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Physiological Characteristics (physiological + characteristic)
Selected AbstractsPhysiological characteristics of the biocontrol yeast Pichia anomala J121FEMS YEAST RESEARCH, Issue 3 2002Elisabeth Fredlund Abstract The yeast Pichia anomala J121 prevents mold spoilage and enhances preservation of moist grain in malfunctioning storage systems. Development of P. anomala J121 as a biocontrol agent requires in-depth knowledge about its physiology. P. anomala J121 grew under strictly anaerobic conditions, at temperatures between 3°C and 37°C, at pH values between 2.0 and 12.4, and at a water activity of 0.92 (NaCl) and 0.85 (glycerol). It could assimilate a wide range of C- and N-sources and produce killer toxin. A selective medium containing starch, nitrate, acetic acid, and chloramphenicol was developed for P. anomala. P. anomala was equally sensitive as Candida albicans to common antifungal compounds. Growth ability at a range of environmental conditions contributes to the competitive ability of the biocontrol yeast P. anomala J121. [source] Physiological characteristics of the body fluid in lymphedematous patients postbreast cancer surgery, focusing on the intracellular/extracellular fluid ratio of the upper limbJAPAN JOURNAL OF NURSING SCIENCE, Issue 1 2010Hiromi SAKUDA Abstract Aim:, The aim of this research was to determine the physiological characteristics of patients with lymphedema following breast cancer surgery, based on differences between the quantity of body water in the right and left fingertips, with a view to establishing whether or not this simple measurement could serve as a predictive index for the onset of lymphedema. Method:, The research was conducted at a hospital in Hiroshima, Japan (August 2004 to December 2004). Observations were made on 39 female breast cancer patients who had undergone surgery and 45 healthy female participants. Additional information was collected via interviews with the individual participants. The quantity of body water in all the participants was measured by using a bioimpedance spectrum analysis system. Comparisons of the intracellular/extracellular fluid ratios (I/Es) were made between the edema patients and the non-edema patients, with further testing being done between the affected and unaffected sides of the upper limb in the edema patients. Results:, In the edema patients, significant differences were recognized between the affected side's upper limb I/E and the unaffected side's upper limb I/E. In relation to the affected side's upper limb I/E of the edema patients, even when the mean value and standard deviation were included, the value did not exceed 1.0 and the mean , 3 SD value of the affected side's upper limb I/E in the non-edema patients was 1.04. Conclusions:, The results suggest that measurements of the affected and unaffected sides' upper limb I/E showed a potential for use as a reliable predictive index for lymphedema. [source] Physiological characteristics of selenite uptake by maize roots in response to different pH levelsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2010Lianhe Zhang Abstract In selenite solutions, H2SeO3, HSeO, and SeO<$>_3^{2-}<$> are in equilibrium in proportions that vary with solution pH. The physiological characteristics of selenite uptake were studied with excised roots of maize (Zea mays L.) seedlings at pH 3.0, 5.0, and 8.0. The results showed that 0.10 mM 2,4-dinitrophenol (DNP), 1.0 mM sodium fluoride (NaF), and a temperature of 4°C inhibited selenite uptake by maize roots by 16%, 20%, and 23% at pH 3.0, by up to 80%, 79%, and 78% at pH 5.0, and by 5%, 9%, and 16% at pH 8.0. Hence, selenite may enter roots at pH 5.0 in an energy-dependent manner, in contrast to pH 3.0 and 8.0. The uptake kinetics for selenite were determined for excised roots of maize, and the curves were linear at pH 3.0 and 8.0, but saturated at pH 5.0, showing that carrier-mediated uptake of selenite occurred at pH 5.0, but not at pH 3.0 or 8.0. Further studies showed that HgCl2 and AgNO3 inhibited selenite uptake separately by 81% and 76% at pH 3.0 and indicated that selenite was absorbed by maize roots through aquaporins at pH 3.0. At pH 8.0, anion-channel inhibitors only inhibited a small fraction of selenite uptake, indicating that the major absorption pathway of SeO<$>_3^{2-}<$> species into roots was not absorbed passively through anion channels, but might involve other processes. According to these results, it is proposed that selenite uptake occurs via different mechanisms depending on its species in solution in response to pH levels. [source] Effects of thymol and diphenyliodonium chloride against Campylobacter spp. during pure and mixed culture in vitroJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2009R.C. Anderson Abstract Aims:, To determine if the purported deaminase inhibitors diphenyliodonium chloride (DIC) and thymol reduce the growth and survivability of Campylobacter. Methods and Results:, Growth rates of Campylobacter jejuni and Camp. coli were reduced compared to unsupplemented controls during culture in Muellar,Hinton broth supplemented with 0·25 ,mol DIC or thymol ml,1 but not with 0·01 ,mol monensin ml,1 or 1% ethanol. Recovery of Camp. jejuni and Camp. coli was reduced >5 log10 CFU from controls after 24 h pure culture in Bolton broth supplemented with 0·25 or 1·0 ,mol DIC ml,1 or with 1·0 ,mol thymol ml,1. Similarly, each test Campylobacter strain was reduced >3 log10 CFU from controls after 24 h mixed culture with porcine faecal microbes in Bolton broth supplemented with 0·25 or 1·0 ,mol DIC ml,1 or with 1·0 ,mol thymol ml,1. Treatments with 0·25 ,mol thymol ml,1, 0·01 ,mol monensin ml,1 or 1% ethanol were less effective. Ammonia production during culture or incubation of cell lysates was reduced by 0·25 or 1·0 ,mol DIC ml,1 but only intermittently reduced, if at all, by the other treatments. Conclusions:, Diphenyliodonium chloride and thymol reduced growth, survivability and ammonia production of Camp. jejuni and Camp. coli. Significance and Impact of the Study:, Results suggest a potential physiological characteristic that may be exploited to develop interventions. [source] Growth in relation to microclimatic conditions and physiological characteristics of four Lobaria pulmonaria populations in two contrasting habitatsECOGRAPHY, Issue 1 2004Gisela Gaio-Oliveira The aim of the present study was to compare the