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Growth Characteristics (growth + characteristic)
Selected AbstractsUniform Amplification of Phage with Different Growth Characteristics in Individual Compartments Consisting of Monodisperse Droplets,ANGEWANDTE CHEMIE, Issue 31 2010Ratmir Derda Dr. Jeder Klon zählt! Beim Phagen-Display gehen Klone, die das Phagenwachstum hemmende Liganden präsentieren, bei der Vervielfältigung verloren. In monodispersen Emulsionen, die mithilfe eines einfachen Mikrofluidiksystems erzeugt wurden, ist die Konkurrenz zwischen langsam (S) und schnell (R) wachsenden Phagen abgemildert, sodass das R/S-Verhältnis beibehalten bleibt. Die konkurrenzfreie Vervielfältigung von Phagen bewahrt Liganden, die im normalen Phagen-Display abhanden kommen. [source] Growth characteristics of Bacillus subtilis (natto) in milkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2010YUTAKA KITAMURA In this paper, Bacillus subtilis (natto) was incubated to develop a possible functional ingredient in ice cream. A lab-scale culture revealed that incubation in the sterilised milk without dilution and concentration at 37°C for 28 h could obtain ideal growth characteristics of Bacillus subtilis (natto), especially with continuous aeration. Following freezing operation of the cultured milk, survival content of Bacillus subtilis (natto) was at 49,92%, while nattokinase activity was conserved at 62,98% comparing with the initial contents, which indicating a potential for application of natto functional ingredient in frozen milk products. [source] Prostate carcinoma cells selected by long-term exposure to reduced oxygen tension show remarkable biochemical plasticity via modulation of superoxide, HIF-1, levels, and energy metabolismJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2007Jeanne Bourdeau-Heller Cancer cells are able to tolerate levels of O2 that are damaging or lethal to normal cells; we hypothesize that this tolerance is the result of biochemical plasticity which maintains cellular homeostasis of both energy levels and oxidation state. In order to examine this hypothesis, we used different O2 levels as a selective agent during long-term culture of DU145 prostate cancer cells to develop three isogenic cell lines that grow in normoxic (4%), hyperoxic (21%), or hypoxic (1%) O2 conditions. Growth characteristics and O2 consumption differed significantly between these cell lines without changes in ATP levels or altered sensitivity to 2-deoxy- D -glucose, an inhibitor of glycolysis. O2 consumption was significantly higher in the hyperoxic line as was the level of endogenous superoxide. The hypoxic cell line regulated the chemical gradient of the proton motive force (PMF) independent of the electrical component without O2 -dependent changes in Hif-1, levels. In contrast, the normoxic line regulated Hif-1, without tight regulation of the chemical component of the PMF noted in the hypoxic cell line. From these studies, we conclude that selection of prostate cancer cells by long-term exposure to low ambient levels of O2 resulted in cells with unique biochemical properties in which energy metabolism, reactive oxygen species (ROS), and HIF-1, levels are modulated to allow cell survival and growth. Thus, cancer cells exhibit remarkable biochemical plasticity in response to various O2 levels. J. Cell. Physiol. 212:744,752, 2007. © 2007 Wiley-Liss, Inc. [source] d -Alanyl ester depletion of teichoic acids in Lactobacillus reuteri 100-23 results in impaired colonization of the mouse gastrointestinal tractENVIRONMENTAL MICROBIOLOGY, Issue 7 2007Jens Walter Summary The dlt operon of Gram-positive bacteria encodes proteins required for the incorporation of d -alanine esters into cell wall-associated teichoic acids (TA). d -Alanylation of TA has been shown to be important for acid tolerance, resistance to antimicrobial peptides, adhesion, biofilm formation, and virulence of a variety of pathogenic organisms. The aim of this study was to determine the importance of d -alanylation for colonization of the gastrointestinal tract by Lactobacillus reuteri 100-23. Insertional inactivation of the dltA gene resulted in complete depletion of d -alanine substitution of lipoteichoic acids. The dlt mutant had similar growth characteristics as the wild type under standard in vitro conditions, but formed lower population sizes in the gastrointestinal tract of ex- Lactobacillus -free mice, and was almost eliminated from the habitat in competition experiments with the parental strain. In contrast to the wild type, the dlt mutant was unable to form a biofilm on the forestomach epithelium during gut colonization. Transmission electron microscope observations showed evidence of cell wall damage of mutant bacteria present in the forestomach. The dlt mutant had impaired growth under acidic culture conditions and increased susceptibility to the cationic peptide nisin relative to the wild type. Ex vivo adherence of the dlt mutant to the forestomach epithelium was not impaired. This study showed that d -alanylation is an important cell function of L. reuteri that seems to protect this commensal organism against the hostile conditions prevailing in the murine forestomach. [source] Effects of maternal smoking in pregnancy on prenatal brain development.