a ambos parámetros

Release of extracellular polysaccaride by spondylosium panduriforme (desmidiaceae)

A desmidiacea filamentosa Spondylosium panduriforme tem uma bainha mucilaginosa relativamente grande e consistente. Usando C14 como marcador foi estudada a liberaçäo de polissacarídeo extracellular solúvel e a marcaçäo dos polissacarídeos da bainha durante 28 horas seguidas. O polissacarídeo solúvel pode ser detectado no meio de cultura uma hora após a adiçäo do marcador enquanto o polissacarídeo da bainha pode ser detectado meia hora depois. Os resultados mostram que a viscosidade no meio de cultura desta espécie näo devida dissoluçäo das bainhas de células velhas, como se pensava. Há evidências que o polissacarídeo solúvel pode ser produzido por um ativo processo fisiológico

[The effect of physicochemical factors on the growth of Pseudomonas putida BS-2 on a medium with diethylene glycol]. / Vliianie fiziko-khimicheskikh faktorov na rost Pseudomonas putida BS-2 na srede s diétilenglikolem.

The physicochemical factors of medium have been studied for their effect on the physiological indices of growth of Pseudomonas putida BS-2 culture utilizing diethylenglycol as the only source of carbon. Action of the supraoptimal temperature on the growth process of P. putida BS-2 is accompanied by a decrease (more than twice) in economic coefficient of substrate and specific growth rate as compared with their maximal values. Dependences of specific growth rate of P. putida BS-2 in the medium with diethylenglycol on the presence of NaCl in it within the range of its concentrations from 0 to 4% and methanol in the concentration range of 0-20 g/l follow the noncompetitive inhibition equation. When NaCl concentration in the medium is more than 4%, complete separation of constructive and energy metabolism processes is observed.