Patterns Of Substrate Use Research Articles

The Influence of Various Substrates on Power Generation in The Operation of Yeast Microbial Fuel Cells

Several carbon substrates were tried, including glucose commercial, pro analysis glucose, commercial sugar, and yeast extract - peptone - d glucose (YPD) medium to improve the efficiency of the single chamber microbial fuel cell (MFC). The power production of various electron donors was investigated using baker yeast Saccharomyces cerevisiae. Voltage and power density generation were used to establish the pattern of substrate use. In addition, electrochemical analysis of the anodic biofilm was performed. S. cervisiae was shown to successfully consume YPD medium by anode respiration with a higher power density of 18.40±1.98 mW/m2, followed by pro analysis glucose (9.41±1.15 mW/m2), commercial glucose (1.30±0.10 mW/m2), and commercial sugar (0.04±0.01 mW/m2). Furthermore, a clear relationship was established between power density generating rate and voltage output. Voltages produced were 0.16±0.02 V, 0.13±0.03 V, 0.03±0.01 V, 0.01±0.00 V for YPD medium, pro analysis glucose, commercial glucose, and commercial sugar, respectively in MFC. The weight of biofilm indicated that yeast attachment was significantly more common in YPD medium than in other MFC-operated media. This study discovered that the substrate type in the anodic compartment regulates the formation of anodic biofilm.

Environmental and phylogenetic aspects affect in different ways the acoustic niche of a frog community in southeastern Brazil.

One of the most important resources for reproduction in frogs is the acoustic space since the advertisement call, which is mostly used to attract females, may suffer interference when the acoustic space is widely filled. Other important resources are calling sites and adequate climatic conditions. We analyzed herein three dimensions of the acoustic niche of anurans (advertisement calls, calling period, and calling sites). We recorded 11 calling species of frogs in a tropical community. Species richness was negatively related to temperature, and daily activity was positively related to humidity. We also observed a greater niche overlap than expected by chance in calling periods. These results indicate that the climatic conditions should act as an environmental filter, synchronizing the calling period. The calling site was not shared among species, and no clear pattern of substrate use was observed. Regarding the acoustic dimension, we observe a phylogenetic signal in the dominant frequency of advertisement calls. Hierarchical cluster analysis also indicated a congruence between acoustic distances and phylogenetic relationships. Therefore, the dominant frequency of advertisement calls was constrained by phylogenetic relationships, indicating that it affects the partitioning and use of acoustic resources, an important dimension in reproductive activity in anurans.

Tokay geckos (Gekkonidae: Gekko gecko) preferentially use substrates that elicit maximal adhesive performance.

Gecko substrate use is likely influenced by adhesive performance, yet few studies have demonstrated this empirically. Herein, we examined the substrate use, adhesive performance and vertical clinging behaviour of Gekko gecko in captivity to investigate whether adhesive performance influences patterns of substrate use. We found that geckos were observed significantly more often on the substrate (glass) that elicited maximal adhesive performance relative to its availability within our experimental enclosures, indicating that geckos preferentially use substrates on which their adhesive performance is maximal. Our work here provides additional, yet crucial data establishing connections between adhesive performance and patterns of substrate use in captivity, suggesting the hypothesis that substrate preferences of free-ranging geckos should be correlated with adhesive performance. Clearly, further experimental and field research is necessary to test this hypothesis and identify other parameters that individually and/or collectively influence the habitat use of free-ranging geckos.

Paraburkholderia solitsugae sp. nov. and Paraburkholderia elongata sp. nov., phenolic acid-degrading bacteria isolated from forest soil and emended description of Paraburkholderia madseniana.