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2007The Generation R Study Abstract Nicotine, as has been shown in animal studies, is a neuroteratogen, even in concentrations that do not cause growth retardation. In humans, there is only indirect evidence for negative influences of nicotine on brain development from studies on the association between maternal smoking in pregnancy and behavioural and cognitive development in the offspring. We investigated the associations of maternal smoking in pregnancy with foetal head growth characteristics in 7042 pregnant women. This study was embedded in the Generation R Study, a population-based prospective cohort study from foetal life until adulthood. Maternal smoking was assessed by questionnaires in early, mid- and late pregnancy. Head circumference, biparietal diameter, transcerebellar diameter and atrial width of lateral ventricles were repeatedly measured by ultrasound. When mothers continued to smoke during pregnancy, foetal head circumference showed a growth reduction of 0.13 mm [95% confidence interval (CI): ,0.18, ,0.09] per week compared to foetuses of mothers who never smoked during pregnancy. Biparietal diameter of foetuses with smoking mothers grew 0.04 mm (95% CI: ,0.05, ,0.02) less per week than that of foetuses of nonsmoking mothers. Atrial width of lateral ventricle was 0.12 mm (95% CI: ,0.22, ,0.02) smaller and transcerebellar diameter was 0.08 mm (95% CI: ,0.15, ,0.00) smaller if mothers smoked, but growth per week of these characteristics was not affected by maternal smoking in pregnancy. In conclusion, continuing to smoke during pregnancy leads to reduced growth of the foetal head. Further research should focus on the causal pathway from prenatal cigarette exposure via brain development to behavioural and cognitive functions. [source] Salinity as a structuring factor for the composition and performance of bacterioplankton degrading riverine DOCFEMS MICROBIOLOGY ECOLOGY, Issue 2 2003Silke Langenheder Abstract The impact of salinity on the composition and functional performance (biomass production, growth efficiency and growth rates) of bacterial communities was investigated using batch cultures growing on dissolved organic carbon from a river draining into the Northern Baltic Sea. The cultures were adjusted to riverine or estuarine salinity levels and inoculated with bacteria from these two environments. Bacterial growth efficiencies differed in response to salinity and the origin of the inoculum. When salinity was adjusted to correspond to the salinity at the site where the inoculum was retrieved, growth efficiency was relatively high (11.5±2.6%). However, when bacteria were confronted with a shift in salinity, growth efficiency was lower (7.5±2.0%) and more of the utilized carbon was respired. In contrast, growth rates were higher when bacteria were exposed to a change in salinity. The composition of the bacterial communities developing in the batch cultures differed, as shown by 16S rDNA DGGE, depending on the origin of the inoculum and salinity. Reverse and direct DNA,DNA hybridization revealed salinity optima in the growth of specific bacterial strains as well as broader phylogenetic groups. Strains belonging to the ,- and ,- Proteobacteria, Actinobacteria and ,- Proteobacteria other than the genus Pseudomonas showed higher relative abundance under freshwater conditions, whereas strains of the genus Pseudomonas and the Cytophaga,Flavobacterium,Bacteroides group were favored by estuarine conditions. Generally, our results demonstrate functional changes associated with changes in community composition. We suggest that even moderate changes in salinity affect bacterial community composition, which subsequently leads to altered growth characteristics. [source] Light-Emitting Rubrene Nanowire Arrays: A Comparison with Rubrene Single CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Jin Woo Lee Abstract This is a report on a new method of growth of a light-emitting rubrene nanowires array with diameters of 200,±,10,nm by using organic vapor transport through Al2O3 nanoporous templates. Nanometer-scale laser confocal microscope (LCM) photoluminescence (PL) spectra and crystalline structures of the rubrene nanowires are compared with those of rubrene single crystals prepared with the same experimental conditions without the template. In the LCM PL spectra it is observed that the PL spectra and intensity varies with the detecting positions because of the crystal growth characteristics of the rubrene molecules. A single rubrene nanowire has a wider LCM PL band width than that of the rubrene single crystal. This may originate from the light emissions of the mixed polarized bands due to additional new crystallinity in the formation of the nanowires. From the current,voltage characteristic curves, the semiconducting nature of both the rubrene nanowires and single crystals is observed. [source] Development and growth characteristics of Caucasian and white clover seedlings, compared with perennial ryegrassGRASS & FORAGE SCIENCE, Issue 4 2006A. D. Black Abstract Seedling competition for resources during establishment affects the potential success of individual species within a pasture. Germination, emergence and leaf expansion are key characteristics that contribute to the competitive ability of species. In this study, development and growth characteristics of Caucasian clover, white clover and perennial ryegrass (PRG) seedlings were quantified. A base temperature of <4°C and an optimum temperature of ,27°C were found for development in each species. Thermal time (Tt) requirements for 75% of final germination were lower for Caucasian clover (46°C d) and white clover (40°C d) than for PRG (76°C d), but Tt requirements for 50% of final emergence were similar (,110°C d). The phyllochron (°C d leaf,1) for primary stem leaves was slower for Caucasian clover (109°C d) than for white clover (94°C d) and PRG (101°C d). Appearance of the first PRG tiller, which indicates the initiation of secondary leaf development, occurred after 373°C d, compared with 532°C d for the first white clover stolon. Caucasian clover crown shoots