physiological characteristics of various populations of the lichen Lobaria pulmonaria in Portugal and Sweden. For this, indirect markers of algal (photobiont) and fungal (mycobiont) activity were measured, as well as their CO2 gasexchange characteristics. Microclimatic conditions and the lichens growth performance in the two countries were compared using reciprocal transplantation. Two populations of L. pulmonaria represented each country: one collected from forest interior conditions and one from forest edge habitats. A non-transplanted "wild" population was also studied in each country, in order to evaluate any transplantation effects per se. The main hypothesis were that; 1) growth should be faster in Portugal due to higher light availability; 2) the energy use efficiency of lichen biomass gain should be similar for the native populations in their respective native habitat; 3) if the lichens were able to adapt to the environmental conditions in the foreign habitat this should be revealed as similar growth rates among all thalli transplanted at the same site, regardless of their origin. Physiologically, the Portuguese and Swedish populations were very similar, both concerning their CO2 gas exchange characteristics and distribution of resources between photo- and mycobiont tissue. Environmental conditions were more advantageous for L. pulmonaria growth in Portugal, i.e. higher photon flux densities and ambient temperatures when the lichens were wet and active, and a lower fraction of the active time occurring in darkness. However, despite similar physiological characteristics of all the studied populations, the Swedish lichens were not able to grow as well in Portugal as the native, while all populations had similarly low growth rates in Sweden. [source] Distribution, phylogenetic diversity and physiological characteristics of epsilon- Proteobacteria in a deep-sea hydrothermal fieldENVIRONMENTAL MICROBIOLOGY, Issue 10 2005Satoshi Nakagawa Summary Epsilon- Proteobacteria is increasingly recognized as an ecologically significant group of bacteria, particularly in deep-sea hydrothermal environments. In this study, we studied the spatial distribution, diversity and physiological characteristics of the epsilon- Proteobacteria in various microbial habitats in the vicinity of a deep-sea hydrothermal vent occurring in the Iheya North field in the Mid-Okinawa Trough, by using culture-dependent and -independent approaches. The habitats studied were inside and outside hydrothermal plume, and annelid polychaete tubes. In addition, we deployed colonization devices near the vent emission. The polychaete tubes harboured physiologically and phylogenetically diverse microbial community. The in situ samplers were predominantly colonized by epsilon -Proteobacteria. Energy metabolism of epsilon- Proteobacteria isolates was highly versatile. Tree topology generated from the metabolic traits was significantly different (P = 0.000) from that of 16S rRNA tree, indicating current 16S rRNA gene-based analyses do not provide sufficient information to infer the physiological characteristics of epsilon- Proteobacteria. Nevertheless, culturability of epsilon- Proteobacteria in various microbial habitats differed among the phylogenetic subgroups. Members of Sulfurimonas were characterized by the robust culturability, and the other phylogenetic subgroups appeared to lose culturability in seawater, probably because of the sensitivity to oxygen. These results provide new insight into the ecophysiological characteristics of the deep-sea hydrothermal vent epsilon- Proteobacteria, which has never been assessed by comparative analysis of the 16S rRNA genes. [source] Tonically active neurons in the primate striatum and their role in the processing of information about motivationally relevant eventsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2002Paul ApicellaArticle first published online: 11 DEC 200 Abstract Analysis of recordings of single neuronal activity in the striatum of monkeys engaged in behavioural tasks has shown that tonically active neurons (TANs) can be distinguished by their distinct spontaneous firing and functional properties. As TANs are assumed to be cholinergic interneurons, the study of their physiological characteristics allows us to gain an insight into the role of a particular type of local-circuit neuron in the processing of information at the striatal level. In monkeys performing various behavioural tasks, the change in the activity of TANs, unlike the diversity of task-related activations exhibited by the phasically active population of striatal neurons, involves a transient depression of the tonic firing related to environmental events of motivational significance. Such events include primary rewards and stimuli that have acquired a reward value during associative learning. These neurons also respond to an aversive air puff, indicating that their responsiveness is not restricted to appetitive conditions. Another striking feature of the TANs is that their responses can be modulated by predictions about stimulus timing. Temporal variations in event occurrence have been found to favour the responses of TANs, whereas the responses are diminished or abolished in the presence of external cues that predict the time at which events will occur. These data suggest that the TANs respond as do detectors of motivationally relevant events, but they also demonstrate that these neurons are influenced by predictive information based on past experience with a given temporal context. TANs represent a unique subset of striatal neurons that might serve a modulatory function, monitoring for temporal relationships between environmental events. [source] ,-Adrenoceptor gene variation and intermediate physiological traits: prediction of distant phenotypeEXPERIMENTAL PHYSIOLOGY, Issue 7 2010John H. Eisenach Intermediate physiological phenotype is the genetic and environmental influence on functional physiological characteristics with direct prognostic relevance to distant, more complex phenotypes, such as cardiovascular and metabolic disease. Increasingly available and affordable genotyping techniques have created an explosion of information on candidate gene variation and its relationship to intermediate physiological traits. Variation in ,-adrenoceptor genes is an intense focus of investigation because ,-adrenoceptors are: (1) ubiquitous in organ system distribution; (2) integral to a