Two bacterial strains, 1NT and 5NT, were isolated from hemlock forest soil using a soluble organic matter enrichment. Cells of 1NT (0.65×1.85 µm) and 5NT (0.6×1.85 µm) are Gram-stain-negative, aerobic, motile, non-sporulating and exist as single rods, diplobacilli or in chains of varying length. During growth in dilute media (≤0.1× tryptic soy broth; TSB), cells are primarily motile with flagella. At higher concentrations (≥0.3× TSB), cells of both strains increasingly form non-motile chains, and cells of 5NT elongate (0.57×~7 µm) and form especially long filaments. Optimum growth of 1NT and 5NT occurred at 25-30 °C, pH 6.5-7.0 and <0.5% salinity. Results of comparative chemotaxonomic, genomic and phylogenetic analyses revealed that 1NT and 5NT were distinct from one another and their closest related type strains: Paraburkholderia madseniana RP11T, Paraburkholderia aspalathi LMG 27731T and Paraburkholderia caffeinilytica CF1T. The genomes of 1NT and 5NT had an average nucleotide identity (91.6 and 91.3%) and in silico DNA-DNA hybridization values (45.8%±2.6 and 45.5%±2.5) and differed in functional gene content from their closest related type strains. The composition of fatty acids and patterns of substrate use, including the catabolism of phenolic acids, also differentiated strains 1NT and 5NT from each other and their closest relatives. The only ubiquinone present in strains 1NT and 5NT was Q-8. The major cellular fatty acids were C16 : 0, 3OH-C16 : 0, C17 : 0 cyclo, C19 : 0 cyclo ω8c and summed features 2 (3OH-C14 : 0 / C16 : 1 iso I), 3 (C16 : 1 ω6c/ω7c) and 8 (C18 : 1 ω7c/ω6c). A third bacterium, strain RL16-012-BIC-B, was isolated from soil associated with shallow roots and was determined to be a strain of P. madseniana (ANI, 98.8%; 16S rRNA gene similarity, 100%). Characterizations of strain RL16-012-BIC-B (DSM 110723=LMG 31706) led to proposed emendments to the species description of P. madseniana. Our polyphasic approach demonstrated that strains 1NT and 5NT represent novel species from the genus Paraburkholderia for which the names Paraburkholderia solitsugae sp. nov. (type strain 1NT=DSM 110721T=LMG 31704T) and Paraburkholderia elongata sp. nov. (type strain 5NT=DSM 110722T=LMG 31705T) are proposed.

Microbial Community Level Physiological Profiles of Active Mud Volcano Soils in Andaman and Nicobar Islands

The aim of this work was to determine if any differences exist in the community-level physiological profiles (CLPP) in different regions of mud volcano. The microbial functional diversity in the four soils sampled in the vicinity of a mud volcano, Baratang, Andaman and Nicobar Islands, India, was determined using Biolog EcoPlates. Comparisons of the patterns of substrate use showed differences in the community composition, reflecting the heterogeneous distribution of microorganisms in this environment. The results showed statistically significant differences among different volcanic environments both by total colony-forming unit and by average well colour development. On the basis of similarity percentage analysis, it was found that i-erythritol was the most commonly used substrate, but substrates such as dl-glycerol phosphate (end mud volcano × point mud volcano), l-asparagine (end mud volcano × dried mud volcano) and ketobutyric acid (outside mud volcano × point mud volcano) were found in only one environment. The metabolic diversity varied depending on the environments compared, indicating specific utilization of compounds’ effect. Microbial response in terms of the overall metabolic activity in outside mud volcano was higher than in other inside mud volcano soils. To the best of our knowledge, this is the first attempt to use CLPP study in volcanic environments in the Andaman and Nicobar Islands.

Presence and expression of terminal oxygen reductases in strictly anaerobic sulfate-reducing bacteria isolated from salt-marsh sediments