did not develop until >1180°C d. Consequently, white clover and PRG had more leaves (,15 plant,1) and faster shoot relative growth rates (,0·062 mg mg,1 d,1) than Caucasian clover (5 leaves plant,1, 0·049 mg mg,1 d,1). [source] Growth characteristics of Bacillus subtilis (natto) in milkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2010YUTAKA KITAMURA In this paper, Bacillus subtilis (natto) was incubated to develop a possible functional ingredient in ice cream. A lab-scale culture revealed that incubation in the sterilised milk without dilution and concentration at 37°C for 28 h could obtain ideal growth characteristics of Bacillus subtilis (natto), especially with continuous aeration. Following freezing operation of the cultured milk, survival content of Bacillus subtilis (natto) was at 49,92%, while nattokinase activity was conserved at 62,98% comparing with the initial contents, which indicating a potential for application of natto functional ingredient in frozen milk products. [source] Adaptive radiation into ecological niches with eruptive dynamics: a comparison of tenthredinid and diprionid sawfliesJOURNAL OF ANIMAL ECOLOGY, Issue 3 2005PETER W. PRICE Summary 1We tested the hypothesis that the bottom-up influence of coniferous plant resources promotes the probability of outbreak or eruptive dynamics in sawflies. The literature was examined for three geographical regions , North America north of Mexico, Europe and Japan. 2In each region tenthredinid sawflies (Hymenoptera: Tenthredinidae) were significantly more likely to be eruptive on conifers than on angiosperms. 3The diprionid sawflies (Hymenoptera: Diprionidae) that attack conifers exclusively showed a significantly higher probability of eruptive dynamics than the tenthredinid sawflies on angiosperms in two regions, North America and Europe, and in Japan the trend was in the same direction. 4The probability of species showing eruptive dynamics on coniferous hosts was not significantly different among tenthredinids and diprionids on conifers in North America, Europe and Japan. 5The weight of evidence supports the hypothesis of conifers supporting a higher percentage of eruptive species than angiosperms. 6In the adaptive radiation of tenthredinid sawflies from flowering plants onto conifers, larches (Larix) appear to be particularly favourable for colonization, but pines (Pinus) have not been colonized in any region, a pattern likely to be explained by the growth characteristics of the host plants. 7Among tenthredinid species in Europe, where sawfly/host relationships are best known, there is a significant trend for an increasing proportion of outbreaking species from herbs, to shrubs, to trees. 8The results indicate for the first time the strong bottom-up effects of plant resources on the population dynamics of sawflies, involving general features of host plant taxa and growth characteristics. [source] Age-based life history parameters and status assessments of by-catch species (Lethrinus borbonicus, Lethrinus microdon, Pomacanthus maculosus and Scolopsis taeniatus) in the southern Arabian GulfJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2010E. Grandcourt Summary Life history and demographic parameters for Lethrinus borbonicus, Lethrinus microdon, Pomacanthus maculosus and Scolopsis taeniatus in the southern Arabian Gulf were estimated using a combination of size frequency, biological and size-at-age data. Defined structural increments consisting of alternating translucent and opaque bands in transverse sections of sagittal otoliths were validated as annuli. The maximum age estimates ranged from 5 years for Scolopsis taeniatus to 36 years for Pomacanthus maculosus. The size-at-age relationships were highly asymptotic in form with the majority of growth being achieved early in life. There were significant differences in the growth characteristics between sexes for Pomacanthus maculosus, with males approaching a larger asymptotic size at a faster rate than females. With the exception of Scolopsis taeniatus, the mean age at which fish became vulnerable to capture was lower than the mean age at first sexual maturity. The stocks of L. microdon, P. maculosus and S. taeniatus were exploited within sustainable limits, conversely, L. borbonicus was found to be overexploited and recruitment overfishing may have occurred as the relative spawner biomass per recruit was below 30% of the unexploited state. [source] The role of host organism, transcriptional switches and reporter mechanisms in the performance of Hg-induced biosensorsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004M. Harkins Abstract Aims:, The purpose of this study was to comprehensively compare the response of nine biosensors capable of being induced by Hg. Induction by Hg was based upon the insertion of merR, merB, zntA and zntR promoter genes. LuxCDABE or lucFF reporter genes expressed luminescence, and host organisms were Escherichia coli, Vibrio anguillarum and Pseudomonas fluorescens. The role of transcriptional switches, reporter mechanism and host organism was to be investigated. Methods and Results:, All biosensors were subjected to the same assay conditions. Sensors had their own individual growth characteristics and response to the doses of Hg tested. Maximum bioluminescence response was induced by concentrations of Hg between 2·5 nm and 5 ,m. E. coli pRB28 was found to detect levels of Hg as low as 1·6 nm and yet was capable of operating in a concentration range of up to 12·5 ,m. Conclusions:, The response of the sensors demonstrated their suitability for analysis under environmentally relevant concentrations. The sensitivity of the sensors, the optimum range and the expediency of the assay could not be