multitude of physiological processes; (3) well described in cardiovascular and metabolic disease; and (4) major pharmacological treatment targets. Furthermore, knowledge of functional gene variants in these receptors predates the description of the human genome. This review highlights the influence of common gene variation in the three ,-adrenoceptor subtypes on intermediate physiological phenotype predictive of cardiovascular disease and obesity. Although further information is needed to replicate this information across populations, this review condenses and summarizes growing trends in specific pleiotropic effects of ,-adrenoceptor polymorphisms and suggests which variants may be predictive of distant phenotype. [source] Isolation and identification of equol-producing bacterial strains from cultures of pig faecesFEMS MICROBIOLOGY LETTERS, Issue 1 2008Zhuo-Teng Yu Abstract Transformation of daidzein to equol was compared during fermentation of three growth media inoculated with faeces from Erhualian piglets, but equol was produced from only one medium, M1. Two equol-producing strains (D1 and D2) were subsequently isolated using medium M1. Both strains were identified as Eubacterium sp., on the basis of morphological and physiological characteristics, and 16S rRNA gene sequence analysis showed that strains D1 and D2 were most closely related to previously characterized daidzein-metabolizing bacteria isolated from human faecal and rumen samples, respectively. This suggests that the ability to metabolize daidzein can be found among bacteria present within the mammalian intestine. The results provided the first account of conversion of daidzein directly to equol by bacterial species from farm animals. These strains may be of importance to the improvement of animal performance, and the use of medium M1 could provide a simple way to isolate bacterial strains capable of transforming daidzein into equol. [source] Candida carvajalis sp. nov., an ascomycetous yeast species from the Ecuadorian Amazon jungleFEMS YEAST RESEARCH, Issue 5 2009Stephen A. James Abstract In the course of a yeast biodiversity survey of different ecological habitats found in Ecuador, two yeast strains (CLQCA 20-011T and CLQCA20-014) were isolated from samples of rotten wood and fallen leaf debris collected at separate sites in the central region of the Ecuadorian Amazonia. These strains were found to represent a novel yeast species based on the sequences of their D1/D2 domain of the large-subunit (LSU) rRNA gene and their physiological characteristics. Phylogenetic analysis based on LSU D1/D2 sequences revealed this novel species to be most closely related to Candida asparagi, Candida fructus, Candida musae and two as yet undescribed Candida species, with the six yeast taxa collectively forming a distinct species group within the Clavispora clade. The species name of Candida carvajalis sp. nov. is proposed to accommodate these strains, with CLQCA 20-011T (NCYC 3509T, CBS 11361T) designated as the type strain. [source] 2-D transmitral flows simulation by means of the immersed boundary method on unstructured gridsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2002F. M. Denaro Abstract Interaction between computational fluid dynamics and clinical researches recently allowed a deeper understanding of the physiology of complex phenomena involving cardio-vascular mechanisms. The aim of this paper is to develop a simplified numerical model based on the Immersed Boundary Method and to perform numerical simulations in order to study the cardiac diastolic phase during which the left ventricle is filled with blood flowing from the atrium throughout the mitral valve. As one of the diagnostic problems to be faced by clinicians is the lack of a univocal definition of the diastolic performance from the velocity measurements obtained by Eco,Doppler techniques, numerical simulations are supposed to provide an insight both into the physics of the diastole and into the interpretation of experimental data. An innovative application of the Immersed Boundary Method on unstructured grids is presented, fulfilling accuracy requirements related to the development of a thin boundary layer along the moving immersed boundary. It appears that this coupling between unstructured meshes and the Immersed Boundary Method is a promising technique when a wide range of spatial scales is involved together with a moving boundary. Numerical simulations are performed in a range of physiological parameters and a qualitative comparison with experimental data is presented, in order to demonstrate that, despite the simplified model, the main physiological characteristics of the diastole are well represented. Copyright © 2002 John Wiley & Sons, Ltd. [source] Physiological characteristics of the body fluid in lymphedematous patients postbreast cancer surgery, focusing on the intracellular/extracellular fluid ratio of the upper limbJAPAN JOURNAL OF NURSING SCIENCE, Issue 1 2010Hiromi SAKUDA Abstract Aim:, The aim of this research was to determine the physiological characteristics of patients with lymphedema following breast cancer surgery, based on differences between the quantity of body water in the right and left fingertips, with a view to establishing whether or not this simple measurement could serve as a predictive index for the onset of lymphedema. Method:, The research was conducted at a hospital in Hiroshima, Japan (August 2004 to December 2004). Observations were made on 39 female breast cancer patients who had undergone surgery and 45 healthy female participants. Additional information was collected via interviews with the individual participants. The quantity of body water in all the participants was measured by using a bioimpedance spectrum analysis system. Comparisons of the intracellular/extracellular fluid ratios (I/Es) were made between the edema patients and the non-edema patients, with further testing being done between the affected and unaffected sides of the upper limb in the edema patients. Results:, In the edema patients, significant differences were recognized between the affected side's upper limb I/E and the unaffected side's upper limb I/E. In relation to the affected side's upper limb I/E of the edema patients, even when the mean value and standard deviation were included, the value did not exceed 1.0 and the mean , 3 SD value of the affected side's upper limb I/E in the non-edema patients was 1.04. Conclusions:, The