In the anaerobic sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough genes were found encoding membrane terminal oxygen reductases of two types: a cytochrome c oxidase and a cytochrome bd oxidase, both enzymes are terminal oxidases typical of facultative or aerobic microorganisms (Heidelberg JF, et al., The genome sequence of the anaerobic, sulfate-reducing bacterium D. vulgaris Hildenborough. Nat Biotechnol 2004; 22: 554–9). To apprehend the presence of both oxidases in other sulfate-reducing bacteria (SRB), several assays were performed on isolates recovered from salt-marsh sediments in Portugal, representative of the different phylogenetic groups identified. Hybridization and PCR experiments for DNA sequencing were performed on the chosen isolates. Primers were selected to amplify conserved regions of cytochrome c oxidases and cytochrome bd oxidases taking into consideration alignment of corresponding subunit I sequences. The results showed that both oxidase genes are present on the chromosome of several isolates characterized as Desulfovibrio. These genes were shown to be transcribed, as demonstrated by Reverse Transcriptase-PCR experiments on total RNA. In order to assess the relative contribution of each oxidase to oxygen consumption, oxygen uptake was measured for each isolate and further characterized by the effect of cyanide on oxygen consumption. It was concluded that cytochrome bd oxidase was the terminal membrane oxygen reductase allowing oxygen consumption. In addition, it was observed that isolates containing cytochrome bd oxidase had higher resistance to air exposure, suggesting an important role of this enzyme in survival to air exposure. The pattern for the presence of oxygen reductase genes was compared to the physiological pattern of substrate use, which was determined for each isolate. Salinity tolerance, pH and temperature growth of each isolate were also analyzed.

Enzymatic switching for efficient and accurate translesion DNA replication.

When cyclobutane pyrimidine dimers stall DNA replication by DNA polymerase (Pol) delta or epsilon, a switch occurs to allow translesion synthesis by DNA polymerase eta, followed by another switch that allows normal replication to resume. In the present study, we investigate these switches using Saccharomyces cerevisiae Pol delta, Pol epsilon and Pol eta and a series of matched and mismatched primer templates that mimic each incorporation needed to completely bypass a cis-syn thymine-thymine (TT) dimer. We report a complementary pattern of substrate use indicating that enzymatic switching involving localized translesion synthesis by Pol eta and mismatch excision and polymerization by a major replicative polymerase can account for the efficient and accurate dimer bypass known to suppress sunlight-induced mutagenesis and skin cancer.

Mitochondrial Oxidative Substrate Selection in Porcine Bladder Smooth Muscle

Alterations in bladder smooth muscle (BSM) metabolism due to alterations in plasma lipid levels may be important with the increasingly high fat diets eaten by most Americans. To determine the susceptibility of BSM to lipotoxicity we examined the normal pattern of mitochondrial substrate selection in BSM and the ability of BSM to respond to changes in metabolic substrate provision. BSM strips were incubated in 5 mM 1-13C-glucose and 0 to 5 mM 1,2-13C-acetate. The pattern of substrate use measured by 13C-nuclear magnetic resonance using BSM extracts. BSM was also cultured for 4 days to elicit changes in cell phenotype. At physiological levels of glucose and acetate about 50% of the substrate used by mitochondria was glucose. When acetate concentration was changed from physiological levels (0.1 mM) to pathophysiological levels (0.5 mM), BSM was able to increase the use of acetate, while sparing the use of glucose and intracellular substrates, likely lipids. Above 0.5 mM acetate BSM was unable to further use acetate. With increasing acetate use anaplerosis increased, consistent with a depletion of tricarboxylic acid cycle intermediates. After 4 days of organ culture BSM mitochondria used significantly more unlabeled intracellular substrates and less 13C labeled glucose than control bladder, consistent with metabolic adaptation to increase lipid use, such as what occurs with hyperlipidemia. We conclude that BSM has modest plasticity of the pattern of mitochondrial substrate selection and excess lipid provision may be able to induce lipotoxicity in BSM, resulting in impaired detrusor function.

Substrate use and selection in sympatric intertidal hermit crab species.

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araçá Region, São Sebastião Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis.

Morphological correlates of substrate use in didelphid marsupials: implications for primate origins

AbstractThe ability of some mammals to forage on vines or terminal branches depends upon their grasping extremities. This study tests the functional link between use of small‐diameter supports and grasping abilities by comparing hand and foot proportions in didelphid marsupials. Metapodials and phalanges were measured for the hands and feet of six didelphid taxa characterized by different patterns of substrate use. Comparisons of hand and foot proportions demonstrate that Marmosa and Caluromys, didelphids that rely on vines or terminal branches, possess more prehensile extremities than Monodelphis, Didelphis, and Philander, which travel and feed mainly on the ground. Moreover, the proportions of the hand and foot of Marmosa and Caluromys are more similar to those of cheirogaleid primates than those of other didelphids. These morphological data corroborate the suggestion that the use of branches of small diameter was an important factor in the development of prehensile hands and feet in early primates.