related to a single sensor trait. It may be concluded that biosensor performance is dependent on more than one of the single factors studied. Significance and Impact of the Study:, The results show that comparative testing of sensors is an important step in evaluating the relevance and performance of biosensors prior to routine environmental application. [source] Physiological characterization of Mycobacterium sp. strain 1B isolated from a bacterial culture able to degrade high-molecular-weight polycyclic aromatic hydrocarbonsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2004C.E. Dandie Abstract Aim:, The aim of this study was to further characterize a bacterial culture (VUN 10,010) capable of benzo[a]pyrene cometabolism. Methods and Results:, The bacterial culture, previously characterized as a pure culture of Stenotrophomonas maltophilia (VUN 10,010), was found to also contain another bacterial species (Mycobacterium sp. strain 1B), capable of degrading a similar range of PAH substrates. Analysis of its 16S rRNA gene sequence and growth characteristics revealed the strain to be a fast-growing Mycobacterium sp., closely related to other previously isolated PAH and xenobiotic-degrading mycobacterial strains. Comparison of the PAH-degrading characteristics of Mycobacterium sp. strain 1B with those of S. maltophilia indicated some similarities (ability to degrade phenanthrene and pyrene), but some differences were also noted (S. maltophilia able to degrade fluorene, but not fluoranthene, whereas Mycobacterium sp. strain 1B can degrade fluoranthene, but not fluorene). Unlike the S. maltophilia culture, there was no evidence of benzo[a]pyrene degradation by Mycobacterium sp. strain 1B, even in the presence of other PAHs (ie pyrene) as co-metabolic substrates. Growth of Mycobacterium sp. strain 1B on other organic carbon sources was also limited compared with the S. maltophilia culture. Conclusions:, This study isolated a Mycobacterium strain from a bacterial culture capable of benzo[a]pyrene cometabolism. The Mycobacterium strain displays different PAH-degrading characteristics to those described previously for the PAH-degrading bacterial culture. It is unclear what role the two bacterial strains play in benzo[a]pyrene cometabolism, as the Mycobacterium strain does not appear to have endogenous benzo[a]pyrene degrading ability. Significance and Impact of the Study:, This study describes the isolation and characterization of a novel PAH-degrading Mycobacterium strain from a PAH-degrading culture. Further studies utilizing this strain alone, and in combination with other members of the consortium, will provide insight into the diverse roles different bacteria may play in PAH degradation in mixed cultures and in the environment. [source] Activation of P44/42 Map Kinases within Human Epidermal Neoplasia.JOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005Bryon Jackson Squamous cell carcinoma (SCC) arises from a series of genetic changes that form a clone of keratinocytes with enhanced growth characteristics. The p44/42 Map kinase pathway is a highly conserved growth regulatory pathway that helps relay critical signals from the cell membrane to the nucleus. Evidence demonstrating activation of the p44/42 pathway in the human cutaneous SCC has not been established. This study examined if p44/42 MAP kinase is activated in lesions of keratinocytic neoplasia. Lesions from the defined stages of keratinocytic neoplasia, normal skin, actinic keratoses, squamous cell carcinoma in situ, and squamous cell carcinoma, were randomly selected from archived material and studied. Antibodies that detect human p44/42 (phosphorylated and unphosphorylated) and only phosphorylated, activated, human p44/42 were used. The intensity and prevalence of cytoplasmic and nuclear staining was evaluated in the lesional cells. The results suggest that there is a not a simple linear relationship between the amount of nuclear staining and the type of lesion. The results show that there was a significant increase in the level of nuclear phosphorylated p44/42 staining progressing from an actinic keratoses to a sqaumous cell carcinoma in situ. These findings suggest that p44/42 MAP kinases are activated in keratinocytic neoplasia. [source] PRODUCTION AND RELEASE OF GEOSMIN BY THE CYANOBACTERIUM OSCILLATORIA SPLENDIDA ISOLATED FROM A PHOENIX WATER SOURCEJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Hu, Q.1, Sommerfeld, M.1 Lowry, D.1, Dempster, T.1, Westerhoff, P.2, Baker, L.3, Bruce, D. & Nguyen, M. L.2 1Department of Plant Biology and 2Department of Civil and Environmental Engineering, Arizona State University, Tempe, Arizona 85287; 3Baker Environmental Consulting, 8001 Greenwood Drive, Moundview, MN 55112 Geosmin is a common component of the off-flavors detected in the drinking water supply sources of metropolitan Phoenix (Arizona). A cyanobacterium, Oscillatoria splendida, was isolated from source water during incidents of elevated geosmin production and was implicated as a cause of earthy/musty off-flavors in the drinking water. Production of geosmin was found to be constitutive in O. splendida during all growth stages. Effects of environmental parameters on the growth characteristics, and on production and release of geosmin by O. splendida, was studied under laboratory conditions. The specific growth rate and cell-bound geosmin increased with increasing temperature from 12 to 26 °C, the range of water temperatures that occur in the drinking water supply. On a per-chlorophyll a basis, however, more geosmin was released from the cells at lower temperatures. An inverse relationship was evident between light intensity and O. splendida growth and the release of geosmin. Cell-bound