results suggest that measurements of the affected and unaffected sides' upper limb I/E showed a potential for use as a reliable predictive index for lymphedema. [source] Effect of some characters on the population growth of mite Varroa jacobsoni in Apis mellifera L colonies and results of a bi-directional selectionJOURNAL OF APPLIED ENTOMOLOGY, Issue 2-3 2002M. Lodesani Two lines of honey bees (Apis mellifera ligustica) were selectively propagated by instrumental insemination using the population growth of the Varroa mite as a criteria. Different infestation rates are at least partially genetic since selection produced significant bi-directional differences between lines over a period of three subsequent generations. There was no correlation between several behavioural and physiological characteristics which are potentially associated with Varroa resistance (hygienic behaviour, physical damage to mites, infertility of the intruding mites) and the development of the Varroa population after artificial infestation. There was a positive significant correlation between the total mites in the colonies and the amount of reared brood. Colony infestation was also positively correlated with the amount of honey harvested. [source] Characterization of the Enterobacteriaceae isolated from an artisanal Italian ewe's cheese (Pecorino Abruzzese)JOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2006C. Chaves-López Abstract Aims:, To evaluate some physiological characteristics of the Enterobacteriaceae isolated from Pecorino cheese. Methods and Results:, The production of organic acids, secondary volatile compounds, biogenic amines (BA) and the lipolytic and proteolytic activities of Citrobacter braakii, Enterobacter sakazakii, Escherichia coli, Kluyvera spp., Salmonella enterica ssp. arizonae and Serratia odorifera strains were determined in skim milk after 48 h of fermentation at 30°C. The proteolytic activity observed only in Ser. odorifera and Kluyvera spp. was confirmed by the peptide profiles of the pH 4·6-insoluble fraction using RP-HPLC; however, the lipase activity was evidenced in all the isolates of E. coli, Kluyvera spp. and Salm. enterica ssp. arizonae. During fermentation, all the strains utilized citric acid and produced significant quantities of putrescine followed by histamine, spermine and spermidine as well as acetic and lactic acid. Moreover, the major volatile compounds produced were ethanol, 2,3-butanedione, 3-hydroxy-2-butanone, 2-heptanone and acetone. Conclusions:, The Enterobacteriaceae of dairy origin possess many metabolic activities that could affect the sensory quality of the cheese in which they grow during ripening. Significance and Impact of the Study:, The important physiological characteristics possessed by Enterobacteriaceae confirm the complexity of the microbiota of Pecorino Abruzzese cheese, which influences the typical sensory properties of this product. [source] Changes in the Lactobacillus community during Ricotta forte cheese natural fermentationJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2000F. Baruzzi The loss of microbial biodiversity due to the increase in large-scale industrial processes led to the study of the natural microflora present in a typical little known dairy product. The community of lactobacilli was studied in order to understand the natural fermentation of Ricotta forte cheese. The combined use of RAPD analysis, 16S rDNA sequencing and physiological tests allowed 33 different strains belonging to 10 species of Lactobacillus to be characterized. RAPD analysis revealed the heterogeneity of both the Lact. kefiri and Lact. paracasei species. The sequence analysis of the large 16S/23S rRNA spacer region enabled Lact. plantarum to be distinguished from Lact. paraplantarum, two closely related species belonging to the Lact. plantarum group. The recovery of strains endowed with interesting physiological characteristics, such as strong stress resistance, could improve technological and/or organoleptic characteristics of Ricotta forte cheese and other fermented foods. [source] Strain isolation and optimization of process parameters for bioconversion of glycerol to lactic acidJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2009An-An Hong Abstract BACKGROUND: The crude glycerol from biodiesel production represents an abundant and inexpensive source which can be used as raw material for lactic acid production. The first aim of this investigation was to select a strain suitable for producing lactic acid from glycerol with a high concentration and productivity. The second aim was to obtain the optimum fermentation conditions, as a basis for large-scale lactate production in the future. RESULTS: Eight bacterial strains, which could aerobically convert glycerol to lactic acid, were screened from soil samples. One of the strains, AC-521, which synthesized lactic acid with a higher concentration, was identified based on its 16S rDNA sequences and physiological characteristics. These results indicated that this strain was a member of Escherichia coli. The optimal fermentation conditions for Escherichia coli AC-521 were 42 °C, pH 6.5, 0.85 min,1 (KLa). CONCLUSION:Escherichia coli AC-521 suitable for producing lactic acid from glycerol with high concentration and productivity was identified. After 88 h of fed-batch fermentation, both the lactic acid concentration and glycerol consumption reached maximum, giving 85.8 g L,1 of lactic acid with a productivity of 0.97 g L,1 h,1 and a yield of 0.9 mol mol,1 glycerol. Copyright © 2009 Society of Chemical Industry [source] Linking physiological traits to impacts on community structure and function: the role of root hemiparasitic Orobanchaceae (ex-Scrophulariaceae)JOURNAL OF ECOLOGY, Issue 1 2005G. K. PHOENIX Summary 1The hemiparasitic Orobanchaceae (ex-Scrophulariaceae) are characterized by a distinctive suite of ecophysiological traits. These traits have important impacts on host plants and non-host plants, and influence interactions with other trophic levels. Ultimately, they can affect community structure and functioning. Here, we review these physiological traits and discuss their ecological consequences. 2The root hemiparasitic Orobanchaceae form a convenient subset of the parasitic angiosperms for study because: they are the most numerous and most widely distributed group of parasitic angiosperms; their physiological characteristics have been well studied; they are important in both agricultural and (semi)natural communities; and they are tractable as experimental organisms. 