Morphological correlates of substrate use in didelphid marsupials: implications for primate origins

The ability of some mammals to forage on vines or terminal branches depends upon their grasping extremities. This study tests the functional link between use of small-diameter supports and grasping abilities by comparing hand and foot proportions in didelphid marsupials. Metapodials and phalanges were measured for the hands and feet of six didelphid taxa characterized by different patterns of substrate use. Comparisons of hand and foot proportions demonstrate that Marmosa and Caluromys, didelphids that rely on vines or terminal branches, possess more prehensile extremities than Monodelphis, Didelphis, and Philander, which travel and feed mainly on the ground. Moreover, the proportions of the hand and foot of Marmosa and Caluromys are more similar to those of cheirogaleid primates than those of other didelphids. These morphological data corroborate the suggestion that the use of branches of small diameter was an important factor in the development of prehensile hands and feet in early primates.

Analysis of BIOLOG GN Substrate Utilization Patterns by Microbial Communities

BIOLOG GN plates are increasingly used to characterize microbial communities by determining the ability of the communities to oxidize various carbon sources. Studies were done to determine whether the BIOLOG GN plate assay accurately reflects the catabolic potential of the inoculum used. To gain insight into which populations of microbial communities contribute to the BIOLOG patterns, denaturing gradient gel electrophoresis and temperature gradient gel electrophoresis (TGGE) were used to assess the diversity of ribotypes in the inocula and individual wells of BIOLOG plates following incubation. These studies were done with microbial communities from the rhizosphere of potatoes and an activated sludge reactor fed with glucose and peptone. TGGE analyses of BIOLOG wells inoculated with cell suspensions from the potato rhizosphere revealed that, compared with the inoculum, there was a decrease in the number of 16S rRNA gene fragments obtained from various wells, as well as a concomitant loss of populations that had been numerically dominant in the inoculum. The dominant fragments in TGGE gels could be assigned to the gamma subclass of the class Proteobacteria, suggesting that fast-growing bacteria adapted to high substrate concentrations were numerically dominant in the wells and may have been primarily responsible for the patterns of substrate use that were observed. Similarly, the community structure changed in wells inoculated with cells from activated sludge; one or more populations were enriched, but all dominant populations of the inoculum could be detected in at least one well. This study showed that carbon source utilization profiles obtained with BIOLOG GN plates do not necessarily reflect the functional potential of the numerically dominant members of the microbial community used as the inoculum.

Spatial and temporal abundance, substrate partitioning and species co-occurrence in a guild of Neotropical blackflies (Diptera: Simuliidae)

Blackfly larvae were sampled monthly from two smallNeotropical mountain streams 500 m apart from each other in northernVenezuela during a 15-month period, and ten habitat variables weremeasured at two altitudes (800 and 900 m) to determine local spatialand temporal variations in abundance, stream variables, speciesco-occurrence, and substrate preference within the blackflyguild. The blackfly species composition of each stream was the same,with five species (in order of abundance): Simulium ochraceumWalker s.l., S. paynei Vargas, S. metallicum Bellardicytospecies E, Simulium sp., and S. horacioi Okazawa &Onishi. There were clear differences in community structurebetween streams (not among altitudes), although S. ochraceums.l. was the most abundant species in both habitats. Principal component andcorrelation analyses revealed that structural (great depth, width,flow, and discharge) and chemical (low conductivity) factors werethe stream variables best associated to the spatial distribution ofmost blackfly species. Blackfly abundance was greater in the largerstream. Larvae were most abundant on submerged rocks and fallenleaves, although the patterns of substrate use within the guildrevealed substrate partitioning among most blackfly species.There was one general annual peak of abundance at the end of therainy season. We suggest that blackfly community structure in theseNeotropical headwaters streams, over the small spatial scaleexamined here, is largely influenced by interactions among streamsize and velocity-related factors (width, streamflow, discharge andsubstrate availability-stability) and the rainfall regime.