geosmin, however, was higher at higher light intensities. Dark incubation initially stimulated the biosynthesis of geosmin, whereas a prolonged period of darkness (2-3 weeks) resulted in massive release of geosmin into the culture medium from lysis and cellular decomposition. Dissolved nitrogen appeared to be the limiting nutrient for O. splendida in the local water supply source. When nitrate was added to laboratory cultures, both growth and geosmin production increased. These results will be discussed in context with episodes of off-flavors in drinking waters in metropolitan Phoenix, Arizona. [source] Effect of prebiotics on viability and growth characteristics of probiotics in soymilkJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2010Siok-Koon Yeo Abstract BACKGROUND: Soy products have attracted much attention lately as carriers for probiotics. This study was aimed at enhancing the growth of probiotics in soymilk via supplementation with prebiotics. RESULTS:Lactobacillus sp. FTDC 2113, Lactobacillus acidophilus FTDC 8033, Lactobacillus acidophilus ATCC 4356, Lactobacillus casei ATCC 393, Bifidobacterium FTDC 8943 and Bifidobacterium longum FTDC 8643 were evaluated for their viability and growth characteristics in prebiotic-supplemented soymilk. In the presence of fructooligosaccharides (FOS), inulin, mannitol, maltodextrin and pectin, all strains showed viability exceeding 7 log10 colony-forming units mL,1 after 24 h. Their growth was significantly (P < 0.05) increased on supplementation with maltodextrin, pectin, mannitol and FOS. Additionally, supplementation with FOS, mannitol and maltodextrin increased (P < 0.05) the production of lactic acid. Supplementation with FOS and maltodextrin also increased the ,-galactosidase activity of probiotics, leading to enhanced hydrolysis and utilisation of soy oligosaccharides. Finally, prebiotic supplementation enhanced the utilisation of simpler sugars such as fructose and glucose in soymilk. CONCLUSION: Supplementation with prebiotics enhances the potential of soymilk as a carrier for probiotics. Copyright © 2009 Society of Chemical Industry [source] Experiments on growth interactions between two invasive macrophyte speciesJOURNAL OF VEGETATION SCIENCE, Issue 1 2004Marie-Hélène Barrat-Segretain Tutin et al. (1980) Abstract. The success of invasive species has been attributed to the ability to displace other species by direct competition. We studied growth and possible competition between the two macrophyte species Elodea nuttallii and E. canadensis, because the former has been observed to replace the latter in the field. Additional experiments were conducted in aquaria with mixed plantings of Elodea species. Species growth was measured and competitive abilities of each species determined by applying the reciprocal yield model to mean plant weight and length. In monocultures the growth rates of the two species were similar, while in mixtures the growth rate of E. canadensis was significantly lower than that of E. nuttallii. E. canadensis was more sensitive to intraspecific than to interspecific neighbours, whereas E. nuttallii was indifferent to the presence of neighbours. Differential growth characteristics of Elodea species can explain the displacement of E. canadensis by E. nuttallii under eutrophic field conditions. [source] Shaking alone, without concurrent aeration, affects the growth characteristics of Escherichia coliLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2007M.A. Juergensmeyer Abstract Aims:, This study investigated the effects of linear vibration on cultures grown in both hard- and soft-sided containers to determine whether vibration alone affected the growth rate. Methods and Results:, Cultures of Escherichia coli were exposed to vibrational acceleration with and without access to additional oxygen. Vibrated cultures grown in hard-sided containers exited lag phase earlier and had a higher final yield than identical unshaken cultures, whether or not the cultures had access to ambient air. Cultures grown in soft-sided containers showed no response to vibration. Conclusions:, Vibration in hard-sided containers decreases the length of the lag phase and increases final OD in E. coli, with or without increased oxygenation. Increased mixing and improved suspension, which result from vibration of cultures in hard-sided containers, are the most likely physical mechanisms for the more favorable culture conditions. Significance and Impact of the Study:, This paper demonstrates that growth enhancement of shaken cultures is a function of the rigidity of the vessel even without aeration of the medium. [source] Putative lipoproteins identified by bioinformatic genome analysis of Leifsonia xyli ssp. xyli, the causative agent of sugarcane ratoon stunting diseaseMOLECULAR PLANT PATHOLOGY, Issue 1 2007IAIN C. SUTCLIFFE SUMMARY Leifsonia xyli ssp. xyli is the causative agent of ratoon stunting disease, a major cause of economic loss in sugarcane crops. Understanding of the biology of this pathogen has been hampered by its fastidious growth characteristics in vitro. However, the recent release of a genome sequence for this organism has allowed significant novel insights. Further to this, we have performed a bioinformatic analysis of the lipoproteins encoded in the L. xyli genome. These analyses suggest that lipoproteins represent c. 2.0% of the L. xyli predicted proteome. Functional analyses suggest that lipoproteins make an important contribution to the physiology of the pathogen and may influence its ability to cause disease in planta. [source] Effect of temperature and soluble reactive phosphorus on abundance of Aphanizomenon flos-aquae (Cyanophyceae)PHYCOLOGICAL RESEARCH, Issue 1 