3Key traits include: high transpiration rates; competition with the host for nutrients and haustorial metabolism of host-derived solutes; uptake of host-derived secondary metabolites; dual autotrophic and heterotrophic carbon nutrition; distinct carbohydrate biochemistry; high nutrient concentrations in green leaf tissue and leaf litter; and small (often hairless and non-mycorrhizal) roots. 4Impacts on the host are detrimental, which can alter competitive balances between hosts and non-hosts and thus result in community change. Further impacts may result from effects on the abiotic environment, including soil water status, nutrient cycling and leaf/canopy temperatures. 5However, for non-host species and for organisms that interact with these (e.g. herbivores and pollinators) or for those that benefit from changes in the abiotic environment, the parasites may have an overall positive effect, suggesting that at the community level, hemiparasites may also be considered as mutualists. 6It is clear that through their distinctive suite of physiological traits hemiparasitic Orobanchaceae, have considerable impacts on community structure and function, can have both competitive and positive interactions with other plants, and can impact on other trophic levels. Many community level effects of parasitic plants can be considered analogous to those of other parasites, predators or herbivores. [source] Clonal variation in morphological and physiological responses to irradiance and photoperiod for the aquatic angiosperm Potamogeton pectinatusJOURNAL OF ECOLOGY, Issue 5 2002Jörn Pilon Summary 1Widely distributed plants are exposed to contrasting gradients in irradiance and photoperiod across latitude. We investigated the relative contribution of local specialization and phenotypic plasticity to variation in plant growth for three clones of the aquatic angiosperm Potamogeton pectinatus L., originating from 42.5 to 68° N. Plants were grown at a factorial combination of two irradiances (50 and 350 µmol m,2 s,1) and three photoperiods (13, 16 and 22 h) and morphology, gas-exchange rate and biomass accumulation were recorded. 2The overall response to variation in irradiance and photoperiod was similar for all three clones. 3Differences in irradiance resulted in strong acclimative changes in morphological and physiological characteristics. At low irradiance, pronounced vertical shoot extension compensated for the limited plasticity in leaf area production, while photosynthetic capacity, apparent quantum yield and total chlorophyll concentration increased. As a result, biomass yield at the end of the experimental period was similar in both treatments. 4A decrease in photoperiod also resulted in plastic changes in morphology (increase of leaf biomass per unit plant biomass) and physiology (increase of photosynthetic capacity). However, these acclimative responses did not fully compensate for differences in photoperiod, since biomass was significantly lower under 13 and 16 h photoperiods than at 22 h. 5P. pectinatus is therefore phenotypically plastic, rather than locally specialized to differences in irradiance and photoperiod. [source] 42 Diversity of phycoerythrin-containing picocyanobacteria that share the same spectral phenotypeJOURNAL OF PHYCOLOGY, Issue 2003R. C. Everrroad Phycoerythrin (PE) is an important light-harvesting pigment for many marine picocyanobacteria. There are numerous spectral forms of PE, which differ in their ability to absorb blue and green wavelengths of light, depending on the precise chromophore composition. It remains unclear how the evolutionary history of this family of proteins relates to the diversity of the marine picocyanobacteria. In order to ascertain the level of diversity present in marine picocyanobacterial communities and to determine if specific spectral phenotypes are homologous or convergent, we have begun to examine the genetic diversity found in marine picocyanobacterial strains that share the same or similar spectral signatures for PE fluorescence. The strains we examined are all clonal cultures isolated from a range of environments, including the Arabian Sea and Black Sea. We report results from sequence data obtained using degenerate primers for 16S rRNA, rpoC1, and PE genes; we also examine the utility of taxonomically grouping these organisms by using physiological characteristics such as size and PE signature. [source] Morphological and Physiological Differentiation among Vegetative Compatibility Groups of Verticillium dahliae in Relation to V. longisporumJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2001K. Zeise Abstract Twenty-four isolates of Verticillium dahliae from various geographic regions and host origins were assigned to vegetative compatibility groups (VCG) based on complementation between nitrate-non-utilizing (nit) mutants. The VCG assignment was associated with clearly distinguishable morphological and physiological characteristics. Most isolates of VCG 2B produced deep black colonies, small conidia (3.62 × 0.02 , m), and spherical microsclerotia. They exhibited polyphenol oxidase (PPO) activity, high sporulation rate in shake cultures, fluorescence on sanguinarine-amended PDA (snPDA) and excretion of dark pigment on Czapek Dox agar. The isolates assigned to VCG 4B had significantly longer conidia (4.73 × 0.04 , m), spherical microsclerotia and white, fluffy colonies due to enhanced production of aerial mycelium. They excreted only traces of dark pigment, exhibited PPO activity, did not fluoresce on snPDA and had limited ability to sporulate in shake cultures. Except for lacking PPO activity the only heterokaryon self-incompatible isolate (HSI) was similar to VCG 4B. Ten isolates of Verticillium longisporum from cruciferous hosts did not produce nit mutants. They had clearly longer conidia (7.41 × 0.05 , m), formed elongate microsclerotia, and only poorly sporulated in shake cultures. They did not excrete dark pigment, lacked PPO, and failed to fluoresce on snPDA. The results indicate a clear morphological and physiological differentiation not only between the two species V. longisporum and V. dahliae but also among the VCGs of V. dahliae. [source] Diversity of algal endosymbionts (zooxanthellae) in octocorals: the roles of geography and host relationshipsMOLECULAR ECOLOGY, Issue 8 2005M. J. H. VAN OPPEN