Exogenous substrate uptake by fetal lambs during reduced glucose delivery

Normally, metabolism of exogenous glucose accounts for one-half of the normal fetal metabolic rate. When fetal glucose delivery is restricted for 2 wk, endogenous production increases to maintain glucose use. Such increased glucose production must originate either from increased uptake of other exogenous substrates (lactate or amino acids) or from use of endogenous substrates (via glycogenolysis or gluconeogenesis). Our purpose was to find if exogenous fetal substrate uptake increased during decreased fetal glucose delivery. Catheters were placed in eight lamb fetuses under general maternal anesthesia, and the animals were allowed 6 days to recover. Umbilical venoarterial blood concentration differences of antipyrine (during fetal antipyrine infusion), glucose, lactate, amino nitrogen-containing substances, and oxygen were measured before and after fetal glucose delivery was diminished by 3 h of maternal insulin infusion (5-10 mU.kg-1.m-1). Fetal substrate uptakes and substrate/oxygen quotients (i.e., the proportion of oxidative metabolism supported by complete oxidation of each exogenous substrate) were calculated. No increase occurred in the uptake of other exogenous substrates during deficient glucose delivery. Because even complete oxidation of all exogenous substrates did not meet fetal oxidative requirements, the fetus must oxidize endogenous substrates. If such a pattern of substrate use were to continue, fetal growth retardation would result.

Clinical applications of assessments of myocardial substrate utilization with positron emission tomography

Positron emission tomography (PET) permits sequential, noninvasive assessment of myocardial perfusion and metabolism. Based on the pattern of substrate use, clinical studies have utilized PET to define the location and extent of myocardial infarction, to identify areas of jeopardized but viable myocardium, and to assess the metabolic response of the myocardium to pharmacological therapy as well as to interventions such as coronary thrombolysis and coronary artery bypass surgery. The ability to noninvasively assess specific metabolic pathways should facilitate our understanding of normal myocardial metabolism, its perturbations with cardiac disease, and thereby improve the diagnosis and treatment of the biochemical processes underlying cardiac dysfunction.

Temporal and spatial variations in the behavior of shrubsteppe birds.

We documented patterns of activity and microhabitat use by breeding male Sage Sparrows (Amphispiza belli) and Brewer's Sparrows (Spizella breweri) in the semiarid shrubsteppe of northwestern U.S.A. to determine how their behavior varies in space and time and how these variations relate to environmental features. In analyses of several sites with multiple plots that were studied for 2-4 yr, the frequencies of activities and substrate use varied significantly with year, plot, and location. The major activities, foraging and singing, varied inversely with one another. Thus, although the general structure of the activity budgets of these species was stable (i.e. foraging and singing were always the most frequent activities), there was considerable variation in the quantitative details of their behavior in space and time. Using stepwise regression, we related these variations in behavior to variations in environmental features such as the densities of the same or other species, the number of species in the community, and coverages of the different substrate types. Few patterns emerged, and those that did were generally not in accord with our expectations. In particular, patterns of substrate use were not related to variations in coverages of those substrates. Sage Sparrows, for example, increased their use of sagebrush and grass with increasing grass coverage and with increasing densities of Sage Sparrows. Responses to both variables suggested nonlinear threshold patterns.We interpret the variations in behavior as indicating a loose coupling between behavior and proximate environmental conditions for these species. In such situations, the variability of behavior complicates attempts to test ecological hypotheses (e.g. behavioral niche partitioning) with data from a limited number of locations or years.

Temperature Regulation and Energy Metabolism in the Newborn

The goal of this book, as stated in the preface by Dr Sinclair, is to review our present understanding of the ways in which the human newborn transforms energy and regulates his body temperature in the extrauterine environment. Not only has this goal been achieved, but it has resulted in the best review of this topic available today. The book is arranged in nine chapters. It starts with a review of energy metabolism of the cell, which primarily emphasizes substrate use. The second chapter carries this theme to the newborn and reviews the present knowledge of energy requirements and patterns of substrate use in both the premature and the term infant. The middle portion of the book concerns itself with thermal physiology and includes chapters on heat loss and heat production of the newborn as well as a chapter on thermoregulation. These chapters constitute a comprehensive review of thermodynamic principles