2000Keishi Takano SUMMARY Filament density of Aphanizomenon flos-aquae (Lemmerm.) Ralfs, water temperature and soluble reactive phosphorus (SRP) were measured from April to August in 1993,1996 in Lake Barato, Hokkaido, Japan. In addition, growth characteristics and internal phosphorus (P) utilization of Aph. flos-aquae were evaluated under P limitation at three temperatures (15, 20 and 25,C) to clarify the role of internal accumulated P for its growth in the incubation experiment. The filament density was highest in early July 1994, when SRP concentration had not yet decreased and the water temperature was high. These are important factors favoring an increase in abundance of this species in L. Barato. During batch culture, the time course of the stationary phase was shortest at 25,C and longest at 15,C; the cellular C:P molar ratio was 111 under P sufficiency and increased eight- to 12-fold under P limitation. As the C:P ratio was significantly higher in the decreasing phase at 15,C, Aph. flos-aquae may be more adaptable to Plimitation at 15,C than at 20,C and 25,C. However, the low temperatures did not favor the abundance of Aph. flos-aquae in 1996. This indicates that the filament density of Aph. flos-aquae decreases before it reaches the maximum value for some reason under P limitation in L. Barato. [source] Enhancing plant growth and fiber production by silencing GA 2-oxidasePLANT BIOTECHNOLOGY JOURNAL, Issue 4 2010Jonathan Dayan Summary Enhancing plant height and growth rates is a principal objective of the fiber, pulp, wood and biomass product industries. Many biotechnological systems have been established to advance that task with emphasis on increasing the concentration of the plant hormone gibberellin, or on its signalling. In this respect, the most studied gibberellin biosynthesis enzyme is the GA 20-oxidase which catalyses the rate limiting step of the pathway. Overexpression of the gene resulted in an excessively high activity of the gibberellin deactivating enzyme, GA 2-oxidase. Consequently, this feedback regulation limits the intended outcome. We assume that silencing GA 2-oxidase transcription would abolish this antithetical effect, thereby allowing greater gibberellin accumulation. Here, we show that silencing the gibberellin deactivating enzyme in tobacco model plants results in a dramatic improvement of their growth characteristics, compared with the wild type and GA 20-oxidase over-expressing plants. Moreover, the number of xylem fiber cells in the silenced lines exceeded that of GA 20-oxidase over-expressing plants, potentially, making GA 2-oxidase silencing more profitable for the wood and fiber industries. Interestingly, crossing GA 20-oxidase over-expressing plants with GA 2-oxidase silenced plants did not yield consequential additive effects. Our findings unveil the benefits of silencing GA 2-oxidase to substantially increase tobacco growth and fiber production, which suggest using this approach in cultivated forest plantations and industrial herbaceous plants, worldwide. [source] Variation in virus populations and growth characteristics of two sugarcane cultivars naturally infected by Sugarcane yellow leaf virus in different geographical locationsPLANT PATHOLOGY, Issue 5 2007Y. Abu Ahmad Two sugarcane cultivars (R570 and SP71-6163) naturally infected by Sugarcane yellow leaf virus (SCYLV) were each imported from several geographical locations into a sugarcane yellow leaf-free environment (Montpellier, France). Plants were grown as plant cane for 5,6 months and the experiment was repeated for three consecutive years (2003,2005) in a greenhouse. Several sugarcane-growth and disease characteristics were monitored to identify variation in pathogenicity of SCYLV. Depending on their geographical origin, sugarcane cvs R570 and SP71-6163 were infected by SCYLV genotypes BRA-PER or REU, or a mixture of the two. Severity of symptoms did not vary between plants of cv. R570, but variation in disease severity between plants of cv. SP71-6163 from different geographical locations suggested the occurrence of pathogenic variants of SCYLV. For each sugarcane cultivar, differences in stalk length, number of stalk internodes, virus titre in the top visible dewlap leaf, and percentage of infection of leaf and stalk phloem vessels were also found between plants from different geographical origins. However, these differences were not always reproducible from one year to another, suggesting occurrence of different plant responses to SCYLV isolates under varying environmental conditions. [source] Effect of banana bunchy top virus infection on morphology and growth characteristics of bananaANNALS OF APPLIED BIOLOGY, Issue 1 2008C.R.R. Hooks Abstract Field experiments were conducted in Oahu, Hawaii, to investigate the effects of banana bunchy top virus (BBTV) infection on growth and morphology of banana (Musa acuminata). The time interval between aphid inoculation of BBTV and the initial appearance of disease symptoms (i.e. incubation period) was also determined. Plants infected with BBTV showed a significant reduction in petiole size (i.e. length and distance), plant canopy and height, leaf area, pseudostem diameter and chlorophyll content compared with control plants. Growth differences between virus-infected and control plants were not observed until 40,50 days after the plants were inoculated with viruliferous aphids. Other growth parameters such as petiole width and leaf production were not statistically different between infected and control plants. The incubation period of banana bunchy top disease or appearance of symptoms ranged from 25 to 85 days after aphid inoculation. However, PCR assays provided earlier detection of BBTV in banana plants