Abstract The presence, genetic identity and diversity of algal endosymbionts (Symbiodinium) in 114 species from 69 genera (20 families) of octocorals from the Great Barrier Reef (GBR), the far eastern Pacific (EP) and the Caribbean was examined, and patterns of the octocoral,algal symbiosis were compared with patterns in the host phylogeny. Genetic analyses of the zooxanthellae were based on ribosomal DNA internal transcribed spacer 1 (ITS1) region. In the GBR samples, Symbiodinium clades A and G were encountered with A and G being rare. Clade B zooxanthellae have been previously reported from a GBR octocoral, but are also rare in octocorals from this region. Symbiodinium G has so far only been found in Foraminifera, but is rare in these organisms. In the Caribbean samples, only Symbiodinium clades B and C are present. Hence, Symbiodinium diversity at the level of phylogenetic clades is lower in octocorals from the Caribbean compared to those from the GBR. However, an unprecedented level of ITS1 diversity was observed within individual colonies of some Caribbean gorgonians, implying either that these simultaneously harbour multiple strains of clade B zooxanthellae, or that ITS1 heterogeneity exists within the genomes of some zooxanthellae. Intracladal diversity based on ITS should therefore be interpreted with caution, especially in cases where no independent evidence exists to support distinctiveness, such as ecological distribution or physiological characteristics. All samples from EP are azooxanthellate. Three unrelated GBR taxa that are described in the literature as azooxanthellate (Junceella fragilis, Euplexaura nuttingi and Stereonephthya sp. 1) contain clade G zooxanthellae, and their symbiotic association with zooxanthellae was confirmed by histology. These corals are pale in colour, whereas related azooxanthellate species are brightly coloured. The evolutionary loss or gain of zooxanthellae may have altered the light sensitivity of the host tissues, requiring the animals to adopt or reduce pigmentation. Finally, we superimposed patterns of the octocoral,algal symbiosis onto a molecular phylogeny of the host. The data show that many losses/gains of endosymbiosis have occurred during the evolution of octocorals. The ancestral state (azooxanthellate or zooxanthellate) in octocorals remains unclear, but the data suggest that on an evolutionary timescale octocorals can switch more easily between mixotrophy and heterotrophy compared to scleractinian corals, which coincides with a low reliance on photosynthetic carbon gain in the former group of organisms. [source] Malassezia and Candida colonisation on glans penis of circumcised menMYCOSES, Issue 5 2005I. Atilla Arido Summary The Malassezia yeast are members of the normal human cutaneous flora in adults. They also are reported as part of the microflora of the male genital region in mostly uncircumcised males. It has been reported that Malassezia sympodialis and Malassezia globosa are the most frequent yeast belonging to the resident microflora of the penis as in other human skin areas. The aim was to evaluate the prevalence of Malassezia and Candida yeast colonisation on the glans penis of circumcised males. Impression preparations were made on modified Dixon agar. The isolates were identified by morphological and physiological characteristics. A total of 245 circumcised males were included in the study. Of the 245 patients examined, 55 (22.4%) were found to have a mycologically proven yeast fungi on their glans penis. In 17 (30.9%) Malassezia, in 36 (65.5%) Candida, in one (1.8%) Malassezia and Candida, and in one (1.8%) Saccharomyces strains were detected. Malassezia furfur (66.7%) was the most common species among the lipophilic yeast, followed by Malassezia globosa (11.1%), Malassezia obtusa (11.1%) and Malassezia slooffiae (11.1%). Candida albicans was the most common non-lipophilic yeast (46.0%), that was isolated among the other yeast, followed by unidentified Candida strains (18.9%), Candida tropicalis (8.1%), Candida glabrata (8.1%), Candida parapsilosis (8.1%), Candida zeylanoides (5.4%), Candida guilliermondii (2.7%) and Saccharomyces cerevisiae (2.7%). The results of this study showed that Malassezia species were also colonised like Candida on the glans penis of circumcised males. [source] Phenology of neotropical pepper plants (Piperaceae) and their association with their main dispersers, two short-tailed fruit bats, Carollia perspicillata and C. castanea (Phyllostomidae)OIKOS, Issue 2 2004Wibke Thies To relate differences in phenological strategies of a group of closely related plants to biotic (pollinators, dispersers) and abiotic (water, light) factors, we studied leafing, flowering, and fruiting phenology of 12 species of Piper (Piperaceae) in a neotropical lowland forest in Panama for 28 months. We asked how Piper may partition time and vertebrate frugivores to minimize possible competition for dispersal agents. Based on habitat preferences and physiological characteristics we discriminate between forest Piper species (eight species) and gap Piper species (four species). Forest Piper species flowered synchronously mostly at the end of the dry season. Gap Piper species had broader or multiple flowering peaks distributed throughout the year with a trend towards the wet season. Both groups of Piper species showed continuous fruit production. Fruiting peaks of forest Piper species were short and staggered. Gap Piper species had extended fruiting seasons with multiple or broad peaks. Both groups of Piper species also differed in their time of ripening and disperser spectrum. Forest Piper species ripened in late afternoon and had a narrow spectrum consisting mainly of two species of frugivorous bats: Carollia perspicillata and C. castanea (Phyllostomidae). Fruits of gap Piper species, in contrast, ripened early in the morning and were eaten by a broader range of diurnal and nocturnal visitors, including bats, birds, and ants. We conclude that the differences in flowering phenology of forest and gap Piper species are primarily caused by abiotic factors, particularly the availability of water and light, whereas differences in fruiting patterns are mostly influenced by biotic factors. The staggered fruiting pattern of forest Piper species may reflect competition for a limited spectrum of dispersers. The long and overlapping fruiting periods of gap Piper species are associated with a larger spectrum of