compared with visual symptoms. [source] Carbon-nitrogen-phosphorus removal and biofilm growth characteristics in an integrated wastewater treatment system involving a rotating biological contactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Angelo H. Cabije Abstract A new rotating biological contactor-packed media technology (RBC-PMT) is locally innovated using light polyethylene Amazon screen material as disc media. A single-stage co-current fed of this type, which is connected with a series of equalization tanks as an integrated wastewater treatment system (IWWTS), showed good carbon-nitrogen-phosphorus (C-N-P) removal and unveiled biofilm growth characteristics noteworthy for treating pollutants in wastewater. The equalization tanks approached facultative anaerobic conditions while the RBC-PMT exhibited a completely aerated system, both with a slightly alkaline pH, whose temperatures are ranging from 21 to 24 °C, and both performed as biological nutrient removal systems. The combined nutrient removal efficiency at high organic loading rate (HOLR) and low organic loading rate (LOLR) showed fair chemical oxygen demand (COD) removal at 65.68 and 67.89%, respectively. Nitrate-nitrogen removal demonstrated good removal at 79.17% at HOLR and 83.43% at LOLR. There was excellent phosphate-phosphorus removal determined at 91.64 and 94.35% at high and low OLRs, respectively. This indicates that increasing the organic loading rate decreases the C-N-P removal in the IWWTS. Biofilm growth was characterized by the selection and survival of microorganisms present under aerobic environmental conditions in the RBC-PMT system and their respective metabolism in removing C-N-P substrates. Yeasts, coliform bacteria particularly E. coli, Cyanobacteria, and benthic diatoms were dominant microorganisms found upon oil-immersion microscopy. Protozoans and algae including Chlorococcum, Chlorella, Diatoma, Tribonema, Oscillatoria, Euglena, and other motile rotifiers were also dominantly found in the biofilm samples. Biofilm growth is observed and its average thickness was measured to be 7.71 µm at HOLR and 2.81 µm at LOLR. Thicker biofilm at HOLR has caused the reduced rate of diffusion of the microorganisms and their metabolic products as manifested by the low C-N-P removal during HOLR. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] The successful management of two pregnancies with wild type metastatic gastrointestinal stromal tumorsASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 3 2009Thean Hsiang TAN Abstract Aim: To discuss the management of the uncommon situation of metastatic gastrointestinal tumour coexisting with pregnancy. Method: We describe two cases of women with metastatic gastrointestinal stromal tumor (GIST) who successfully achieved a full-term pregnancy without complications and with the delivery of healthy infants. In both cases, treatment with imatinib mesylate was withheld during pregnancy because of its unknown effects and questionable safety for the developing fetus. The available data in the medical literature regarding the use and safety of imatinib and pregnancy are reviewed. We also examine whether the knowledge of the exon mutational status would have influenced treatment decisions. Results: Both women had wild type GIST, but with different tumor growth characteristics, treatment responses and outcomes. The first patient deferred imatinib therapy to fall pregnant and her disease progressed rapidly off treatment. The second patient had a more indolent GIST where active surgical management allowed her to experience a long durable clinical response. She potentially belongs to a pediatric subgroup which carries a better prognosis despite being off imatinib. Conclusion: While we have successfully managed two pregnant women with metastatic GIST, the issue of initiating imatinib therapy in treatment-naive women, and treatment interruption in women already on therapy, remain difficult areas. Patients and their partners need to make an informed choice regarding the associated risks and the potential long-term sequelae if pregnancies are contemplated. Further research into the natural history of wild type GIST and how to tailor subsequent treatment are needed. [source] Effects of a 50 Hz sinusoidal magnetic field on cell adhesion molecule expression in two human osteosarcoma cell lines (MG-63 and Saos-2)BIOELECTROMAGNETICS, Issue 5 2003Maria Teresa Santini Abstract The possibility that a sinusoidal 50 Hz magnetic field with a magnetic flux density of 0.5 mT can induce variations in the expression of cell adhesion molecules (CAMs) in two human osteosarcoma cell lines (MG-63 and Saos-2) was investigated. In particular, the expression of two important integrins, VLA-2, the receptor for collagen, and VLA-5, the receptor for fibronectin, as well as CD44, were examined in both cell lines after these had been exposed for 7 and 14 days to a 50 Hz, 0.5 mT field. Cell surface morphology (scanning electron microscopy), cell growth characteristics (growth curves and cell cycle phase distribution), and cell death (necrosis and apoptosis) were also examined. The results demonstrate that no variations in surface morphology and cell death occurred between control and exposed cells in both MG-63 and Saos-2 cells, while significant changes were noted in cell growth and fibronectin and CD44 expression in MG-63 cells. The results are discussed in view of the important role that CAMs play in controlling various cancer cell functions, particularly proliferation and metastasis. Bioelectromagnetics 24:327-338, 2003. © 2003 Wiley-Liss, Inc. [source] Establishment and characterization of seven human renal cell carcinoma cell linesBJU INTERNATIONAL, Issue 1 2000K.-H. Shin Objective,To establish human renal cell carcinoma (RCC) cell lines, and to investigate the cell phenotypes and molecular characteristics of human RCC cell lines and their corresponding tumour tissues. Materials and methods,Seven human RCC cell lines from pathologically proven RCCs were established. The histopathology of the primary tumours, in vitro growth characteristics and status of tumour suppressor genes, mismatch repair genes and microsatellite instability (MSI) were examined in cell lines and their corresponding tumour tissues. Five of the cell lines were derived from clear cells (SNU-228, -267, -328, -349, and -1272), one from granular cells (SNU-482), and one from mixed clear and granular cell types (SNU-333). The mutational status was compared for von Hippel-Lindau (VHL), p53, TGF-, type II receptor (TGF-,RII), hMSH2, and hMLH1 genes in the cell lines and their corresponding tumour tissues. The MSI status of the cell lines was determined by screening for adenine repeat sequences, e.g. BAT-25, BAT-26, and BAT-40. Results,All lines showed different doubling times and were confirmed by DNA fingerprinting analysis to be unique. Contamination by mycoplasma or bacteria was excluded. In two cell lines (SNU-349 and -1272) and their tumour tissues, mutations in the VHL gene were found. The SNU-267 line had a frameshift mutation in the p53 gene. A missense mutation of the TGF-,RII gene was detected in the SNU-1272 line and the corresponding tissue. Analysis of the repeat sequences showed one cell line (SNU-349) to have MSI and the other six to have microsatellite stability. As MSI is a hallmark of the inactivation of mismatch repair genes, the presence of hMSH2 and hMLH1 mutations was investigated in all seven cell lines. An inactivating homozygous single base-pair deletion of the hMLH1 gene was found only in the SNU-349 cell line and corresponding tissue. Moreover, a frameshift mutation within an 8-bp polyadenine repeat present in the hMSH3 coding region was found only in the MSI cell line and tumour tissue. Conclusion,These newly established RCC cell lines should provide a useful in vitro model for studies related to human RCC. The SNU-349 cell line should be especially useful for studies of MSI and mismatch repair-defective RCCs. [source] Mammary serine protease inhibitor inhibits epithelial growth factor-induced epithelial-mesenchymal transition of esophageal carcinoma cellsCANCER, Issue 1 2009Zhen Cai PhD Abstract BACKGROUND: By using proteomic technology, the authors previously observed the substantial down-regulation of mammary serine protease inhibitor (maspin) in esophageal squamous cell carcinoma and metastases. In the current study, they examined the effects of maspin re-expression in a maspin-null esophageal cancer cell line EC109 and also investigated the underlying mechanism. METHODS: A cell line with stable maspin expression was established. An epithelial growth factor (EGF)-induced epithelial-mesenchymal transition (EMT) model was used to mimic some aspects of the metastatic process in vitro. The effects of maspin reintroduction on EGF-induced EMT and cell growth characteristics were evaluated. Comparative proteomic analysis of transfected cells versus parental cells was then performed to explore the potential mechanism. RESULTS: The introduction of maspin into EC109 cells was able to inhibit EGF-induced EMT and altered cell growth characteristics, including the serum dependence, proliferative response to EGF stimulation, and colony formation ability in soft agar, indicating a conversion from a malignant phenotype to a benign phenotype. Proteomic analysis revealed a significant down-regulation of a group of glycolytic enzymes in maspin-transfected cells. In addition, maspin-transfected cells expressed much lower levels of hypoxia-inducible factor 1, than parental cells or empty vector transfected cells. CONCLUSIONS: Maspin exhibited a metastasis-suppressive effect, which may be a consequence of the reversal of the malignant phenotype of EC109 cells. The switch of cellular metabolic phenotype to low glycolysis by the gain of maspin function may play a key role in the process. This finding provides additional evidence of the tumor metastasis-suppressive activity of maspin and may indicate a new direction for future studies of the mechanism of maspin. Cancer 2009. © 2008 American Cancer Society. [source] Implications of a simple mathematical model to cancer cell population dynamicsCELL PROLIFERATION, Issue 1 2006A. L. Garner Many potential treatments preferentially interact with cells at certain stages of the cell cycle by either selective killing or halting the cell cycle, such as intense, nanosecond-duration pulsed electric fields (nsPEFs). Simple mathematical models of unfed cancer cell populations at the plateau of their growth characteristics may estimate the long-term consequences of these treatments on proliferating and quiescent cell populations. Applying such a model with no transition from the quiescent to proliferating state shows that it is possible for the proliferating cell population to fall below 1 if the quiescent cell population obtains a sufficient competitive advantage with respect to nutrient consumption and/or survival rate. Introducing small, realistic transition rates did not appreciably alter short-term or long-term population behaviour, indicating that the predicted small cell population behaviour (< 1 cell) is not an artefact of the simpler model. Experimental observations of nsPEF-induced effects on the cell cycle suggest that such a model may serve as a first step in assessing the viability of a given cancer treatment in vitro prior to clinical application. [source] | ||||||||||||||||||||||||||||||||||