dispersers and may be a strategy to overcome the difficulty of seed dispersal into spatially unpredictable germination sites with suitable light conditions. [source] Evolutionary adaptation to high altitude: A view from in utero,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009Colleen Glyde Julian A primary focus within biological anthropology has been to elucidate the processes of evolutionary adaptation. Frisancho helped to move anthropology towards more mechanistic explanations of human adaptation by drawing attention to the importance of the functional relevance of human variation. Using the natural laboratory of high altitude, he and others asked whether the unique physiology of indigenous high-altitude residents was the result of acclimatization, developmental plasticity, and/or genetic adaptation in response to the high-altitude environment. We approach the question of human adaptation to high altitude from a somewhat unique vantage point; namely, by examining physiological characteristics,pregnancy and pregnancy outcome,which are closely associated with reproductive fitness. Here we review the potent example of high-altitude native population's resistance to hypoxia-associated reductions in birth weight, which is often associated with higher infant morbidity and mortality at high altitude. With the exception of two recent publications, these comparative birth weight studies have utilized surnames, self-identification, and/or linguistic characteristics to assess ancestry, and none have linked ,advantageous' phenotypes to specific genetic variations. Recent advancements in genetic and statistical tools have enabled us to assess individual ancestry with higher resolution, identify the genetic basis of complex phenotypes and to infer the effect of natural selection on specific gene regions. Using these technologies our studies are now directed to determine the genetic variations that underlie the mechanisms by which high-altitude ancestry protects fetal growth and, in turn, to further our understanding of evolutionary processes involved in human adaptation to high altitude. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] Progress in Parasitic Plant Biology: Host Selection and Nutrient TransferPLANT BIOLOGY, Issue 2 2006H. Shen Abstract: Host range varies widely among species of parasitic plants. Parasitic plants realize host selection through induction by chemical molecular signals, including germination stimulants and haustoria-inducing factors (HIFs). Research on parasitic plant biology has provided information on germination, haustorium induction, invasion, and haustorial structures and functions. To date, some molecular mechanisms have been suggested to explain how germination stimulants work, involving a chemical change caused by addition of a nucleophilic protein receptor, and direct or indirect stimulation of ethylene generation. Haustorium initiation is induced by HIFs that are generated by HIF-releasing enzymes from the parasite or triggered by redox cycling between electrochemical states of the inducers. Haustorium attachment is non-specific, however, the attachment to a host is facilitated by mucilaginous substances produced by haustorial hairs. Following the attachment, the intrusive cells of parasites penetrate host cells or push their way through the host epidermis and cortex between host cells, and some types of cell wall-degrading enzymes may assist in the penetration process. After the establishment of host-parasite associations, parasitic plants develop special morphological structures (haustoria) and physiological characteristics, such as high transpiration rates, high leaf conductance, and low water potentials in hemiparasites, for nutrient transfer and resource acquisition from their hosts. Therefore, they negatively affect the growth and development and even cause death of their hosts. [source] Differential gene expression in senescing leaves of two silver birch genotypes in response to elevated CO2 and tropospheric ozonePLANT CELL & ENVIRONMENT, Issue 6 2010SARI KONTUNEN-SOPPELA ABSTRACT Long-term effects of elevated CO2 and O3 concentrations on gene expression in silver birch (Betula pendula Roth) leaves were studied during the end of the growing season. Two birch genotypes, clones 4 and 80, with different ozone growth responses, were exposed to 2× ambient CO2 and/or O3 in open-top chambers (OTCs). Microarray analyses were performed after 2 years of exposure, and the transcriptional profiles were compared to key physiological characteristics during leaf senescence. There were genotypic differences in the responses to CO2 and O3. Clone 80 exhibited greater transcriptional response and capacity to alter metabolism, resulting in better stress tolerance. The gene expression patterns of birch leaves indicated contrasting responses of senescence-related genes to elevated CO2 and O3. Elevated CO2 delayed leaf senescence and reduced associated transcriptional changes, whereas elevated O3 advanced leaf senescence because of increased oxidative stress. The combined treatment demonstrated that elevated CO2 only temporarily alleviated the negative effects of O3. Gene expression data alone were insufficient to explain the O3 response in birch, and additional physiological and biochemical data were required to understand the true O3 sensitivity of these clones. [source] Physiological and anatomical changes during the early ontogeny of the heteroblastic bromeliad, Vriesea sanguinolenta, do not concur with the morphological change from atmospheric to tank formPLANT CELL & ENVIRONMENT, Issue 11 2004G. ZOTZ ABSTRACT Two distinct morphological forms characterize the ontogeny of many epiphytic bromeliads. Smaller plants exhibit an atmospheric habit, while larger plants form water-impounding tanks. The study of the functional significance of heteroblasty in epiphytes is severely hampered by considerable size-related variation in morphological, anatomical and physiological parameters. To overcome this problem, plants of varying size of both atmospheric and tank form were included in the present study with Vriesea sanguinolenta. The results show that virtually all morphological, anatomical and physiological characteristics vary during ontogeny, but changes were rarely directly related to the step change in gross morphology. Changes were either: (1) gradual from smallest atmospheric to small tank (e.g. leaf divergence angles, reduction in photosystem II efficiency during drought, speed of recovery after drought); (2) there was no change between atmospheric and small tank, but a gradual or step change within the tank form (stomatal density, relationship of leaf N and specific leaf area); or (3) developmental patterns were more complicated with decreases and increases during ontogeny (photosynthetic capacity, carbon isotope ratios, abscisic acid levels during drought). Although the comparisons between ontogenetic phases were always confounded by size differences, a hypothetical small tank plant is expected to suffer higher water loss than a real atmospheric, whereas a hypothetical, large atmospheric plant would show reduced access to resources, such as nutrients, in comparison with the real tank. The present results are consistent with the notion of heteroblasty as an adaptation of early ontogenetic stages to drought, but highlight that size-related variation greatly modifies any difference directly associated with the step change from atmospheric to tank. [source] Long-distance transport of gases in plants: a perspective on internal aeration and radial oxygen loss from rootsPLANT CELL & ENVIRONMENT, Issue 1 2003T. D. COLMER ABSTRACT Internal transport of gases is crucial for vascular plants inhabiting aquatic, wetland or flood-prone environments. Diffusivity of gases in water is approximately 10 000 times slower than in air; thus direct exchange of gases between submerged tissues and the environment is strongly impeded. Aerenchyma provides a low-resistance internal pathway for gas transport between shoot and root extremities. By this pathway, O2 is supplied to the roots and rhizosphere, while CO2, ethylene, and methane move from the soil to the shoots and atmosphere. Diffusion is the mechanism by which gases move within roots of all plant species, but significant pressurized through-flow occurs in stems and rhizomes of several emergent and floating-leaved wetland plants. Through-flows can raise O2 concentrations in the rhizomes close to ambient levels. In general, rates of flow are determined by plant characteristics such as capacity to generate positive pressures in shoot tissues, and resistance to flow in the aerenchyma, as well as environmental conditions affecting leaf-to-air gradients in humidity and temperature. O2 diffusion in roots is influenced by anatomical, morphological and physiological characteristics, and environmental conditions. Roots of many (but not all) wetland species contain large volumes of aerenchyma (e.g. root porosity can reach 55%), while a barrier impermeable to radial O2 loss (ROL) often occurs in basal zones. These traits act synergistically to enhance the amount of O2 diffusing to the root apex and enable the development of an aerobic rhizosphere around the root tip, which enhances root penetration into anaerobic substrates. The barrier to ROL in roots of some species is induced by growth in stagnant conditions, whereas it is constitutive in others. An inducible change in the resistance to O2 across the hypodermis/exodermis is hypothesized to be of adaptive significance to plants inhabiting transiently waterlogged soils. Knowledge on the anatomical basis of the barrier to ROL in various species is scant. Nevertheless, it has been suggested that the barrier may also impede influx of: (i) soil-derived gases, such as CO2, methane, and ethylene; (ii) potentially toxic substances (e.g. reduced metal ions) often present in waterlogged soils; and (iii) nutrients and water. Lateral roots, that remain permeable to O2, may be the main surface for exchange of substances between the roots and rhizosphere in wetland species. Further work is required to determine whether diversity in structure and function in roots of wetland species can be related to various niche habitats. [source] Fish proteome analysis: Model organisms and non-sequenced speciesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 4 2010Ignasi Forné Abstract In the last decade, proteomic technologies have been increasingly used in fish biology research. Proteomics has been applied primarily to investigate the physiology, development biology and the impact of contaminants in fish model organisms, such as zebrafish (Danio rerio), as well as in some commercial species produced in aquaculture, mainly salmonids and cyprinids. However, the lack of previous genetic information on most fish species has been a major drawback for a more general application of the different proteomic technologies currently available. Also, many teleosts of interest in biological research and with potential application in aquaculture hold unique physiological characteristics that cannot be directly addressed from the study of small laboratory fish models. This review describes proteomic approaches that have been used to investigate diverse biological questions in model and non-model fish species. We will also evaluate the current possibilities to integrate fish proteomics with other "omic" approaches, as well as with additional complementary techniques, in order to address the future challenges in fish biology research. [source] Characterization of Acanthamoeba Isolates from Dust of a Public Hospital in Curitiba, Paraná, BrazilTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 1 2010ADRIANA O. COSTA ABSTRACT. Occurrence of Acanthamoeba in the hospital environment may represent a health risk for patients, since these organisms can cause severe opportunistic illness, such as keratitis, and also can harbor pathogenic agents. We analyzed the dust from some environments of a public hospital in Curitiba, Parana State, Brazil. Two distinct populations of Acanthamoeba were isolated in five locations and morphologically classified as group I and group II according to Pussard and Pons. Isolates were identified as Acanthamoeba by PCR using primers to amplify a region of 18S rDNA, which showed variation in the product length among the isolates. A cloned culture of group II showed greater growth at 37 °C and in media with 0.1, 0.5, and 1.0 M mannitol, which are the physiological characteristics of pathogenic Acanthamoeba. Monitoring the presence of Acanthamoeba in hospital units, as well as evaluating the pathogenicity of the isolates, can be an approach to alert the health professionals to improve the disinfection procedures and minimize the risks of treating this problematic disease caused by this protozoan. [source] | |||||||||||||||||||||||||||||||||||||